Tristan Nuñez Finishing Talk

Animal movement in a changing world

Today, my dear neighbor and guinea pig sitter Tristan gave a talk at our Wildlife and Conservation Seminar at ESPM. I took notes and I am posting them here.

A finishing talk: That is how we mark the end in the graduate program at ESPM. Let’s honor Tristan!!!

Animals: move biomass and seeds around, alter nutrient cycles, pollinate. With warming they have to move away to find their niches (e.g., colder places).

How do animals ‘cross roads’ of climate change and of alterations in landscape. —> Human alterations of the environment. ???

I. Animal movements shape environments:

Example: Hippos graze at night on land. During the day they hang out in the water to stay cool and poop (Pennisi 2015 in Science). They connect land and water ecosystems. Webcam at They tagged hippos and studied where they are grazing, resting and moving around in space. GPS. Grazing, Resting, Transit. Taking that map, they modeled biomass transfer. Hippos remove biomass during grazing but add it again during pooping. Use GPS technology to measure how poop is moved around. Could be applied to cows and grazing in California landscapes. Places of resting and pooping are hotspots of biomass decomposition (i.e., nitrogen rich).

II. With changing environment animals move to more suitable habitats:

International agencies (banks and private) encourage Africa to do more land use and use irrigation system to produce food (crops). Species distribution models often ignore hydrology. Tristan addressed the following questions: Would the inclusion of hydrology improve distribution models? Does it change how we model species distributions? What are the effects of the conversion from rain-fed system to irrigated system?

Models including hydrology performed better than atmospheric models. What is an atmospheric model? I don’t know. Key finding: If you include hydrology into the model there are much fewer suitable areas! If you model how Africa is going to look like in 2070, including hydrology in the model, you almost don’t see any change in suitability of habitats for hippos. However, if you now also account for irrigation change due to an increase in agriculture, there is an 68% loss of suitable habitats. Take home messages: Including hydrology improves distribution models, projections differ between atmospheric and hydrological model, and land use will affect suitable habitat for animals. Don’t ignore hydrology when modeling species distributions even if you are working on terrestrial animals.

III. How do climate niches move through time:

40% of mammals are unable to keep pace with climate change. Temperature has been increasing during the last 100 years, however, there is a lot of variation in the rate of increase. For the last part of his dissertation, Tristan compared different biomes and how they move through time.

Here he showed a R simulation that shows how deserts moved through time in the western USA. Now animals need to be able to follow their niches. I think Tristan is not yet finished with this chapter.


How do animals shape the environment. Link movement metrics and human footprint. Help land managers by predicting which climate changes and landscape alterations are coming in the near future. Be able to react to it!

If you want to read more about hippos and their ecoystems check this out!

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