Rainforest Fauna in the Anthropocene: an integrated approach to understanding impacts of climate and land use change (RAINFAUNA)

The world's rainforests are incredible reservoirs of biodiversity, holding over 60% of the world's animal species and 67% of all tree species. Conserving this remarkable richness is fundamental for the planet's biological integrity. Yet, it is also under threat from a range of human pressures, such as deforestation, the disturbance of the remaining forests by fires or selective logging, as well as climate change that can exacerbate other threats. These threats are prevalent in the world's largest tropical forests, the Amazon. For example, one third of the Amazon has already been cut down or disturbed by forest fires and selective logging. The climate has also changed markedly in the past 40 years, with some regions facing increased temperatures of 2.5 degrees Celsius and marked reductions in rainfall in the dry season.

Give the scale and intensity of these changes, it is imperative that we understand how they are affecting the Amazon's diversity. To date, this has been carried out by using satellites and large-scale plot networks to assess changes in carbon stored by trees or the species composition of the forest. We have much less information on rainforest animals, which are not visible from space or airplanes, and are mobile and hard even for humans to detect on the ground. The absence of large-scale and standardised information on rainforest animals means we do not know how human impacts are affecting them at large scales.

Our RAINFAUNA project aims to resolves this knowledge gap by using new technologies and methods to make the first Amazon-wide assessment of the density of populations of birds and invertebrates (insects and arthropods). For birds, we focus on the antbirds, a group of understorey species that are emblematic of rainforest fauna. For invertebrates, we focus on species living in the leaf-litter and topsoil. These two groups provide important information for conservation and ecology. Birds are the best-known faunal group, and estimating their densities will allow us to determine population sizes of species for the first time. Understanding invertebrate activities and diversity provides insights into the important functional roles they carry out in the forests, from decomposition of leaves to the mixing of the topsoil.

We will use the forest microclimate to understand animal responses to climate change and forest disturbance. The temperature and humidity of the understorey and leaf litter are key to understanding tropical forest fauna, as they describe the conditions experienced by species. We will use sampling to explore this link between microclimate and fauna, using automated recording units to assess tropical fauna at 180 sites. We will also develop our microclimate model so it can map forest temperature and humidity across the basin. This will allow us to understand how the density of birds and activities of insect changes over space. Crucially, we can also explore how microclimate - and therefore the fauna - will change in the future under different scenarios of climate change and forest disturbance.