Biology subjects

Skeels, A.

Publications and source records attributed to Skeels, A..

4 recordsLinked to original sources

bioRxiv2026

Aridification and habitat shifts drove diversification in Australian diplodactylid geckos

Continental radiations record the long-term interplay between environmental change, ecological opportunity, and lineage diversification across large geographic scales. The gecko family Diplodactyli-dae represents one such radiation with [~]200 species distributed across Australia, New Caledonia, and Aotearoa New Zealand, occupying ecological forms ranging from burrow-dwelling desert specialists to canopy climbers, and diversifying over a [~]45 Ma history shaped by dramatic continental environ-mental change. Using [~]5000 nuclear loci, we reconstructed phylogenetic relationships and divergence times, estimated ancestral ecology and biomes using newly generated biome-through-time maps for Australia, and modeled the effects of ecological states on diversification and morphology. Crown diplodactylids originated in the mid-Eocene ([~]45 Ma), with the core Australian clade radiating in the Oligocene ([~]28 Ma), substantially younger than previous estimates. Ancestral state estimation indicated arboreal origins in mesic environments, followed by repeated transitions into open habitats and expansion into semi-arid and arid biomes. Despite moderate differences in diversification rates among ecological states, rate variation was better explained by unmeasured hidden states than by observed ecological states, suggesting that our broad ecological categorization alone does not explain diversification dynamics within this radiation. Size varies with ecological state, while tail length shows no detectable ecological association and remains phylogenetically conserved. These patterns indicate that environmental change and biome transformation were associated with ecological opportunity, coinciding with diversification through repeated habitat transitions and morphological divergence, providing a macroevolutionary framework linking environmental change, ecological expansion, and trait evolution in a continental radiation.

evolutionary biology↗

bioRxiv2026

Unexpected global biodiversity responses to climate change arise from complex adaptation, seascape, and dispersal dynamics

Global marine biodiversity peaks in the tropics and is widely projected to shift polewards under climate warming as species track thermal optima. These projections rely largely on phenomenological models that treat species responses as shifts in climate suitability and neglect fundamental eco-evolutionary dynamics. The consequences of these dynamics in fluctuating populations for global biodiversity patterns therefore remain unresolved. We addressed this deficit by integrating local adaptation, dispersal, and gene flow - mediated trait homogenisation into spatially explicit global simulations of >1,400 tropical reef fishes under climate change. Biodiversity responses departed systematically from simple poleward redistribution. Depending on the interaction between dispersal and adaptive capacity, latitudinal richness peaks widened or narrowed, shifted equatorward or poleward, or collapsed entirely. These alternative regimes emerged from threshold-dependent interactions between seascape connectivity, metapopulation trait homogenisation, and accumulating thermal stress. Critically, greater dispersal enhanced persistence only below seascape-driven connectivity thresholds; beyond which homogenisation of traits across thermally heterogeneous populations disrupted local adaptation - particularly at metapopulation peripheries - and increased extinction risk. Continuous demographic feedback further generated cumulative stress and extinction tipping dynamics absent from snapshot suitability models. Our results show that eco-evolutionary dynamics can invert or destabilise expected climate-driven redistribution patterns, indicating that projections excluding these mechanisms may systematically misestimate the magnitude and direction of global biodiversity change in a rapidly warming ocean.

ecology↗

bioRxiv2022

Non-equilibrium processes prevail in shaping species richness and functional diversity of terrestrial vertebrates in a global hotspot

AimThe effects of equilibrium and nonequilibrium processes are generally investigated using species richness on a single biological group. However, little is known about how these two classes of processes also affect trait diversity, considering multiple taxa within the same geographical template. Here, we evaluated which variables representing equilibrium (topography, climate, and primary productivity) and nonequilibrium (diversification rate and evolutionary time) processes best explain species richness and trait diversity of four clades of vertebrates within the same global hotspot. We also investigated how trait disparity has accumulated over time and whether there are congruent spatial patterns between groups. LocationAtlantic Rainforest Time periodContemporary. Major taxa studiedTerrestrial vertebrates. MethodsWe tested whether the spatial pattern of Functional Dispersion (FDis), richness, diversification rate, and evolutionary time of each group are correlated. We used a spatially explicit structural equation model to test how species richness and functional dispersion are influenced by variables representing equilibrium and nonequilibrium mechanisms. Additionally, we explored how trait disparity accumulated over time in the four groups. ResultsWe found that non-equilibrium proxies, evolutionary time and diversification rate, played a primary role in driving species richness and trait diversity, with elevation and climate variables having only an indirect effect species and trait diversity via diversification rate and evolutionary time. We found a congruent pattern of species richness among all groups, except among ectotherms. In contrast, the spatial distribution of evolutionary time was distinct for each group. Main conclusionsDespite nonequilibrium processes were more important for generating large-scale diversity patterns within the same geographical template, the interplay between evolutionary time and dispersal ability have disparately determined the assembly of communities.

ecology↗

bioRxiv2018

Spatiophylogenetic modelling of extinction risk reveals evolutionary distinctiveness and brief flowering period as risk factors in a diverse hotspot plant genus

Comparative models used to predict species threat status often combine variables measured at the species level with spatial variables, causing multiple statistical challenges, including phylogenetic and spatial non-independence. We present a novel bayesian approach for modelling threat status that simultaneously deals with both forms of non-independence and estimates their relative contribution, and we apply the approach to modelling threat status in the Australian plant genus Hakea. We find that after phylogenetic and spatial effects are accounted for, species with greater evolutionary distinctiveness and a shorter annual flowering period are more likely to be threatened. The model allows us to combine information on evolutionary history, species biology, and spatial data, to calculate latent extinction risk (potential for non-threatened species to become threatened), and estimate the most important drivers of risk for individual species. This could be of value for proactive conservation decision-making that targets species of concern before they become threatened.

ecology↗