Search

Secondary sympatry amongst sister lineages is strongly associated with genetic and ecological divergence. This pattern suggests that for closely related species to coexist in secondary sympatry, they must accumulate differences in traits that mediate ecological and/or reproductive isolation. Here, we characterized inter- and intraspecific divergence in three giant tree frog species whose distributions stretch across West and Central Africa. Using genome-wide single-nucleotide polymorphism data, we demonstrated that species-level divergence coincides temporally and geographically with a period of large-scale forest fragmentation during the late Pliocene. Our environmental niche models further supported a dynamic history of climatic suitability and stability, and indicated that all three species occupy distinct environmental niches. We found modest morphological differentiation amongst the species with significant divergence in tympanum diameter and male advertisement call. In addition, we confirmed that two species occur in secondary sympatry in Central Africa but found no evidence of hybridization. These patterns support the hypothesis that cycles of genetic exchange and isolation across West and Central Africa have contributed to globally significant biodiversity. Furthermore, divergence in both ecology and reproductive traits appear to have played important roles in maintaining distinct lineages. At the intraspecific level, we found that climatic refugia, precipitation gradients, marine incursions, and potentially riverine barriers generated phylogeographic structure throughout the Pleistocene and into the Holocene. Further studies examining phenotypic divergence and secondary contact amongst these geographically structured populations may demonstrate how smaller scale and more recent biogeographic barriers contribute to regional diversification., (© 2021 John Wiley & Sons Ltd.)

Despite extensive research on ecological community compositions, general patterns across large-scale environmental gradients have remained unclear. A widely used explanatory model is the stress dominance hypothesis (SDH), predicting that the relative influence of environmental filtering is greater in stressful habitats while competition is more important in benign environments. Here, we test the SDH using African squamates as a model system to facilitate general predictions on community structures amidst changing global environments. For the first time we investigate changes in functional, phylogenetic and species diversity across continental, environmental gradients within a multidimensional, phylogenetically informed approach. Results suggest that phylogenetic patterns of African squamates were likely shaped by clade-specific biogeographic histories, whereas functional structure reflects SDH predictions. We further detected significant structuring at both local and regional spatial scales, emphasizing the impact of regional-historical processes on local assemblages, and the need for broad conceptual frameworks to detect general patterns of community composition.

Frogs in the genus Amnirana (family Ranidae) are widely distributed across sub-Saharan Africa and present a model system for exploring the relationship between diversification and geography across the continent. Using multiple loci from the mitochondrial (16S) and nuclear genomes (DISP2, FICD, KIAA2013, REV3L), we generated a strongly supported species-level phylogeny that provides insights into the continental biogeography of African species of Amnirana, which form a monophyletic group within the genus. Species delimitation analyses suggest that there may be as many as seven additional species of Amnirana in Africa. The biogeographic history of Amnirana is marked by several dispersal and vicariance events, including dispersal from the Lower Guinean Forest into the Congo Basin. In addition, phylogeographic patterns within two widespread species, A. albolabris and A. galamensis, reveal undescribed cryptic diversity. Populations assigned to A. albolabris in western Africa are more closely related to A. fonensis and require recognition as a distinct species. Our analyses reveal that the Lower and Upper Guinean Forest regions served as important centers of interspecific and intraspecific diversifications for Amnirana., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Global change effects on biodiversity and human wellbeing call for improved long-term environmental data as a basis for science, policy and decision making, including increased interoperability, multifunctionality, and harmonization. Based on the example of two global initiatives, the International Long-Term Ecological Research (ILTER) network and the Group on Earth Observations Biodiversity Observation Network (GEO BON), we propose merging the frameworks behind these initiatives, namely ecosystem integrity and essential biodiversity variables, to serve as an improved guideline for future site-based long-term research and monitoring in terrestrial, freshwater and coastal ecosystems. We derive a list of specific recommendations of what and how to measure at a monitoring site and call for an integration of sites into co-located site networks across individual monitoring initiatives, and centered on ecosystems. This facilitates the generation of linked comprehensive ecosystem monitoring data, supports synergies in the use of costly infrastructures, fosters cross-initiative research and provides a template for collaboration beyond the ILTER and GEO BON communities., (Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.)

