Restoration ecology.pptxshshdhdheududrur

ODA BULTUM UNIVERSITY
DEPARTMENT OF FORESTRY
Lecture Note for the Course of Ecosystem Rehabilitation and
Restoration
Course Code: FoRe3065 Cr. Hr: 2
Target Group: 3rd Year Forestry Students
Academic Year: 2021/22 Semester: I
Compiled by: Mekonnen Beyene
E-mail Address: mekonnengurmu246@gmail.com
COLLEGE OF NATURAL RESOURCE AND
ENVIRONMENTAL SCIENCE

CHAPTER ONE
1. INTRODUCTION
1.1 Concepts and Definitions of Related Terms
♠ Ecosystem: Is the complex of living organisms, their physical
environment, and all their interrelationships in a particular unit of
space.
♠ Ecology: Ecology is the scientific study of organisms and how they
interact with the environment around them.
♠ Rehabilitation: Is defined as “repairing the ecosystem damages caused
by human exploitation, technological damages, etc., but this does not
mean making it as the same as it was before.”

Concepts and Definitions of Related Terms ……..
♠ Restoration: Restoration in context of ecology is also defined as
“action to re-instate ecological process, which accelerate recovery of
ecosystem structure, ecological functioning and biodiversity levels
towards those typical of climax ecosystem.
Ω It aims to return the species of plants, animals and other factors
to the original place.
♠ Sometimes, both terms of restoration and rehabilitation are used
interchangeably.
♠ However, both of them have separate conceptual meanings.

Concepts and Definitions of Related Terms ……..

1.2. Concepts and Definitions of Restoration Ecology
♠ Restoration ecology is defined as “the discipline of scientific inquiry
dealing with the restoration of ecological systems”.
♠ It is also defined as “the scientific process of developing theory to
guide restoration and using restoration to advance ecology”.
♠ It is used to provide a scientifically sound basis for the recovery of
degraded ecosystems and to produce self-sustaining systems.
♠ Restoration ecology is the interdisciplinary, complex science field,
involving science, society, policy etc.
♠ It deals with the restoration of ecological system.

Concepts and Definitions of Restoration Ecology ……

Concepts and Definitions of Restoration Ecology ……
♠ Ecological restoration: Is defined as “the practices of restoring
degraded ecological systems.
♠ Therefore, the difference between restoration ecology and ecological
restoration is that:
Ω Ecological restoration is the practice of restoring ecosystems as
performed by practitioners at specific project sites, whereas
Ω Restoration ecology is the science upon which the practice is
based.

1.3. The Rational for Restoration Ecology
♠ Land degradation is the leading cause of losses of ecosystem functions
such as nutrient cycling and climate regulation.
♠ These functions sustain life on earth.
♠ As a result, four key reasons why ecological restoration is the most
important endeavor of our time.
I. Healthy Soils Sustain Life on Earth
♠ Our food systems depend on healthy soils.
♠ The revival of plants, crops and forests depend on the revival of
degraded soils.

The Rational for Restoration Ecology ………
♠ This depends on the restoration of the complex relationships between
the soils, the plants and plethora of microbes, including fungi, bacteria
and viruses.
♠ Healthy soils is essential for plant growth and protection against
diseases.
II. Strengthening Our Relationship with Nature
♠ People who feel more connected to nature are more likely to engage
with actions such as wildlife conservation, recycling and supporting
environment.
♠ Importantly, connectedness can increase overtime through frequent
nature engagement.

III. Preserve Indigenous Knowledge with Nature
♠ Erosion of ecosystems can result in the erosion of culture: including
knowledge and language.
♠ This knowledge is often hyper-localized and has evolved over
thousands of years.
♠ It is vital to the health of many ecosystems and the livelihoods of
communities across the globe.
♠ Ecological restoration can help us to sustain the rich diversity of human
cultures on our planet by supporting relationships between humans and
the environment that are mutually advantageous.

♠ Ecological restoration should ideally be viewed as reciprocal: a mutually
beneficial relationship.
♠ Reciprocity is the basis for relationships in many indigenous cultures, and
will be fundamental to long-term successful restoration.
IV. Human Health is Dependent on Ecosystem Health
♠ The restoration of ecosystem is intrinsically linked to the restoration of
human health.
♠ E.g., COVID-19 pandemic, which caused over a million deaths
worldwide is a poignant reminder of how ecosystem degradation can
contribute to the emergence and spread of novel pathogens.

CHAPTER TWO
2. Causes and Characteristics of Ecosystem Degradation
2.1. Causes of Ecosystem Degradation
♠ The degradation of ecosystems is an environmental problem that
diminishes the capacity of species to survive.
♠ These can be caused naturally or by the activity of human being.
2.1.1. Natural Causes of Ecosystem Degradation
A. Flooding
♠ Floods can cause dangerous landslides; loss of crops and livestock;
disruption of normal drainage systems; discharge of raw sewage and
animal waste, and accelerated discharge of industrial and urban toxic
materials and nutrients into waterways.

Natural Causes of Ecosystem Degradation …….
♠ Flood can degrade the ecosystem in different ways as indicated
below:

i. Primary Production
♠ Flood is known to influence primary production by affecting water
clarity, oxygen, pH, and nutrient concentrations.
♠ Floods may initially inhibit primary production while water is high.
♠ On other hand, larger floods can transport excessive nutrients and
potentially stimulate excessive primary production (i.e., eutrophication)
or alter primary producer community composition, causing unfavorable
species to dominate.
♠ It is attributed to increase phosphorus (P) and nitrogen (N) loading
associated with flood events.

ii. Soil Formation
♠ Flooding causes over bank flow and changes the rate of sediment
deposition and erosional processes occurring between the river and
floodplain.
♠ Flooding can also cause upland erosion and incision, leading to
landslides in areas with hillslopes and mountainous terrain which pose
threats to people and animals.
iii. Drinking Water
♠ Floods can impact drinking water when contaminants and pathogens
are discharged into surface and underground drinking water sources.

♠ Any pollutants that are mobilized during flooding can impact
drinking water sources.
♠ Human wastes can also quickly infiltrate drinking water supplies
during flooding in areas that lack proper waste disposal.
♠ Additionally, animal wastes can contaminate drinking water by
contributing nutrients, pathogens, and metals.
♠ Metals stored in sediment can also be resuspended in aquatic
ecosystems or enter drinking water sources through connectivity
with contaminated water or runoff.

iv. Disease Regulation
♠ Extreme flooding is a leading cause of weather-related infectious
disease and can overwhelm sanitation systems, lowering the quality of
water treatment, and allowing sewage, industrial waste & agricultural
waste to mix with drinking water.
♠ Pathogen transmission can occur through ingestion of contaminated
drinking water or direct contact with flood waters.
v. Climate Regulation
♠ Floods impact heterotrophic processes tied to the production and
consumption of greenhouse gases (GHG: CO2, CH4 & N2O) as a
climate regulating ecosystem service provided naturally by soil
systems.

♠ These processes include:
 Aerobic respiration of a wide range of organic compounds in
floodwater (produces CO2),
 Methanogenesis (produces CH4), and
 Methane-oxidation (consumes CH4).
♠ The primary process tied to N2O production in soils is heterotrophic
denitrification, or the reduction of NO3
− into N2 gas, which leads to
production of N2O gas.
♠ In addition, flooding can transport large amounts of soil organic matter
into aquatic ecosystems, so it can be processed further & release CO2.

vi. Food Supply
♠ Food sources like fish, livestock, and crops can be affected by flooding.
♠ Small or seasonal flooding is advantageous for native fish populations
relative to invasive fishes occupying the same areas.
♠ However, extreme floods can destroy crops, drown livestock, and
impair fish catch by reducing fish density.
♠ Communities, which rely on subsistence farming and fishing are
especially vulnerable to food reduction during and after flooding.

B. Wild Fire
♠ Accidental or natural fires are another cause of ecosystem
degradation.
♠ This natural fire most probably affects areas of forest ecosystems.
♠ Wild fire has direct and indirect negative impact on ecosystem
through:
 Mobility of migratory animals and underground nests decreasing;
 Loss of nesting sites and young, especially for birds;
 Species composition both for fauna and flora changes to early
succession;

 Habitat loss and fragmentation;
 Shelter is temporarily decreased;
 Loss of food especially for herbivores;
 Microclimate is modified due to environmental imbalance.
(Temperature increase, humidity decrease, dry air creation etc.)
C. Invasive Species
♠ In ecosystems, alien species may become invasive and displace native
species;
♠ Cause the loss of native genotypes, modify habitats, change community
structure;

♠ Affect food-web properties and ecosystem processes;
♠ Impede the provision of ecosystem services.
♠ Many invasive alien species have potential to alter nutrient dynamics of
ecosystems.
♠ Alterations to nutrient dynamics within soils may further drive species
composition changes and affect net primary production, producing
dramatic changes in biodiversity and so far, ecosystems.
♠ Some of these species include: mesquites (Prosopis juliflora), parthenium
weed (Parthenium hysterophorus), water hyacinth (Eichhornia crassipes),
lantana weed (Lantana camara).

