Biology subjects

Reijenga, B. R.

Publications and source records attributed to Reijenga, B. R..

4 recordsLinked to original sources

bioRxiv2024

Tetrapod species-area relationships across the Cretaceous-Paleogene mass extinction

Mass extinctions are rare but catastrophic events that profoundly disrupt biodiversity. Widelyaccepted consequences of mass extinctions, such as biodiversity loss and the appearance of temporary disaster taxa, imply that nested species-area relationships (SARs, or how biodiversity scales with area) should change dramatically across these events: specifically, both the slope (reflecting the rate of accumulation of new species with increasing area) and intercept (reflecting the density of species at local scales) of the power-law relationship should decrease. However, these hypotheses have not been tested, and the contribution of variation in the SAR to diversity dynamics in deep time has been neglected. We use fossil data to quantify nested SARs in North American terrestrial tetrapods through the Cretaceous-Paleogene (K/Pg) mass extinction (Campanian-Ypresian). SARs vary substantially through time and among groups. In the pre-extinction interval (Maastrichtian), unusually shallow SAR slopes (indicating low beta diversity or provinciality) drive low total regional diversity in dinosaurs, mammals and other tetrapods. In the immediate post-extinction interval (Danian), the explosive diversification of mammals drove high regional diversity via a large increase in SAR slope (indicating higher beta diversity or provinciality), and only a limited increase in SAR intercept (suggesting limited diversity change at small scales). This contradicts the expectation that post-extinction biotas should be regionally homogenized by the spread of disaster taxa and impoverished by diversity loss. This early post-extinction increase in SAR slope was followed in the Thanetian-Selandian ([~]4.4. myr later) by increases in the intercept, indicating that diversity dynamics at local and regional scales did not change in synchrony. These results demonstrate the importance of SARs for understanding deep-time diversity dynamics, particularly the spatial dynamics of recovery from mass extinctions.

paleontology↗

bioRxiv2024

Apparent timescaling of fossil diversification rates is caused by sampling bias

Negative scaling relationships between both speciation and extinction rates on the one hand, and the age or duration of organismal groups on the other, are pervasive, and recovered in both molecular phylogenetic and fossil time series. The agreement between molecular and fossil data hints at a universal cause, and potentially to incongruence between micro- and macroevolution. However, the existence of negative rate scaling in fossil time series has not undergone the same level of scrutiny as in molecular data. Here, we analyse the marine fossil record across the last ~538.8 Ma of the Phanerozoic to investigate the presence and strength of negative rate scaling. We find that negative rate scaling arises under commonly applied age range-based per-capita rates, which do not control for sampling bias, but are severely reduced or absent when metrics are used that do correct for sampling. We further show by simulation that even moderately-incomplete sampling of species occurrences through time may induce rate scaling. We thus conclude that there are no significant scaling relationships present in these fossil clades, and that any apparent trend is caused by sampling artefacts and taxonomic practices. If rate scaling in molecular phylogenies is genuine, the absence of such a relationship in the fossil record will provide a valuable benchmark and constraint on what processes can cause it. HighlightsO_LIStudies have found that fossil and molecular diversification rates scale with time C_LIO_LISuch rate scaling hints at a disconnect between micro- and macroevolution C_LIO_LIThese trends are absent from the fossil record when controlling for sampling biases C_LIO_LIRate scaling in general may be artefactual, or fossils could show distinct patterns C_LI

evolutionary biology↗

bioRxiv2024

Colonisation lags predict sympatric diversity in birds

Speciation is the ultimate source of biodiversity. However, because most species arise in spatial isolation (allopatry), how speciation shapes patterns of co-occurring (sympatry) species richness remains unclear. Here we examine how the history of past speciation events influences the maximum sympatric species richness attained across passerine bird clades (n = 40 families). Using a phylogenetic model, we infer that the rate at which species assemble in sympatry is extremely slow, and on average millions of years after speciation onset. As a result, having accounted for clade size, sympatric species richness varies substantially across families, being highest in small or ancient clades comprised of older species that have had more time to accumulate in sympatry. While our analysis does not test the ecological or evolutionary processes causing the slow build-up of sympatric assemblages, our results show that speciation history has left an indelible legacy on current species richness patterns.

evolutionary biology↗

bioRxiv2022

Disentangling the historical routes to community assembly in the global epicentre of biodiversity

AimThe coexistence and turnover of species along elevation gradients makes tropical mountains hotspots of biodiversity. However, understanding the historical processes through which species arising in geographic isolation (i.e. allopatry) assemble along the same mountain slope (i.e. sympatry) remains a major challenge. Multiple models have been proposed including, (1) the sorting of already elevationally divergent species, (2) the displacement of elevation upon secondary contact, potentially followed by convergence, or (3) elevational conservatism, in which ancestral elevational ranges are retained. However, the relative contribution of these processes to generating patterns of elevational overlap and turnover is unknown. LocationTropical mountains of Central- and South-America. Time periodThe last 12 myr. Major taxa studiedBirds. MethodsWe collate a dataset of 165 avian sister pairs containing estimates of phylogenetic age, geographical and regional elevational range overlap. We develop a framework based on continuous-time Markov models to infer the relative frequency of different historical pathways in explaining present day overlap and turnover of sympatric species along elevational gradients. ResultsWe show that the turnover of closely related bird species across elevation can predominantly be explained by displacement of elevation ranges upon contact (81%) rather than elevational divergence in allopatry (19%). In contrast, overlap along elevation gradients is primarily (88%) explained by conservatism of elevational ranges rather than displacement followed by elevational expansion (12%). Main conclusionsBird communities across tropical elevation gradients are assembled through a mix of processes, including the sorting, displacement and conservatism of species elevation ranges. The dominant role of conservatism in explaining co-occurrence of species on mountain slopes rejects more complex scenarios requiring displacement followed by subsequent expansion. The ability of closely related species to coexist without elevational divergence provides a direct and thus faster pathway to sympatry and may help explain the exceptional species richness of tropical mountains.

evolutionary biology↗