AN APPROACH TO QUANTIFY PHYLOGENETIC NICHE CONSERVATISM IN RADIATIONS OF EXTINCT AND EXTANT TAXA

The fundamental niche (NF) represents the conditions in which species can survive and reproduce. Abiotic factors have major impacts on the survival and establishment of animal and plant populations across geographic space. Studying the tolerance ranges of species to these conditions informs on how species have inhabited regions with different ecological pressures, especially when these patterns are seen under a historical lens. In this study, we use phylogenetic hypotheses of radiations with different amounts of extinct taxa to assess the degree to which abiotic NF have been conserved over evolutionary timescales (e.g., fossil mollusks, modern kingfishers). We estimate the extent of phylogenetic niche conservatism (PNC) using clean occurrence records and abiotic environmental layers to obtain character matrices for time-calibrated phylogenetic trees. This approach is based on maximum likelihood ancestral character reconstructions of individual NF dimensions’ binned ranges using the R package nichevol. Our findings suggest considerable niche conservatism within each radiation, with, for instance, no changes detected in >70% of the kingfisher tree branches. We highlight the importance of testing niche conservatism within a phylogenetic framework, in contrast to niche overlap analyses, to assure comparisons between ancestor and descendant NF and avoid niche divergence overestimation. Niche stability and PNC assumptions are key for projecting niche models to different temporal scenarios, thus, quantifying PNC represents a relevant modeling step to interpret and understand the survival of lineages through major environmental changes. This work shows how change in abiotic tolerances varies across different radiations in time and space, informing on aspects of speciation processes, and having implications for macroevolutionary and conservation paleobiology studies.