D. Climate Change
♠ Temperature in Ethiopia increased at about 0.2°C per decade.
♠ Precipitation, on the other hand, remained fairly stable over the last
50 years when averaged over the country.
♠ However, the spatial and temporal variability of precipitation is
high.
♠ The future changes in precipitation and temperature in Ethiopia that
have been projected by various global climate models are presented
in Figure below.

2.1.2. Anthropogenic Causes Ecosystem Degradation
A. Unsustainable Utilization
♠ Unsustainable utilization (over grazing/browsing, harvesting and
hunting) of biological resources is one of the major causes of
ecosystem degradation.
♠ For example, Fish species such as Labeobarbus (in Lake Tana), timber
tree species such as Hagenia abyssinica and medicinal plant species
such as Taverniera abyssinica are notable examples that have been
threatened due to over-utilization.
♠ Overgrazing/browsing by livestock in many ecosystems has also
contributed to the degradation of rangelands and forest ecosystems.

Anthropogenic Causes Ecosystem Degradation …….
♠ Over pumping or drainage of water from lakes and wetlands has resulted
in loss of habitats and species.
E.g., Lake Haramaya
♠ Additionally, over utilization forest resources is probably the most widely
recognized form of ecosystem degradation, since it so rapidly and
dramatically transforms the structure of the habitat.
♠ Such deforestation is caused for ecosystem services degradation like:
 Flood control,
 Atmospheric gases maintenance through carbon sequestration,

Anthropogenic Causes Ecosystem Degradation …….
 Control of vectors of disease and provision of timber.
B. Industrial Wastes and Pollution
♠ Industrial wastes and pollution are frequently cause for aquatic and
wetland ecosystem degradation.
♠ Major causes of pollution to aquatic and wetland ecosystems
particularly in Ethiopia are large- and small-scale factories such as:
 Brewery,
 Textile,
 Chemical,

Anthropogenic Causes Ecosystem Degradation ……
 Tobacco,
 Thread and garment,
 Paint factories
 Garages,
 Petrol stations,
 Tanneries,
 Slaughter houses,
 Market centres,
 Hospitals, etc.

Anthropogenic Causes Ecosystem Degradation…….
♠ Most of these factories do not have proper waste disposal systems and
are dumping and/or draining their wastes into nearby aquatic and
wetland ecosystems.
♠ This results in causing major damages to the biodiversity of the
ecosystems.
E.g., Akaki River and Koka reservoirs
C. Acid Rain
♠ Acid rain occurs when Sulphur Dioxide (SO2) from coal plant
emissions combines with moisture present in the air.
♠ A chemical reaction of this compound create acid precipitation.

Anthropogenic Causes Ecosystem Degradation ……..
♠ Acid rain can acidify and pollute lakes, streams, soil and other any
ecosystems.
♠ According to the U.S. Environmental Protection Agency (EPA), if
enough acid rain falls in a given environment, it can acidify the
water or soil to a point where no life can be sustained.
♠ Plants die off.
♠ The animals that depend upon them disappear.
♠ The condition of the ecosystem deteriorates.

Anthropogenic Causes Ecosystem Degradation ……..
D. Agricultural Runoff
♠ Farming system creates agricultural runoff issues.
♠ In this case, surface water washes over the soil and into lakes and
streams.
♠ When it does so, it carries the fertilizers and pesticides used on the
farm lands into water resources.
♠ For instance, fertilizers containing large amounts of phosphorus can
cause explosions of algae in lakes.
♠ As the algae die, bacteria start to breakdown the organic materials.

♠ It soon develops into a situation where bacteria are using up the
available dissolved oxygen in the water.
♠ Plants, fish, and other organisms begin to die off.
♠ The water becomes acidic.
♠ Like acid rain, lakes become dead zones with conditions so toxic that
neither plants nor animals can live in this ecosystem.
E. Urban Development
♠ As population increase, so does the need for land for home and farms.

♠ As a result, wetlands can be change to drained land.
♠ Grasslands and forest become ploughed over.
2.1.3. Habitat Conversion and Loss
♠ Conversion of natural forests, grazing lands, woodlands, and wetlands
to agriculture and settlement are some causes of ecosystems
degradation & biodiversity loss particularly in Ethiopia.
♠ In agriculture sector alone, the growth achieved between years 2005
and 2010 was due to 40% yield increment and 15% agricultural land
expansion.

Habitat Conversion and Loss …….
♠ To achieve targets, set for the growth of agriculture sector for years
2010 - 2030, land expansion of 3.9% per year is required.
♠ Under “business as usual” scenario, this will continue to affect
ecosystems and biodiversity of the country, especially of the high
woodland forest areas (MoFED, 2011).
2.1.4. Habitat Fragmentation and Isolation
♠ Fragmentation is the breaking up of large patches of native
vegetation into smaller and increasingly isolated patches.
♠ Fragmentation of a landscape reduces the area of original habitat
and increases the total lineal feet of edge.

Habitat Fragmentation and Isolation …….
♠ This favors species that inhabit edges at the expense of interior species
that require large continuous patches.
♠ Habitat fragmentation is the most serious threat to biological diversity
and is the primary cause of the present extinction crisis.
♠ Generally, habitat fragmentation diminishes the landscapes capacity to
sustain healthy populations in five primary ways:
1. Loss of original habitat
2. Reduced habitat patch size
3. Increased edge effect

Habitat Fragmentation and Isolation
4. Increased isolation of patches.
5. Modification of natural disturbance regimes.

2.1.5. Theory of Island Biogeography
♠ Islands are conventionally referred to as isolated lands in surrounding
waters.
♠ Because of the insular nature, habitats on oceanic islands are often
different from those on the nearest mainland even when latitudes
(climates) and the sizes (areas) are the same.
♠ E.g., islands often support unique species of proportionally more rare
and endemic species with small population sizes (e.g., reduced body
size or the so-called insular dwarfism and dispersal).
♠ Island biogeography studies the biogeography of the isolated units of
species diversity, related patterns and ecological processes.

Theory of Island Biogeography …….
♠ According to Island biogeography theory, two key island features:
area and isolation are jointly considered.
♠ It is predicted that species richness increases with island area but
decreases with isolation (distance from the mainland or other
islands.
♠ Additionally, the equilibrium island biogeography theory considers
both the immigration (I) and extinction rates (E).
♠ Equilibrium model suggesting number of species occurring on an
island represents a balance between immigration (in) and extinction
(out) as indicated on the below diagram.

Theory of Island Biogeography ……..

Theory of Island Biogeography ……..
♠ Proposed rates of extinction on islands would be determined mainly
by island size.
 Large near islands will support highest number.
 Small far islands will support lowest number.
 Small near and Large far will support intermediate number.

2.1.6 Demographic and Habitat Stochasticity and Species Extinction
♠ Demographic stochasticity refers to random variation in population
parameters such as birth rate, death rate and sex ratio.
♠ E.g., if a small population of a short-lived species experiences, by chance,
a low birth rate in two successive years, the immediate probability of
survival of the population may be greatly reduced.
♠ Habitat stochasticity is random change in habitat structure and related
phenomena by events like: floods, droughts, and other catastrophes that
may affect population spatial distribution.
♠ E.g., species that show high rate of dispersal but low levels of regional
stochasticity have a higher chance of long-term survival.

Demographic and Habitat Stochasticity and Species Extinction …
♠ It has also been proposed that dispersal is mostly advantageous to a
population if patch variation (regional stochasticity) is low.
♠ In general, species become extinct for the following reasons:
 Demographic and genetic stochasticity
 Destruction of wild habitats,
 Introduction of invasive species,
 Climate change, and
 Hunting and illegal trafficking

2.1.7 Loss of Heterozygosity
♠ Heterozygosity is the state of having different alleles with regard to a
given character.
♠ Allelic diversity determines a population’s ability to respond to long-
term selection over many generations, and ultimately the survival of
the population.
♠ Individual heterozygosity is expected to be correlated between parents
and their offspring.
♠ The expected correlation is maximal, approaching r = 0.50.
♠ Generally, loss of heterozygosity is exposed the species for inbreeding
and have long term consequences for species extinction.

