The Consequences of Tree Diseases and Mitigation Options on Connectivity for Biodiversity

Background
Trees provide habitat for a unique subset of biodiversity but are currently under threat from a range of non-native pests and diseases. Trees are not only an important component of forests but also play an important role in the wider landscape (hedges, gardens and parks) where, critically, they provide connectivity between woods. This connectivity is threatened as trees die due to diseases and as local authorities remove infected trees to stop trees falling on roads and railways. The impact this loss of non-woodland trees has on biodiversity is unknown. Our work will address this key knowledge gap by making joint use of the state-of-the-art modelling platform, RangeShifter and newly compiled ecological data on ash- and oak-associated species (AshEcol and OakEcol, Mitchell et al., 2014) to simulate the impact of the loss of ash and oak trees (two tree species currently under threat in the UK) on biodiversity. RangeShifter is an individual-based population model (Bocedi et al., 2014) that can represent a range of ecological life histories and that models dispersal in substantially greater detail than previous software. Additionally it is straightforwardly coupled to environmental layers (e.g. produced from a GIS) in order to simulate spatial dynamics across real landscapes. AshEcol is a database of the 955 ash-associated species, their level of association with ash and information on whether they will or will not use any of 48 alternative tree species. We are currently collecting information on oak associated species (OakEcol) and this will be completed by 1st April 2017.

Objectives To test the following hypotheses
1. The impact of the loss of ash/oak on the movement of species will depend on their level of association with ash/oak. With the greatest impact on obligate species and the least impact on cosmopolitan species.
2. The success of mitigation will depend on a) where replacement trees are replanted, b) which tree species are planted, c) the lag time between trees being planted and reaching a suitable size/age to be utilized.
3. The extinction debt of species following tree removal from the landscape is often paid over decades, offering opportunities for long-term planning to prevent biodiversity loss.
4. Radio telemetry of moths can be used to substantially improve parameter estimation of the dispersal behaviour of understudied moth species and thus decrease levels of uncertainty associated with model outputs.