Institute for Biodiversity and Ecosystem Dynamics

IBED scientists test new theory to explain declining biodiversity

3 October 2011

Paul van Rijn and Maurice Sabelis of the Institute for Biodiversity and Ecosystem Dynamics (IBED) acquired a grant from the ‘Biodiversity Works’ programme of the Netherlands Organisation for Scientific Research (NWO) to explore concepts and mechanisms to explain biodiversity and related ecosystem services that are still little used in landscape ecology and nature conservation, but are thought to be of significant importance.

Paul van Rijn and Maurice Sabelis of the Institute for Biodiversity and Ecosystem Dynamics (IBED) acquired a grant from the ‘Biodiversity Works’ programme of the Netherlands Organisation for Scientific Research (NWO) to explore concepts and mechanisms to explain biodiversity and related ecosystem services that are still little used in landscape ecology and nature conservation, but are thought to be of significant importance.

Biodiversity is declining, in dedicated nature reserves as well in agriculture-dominated landscapes. Many projects aiming at halting this decline have yielded less than satisfying results. In agriculture this biodiversity loss is associated with loss in ecosystem services such as pollination and natural pest suppression. Our understanding of how biodiversity arises and is maintained is still limited. Landscape complementation is a poorly recognized, but potentially important element for building new theory. It is based on the observation that some species require different resources during their life history which are not all present in one and the same habitat year round. The presence of various ‘complementary’ habitats within the dispersal or foraging range is thus essential for the survival of individuals and the persistence of populations. Although this concept is well-known among e.g. herpetologists and ornithologists it is not much used in landscape ecology and has, as yet, limited impact on nature conservation policies.

The main objective of the new research project of Van Rijn and Sabelis is to formalize the complementary habitat theory, and to demonstrate its power in predicting the impact of landscape structure on biodiversity and ecosystem services. Their research will focus on well-studied natural enemies of aphids and other insect pests. Many insects responsible for natural pest suppression (such as hoverflies and lacewings) have diets as juveniles that differ from those of adults. While the larvae can often find their prey within annual crops, the adults need to move to field margins or other non-crop habitats to find the floral resources they feed on. In autumn, winter and spring arborous habitats are required to provide food and shelter. Consequently, individuals have to move from habitat to habitat depending on their life stage, their feeding condition and the spatio-temporal availability of resources. The impact of habitat configuration on population persistence and prey suppression will be analyzed by stage- and habitat-structured population models specified for these species. The models will be validated by comparing their predictions with data on species distributions.

By applying landscape population modeling to key natural enemies of pests, Van Rijn and Sabelis hope to provide tools and measures to improve the natural control op pests in agricultural landscapes in a cost-effective way. Such measures may also indirectly increase local biodiversity due to a reduced need to apply pesticides. Moreover, it may provide an economic basis for the conservation and restoration of semi-natural landscape elements within agriculture dominated landscapes. This may contribute to the acceptance by farmers as well as the general public for investments to improve the landscape.

Biodiversity Works

The ‘Biodiversity Works’ programme of NWO is targeted programme aimed at generating new knowledge for the policy subjects: i) more attention for dynamic nature, ii) ecosystem functions and services, and iii) how to deal with scarcity of space for nature. The funding provided will be used to employ a PostDoc researcher with IBED for a period of three years. The study at the research group Population Biology will be performed in collaboration with the IBED research groups of Theoretical Ecology (André de Roos) and Computational Geo-Ecology (Emiel van Loon).

Published by  IBED