2.1.8 Inbreeding Depression
♠ Inbreeding is the process of mating of two closely related individuals.
♠ The inbreeding coefficient of an individual refers to how closely related
its parents are.
♠ The major effect of inbreeding is the reduction in mean performance of
the population.
♠ Inbreeding tends to reduce the level of the fitness and consequently can
lead to loss of general vigour and fertility.
♠ This reduced fitness of populations caused by the manifestation of
deleterious recessive genes is termed inbreeding depression.

Inbreeding Depression ……
♠ Inbreeding increases homozygosity at all loci.
♠ This inbreeding depression can cause for: Increased homozygosity.
 Reduces fitness due to expression of deleterious recessive alleles.
♠ Decreased heterozygosity: Reduces fitness in cases when
heterozygotes have selective advantage.
♠ The most extreme form of inbreeding is selfing
Generation % Heterozygotes
0 100%
1 50%
2 25%
3 12.5%

CHAPTER THREE
3. ECOLOGICAL SUCCESSION
3.1 Definition
♠ Ecological succession is defined as “Gradual replacement of one
community by another in the development of vegetation towards a
climax”.
♠ It is also defined as gradual and continuous change in the species
composition and community structure over time in the same area.
♠ Environment is always kept on changing over a period of time due to:
i. Variations in the climatic and physiographic factors and
ii. The activities of the species of the communities themselves

3.2 Mechanisms of Successional Change
♠ The whole process of ecological succession is a complex process
completed through a number of sequential steps as follow:
1) Nudation: Succession begins with the development of a bare area
without any form of life.
♠ The area may be developed due to several causes such as landslide,
erosion, deposition, or other catastrophic agency.
♠ The cause of nudation may be:-
A. Topographic: Due to soil erosion by gravity, water or wind; deposition
of sand; landslide; volcanic activity; etc., the existing community may
be disappeared.

Mechanisms of Successional Change ……..
B. Climatic: - Glaciers, dry period, hails and storm, frost, fire etc.,
may also destroy the community.
C. Biotic: - Man is the most important agent responsible for
destruction of forests and grasslands.
 Other factors are disease epidemics due to fungi, viruses etc.
which destroy the whole population.
2) Invasion or Migration
♠ This is the successful establishment of a species in a bare area.
♠ The species reaches new site from any other area.

♠ The seeds, spores, or other propagules of the species reach the bare.
♠ This process is known as migration, is generally brought by air, water
and other agents.
3) Ecesis (Establishment)
♠ After reaching to new area, the process of successful establishment of
the species as a result of adjustment with the condition prevailing there
is known as Ecesis.
♠ In plants, after migration seeds or propagules germinates, seedlings
grow and adults start to reproduces.

♠ Only a few of them are capable of doing this under primitive harsh
condition and thus most of them disappear.
♠ Ecesis is considered to be complete, if the plants are able to sexually
reproduce in the given area.
♠ As a result of ecesis, species become established in the area.
4) Aggregation
♠ After successful establishment of a species as a result of reproduction,
the individuals of the species increase in number.
♠ As compared to earlier stages, there are a larger number of individual
of species that have aggregated in the given area.

5) Competition and Co-action
♠ After aggregation of a large number of species at the limited place,
there develops competition (inter as well as intraspecific).
♠ Competition is mainly for space & nutrition and individuals species
affect each other’s life in various ways and this is called co-action.
♠ Competition and co-action result the survival of fit individual and the
elimination of unfit individuals from the ecosystem.
♠ A species with wide reproduction capacity and ecological amplitude
only will survive.

6) Reaction
♠ The mechanism of modification of the environment, through the
influence of living organisms present on it is known as a reaction.
♠ As a results of the reactions, changes take place in soil, water, light
condition, temperature and many other factors of the environment.
♠ Due to environmental is modification, it is unsuitable for the existing
community which sooner or later is replaced by another community.
7) Stablisation (Climax)
Finally, community becomes more or less stabilized for a longer period of
time & it can maintain itself in equilibrium with the climate of area.

♠ This final community is not replaced, and is known as climax
community structure and energy flow.

3.3 Types of Succession
♠ There are two main types of Succession
1) Primary Succession: - Succession occurring in bare area or
newly exposed site that was not previously occupied by any sort of
living organism.
♠ In primary succession, the unoccupied terrestrial site is first
colonized by a few pioneer species which are often microbes,
lichens and mosses.
2) Secondary Succession: - Secondary succession starts at a site
that has already previously built-up substrate with already existing
living matter.

Types of Succession …….
♠ The action of any external forces, biotic intervention, fire etc., cause
the existing community to disappear.
♠ Thus, the area becomes devoid of living matter but its substratum,
instead of primitive is built-up.
♠ Secondary succession starts on a well-developed soil.
♠ Secondary succession is faster as compared to primary succession
which may often require hundreds of years.

3.4 Rates of Successional Change

3.5 The Role of Disturbance in Forest Ecosystem
♠ Forests are dynamic ecosystems and are almost always in some stage of
transformation after one or more disturbances.
♠ In geological processes, climatic forces, insects, plant diseases and the
activities of animals and humans have shaped the existing forests.
♠ Disturbances result in changes to ecosystem structure and function.
♠ In forest, this often involves death and removal of trees.
♠ Disturbance caused by physical forces: volcanoes, earthquakes, storms,
droughts & fire can affect the entire plant community, although some
species may withstand damage better than others.

The Role of Disturbance in Forest Ecosystem ……..
♠ Disturbances play an important role in shaping forest composition,
structure and development.
♠ With knowledge of disturbance regimes, managers can understand
key processes driving forest dynamics and gain insight into the
resiliency (ability to recover) and resistance (ability to withstand
change) of forest to future disturbance.
♠ As we improve our knowledge of these complex relationships, we
will able to anticipate & respond to natural disturbances & mimic
the desirable effects with management activities.

3.6 Effects of Forest Management on Succession
♠ Heavier cuts of forest cause, greater disturbance to the natural
succession process than do light selection cuts.
♠ Therefore, to regenerate certain species naturally following a
harvest, it is important to know:
 What successional stage these species typically occupy? and,
 What type of harvest will generate the desired conditions for
stand establishment?
♠ Again, woodland or forest owners has to minimize the decline in
forest growth in aging stands:

Effects of Forest Management on Succession ……….
♠ The most obvious solution is:
 To reduce the rotation length of the forest;
 To fertilize the forest to prevent a nutrient limitation;
♠ However, this approach is expensive and, not be cost-effective.
♠ Therefore, landowners can minimize the reduction in growth by
managing forests on an uneven-aged basis.
♠ Uneven-aged management, while not appropriate for all species, does
maintain a balance of healthy, vigorous trees and a smaller number of
mature trees.

CHAPTER FOUR
4. RESTORATION/REHABILITATION TECHNIQUES
4.1. The Rationale of Restoration Ecology in Ecological Succession
♠ Restoration is intrinsically linked to ecological succession.
♠ Consequently, the concept of restoration has evolved in conjunction with
the prevailing paradigms of successional theory.
♠ Restoration follows the same path as spontaneous succession, i.e., both
related to an increase in ecosystem composition and function.
♠ Even though succession represents a simultaneous increase in ecosystem
complexity and function, this is not always the case.

Rationale of Restoration Ecology in Ecological Succession ……..
♠ Successional trajectories often lead to communities dominated by
one or a few species that perform well in terms of relevant ecosystem
functions such as productivity, resources retention, etc.
♠ Therefore, restoration ecology as a science plays an important role in
ecological succession as it provides scientific guideline for the
successful practice of succession.
4.2 Existing Restoration Strategies/Techniques
♠ In Ethiopian context, ecosystem restoration is carried out through the
following strategies:

Existing Restoration Techniques ……..
4.2.1 Area Exclosure
♠ Area exclosures are common land areas, which are traditionally
‘open accesses, where wood cutting, grazing and other agricultural
activities are forbidden or strictly limited in order to promote the
restoration and natural regeneration of degraded ecosystem.
♠ Restoring degraded ecosystems through area exclosures has become
a common practice in the Ethiopian high lands.
♠ In size, area exclosure range from 1ha - 700 ha.
♠ They are usually established in steep, eroded and degraded areas
that have been used for grazing in the past.

