Why is biodiversity data-deficiency an ongoing conservation dilemma in Africa?

Amphibian diversity across three adjacent ecosystems in Área de Conservación Guanacaste, Costa Rica

Amphibians are the most threatened species-rich vertebrate group, with species extinctions and population declines occurring globally, even in protected and seemingly pristine habitats. These 'enigmatic declines' are generated by climate change and infectious diseases. However, the consequences of these declines are undocumented as no baseline ecological data exists for most affected areas. Like other neotropical countries, Costa Rica, including Área de Conservación Guanacaste (ACG) in north-western Costa Rica, experienced rapid amphibian population declines and apparent extinctions during the past three decades. To delineate amphibian diversity patterns within ACG, a large-scale comparison of multiple sites and habitats was conducted. Distance and time constrained visual encounter surveys characterised species richness at five sites-Murciélago (dry forest), Santa Rosa (dry forest), Maritza (mid-elevation dry-rain forest intersect), San Gerardo (rainforest) and Cacao (cloud forest). Furthermore, species-richness patterns for Cacao were compared with historic data from 1987-8, before amphibians declined in the area. Rainforests had the highest species richness, with triple the species of their dry forest counterparts. A decline of 45% (20 to 11 species) in amphibian species richness was encountered when comparing historic and contemporary data for Cacao. Conservation efforts sometimes focus on increasing the resilience of protected areas, by increasing their range of ecosystems. In this sense ACG is unique containing many tropical ecosystems compressed in a small geographic space, all protected and recognised as a UNESCO world heritage site. It thus provides an extraordinary platform to understand changes, past and present, and the resilience of tropical ecosystems and assemblages, or lack thereof, to climate change.

Monitoring biodiversity loss in rapidly changing Afrotropical ecosystems: an emerging imperative for governance and research

Africa is experiencing extensive biodiversity loss due to rapid changes in the environment, where natural resources constitute the main instrument for socioeconomic development and a mainstay source of livelihoods for an increasing population. Lack of data and information deficiency on biodiversity, but also budget constraints and insufficient financial and technical capacity, impede sound policy design and effective implementation of conservation and management measures. The problem is further exacerbated by the lack of harmonized indicators and databases to assess conservation needs and monitor biodiversity losses. We review challenges with biodiversity data (availability, quality, usability and database access) as a key limiting factor that impacts funding and governance. We also evaluate the drivers of both ecosystems change and biodiversity loss as a central piece of knowledge to develop and implement effective policies. While the continent focuses more on the latter, we argue that the two are complementary in shaping restoration and management solutions. We thus underscore the importance of establishing monitoring programmes focusing on biodiversity-ecosystem linkages in order to inform evidence-based decisions in ecosystem conservation and restoration in Africa. This article is part of the theme issue 'Detecting and attributing the causes of biodiversity change: needs, gaps and solutions'.

A temporospatial assessment of environmental quality in urbanizing Ethiopia

Global environmental quality has been negatively affected by urbanization, particularly vulnerable in the Sub-Saharan Africa. Therefore, understanding the underlying mechanism and driving forces for the change of environmental quality with urbanization process is essential to improve the environmental sustainability. In this study, the compounded night light index (CNLI) and remote sensing ecological index (RSEI) were used respectively to evaluate the urbanization level and environmental quality in Ethiopia from 2010 to 2020. On this basis, a temporospatial assessment framework was proposed, followed by methods of coupling coordination degree, spatial autocorrelation, elasticity, and decomposition. The results showed that 63 out of 690 woredas experienced environmental deterioration. Socioeconomic effect, carbon intensity, and climate change were decomposed as drivers to environmental quality, with socioeconomic effects contributing >68% of environmental improvement, while carbon intensity and climate change were responsible for >51% and >58% of environmental deterioration from 2010 values. Continuous increase in impervious surfaces resulted in a six-fold increase in surface runoff, which raised the flooding risk in sub areas and rural landscapes. This demands reforms of climate strategies and proper livestock management.

Monitoring the spatial spillover effects of urbanization on water, built-up land and ecological footprints in sub-Saharan Africa

Despite the considerable attention given to the environmental implications of urbanization, evidence on the role of urbanization in the ongoing biodiversity loss lacks from an African perspective. In this perspective, we explore the threats urbanization poses on biodiversity with a focus on water, land, and the overall ecosystems across 28 sub-Saharan African (SSA) countries over the period 2000-2017. Specifically, we employ water, land, and ecological footprints as metrics to characterize human-induced pressures on biodiversity. Unlike previous studies, we demonstrate that urbanization displays heterogeneous effects on footprint indicators, and the consideration of a single footprint item may underestimate the impact of urbanization on biodiversity loss. The results show that urbanization contributes to the expansion of human-induced pressures on water and built-up landscape. Furthermore, there is evidence that being surrounded by highly urbanized countries increases the per capita water and built-up land footprints. These spatial spillover effects of urbanization should be considered when establishing pathways to conservation policies.

