Does structural connectivity facilitate movement of native species in Australia's fragmented landscapes? A systematic review protocol

Background: Habitat fragmentation and accompanying isolation effects are among the biggest threats to global biodiversity. The goal of restoring connectivity to offset these threats has gained even greater urgency under the looming spectre of climate change. While linear corridors have been the most commonly proposed solution to these issues, it has become increasingly recognised that structural connectivity exists in different forms with a variety of characteristics. We previously conducted a systematic review from 2008-2010 to collate and synthesise evidence regarding the relationship between these different types of structural connectivity and the actual movement of native Australian plants and animals (i.e., functional connectivity). Our previous review produced a number of management recommendations but also identified significant knowledge gaps. Given that empirical research into connectivity has become even more common since the original review and that it has been more than five years since the original literature searches, the time is ripe for an update of that review. Methods: We will update our previous systematic review by repeating a thorough search for both published and unpublished evidence on the effects of structural connectivity on animal and plant movement through heterogeneous landscapes. We will slightly broaden the scope of the original review by including data on semi-aquatic species as well as terrestrial ones. Studies will be included if they: 1) contain data on a terrestrial or semi-aquatic native Australian species; 2) have at least one study site that contains some form of structural connectivity between otherwise isolated patches of habitat; and 3) include data on movement of species through the connectivity or data that allow inference of movement (or the lack thereof). We will repeat the analyses carried out for the original review which used hierarchical linear modelling to assess the effects of numerous sources of heterogeneity (e.g., type of connectivity, width of connection, ecosystem type, taxonomic group, and many other characteristics of the species, habitat, and connectivity) on the amount of movement observed in a landscape. If increased sample sizes allow we will also carry out additional meta-analyses, which were not possible with the original dataset.