Search

For the concept of nature positive to succeed as the lodestar for international action on biodiversity conservation, it must build upon lessons learned from the application of the mitigation hierarchy — or risk becoming mere greenwash.

Biodiversity offsetting is a globally influential policy mechanism for reconciling trade-offs between development and biodiversity loss. However, there is little robust evidence of its effectiveness. We evaluated the outcomes of a jurisdictional offsetting policy (Victoria, Australia). Offsets under Victoria's Native Vegetation Framework (2002–2013) aimed to prevent loss and degradation of remnant vegetation, and generate gains in vegetation extent and quality. We categorised offsets into those with near-complete baseline woody vegetation cover (“avoided loss”, 2702 ha) and with incomplete cover (“regeneration”, 501 ha), and evaluated impacts on woody vegetation extent from 2008 to 2018. We used two approaches to estimate the counterfactual. First, we used statistical matching on biophysical covariates: a common approach in conservation impact evaluation, but which risks ignoring potentially important psychosocial confounders. Second, we compared changes in offsets with changes in sites that were not offsets for the study duration but were later enrolled as offsets, to partially account for self-selection bias (where landholders enrolling land may have shared characteristics affecting how they manage land). Matching on biophysical covariates, we estimated that regeneration offsets increased woody vegetation extent by 1.9%–3.6%/year more than non-offset sites (138–180 ha from 2008 to 2018) but this effect weakened with the second approach (0.3%–1.9%/year more than non-offset sites; 19–97 ha from 2008 to 2018) and disappeared when a single outlier land parcel was removed. Neither approach detected any impact of avoided loss offsets. We cannot conclusively demonstrate whether the policy goal of ‘net gain’ (NG) was achieved because of data limitations. However, given our evidence that the majority of increases in woody vegetation extent were not additional (would have happened without the scheme), a NG outcome seems unlikely. The results highlight the importance of cons, Biodiversity offsetting is a globally influential policy mechanism for reconciling trade-offs between development and biodiversity loss. However, there is little robust evidence of its effectiveness. We evaluated the outcomes of a jurisdictional offsetting policy (Victoria, Australia). Offsets under Victoria's Native Vegetation Framework (2002–2013) aimed to prevent loss and degradation of remnant vegetation, and generate gains in vegetation extent and quality. We categorised offsets into those with near-complete baseline woody vegetation cover (“avoided loss”, 2702 ha) and with incomplete cover (“regeneration”, 501 ha), and evaluated impacts on woody vegetation extent from 2008 to 2018. We used two approaches to estimate the counterfactual. First, we used statistical matching on biophysical covariates: a common approach in conservation impact evaluation, but which risks ignoring potentially important psychosocial confounders. Second, we compared changes in offsets with changes in sites that were not offsets for the study duration but were later enrolled as offsets, to partially account for self-selection bias (where landholders enrolling land may have shared characteristics affecting how they manage land). Matching on biophysical covariates, we estimated that regeneration offsets increased woody vegetation extent by 1.9%–3.6%/year more than non-offset sites (138–180 ha from 2008 to 2018) but this effect weakened with the second approach (0.3%–1.9%/year more than non-offset sites; 19–97 ha from 2008 to 2018) and disappeared when a single outlier land parcel was removed. Neither approach detected any impact of avoided loss offsets. We cannot conclusively demonstrate whether the policy goal of ‘net gain’ (NG) was achieved because of data limitations. However, given our evidence that the majority of increases in woody vegetation extent were not additional (would have happened without the scheme), a NG outcome seems unlikely. The results highlight the importance of c

Bioacoustics offers new ways to monitor wildlife populations. Understanding vocal changes related to age can provide demographic data that are valuable but difficult to collect for threatened species. Here, we present the vocal signals of ontogeny and fledging in nestlings for two endangered black-cockatoos, the Kangaroo Island glossy black-cockatoo, Calyptorhynchus lathami halmaturinus, and the south-eastern red-tailed black-cockatoo, C. banksii graptogyne. Using sound recordings taken at wild nests (n = 3 for the red-tailed black-cockatoo; n = 7 for the glossy black-cockatoo), we examined changes in nestling vocalisations through to fledging. Nestlings vocalised from 4 weeks of age, but calls were soft and infrequent until about 6 weeks. Daily call rate increased significantly in the final week of nesting. Peak amplitude increased significantly with development for both subspecies. Call duration increased significantly for the glossy black-cockatoo. Likewise, low frequency increased significantly for the glossy black-cockatoo. Average entropy decreased significantly for both subspecies. Aggregate entropy decreased significantly for the red-tailed black-cockatoo. Fledging was associated with a loud and distinct vocal event. Together, these changes in call rate and structure, and the presence or absence of fledging vocalisations, provide useful ways to broadly categorise nest age and determine nest outcome from sound recordings.

Ecologists are increasingly using bioacoustics in wildlife monitoring programs. Remote autonomous sound recorders provide new options for collecting data for species and in contexts that were previously difficult. However, post-processing of sound files to extract relevant data remains a significant challenge. Detection algorithms, or call recognizers, can aid automation of species detection but their performance and reliability has been mixed. Further, building recognizers typically requires either costly commercial software or expert programming skills, both of which reduces their accessibility to ecologists responsible for monitoring. In this study we investigated the performance of open-source call recognizers provided by the monitoR package in R, a language popular among ecologists. We tested recognizers on sound data collected under natural conditions at nests of two endangered subspecies of black-cockatoo, the Kangaroo Island glossy black-cockatoo Calyptorhynchus lathami halmaturinus (n = 23 nests), and the south-eastern red-tailed black-cockatoo Calyptorhynchus banksii graptogyne (n = 20 nests). Specifically, we tested the performance of binary point matching recognizers in confirming daily nest activity (active or inactive) and nesting outcome (fledge or fail). We tested recognizers on recordings from nests of known status using 3 × 3-h recordings per nest, from early, mid and late stages of the recording period. Daily nest activity was correctly assigned in 61.7% of survey days analysed (n = 60 days) for the red-tailed black-cockatoo, and 62.3% of survey days (n = 69 days) for the glossy black-cockatoo. Fledging was successfully detected in all cases. Precision (true positive / true positive + false positive) of individual detections was 70.2% for the south-eastern red-tailed black-cockatoo and 37.1% for the Kangaroo Island glossy black-cockatoo. Manual verification of outputs is still required, but it is not necessary to verify all detections to confir

Increasingly, government and corporate policies on ecological compensation (e.g., offsetting) are requiring “net gain” outcomes for biodiversity. This presents an opportunity to align development with the United Nations Conven-tion on Biological Diversity Post-2020 Global Biodiversity Framework's (GBF) proposed ambition for overall biodiversity recovery. In this perspective, we describe three conditions that should be accounted for in net gain policy to align outcomes with biodiversity recovery goals: namely, a requirement for residual losses from development to be compensated for by (1) absolute gains,which are (2) scaled to the achievement of explicit biodiversity targets, where(3) gains are demonstrably feasible. We show that few current policies meet these conditions, which risks undermining efforts to achieve the proposed Post-2020 GBF milestones and goals, as well as other jurisdictional policy imperatives to halt and reverse biodiversity decline. To guide future decision-making, we provide a supporting decision tree outlining net gain compensation feasibility.