Forest Fragmentation and its impact

1. Mr. Madhab Chandra Behera
Mizoram University, Aizawl, India

2. The word forest is derived from Latin word “Foris” means outside
FOREST: “A plant community predominately of trees and
other woody vegetation usually with a closed
canopy.”
Forest Degredation vs Fragmentation ????

3. What is Forest Fragmentation ?
Breaking of large, contiguous, forested areas into
smaller pieces of forest.
Typically these pieces are separated by agriculture,
utility corridors and other human development activity.

4. Aspects of Forest Fragmentation
Large patch of forest
ForestFragmentationProcess
Incision
Perforation
Dissection
Dissipation
Shrinkage
Attrition
1. Reduction in area
2. Mosaic residuals

5. Causes of forest Fragmentation
Natural Events-
1. Over long time frames - geological forces (continental drift)
- climate change ( glaciations, changes
in rainfall, sea level rise)
2. Over short periods - natural disturbances like forest fires,
volcanoes, earthquake, floods, landslides,
windstorms, etc.
3. Other - Mountain ridges, canyons, rivers and lakes.
Natural disturbance regime leading to forest fragmentation, create
the habitat heterogeneity and landscape diversity upon which many
species depend. Leads to speciation.

6. Causes of forest Fragmentation
Anthropogenic Actions:
 1. Developmental activities like roads, power transmission line,
Hydropower projects, dams, etc.
2. Human habitation,
3. Industrialization,
4. Agriculture
5. Deforestation, etc.
Loss of forest land in a landscape and have cumulative impact
over time. Consequential impact depends on connectivity,
management of remnant patch and the species in question.
The process is fast and continuous in nature

7. Consequences of Forest Fragmentation
FOREST FRAGMENTATION
Ecological
Demographic
Genetic

8. Ecological consequences of fragmentation
1. Change in physical environment
2. Change in biogeochemical process-Altered hydrologic regime
- Nutrient cycling
3. Reduced habitat quality
4. Changes in species composition
5. Edge effects
– type of disturbance & Its penetration to core
- Connectivity
- Abiotic edge effects (Microclimate/Ecological process change
etc)
- biological edge effects –Direct/Indirect
(litter fall & decomposition, establishment of recruits, pollen & seed
dispersal, pollination & fertilization etc.)
6. Invasion & Establishment of Alien species

9. Demographic Aspects of Fragmentation
1). EFFECTS ON PRIMATES- Reduces primate biodiversity and
alters primate demographics and behavior
2). EFFECTS ON BIRDS- negatively affect the distribution of
breeding birds, temporal rates of change in community
composition and higher rates of local extinction
3). EFFECTS ON INVERTEBRATES- vulnerable to fragmentation
and respond quite rapidly to habitat change.
4). EFFECTS ON PLANTS- elevated tree mortality, damage,
elevated wind throw and forest structural damage.
Forest fragmentation has the capacity to impact habitat
quality for more than 80% of all mammal, reptile, bird, and
amphibian species.

10. Forest fragmentation- Effects on plants:
Forest fragmentation isolates populations and affects
many ecological properties at the organism, population and
community levels
Fragmentation of plant communities increases the
proportion of edges, leading to changes in microclimate including
changes in light, temperature, and luminosity conditions, which
can lead to shifts in plant phenological patterns.
It affects species’ abundance and richness
(population demography), phenology, male and female
reproductive fitness, and it also affects the degree of
specialization versus generalization of pollination networks.