♠ Natural features like large gullies and man-made features such as
roads usually demarcate the boundaries of an area exclosure.
♠ Because they are not fenced, guards are often hired by the local
administration on a food-for-work basis.
♠ Area exclosure management and protection is effective when the
local communities are impowered in overall activities.
♠ There are two strategies for using area exclosures in ecosystem
rehabilitation:
1) Biological and
2) Assisted

♠ Biological strategy protects an exclosure against livestock and
human interference, with no additional management required.
 Ecological succession arises from buried or dispersed seeds.
♠ Assisted strategy involves planting seedlings and construction of soil
and water conservation structures such as:
 Hillside terraces,
 Stone bunds and
 Micro basins to speed up succession by modifying
microclimate and soil conditions.

♠ Grass harvesting is normally restricted in area exclosures in order to
restore the soil seed bank.
♠ In some cases, grass is harvested for fodder once a year, using a cut
and carry system.
♠ This usually begins about 2 or 3 years after the establishment of the
area exclosure, once the grass has regenerated sufficiently.
♠ Honey production and the collection of medicinal plants are also
allowed.

♠ Generally, area exclosure plays an important role both in ecosystem
restoration and livelihood improvement as follows:
1) Increasing vegetation cover and biodiversity
2) Enhancing ecosystem carbon stock
3) Reducing soil erosion
4) Restoring soil fertility
5) Increasing dry-season water flow
6) Decreasing runoff and sediment load
7) Increasing ground water recharge
8) Increasing income and improving the livelihood of
smallholder farmers over the medium to long term.

4.2.2. Nurse Crops (Plantations) Deeper
♠ Nursing plant is another strategy of restoring degraded ecosystem.
♠ Nurse plants are those that facilitate the growth and development of
other plant species (target species) beneath their canopy b/c they:
 Offer benign microhabitats that are more favorable for seed
germination and/or seedling recruitment than their
surrounding environment for adjusting light, temperature, soil
humidity and nutrient as well as avoiding grazing.

♠ Nurse plants can also establish the seedlings of target species
through positive interaction between plants.
♠ Nursing effect is accomplished by the interactions between plants,
which influence community structure, dynamic performance and the
appearance or absence of specific species.
♠ The following points are important to be considered during the
development of nurse plants.

A) The Choice of Genotype (Native Vs Exotic?)
♠ In sites of low or intermediate degradation level, with largely intact
soils and sufficient germplasm sources for the next generation,
natural regeneration may be the best choice.
♠ Natural regeneration has an important role in promoting the
maintenance of genetic integrity & the recruitment of well-adapted
seedlings.
♠ However, planting selective species is advantageous in sites where:
i) Diverse native seed sources are lacking or insufficient,
ii) Seed sources suffer from genetic erosion, and/or

iii) Active planting is predicted either for especial advantage or for
the sake of fast growing.
♠ The first decision with respect to planting material concerns species
selection.
♠ In order to restore self-sustaining ecosystems and their services,
native species are generally preferred over exotics.
♠ Native species are expected to be adapted to local biotic and abiotic
conditions and thus support native biodiversity ecosystem function
to a greater degree than exotics.

♠ Additionally, it is important to choose tree species that are representative
of different functional groups based on adaptive traits.
B) Mix or Mono Plantation
♠ Mixed plantations may be designed to meet a wide variety of social,
economic, and environmental objectives.
♠ Use of mixed tree species increase:
 Management flexibility and
 Create options that ensure forest adaptability and
 Long-term productivity in a changing uncertain world.

♠ In mixed plantations, nurse trees may improve survival and growth
in seedlings by ameliorating the harsh micro climate that sometimes
occurs in open conditions: Example
 High light levels,
 Extreme temperature fluctuations, and
 Soil water stress because of competing ground vegetation.
♠ In addition, they may provide wind shelter, lower high-water tables
on poorly drained sites, and N-fixing tree species may increase N
availability.

C) Plantation Management and Restoration
♠ According to FAO (2000), forest plantation is defined as “those
forest stands established by planting and/or seeding in the process of
afforestation or reforestation.
♠ They are either of introduced or indigenous species which meet:
 A minimum area requirement of 0.5ha;
 Tree crown cover of at least 10 percent of the land cover; and
 Total height of adult trees above 5 m”.

♠ Plantation improves micro-climate of soil by adding biomass and
increasing biotic activities.
♠ Once the soil condition is improved, it can be home for many plant
species.
♠ In areas without regeneration sources or whenever existing
regenerations are unable to colonize, plantation plays a key role in
promoting forest structure and natural succession.
♠ However, some constraints impede the success of plantation and
often leads to failure.

♠ Some of the major problems faced in successful plantation activities
are:
 Shortcomings in species selection,
 Grazing animals,
 Extreme weather condition (wind, drought, frost, snow, etc.,),
 Fire,
 Insects, pests and diseases.
♠ Therefore, management of the plantation in response of such
conditions play important role in ecosystem restoration.

D) Framework (Target) Species
♠ The interaction between plants is dependent on characteristics of
each species, i.e., selection of target species would also influence the
restoration effect.
♠ Positive effects of nurse plant on shade-tolerant pine & shrubs in late
succession period are more than on pioneer species & shade-intolerant
species.
 E.g., the survival rate of Ambrosia dumosa in the open of arid environment is higher
than under shrubs b/c of its better adaptation in the open habitat, wherein, the
interaction between A. dumosa & the nurse plant is competition, so that this species
is not suitable as a target species.

♠ Age & size of target species should also be considered for the
balance of facilitation & competition through different life span.
♠ Nurse plant has a stronger positive effect when the target species is
young, whereas competition interaction is dominant when there are
older or bigger target plants.
♠ When the age and size of the nurse plant is similar to that of the
target species, the negative effect of tussock plants will be enhanced.

CHAPTER FIVE
5. ECOLOGICAL CORRIDORS AND STEPPING STONES
5.1 Ecological Corridors
♠ Ecological corridor or linkage is a swath of natural land, or stepping
stones of natural land, that is conserved to enhance the ability of
plants and wildlife to move among larger habitat patches.
♠ The term linkage is used to refer to a connectivity area with multiple
strands, whereas the term corridor suggests a single conduit.
♠ Corridor is defined as an area of habitat that is longer than it is wide
connecting two or more habitat patches.

Ecological Corridors …….
♠ The term corridor is used to refer to anything in the landscape that
facilitates movement.
♠ Corridors are often equated with connectivity, that is function as a
conduit for movement, and there are also other landscape elements
that influence connectivity.
♠ Corridors can exist naturally or be created by restoring habitat or
constructed through hard barriers.
♠ The term corridor has been used to refer to:
Greenbelt

 Buffers in urban areas
 Greenways
 Underpasses
 Green bridges
 Habitat alongside roads, waterways or railways
 Wind breaks (vegetative)
 Visual screens (vegetative)
 Hedgerows

♠ Corridors are usually thought as movement conduits.
♠ They can actually function in six ways.
♠ Corridors might function differently during the night compared with
the day, because impacts of the surrounding matrix might affect how
well it functions as a conduit.
1. Conduit: - Organisms or materials move along the corridor.
2. Habitat: - Organisms survive and reproduce in the corridor.
3. Filter: - Only some organisms can cross or move along the corridor
4. Barrier: - Organisms or material cannot cross the corridor.

5. Source: - Organisms emanate from the corridor into the connected
habitat or matrix b/c reproduction in the corridor exceeds mortality.
6. Sink: - Organisms or materials enter the corridor and are destroyed.
♠ Habitat corridors provide connectivity as follows:
i. Where landscape is modified and inhospitable to native species;
ii. Species that are habitat specialists or have obligate dependence on
undisturbed habitats;
iii. For species that have a limited scale of movement in relation the
distance to be traversed.

 In these case, the habitat corridor must provide resources to
sustain resident individuals.
iv. Where the goal is to maintain continuity of populations b/n
habitats, rather than simply fostering infrequent movements of
individuals;
v. Where the goal is the continuity of entire faunal communities;
vi. Where maintenance of ecosystem processes requires continuous
habitat for their function.

5.2. Types of habitat corridor
1. Natural Habitat Corridors: - Like streams and their associated
riparian vegetation usually follow topographic or environmental
contours and are the result of natural environmental processes.
2. Remnant habitat corridors
This may include:
 Strips of unlogged forest within clear-cuts,
 Natural woodland along roadsides, or
 Natural habitats retained as links between nature reserves,
♠ Are the result of clearing & alteration of surrounding environment.

Types of habitat corridor …….
3. Regenerated habitat corridors
♠ Occur as the result of regrowth of strip of vegetation that was
formerly cleared or disturbed.
E.g., Fencerows and hedges composed of plants that originate from
rootstocks, soil-stored seed, or seeds dispersed by wind or birds.
4. Planted habitat corridors
♠ Such as:
 Farm plantations,
 Windbreaks or shelterbelts,
 Many hedgerows and some urban green belts have been
established by humans.

