Luther studying forest fragmentation and climate change

David Luther, Assistant Professor, Biology,received funding from the National Science Foundation for: "Collaborative Research: LTREB: Forest fragmentation and climate change result in understory warming that adversely affects tropical avian biodiversity at the BDFFP." 

Luther and his collaborators posit that remnant bird communities in Amazonian forest fragments are a precursor of future bird assemblages in continuous forest due to understory forest drying from edge effects in fragments and climate change in continuous forest. Increased physiological stress and/or dietary specialization are likely determinants of avian survival and reproductive success under global climate change.  

The researchers have three objectives for this project. 

First, they aim to assess the impact of climate change as the primary driver of long-term bird declines in Amazonian continuous forest at the Biological Dynamics of Forest Fragmentation Project (BDFFP) through the inclusion of 40 years of climate and bird banding data in a series of survival models.  

Second, they plan to determine the interactive effects of climate change and fragmentation on the viability of bird populations at BDFFP through demographic modeling. More specifically researchers are assessing the impacts microclimate variation, as well as hotter and reduced rain in the dry season on survival and reproduction. 

Finally, they intend to measure how dietary and behavioral specialization of model bird species (two experiencing declines: White-necked Thrush Turdus albicollis and Scale-backed Antbird Willisornispoecilinotus, and two experiencing population growth: Wedge-billed Woodcreeper Calyptorhynchus spirurus and White-plumed Antbird Pithysalbifrons) interact with variation in understory microclimates to affect survival and reproduction.   

The researchers will measure diet using a combination of eDNA and isotopic niche analysis (from fecal samples, feathers, and toe nails) and stress using a combination of B-OH butyrate, triglyceride, and corticosterone, across seasons and between continuous and fragmented forests.  

They hold that their results will yield mechanistic insights into the role that niche specialization and understory drying play in driving demographic responses of tropical birds to forest fragmentation and climate change. 

Luther received $90,491, out of $200,000 from NSF for this project. Funding began in July 2023 and will end in late June 2025. His collaborator Jared Wolfe from Michigan Tech University will receive the other portion of the NSF funding. Luther is also collaborating with researchers at the Brazilian Institute for Amazon Research (INPA) and the Federal University of Manaus (UFAM).