Dr Marion Valeix
During my MSc, supervised by Dr. Hervé Fritz (CNRS, France), I studied long-term trends in ungulate population abundances in Hwange National Park, Zimbabwe. I showed that the increase in the elephant population that occurred since 1986 (after elephant culling stopped) has been correlated with a decline in many ungulate populations, which called for urgent investigation of the underlying mechanisms.
Consequently, during my PhD at Paris 6 University (France), also supervised by Dr. Hervé Fritz, I focused on mechanisms through which elephants may influence other ungulate populations and I investigated two main questions: 1)- do elephants modify vegetation structure to the detriment of other ungulate species?, and 2)- do elephants prevent other ungulate species from accessing surface water in the dry season? The main result from my work was that even though some behavioural changes seem to occur for other ungulates, no direct negative effect of elephants on other ungulates could be demonstrated. My dissertation was entitled "Insights into processes structuring large herbivore communities: the role of elephants in the functioning of an African savanna" and I graduated in 2006.
In conjunction with my PhD work, I coordinated the Hwange Environmental Research Development project (HERD project), which is a collaboration project between Zimbabwe National Parks and two French research institutions (CIRAD and CNRS).
I have held a post-doctoral position at WildCRU since April 2007, in close collaboration with the LBBE (CNRS) at the University of Lyon, France. The rationale is to bring together two detailed and parallel datasets and expertise (one on ungulate ecology through the HERD project and one on lion ecology through WildCRU) to produce unique analysis of predator-prey relationships in tropical ecosystems. Because the increase in elephant-induced vegetation changes may have influenced not only the hunting success of predators, but also the vulnerability of ungulates in Hwange, investigating predator-prey relationships arguably constitutes a first and important step towards a better understanding of the Hwange ecosystem functioning.Selected Publications
Valeix M, Loveridge AJ, Davidson Z, Madzikanda H, Fritz H & Macdonald DW (2010) How key habitat features influence large terrestrial carnivore movements: waterholes and African lions in semi-arid savanna of north-western Zimbabwe. Landscape Ecology 25: 337-351.
Périquet S, Valeix M, Loveridge AJ, Madzikanda H, Macdonald DW & Fritz H (2010) "Individual vigilance of African herbivores while drinking: the role of immediate predation risk and context" Animal Behaviour 79: 665-671.
Valeix M, Loveridge AJ, Chamaillé-Jammes S, Davidson Z, Murindagomo F, Fritz H & Macdonald DW (2009) "Behavioral adjustments of African herbivores to predation risk by lions: spatiotemporal variations influence habitat use" Ecology 90: 23-30.
Valeix M, Fritz H, Loveridge AJ, Davidson Z, Hunt JE, Murindagomo F & Macdonald DW (2009) "Does the risk of encountering lions influence African herbivore behaviour at waterholes?" Behavioral Ecology and Sociobiology 63: 1483-1494.
Valeix M, Fritz H, Canévet V, Le Bel S & Madzikanda H (2009) "Do elephants prevent other African herbivores from drinking at waterholes in the dry season?" Biodiversity and Conservation 18: 569-576.
Loveridge AJ, Valeix M, Davidson Z, Murindagomo F, Fritz H & Macdonald DW (2009) "Changes in home range size of African lions in relation to pride size and prey biomass in a semi-arid savanna" accepted in Ecography 32: 953-962.
Chamaillé-Jammes S, Valeix M, Bourgarel M, Murindagomo F & Fritz H (2009) "Seasonal density estimates of common large herbivores in Hwange National Park, Zimbabwe" accepted in African Journal of Ecology 47: 804-808.
Valeix M, Fritz H, Chamaillé-Jammes S, Bourgarel M & Murindagomo F (2008) "Fluctuations in abundance of large herbivore populations: insights into the influence of dry season rainfall and elephant numbers from long-term data" Animal Conservation 11: 391-400.
Valeix M, Fritz H, Matsika R, Matsvimbo F, Madzikanda H (2008) "The role of water abundance, thermoregulation, perceived predation risk, and interference competition in water access by African herbivores" African Journal of Ecology 46: 402-410.
Chamaillé-Jammes S, Fritz H, Valeix M, Murindagomo F & Clobert J (2008) "Resource variability, aggregation and direct density dependence in an open context: the local regulation of an African elephant population" Journal of Animal Ecology 77: 135-144.
Valeix M, Chamaillé-Jammes S & Fritz H (2007) "Interference competition and temporal niche shifts: elephants and herbivore communities at waterholes" Oecologia 153: 739-748.
Valeix M, Fritz H, Dubois S, Kanengoni K, Alleaume S & Saïd S (2007) "Vegetation structure and ungulate abundance over a period of increasing elephant abundance in Hwange National Park, Zimbabwe" Journal of Tropical Ecology 23: 87-93.
Chamaillé-Jammes S, Valeix M & Fritz H (2007) "Managing heterogeneity in elephant distribution: interactions between elephant population density and surface-water availability" Journal of Applied Ecology 44: 625-633.
Chamaillé-Jammes S, Valeix M & Fritz H (2007) "Elephant management: why can't we throw out the babies with the artificial bathwater?" Diversity and Distributions 13: 663-665.
Poisbleau M, Fritz H, Valeix M, Perroi PY, Dalloyau S, Lambrechts M (2006) "Social dominance correlates and family status in wintering dark-bellied brent geese, Branta bernicla bernicla" Animal Behaviour 71: 1351-1358.
• identification of mechanisms structuring large mammal communities • functioning of African savannas • behavioural ecology of predator-prey relationships