First conservation assessment of selected long-proboscid flies (<i>Moegistorhynchus </i>and <i>Prosoeca</i>, Diptera: Nemestrinidae) endemic to South Africa’s Cape region

Previous studies show that conservation actions have prevented extinctions, recovered populations, and reduced declining trends in global biodiversity. However, all studies to date have substantially underestimated the difference conservation action makes because they failed to account fully for what would have happened in the absence thereof. We undertook a scenario-based thought experiment to better quantify the effect conservation actions have had on the extinction risk of the world's 235 recognized ungulate species. We did so by comparing species' observed conservation status in 2008 with their estimated status under counterfactual scenarios in which conservation efforts ceased in 1996. We estimated that without conservation at least 148 species would have deteriorated by one International Union for Conservation of Nature (IUCN) Red List category, including 6 species that now would be listed as extinct or extinct in the wild. The overall decline in the conservation status of ungulates would have been nearly 8 times worse than observed. This trend would have been greater still if not for conservation on private lands. While some species have benefited from highly targeted interventions, such as reintroduction, most benefited collaterally from conservation such as habitat protection. We found that the difference conservation action makes to the conservation status of the world's ungulate species is likely to be higher than previously estimated. Increased, and sustained, investment could help achieve further improvements.

Protected areas (PAs) are a cornerstone of conservation efforts and now cover nearly 13% of the world's land surface, with the world's governments committed to expand this to 17%. However, as biodiversity continues to decline, the effectiveness of PAs in reducing the extinction risk of species remains largely untested. We analyzed PA coverage and trends in species' extinction risk at globally significant sites for conserving birds (10,993 Important Bird Areas, IBAs) and highly threatened vertebrates and conifers (588 Alliance for Zero Extinction sites, AZEs) (referred to collectively hereafter as ‘important sites’). Species occurring in important sites with greater PA coverage experienced smaller increases in extinction risk over recent decades: the increase was half as large for bird species with>50% of the IBAs at which they occur completely covered by PAs, and a third lower for birds, mammals and amphibians restricted to protected AZEs (compared with unprotected or partially protected sites). Globally, half of the important sites for biodiversity conservation remain unprotected (49% of IBAs, 51% of AZEs). While PA coverage of important sites has increased over time, the proportion of PA area covering important sites, as opposed to less important land, has declined (by 0.45–1.14% annually since 1950 for IBAs and 0.79–1.49% annually for AZEs). Thus, while appropriately located PAs may slow the rate at which species are driven towards extinction, recent PA network expansion has under-represented important sites. We conclude that better targeted expansion of PA networks would help to improve biodiversity trends.

Climate change has ubiquitous impacts on ecosystems and threatens biodiversity globally. One of the most recognized impacts are redistributions of species, a process which can be hindered by habitat degradation. Protected areas (PAs) have been shown to be beneficial for preserving and reallocating species occurrences under climate change. Yet, studies investigating effects of PA networks on species' range shifts under climate change remain scarce. In theory, a well-connected network of PAs should promote population persistence under climate change and habitat degradation. To study this, we evaluated the effects of PA coverage on avian communities in Finland between two study periods of 1980–1999 and 2000–2015. Climate-driven community impacts were investigated by using community temperature index (CTI). We used linear models to study the association of PA coverage and the CTI changes in southern, central and northern Finland. In northern and central Finland, higher PA coverage was associated with lower changes in CTI and 45% PA coverage in northern and 13% in central Finland corresponded with complete mitigation of CTI increase. These results indicate that higher PA coverage strongly increases community resilience to warming climate. However a similar association between PA coverage and changes in CTI was not apparent in southern Finland. The PA coverage in southern Finland was much lower than in the two other sections and thus, may be too sparse to favour community resilience against climate change. The results provide empirical evidence for the international need to rapidly expand PA networks and halt biodiversity loss.

