My secondary nomination for the film festival was the Serengeti Rules (2019) a 84 minute documentary about several scientists in the 1960s who discover important rules of ecosystem balance through keystone species. The particular section of the movie that sparked my nomination was about Tony Sinclair studying the population boom of wildebeest after a disease was eradicated in fear of the over 1 million wildebeests over grazing the grassland and wreak havoc on the ecosystem. At the same time wild fires were being studied in the Serengeti that were decimating the tree populations which much of the life there depended upon as a habitat and food source.
The breakthrough in the research was the discovery of the connection to wildebeest population and the frequency of wildfires, They found that the wildebeest population had an inverse correlation with the number of wildfires and their intensity. They also found the population of wildebeest reached its natural limit without any concern of over grazing the grassy savanna. The scientists concluded that by grazing the long, dry, flammable grass, the Serengeti was less susceptible to wildfires. There was an increase in the amount of forest regeneration since this discovery and provide additional habitat for animals like butterflies, giraffes and elephants.
Wildebeest were discovered to be a surprising keystone species by reducing fire risks, which manages plant succussion. While the movie focuses mainly on animals as a keystone in ecosystems, they all have either an direct or indirect effect on the abundance and evenness of fauna that provides a great example of the complexity and interconnectivity of ecosystems. There does not need to be a direct interaction between organisms for them to respond to one another.
Applied Plant Ecology Winter 2020 