Losing lemurs: Declining populations and land cover changes over space and time.

Forest loss and degradation due to land cover changes imperil biodiversity worldwide. Subtropical and tropical ecosystems experience high deforestation rates, negatively affecting species like primates. Madagascar's endemic lemurs face exceptionally high risks of population declines and extirpation. We examined how short-term land cover changes within a fragmented landscape in southeastern Madagascar impacted the density of lemur species. Using line transects, we assessed density changes in nine lemur species across five forest fragments. Diurnal surveys were conducted monthly from 2015 to 2019 on 35 transects (total effort = 1268 km). Additionally, 21 transects were surveyed nocturnally in 2015 and 2016 (total effort = 107.5 km). To quantify forest cover changes, we generated land use/land cover (LULC) maps from Sentinel-2 imagery using supervised classification for each year. For the LULC maps, we overlayed species-specific buffers around all transects and calculated the proportion of land cover classes within them. We observed declines in the annual densities of four diurnal and cathemeral lemur species between 2015 and 2019, with species-specific declines of up to 80% (Varecia variegata). While the density of two nocturnal species decreased, one increased fivefold (Cheirogaleus major) between 2015 and 2016. By 2019, Grassland was the dominant land type (50%), while Paddy Fields had the smallest coverage (1.03%). Mature Agricultural Land increased the most (63.37%), while New Agricultural Land decreased the most (-66.36%). Unexpectedly, we did not find evidence that higher forest cover supported a higher lemur population density within sampled areas, but we found support for the negative impact of degraded land cover types on three lemur species. Our study underscores the urgent need to address land-use changes and their repercussions for primate populations in tropical ecosystems. The diverse responses of lemur species to modified habitats highlight the complexity of these impacts and emphasize the importance of targeted conservation efforts.

What's on the horizon for community-based conservation? Emerging threats and opportunities.

Community-based conservation can support livelihoods and biodiversity, while reinforcing local and Indigenous values, cultures, and institutions. Its delivery can help address cross-cutting global challenges, such as climate change, conservation, poverty, and food security. Therefore, understanding trends in community-based conservation is pertinent to setting and implementing global goals. We undertook a horizon scan to prioritize 15 emerging threats and opportunities expected to impact the future effectiveness of community-based conservation. Topics relate to global biodiversity policy; human rights; shifting human geography; inclusion, diversity, equity, and access; conservation finance and income; and economic reforms. Our findings offer guidance on strengthening community-based conservation to achieve global environmental and development goals.

Prioritizing species conservation programs based on IUCN Green Status and estimates of cost-sharing potential.

Over 1 million species around the world are at risk of extinction, and conservation organizations have to decide where to invest their limited resources. Cost-effectiveness can be increased by leveraging funding opportunities and increasing collaborative partnerships to achieve shared conservation goals. We devised a structured decision-making framework to prioritize species' conservation programs based on a cost-benefit analysis that takes collaborative opportunities into account in an examination of national and global conservation return on investment. Conservation benefit is determined by modifying the novel International Union for the Conservation of Nature Green Status for Species to provide an efficient, high-level measure that is comparable among species, even with limited information and time constraints. We applied this prioritization approach to the Wilder Institute/Calgary Zoo, Canada, a nonprofit organization seeking to increase the number of species it assists with conservation translocations. We sought to identify and prioritize additional species' programs for which conservation translocation expertise and actions could make the most impact. Estimating the likelihood of cost-sharing potential enabled total program cost to be distinguished from costs specific to the organization. Comparing a benefit-to-cost ratio on different geographic scales allowed decision makers to weigh alternative options for investing in new species' programs in a transparent and effective manner. Our innovative analysis aligns with general conservation planning frameworks and can be adapted for any organization.

Priorización de los programas de conservación de especies con base en el Estatus Verde de la UICN y las estimaciones del potencial del reparto de costos Resumen Hoy en día, las organizaciones de conservación tienen que decidir en dónde invertir sus limitados recursos a la vez que más de un millón de especies están en peligro de extinción a nivel mundial. La rentabilidad de las inversiones puede incrementarse aprovechando las oportunidades de financiación y aumentando las asociaciones de colaboración para alcanzar los objetivos de conservación compartidos. Diseñamos un marco de toma de decisiones para priorizar los programas de conservación de especies con base en un análisis de costo-beneficio que considera las oportunidades de colaboración de un estudio del rendimiento de la inversión en la conservación a escala nacional y mundial. El beneficio de la conservación se determina al modificar el novedoso Estatus Verde de las Especies de la Unión Internacional para la Conservación de la Naturaleza para proporcionar una medida eficiente y de alto nivel que pueda compararse entre especies, incluso con limitaciones de información y tiempo. Aplicamos esta estrategia de priorización al Instituto Wilder/Zoológico de Calgary (Canadá), una organización sin fines de lucro que pretende aumentar el número de especies a las que ayuda con reubicaciones de conservación. Intentamos identificar y priorizar programas de especies adicionales en los que la experiencia y las acciones de reubicación para la conservación pudieran tener un mayor impacto. La estimación de la probabilidad del potencial de reparto de costos permitió distinguir el costo total del programa de los costos específicos de la organización. La comparación de la relación costo-beneficio a diferentes escalas geográficas permitió a los responsables de la toma de decisiones sopesar las opciones para invertir en nuevos programas de especies de forma transparente y eficaz. Nuestro análisis innovador se ajusta a los marcos generales de planificación de la conservación y puede adaptarse a cualquier organización.