Types of habitat corridor …….
♠ They are composed of non-indigenous or exotic plants species.
5. Disturbance habitat corridors:
♠ May include:
 Railway or road lines,
 Cleared transmission lines and other features that result from
sustained disturbance within a linear strip.
5.3 Different Aspects of Corridor/Connectivity
1. Structural Connectivity
♠ Connectivity is simply the extent to which habitat patches in the
landscape are linked physically.

Different Aspects of Corridor/Connectivity …….
♠ This structural concept of connectivity views the landscape from a
human perspective at human spatial scales.
♠ It is relatively straightforward to understand, measure and
communicate.
♠ However, it does not consider:
 How people and organisms actually move through and use the
landscape, or
 The consequences of these movements for ecosystem functions
and services.

2. Functional connectivity
♠ This functional connectivity includes the combined effects of both
the physical configuration of elements in the landscape and the
behavior of a particular species in that landscape.
 Behavior includes responses of species to movements within
different landscape elements;
 Species reactions to boundaries between habitat and non-
habitat.
♠ Different species vary in their ability to move successfully through
the matrix and corridors between their habitat patches.

 Some species cannot move at all through the matrix,
 Others may move relatively freely,
 Some may be unable to cross hard barriers such as fences or
roads.
♠ This means that the same landscape will have different levels of
functional connectivity for different organisms.
♠ Structural connectivity can exist without functional connectivity.
 This is happened when a particular species does not move
through the corridors between habitat patches.
 E.g., Plant species with poor dispersal abilities.

♠ Functional connectivity can exist without structural connectivity.
 This is happened if a species is able to use and move
successfully through the matrix between habitat patches.
 This can be for species with relatively general habitat
requirements like badgers or highly mobile species like birds.
♠ However, the habitat patches must be relatively close together in
relation to the species’ movement abilities.
♠ Structural & functional connectivity are synonymous if a species
tends to move only within habitat patches & along physically
connected habitat corridors.

 This is for species with very specific habitat requirements and
relatively limited mobility such as dormice and water voles.
5.4 Advantages of Corridor
A. Assist the movement of individuals through disturbed landscapes
♠ This includes:
 Wide-ranging species that move b/n habitats on a regular basis;
 Nomadic or migratory species that move between irregular or
seasonally-varying resources;
 Species that move b/n habitats at d/t stages of their life-cycle.

Advantages of Corridor …….
B. Increase immigration rates to habitat isolates
 Which could maintain a higher species richness and diversity;
 Supplement declining populations, thus reducing their risk of
extinction;
 Allow re-establishment following local extinction;
 Enhance genetic variation and reduce the risk of inbreeding
depression.
C. Facilitate the continuity of natural ecological processes in
developed landscapes.

Advantages of Corridor ……
D. Provide habitat for many species
 Including refuge and shelter for animals moving through the
landscape; plants and animals living within linkages.
E. Provide ecosystem services
 Such as maintenance of water quality,
 Reduction of erosion, and
 Stability of hydrologic cycles.

5.5 Disadvantages of Corridor
1. Increase immigration rates to habitat isolates
 May facilitate the spread of unwanted species such as pests,
weeds and exotic species;
 Facilitate the spread of disease;
 Introduce new genes which could disrupt local adaptations and
co-adapted gene complexes (outbreeding depression), and
 Promote hybridization between previously disjunct taxonomic
forms (races, sub-species).
2. Increase exposure of animals
 To predators, hunting or poaching by humans, or other sources
of mortality (e.g., road kills); competitors or parasites.

Disadvantages of Corridor ……
3. Act as ‘sink habitats’
4. In which mortality exceeds reproduction, and thus functions as a
‘drain’ on the regional population.
5. Facilitate the spread of fire or other abiotic disturbances.
6. Establishment and management costs could reduce the resources
available for more effective conservation measures, such as the
purchase of habitats for endangered species.

5.6 Stepping Stones
♠ Stepping stones is One or more separate patches of habitat in the
intervening space between ecological isolates, that provide resources
and refuge to assist animals to move through the landscape.
♠ Allowing species for moving between large patches.
♠ Are important in fragmented landscapes.
♠ Loss of a stepping stone can often:
 Inhibit movement,
 Increasing patch isolation.

Stepping Stones ……
♠ Some times, the distance between stepping stones can be exceed a
threshold at w/c specific species is unwilling/ incapable of crossing.
♠ These critical gaps should often be restored.

Stepping Stones ……
Key Consideration for Managing Gaps
i. The greater the contrast between the gap and the corridor plant
community, the narrower the gap must be to minimize a barrier.
ii. Smaller species will generally have smaller gap threshold.
iii.Species requiring specialized habitats will have smaller gap
threshold.
iv.For visually-oriented species, gap thresholds may be determined
by the ability to see the next stepping stone or across the gap.
v. In riparian corridors, restore gaps in higher order streams first to
provide the greatest benefit for biodiversity.

CHAPTER SIX
6. SOIL SEED BANK, SEED RAIN AND RESTORATION
6.1. Soil Seed Bank and Restoration
♠ Soil seed bank is a natural storage of seeds in the:
 Leaf litter,
 On the soil surface
 In the soil of many ecosystems
♠ It serves as a repository for the production of subsequent generations
of plants to enable their survival.
♠ It contributes to the diversity and dynamics of most plant
communities.

Soil Seed Bank and Restoration …..
♠ Similar to the above-ground community of plants, seed banks are
dynamic in their composition and abundance and are responsive to
factors that influence seed inputs and losses.
♠ Moreover, because of vary in seed longevity among taxa, the
composition and diversity of the seed bank can differ substantially
from that of the local vegetation.
♠ Removal of topsoil to reduce nutrient inputs and to expose seeds of
target species buried at depth may facilitate germination.
♠ Seed longevity of grassland species in the soil is generally short.

Soil Seed Bank and Restoration …..
♠ However, some grassland taxa do retain viable seed banks for
decades under woody plant cover.
♠ Weedy species dominate the persistent seed banks of many
ecosystems.
♠ Growth is typically rapid, they have the potential to compete with
target species in restoration efforts.
6.1.1 Types of Seed Bank
♠ The soil seed bank has been classified into transient and persistent
seed depending on whether seeds persist in the soil for less or more
than a year.

Types of Seed Bank ……
1) Transient: - Seed persistence in the soil for less than 1 yr. (X < 1).
2) Persistent
A) Short-term-persistent
♠ Seed persistence in the soil for at least 1 year, but less than 5 years
(1 ≤ X ≤ 5).
♠ It plays a role in the maintenance of plant populations after a bad
year (e.g., poor seed set in a dry year).
B) Long-term persistent
♠ Seed persistence in the soil for at least 5 years (X ≥ 5

Types of Seed Bank …….
♠ It may contribute to the restoration of destroyed or degraded plant
communities.
6.1.2. Function of Soil Seed Banks in Ecosystem Restoration
♠ Persistent soil seed banks reflect:
 Long-term vegetation history of composition, density and
distribution;
 Play an important role in determining future vegetation
composition, especially following perturbations.
♠ Persistent soil seed banks have clear relevance for the restoration of
plant communities.

Function of Soil Seed Banks in Ecosystem Restoration….
♠ Persistent soil seed banks are an important tool to restore local plant
communities after abandonment of:
 Human use,
 Fire
 Other diverse forms of direct destruction of above-ground
vegetation.
♠ Plants are different in their life history of their dependence on
persistent soil seed banks.
♠ Only plants with persistent seed banks will recover spontaneously
from soil seed banks if unfavourable conditions lasted.

Function of Soil Seed Banks in Ecosystem Restoration….
♠ Many of the most endangered species do not have persistent soil
seed banks.
♠ Conversely, plant populations that can be restored from persistent
seed banks are often widespread or invasive species.
♠ In exceptional cases, restoration from soil seed banks are effective
for rare or threatened species.
♠ This seems to be the case even when local communities remain
intact but are fragmented.

6.2. Seed Rain and Restoration
♠ Seed rain is defined as: “deposition of seeds spread by bird, wind,
humans, and animals usually pertaining to non-native species
degrading natural ecosystems.
♠ Seed rain is also describing the spread of vegetative or seed
propagules crossing public and private property boundaries.
♠ Seed rain is a critical step in plant life cycle, as it represents a
demographic bridge between the adult and seedling stage.
♠ Seed rain reflects species dispersal potential.
♠ Therefore, it indicates potential for change of the standing
vegetation.

