Nestbox provision is a technique used to increase nest‐site availability for secondary cavity‐nesting birds. However, little is known about the demographic consequences of nestbox provision in different habitat types. To assess how nestbox provision affects the density of hole‐nesting birds simultaneously in two contrasting habitats, we compared the breeding density of Great Tits along transects without nestboxes with that in transects where nestboxes were provided. Although the initial density of breeders was considerably higher in the deciduous habitat than in the coniferous habitat, provision of nestboxes increased density by a similar number of additional pairs in each habitat type. Thus, the provision of nestboxes in managed coniferous forests may be as effective in increasing the breeding opportunities of cavity nesters as in deciduous stands. Moreover, previous research showed that pairs in deciduous habitat with nestboxes have consistently lower breeding success than those in coniferous habitat with nestboxes. It is possible that the addition of nestboxes in the preferred habitat increased density to such an extent that density‐dependent effects became apparent.
We assessed ecological sustainability of seminatural forestry by analyzing 80-year dynamics and the current distribution of all woodpecker species in Estonia. We found that, despite the clear-cutting-based forestry system, woodpeckers inhabited commercial seminatural forests in substantial numbers, including the species generally considered vulnerable to timber harvesting. The only negative trend, a drastic decline in the Green Woodpecker, paralleled the loss of seminatural, wooded grasslands and is mostly an issue for landscape planning and agricultural land use. Major silvicultural factors supporting other species in commercial forests include natural regeneration with multiple native tree species and deadwood abundance. In such context, the main role of protected areas is to provide ecological resilience; however, we estimated that the current strict reserves could further double their carrying capacities for woodpeckers through successional recovery and, perhaps, active restoration. The long time series used were instrumental in detecting unexpected dynamics and the impacts of climatically extreme years. We conclude that (1) seminatural forestry can serve as a basis for reconciling timber harvesting and biodiversity protection at the landscape scale, given appropriate attention to key structures and landscape zoning and (2) woodpeckers represent a biological indicator system for the sustainability of forest landscapes in Europe.
Context The Eurasian crane (Grus grus) is an iconic and sensitive species. It is therefore necessary to understand its landscape ecology in order to determine threats. Objectives (1) To map the distribution of cranes and then model their habitat requirements in Estonia, linked to the current level of protection. (2) To determine the environmental characteristics of, and the habitats present in, sites utilized by the birds, and their sensitivity to change.Methods (1) The distribution of cranes was recorded by observation and by tracking individuals. A model of potential breeding sites was compared with the occurrence of the bird in Estonia and then linked to protected sites. (2) The seasonal distribution of the bird was overlaid with a European environmental classification and the CORINE land cover map. A model of climate change was also utilized.
Results (1) A new map of European migration routes, wintering and stopover sites is presented. (2)The bird requires a habitat network, with wetlands being essential for nesting and roosting. The composition of habitats used for feeding varies according to geographical location. (3) In Estonia not all potential breeding sites are occupied and many existing sites are not protected. (4) Climate change could threaten populations in the south but could be beneficial in Estonia.Conclusions (1) The existing ecological network in Estonia is adequate to maintain a viable breeding population of the Eurasian crane. (2) Climate change could support the breeding of cranes but complicate their migration and wintering.
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