Methods for cross-scale species distribution modelling

Knowledge of how to combine information about environmental factors that determine species distributions across spatial scales is indispensable for effective conservation and management. Researchers have tested three methodological approaches to combine distributional and environmental data for Finnish butterflies. They found that using the best information available at each spatial scale for the development of species distribution models and combining the results by simple multiplication significantly increases the predictive ability. This study highlights the notable potential of multi-scale approaches and demonstrates that the search for environmental correlates with species’ distributions must not only be addressed at an appropriate spatial scale, but also should be combined across the spatial scales due to the inherent hierarchy of processes where the higher levels constrain the lower levels.

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Fragmented forests and grasslands: plant sensitivity to habitat loss

General ecological theory suggests that shrinking the size of a habitat and cutting it off from surrounding patches of similar habitat – known as isolation - will reduce the population size of plant species. Isolation, or fragmentation, is a common feature of European agricultural landscapes and reports suggest that just 0.4-1.1% of original grassland remains.

While some scientific studies have revealed the link between habitat size and population size in forests, the effect on grassland species is less clear. The sensitivity of forest plants also appears to vary between species, leading scientists to look more closely at the underlying reasons for this. However, it can be difficult to separate the effects of isolation and habitat size from deterioration in habitat quality, which may occur in response to the same disturbance, i.e. land use change.

A new study exploring the sensitivity of grassland and forest plants to decreasing habitat size and isolation in north-central Europe concludes that an irreversible shift in the most dominant plant species may already be underway in forests and grassland, where forests are more vulnerable than grasslands.

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