Seed Rain and Restoration …….
♠ It allows the arrival of seeds into suitable uncolonized microsites.
♠ For the implication of biological invasions and restoration ecology
by revealing relevant information about:
 How target species can reach a restored site and
 Whether seed rain is effective & efficient to restore a given site.
6.2.1. Mechanisms of Seed Dispersal
A) Seed Dispersal by Animals
♠ Most flowering plants use animals to carry seeds.
♠ Some flowering plants produce edible fruits.

Seed Dispersal by Animals …..
♠ These juicy, tasty, sweet & colorful fruits often have seeds that are
animal dispersed.
♠ Some fruits become fragrant and brightly colored to advertise their
ripeness to animals.
♠ Animals eat fruits and defecate.
 When animal ingests the fruit, the animal digests the fleshy part.
 In this case, seed coat usually prevents the digestion of the seeds.
 The tough seeds usually pass unharmed through the digestive
tract.

♠ Then, animal deposits the seeds, along with a fertilizer supply,
miles from the parent plant where the fruit was eaten.
♠ Note that
 One of the most common colors of fruits is red.
 A color insects cannot see very well;
 Therefore, most of the fruit is saved for animals large enough
to disperse the seeds.

Bright fruits for advertise defecate Animals eat fruits & defecate Red color of fruit is blind to insects
♠ Some flowering plants have fruits modified as burrs that cling to
animal fur or the clothes of humans.
♠ Small animals collect seeds and bury them as food stores for a later
date when food is scarcer.

♠ These animals do not return to collect these seeds, and they leave
them planted in the ground.
♠ For instance,
 Squirrels bury oak acorns and sometimes forget where they
buried them, thus planting a tree far away from the parent plant;
 Blue Jays also bury acorns usually remember where they bury
them, but at times they bury more than they need.
 This leaves some acorns in the ground, which may eventually
sprout.

Seed dispersal by cling to animal fur Animals collect seeds and bury seeds Squirrels bury oak acorns
B) Seed Dispersal by Wind
♠ Small, hard, dry fruits are often dispersed by wind.
♠ Some plants have seeds within fruits acting as kites or propellers
that aid in wind dispersal.

Seed Dispersal by Wind ……
♠ Characterized by:
 Winged
 Small in size
 Hard
 Dry fruits
 Produce large № of seeds

Seed Dispersal by Wind ……
♠ Most of these plants produce a large number of seeds, but most of
the seeds will not produce mature plants.
 Their large number and ability to disperse to new habitats
ensure that at least some will grow & eventually produce seeds
themselves.
C) Seed Dispersal by Water
♠ Some small, hard, dry fruits are also dispersed by water.
♠ These plants have seeds that float and travel on the water until
washed up on shore.

Seed Dispersal by Water …..
 E.g., fruit such as the large seeded pod of the 'Black bean'
Castano-spermum australe (below) float well in water.
♠ Some plants produce a moderate number of very large seeds.
♠ Seeds with a high amount of nutrients, which ensures the survival of
most of the offspring.

D) Seed Dispersal by Fire
♠ The cases, where natural fires are common, many seeds require
intense heat to break dormancy.
♠ Seedlings are therefore most abundant after fire has cleared away
competing vegetation.
E) Seed Dispersal by Popping
♠ Some seeds have evolved a popping mechanism for short distance
dispersal.
♠ As the seed mature, the pod/ husk dry out & start to shrink around
the seeds.
♠ After it shrinks so far, it may “pop” and scatter the seeds around.

Seed Dispersal by Popping ……
 Touch-me-nots are aptly
named.
 The seed capsules develop
from mid-summer through
fall.
 If touched, picked or
otherwise disturbed, they
rupture like a broken
spring; projecting their
seeds several feet.

CHAPTER SEVEN
7. RESEEDING AND PLANTING
7.1. Seeding for Ecosystem Rehabilitation and Restoration
♠ Direct seeding, in which tree seeds are introduced directly on the
regeneration site, is cheaper and easier alternative than transplanting
seedlings previously produced in nurseries.
7.1.1 Advantages of Direct Seeding
♠ Ability to sow large areas rapidly by hand or with broadcasting
machinery.
♠ Lower cost compared with transplanting seedlings.

Advantages of Direct Seeding …….
♠ Field grown plants are often less prone to toppling and have
unhindered taproot formation compared with container-grown
seedlings.
♠ Container-grown seedlings are developed with restricted, ‘cork-
crew’ roots and distorted taproots.
7.1.2 Disadvantages of Direct Seeding
♠ Difficulties in sourcing large quantities of viable seed.
♠ Lack of information on optimum sowing time for many species.
♠ Variability in starting and duration of germination.

Disadvantages of Direct Seeding …….
♠ Less flexibility to control conditions for seed germination and early
seeding growth.
♠ Predation of seed and seedlings.
♠ The need to control the intense competition from existing
vegetation, particularly grasses.
♠ When the viability of seeds is lower than 85%, it is best to use these
seeds for sowing in nurseries.
♠ Seedlings after direct seeding in the first two years after
germination, require more care, cleaning work, and supervision than
seedlings planted from nurseries.

7.2. Planting for Ecosystem Restoration and Rehabilitation
♠ Plantation are commonly established using a single species
monoculture because it is the easiest to manage.
♠ Some landscape biodiversity can be increased if mixed species
polyculture is used.
♠ Biodiversity gains from mixed species plantations are usually
diffident since most of them contain relatively small numbers of tree
species.
♠ But, there may be production or financial advantages, biodiversity
and ecosystem restoration gains from using mixed species plantings.

Planting for Ecosystem Restoration and Rehabilitation …..
♠ These benefits result from better site use, improved tree nutrition
and less insect or pest damage.
♠ The following table indicates the role of mixed plantation in
ecosystem rehabilitation and restoration.

♠ Additionally, in restoration practice, the right tree species for the
right place and the right purpose are needed.
♠ The major challenge in tree-based restoration is the need to work
with many tree species at the same time.
♠ Planting for landscape restoration requires the supply of genetically
diverse, healthy & productive tree species matched to planting sites.
♠ Often diverse planting materials are not available, and many land
restorationist end up using whatever material that is locally
available.

♠ This practice is fraught with mismatch of planting site and tree and
with the potential risk of using invasive species.
♠ Frequently such trees fail to grow adequately, & restoration is lost.
♠ To address such shortcoming, World Agroforestry (ICRAF) has
developed tools such as:
 Agroforestry database and
 Vegetation maps
♠ These may provide knowledge on species-specific characteristics for
most tree species for areas that are considered for restoration.

CHAPTER EIGHT
8. RESTORING SOIL FERTILITY
8.1. Causes and Consequences of Soil Degradation
♠ Of the 5.5 billion people living in developing countries in 2014 (Van
Pham et al., 2014), a large proportion of them depend on agriculture
for their livelihood.
♠ In fact, one billion of these people are smallholders who cultivate
less than two hectares of land.
♠ With limited resources and poor access to inputs, management of
soil quality is essential to strengthen and sustain ecosystem services.

Causes and Consequences of Soil Degradation ….
♠ Soil degradation is a 21st century global problem that is especially
severe in the tropics and sub-tropics.
♠ Some estimates indicate degradation decreased soil ecosystem
services by 60% between 1950 and 2010.
♠ Accelerated soil degradation has reportedly affected as much as 500
million hectares in the tropics and globally 33% of earth’s land
surface is affected by some type of soil degradation.
♠ Soil degradation can also dampen economic growth, especially in
countries where agriculture is the engine for economic development.

Causes and Consequences of Soil Degradation ….

8.2. Importance of Soil Restoration
♠ Restoring the soil is essential in ecosystem services and plant and
animal health.
♠ Indeed, well restored soil can provide the following basic functions.
A. Production of Food, Fiber and Energy
♠ Soil is a heterogeneous mixture of:
 Minerals,
 Decomposing organic matter and
 Living biomass
♠ This supplies nutrients for plant growth and higher trophic levels.

Importance of Soil Restoration …….
♠ Plant production can be used:
 Directly for food;
 Indirectly as food for livestock;
 Converted to fuel (lignocellulosic energy) and
 Other consumer products (e.g., lumber, paper and textiles).
B. Erosion Control
♠ Erosion is the movement of soil by wind and water.
♠ Although a natural process, land use change and disturbance to soil
have accelerated the rate of erosion worldwide.

