Impact of invasive species on native species

1. ETHIOPIAN BIODIVERSITY INSTITUTE
Impact of invasion: A case study on the ecological and socio-
economic impact of Lantana camara (L.) in Gursum woreda,
eastern Hararghe, Ethiopia .
By
Yeneayehu Fenetahu
Harar Biodiversity Center
Feb/2017
Dessie, Ethiopia
1

2. Presentation Out line
.Introduction
.Methods
.Result and and discussion
.Summary
. Recommendation
2

3. Introduction
Alien species:- a species that has been intentionally
or unintentionally introduced to a location, area, or
region where it does not occur naturally (Prieur-
R.;2000).
The deliberate or accidental introduction of non-
indigenous species to new habitats has become an
increasingly important aspect of global
environmental change and can cause important
economic, environmental and social losses
(Goulson D. ; (2004).
3

4. Cont….
 Invasive species are broadly defined as those species that are not
native to an area and that may displace or otherwise adversely
affect on:-
 Native plant and animal species
Ecosystems
Habitats
Economic
Environment
Human and animal health (IUCN ;2004).
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5. Cont…
Invasion is defined as the whole process from the
arrival of a new species into a community, its
establishment and maintenance in that community,
to its further spread into neighboring communities
(Prieur-R.;2000).
It is considered as the second most widespread
threat to global biodiversity next to habitat
destruction (Sharma et al; 2005).
They are widely distributed in all kinds of
ecosystems and include all categories of living
organisms i.e., plants, animals and Microorganisms.
5

6. Cont…
Globally, the extent of damage caused by invasive
species has been estimated to be £1.5 trillion per
year, close to 5% of global GDP (IBC ;2009).
In developing countries, where agriculture accounts
for a higher proportion of GDP, the negative impact
of invasive species on food security and economic
performance can be even greater which cause
poverty (Manchester SJ, Bullock JM .;2000).
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7. Cont…
The major invasive spices found in eastern part of
Ethiopia are Parthenium hysterophorus, Prosopis
juliflora, Lantana camara , Striga and Acacia
species were considered as emerging issues for the
country (Hailu et al.;2004).
Lantana camara (L.) is a major invader of forests,
pasture, agricultural lands and otherlands tyeps
throughout in Ethiopia (Dobhal, P.K., 2010).
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8. Cont…
Due to its strong:-
 allelopathic properties,
aggressiveness and
its dense impenetrable thorny thickets, Lantana
camara has the potential to interrupt the health and
regeneration process of other species by decreasing:-
 germination,
growth of seedlings and
 biomass production which in turn increases
mortality and decline of plant species, pasture
and crops (Catherine L. and Russell E.; 2005).
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9. Cont…
Ranked among the 100 worlds worst invasive alien
species (Day et al ,;2003).
It is a native to Central and South
America (Spies JJ and Duplessis H.; 1987).
It was introduced to Ethiopia as an
ornamental plant due to its beautiful
aromatic flowers (Binggeli P and Desalegn
D.;2002).
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10. Cont…
Presently, it has spread almost all over the country,
but still it is not much perceived as a chronic
environmental problem, in most eastern parts of
Ethiopia, such as Oromia and Somali regions .
 Currently, there is little information available on
spatial distribution of Lantana camara invasion and
its potential geographic spread on the study area.
It has covered almost all part of both the range lands
and agricultural lands of the study area, and highly
spreading and destroying the native biodiversity,
converting in to non-useable land. 10

11. Cont…
Since there is no important ecological investigation,
which is done to either indicate the status or the
extent of the weeds’ distribution and its economic as
well as ecological disadvantages in the study area
we need to do this pilot study as an indication.
11

