Quantitative estimates of glacial refugia for chimpanzees (Pan troglodytes) since the Last Interglacial (120,000 BP)
Authors: Barratt Christopher D. , Lester Jack D. , Gratton Paolo , Onstein Renske E. , Kalan Ammie K. , McCarthy Maureen S. , Bocksberger Gaëlle , White Lauren C. , Vigilant Linda , Dieguez Paula , Abdulai Barrie , Aebischer Thierry , Agbor Anthony , Assumang Alfred K. , Bailey Emma , Bessone Mattia , Buys Bartelijntje , Carvalho Joana S. , Chancellor Rebecca , Cohen Heather , Danquah Emmanuel , Deschner Tobias , Dongmo Zacharie N. , Doumbé Osiris A. , Dupain Jef , Duvall Chris S. , Eno‐Nku Manasseh , Etoga Gilles , Galat‐Luong Anh , Garriga Rosa , Gatti Sylvain , Ghiurghi Andrea , Goedmakers Annemarie , Granjon Anne‐Céline , Hakizimana Dismas , Head Josephine , Hedwig Daniela , Herbinger Ilka , Hermans Veerle , Jones Sorrel , Junker Jessica , Kadam Parag , Kambi Mohamed , Kienast Ivonne , Kouakou Célestin Y. , N′Goran Kouamé P. , Langergraber Kevin E. , Lapuente Juan , Laudisoit Anne , Lee Kevin C. , Maisels Fiona , Mirghani Nadia , Moore Deborah , Morgan Bethan , Morgan David , Neil Emily , Nicholl Sonia , Nkembi Louis , Ntongho Anne , Orbell Christopher , Ormsby Lucy Jayne , Pacheco Liliana , Piel Alex K. , Pintea Lilian , Plumptre Andrew J. , Rundus Aaron , Sanz Crickette , Sommer Volker , Sop Tenekwetche , Stewart Fiona A. , Sunderland‐Groves Jacqueline , Tagg Nikki , Todd Angelique , Ton Els , van Schijndel Joost , VanLeeuwe Hilde , Vendras Elleni , Welsh Adam , Wenceslau José F. C. , Wessling Erin G. , Willie Jacob , Wittig Roman M. , Yoshihiro Nakashima , Yuh Yisa Ginath , Yurkiw Kyle , Boesch Christophe , Arandjelovic Mimi , Kühl Hjalmar 
Published: August 2021

Paleoclimate reconstructions have enhanced our understanding of how past climates have shaped present‐day biodiversity. We hypothesize that the geographic extent of Pleistocene forest refugia and suitable habitat fluctuated significantly in time during the late Quaternary for chimpanzees (Pan troglodytes). Using bioclimatic variables representing monthly temperature and precipitation estimates, past human population density data, and an extensive database of georeferenced presence points, we built a model of changing habitat suitability for chimpanzees at fine spatio‐temporal scales dating back to the Last Interglacial (120,000 BP). Our models cover a spatial resolution of 0.0467° (approximately 5.19 km2 grid cells) and a temporal resolution of between 1000 and 4000 years. Using our model, we mapped habitat stability over time using three approaches, comparing our modeled stability estimates to existing knowledge of Afrotropical refugia, as well as contemporary patterns of major keystone tropical food resources used by chimpanzees, figs (Moraceae), and palms (Arecacae). Results show habitat stability congruent with known glacial refugia across Africa, suggesting their extents may have been underestimated for chimpanzees, with potentially up to approximately 60,000 km2 of previously unrecognized glacial refugia. The refugia we highlight coincide with higher species richness for figs and palms. Our results provide spatio‐temporally explicit insights into the role of refugia across the chimpanzee range, forming the empirical foundation for developing and testing hypotheses about behavioral, ecological, and genetic diversity with additional data. This methodology can be applied to other species and geographic areas when sufficient data are available.