The spiny trapdoor spiders (Idiopidae) of the Cataxia bolganupensis-group from south-western Australia are revised, and six species are recognized: C. barrettae sp. nov., C. bolganupensis (Main, 1985), C. colesi sp. nov., C. melindae sp. nov., C. sandsorum sp. nov. and C. stirlingi (Main, 1985). All species exhibit extreme short-range endemism, with allopatric sky-island distributions in mesic montane habitats of the Stirling Range, Porongurup Range and Mount Manypeaks. A molecular phylogenetic analysis of mitochondrial cytochrome c oxidase subunit 1 (COl) and cytochrome b (CYB )sequences complements the morphological taxonomy, along with a key to species and detailed information on their distributions and habitat preferences. All six species are assessed as ‘endangered' using IUCN criteria, with the major threatening processes being the spread of the plant pathogenic fungus Phytophthora (causing dicback), climate change and inappropriate fire regimes.

Context Extrapolation of knowledge for threatened taxa between parts of their range that are disconnected and/or ecologically diverse can result in significant sources of error that undermine the effectiveness of conservation efforts. Aims We investigated the risks associated with extrapolation of ecological information across environmental gradients, using the quokka (Setonix brachyurus) as a case study. Information documented in the northern part of its range is currently used to manage this species across its range in south-western Australia. We examined the suitability of this approach by developing a habitat suitability model (HSM) for the quokka in the southernmost areas of its range and comparing this with existing knowledge for the species. Methods We surveyed 327 sites, representative of a range of ecotypes, for presence/absence of quokkas. Occupancy models were applied to select a subset of habitat variables that best predicted occupancy patterns. Key results Occupancy patterns were influenced by complex vegetation structure, low levels of woody debris and habitat patchiness. HSMs developed for quokkas in the north could not predict occupancy patterns in the south. Significant fragmentation of subpopulations was observed due to patchiness in the availability of suitable habitat. Conclusions The choice of predictor variables in HSMs that are not transferrable between regions could contribute to inappropriate management of habitat for quokkas and an increased risk of local extinctions. In addition, failure to consider processes that affect preferred habitat variables could contribute to the segregation of habitat patches and intervening distances that are too great for successful dispersal, immigration and recolonisation processes. Implications The extrapolation of HSMs between geographical areas can increase the risk of outcomes that are detrimental to the conservation of threatened species. Where such extrapolation is necessary, actions guided by the HSMs should be implemented in a management framework that can detect adverse effects, allow for inclusion of new ecological information and explicitly consider the limitations and assumptions of this approach. In addition, perceptions of habitat fragmentation need to include processes such as fire regimes and feral animals that affect the availability and connectivity of habitat and have the potential to adversely affect population viability.

Prescribed burning is frequently advocated as a means of managing habitat for threatened species. We studied effects of fire on the quokka (Setonix brachyurus), a species currently used as a focal species for planning prescribed burns in the southern forests of Western Australia. We examined (i) the recolonisation of burnt areas; (ii) the refuge value of unburnt vegetation; and (iii) fire prediction variables that may help to guide fire planning to achieve desired habitat management outcomes. We hypothesised that fire regimes promoting vegetation structure and patchiness of burnt and unburnt vegetation would result in more rapid recolonisation of burnt areas by quokkas. Occupancy modelling identified the most important variables for recolonisation as retention of vertical vegetation structure and multiple unburnt patches across >20% of the total area. These outcomes were associated with high surface moisture, low soil dryness and slow fire rates of spread. Intense wildfire resulted in complete loss of vegetation structure and a lack of unburnt patches, which contributed to these areas remaining uncolonised. Burning with high moisture differentials, maximising the effectiveness of edaphic barriers to fire, retaining unburnt vegetation and maintaining vegetation structure were found to be important elements of fire regimes in this region.

Context. An understanding of population size and status is necessary for the implementation of appropriate conservation measures to recover threatened taxa. Mark-recapture studies at large spatial scales are impractical and expensive and a rapid survey technique is an attractive option to provide a measure of relative abundance for cryptic species, using indicators of activity.Aims. The aim of our study was to use conventional methods for population estimation to calibrate a rapid survey technique for the quokka (Setonix brachyurus) in the southern forests of Western Australia, with a view to providing quantitative outcomes from this widely adopted monitoring approach.Methods. We evaluated the accuracy of relative abundances obtained from the rapid survey technique by comparing them with abundance estimates obtained through established methods for the estimation of populations, including web-based mark-recapture and transect-based counts of activity indicators and sightings.Key results. The rapid survey technique was effective at determining presence of quokkas but resulted in an overestimation of population size because of inaccurate assumptions about occupancy and relative abundance of animals. An alternative survey method based on counts of fresh faecal-pellet groups was found to provide a more reliable and practical estimation of population abundance (R 2 = 0.97). Conclusions. Activity indices can be used to quantify population abundance, but only for indicators of activity that can be detected readily and for which freshness of activity can be determined.Implications. Our findings suggest that a rapid survey based on activity indices can be used to evaluate quantitatively the population size of a species that is rare and potentially mobile at a landscape scale. The attraction of these techniques is that they provide a rapid and inexpensive survey option that is potentially applicable to any cryptic and/or threatened species and is practical for resource-constrained land managers.