Metapopulation Research Group Survival of species in fragmented forest landscapes Ilkka Hanski

Metapopulation Research Group Contents How to assess the consequences of fragmentation in dynamic landscapes? Time delay in metapopulation response to changing environment Extinction thresholds and implications for biodiversity conservation Conclusion: What is needed to protect biodiversity in our boreal forests?

fragmentation threatens biodiversity

Metapopulation Research Group How to estimate isolation and hence the effect of fragmentation? Isolation has a temporal as well as a spatial component --- current isolation versus how did that isolation evolve Solution: construct a model with which the occurrence of focal species in all parts of the landscape is predicted, including the focal fragments Simulate the occurrence of the species assuming the observed history of fragmentation

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Metapopulation Research Group Probability for a particular forest fragment to be occupied year Fragment 2 Fragment 9 Fragment 1 Fragment 5

Metapopulation Research Group Explaining the occurrence of four species of old- growth bracket fungi in spruce forest fragments Logistic regression model Isolation historyDecaying wood p p Amylocystis lapponica <0.001 <0.001 Fomitopsis rosea <0.001 Phlebia centrifuga <0.001 Cystostereum murraii Note! Current isolation nor time since isolation did not explain the occurrence of the species when analysed separately

Metapopulation Research Group message # 1 To understand a dynamic process, such as the effect of habitat fragmentation on biodiversity, it is helpful to employ a dynamic model

Metapopulation Research Group Metapopulation dynamics in dynamic landscapes How long is the delay in metapopulation response to change in landscape structure? Which factors influence the length of the time delay?

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Decline in the amount of habitat Metapopulation response: thick line = equilibrium thin lines = predicted changes

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common species species doomed to extinction

Metapopulation Research Group 1. Strength of the perturbation Transient time depends on three factors Short transient timeLong transient time

Metapopulation Research Group 2. Species and landscape specific turnover rate Transient time depends on three factors Short transient time Long transient time

Metapopulation Research Group 3. Distance to the extinction threshold Transient time depends on three factors Short transient time Long transient time Short transient time

Metapopulation Research Group message # 2 Time delay in metapopulation response to habitat loss and fragmentation is especially long in the case of the threatened species

Metapopulation Research Group Predicted change in the shape of the ‘commonness’ distribution following environmental change Number of species that have gone extinct Extinction debt = Number of species that will go extinct

Metapopulation Research Group Area of old-growth forest in Finland S Finland 0.6% N Finland 10.4% Entire Finland 5.5%

Metapopulation Research Group Threatened beetles in boreal forests (based on data and analysis by Pertti Rassi)

Metapopulation Research Group message # 3 Extinction debt in Finnish forests Based on the recent red data book, we may estimate that there are nearly 2,000 extinct or threatened species in Finnish forests In addition, there is a large and rapidly increasing number of regionally extinct or threatened species in southern Finland

Metapopulation Research Group The response of species to a change in habitat/landscape quality

Metapopulation Research Group Punttila, Siitonen & Lindström, julkaisematon

Metapopulation Research Group Punttila, Siitonen & Lindström, julkaisematon

Metapopulation Research Group The three-toed woodpecker - an example of the treshold condition at the regional scale

Metapopulation Research Group message # 4 The response of species to a change in habitat quality is typically non-linear and involves a threshold

Metapopulation Research Group The new forestry guidelines - is this the solution? If commercial forestry will occupy all the non-protected forest land, and if all this forested land will be managed according to the guidelines, the new guidelines may represent a change to the worse

Metapopulation Research Group The slow process of disappearence of endangered species in the current forest landscape

The outcome of comprehensive implementation of the new forestry practice

Let us focus the same conservation effort within 10% of forested land

Conservation measures within 10% of forested land but now located next to the currently most valuable forest stands

Metapopulation Research Group Concluding messages Our forests have a large extinction debt It is cost-effective to act now The new measures introduced in Finland (retention trees, protection of small patches of key habitats, etc.) may make the situation worse if all the forested land will be treated similarly It would pay to concentrate the conservation efforts… basically, we need more area out of commercial forestry