What is a unit of nature? Measurement challenges in the emerging biodiversity credit market.

Bending the curve of biodiversity loss requires the business and financial sectors to disclose and reduce their biodiversity impacts and help fund nature recovery. This has sparked interest in developing generalizable, standardized measurements of biodiversity-essentially a 'unit of nature'. We examine how such units are defined in the rapidly growing voluntary biodiversity credits market and present a framework exploring how biodiversity is quantified, how delivery of positive outcomes is detected and attributed to the investment and how the number of credits issued is adjusted to account for uncertainties.

Protected areas have a mixed impact on waterbirds, but management helps.

International policy is focused on increasing the proportion of the Earth's surface that is protected for nature. Although studies show that protected areas prevent habitat loss, there is a lack of evidence for their effect on species' populations: existing studies are at local scale or use simple designs that lack appropriate controls. Here we explore how 1,506 protected areas have affected the trajectories of 27,055 waterbird populations across the globe using a robust before-after control-intervention study design, which compares protected and unprotected populations in the years before and after protection.

Evaluating Impact Using Time-Series Data.

Humanity's impact on the environment is increasing, as are strategies to conserve biodiversity, but a lack of understanding about how interventions affect ecological and conservation outcomes hampers decision-making. Time series are often used to assess impacts, but ecologists tend to compare average values from before to after an impact; overlooking the potential for the intervention to elicit a change in trend. Without methods that allow for a range of responses, erroneous conclusions can be drawn, especially for large, multi-time-series datasets, which are increasingly available.

Estimating the risk of species interaction loss in mutualistic communities.

Interactions between species generate the functions on which ecosystems and humans depend. However, we lack an understanding of the risk that interaction loss poses to ecological communities. Here, we quantify the risk of interaction loss for 4,330 species interactions from 41 empirical pollination and seed dispersal networks across 6 continents.

The major barriers to evidence-informed conservation policy and possible solutions.

Conservation policy decisions can suffer from a lack of evidence, hindering effective decision-making. In nature conservation, studies investigating why policy is often not evidence-informed have tended to focus on Western democracies, with relatively small samples. To understand global variation and challenges better, we established a global survey aimed at identifying top barriers and solutions to the use of conservation science in policy.

Worldwide insect declines: An important message, but interpret with caution.

A recent paper claiming evidence of global insect declines achieved huge media attention, including claims of "insectaggedon" and a "collapse of nature." Here, we argue that while many insects are declining in many places around the world, the study has important limitations that should be highlighted. We emphasise the robust evidence of large and rapid insect declines present in the literature, while also highlighting the limitations of the original study.

A snapshot of biodiversity protection in Antarctica.

Threats to Antarctic biodiversity are escalating, despite its remoteness and protection under the Antarctic Treaty. Increasing human activity, pollution, biological invasions and the omnipresent impacts of climate change all contribute, and often combine, to exert pressure on Antarctic ecosystems and environments. Here we present a continent-wide assessment of terrestrial biodiversity protection in Antarctica.

Restoring islands and identifying source populations for introductions.

Article impact statement: Structured decision making can be used to identify an optimal source population for conservation introductions.

Rapid climate-driven loss of breeding habitat for Arctic migratory birds.

Millions of birds migrate to and from the Arctic each year, but rapid climate change in the High North could strongly affect where species are able to breed, disrupting migratory connections globally. We modelled the climatically suitable breeding conditions of 24 Arctic specialist shorebirds and projected them to 2070 and to the mid-Holocene climatic optimum, the world's last major warming event ~6000 years ago. We show that climatically suitable breeding conditions could shift, contract and decline over the next 70 years, with 66-83% of species losing the majority of currently suitable area.