Habitat Effects on the Breeding Performance of Three Forest-Dwelling Hawks

Abstract

Habitat loss causes population declines, but the mechanisms are rarely known. In the European Boreal Zone, loss of old forest due to intensive forestry is suspected to cause declines in forest-dwelling raptors by reducing their breeding performance. We studied the boreal breeding habitat and habitat-associated breeding performance of the northern goshawk (Accipiter gentilis), common buzzard (Buteo buteo) and European honey buzzard (Pernis apivorus). We combined long-term Finnish bird-of-prey data with multi-source national forest inventory data at various distances (100–4000 m) around the hawk nests. We found that breeding success of the goshawk was best explained by the habitat within a 2000-m radius around the nests; breeding was more successful with increasing proportions of old spruce forest and water, and decreasing proportions of young thinning forest. None of the habitat variables affected significantly the breeding success of the common buzzard or the honey buzzard, or the brood size of any of the species. The amount of old spruce forest decreased both around goshawk and common buzzard nests and throughout southern Finland in 1992–2010. In contrast, the area of young forest increased in southern Finland but not around hawk nests. We emphasize the importance of studying habitats at several spatial and temporal scales to determine the relevant species-specific scale and to detect environmental changes. Further effort is needed to reconcile the socioeconomic and ecological functions of forests and habitat requirements of old forest specialists.

Interactive influences of fluctuations of main food resources and climate change on long-term population decline of Tengmalm’s owls in the boreal forest

“…This interpretation was also supported by the fact that start of egg-laying was delayed during 1970s-2010s although ambient temperatures increased and snow depth simultaneously did not increase prior to and during the egg-laying period. It is alarming that in similar adverse situation due to forest habitat loss and degradation in boreal zone are many forest-specialists belonging to different taxa [113][114][115][116][117][118][119][120][121] , and the situation may deteriorate as climate change progresses [2][3][4]122 , unless major measures to reverse this situation are taken and actually implemented as soon as possible.…”

Assessing the provisioning potential of ecosystem services in a Scandinavian boreal forest: Suitability and tradeoff analyses on grid-based wall-to-wall forest inventory data

“…Recent developments of remote sensing (RS) technologies have brought spatially explicit estimates of various forest inventory, structure and habitat related parameters available for vast areas (Tomppo et al, 2008a(Tomppo et al, ,b, 2014Maltamo et al, 2014;Barrett et al, 2016). For instance, generalizing field plot measurements using coarse-or medium-resolution RS and other numeric map data, referred to as Multi-Source National Forest Inventory (MS-NFI; Tomppo et al, 2008a) has been used to generate pixel-wise (Tuominen et al, 2010) or aggregated (Mäkelä et al, 2011) maps of biomass-related attributes, carbon storage (Akujärvi et al, 2016;Mononen et al, 2017), biological diversity (Lehtomäki et al, 2009(Lehtomäki et al, , 2015Räsänen et al, 2015), habitats (Vatka et al, 2014;Björklund et al, 2015) or berry yields (Kilpeläinen et al, 2016). Applying RS data to analyze multiple forest ESs, Frank et al (2015) evaluated the biomass provisioning potential and tradeoffs for other ESs, when the land use of a region located in Germany was expected to change according to climate-adapted management scenarios.…”

Female turnover rate differs between two Northern GoshawkAccipiter gentilisnesting areas, as revealed byDNAanalysis of moulted feathers

“…is close to that reported from urban areas (Rutz et al 2006), where human persecution is less likely because of reduced conflict with hunters. In some Finnish studies, the proportion of successful nesting attempts was also high, around 87%, as recorded both from artificial nests and in questionnaire data (Bj€ orklund et al 2013(Bj€ orklund et al , 2015. However, many estimates of successful nesting attempts are probably too high, because successful nesting in newly found nests in a breeding season is usually included, whereas unsuccessful newly built nests, which are difficult to find, will often be underrecorded.…”