Limited contributions of released animals from zoos to North American conservation translocations.

With the loss of biodiversity accelerating, conservation translocations such as reintroductions are becoming an increasingly common conservation tool. Conservation translocations must source individuals for release from either wild or captive-bred populations. We asked what proportion of North American conservation translocations rely on captive breeding and to what extent zoos and aquaria (hereafter zoos) fulfill captive breeding needs. We searched for mention of captive breeding and zoo involvement in all 1863 articles included in the North American Conservation Translocations database, which comprises journal articles and grey literature published before 2014 on conservation translocations in Canada, the United States, Mexico, the Caribbean, and Central America before 2014 as identified by a comprehensive literature review. Conservation translocations involved captive breeding for 162 (58%) of the 279 animal species translocated. Fifty-four zoos contributed animals for release. The 40 species of animals bred for release by zoos represented only 14% of all animal species for which conservation translocations were published and only 25% of all animal species that were bred for releases occurring in North America. Zoo contributions varied by taxon, ranging from zoo-bred animals released in 42% of amphibian conservation translocations to zero contributions for marine invertebrates. Proportional involvement of zoos in captive-breeding programs for release has increased from 1974 to 2014 (r = 0.325, p = 0.0313) as has the proportion of translocation-focused scientific papers coauthored by zoo professionals (from 0% in 1974 to 42% in 2013). Although zoos also contribute to conservation translocations through education, funding, and professional expertise, increasing the contribution of animals for release in responsible conservation translocation programs presents a future conservation need and opportunity. We especially encourage increased dialogue and planning between the zoo community, academic institutions, and governments to optimize the direct contribution zoos can make to wildlife conservation through conservation translocations.

Standardizing the evaluation of community-based conservation success.

Community-based conservation, which strives to simultaneously improve nature conservation and alleviate poverty, must provide biological and socioeconomic benefits that are linked through effective resilience mechanisms. To date, few community-based conservation initiatives have published comprehensive assessments that track performance in these elements of success. With 45% of the world's protected areas in comanagement with local communities, standardized measures to effectively evaluate the dual goals of community-based conservation are needed. We here introduce SPECCS, a user-friendly Standardized Protocol for Evaluating Community Conservation Success that incorporates an appraisal of data quality to responsibly assess progress over time or to compare effectiveness among different initiatives. We illustrate SPECCS's use by evaluating the Wechiau Community Hippo Sanctuary (WCHS) of northern Ghana 10 and 20 yr after its inception. The WCHS has the dual objective of protecting one of Ghana's few remaining hippopotamus populations while alleviating poverty in the surrounding communities through the creation of economic opportunity and infrastructure development. Results suggest stable project performance in the 10-yr (76%) and 20-yr (76%) evaluation, with an improvement in evaluation quality from 30% to 34%. The project is currently stronger in socioeconomic (performance 86%; quality 30%) than biological (60%; 32%) outcomes and in benefits (83%, 42%) than resilience (63%, 21%). Biological resilience is challenged by poor connectivity and limited project control over threats, whereas socioeconomic resilience is affected by a decision balance that continues to favor external stakeholders. SPECCS helps pinpoint strengths and weaknesses for timely adaptive management, strategic investments, and evidence-based recognition of community-based conservation successes.

Environmental conditions and herbivore biomass determine coral reef benthic community composition: implications for quantitative baselines.

