Expert knowledge assessment of threats and conservation strategies for breeding Hen Harrier and Short-eared Owl across Europe

Abstract

Summary Hen Harrier Circus cyaneus and Short-eared Owl Asio flammeus are open-country birds of prey with overlapping distributions. Although both species face similar conservation threats across their ranges, work to date has largely been undertaken at a national scale with few attempts to collate and assess factors relevant to their conservation at an international scale. Here we use an expert knowledge approach to evaluate the impact of conservation threats and the effectiveness of conservation strategies for each species across Europe. We report results of responses to a questionnaire from 23 Hen Harrier experts from nine countries and 12 Short-eared Owl experts from six countries. The majority of responses for both species reported declines in breeding numbers. The perceived impact of threats was broadly similar for both species: ecological factors (predation, extreme weather and prey availability), changes in land use (habitat loss and agricultural intensification) and indirect persecution (accidental nest destruction) were considered to be the greatest threats to breeding Hen Harrier and Short-eared Owl. Short-eared Owl experts also highlighted lack of knowledge and difficulties associated with monitoring as a major conservation challenge. Despite broad-scale similarities, geographical variation was also apparent in the perceived importance of conservation threats, with some threats (such as direct persecution, large-scale afforestation or habitat degradation) requiring country-specific actions. Implementation of different conservation strategies also varied between countries, with the designation of protected areas reported as the most widespread conservation strategy adopted, followed by species and habitat management. However, protected areas (including species-specific protected areas) were perceived to be less effective than active management of species and habitats. These findings highlight the overlap between the conservation requirements of these two species, and the need for collaborative international research and conservation approaches that prioritise pro-active conservation strategies subject to continued assessment and with specific conservation goals.

Caution Is Needed When Using Niche Models to Infer Changes in Species Abundance: The Case of Two Sympatric Raptor Populations

“…The concept of carrying capacity encapsulates the notion that habitat resources must ultimately limit the numbers of raptors in an area. Nevertheless, factors other than those purely related to habitat characteristics (e.g., human pressure, intra-and interspecific interactions, period of the annual cycle) are known to affect local abundance and population dynamics [44,45]. Although our findings showed that species abundance and habitat suitability are significantly correlated, they also indicated that changes in abundance between 1997 and 2017 are not exclusively determined by changes in habitat suitability.…”

Weather conditions determine reproductive success of a ground-nesting bird of prey in natural dune grasslands

“…Within Central Europe, both natural (e.g., bogs, coastal dunes, and marshes) and manmade habitats (e.g., agricultural land) are used for breeding (Keller et al 2020). Habitat loss and degradation, increased predation and reduced prey availability are considered to be the main threats of the Short-eared Owl in this part of its range (Fernández-Bellon et al 2020).…”

“…As a result, it is considered a species of conservation concern in Europe (Calladine et al 2012;Fernandez-Bellon et al 2020) and threatened with extinction in Germany (Ryslavy et al 2020). The owl has especially suffered from habitat loss and degradation due to agricultural intensification, increased predation and reduced prey availability (Fernández-Bellon et al 2020).…”

Interactive effects of agricultural landscape heterogeneity and weather conditions on breeding density and reproductive success of a diurnal raptor

“…In avian populations, negative responses to the changing climate have been documented globally (e.g. Both et al, 2006;Stephens et al, 2016), and in birds of prey, climate change has been proposed to influence many long-term population declines that have occurred in the past decades (Catry et al, 2011;Fernández-Bellon et al, 2020;Schmidt et al, 2012;Steenhof & Peterson, 2009). As birds of prey generally possess long life history cycles while their prey species with short generation times are capable of rapid responses to environmental shifts, they are particularly susceptible to drastic ecological changes (Meserve et al, 2003;Newton, 1979;Sergio et al, 2008).…”