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17th Annual Sahelo-Saharan Interest Group Meeting
2 days of talks on biodiversity conservation in the Sahara and in the Sa...
Assessing	the	impact	of	overgrazing	on	the	habitat						
structure	and	food	availability	of	the	African													
Houba...
Overgrazing	can	have	a	devastating	effect	on	
arid	ecosystems!	
Moderately	grazed	steppe	in	Uzbekistan Extremely	over-graz...
The	African	houbara (Chlamydotis undulata)
Considered	vulnerable	by	the	IUCN	(2017)
Main	threats	considered	to	be	hunting	...
Study	site	locations
Large	fenced	areas	allowing	for	a	clear	“grazed”	and	“ungrazed”	
comparisons
Missour - 2.915	km2 area	exclosed for	21	year...
Examining	impacts	of	overgrazing	on	houbara in	the	context	of	habitat	structure	
variability	and	food	resource	availabilit...
- Arthropod	trapping	conducted	exclusively	at	Missour in	two	years	(2002	&	2012)
- 16	pitfall	traps	established	inside	and...
Analysis	focussed	on:
- Vegetation	density
- Invertebrate	abundance
- Invertebrate	and	plant	diversity
- Invertebrate	and	...
Results	– density	and	abundance
- With	one	exception,	vegetation	density	always	higher	at	‘inside’	fence	sites	
(all	Mann-...
Results	– Plant	diversity
- Rarefaction	curves	and	non-parametric	richness	estimators	suggest	plant	species	diversity
actu...
Results	– Arthropod	diversity
- Rarefaction	curves	and	non-parametric	richness	estimators	suggest	Tenebrionidae and	ant
di...
Results	– Community	dissimilarity
Community	structure	always	changed	significantly	between	“inside		and	“outside”
sites	(a...
Discussion	and	conclusions
Results	suggest	that	overgrazing	in	Eastern	Morocco	does	not	have	a	
catastrophic	impact	on	Hou...
Next	stage	– initiating	long-term	habitat	survey	
protocols	across	a	spatially	extensive	area
- Permanent	study	squares	se...
This	next	survey	will	allow	the	exploration	of	many
more	in-depth	research	questions
Knowledge	of	carrying	capacities.
Bet...
THANK YOU FOR
Listening!
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Assessing the impact of overgrazing on the habitat structure and food availability of the African Houbara Bustard

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Presented during the 17h Annual Sahelo-Saharan Interest Group Meeting organized by the NGO Sahara Conservation Fund in Senegal, from 4 to 6 May 2017. The Sahara Conservation Fund (SCF) gathers every year about a hundred people who are interested in the field of Sahelo-Saharan species conservation.

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Assessing the impact of overgrazing on the habitat structure and food availability of the African Houbara Bustard

