A sampling strategy for assessing habitat coverage at a broad spatial scale

The quantitative assessment of habitat conservation status is a major task for European Union member states in compliance with Council Directive 92/43. One goal the 2030 Biodiversity Strategy effective management habitats that show declining trends. While various approaches have been adopted national assessments, there no consensus on how to achieve common statistically sound estimates criteria indicated by EU evaluation and trend types. Here, we present an adaptive monitoring approach based two-phase sampling scheme estimate coverage terrestrial types, which one four Habitats Directive. We used 9 distributed among different choosing Italy as case study. development methodological described, simulation study was performed check precision estimators accounting lack sampled data (nonresponse treatment), subregions sustainable effort. found our has potential increase estimating types (approximated at 1 ha cell size) respect achieved simple random without replacement, simplest approach. Adopting small fraction (⩽0.04%) survey area, relative standard errors ranged from 7 15% whose presence strongly correlated suitability scores furnished expert team. In challenging context “mandated” type, provides statistical possibility applying standardised transferable easily repeatable over time.