Designing landscapes for biodiversity under climate change: supplement report
Landscape design – the particular placement of areas devoted to restoration of native vegetation at landscape scales – is a primary approach to climate adaptation for biodiversity. It may facilitate the maintenance of larger populations and shifts in species distributions, both of which should help native species adjust to changing climates. However, it is unclear exactly how to design landscapes to best achieve these goals, particularly because future landscapes will involve changed land uses and distributions of native communities which may interact with landscape designs.
We investigated whether one or more current approaches to landscape design would be robust to future climates – would tend to improve the likelihood of persistence for native species (and decrease the likelihood of persistence for key invasive species) across a range of plausible futures. In the previous final report for this project (Doerr et al. 2013), we selected two case study landscapes in New South Wales and modelled 48 future landscapes for each which differed in future land uses and distributions of native vegetation communities. We applied three current approaches to landscape design plus controls for spatial planning and total amount of restoration to each of these future landscapes. We then used a metapopulation capacity model to evaluate the change in each landscape’s capacity to support viable populations of four native species groups and two invasive species. Finally, we analysed whether the change in metapopulation capacity across all future landscapes for all species was influenced by landscape design principles. We found no effect of detailed spatial placement of restoration projects on the change in metapopulation capacity of our future landscapes. Only our positive control – restoring landscapes to ~30% native vegetation cover – improved future landscapes relative to current landscapes. However, the invasive peppercorn tree (Schinus molle) showed the opposite pattern, becoming more problematic with landscape improvements for native species.
For this supplementary report, we performed additional analyses to validate these results using a third case study landscape, the area managed by the Wimmera Catchment Management Authority in Victoria. The Wimmera was selected because it has an overall drier climate, somewhat different vegetation types, smaller total area, and slightly different vegetation types. These differences allowed us to evaluate whether our conclusions from the previous two case study landscapes were potentially dependent on local factors and specific model inputs, or whether they are truly generally applicable.
We found that our original conclusions are still valid – that only our positive control (restoring landscapes to ~30% native vegetation cover) improved future landscapes relative to current landscapes. The only difference was that the results for the Wimmera study landscape showed weaker patterns. We suggest this was due to the specific vegetation types present in the Wimmera but also the fact that land-use changes projected for the Wimmera involved less loss of native vegetation, particularly in the form of scattered trees. This strengthens our suggestion that spatial planning of changes in productive land uses may provide an additional management lever for biodiversity that is currently underutilised.
Please cite this supplement report as:
Doerr, VAJ, Williams, KJ, Drielsma, M, Doerr, ED, Davies, MJ, Love, J, Langston, A, Low Choy, S, Manion, G, Cawsey, EM, McGinness, HM, Jovanovic, T, Crawford, D, Austin, M & Ferrier, S 2013, Designing landscapes for biodiversity under climate change: A validation. The architecture of resilient landscapes: scenario modelling to reveal best-practice landscape design principles. Supplementary report to ‘Designing landscapes for biodiversity under climate change’, National Climate Change Adaptation Research Facility, Gold Coast, 80 pp.
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