The devil is in the detail: the importance of understanding intraspecific responses to tropical deforestation

It is generally assumed that individuals and communities of a species will all react in the same manner to environmental change, with no presence of intraspecific variation. This is at the basis of the indicator species concept, and has long been used for Red Lists (Carignan and Villard, 2002; Rodrigues et al., 2006). However, a recent study from the Atlantic Forest in Brazil found intraspecific variation in response to deforestation across a variety of bird species (Orme et al., 2019), with distance to range edge driving this variability.

Populations of species were generally negatively affected by deforestation when present at the edge of their range (Orme et al., 2019). Contrastindly, populations of the same species at the centre of their range were often either positively affected by deforestation, or were not affected by deforestation (Orme et al., 2019). The drivers of the aforementioned patterns is not yet understood, but discerning these is paramount for conservation planning and policy making.

This project looks to understand the roles of the below mechanisms in understanding intraspecific variation in response to deforestation:

Climatic suitability (Pérez-Tris et al., 2000)
Species interactions at the community level (Angelini et al., 2016)
Drift (Hubbell, 2001)

It is expected that individuals and populations of species will be less sensitive to habitat loss if:

They are sampled in areas of high climatic suitability; with these areas shifting with climate change.
They have weak interactions with other species in the community, which will reduce the impact of competition, which is expected to increase with habitat loss. Similarly, facultative mutualistic species are expected to be more resilient than obligate mutualistic species; which may rely on species that are more sensitive to habitat loss.
Their local population was already declining as a result of demographic drift.

The above hypotheses will be tested using a range of models that will be used in conjunction with a pre-existing database of species responses to habitat loss; new data will also be added to the database.
Climatic suitability will be tested using GIS and species distribution modelling to assess current and future climate suitability. Species interactions and drift will be assessed using the Tangled Nature Model (TaNa) (Christensen et al., 2002).

The project has clear conservation importance and may inform future conservation policy, restoration, and decision making as a direct result of its findings.