  1. 1. 17th Annual Sahelo-Saharan Interest Group Meeting 2 days of talks on biodiversity conservation in the Sahara and in the Sahel Assessing the impact of overgrazing on the habitat structure and food availability of the African Houbara Bustard Yves HINGRAT, Research Manager – Reneco for Wildlife Preservation Thomas MARTIN, Researcher – Reneco for Wildlife Preservation May 4 – 6, 2017
  2. 2. Assessing the impact of overgrazing on the habitat structure and food availability of the African Houbara Bustard Tom Martin & Yves Hingrat Reneco for Wildlife Preservation
  3. 3. Overgrazing can have a devastating effect on arid ecosystems! Moderately grazed steppe in Uzbekistan Extremely over-grazed steppe in Eastern Morocco Ecosystem-scale impacts of overgrazing are generally well-studied, but little research exists on its impact on specific threatened species within the Sahelo-Saharan zone.
  4. 4. The African houbara (Chlamydotis undulata) Considered vulnerable by the IUCN (2017) Main threats considered to be hunting and habitat destruction and degradation. However, this last point remains unproved empirically! We set out to test this in the context of our Eastern Morocco study area.
  5. 5. Study site locations
  6. 6. Large fenced areas allowing for a clear “grazed” and “ungrazed” comparisons Missour - 2.915 km2 area exclosed for 21 years Enjil - 10.604 km2 area exclosed for 13 years
  7. 7. Examining impacts of overgrazing on houbara in the context of habitat structure variability and food resource availability - Two variables known to be linked to the demographics of the Houbara. - Habitat structure examined using point intercept method. - Five 40x40m sample plots inside each exclosed area, and five 40x40m sample plots outside – these plots surveyed every spring between 2008-2016. - A series of 20m transects in each sample plot. - All species encountered on transects also identified for food resources analyses.
  8. 8. - Arthropod trapping conducted exclusively at Missour in two years (2002 & 2012) - 16 pitfall traps established inside and 16 pitfall traps outside the fenced area (± 700m) - Checked weekly. - Post-trapping sampling focuses on Tenebrionidae beetles and ants (based on Bourass 2012). - All identified to a species level via collaborations with specialists. - Number of individuals and dry mass of each sampling category noted.
  9. 9. Analysis focussed on: - Vegetation density - Invertebrate abundance - Invertebrate and plant diversity - Invertebrate and plant community structure
  10. 10. Results – density and abundance - With one exception, vegetation density always higher at ‘inside’ fence sites (all Mann-Whitney P = <0.05) - No difference in Tenebrionidae abundance in either year or any season (all Mann-Whitney P = <0.05) - No difference in overall ant abundance in either year (both Mann-Whitney P = <0.05). However it was consistently higher in spring (both Mann-Whitney P = <0.05) and in one year (2012) in Autumn.
  11. 11. Results – Plant diversity - Rarefaction curves and non-parametric richness estimators suggest plant species diversity actually increases outside fenced areas (except in the unusual climatic conditions experienced in Missour in 2016)
  12. 12. Results – Arthropod diversity - Rarefaction curves and non-parametric richness estimators suggest Tenebrionidae and ant diversity does not change substantially between ‘inside’ and ‘outside’ sites (except Tenebrionidae in 2012). Tenebrionidae Ants 2002 2012
  13. 13. Results – Community dissimilarity Community structure always changed significantly between “inside and “outside” sites (all Mantel test P = <0.05). Community dissimilarity analyses indicates that some plant and arthropod groups are more abundant in overgrazed study sites (eg. Lycium intricatum and Cataglyphis ruba.) Other plant and arthropod groups are more abundant in ungrazed study sites (eg. Salsola sp., Messor foreli, and Blaps sp.)
  14. 14. Discussion and conclusions Results suggest that overgrazing in Eastern Morocco does not have a catastrophic impact on Houbara habitat suitability, but we cannot say it has no impact. Overgrazing significantly influences vegetation density, but Houbara is not a species inhabiting densely vegetated grasslands! Arthropod food availability aggregated annually does not vary, but ants are less abundant at key times of the year (e.g. spring) and certain important species are less abundant in overgrazed areas. Results also cannot yet be related to other demographic parameters (breeding, display etc). More research necessary to determine full impacts of habitat degradation on Houbara.
  15. 15. Next stage – initiating long-term habitat survey protocols across a spatially extensive area - Permanent study squares set up throughout Morocco (and UAE, Uzbekistan and Kazakhstan). - 5x5 km2 squares spanning a variety of habitats, altitudes, disturbance levels etc. - Habitat structure, botanical, and invertebrate abundance/mass surveys at each. - Supported by remotely-sensed weather and vegetation cover indices. - Long-term surveys to take into account seasonal variability. - Can be directly correlated with houbara demographic data.
  16. 16. This next survey will allow the exploration of many more in-depth research questions Knowledge of carrying capacities. Better knowledge of key species threats (habitat degradation vs hunting vs climate change) Knowledge of key conservation areas Predicting new areas of good Houbara habitat More on this in the near future!
  17. 17. THANK YOU FOR Listening!

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