Large conservation opportunities exist in >90% of tropic-subtropic coastal habitats adjacent to cities

Biodiversity hotspots are rich in endemic species and threatened by anthropogenic influences and, thus, considered priorities for conservation. In this study, conservation achievements in 36 global biodiversity hotspots (25 identified in 1988, 10 added in 2011, and one in 2016) were evaluated in relation to changes in human population density and protected area coverage between 1995 and 2015. Population densities were compared against 1995 global averages, and percentages of protected area coverage were compared against area-based targets outlined in Aichi target 11 of the Convention on Biological Diversity (17% by 2020) and calls for half Earth (50%). The two factors (average population density and percent protected area coverage) for each hotspot were then plotted to evaluate relative levels of threat to biodiversity conservation. Average population densities in biodiversity hotspots increased by 36% over the 20-year period, and were double the global average. The protected area target of 17% is achieved in 19 of the 36 hotspots; the 17 hotspots where this target has not been met are economically disadvantaged areas as defined by Gross Domestic Product. In 2015, there are seven fewer hotspots (22 in 1995; 15 in 2015) in the highest threat category (i.e., population density exceeding global average, and protected area coverage less than 17%). In the lowest threat category (i.e., population density below the global average, and a protected area coverage of 17% or more), there are two additional hotspots in 2015 as compared to 1995, attributable to gains in protected area. Only two hotspots achieve a target of 50% protection. Although conservation progress has been made in most global biodiversity hotspots, additional efforts are needed to slow and/or reduce population density and achieve protected area targets. Such conservation efforts are likely to require more coordinated and collaborative initiatives, attention to biodiversity objectives beyond protected areas, and support from the global community.

The establishment of baseline IUCN Red List assessments for plants is a crucial step in conservation planning. Nowhere is this more important than in biodiversity hotspots that are subject to significant anthropogenic pressures, such as Madagascar. Here, all Madagascar palm species are assessed using the IUCN Red List categories and criteria, version 3.1. Our results indicate that 83% of the 192 endemic species are threatened, nearly four times the proportion estimated for plants globally and exceeding estimates for all other comprehensively evaluated plant groups in Madagascar. Compared with a previous assessment in 1995, the number of Endangered and Critically Endangered species has substantially increased, due to the discovery of 28 new species since 1995, most of which are highly threatened. The conservation status of most species included in both the 1995 and the current assessments has not changed. Where change occurred, more species have moved to lower threat categories than to higher categories, because of improved knowledge of species and their distributions, rather than a decrease in extinction risk. However, some cases of genuine deterioration in conservation status were also identified. Palms in Madagascar are primarily threatened by habitat loss due to agriculture and biological resource use through direct exploitation or collateral damage. The recent extension of Madagascar’s protected area network is highly beneficial for palms, substantially increasing the number of threatened species populations included within reserves. Notably, three of the eight most important protected areas for palms are newly designated. However, 28 threatened and data deficient species are not protected by the expanded network, including some Critically Endangered species. Moreover, many species occurring in protected areas are still threatened, indicating that threatening processes persist even in reserves. Definitive implementation of the new protected areas combined with local community engagement are essential for the survival of Madagascar’s palms.

Much research has focused on identifying traits that can act as useful indicators of how habitat loss affects the extinction risk of species, and the results are mixed. We developed 2 simple, rapid-assessment models of the susceptibility of species to habitat loss. We based both on an index of range size, but one also incorporated an index of body mass and the other an index combining habitat and dietary specialization. We applied the models to samples of birds (Accipitridae and Bucerotidae) and to the lemurs of Madagascar and compared the models' classifications of risk with the IUCN's global threat status of each species. The model derived from ecological attributes was much more robust than the one derived from body mass. Ecological attributes identified threatened birds and lemurs with an average of 80% accuracy and endangered and critically endangered species with 100% accuracy and identified some species not currently listed as threatened that almost certainly warrant conservation consideration. Appropriate analysis of even fairly crude biological information can help raise early-warning flags to the relative susceptibilities of species to habitat loss and thus provide a useful and rapid technique for highlighting potential species-level conservation issues. Advantages of this approach to classifying risk include flexibility in the specialization parameters used as well as its applicability at a range of spatial scales.