12. Cont…
 Therefore, the goal of this study was :-
 To carry out an ecological investigation on the
distribution, invasion impact on different land uses
and associated plant species of L. camara and
 Assessing the perception of the local community
regarding its impacts on the biodiversity of Gursum
woreda.
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13. 2. Methods
2.1. Site Description
 The study was conducted in Gursum woreda, eastern Hararghe
Zone of Eastern Ethiopia.
 It is located at about 562 km southeast of Addis Ababa.
 Geographically, the study area is located between 9o 4’ - 9o 2’ N
latitude and 42o 20’ - 42o 32’ E longitude.
 Its elevation ranges between 1345 m -1950 m a.s.l.
 The mean annual temperature is about 20.2°C, ranging from a
mean minimum of 12.8°C to mean maximum of 29.4°C.
 The mean annual rainfall is 740.6 mm /year.
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14. Cont…
2.2.Data collection methods
 Both primary and secondary data sources were used.
Primary data were generated from preliminary survey,
field work and the responses of the local people and
agricultural experts who are involved directly or
indirectly with the problems of the weed.
Questionnaire, interview and group discussion were
used as the primary data collecting instruments.
Secondary data were obtained from Gursum woreda
master plan, published materials including books,
journals, research articles and census reports.
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15. Cont…
2.2.1.Field data collection
 Done by afield survey and
group discussion with the
residents of Gursum woreda
and technical staff.
 Used to collect base line information, observe vegetation distribution ,
to asses how much the L. camara covered both the range land and
agricultural lands of the society and to determine how much the
indigenous plant spices were dominated by the lanatan plant in all
ecosystem types.
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16. Cont…
2.2.2.Socio economic survey
 This was done to assess the perception and awareness of the local
people towards the species.
 The data was collected through semi-structured questionnaires and
participatory rural appraisal (PRA) interview (Martin GJ;1995).
 A total of 60 households, 50 people from local residents who have
faced problems against Lantana invasion and 10 people from agro-
forestry, woreda agricultural biro and natural and Tourism management
experts of the area were selected to be representative using purposive
sampling technique.
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17. Cont…
2.3.Data analysis:-
All data were analyzed by using Excel databases.
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18. 3. Result and Discussion
. The result of the study showed that the area was
locally dominated by L. camara.
This is due to natural vegetation that was found on
the range land and agricultural lands was
intensively deforested as a result of illegal cutting
of trees for construction, firewood and expansion of
farmlands.
This creates more access or open spaces for the fast
invasion of Lantana, cores-ponding with the
colonizing nature of the species where disturbances
are very common (Stock D.; 2005). 18

19. Cont…
3.1.Distribution of L. camara on different land uses
 The distribution of L. camara in all land uses or its mean
frequency was found to be almost similar.
 Although the abundance of Lantana towards the range land
(RL) was to some extent greater than its density towards the
cultivated or disturbed site.
 The presence of enough nutrients and the absence of shade
effect on the open and/or disturbed sites, greatly favor L.
camara to flourish and be widely distributed (Gentle and
Duggin ; 1998). 19

20. Cont…
our current finding indicated that the relative
abundance and invasion pattern of L. camara
showed a very severe rate and become a serious
fodder problem to the society practicing mixed
farming due to the modification of the habitats and
the overall ecosystem of the area.
And also there is still a controversy between the
community perception about its economic and
ecological value and the perception were present in
the ff. table.
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21. Cont…
• Table 1. Economical and ecological use values of L. camara.
 From the above table we can understand that Since L.camara
has a very negative effect on both economic and ecological
aspect there are also some benefit that provided for the
community as we got from our respondents. 21
Economic benefits Respondent’
s f (%)
Ecological benefits R e s p o n d e n t s f (%)
Source of fodder & nectar
Hedge (live & dead)
Fire wood
Medicinal value
Ornamental
Construction
10 (16.67)
21(35)
12(20)
23(38.33)
15(25)
11(18.33)
Combat desertification
Decrease soil erosion
Reduce wind speed
Shelter for wild life
Shade tree
32(53.33)
50 ( 8 3.33 )
29 ( 48 . 3 3 )
15( 2 5 )
6 ( 10 )