Importance of Soil Restoration ……
♠ Sediments from agriculture and urban contains:
 Minerals,
 Nutrients,
 Heavy metals and
 Dissolved organic carbon
♠ These change the functioning of aquatic ecosystems.
♠ Thus land-use practices that promote development of stable soil
structure are prerequisite for reducing the export of particle-bound
nutrients from terrestrial watersheds to aquatic ecosystems.

♠ Erosion disproportionately removes the light and soluble fraction of
organic carbon (C) from the terrestrial ecosystem.
♠ As dissolved organic carbon is transported through soil and to
aquatic ecosystems, it becomes prone to decomposition.
♠ Respiration of labile organic C compounds to carbon dioxide (CO2)
alters C inputs and C:nutrient ratios in terrestrial and aquatic
ecosystems.
C. Balancing Nutrient Abatement
♠ Fertilizer inputs, livestock production and urban development are
major sources of nitrogen (N) and P to surface waters.

♠ These nutrients are responsible for eutrophication and are the
leading cause of hypoxia at the mouth of rivers.
♠ The global availability of reactive N has increased as a result of:
 Industrial-fixation of for fertilizer production,
 Increased biological N fixation through mass production of
legumes,
 Land clearing and
 Combustion of fossil fuels.

♠ The primary sources of P in surface waters are from:
 Fertilizer in overland flow,
 Erosion and
 Livestock containments.
♠ Hence, reducing N and P loading in aquatic ecosystems will require
better land and soil management practices to reduce the availability
of these nutrients for loss from terrestrial ecosystems.

D. Infiltration and Disturbance Regulation
♠ Undisturbed soil with complex hierarchical aggregate structure has
higher infiltration and water holding capacity than physically
disturbed soil.
♠ Such types soil reduces:
 Runoff,
 Sedimentation and
 Nutrient pollution.
♠ Long-term tillage, operation of heavy equipment, topsoil removal
and high livestock densities compact soil.

♠ Soil compaction impedes the:
 Infiltration of water,
 Reduces water residence time for nutrient abatement and
 Increase the quantity of water in surface runoff.
♠ Thus, protecting undisturbed soils containing natural vegetation,
especially in floodplains can:
 Reduce flood severity through greater infiltration into the soil
 Reduce water loss via transpiration through plants.

♠ Further, soil management by improving soil health will increase
organic matter, and concomitantly, water holding capacity.
♠ In drier regions, managing soil to promote water-holding capacity
and infiltration can lessen drought effects.
♠ In these ways, infiltration:
 Moderates severity of disturbance (flooding or drought),
 Increases water supply,
 Improves water quality and
 Promotes primary production.

E. Greenhouse gas and Climate Regulation
♠ Global warming projections are attributed mostly to increase levels
of CO2, nitrous oxide (N2O) & methane (CH4) in the atmosphere.
♠ Although agriculture has contributed a relatively small amount of
CO2 to the atmosphere compared to combustion of fossil fuels.
♠ But, it is estimated that agricultural practices are responsible for
more than 50% and 80% of anthropogenic CH4 and N2O emissions
respectively.

♠ Therefore, to reduce CO2 and other greenhouse gas emissions from soil to
the atmosphere, it is important to:
 Change agricultural practices and
 Restore soils of degraded land to perennial vegetation cover.
F. Biodiversity Conservation
♠ The most abundant group of organisms in soil are bacteria.
♠ One gram of soil can contain up to 109 bacterial cells, constituting up to
104 species.
♠ Bacteria can benefit plant growth directly by stimulating root branching
and root hair development.

♠ Indirectly, it also plays an important role in dispersing of pathogens.
♠ Bacteria also regulate:
 Biogeochemical cycling,
 Influence atmospheric chemistry and climate
♠ This is processed through the production and consumption of trace
gases and degrade organic contaminants in soil.
♠ Eukaryotes are also abundant in soil.
♠ One gram of soil can also contain > 100 million of fungal hyphae.

♠ Although some fungi are pathogenic to plants, their hyphae entangle
soil & play an important role in soil aggregation & plant nutrient
use.
♠ 10 – 100 thousands of protozoa can also be found in a gram of soil
& their feeding on bacteria and fungi stimulates nutrient turnover.
♠ Nematodes can be the most numerous of all animals in the soil and
occupy all consumer trophic levels as:
 Bacteria feeders,
 Fungi feeders,
 Root herbivores,

 Predators and
 Omnivores
♠ This feeding system is contributing to the great complexity of soil
food webs.
8.3 Techniques of Soil Fertility Restoration
♠ There are three basic strategies of restoring soil quality:
1. Minimizing losses from the pedosphere or soil solum
♠ This is applied through soil erosion management.

Techniques of Soil Fertility Restoration ……
♠ This is because accelerate soil erosion depletes the Soil Organic
Carbon (SOC) pool and nutrient reserves.
2. Creating a positive soil C budget, while enhancing biodiversity
♠ This is related to soil fertility improvement by enhancing agro-
biodiversity.
♠ Soil biota are important to soil fertility and reduce risks of
degradation and desertification.
♠ Indeed, soil biota comprise a major component of global terrestrial
biodiversity and perform critical roles in key ecosystem functions.

Example
 Biomass decomposition,
 Nutrient cycling,
 Moderating CO2 in the atmosphere,
 Creating disease suppressive soils etc.
♠ Improving activity and species diversity of soil fauna and flora
(micro, meso and macro) is therefore essential to restore and
improve soil fertility and reducing risks of soil degradation.

3. Soil restorative farming/planting systems
♠ Farming/planting systems like:
 Rotations,
 Soil fertility management,
 Erosion control,
 Grazing or stocking rate,
 Water management
♠ These affect the type, rate and severity of soil degradation by
altering the SOC pool, structural morphology and other properties.

CHAPTER NINE
9. RESTORING WILDLIFE
9.1. Current Threat to Wildlife in Ethiopia
♠ The current mass extinction of wildlife entirely relies on human
being’s day to day activities as indicate below:
1) Human Settlement and Encroachment
♠ The inhabitant where wildlife existed is also the home or resource
base for many people at the proximate.
♠ As an integral part of protected area, human beings are both
contributor for conservational and source of problems to wildlife.

Current Threat to Wildlife in Ethiopia ……
♠ National parks in Africa in general and Ethiopia in particular exist to
conserve animals.
♠ This neglecting the lands and focusing only on animals leads most
of the National Parks of Ethiopia under continuous degrading from
human influences.
e.g., (1) Encroachment in/around the Semien Mountain National
Park.
 Increasing pressure due to continuous expanding human
settlements.
 Increasing demands for farming and grazing land.

E.g., (2) Degradation and destruction in Abijata-Shalla Lakes
National Park and
E.g., (3) Livestock grazing and the growing pressure of the local
communities in search of resources in Awash National Park.
2) Habitat Degradation and Fragmentation
♠ Habitat destruction is the mechanisms by which the natural habitat
where wildlife existed is deteriorated functionally and unable to
support the species found there.
♠ Landscape modification and habitat fragmentation are key drivers of
global species loss.

3) Introduction of Invasive Species
♠ Species introduction in to new environment can adversely cause
wildlife loss on native and ecologically adapted species.
♠ Capacity of reproduction, adaptation to the environmental conditions
and their interactions with surrounding can cause invasive species
make the most threats to wildlife.
♠ In such a way, the invasive species competing with native species for
feed, space and shelters.

4) Poaching and Illegal Wildlife Trafficking
♠ One of the fastest growing forbidden trades worldwide is illegal
wildlife trafficking.
♠ During the different governmental regimes of Ethiopia, illegal
hunting is forbidden in principle.
♠ But, due to several factors, wildlife is at declining state from both
threats such as illicit trade and poaching.
♠ Ethiopia is considered as both the source and transits for wildlife
and their products trafficking in the horn of Africa.

♠ Ethiopia is focusing on electronic devices and other goods, the customs
authority neglects checking for wild animals’ products.
♠ Illicit trafficking of wild animal and their body part are unnoticed in the
country.
♠ For instance, due to illegal hunting,
 Grevy’s zebra population in Ethiopia is declined by 93% over a 23
years period (1,600 to 110 from 1980 to 2003)
 Elephants are declined by 90.5% in the country.
 About 8 species of wild fauna were hunted in Chebera Churchura NP.
 Gumuz society highly depends on hunting of rodent species.

5) Climate Change
♠ Climate change has created potential threats to global biodiversity.
♠ Species may respond to the change either through modification,
move or die.
♠ To date, the major consequences of climate change are:
 Alter ecosystem and landscapes,
 Change in species life history,
 Conflicts between human and wildlife,
 Wild land fires,

 Wildlife disease,
 Invasive species and pest’s infestations.
6) Emerging Infectious Disease
♠ Infectious disease is another factor to threat wildlife.
♠ For instance, an outbreak caused by rabies and canine distemper
virus in the world’s rarest canid, the endangered Ethiopian wolf
(Canis simensis) is reported by different authors.