Our ability to understand natural constraints on coral reef benthic communities requires quantitative assessment of the relative strengths of abiotic and biotic processes across large spatial scales. Here, we combine underwater images, visual censuses and remote sensing data for 1566 sites across 34 islands spanning the central-western Pacific Ocean, to empirically assess the relative roles of abiotic and grazing processes in determining the prevalence of calcifying organisms and fleshy algae on coral reefs. We used regression trees to identify the major predictors of benthic composition and to test whether anthropogenic stress at inhabited islands decouples natural relationships. We show that sea surface temperature, wave energy, oceanic productivity and aragonite saturation strongly influence benthic community composition; overlooking these factors may bias expectations of calcified reef states. Maintenance of grazing biomass above a relatively low threshold (~ 10-20 kg ha-1) may also prevent transitions to algal-dominated states, providing a tangible management target for rebuilding overexploited herbivore populations. Biophysical relationships did not decouple at inhabited islands, indicating that abiotic influences remain important macroscale processes, even at chronically disturbed reefs. However, spatial autocorrelation among inhabited reefs was substantial and exceeded abiotic and grazing influences, suggesting that natural constraints on reef benthos were superseded by unmeasured anthropogenic impacts. Evidence of strong abiotic influences on reef benthic communities underscores their importance in specifying quantitative targets for coral reef management and restoration that are realistic within the context of local conditions.

Climate change impacts on the conservation outlook of populations on the poleward periphery of species ranges: A case study of Canadian black-tailed prairie dogs (Cynomys ludovicianus).

Given climate change, species' climatically suitable habitats are increasingly expected to shift poleward. Some imperilled populations towards the poleward edge of their species' range might therefore conceivably benefit from climate change. Interactions between climate and population dynamics may be complex, however, with climate exerting effects both indirectly via influence over food availability and more directly, via effects on physiology and its implications for survival and reproduction. A thorough understanding of these interactions is critical for effective conservation management. We therefore examine the relationship between climate, survival and reproduction in Canadian black-tailed prairie dogs, a threatened keystone species in an imperilled ecosystem at the northern edge of the species' range. Our analyses considered 8 years of annual mark-recapture data (2007-2014) in relation to growing degree days, precipitation, drought status and winter severity, as well as year, sex, age and body mass. Survival was strongly influenced by the interaction of drought and body mass class, and winter temperature severity. Female reproductive status was associated with the interaction of growing degree days and growing season precipitation, with spring precipitation and with winter temperature severity. Results related to body mass suggested that climatic variables exerted their effects via regulation of food availability with potential linked effects of food quality, immunological and behavioural implications, and predation risk. Predictions of future increases in drought conditions in North America's grassland ecosystems have raised concerns for the outlook of Canadian black-tailed prairie dogs. Insights gained from the analyses, however, point to mitigating species management options targeted at decoupling the mechanisms by which climate exerts its negative influence. Our approach highlights the importance of understanding the interaction between climate and population dynamics in peripheral populations whose viability might ultimately determine their species' ability to track climatically suitable space.

Marine Socio-Environmental Covariates: queryable global layers of environmental and anthropogenic variables for marine ecosystem studies.

Biophysical conditions, including climate, environmental stress, and habitat availability, are key drivers of many ecological processes (e.g., community assembly and productivity) and associated ecosystem services (e.g., carbon sequestration and fishery production). Furthermore, anthropogenic impacts such as coastal development and fishing can have drastic effects on the structure and function of marine ecosystems. Scientists need to account for environmental variation and human impacts to accurately model, manage, and conserve marine ecosystems. Although there are many types of environmental data available from global remote sensing and open-source data products, some are inaccessible to potential end-users because they exist as global layers in high temporal and spatial resolutions which require considerable computational power to process. Additionally, coastal locations often suffer from missing data or data quality issues which limit the utility of some global marine products for coastal sites. Herein we present the Marine Socio-Environmental Covariates dataset for the global oceans, which consists of environmental and anthropogenic variables summarized in ecologically relevant ways. The dataset includes four sets of environmental variables related to biophysical conditions (net primary productivity models corrected for shallow-water reflectance, wave energy including sheltered-coastline corrections) and landscape context (coral reef and land cover within varying radii). We also present two sets of anthropogenic variables, human population density (within varying radii) and distance to large population center, which can serve as indicators of local human impacts. We have paired global, summarized layers available for download with an online data querying platform that allows users to extract data for specific point locations with finer control of summary statistics. In creating these global layers and online platform, we hope to make the data accessible to a wide array of end-users with the goal of advancing marine ecosystem studies.

Fishing degrades size structure of coral reef fish communities.

