Conservation of biodiversity associated with old oaks Frida Wall Department of Biology – IFM Linköping University

Aims 1.Work out a preservation strategy for flora and fauna associated with old oaks: a) Minimise the negative effects of habitat fragmentation at a landscape level. b) Develop a management strategy which aims at increasing the habitat quality at the tree/stand level and to ensure regeneration of old oaks. 2.Formulate general results regarding long term management strategies.

Ecological problem The organisms associated with old oaks are living in: 1.a habitat that change over time in a defined direction

Succession Old oaks’ successive stages: Stages according to hollow and amount of wood mould.

Ecological problem The organisms associated with old oaks are living in: 1.a habitat that change over time in a defined direction 2.landscapes with changing composition and configuration of habitat 3.a habitat that may have a high level of succession synchrony with other habitats in the same oak stand and/or the same landscape

Background Old oaks harbours a species-rich flora and fauna (lichens and beetles). The old oak habitats are very few today, and distributed in a heterogeneous landscape. The amount of old oaks has decreased severely. The longlived old oaks today have to be replaced with “new” old oaks in the future. The management strategies doesn’t include the long term landscape perspective. There is no strategy to ensure regeneration of old oaks at a landscape level.

Important factors Important factors:  Distance to other old oaks, and the amount of old oaks in a stand: Some saproxylic beetles seem to need stands with more than 10 old oaks (Ranius, 2002).  Species dispersal rate and shortest dispersal distance (colonisation rates).  Species’ generation time.  Shaded/unshaded habitats: There is a higher beetles species richness in sun-exposed trees (Ranius & Jansson, 2000).

How?  Construct a metapopulation model that includes spatial location and habitat quality of each stand: 1) without density dependence 2) with density dependence (population growth, dispersal)  Construct a model which treats each oak individually.

Data Oak inventory from the County Administration Board of Östergötland. In collaboration with other projects: Beetles data, mainly saproxylic beetles – Nicklas Jansson. Lichens data – Håkan Lettman Complementary field work (mainly oak data, for example borecore)

Data The County Administration Board: Oak inventory

Questions General questions The metapopulations are facing two parallel problems: synchrony among the habitats, and habitat succession. What effect on extinction risks has this?