Connectivity conservation

Some woodland dependent plants and animals are highly mobile, able to move long distances to find suitable conditions or required resources. Given inherent variation in resource availability (whether water, nectar, insects or rodents), many woodland species are readily able to travel long distances—often through relatively inhospitable habitat—buffering populations against local shortages and short-terms periods of scarcity. This is most clearly demonstrated by birds and bats, two diverse groups that contain many woodland-dependent species. Studies from isolated remnants and longer-term studies measuring inter-annual variation across multiple sites have documented high levels of species turn-over in these groups pdf. This dynamism is driven by the comings and goings of species, prospecting across the landscape looking for particular resources.

While this has previously been considered in terms of demographic and genetic consequences for species persistence in relictual landscapes, the inherent mobility of many woodland species also has important implications for revegetation and restoration initiatives. Although adding to existing remnants will always be preferable, revegetation plots in green-field sites are visited by a large number of woodland species. If the new patch is big enough and contains sufficient resources, these visitors will stay for longer and may even breed. As well as providing recruits to arrest declining populations, the status of revegetated plots as habitat represents a much needed success story—just the sort of thing needed to inspire land-holders and management agencies to maintain their motivation and continue their efforts.

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 Although many woodland and forest dependent species are sufficiently mobile to colonise new or improved patches, many species are not and are effectively marooned in habitat remnants. Whether unable to move long distances or subject to predation outside woodland habitats, many reptiles, amphibians and small mammals can become stranded. This has two consequences. Firstly, those woodland remnants where a species persists soon contain more individuals than can be supported, leading to increased levels of density-dependent mortality and greater likelihood of local extinction. Secondly, once the population of a particular species has gone extinct within a particular patch, the woodland is unlikely to be recolonised in the future, even though it may contain all the resources needed by that species.

So, for a particular species in a given landscape, there may be too many individuals in some patches of decreasing quality and no individuals in patches of increasing quality. A short-term solution to this situation is targeted translocations—moving individual animals to unoccupied patches. Rather than willy-nilly, these actions would need to be carried out in an informed and carefully monitored manner. The Landcare movement has demonstrated the great willingness of landholders to repopulate their production-dominated properties with the plants that used to occur there—why not give them the opportunity to put some of the animals back as well?  More information about woodland conservation is summarized in a chapter of Temperate woodland conservation and management pdf.

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 As well as an area of ongoing research, my work on connectivity conservation is also applied directly to on-ground activities.  As a founding member of the Slopes to Summit partnership, I have helped prioritize areas for management through the Bushlinks program, assisting farmers while making lasting improvements to functional connectivity at the landscape scale.  As well as shoring up local populations of many woodland dependent species, these actions contribute to larger scale connectivity through the Great Eastern Ranges Initiative, safeguarding woodland and forest communities and minimizing future losses of species and functionality. 

 

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