Influence of time and flood on diurnal mammal diversity and story level use in Igapó forest in the Peruvian Amazon.

Rainforests support the highest biodiversity on Earth but are one of the most threatened ecosystems due to forest destruction and predicted effects of climate change. Mammals are an important component of rainforest ecosystems, and mammal diversity cannot be explained by forest type alone, but also by considering vertical stratification of the forest. We conducted surveys during a wet year and a dry year to estimate diversity of diurnal mammals that inhabit seasonally flooded forest in the Peruvian Amazon. We considered the vertical stratification of the forest to assess whether diversity varied by story level, and estimated alpha, beta, and gamma diversity. Mammal diversity did not differ between wet and dry years, although species richness was marginally higher in the wet year and evenness slightly low in both years. Mammal diversity differed by story level between years, but was the highest in the canopy in each year. Alpha diversity was higher in the dry year compared to the wet, and beta and gamma diversity were higher in the wet compared to the dry year. During the wet and dry year, the frequency of sightings of species was influenced by time of day and varied by story level. Protection of continuous, mature forests with large canopies has important conservation implications as these areas most likely protect the greatest diversity of mammals, while also providing shelter and food for other taxa.