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Temperature‐associated decreases in demographic rates of Afrotropical bird species over 30 years

Citation

Neate‐Clegg, Montague H. C.; Stanley, Thomas R.; Şekercioğlu, Çağan H.; Newmark, William D. (2021), Temperature‐associated decreases in demographic rates of Afrotropical bird species over 30 years, Dryad, Dataset, https://doi.org/10.5061/dryad.1c59zw3v6

Abstract

Tropical mountains harbor globally significant levels of biodiversity and endemism. Climate change threatens many tropical montane species, yet little research has assessed the effects of climate change on the demographic rates of tropical species, particularly in the Afrotropics. Here, we report on the demographic rates of 21 Afrotropical bird species over 30 years in montane forests in Tanzania. We used mark-recapture analyses to model rates of population growth, recruitment, and apparent survival as functions of annual mean temperature and annual precipitation. For over one-half of focal species, decreasing population growth rates were associated with increasing temperature. Due to the trend in temperature over time, we substituted a time covariate for the temperature covariate in top-ranked population growth rate models. Temperature was a better explanatory covariate than time for 6 of the 12 species, or 29% of all focal species. Population growth rates were also lower for species found further below their elevational midpoint and for smaller-bodied species. Changes in population growth rates were more closely tied to changes in recruitment than to changes in apparent survival. There were no consistent associations between demographic rates and precipitation. This study demonstrates temperature-associated demographic impacts for 6 (29%) of 21 focal species in an Afrotropical understory bird community and highlights the need to incorporate the impacts of climate change on demographic rates into conservation planning across the tropics.

Methods

See the published paper for full details on methods. Over 30 years (1987-2016) understory forest birds were caught in mist nets and banded in two forest blocks in the Usambara Mountains of Tanzania. We provide the capture histories for 21 focal understory bird species in the East and West Usambara Mountains. There is a text file per species, and each file contains the capture histories of each uniquely-banded individual. There is also a column for the banding location: "East" or "West". The file name is a species code; for full species names see Table 1.

Funding

JRS Biodiversity Foundation, Award: 60708_TAWIRI