Data deficiency is a substantial challenge for extinction risk assessments because incomplete data means we cannot accurately identify priority protected areas for conservation. Here, we use the International Union for Conservation of Nature (IUCN) distributions of amphibians, sharks and rays, fish, mammals, birds, and reptiles to identify hotspots of data deficient species. We found that areas with high numbers of data deficient species were not randomly distributed and did not necessarily overlap with hotspots of biodiversity, particularly in the Amazon and West Africa. Data deficiency hotspots were concentrated around tropical South America, Africa, and Southeast Asia; however, this distribution varied between taxa. Hotspots of data deficient amphibians were concentrated around the tropical Andean forests of Colombia, Peru, and Ecuador; throughout Brazil; and in the New Guinea Highlands. The tropical forests of the Congo River basin, Papua New Guinea, and the Philippines were hotspots for avian data deficiency. Data deficient chondrichthyans were concentrated in the tropical seas, particularly around the western coast of Africa, East Asia, and the tropical Americas. Indochina was identified as the primary hotspot for data deficient freshwater fish, whereas the Indo-Pacific was the primary hotspot for data deficient marine fish. Data deficient marine mammals were broadly distributed around the southern oceans, South America, Southeast Asia, and Northwest Africa. Data deficient herpetofauna were concentrated around tropical Asia, whereas tropical South America, Indonesia, and central Africa were the hotspots for data deficient terrestrial mammals. Although data deficiency reflected drivers of biodiversity more broadly (e.g., latitude), other factors were also influential, including the amount of conservation funding invested by a country and population density. Increasing evidence suggests that data deficient species are disproportionately likely to be threatened with extinction. Scientists urgently need to focus their research efforts on these data deficiency hotspots and ensure protected area networks are suitably representative and include data deficient species. Furthermore, the accuracy of status assessments needs to be ascertained, and data deficient species need to be prioritized for study to ensure they are not lost before they are identified.

Although most plant species have yet to have their extinction risk evaluated for the IUCN Red List, current knowledge of plant diversity suggests that tens of thousands (8%–38% of species) are likely to remain assessed as Data Deficient (DD). This impacts evaluations of the overall proportion of threatened species, as well as on setting appropriate priorities for biodiversity conservation. One of the principle causes of Data Deficiency is taxonomic uncertainty: data permitting an IUCN Red List assessment is often lacking, because species that are poorly known are also taxonomically uncertain. Establishing the taxonomic status of DD species thus assists in determining whether confusion over this is causing their evaluation as DD. In this paper, three separate numerical methods – hierarchical clustering, ordination and phylogenetic ordination – were applied to three independent datasets of standardized traits for plant species from China in order to identify, for each DD species, morphologically similar Non-DD species. Semi-automated analysis of morphological disparity quickly identifies which species are in need of further taxonomic research, as shared traits can indicate either potential synonymy or, otherwise, successful adaptations of distinct species to similar ecological conditions. Extinction risk assessments of morphologically and phylogenetically distinct DD species could then be informed by data on habitat preferences, geographic range or population size from Non-DD species with the most similar traits. Ultimately, determination of the morphological distance between DD species and their most similar Non-DD species, and therefore of differences in the trait space occupied by DD and Non-DD species, could be the basis of future research for improved inference of conservation priorities, and help distinct DD species with similar ecological traits as other taxonomically accepted, threatened species to be identified as being threatened themselves.

Stopping declines in biodiversity is critically important, but it is only a first step toward achieving more ambitious conservation goals. The absence of an objective and practical definition of species recovery that is applicable across taxonomic groups leads to inconsistent targets in recovery plans and frustrates reporting and maximization of conservation impact. We devised a framework for comprehensively assessing species recovery and conservation success. We propose a definition of a fully recovered species that emphasizes viability, ecological functionality, and representation; and use counterfactual approaches to quantify degree of recovery. This allowed us to calculate a set of 4 conservation metrics that demonstrate impacts of conservation efforts to date (conservation legacy); identify dependence of a species on conservation actions (conservation dependence); quantify expected gains resulting from conservation action in the medium term (conservation gain); and specify requirements to achieve maximum plausible recovery over the long term (recovery potential). These metrics can incentivize the establishment and achievement of ambitious conservation targets. We illustrate their use by applying the framework to a vertebrate, an invertebrate, and a woody and an herbaceous plant. Our approach is a preliminary framework for an International Union for Conservation of Nature (IUCN) Green List of Species, which was mandated by a resolution of IUCN members in 2012. Although there are several challenges in applying our proposed framework to a wide range of species, we believe its further development, implementation, and integration with the IUCN Red List of Threatened Species will help catalyze a positive and ambitious vision for conservation that will drive sustained conservation action.