11. Forest fragmentation- Effects on plants contd.
1. Impact on Pollination:
(1) Plant density, (2) Pollinator density, and (3) Pollinator behaviour
(particularly movement).
(1) Plant density: A change in the abundance, distribution or health of plants has the
potential to influence pollination. Pollination success is related to
both the number of conspecific flowers nearby and the distance
between flowers within a patch. It influences flower advertisement,
pollen availability etc.
Ex: Pollination in pines vs tropical trees
Forest Fragmentation influence pollination
via altering three primary mechanisms:
(2) Pollinator density: Abundance and diversity of the pollinator community.
(3) Pollinator behaviour: Changes in pollinator daily movements, including foraging
extent and foraging pattern, diet selection, influences
pollination rocess

12. Forest fragmentation- Effects on plants: Pollination
Forest
Fragmentation
Xiao et al., 2015

13. Forest fragmentation- Effects on plants contd.
2. Impact on Seed Dispersal
 Forest fragmentation increases seed dispersal limitation across
the landscape.
 In plants dispersed by animals, behavior, foraging decisions, and
habitat preferences exerted by frugivores shape the spatial patterns
of seed deposition. Case study by Vovo et al., 2018. in tropical
forest of Brazil

14. Forest fragmentation- Effects on plants contd.
3. Impact on Seedling Recruitment :
Forest fragmentation jeopardizes seedling germination and
further establishment by
1. Limiting number of microsites in which seeds can
safely germinate, become established,
2. Growth limitation
3. Effects of abiotic and biotic factors etc.

15. FOREST FRAGMENTATION
Altered
Abundance
4. Impact on Species interaction:
Forest fragmentation- Effects on plants contd.

16.  At the population level, the fragmentation process reduces
population size and increases isolation.
 Population isolation, leads to change population genetic
composition, demography and mating patterns.
 Remnant populations experience increased genetic drift,
increasing mating events between related individuals
(inbreeding), and limited gene flow from surrounding
populations.
 This is expected to lead to decreasing genetic variability
and viability of forest tree species.
 The smaller the population size the greater these effects
on genetic structure.
Genetic consequences of fragmentation
As suggested by the classical theory of population genetics.

17. Genetic consequences of fragmentation:
1. Impact on gene flow:
o Gene flow is the transfer of alleles from one population to
another population through immigration of individuals.
o Gene flow is an important mechanism for transferring genetic
diversity among populations.
o Migrants change the distribution of genetic diversity within the
populations, by modifying the allele frequencies.

18. Genetic Consequences of Forest Fragmentation
A
A

20. 2. Species survival
Genetic consequences of fragmentation:
FOREST FRAGMENTATION

21. CONCLUSION
 Forest fragmentation reduces habitat size
 Impact may be +ve or –ve depending upon the
size of fragmentated patches, connectivity among
patches, management regime and species
concerned, how much population truly isolated,
how long ago the fragmentation occur, and other
factor.
 Forest fragmentation reduces genetic diversity if
there is no connectivity or gene flow.
 In cross pollinated species it increases inbreeding
and adaptability jeopardized.
 In more or less Forest fragmentation reduces
biodiversity.

22. Bibliography
1. Belay Beyene B., Beyene B., Unasho A and Derbe H. 2016. Processes
of Forest Fragmentation ant Its Impacts. Journal of Resources
Development and Management. 23:37-46
2. Mills L.S. and Tallmon D.A. 1999. The role of genetics in understanding
forest fragmentation. In: Forest Fragmentation: wildlife and
management implications. (Eds. Rochelle, J. A., L. A. Lehmann, and E.
Wisniewski). Brill Publications, Leidon, Boston, Koln. Pp-171-84
4. Kramer A.T et al. 2008. The Paradox of Forest Fragmentation Genetics.
Conservation Biology. 22(4):878-885.
5. Piotti A. 2009.The genetic consequences of habitat fragmentation: the
case of forests. 2: 75-76
6. Finger, A., Et al., Forest Fragmentation genetics: what can genetics tell
us about forest fragmentation. In: Global Forest Fragmentation(Eds.
Chris J. Kettle and Lian Pin Koh. Department of Environmental System
Science, ETH Zurich, Switzerland. Pp:50-69
7. https://www.conserve-energy-future.com/causes-effects-solutions-for
habitat-loss-and-destruction.php