The effect of single biome occupancy on the estimation of biome shifts and the detection of biome conservatism

Abstract

Biome conservatism is often regarded as common in diversifying lineages, based on the detection of low biome shift rates or high phylogenetic signal. However, many studies testing biome conservatism utilise a single-biome-per-species approach, which may influence the detection of biome conservatism. Meta-analyses show that biome shift rates are significantly lower (less than a tenth), when single biome occupancy approaches are adopted. Using New Zealand plant lineages, estimated biome shifts were also significantly lower (14–67% fewer biome shifts) when analysed under the assumption of a single biome per species. Although a single biome approach consistently resulted in lower biome shifts, it detected fewer instances of biome conservatism. A third of clades (3 out of 9) changed status in biome conservatism tests between single and multiple biome occupancy approaches, with more instances of significant biome conservatism when using a multiple biome occupancy approach. A single biome approach may change the likelihood of finding biome conservatism because it assumes biome specialisation within species, falsely recognises some biome shift types and fails to include other biome shift types. Our results indicate that the degree of biome fidelity assumed has a strong influence on analyses assessing biome shift rates, and biome conservatism testing. We advocate analyses that allow species to occupy multiple biomes.

Tracking the xeric biomes of South America: The spatiotemporal diversification of Mandacaru cactus

“…The split of SDTF nuclei in many operational units in the regionalized analysis should have obscured the clear ancestral affinities of genus Cereus by SDTF, such as detected in the azonal analysis (Figure 2). Indeed, the number of bioregionalization and oversplit of operational categories seems to be a source of bias in biogeographical reconstruction (Dale et al, 2021; Ferrari, 2018).…”

Pioneering polyploids: the impact of whole-genome duplication on biome shifting in New Zealand Coprosma (Rubiaceae) and Veronica (Plantaginaceae)

“…NZ contains three major biomes, based on vegetation structure and function [49]: forest, open and alpine [50,51]. Forest covered most of NZ throughout the Cenozoic before the uplift of the Southern Alps in the Pliocene–Pleistocene [52].…”