zebra stripe    
     
     
 



 
     
  Megan McSherry  
  Megan McSherry  
     
  Andrew S. Gersick  
  Andy Gersick  
   
   
  Jacqueline Kariithi  
     
   
  Marc Mayes  
     
  Kaia Tombak  
  Kaia Tombak  
     
  Qing Cao  
  Qing Cao  
     
   
  Ryan Herbert  
     
     
   
     
   
   
     
   
   
     
Department of Ecology and Evolutionary Biology | Princeton University

Link to 'Former Team Members'

Megan McSherry, Postdoctoral Research Associate
My research interests center around the conservation of coupled human-natural systems, with a focus on grasslands and the people and biodiversity they support. As a NatureNet Fellow, my postdoctoral research explores how different grazing management practices affect the storage or loss of carbon in grassland soils. While studies suggest that grazer effects on soil carbon are highly context-dependent, an interesting finding from my previous work showed that these effects are influenced, in part, by an interaction between the dominant grass type of the system and the level of grazing intensity imposed on it. Building off of this finding, I am comparing management strategies and grazer effects on soil carbon across two different grassland types, in northern Kenya and in the Patagonia region of Argentina, in order to hopefully provide initial evidence to determine the future potential for large scale carbon credit projects in these regions. Click here for my personal website.
 
Andrew S. Gersick, Postdoctoral Research Associate
I study the impacts of social and physical environments on the evolution of animal communication systems. In the Rubenstein Lab I will be investigating the role of multimodal signals in competitive and affiliative relationships among zebras and other equids. In my fieldwork with spotted hyenas (with Drs Dorothy Cheney, Kay Holekamp and Robert Seyfarth in the Masai Mara, Kenya), I found that long-distance “whoop” vocalizations help hyenas coordinate collective responses to threats from lions, despite a fission-fusion social system that disperses hyena clans over territories that can be up to 1000 km2. In aviary work with brown-headed cowbirds (with Dr. David White), I studied how males’ courtship strategies and courtship songs respond to changes in the social complexity of flocks and the intensity of male-male competition. Ultimately I’m interested in how the survival strategies, social structures and communication systems of different species (including humans) all shape one another over evolutionary time.
 

Jacqueline KariithiPostdoctoral Research Associate
I am an environmental scientist passionate about conservation, tourism and development issues. My research interests focus on developing strategies for reconciling livelihood patterns in protected area landscapes. The current postdoctoral research explores the linkages between cultural heritage, biodiversity conservation and their impact on livelihoods. I will be investigating the role of the connectivity of livelihoods and land use practices in relation the cultural and biophysical landscape. The study will consist of a detailed case study research on various stakeholder groups in the Mount Elgon in Western Kenya together with a comparative analysis of their land use activities such as agriculture, tourism and foraging culture. The Mount Elgon landscape serves as one of the five water towers in Kenya which faces several conflicting issues, anthropogenic pressures and ecological threats. As I investigate issues regarding integrating divergent livelihoods in a multi-functional landscape one of the key questions  to  emerge is how to sustainably manage the competing interests of communities with variable ethno-cultural compositions, different livelihood activities, limited access or ownership of natural resources. This research may help us to understand how we can sustainably manage landscapes in and around protected areas to achieve social, economic, and environmental objectives in areas where productive land uses compete with environmental and biodiversity goals.

 

Marc MayesPostdoctoral Research Associate
Marc Mayes is a Nature Conservancy NatureNet Postdoctoral Fellow, based between Princeton University and University of California-Santa Barbara (co-advisor Dr. Kelly Caylor).  His work addresses how climate, land use and ecological processes affect terrestrial carbon, nutrient, water cycles and vegetation structure, particularly in dryland ecosystems.  Marc specializes in incorporating field data with eclectic mixes of remotely sensed data, including satellite (optical, radar) and airborne (UAS/drone-based optical and thermal) platforms, to scale understanding of plot-scale processes to landscapes.  His current projects span Zambia, Tanzania, Kenya and California.  Marc’s work with Nature Conservancy advisor Dr. Anne Trainor includes mapping land cover changes with Landsat and Sentinel data across Zambia, to monitor current and inform new land-use plans that balance conservation with agricultural development goals around sensitive habitat areas such as Kafue National Park.

