In Gorongosa National Park, Mozambique, civil war ravaged wildlife populations between 1977-1994. They were hunted by soldiers and civilians alike for meat and money; ivory from elephants, for example, was traded for weapons. Large mammals took a particularly hard hit. Predators like hyenas, wild dogs, leopards and jackals disappeared completely, and lions were knocked back to fewer than 30 animals. Herbivores suffered, too -- elephants dropped from 2500 to 200 and hippos from 3500 to 300. By the mid-1990s, though the park was brimming with beautiful habitat, it was empty of wildlife.
Since the early 2000s, a partnership between the Mozambican government and the U.S.-based Gregory C. Carr Foundation has been working to change that. The Gorongosa Restoration Project is one of the most ambitious restoration efforts ever undertaken. By improving anti-poaching enforcement and reintroducing species such as zebra and buffalo, park managers have managed to increase wildlife populations dramatically. Now, in fact, the biomass of large herbivores such as elephants and antelope is almost the same as it was before the war. But, they haven't returned in the same proportions -- while species such as buffalo are still only at a fraction of their former numbers, one antelope, the waterbuck (Kobus ellipsiprymnus), is doing particularly well. In fact, they're almost ten times more abundant than they were before the war -- while there were only 3,500 of then fifty years ago, there are now more than 34,000!
In my PhD work at Princeton University, I'm trying to understand why waterbuck are winning, and what that change means for the other animals and for the plants in this ecosystem. Right now, I'm working on two main projects to try and get to the bottom of the waterbuck mystery:
1. Herbivore exclosures. How are waterbuck affecting vegetation communities in Gorongosa? I've built six exclosures, or areas that have been fenced to keep animals out, to see how vegetation communities change when waterbuck can't eat the plants.
2. Dietary and movement ecology. What are waterbuck and other ungulates eating in Gorongosa, and how does that correspond with the way they move across the landscape? Might waterbuck be outcompeting other herbivore species and preventing them from recovering? I've collected almost 300 poop samples from waterbuck, buffalo, and other herbivores in Gorongosa. I'll use DNA metabarcoding to figure out what they've been eating. Also, with the help of the National Geographic Crittercam team, I put GPS collars on waterbuck and buffalo this year. The collars were also fitted with Crittercams, or small cameras that dangle from the animal's neck and take videos. That helps us to keep an eye on their behavior, including their choice of plants to eat.