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

Björklund H, Valkama J, Tomppo E, Laaksonen T - PLoS ONE (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: The Zoology Unit, Finnish Museum of Natural History Luomus, University of Helsinki, Helsinki, Finland; Department of Biosciences, University of Helsinki, Helsinki, Finland.

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.

No MeSH data available.


Related in: MedlinePlus

Probabilities of successful goshawk breeding based on the best breeding success GLMM (2000 m radius).All breeding attempts with a verified breeding result were included from all breeding periods. Thick line: predicted values, thin lines delineate 95% of the variation between territories in predicted values, dots: data points; 0 = unsuccessful, 1 = successful breeding attempt in the y-axis. (A) Probability of successful breeding along standardized log-ratio proportion of old spruce forest. (B) Probability of successful breeding along standardized log-ratio proportion of young thinning forest. Goshawk breeding success increases with (A) an increasing proportion of old spruce forest and (B) a decreasing proportion of young thinning forest within 2000 m around the nest.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4589344&req=5

pone.0137877.g001: Probabilities of successful goshawk breeding based on the best breeding success GLMM (2000 m radius).All breeding attempts with a verified breeding result were included from all breeding periods. Thick line: predicted values, thin lines delineate 95% of the variation between territories in predicted values, dots: data points; 0 = unsuccessful, 1 = successful breeding attempt in the y-axis. (A) Probability of successful breeding along standardized log-ratio proportion of old spruce forest. (B) Probability of successful breeding along standardized log-ratio proportion of young thinning forest. Goshawk breeding success increases with (A) an increasing proportion of old spruce forest and (B) a decreasing proportion of young thinning forest within 2000 m around the nest.

Mentions: The proportions of old spruce forest (Fig 1A) and water within 2000 m were significantly and positively associated with the breeding success of the goshawk, whereas the proportion of young thinning forest was significantly and negatively associated with goshawk breeding success (Fig 1B, Table 1). To illustrate the results on the biologically interesting original habitat proportion scale, we fitted additional breeding success GLMMs in which the only explanatory variable was each of the untransformed habitat variable proportion in turn at the 2000 m radius scale. Also here, the proportion of old spruce forest showed a significant positive and the proportion of young thinning forest a significant negative association with goshawk breeding success (S4 and S5 Figs). The proportion of built-up land had a significant positive association with goshawk breeding success, whereas the proportion of water and arable land were not significantly associated with goshawk breeding success.


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

Björklund H, Valkama J, Tomppo E, Laaksonen T - PLoS ONE (2015)

Probabilities of successful goshawk breeding based on the best breeding success GLMM (2000 m radius).All breeding attempts with a verified breeding result were included from all breeding periods. Thick line: predicted values, thin lines delineate 95% of the variation between territories in predicted values, dots: data points; 0 = unsuccessful, 1 = successful breeding attempt in the y-axis. (A) Probability of successful breeding along standardized log-ratio proportion of old spruce forest. (B) Probability of successful breeding along standardized log-ratio proportion of young thinning forest. Goshawk breeding success increases with (A) an increasing proportion of old spruce forest and (B) a decreasing proportion of young thinning forest within 2000 m around the nest.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4589344&req=5

pone.0137877.g001: Probabilities of successful goshawk breeding based on the best breeding success GLMM (2000 m radius).All breeding attempts with a verified breeding result were included from all breeding periods. Thick line: predicted values, thin lines delineate 95% of the variation between territories in predicted values, dots: data points; 0 = unsuccessful, 1 = successful breeding attempt in the y-axis. (A) Probability of successful breeding along standardized log-ratio proportion of old spruce forest. (B) Probability of successful breeding along standardized log-ratio proportion of young thinning forest. Goshawk breeding success increases with (A) an increasing proportion of old spruce forest and (B) a decreasing proportion of young thinning forest within 2000 m around the nest.
Mentions: The proportions of old spruce forest (Fig 1A) and water within 2000 m were significantly and positively associated with the breeding success of the goshawk, whereas the proportion of young thinning forest was significantly and negatively associated with goshawk breeding success (Fig 1B, Table 1). To illustrate the results on the biologically interesting original habitat proportion scale, we fitted additional breeding success GLMMs in which the only explanatory variable was each of the untransformed habitat variable proportion in turn at the 2000 m radius scale. Also here, the proportion of old spruce forest showed a significant positive and the proportion of young thinning forest a significant negative association with goshawk breeding success (S4 and S5 Figs). The proportion of built-up land had a significant positive association with goshawk breeding success, whereas the proportion of water and arable land were not significantly associated with goshawk breeding success.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: The Zoology Unit, Finnish Museum of Natural History Luomus, University of Helsinki, Helsinki, Finland; Department of Biosciences, University of Helsinki, Helsinki, Finland.

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.

No MeSH data available.


Related in: MedlinePlus