Home-range ecology of seven Palaearctic steppe bird species: a meta-analysis of spatial dimensions and ecological knowledge gaps

Abstract

Home range size (HRS) is a key metric in spatial ecology and conservation, but published estimates often differ across studies due to variation in ecological context, demographic composition (sex, age), annual cycle period, and tracking technology. Steppe birds –among the most threatened avian groups in Europe and globally– is a conservation-relevant group for which synthesising dispersed information on spatial requirements such as HRS may help support environmental impact assessment, habitat management and spatial planning across their distribution. We performed a systematic literature review and multi-species meta-analysis of HRS for seven Palearctic non-passerine steppe bird species of conservation concern. We retained 39 primary studies. Geographic and ecological coverage was strongly biased. Most research was conducted in western Europe, while large parts of the species’ breeding ranges –including eastern Europe, western and central Asia, northern Africa- and wintering areas were poorly represented. Studies were mainly carried out in arable land, with little information from other key habitats for the species like natural grasslands and shrublands. Despite the widespread availability of GPS technology, VHF tracking dominated published estimates. When comparable, GPS-based estimates tended to report larger and more variable home ranges. Available information was dominated by adult males during the breeding season, which represented 75.6% of all monitored individuals ( N = 623), whereas information on females, subadults, juveniles and non-breeding periods was less represented. The main knowledge gaps identified in the literature available were related to limited geographic and habitat coverage, underreporting of GPS-based home range estimates, and lack of data across demographic groups and annual cycle stages. HRS is a context-dependent property shaped by individual behaviour, seasonal variation and local environmental conditions, and extrapolating estimates across sexes, ages, seasons or habitat contexts can misinform management. We further recommend that studies using GPS technology report basic HRS metrics, even when home range estimation is not the primary focus of the research. Broadening GPS-based research to include underrepresented demographic groups, regions and habitat contexts would enhance ecological knowledge and improve the robustness of environmental assessments and conservation planning.