Climate Change, Connectivity, and Conservation Success

Multifaceted patterns of protected area (PA) expansion are reviewed considering: i) the increase in PA number and coverage; ii) distribution and extent of important bird areas (IBAs); and iii) distribution and coverage of global biodiversity hotspots and the Global 200 Ecoregions that fall within the Hindu Kush-Himalayas (HKH). The analysis revealed that biodiversity conservation is a priority for the eight regional member countries of the HKH, who have established 488 PAs over the last 89 years (1918 to 2007). The eight countries sharing the HKH have committed 39% of this total geographical area to the PA network and 11% to IBAs, which is quite significant when compared to the global target of 10%. There has been an increasing trend in PA establishment over the last four decades. The PA coverage within the HKH of China alone is significant (35.5%), followed by India (1.46%) and Nepal (0.58%). When IUCN management categories are considered, the majority of PAs belong to Category V (39%), followed by Category IV (29%). Only 0.6% of PAs are managed as Category I, and, in recent years, Categories V and VI have increased. Of the total HKH geographical area, 32% is covered by four global biodiversity hotspots and 62% by the Global 200 Ecoregions. However, only 25% of the global biodiversity hotspots and 40% of the Global 200 Ecoregions are part of the PA network. There are still numerous gaps in conservation in the HKH. Coordinated and committed efforts are required to bring other critical habitats within the PA network in the HKH.

Predicting the true status of Data Deficient (DD) species is a prominent theme in recent conservation biology, but there still is much debate regarding the conservation approach that should be used for DD taxa and no definitive conclusions are yet available. We review and analyse the current data available on the conservation status of amphibians in Vietnam, with an emphasis on the DD species. We also compare Vietnamese DD frequency of occurrence with other regions of the world, examine the extent of the range of taxa divided by Red List status, and explore the protection attributes of the taxa based on their inclusion within protected areas of Vietnam. We documented that the analysis of amphibians in Southeast Asia, and especially in Vietnam, substantially agrees with patterns highlighted by previous global research, and confirms the risk that several DD species may silently go extinct without their actual risk ever being recognized. Importantly, our study showed that fine-scale analyses are essential to highlight the potential drivers of extinction risk for the DD species of amphibians. A crucial next step for conservation policies in Vietnam (and in surrounding countries) is developing and implementing species-specific studies targeted at addressing each species’ drivers of extinction and determining science-based strategies for minimizing their extinction risk.

The conservation status of the world’s reptiles

Summary Cost‐effective reduction of uncertainty in global biodiversity indicators is a central goal of conservation. Comprising a sixth of the 74 000+ species currently on the IUCN Red List, Data Deficient species contribute to considerable uncertainty in estimates of extinction risk. Estimating levels of risk in Data Deficient species will require large resources given the costs of surveys and Red List assessments. Predicting extinction risk from species traits and geographical information could provide a cheaper approach for determining the proportion of Data Deficient species at risk of extinction. We use double sampling theory to compare the cost‐effectiveness of predictive models and IUCN Red List assessments for estimating risk levels in Data Deficient terrestrial mammals, amphibians, reptiles and crayfish. For each group, we calibrate machine learning models of extinction risk on species of known conservation status and assess their cost and reliability relative to field surveys followed by Red List assessments. We show that regardless of model type used or species group examined, it is always more cost‐effective to determine the conservation status of all species with models and assess a small proportion of species with IUCN criteria (double sampling), rather than spend the same resources on field surveys and Red List assessments alone (single sampling). We estimate that surveying and re‐assessing all Data Deficient species currently listed on the IUCN Red List (12 206 species) with IUCN criteria would cost a minimum of US $323 million. Double sampling reduces the cost of determining the proportion of Data Deficient species at risk of extinction by up to 68%, because <6% of Data Deficient species would need to be surveyed and assessed with IUCN criteria. Synthesis and applications. Double sampling with models cost‐effectively estimates extinction risk levels in poorly known species and can be used to reduce the impact of uncertainty in the Red List and Red List Index. We provide recommendations for uptake by managers and a sampling planner spreadsheet. Double sampling could be applied more widely in ecology and conservation to formally compare the cost‐effectiveness of sampling methods differing in cost and reliability.