R. Jochem

Sacrificing patches for linear habitat elements enhances metapopulation performance of woodland birds in fragmented landscapes

It is generally assumed that large patches of natural habitat are better for the survival of species than the same amount of habitat in smaller fragments or linear elements like hedges and tree rows. We use a spatially explicit individual-based model of a woodland bird to explore this hypothesis. We specifically ask whether mixtures of large, small and linear habitat elements are better for population performance than landscapes that consist of only large elements. With equal carrying capacity, metapopulations perform equally or better in heterogeneous landscape types that are a mix of linear, large and small habitat elements. We call this increased metapopulation performance of large and small elements “synergy”. These mixed conditions are superior because the small linear elements facilitate dispersal while patches secure the population in the long run because they have a lower extinction risk. The linear elements are able to catch and guide dispersing animals which results in higher connectivity between patches leading to higher metapopulation survival. Our results suggest that landscape designers should not always seek to conserve and create larger units but might better strive for more variable landscapes with mixtures of patch sizes and shapes. This is especially important when smaller units play a key role in connecting patches and dispersal through the matrix is poor.

Landscape prerequisites for the survival of a modelled metapopulation and its neutral genetic diversity are affected by climate change

In response to climate change a species may move, adapt, or go extinct. For the adaptability of a population its genetic diversity is essential, but climate change-induced range shifts can cause a loss of genetic diversity. We investigated how landscape structure affects the level and distribution of genetic diversity in metapopulations subject to climate change-induced range shifts. For this we used the spatially explicit, individual-based model METAPHOR which simulates metapopulation demography and genetics under different temperature increase scenarios. The results indicated that increasing total habitat area may enhance the maintenance of the genetic diversity in metapopulations while they are shifting their range under climate change. However, the results also showed that a high level of total habitat area did not prevent the populations in the newly colonised habitat area of being depleted of much of the original genetic diversity. We therefore conclude that enhancing landscape connectivity may lead to a delayed loss of genetic diversity in metapopulations under climate change, but that additional measures would be necessary to ensure its long-term conservation. Importantly, our simulations also show that a landscape which could be regarded as well-structured under stable climatic conditions, may be inferior for the conservation of genetic diversity during a range shift. This is important information for landscape management when developing strategies for the in situ conservation of genetic variation in natural populations under climate change.

Reconsidering the Effectiveness of Scientific Tools for Negotiating Local Solutions to Conflicts between Recreation and Conservation with Stakeholders

The conflict between the conservation of biodiversity and recreation activities in the European landscape is intensifying. Managers of large nature areas are confronted with increasing numbers of visitors and decreasing biodiversity values. To accommodate the visitors while simultaneously protecting the biodiversity values they need to make changes in the landscape. Current legislation, a lack of knowledge on the recreation-biodiversity relationship, and the diverging point of view of stakeholders make it difficult to find consensual solutions. New approaches such as adaptive management and boundary management can help managers and stakeholders in the process of decision making. In these approaches the role of scientists has changed, as has the use of their tools. Using two research projects in Europe we explore how scientific tools are used in this new context. We argue that such tools (1) should be built on the interactions between recreation and biodiversity functions, (2) can be used interactively to encourage stakeholders to engage in a learning process, (3) allow local knowledge and data to be incorporated into them, and (4) generate output in the form of a map showing where the conflict areas and opportunities are located. These four key features will help managers to improve communication between themselves, stakeholders, and scientists, increase consensus between stakeholders on how the conflict should be perceived, explore solutions, and generate new knowledge. For future research we suggest investigating how adaptive management and boundary management can be used in a stepwise learning strategy and how uncertainties in the tools affect the learning process.

RETRACTED ARTICLE : The effectiveness of green infrastructure as a climate adaptation strategy for intensively-used landscapes: an example of the great crested newt

This article has been retracted at the request of the authors. After publication the authors detected an error in the dispersal module that estimates colonisation probabilities for dispersing individuals, partially inflating long distance dispersal probabilities. As the dispersal model is at the core of the work presented, this error may have consequences for the results presented and conclusions drawn. While assessing the exact magnitude of the impact of the error is undergoing, the authors believe that the results presented here are too preliminary, for which they requested to retract this publication.

MetaNatuurplanner v4.0 - Status A : Toepassing voor Evaluatie Natuurpact

Wageningen Environmental Research and PBL Netherlands Environmental Assessment Agency have developed MNP version 4.0 (Model for Nature Policy; MetaNatuurplanner) to determine the impacts of policy and management activities on biodiversity at the national and regional scale. The model predicts the persistence of species protected under nature policy by assessing the availability of sufficiently large connected areas of good habitat quality in the landscape . It does not assess the actual presence of these species. The model uses correlations between environmental, water and land use parameters and the sustainable conservation of biodiversity, and is used for identifying conflicts, policy evaluation and national and regional scenario studies. Results are aggregated to form indicators for Dutch and European policy. This report describes all the aspects of the model that are needed to obtain the Statutory Research Tasks Unit for Nature & the Environment quality status A for models. MNP will be further developed and validated in the coming years

Natuurcombinaties en Europese natuurdoelen : ontwikkeling van een methode om natuurdoelen te realiseren buitenhet Natuurnetwerk Nederland

This study explored the possibilities for developing a method to determine what nature combinations outside Natura 2000 areas can contribute to the realisation of conservation objectives for Birds and Habitats Directive (BHD) species. A total of 54 species were selected that represent the BHD conservation objectives and for which the area outside the National Ecological Network is relevant; these are considered to be target species. For 43 of these species fiches were compiled containing a description of the most important habitat characteristics. An attempt was made to obtain a picture of the potential nature conservation effects of nature combinations related to conservation objectives. Using the ecological characteristics of the target species, an adapted version of the Model for Nature Policy (MNP) was developed to predict potential habitat from GIS information and the changes in habitat size and quality that can be brought about by nature combinations. An initial set of calculations was made for four species, limited to the eastern central region of the Netherlands. To obtain useful information it would appear necessary to have GIS data at a high level of spatial detail. Technically the model works and the first impression is that the results are ecologically plausible