Samenvatting
Selecting among available conservation strategies for endangered animal species requires rigorous evaluation of
intervention effectiveness, cost-efficiency, and long-term viability under projected future conditions. This study evaluates
the outcomes of six conservation strategies -- in situ habitat protection, habitat restoration, ex situ captive breeding with
reintroduction, legal protection enforcement, community-based conservation, and species-specific research programmes
-- applied to sixteen Critically Endangered (CR) or Endangered (EN) vertebrate species across Austria, Germany, and
Italy between 2005 and 2023. Strategy outcomes were quantified using population trend indices derived from long-term
monitoring data (n = 18,284 individual records), population viability analysis (PVA) projections, and cost-effectiveness
ratios (species-years of population stability per 10,000 EUR invested). In situ habitat protection combined with habitat
restoration achieved the highest mean population trend improvement (+2.8% per year; 95% CI: +1.9 to +3.7%) and the
highest cost-effectiveness ratio (4.8 species-years / EUR 10,000) across the sixteen species. Ex situ captive breeding
with reintroduction achieved the highest single-species absolute recovery (European bison Bison bonasus: population
increase +284 individuals over 18 years) but the lowest cost-effectiveness ratio (0.8 species-years / EUR 10,000).
Community-based conservation was the most cost-effective strategy for species in human-dominated landscapes (mean
ratio 3.6 species-years / EUR 10,000). PVA projections under current strategy conditions show that eleven of sixteen
species have > 90% probability of persistence over 100 years, while five remain at high extinction risk requiring strategy
intensification. These findings provide an evidence-based framework for strategy selection and resource allocation in
national species recovery plans under EU Habitats Directive reporting obligations.