WP, Sterkhova VV, Kusamba C, Rödel M, Penner J, Peterson AT, Brown RM. Rivers, not refugia, drove diversification in arboreal, sub-Saharan African snakes

The relative roles of rivers versus refugia in shaping the high levels of species diversity in tropical rainforests have been widely debated for decades. Only recently has it become possible to take an integrative approach to test predictions derived from these hypotheses using genomic sequencing and paleo-species distribution modeling. Herein, we tested the predictions of the classic river, refuge, and river-refuge hypotheses on diversification in the arboreal sub-Saharan African snake genus Toxicodryas. We used dated phylogeographic inferences, population clustering analyses, demographic model selection, and paleo-distribution modeling to conduct a phylogenomic and historical demographic analysis of this genus. Our results revealed significant population genetic structure within both Toxicodryas species, corresponding geographically to river barriers and divergence times from the mid-Miocene to Pliocene. Our demographic analyses supported the interpretation that rivers are indications of strong barriers to gene flow among populations since their divergence. Additionally, we found no support for a major contraction of suitable habitat during the last glacial maximum, allowing us to reject both the refuge and river-refuge hypotheses in favor of the river-barrier hypothesis. Based on conservative interpretations of our species delimitation analyses with the Sanger and ddRAD data sets, two new cryptic species are identified from east-central Africa. This study highlights the complexity of diversification dynamics in the African tropics and the advantages of integrative approaches to studying speciation in tropical regions.

Land Use Changes Threaten Bird Taxonomic and Functional Diversity Across the Mediterranean Basin: A Spatial Analysis to Prioritize Monitoring for Conservation

Land use changes rank among the highest threats to biodiversity, but assessment of their ecological impact is impaired by data paucity in vast regions of the world. For birds, land use changes may mean habitat loss or fragmentation, changes in resource availability, and disruption of biotic interactions or dispersal pathways. As a result, avian population sizes and assemblage diversity decline in areas subjected to urbanization, agricultural intensification, and land abandonment worldwide. This threat is especially sensitive in hotspots such as the Mediterranean basin, where avifaunas of several biogeographic origins meet, encompassing numerous endemic taxa, and ecological specialists with low resilience to habitat modifications. Here, we correlated several facets of bird taxonomic and functional diversity to a fine-grained land-use change classification, in order to identify priority areas in need for enforced protocoled bird sampling in a conservation prospect. For this, we computed the species richness, functional richness, originality and specificity of 211 bird assemblages based on bird extent-of-occurrence data for 279 species and 10 ecological traits. We used a spatialized regression model to correlate bird diversity patterns with bioclimatic gradients and land use change between 1992 and 2018, assessed from an unsupervised clustering on 2 km resolution data. We showed that species-rich bird assemblages are subjected to agricultural intensification, while functionally diverse assemblages are mainly undergoing desertification and land abandonment. Unfortunately, most of these changes occur in areas where protocoled bird surveys with sufficient spatial and temporal resolution are lacking. In light of these results, we urge for the setting of bird monitoring programs targeted mainly on parts of North-Africa and the Levant, in order to allow a region-level evaluation of the threat posed by recent land use changes on the exceptional avifaunistic diversity of the basin. Fostering such regional-scale evaluations of congruences between human threats and centers of diversity is a necessary preliminary step for a pragmatic response to data deficiencies and ultimately setting appropriate responses to avoid the collapse of avian assemblages.

Estimating occupancy of Chinese pangolin (Manis pentadactyla) in a protected and non-protected area of Nepal

Chinese pangolin is the world's most heavily trafficked small mammal for luxury food and traditional medicine. Although their populations are declining worldwide, it is difficult to monitor their population status because of its rarity and nocturnal behavior. We used site occupancy (presence/absence) sampling of pangolin sign (i.e., active burrows) in a protected (Gaurishankar Conservation Area) and non-protected area (Ramechhap District) of central Nepal with multiple environmental covariates to understand factors that may influence occupancy of Chinese pangolin. The average Chinese pangolin occupancy and detection probabilities were Ψ ^  ± SE = 0.77 ± 0.08; p ^  ± SE = 0.27 ± 0.05, respectively. The detection probabilities of Chinese pangolin were higher in PA ( p ^  ± SE = 0.33 ± 0.03) than compared to non-PA ( p ^  ± SE = 0.25 ± 0.04). The most important covariates for Chinese pangolin detectability were red soil (97%), food source (97.6%), distance to road (97.9%), and protected area (97%) and with respect to occupancy was elevation (97.9%). We recommended use of remote cameras and potentially GPS collar surveys to further investigate habitat use and site occupancy at regular intervals to provide more reliable conservation assessments.