Biology subjects

Akcakaya, H. R.

Publications and source records attributed to Akcakaya, H. R..

4 recordsLinked to original sources

bioRxiv2026

Identifying and ranking species that need urgent management action to achieve Target 4 of the Global Biodiversity Framework

Target 4 of the Kunming-Montreal Global Biodiversity Framework (KMGBF) calls for urgent management actions to halt humaninduced extinctions and enable species recovery. However, most Parties face substantial challenges in determining which species require urgent management actions. Here, we present a transparent, standardised protocol that identifies and ranks species most likely to need urgent management actions at the national level, using globally available data from the IUCN Red List of Threatened Species. The protocol integrates four criteria aligned with Target 4: global extinction risk, rate of decline, population or range restriction, and endemism, to generate a national ranked list of species. Species scoring highly on these four criteria, and therefore most in need of urgent management action, are ranked most highly. We applied this method to all 250 countries and territories listed in the IUCN Red List and pilottested national rankings with participants from eight diverse countries. Across pilots, participants reported that the ranked lists were scientifically robust, timesaving, and valuable starting points for national prioritysetting, while stating the importance of national context, and the need for additional technical and financial support for implementation. Our results demonstrate that a sciencebased approach can meaningfully support Parties in identifying species requiring urgent action under Target 4, in a standardised way. With 2030 approaching rapidly, this protocol provides an immediate, practical tool to accelerate progress toward halting extinctions and advancing species recovery.

ecology↗

bioRxiv2023

Modelling the probability of meeting IUCN Red List criteria to support reassessments.

Comparative extinction risk analysis - which predicts species extinction risk from correlation with traits or geographical characteristics - has gained research attention as a promising tool to support extinction risk assessment in the IUCN Red List of Threatened Species. However, its uptake has been very limited so far, possibly because these models only predict a species Red List category, without indicating which Red List criteria may be triggered by which such approaches cannot easily be used in Red List assessments. We overcome this implementation gap by developing models that predict the probability of species meeting individual Red List criteria. Using data on the worlds birds, we evaluated the predictive performance of our criterion-specific models and compared it with the typical criterion-blind modelling approach. We compiled data on biological traits (e.g., range size, clutch size) and external drivers (e.g., change in canopy cover) often associated with extinction risk. For each specific criterion, we modelled the relationship between extinction risk predictors and species Red List category under that criterion using ordinal regression models. We found criterion-specific models were better at predicting threatened species compared to a criterion-blind model (higher sensitivity), but less good at predicting not threatened species (lower specificity). As expected, different covariates were important for predicting threat status under different criteria, for example change in annual temperature was important to predict criteria related to population trends, while clutch size was important for criteria related to restricted area of occupancy or small population size. Our criteria-specific method can support Red List assessors by producing outputs that identify species likely to meet specific criteria, and which are the most important predictors: these species can be prioritised for re-evaluation. We expect this new approach to increase the uptake of extinction risk models in Red List assessments, bridging a long-standing research-implementation gap.

ecology↗

bioRxiv2021

Humans hastened the range collapse and extinction of woolly mammoth

Pathways to extinction start long before the death of the last individual. However, causes of early-stage population declines and the susceptibility of small residual populations to extirpation are typically studied in isolation. Using validated process-explicit models, we disentangle the ecological mechanisms and threats that were integral in the initial decline and later extinction of the woolly mammoth. We show that reconciling ancient DNA data on woolly mammoth population decline with fossil evidence of location and timing of extinction requires process-explicit models with specific demographic and niche constraints, and a constrained synergy of climatic change and human impacts. Validated models needed humans to hasten climate-driven population declines by many millennia, and to allow woolly mammoths to persist in mainland Arctic refugia until the mid-Holocene. Our results show that the role of humans in the extinction dynamics of woolly mammoth began well before the Holocene, exerting lasting effects on the spatial pattern and timing of its range-wide extinction.

ecology↗

bioRxiv2020

Preventing extinctions post-2020 requires recovery actions and transformative change

Stopping human-induced extinctions will require strong policy commitments that comprehensively address threats to species. In 2021, a new Global Biodiversity Framework will be agreed by the Convention on Biological Diversity. Here we investigate how the suggested targets could contribute to reducing threats to threatened vertebrates, invertebrates, and plants, and assess the importance of a proposed target to implement recovery actions for threatened species. We find that whilst many of the targets benefit species, extinction risk for over one third of threatened species would not be reduced sufficiently without a target on recovery actions, including ex situ conservation, reintroductions and other species-specific interventions. A median of 41 threatened species per country require such actions, and they are found in most countries of the world. To prevent future extinctions, policy commitments must include recovery actions for the most threatened species in addition to broader transformative change.

ecology↗