9.2. Techniques of Wildlife Restoration
♠ Wildlife restoration is most probably successful through habitat
conservation.
♠ Basic restoration techniques of wildlife are as mentioned below:
1) Protection by law
♠ Laws should be enacted to protect wildlife.
♠ E.g., the Ethiopian law for wildlife conservation came into force in
2008 as the Ethiopian Wildlife Conservation Authority (EWCA).
2) Establishment of Protected Area
♠ It is essential to establish wildlife sanctuaries, national parks and
biosphere reserves to protect wildlife.

Techniques of Wildlife Restoration …..
♠ These places provide ideal condition for wildlife.
3) Restoration of Original Habitat
♠ Restoration of original habitat to be built in the deforested areas.
4) Better Living Condition
♠ The animals are to be encouraged to life under the cover of thick
grass or bushes and trees.
5) Educating Common People
♠ Common people to be educated for the restoration and protection of
wildlife.
♠ This is the most effective method of preserving wildlife.

Techniques of Wildlife Restoration …..
6) Training of Wildlife Management Body
♠ Training of wildlife forest officers, wildlife ecologists, is essential
for restoration of wildlife.
9.3. Restoration Strategies
♠ The strategies developed by the Conservation Biological Diversity
(CBD) are as follows:
i. All efforts to be made to restore threatened species.
ii. All endangered species should be protected
iii. Wildlife must be protected both in natural habitat & artificial
habitats by establishing zoological & botanical gardens or parks.

Restoration Strategies…..
iv. Varieties of useful food crops, plants, animals and microbes should
be preserved for national and international breeding programs.
v. The wild plant and animals should be conserved as a gene bank for
the later.
vi. The habitats of the animals should be guarded and well protected.
vii. A protected area to be established to preserve the habitat or
migratory or wide-ranging animal species.
viii.Unique ecosystem should be conserved on top priority basis.
ix. Ecosystem to be determined for exploited species during
productive periods.

Restoration Strategies…..
♠ International trade and commerce to be prohibited in the areas of
wild animals and plants.
CHAPTER TEN
10. SOCIO-ECONOMIC ASPECTS OF RESTORATION
♠ Restoration of degraded ecosystem has direct or indirect importance
in social, economic and ecological aspects.
10.1 Economic Value of Ecosystem Restoration
♠ Restoration of degraded ecosystem provides total economic value
(TEV) which is composed of use values and non-use values.

Economic Value of Ecosystem Restoration ….
A. Use Value
♠ This involves some interaction with resource either directly or
indirectly.
i. Direct Use Value: It involves human interaction with the ecosystem
itself rather than via the services it provides.
♠ It may be consumptive or extractive use, such as fisheries, timber
etc. or,
♠ It may be non-consumptive, as with some recreational and
educational activities.

ii. Indirect Use Value: Derives from services provided by the
ecosystem.
♠ This might, for example include:
 Removal of nutrients,
 Providing clean water to those downstream,
 Prevention of downstream flooding and diseases and
 Provision of information.

B. Non-Use Value
♠ This is associated with benefits derived simply from the knowledge
that the ecosystem is maintained.
♠ It is not associated with any use of the resource or tangible benefit
derived from it, although users of a resource might also attribute
non-use value to it.
♠ It can be split in to three basic components:
i. Existence Value
♠ Derived simply from the satisfaction of the knowing that ecosystems
continue to exist, whether or not this might also benefit others.

ii. Bequest Value
♠ Associated with the knowledge that ecosystems and their services
will be passed on to descendants to maintain the opportunity for
them to enjoy it in the future.
iii. Altruistic Value
♠ Derived from knowing that contemporaries can enjoy the goods and
services ecosystems provide.
♠ Finally, another category not immediately associated with the initial
distinction between use values and non-use value includes:

Option Value
♠ An individual derives benefit from ensuring that ecosystem services
will be available for his or her own use in the future.
♠ It is a form of use value although it can be regarded as a form of
insurance to provide for possible future use.
♠ It is often associated with the potential of genetic information
inherent in biodiversity to be used for research,
e.g., pharmaceuticals.

10.2 Ecological Values of Ecosystem Restoration
♠ Restoration of degraded ecosystem have been grouped in to five
categories broadly based on ecological functions.
1) Purification and Detoxification Function
♠ This includes:
 Filtration,
 Purification and detoxification of air, water and soils.
♠ For instance, natural vegetation, especially woodlands and forests
are acted as a filter removing particulate matter arising from the
combustion of fossil fuels from the air.

Ecological Values of Ecosystem Restoration….
♠ Restored soils and particularly forest soils also serve as effective
filters.
♠ Reduce the chance of organic materials and chemicals to reach
water or purify it before reaching streams and rivers.
♠ Wetlands also perform essential function of water purification by:
 Removing nitrogen and phosphorous from agricultural runoff,
 Preventing eutrophication of streams and rivers.
 Remove or transform toxins that would otherwise contaminate
habitats.

2) Cycling Process
♠ Restored ecosystem plays crucial role in process of:
 Nutrient cycling,
 Nitrogen fixation,
 Carbon sequestration,
 Soil formation etc.
♠ For instance, vegetation plays an essential role in removing one of
the main greenhouse gases, CO2 from the atmosphere.
♠ Nutrient cycling (nitrogen fixation & breakdown of soil organic
carbon) provides an important economic input to agriculture.

♠ Soil formation processes (breakdown & release of minerals from
rock & the accumulation of animal & plant organic matter) is an
important economic input to agriculture.
3) Regulation and Stabilisation Functions
♠ These may include:
 Pest and disease control,
 Climate regulation,
 Mitigation of storms and floods,
 Erosion control,
 Regulation of rainfall and water supply.

♠ For instance, biologically rich ecosystems consist of numerous
organisms that interact with each other in complex ways.
♠ The outcome of these complex interactions is that pests and diseases
are naturally controlled, thereby minimizing the risk of outbreaks.
♠ Natural pest control reduces dependence on chemical pesticides.
♠ Chemical pesticides are in turn:
 Costly, and
 If used repeatedly, can contaminate water and soils and
 Encourage pests to develop resistance.

♠ Vegetation plays an important role in mitigation of floods and
erosion control.
♠ The role of vegetation in this case is:
 Intercepts rainfall and reduces the force with which it impacts
the soil surface,
 Binds the soil surface preventing its loss, and
 Slow water flows into streams and rivers.
♠ Wetlands temporarily store excessive water flows, which moderate
flood impacts on downstream environments.

4) Habitat Provision
♠ Restored ecosystem provides refuge for animals and plants,
storehouse for genetic materials.
♠ On other hand, it provides habitat for wild plant and animal species,
both resident and migratory.
♠ Biodiversity found in restored ecosystem represents a genetic and
biochemical library
♠ This underpins the flexibility and potential of much agricultural and
pharmaceutical development.

5) Regeneration and Production Functions
♠ This refers to the biotic productivity of natural ecosystems and the
ability of these systems to regenerate through the conversion of
light, energy and nutrients into biomass.
♠ Also included in this function are pollination and seed dispersal.
♠ The resulting broad diversity of carbohydrate structures provides
many ecosystem goods including:
 Food,
 Raw materials and
 Energy resources.

♠ An huge number of bees, beetles, moths, birds, bats and other
animals are the agents of pollen transfer from one plant to another, a
crucial step in fertilization and seed production.
♠ Pollination services represent enormous benefits for humans, as
approximately one-third of the world’s food crops rely on natural
pollinator services (Chivian, 2003).
♠ Many plants are dependent for germination on seed dispersal by
particular species of mammals, birds, insects or fish etc.

10.3. Social Values of Ecosystem Restoration
♠ Restoration of degraded ecosystems also provide human well-being.
♠ These may include:
 Aesthetic,
 Spiritual,
 Educational and
 Recreational services.
♠ The followings are some basic social services of intact ecosystem.

Social Values of Ecosystem Restoration ….
A. Security
♠ This includes:
 Personal safety
 Secure resource access
 Security from disasters
B. Basic Materials for good life
♠ This includes:
 Adequate livelihoods
 Sufficient nutritious
 Food

 Shelter
 Access to goods
C. Health
 Strength
 Feeling well
 Access to clean air and water


D. Good Social Relations
♠ This includes:
 Social cohesion
 Mutual respect
 Ability to help others

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