22. Cont…
3.2.Socio-economic and ecological impact
Table 2. Adverse impacts of L. camara.
 From the above table we can understand that L.camara has great
impact on all type of biodiversity resources and mainly grasses and
plant diversity respectively.
 And also it has –ve impact on agricultural and wood lands and on
animal health.
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Adverse Impacts Respondents f (%)
Decrease woodlands and farm lands
Injure and poison animals
Discourage growth of grasses under its canopy
Decrease crop productivity
Decrease plant diversity
50(83.33)
35 (58.33)
58 (96.66)
20 (33.33)
51 (85)

23. Cont…
3.3.People perception and attitude against the impact of L. camara.
 From this table we can understand that about 86.66% of
the local people (farmers and agro pastoralists) have
negative attitude towards the species and they are highly
supportive for its total removal.
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Perception Respondents (%)
Disadvantage
Advantage
Should be completely removed (agreed)
Should proper management adopted
(disagreed)
52 (86.66)
6 (10)
53 (88.33)
19 (31.66)
Table 3. People perception and attitude against the impact of L. camara.

24. Cont…
 while some of the community including governmental
employees (Natural resources experts and agroforestry
experts) did not support its complete eradication, and have
mixed attitude towards the species.
 They elaborated their reasons in that the plant has its own
advantage for example; such species are ecologically
successful and important in conserving genetic resources in
the environment by conserving soli erosion.
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25. Cont…
• 3.4. Management and control Mechanisms
 Even if no action is taken yet by the regional government to
control its invasion, the community is aware of the
problem, and has substantial interest to control and manage
the plant.
• Table 4. Methods used to control invasion of L. camara in the study area.
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Methods Respondents f (%)
Physically
Mechanical (Thinning and pruning)
Biological
Chemical
Burning
52 (86.67)
8 (13.33)
-
-
-

26. Cont…
 From the above table we try to understand that most of the
local people (86.67%) have tried to use only physical
methods (hand grubbing, uprooting, and cutting).
 These physical and mechanical (stickraking, bulldozing,
ploughing) techniques are in fact effective and mainly
suitable for medium sized infestations thinning and pruning
methods of control were also frequently used, especially
following the street of the place in the study area.
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27. 4. Summury
L.camara (L.), a highly aggressive exotic
environmental weed in the study area and has
significant adverse effects on biodiversity.
 This study was demonstrated that L. camara impact
negatively on native vegetation structure and
composition.
 The effects on native vegetation are direct, through
smothering and allelopathic means, and indirect
through changes in soil properties.
The study indicates that L. camara has adapted in
almost all land use types ( highly abundant in
grassland, due to absence of shade effect).
27

28. Cont…
Most of the community have the knowledge and
perception about the –ve impact of L. Camara.
 Physical methods (hand grubbing, uprooting, and
cutting) is the most usable and effective control
methods by the local community in the study area.
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29. 5.Recommendation
Based on our results, tools proposed by the
respondents and the researchers for the long term
and sustainable control of Lantana we try to
recommend the following:-
: First of all, the dilemma on the benefits and adverse
impact of L. camara could be solved by enhancing the
profits through and improving/implementing all
proper management options beyond the only physical
and mechanical options which are currently applied in
control mechanism of the weed.
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30. Cont…
The principles underpinning for strategic control need
collective action including all levels of governments,
NGOs and community groups.
 Creation of community awareness with regarding the
negative impacts of lantana’s invasion should be
given high attention.
Thinning and pruning of the plant should be adopted
before flowering or seed producing seasons so as to
reduce its seed dispersal capacities ( timing).
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31. Cont…
Finally, our results suggest a long-term study would
provide a much more detailed understanding about
the impact of L. camara invasion in the area (like
including modeling and mapping) invasion risk
potential that will result much more comprehensive
information about the whole biodiversity status of
the area and indirect effect on aquatic ecosystem
biodiversity also.
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