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The Global Biodiversity Framework (GBF), signed in 2022 by Parties to the Convention on Biological Diversity, recognized the importance of area-based conservation, and its goals and targets specify the characteristics of protected and conserved areas (PCAs) that disproportionately contribute to biodiversity conservation. To achieve the GBF's target of conserving a global area of 30% by 2030, this Essay argues for recognizing these characteristics and scaling them up through the conservation of areas that are: extensive (typically larger than 5,000 km2); have interconnected PCAs (either physically or as part of a jurisdictional network, and frequently embedded in larger conservation landscapes); have high ecological integrity; and are effectively managed and equitably governed. These areas are presented as "Nature's Strongholds," illustrated by examples from the Congo and Amazon basins. Conserving Nature's Strongholds offers an approach to scale up initiatives to address global threats to biodiversity., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Robinson et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Quantitative indicators are a common means of assessing the complex dimensions of a sustainable freshwater system, and framing scientific knowledge for policy and decision makers. There is an abundance of indicators in use, but considerable variation in terms of what is being measured and how indicators are applied, making it difficult for end-users to identify suitable assessment methods. We review 95 water-related indices and analyze them along their normative, procedural, and systemic dimensions to better understand how problems are being defined, highlight overlaps and differences, and identify the context(s) in which a particular index is useful. We also analyze the intended use, end-users, and geographic scale of application for each index. We find that risk assessment is the most common application (n = 25), with indices in this group typically focusing either on hazard identification (biophysical assessments) or vulnerability of human populations. Indices that measure freshwater ecological health are not explicitly linking these indicators to ecosystem services, and in fact the concept of ecosystem services is rarely (n = 3) used for indicator selection. Resource managers are the most common group of intended end-users (n = 25), but while 28 indices involved consultation with potential end-users, 11 did not specify an intended use. We conclude that indices can be applied as solution-oriented tools, evaluating scenarios and identifying tradeoffs among services and beneficiaries, rather than only assessing and monitoring existing conditions. Finally, earlier engagement of end-users is recommended to help researchers find the right balance among indices' salience, legitimacy, and credibility and thus improve their decision relevance.

Extinction rates in the Anthropocene are three orders of magnitude higher than background and disproportionately occur in the tropics, home of half the world's species. Despite global efforts to combat tropical species extinctions, lack of high-quality, objective information on tropical biodiversity has hampered quantitative evaluation of conservation strategies. In particular, the scarcity of population-level monitoring in tropical forests has stymied assessment of biodiversity outcomes, such as the status and trends of animal populations in protected areas. Here, we evaluate occupancy trends for 511 populations of terrestrial mammals and birds, representing 244 species from 15 tropical forest protected areas on three continents. For the first time to our knowledge, we use annual surveys from tropical forests worldwide that employ a standardized camera trapping protocol, and we compute data analytics that correct for imperfect detection. We found that occupancy declined in 22%, increased in 17%, and exhibited no change in 22% of populations during the last 3-8 years, while 39% of populations were detected too infrequently to assess occupancy changes. Despite extensive variability in occupancy trends, these 15 tropical protected areas have not exhibited systematic declines in biodiversity (i.e., occupancy, richness, or evenness) at the community level. Our results differ from reports of widespread biodiversity declines based on aggregated secondary data and expert opinion and suggest less extreme deterioration in tropical forest protected areas. We simultaneously fill an important conservation data gap and demonstrate the value of large-scale monitoring infrastructure and powerful analytics, which can be scaled to incorporate additional sites, ecosystems, and monitoring methods. In an era of catastrophic biodiversity loss, robust indicators produced from standardized monitoring infrastructure are critical to accurately assess population outcomes and identify conservation strategies that can avert biodiversity collapse.

Terrestrial mammals are a key component of tropical forest communities as indicators of ecosystem health and providers of important ecosystem services. However, there is little quantitative information about how they change with local, regional and global threats. In this paper, the first standardized pantropical forest terrestrial mammal community study, we examine several aspects of terrestrial mammal species and community diversity (species richness, species diversity, evenness, dominance, functional diversity and community structure) at seven sites around the globe using a single standardized camera trapping methodology approach. The sites-located in Uganda, Tanzania, Indonesia, Lao PDR, Suriname, Brazil and Costa Rica-are surrounded by different landscape configurations, from continuous forests to highly fragmented forests. We obtained more than 51 000 images and detected 105 species of mammals with a total sampling effort of 12 687 camera trap days. We find that mammal communities from highly fragmented sites have lower species richness, species diversity, functional diversity and higher dominance when compared with sites in partially fragmented and continuous forest. We emphasize the importance of standardized camera trapping approaches for obtaining baselines for monitoring forest mammal communities so as to adequately understand the effect of global, regional and local threats and appropriately inform conservation actions.

To feed the world without further damaging the planet, Jeffrey Sachs and 24 foodsystem experts call for a global data collection and dissemination network to track the myriad impacts of different farming practices.

Theoretical analyses and experimental studies of synthesized assemblages indicate that under particular circumstances species diversity can enhance community productivity through niche complementarity. It remains unclear whether this process has important effects in mature natural ecosystems where competitive feedbacks and complex environmental influences affect diversity-productivity relationships. In this study, we evaluated diversity-productivity relationships while statistically controlling for environmental influences in 12 natural grassland ecosystems. Because diversity-productivity relationships are conspicuously nonlinear, we developed a nonlinear structural equation modeling (SEM) methodology to separate the effects of diversity on productivity from the effects of productivity on diversity. Meta-analysis was used to summarize the SEM findings across studies. While competitive effects were readily detected, enhancement of production by diversity was not. These results suggest that the influence of small-scale diversity on productivity in mature natural systems is a weak force, both in absolute terms and relative to the effects of other controls on productivity.

The Fifth World Parks Congress in Durban, South Africa, announced in September 2003 that the global network of protected areas now covers 11.5% of the planet's land surface. This surpasses the 10% target proposed a decade earlier, at the Caracas Congress, for 9 out of 14 major terrestrial biomes. Such uniform targets based on percentage of area have become deeply embedded into national and international conservation planning. Although politically expedient, the scientific basis and conservation value of these targets have been questioned. In practice, however, little is known of how to set appropriate targets, or of the extent to which the current global protected area network fulfils its goal of protecting biodiversity. Here, we combine five global data sets on the distribution of species and protected areas to provide the first global gap analysis assessing the effectiveness of protected areas in representing species diversity. We show that the global network is far from complete, and demonstrate the inadequacy of uniform--that is, 'one size fits all'--conservation targets.

The use of umbrella and flagship species as surrogates for regional biota whose spatial distributions are poorly known is a popular conservation strategy. Yet many assumptions underlying the choice of surrogate species remain untested. By using biodiversity databases containing spatial incidence data for species of concern for (i) the southern California coastal sage scrub habitat, (ii) the Columbia Plateau ecoregion, and (iii) the continental United States, we evaluate the potential effectiveness of a range of conservation surrogate schemes (e.g., big carnivores, charismatic species, keystone species, wide-ranging species), asking how many species potentially are protected by each scheme and at what cost in each habitat area. For all three databases, we find that none of the surrogate schemes we evaluated performs significantly better than do a comparable number of species randomly selected from the database. Although some surrogate species may have considerable publicity value, based on the databases we analyzed, representing diverse taxa on three different geographic scales, we find that the utility of umbrella and flagship species as surrogates for regional biodiversity may be limited.