Abstract To answer questions such as whether the existing network of protected areas is sufficient, conservation needs data covering complete taxonomic groups and large geographic areas. However, most distributional data sets are either coarse, patchy and/or based solely on expert opinion which is often hard to verify. In addition, not all regions are equally well studied. For example sub-Saharan Africa remains comparatively under-sampled for most taxa, especially Central and Western Africa. However, these regions contain many threatened species, including a high diversity of highly threatened vertebrates - amphibians. To fill this knowledge gap, we extrapolated species occurrence records (n = 15,944) on a 30 arc-seconds grid for most known West African amphibian taxa (92%), using environmental niche modelling and employing relevant environmental parameters (climate, vegetation, elevation & distance to rivers). We provide, for the first time, a fine scale distribution map of amphibian alpha diversity for the entire West African region. Already known centres of high biodiversity were confirmed (e.g. south-western Ghana and south-eastern Côte d'Ivoire) and new ones were identified (e.g. northern Liberia and the borders of Liberia with Guinea and Sierra Leone). Diversity analyses focusing on unique amphibians, i.e. threatened, endemic and evolutionary distinct species', revealed that areas of high diversity also contained many high conservation-priority species. Herewith, we offer a comprehensive baseline for identifying those areas which are important for amphibian conservation for one of the most periled regions on the continent. Those areas of high diversity were only partly in accordance with previous analyses such as the hotspot definitions, the ecoregion analyses, or analyses of other taxa, highlighting the added new value of our approach. The most outstanding areas of amphibian diversity were only partly covered by the existing network of protected areas. Thus there is an urgent need to devise a regional conservation concept to protect West African amphibians from extinction. Graphical abstract Image 1 Highlights • We ask where are important areas for conservation in West Africa? • Creation of modelled fine-grained (ca. 1 km2) distributions for 92% of West African amphibians. • Invention of a novel way of stacking grids of at extent and resolution. • Several important areas in Upper Guinea forests are revealed. • There is a need for a regional conservation concept. [ABSTRACT FROM AUTHOR]

Abstract: Biodiversity is continuing to decline. This crisis has been recognised by the Convention on Biological Diversity (CBD), whose members have set ambitious targets to avert ongoing declines in the state of biodiversity by 2020. These so called “Aichi Biodiversity Targets” (ABTs) are organized around five strategic goals, with indicators showing the level of progress made towards each target. Currently, measurements of many ABT indicators are not available. The Essential Biodiversity Variable (EBV) framework, developed by the Group on Earth Observations Biodiversity Observation Network (GEO BON), attempts to form a coherent and harmonised set of observations of biodiversity. In this paper, we explore the potential role of Earth Observation (EO) as a tool to support biodiversity monitoring against the ABT and EBV frameworks. We show that EO‐based measurements are adequate for assessing progress towards 11 out of 20 ABTs. In addition, 14 of the 22 candidate EBVs have a fully or partly remotely‐sensed component and can be considered as Remote Sensing Essential Biodiversity Variables (RS‐EBVs). Those with a partial EO component require further in‐situ data and/or modelling effort to complete the EBV. While the status of biodiversity can be assessed with both fully and partly measured RS‐EBVs, assessing trends is more challenging, particularly for partly measured RS‐EBVs, as coincident time series of EO and supporting data are lacking. A synthetic pathway for developing generic biodiversity indicators using RS‐EBVs is proposed. [ABSTRACT FROM AUTHOR]

Members of the snake subfamily Aparallactinae occur in various habitats throughout sub-Saharan Africa. The monophyly of aparallactine snakes is well established, but relationships within the subfamily are poorly known. We sampled 158 individuals from six of eight aparallactine genera in sub-Saharan Africa. We employed concatenated gene-tree analyses, divergence dating approaches, and ancestral-area reconstructions to infer phylogenies and biogeographic patterns with a multi-locus data set consisting of three mitochondrial ( 16S , cyt b, and ND4 ) and two nuclear genes ( c-mos and RAG1 ). As a result, we uncover several cryptic lineages and elevate a lineage of Polemon to full species status. Diversification occurred predominantly during the Miocene, with a few speciation events occurring subsequently in the Pliocene and Pleistocene. Biogeographic analyses suggested that the Zambezian biogeographic region, comprising grasslands and woodlands, facilitated radiations, vicariance, and dispersal for many aparallactines. Moreover, the geographic distributions of many forest species were fragmented during xeric and cooler conditions, which likely led to diversification events. Biogeographic patterns of aparallactine snakes are consistent with previous studies of other sub-Saharan herpetofauna. [ABSTRACT FROM AUTHOR]