Multiple analyses redirect management and restoration priorities for a critically endangered ecological community

Abstract

Accurately assessing community diversity patterns across distributional ranges is critically important for informed and effective management of ecological communities. Yet, for many wide‐ranging communities diversity patterns across broad ranges are poorly known. We apply a range of analytical approaches to an extensively studied ecological community to determine the relative utility and complementarity of these analytical approaches and their applicability for improved management. White Box Yellow Box Blakely’s Red Gum Woodland (herein abbreviated to BGW) occurs across seven bioregions in New South Wales, eastern Australia. Previous work has suggested either small levels of regional variation in floristic patterns or, contrastingly, up to ~80 variants determined by expert‐driven assessment. We undertook floristic survey and analysed floristic patterns using multivariate dispersion, diversity metrics (alpha (α) diversity, beta (β) diversity, gamma (γ) diversity and zeta (ζ) diversity; including assessments of β turnover and nestedness and higher order ζ diversity). Expert‐derived BGW variants were not clearly related to patterns of floristic variation. In this study, multivariate interactions were critical to identifying patterns of floristic variation. ζ diversity provided insights into bioregional variation not detected via other analytics and was more robust to unbalanced data than β diversity. However, β diversity provided important insights, detecting changing community patterns within a bioregion that would otherwise not be detected and allowing for some comparison of our results with other studies. This study highlights the value of applying multiple analytical approaches to the understanding of floristic patterns. Conservation of floristic diversity in BGW requires protection and management across its range, something which has not previously been adequately addressed.

Linking restoration to the IUCN red list for ecosystems: A case study of how we might track the Earth's ecosystems

“…69% of species in Tierney et al. 2021). Therefore this site‐based assessment of ground layer plant species diversity was related to available woody extent mapping (NSW Native Vegetation Extent 5 m Raster v1.2 ‐ Fisher et al.…”

“…The total area of extant BGW in NSW was then calculated and the accuracy of this area assessed via a further 104 randomly generated rapid survey points (surveyed 4/1/21 to 17/2/21). All surveys for this study and Tierney (2021) were undertaken under drought conditions ensuring uniform conditions for assessment and providing an assessment cued to detect the most resilient species. However, transitory increases in some species, particularly exotic annuals, can be expected under other conditions.…”

“…To assess whether site condition can be estimated from a remote sensed layer of tree cover, condition assessments were generated for 204 400 m 2 (square) plots (100 plots available from Tierney et al. 2021 and the additional 104 plots undertaken for validation of the extant map). For each of these plots ground layer native plant species diversity was scored as high (<5% exotic species cover), low (>95% exotic species cover) or moderate (all other sites) after at least a 10 min.…”

“…Mapping for BGW across its range from a previous study (Tierney et al 2021) was updated to include previously unmapped BGW within this range (referred herein as the Currently BGW is CR (Critically Endangered) and downgrading of extinction risk requires moving to EN (Endangered) for both Criteria A and D of IUCN (2016) and a potential long-term goal of further reducing risk to VU (Vulnerable) also shown. Risk and recovery for Criterion A is defined by geographic distribution.…”

“…2; Tierney et al. 2021 with updated data available in http://seed.nsw.gov). An RLE risk assessment for BGW (NSW Threatened Species Scientific Committee 2020) was used to identify the most important recovery actions required to reduce ecosystem risk.…”