 
Graduate Students
 
Kaia Tombak, Graduate student.
Considering the escalating changes in climate, habitat, and ecological communities occurring at a global scale, behavioural plasticity is likely to be important for the long-term persistence of a species. Social species can adjust their group size and social structure to survive environmental changes such as fluctuating resource availability or predation risk. I study the extent of flexibility in social behaviour in a highly generalist and gregarious taxon: the equids. We know that a single equid species can endure an exceptionally wide array of environmental conditions because the ranges they occupy (or occupied until recently) are among the most extensive of all terrestrial herbivores. But how does an individual, group, or population adjust their social behaviour to cope with varying levels of rainfall, predation, competition, and human land use changes? I hope to tackle this question by studying two equids with fundamentally different social systems. My thesis work compares the flexibility in social structure across groups of Grévy’s zebra (Equus grevyi) and plains zebra (Equus burchelli) in multiple sites where they coexist. This research may help us to understand how we can manage land in and around wildlife reserves to allow a diversity of species to survive in the long term. It will also help to elucidate why some species (like the Grévy’s zebra) are endangered, while others (like the plains zebra) are faring well. Finally, my work seeks to determine how the social behaviour of a species feeds back into the ecosystem by affecting its interactions with other species, shaping its ecological niche.
 
Qing Cao, Graduate student.
I am interested in the animal behavioral ecology and community ecology in the savanna-steppe ecosystem. In particular, my current research focuses on the resource use and niche differentiation of two sympatric equids (horse-like species) in Asia, the released Przewalski’s horse (Equus ferus przewalskii) and the indigenous Asiatic wild ass (E. hemionus). The niche differentiation driven by present competition is very rare and has been difficult to observe, especially in large mammals. Reintroducing once extinct species back to its original habitat may provide a good chance to examine how its realized niches form from the interspecific competition with another species with the similar resource requirements. My colleagues and I are working in Kalamaili Nature Reserve, using automatic camera traps and satellite telemetry in combine with observations to look at: 1) what are the fundamental and realized niches of the two equids, especially in food and water use, 2) how does the competition drive their resource use patterns, and 3) what kind of niche differentiations could allow the coexistence of the two species? For more information, please contact me at qcao 'at' princeton [dot] edu.
 
Ryan Herbert, Graduate student.
I am interested in researching the behavioral ecology of wild, feral horses (Equus ferus caballus) in the Western U.S. for the sake of their conservation.  These horse populations are now at about 100,000 individuals, nearly half of which are in long-term holding facilities run by the Bureau of Land Management (BLM).  A lack of predators in the Western ranges of most horses prevents top-down control within nature, and adequate population control by the BLM (e.g., with PZP immunocontraceptives) has not been enacted.  Therefore, bottom-up controls, such as limited forage, are expected to be the main determinants of horse population sizes.  Yet, potential environmental impacts have led cattle ranchers and ecologists alike to call for strong interventions before uncontrolled horse populations continue their rapid growth.  The U.S. government is considering culling as many as 75,000 horses to reach the BLM’s appropriate management level of 25,000.  Because many assumptions of horse ecology are directing current policy, my work will attempt to quantify how correct these assumptions are.  For example, cattle and other livestock may be exerting far greater grazing pressure on fragile ecosystems.  Cattle ranchers often blame horses for overgrazing land that their animals would use, and yet horses potentially improve cattle grazing by eating undesirable plant parts.  Climate stands as another factor that may have far more influence on species composition and abundance than horse grazing.  Furthermore, we know that an extinct equid once roamed the Western U.S., so it is feasible that Western ecosystems evolved to be resilient to equid herbivory.  In addition to these considerations, I would like to study movement patterns of horses to better understand their geospatial relationships within Western ecosystems.  This work is intended to expand our knowledge of horse ecology so that policy makers may move forward with solutions best for humans, horses, and our environment.
 

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