Diversification mechanisms in Sub-Saharan Africa have long attracted research interest with varying support for either allopatric or parapatric models of speciation. However, studies have seldom been performed across the entire continent, a scale which could elucidate the relative importance of allopatric and parapatric models of divergence. To shed light on continental-scale patterns of African biogeography and diversification, we investigated the historical demography of a bird with a continent-wide distribution in Sub-Saharan Africa, the Yellow-rumped Tinkerbird, Pogoniulus bilineatus. We sampled populations from across the continent and using genomic data, assessed genetic diversity, structure, and differentiation, reconstructed the phylogeny, and performed alternative demographic model selection between neighbouring clade pairs. We uncovered substantial genetic structure and differentiation patterns which corroborated the phylogenetic topology. Structure was chiefly influenced by the arid corridor, a postulated biogeographical barrier in Sub-Saharan Africa. Moreover, peak genetic diversities coincided with postulated refugial areas while demographic reconstructions between genetic lineages supported allopatric models consistent with the Pleistocene Forest Refuge hypothesis. However, within lineages, divergence with gene flow was supported. Continent-wide patterns of diversification involve an integration of both allopatric and parapatric mechanisms, with a role for both periods of divergence in isolation and across ecological gradients. Furthermore, our study emphasises the importance of the arid corridor as a primary biogeographical feature across which diversification occurs, yet one that has hitherto received scant attention regarding its importance in avian diversification in Sub-Saharan Africa.

Animals disperse the seeds of 60-90% of trees in tropical rainforests, which are among the most structurally complex ecosystems on Earth. Here, we investigated how 3D rainforest structure influences the movements of large, frugivorous birds and resulting spatial patterns of seed dispersal. We GPS-tracked white-thighed (Bycanistes albotibialis) and black-casqued hornbills (Ceratogymna atrata) in southern Cameroon and found that both species preferred areas of greater canopy height, and white-thighed hornbill preferred areas of greater vertical complexity. In addition, 33% of the hornbills preferred areas close to canopy gaps, while 16.7% and 27.8% avoided large and small gaps, respectively. White-thighed hornbills avoided swamp habitats, while black-casqued preferred them during the hottest temperatures. We mapped spatial probabilities of seed dispersal by hornbills, showing that 3D structural attributes shape this ecological process by influencing hornbill behavior. These results provide evidence of a possible feedback loop between rainforest vegetation structure and seed dispersal by animals.

Understanding the geographic linkages among populations across the annual cycle is an essential component for understanding the ecology and evolution of migratory species and for facilitating their effective conservation. While genetic markers have been widely applied to describe migratory connections, the rapid development of new sequencing methods, such as low-coverage whole genome sequencing (lcWGS), provides new opportunities for improved estimates of migratory connectivity. Here, we use lcWGS to identify fine-scale population structure in a widespread songbird, the American Redstart (Setophaga ruticilla), and accurately assign individuals to genetically distinct breeding populations. Assignment of individuals from the nonbreeding range reveals population-specific patterns of varying migratory connectivity. By combining migratory connectivity results with demographic analysis of population abundance and trends, we consider full annual cycle conservation strategies for preserving numbers of individuals and genetic diversity. Notably, we highlight the importance of the Northern Temperate-Greater Antilles migratory population as containing the largest proportion of individuals in the species. Finally, we highlight valuable considerations for other population assignment studies aimed at using lcWGS. Our results have broad implications for improving our understanding of the ecology and evolution of migratory species through conservation genomics approaches.

Ecosystems function in a series of feedback loops that can change or maintain vegetation structure. Vegetation structure influences the ecological niche space available for animals to partition, shaping many aspects of behavior and reproduction. In turn, animals perform ecological functions that shape vegetation structure. However, most studies concerning 3D vegetation structure consider only one of these relationships. Here, we review these separate lines of research and integrate them into a single concept that describes a feedback mechanism. We also show how remote sensing and animal tracking technologies are now available at the global scale to describe feedback loops and their consequences for ecosystem functioning. An improved understanding of how animals interact with vegetation structure in feedback loops is needed to conserve ecosystems that face major disruptions in response to climate and land use change.

Central African rainforests are predicted to be disproportionately affected by future climate change. How species will cope with these changes is unclear, but rapid environmental changes will likely impose strong selection pressures. Here we examined environmental drivers of phenotypic and genomic variation in the central African puddle frog (Phrynobatrachus auritus) to identify areas of elevated environmentally-associated turnover where populations may have the greatest capacity to adapt. We also compared current and future climate models to pinpoint areas of high genomic vulnerability where allele frequencies will have to shift the most in order to keep pace with future climate change. Analyses of body size, relative leg length, and head shape suggest that seasonal aspects of temperature and precipitation significantly influence phenotypic variation, whereas geographic distance and precipitation seasonality are the most important drivers of SNP allele frequency variation. However, neither landscape barriers nor the effects of past Pleistocene refugia had any influence on genomic differentiation. Most phenotypic and genomic differentiation coincided with key ecological gradients across the forest-savanna ecotone, montane areas and a coastal to interior rainfall gradient. Areas of greatest vulnerability were found in the lower Sanaga basin and southeastern region of Cameroon. In contrast with past conservation efforts that have focused on hotspots of species richness or endemism, our findings highlight the importance of preserving environmentally heterogeneous landscapes to preserve putatively adaptive variation and ongoing evolutionary processes in the face of climate change.