Browsing by Subject "major in Ecology and Evolutionary Biology"

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  • Santangeli, Andrea (Helsingin yliopisto, 2013)
    Humans are the main cause of the on-going large-scale biodiversity crisis, mostly through processes like habitat loss and fragmentation, and habitat degradation. The recent recognition of the scale and rate of biodiversity erosion has stimulated strong political and institutional reactions, culminating in the implementation of a large number of conservation initiatives. Such efforts have been largely insufficient to revert or slow down the rapid loss of biodiversity. Commonly, conservation resources have been allocated based on decisions supported by traditional knowledge or expert opinion rather than scientific evidence. Therefore, it is relevant that interventions are evaluated, to ultimately allow learning from past actions and taking better decisions in the future. With this thesis I aim to provide evidence needed to improve the effectiveness of different approaches to conservation of some species affected by anthropogenic activities. In doing so, I considered conservation interventions implemented mostly on private land with different underlying approaches: voluntary and inexpensive (based on self-motivation of landowners); voluntary market-based (landowners are compensated); Compulsory land reservation or legislation (landowners have no choice). I first evaluate the effectiveness of a conservation program aimed at protecting raptor nests in private forests of North Karelia in eastern Finland. I show that here an inexpensive voluntary approach, based on self-motivation of landowners, may represent an effective instrument for achieving conservation with very limited financial resources. This approach was effective not only at eliciting participation of local forest owners, but it also provided ecological benefits to the raptor species considered. Relevant outcomes for practical conservation can also emerge when multiple interventions are compared. This was the case for nest protection of the Montagu s harrier breeding in cropland of Spain and France. In France, protection of nests from harvesting operations has been achieved on a voluntary basis. Here I show that the most effective interventions to enhance nest productivity were those that not only protect from harvesting, but also from predation. This was achieved by erecting a protective fence around the nest. On the other hand, some nest protection measures in Spain were more expensive due to payments to farmers. Here, temporary removal of the chicks during harvest operations or relocation of the nest to a nearby safe place, as well as harvest delay, were the most effective measures to enhance nest productivity. Harvest delay was also the most expensive among all measures, therefore removal or relocation of the nest should be prioritized wherever it is operationally feasible. Interestingly, the most commonly employed measure, the retention of a small buffer of un-harvested crop, was also less effective compared to the other means. Unexpected but positive outcomes for conservation management emerged also from an evaluation of the effects of nest site protection for breeding White-tailed eagles in south-western Finland. The species was breeding as often and successfully in protected and unprotected areas, which suggests that compulsory and expensive protection through land reservation may not be necessary under the studied conditions. The species apparently thrives also in unprotected land subject to some levels of anthropogenic activities. I found opposite results in a study on protection of flying squirrel sites in Finland. Here I provide evidence indicating that the enforced legislation to protect the species habitat in Finnish forests is ineffective. The species occupancy at sites protected according to the law strongly declined following tree harvest. This indicates that the primary objective of the legislation (i.e. prevent deterioration of the sites where the species occurs) are not met. This is due to the fact that conservation of flying squirrel s habitat may conflict with forestry interests, and thus restrictions have been largely set in favour of the latter and at the detriment of the former. The case studies presented here indicate that evaluating the effectiveness of past actions is important. This step allows understanding whether past efforts have reached their initial objectives. Only with the strength of this evidence it is possible to adaptively revise current conservation plans and increase the chances of reaching the desired outcome from any given action. This is particularly relevant in the modern era, where conservation challenges are enormous, and the resources limited. Therefore, it is crucial that any implemented effort produces the best possible outcome for conservation.