Fishing pressure on coral reef ecosystems has been frequently linked to reductions of large fishes and reef fish biomass. Associated impacts on overall community structure are, however, less clear. In size-structured aquatic ecosystems, fishing impacts are commonly quantified using size spectra, which describe the distribution of individual body sizes within a community. We examined the size spectra and biomass of coral reef fish communities at 38 US-affiliated Pacific islands that ranged in human presence from near pristine to human population centers. Size spectra 'steepened' steadily with increasing human population and proximity to market due to a reduction in the relative biomass of large fishes and an increase in the dominance of small fishes. Reef fish biomass was substantially lower on inhabited islands than uninhabited ones, even at inhabited islands with the lowest levels of human presence. We found that on populated islands size spectra exponents decreased (analogous to size spectra steepening) linearly with declining biomass, whereas on uninhabited islands there was no relationship. Size spectra were steeper in regions of low sea surface temperature but were insensitive to variation in other environmental and geomorphic covariates. In contrast, reef fish biomass was highly sensitive to oceanographic conditions, being influenced by both oceanic productivity and sea surface temperature. Our results suggest that community size structure may be a more robust indicator than fish biomass to increasing human presence and that size spectra are reliable indicators of exploitation impacts across regions of different fish community compositions, environmental drivers, and fisheries types. Size-based approaches that link directly to functional properties of fish communities, and are relatively insensitive to abiotic variation across biogeographic regions, offer great potential for developing our understanding of fishing impacts in coral reef ecosystems.

Global biogeography of reef fishes: a hierarchical quantitative delineation of regions.

Delineating regions is an important first step in understanding the evolution and biogeography of faunas. However, quantitative approaches are often limited at a global scale, particularly in the marine realm. Reef fishes are the most diversified group of marine fishes, and compared to most other phyla, their taxonomy and geographical distributions are relatively well known. Based on 169 checklists spread across all tropical oceans, the present work aims to quantitatively delineate biogeographical entities for reef fishes at a global scale. Four different classifications were used to account for uncertainty related to species identification and the quality of checklists. The four classifications delivered converging results, with biogeographical entities that can be hierarchically delineated into realms, regions and provinces. All classifications indicated that the Indo-Pacific has a weak internal structure, with a high similarity from east to west. In contrast, the Atlantic and the Eastern Tropical Pacific were more strongly structured, which may be related to the higher levels of endemism in these two realms. The "Coral Triangle", an area of the Indo-Pacific which contains the highest species diversity for reef fishes, was not clearly delineated by its species composition. Our results show a global concordance with recent works based upon endemism, environmental factors, expert knowledge, or their combination. Our quantitative delineation of biogeographical entities, however, tests the robustness of the results and yields easily replicated patterns. The similarity between our results and those from other phyla, such as corals, suggests that our approach may be of broad utility in describing and understanding global marine biodiversity patterns.

Re-creating missing population baselines for Pacific reef sharks.

Sharks and other large predators are scarce on most coral reefs, but studies of their historical ecology provide qualitative evidence that predators were once numerous in these ecosystems. Quantifying density of sharks in the absence of humans (baseline) is, however, hindered by a paucity of pertinent time-series data. Recently researchers have used underwater visual surveys, primarily of limited spatial extent or nonstandard design, to infer negative associations between reef shark abundance and human populations. We analyzed data from 1607 towed-diver surveys (>1 ha transects surveyed by observers towed behind a boat) conducted at 46 reefs in the central-western Pacific Ocean, reefs that included some of the world's most pristine coral reefs. Estimates of shark density from towed-diver surveys were substantially lower (<10%) than published estimates from surveys along small transects (<0.02 ha), which is not consistent with inverted biomass pyramids (predator biomass greater than prey biomass) reported by other researchers for pristine reefs. We examined the relation between the density of reef sharks observed in towed-diver surveys and human population in models that accounted for the influence of oceanic primary productivity, sea surface temperature, reef area, and reef physical complexity. We used these models to estimate the density of sharks in the absence of humans. Densities of gray reef sharks (Carcharhinus amblyrhynchos), whitetip reef sharks (Triaenodon obesus), and the group "all reef sharks" increased substantially as human population decreased and as primary productivity and minimum sea surface temperature (or reef area, which was highly correlated with temperature) increased. Simulated baseline densities of reef sharks under the absence of humans were 1.1-2.4/ha for the main Hawaiian Islands, 1.2-2.4/ha for inhabited islands of American Samoa, and 0.9-2.1/ha for inhabited islands in the Mariana Archipelago, which suggests that density of reef sharks has declined to 3-10% of baseline levels in these areas.

Integrating biodiversity distribution knowledge: toward a global map of life.

Global knowledge about the spatial distribution of species is orders of magnitude coarser in resolution than other geographically-structured environmental datasets such as topography or land cover. Yet such knowledge is crucial in deciphering ecological and evolutionary processes and in managing global change. In this review, we propose a conceptual and cyber-infrastructure framework for refining species distributional knowledge that is novel in its ability to mobilize and integrate diverse types of data such that their collective strengths overcome individual weaknesses. The ultimate aim is a public, online, quality-vetted 'Map of Life' that for every species integrates and visualizes available distributional knowledge, while also facilitating user feedback and dynamic biodiversity analyses. First milestones toward such an infrastructure have now been implemented.