Interview: Dr. Duncan Kimuyu Talks About The Global Reductions In Wildlife Migration


Recently, over 100 researchers from all over the world collaborated in studying the effects of humans in terrestrial mammals. Dr. Duncan Kimuyu, lecturer and researcher at Mpala Research Centre is among the scientists that contributed to this study. He has done numerous studies that have been published in various journals including Ecological Applications, The Journal of Animal Ecology and African Journal of Ecology.

From Tanzania’s Serengeti and Ngorongoro to Kenya’s Maasai Mara and back, about 1.5 Million mammals including Wildebeest, Zebra and some antelope species migrate. This migration not only attracts predators but it is also high season for tourism. Many come to witness the spectacular migration which is listed as a wonder of the world.
If there are concerns about the reduction of such movements, there’s a pressing need to take action. Dr. Duncan helps us understand better what the implications for reduced mammal movement are and what can be done.

1. Briefly tell us about the study.

Our study examines how humans are affecting movement patterns of terrestrial nonvolant mammals. Using GPS collars, we tracked movement patterns of over 800 individual mammals from 57 species. We examined how the distance moved by these animals changed depending on the local “Human Footprint Index” (a measure of the extent of built, environments, cropland, pasture land, human population density, nighttime lights, railways, roads, and navigable waterways).

2. What were the key findings?

This study illustrates how humans are causing major changes in the way wild mammals move in the landscape. Particularly, we observed a marked decrease in movement in areas with high human footprint compared to areas with low human footprint. Such restrictions on movement likely affect the animals themselves and have adverse implications on their ecological functions.

3. Were there other Kenyan scientists involved? What was the experience for you, working with so many researchers?

This study was a huge collaborative effort from 115 researchers from 99 institutions across the world. Much credit goes to the lead author, Marlee Tucker, for constituting the team and keeping everybody on board. Access to movement data for all the animals used in this study was made possible through “Movebank”, an online data repository platform created by biologists working with Martin Wikelski. Movebank enables researchers to share and compare animal movement data freely.

4. Were there other disciplines integrated?

Although the main focus of this study was spatial ecology, we drew expertise from various other disciplines.

5. Why do animals need to move?

Animals need space to roam freely. There are various reasons why the movement of animals is important. First, movement allows animals to respond to variations in availability of food and other resources within the habitat. Thus, confining animals in one area could intensify competition or even result in habitat degradation. Secondly, the movement is an important aspect of social interactions that maintain healthy populations of animals. Processes such as dispersal and migrations help minimize chances of inbreeding.

6. What does the reduced movement for mammals mean for wild populations?

The reduced movement may have adverse implications on important ecological functions. For example, it could affect the extent to which animals facilitate nutrient redistribution and seed dispersal across the landscape. You’d also expect cascading effects across food webs.

7. (A little detour from your study) In your expert opinion, does the 2nd Phase of the SGR pose a risk to the movement of animals? If it does, what are some of the measures that should be taken to counter the risks?

Infrastructural facilities such as SGR are important development projects, but they do in fact stand on the way for animals. The million-dollar question is ‘how can the adverse impacts of such development projects be mitigated?’ For the SGR, construction of wildlife passages was touted as an adequate mitigation measure. The effectiveness of these passages remains a subject of speculation.

8. What measures (Collectively and individually) should be taken to facilitate the movement of wildlife?

Our longstanding ‘fencing and policing’ approach to conserving wildlife has created islands of protected areas in a sea of human settlements. We need to recognize the fact that animal movement is an important aspect that maintains healthy populations and sustains ecological functions. Thus, our conservation efforts should embrace animal movement as a key conservation metric, and where possible, work towards increasing connectivity and animal movement across the landscape.

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