Institute of Systematics, Evolution and Biodiversity, CNRS/MNHN, France Coordinator: Michel Baguette
Evolutionary Ecology Group, University of Wurzburg, Germany
Institute of Biology and Environmental Sciences, University of Aberdeen, UK
Experimental Ecology Centre of Moulis, CNRS, France
In a context of rapid global change, habitat loss and fragmentation are considered one of the main drivers of biodiversity loss, with numerous effects on ecosystems. To counter these effects, some conservation strategies explicitly focus on the improvement of landscape connectivity (between local patches of biodiversity) and the establishment of ecological networks that should allow organisms to move among different habitats and populations. The functionality of these networks, however, has rarely been tested, due to the complexity of determinants of its efficiency. The TenLamas project aimed at:
1. Evaluating different models of the functionality of ecological networks aiming at linking isolated populations in fragmented landscapes and assessing the relevance of several connectivity estimates;
2. Comparing different scenarios of landscape structures to investigate implications for population connectivity.
To respond to this challenge, the TenLamas team focused on model species (lizards, toads, birds and butterflies) in test landscapes in France and Germany and one in Africa for which they had long-term data on population dynamics. They compared three different methods to estimate connectivity (simple structural connectivity, least-cost paths, and individual-based models of animal movements). Each method’s predictions were compared to measures of effective dispersal by looking at the genetic structure of interconnected local populations. The final objective was to assess the reliability of each of these methods for estimating the extinction probability of the target populations.
• TheTenLamasteamdevelopedtwosophisticated movement and dispersal modelling packages (SMS – Stochastic Movement Simulator; and RandomWalker) and demonstrated that accounting for cognitive decision processes in movements is important for the assessment of dispersal and connectivity.
• The team showed that one modelling approach (structural methods) works well for studied butterflies, while another (individual-based models) is more suitable for studied toads. This shows that best-suited tools depend on species.
• TenLamas demonstrated that spatial genetic data can be used to test and compare different movement models, which would be straightforward and faster compared to present methods based on the direct records of animals by movement tracking or capture-mark-recapture experiments.
• The project also demonstrated the robustness of dispersal distance predictions based on life history traits for butterflies. This original result has been now extended to other taxa (plants, vertebrates) by other teams, showing the importance of this procedure because dispersal distance predictions are regularly missing from population viability studies, which has important implications for conservation planning decisions.
TenLamas provided evidence that it should be possible to use genetic methods combined with mechanistic movement and dispersal models to assess the efficiency of connectivity and ecological networks for species conservation .
The TenLamas team reviewed whether landscape connectivity estimates could gain in precision and generality by incorporating fundamental outcomes of dispersal theory. It proposed a 5-step approach* (see Figure) for the design of ecological networks allowing multi-species conservation actions, using genetic and dispersal modelling tools to assess linkages and dispersal ability among populations for different umbrella species.
* Baguette et al. (2013) Individual dispersal, landscape connectivity and ecological networks, Biological Reviews 88: 310-326
• In France, the TenLamas coordinator worked with the Ministry of ecology as part of an ad hoc expert group on connectivity issues.
• TenLamas also fostered close links with the French natural heritage service in charge of deploying the ecological networks. They were involved in the scientific council and the service also actively communicated about TenLamas, helping to disseminate the project’s results.
• In the UK, TenLamas engaged with the government scientific advisory agency whose representatives were kept informed on project results and regularly participated to project meetings. They notably participated to disseminating new knowledge and insights on how to assess ecological networks in the organisation.
• TenLamas also allowed to build lasting relationships with the project’s stakeholders and lead to the funding of new projects in collaboration with several of them.
• Orientation documents of the French Service for the Protection of Nature: TenLamas members directly contributed to two orientation documents of the authority in charge of implementing the French ecological network aiming at proposing test procedures of its efficiency.
• SMS software and collaboration with TerrOïko (http://www.terroiko.fr/): in 2012, a former TenLamas student launched a start-up company in ecological engineering, applying novel technologies to environmental issues. Part of their evaluation tools are based on the TenLamas Stochastic Movement Simulator (SMS), which is an original individual-based model for predicting the movements of dispersing animals between breeding habitat patches through a heterogeneous landscape.