Climate change and outdoor regional living plant collections: an example from mainland Portugal

Original PaperClimate change threatens not only plant species occurring naturally, but also impacts on regional living plant collections, which play an important role in ex situ conservation strategies. In the last few years, several global circulation models have been used to predict different global climate change scenarios. Due to their coarse resolutions, and while more detailed regional approaches are not available, downscaling techniques have been proposed, as a very simple first approach to increase detail. We analysed seven sites on mainland Portugal with potential for species conservation (four botanic gardens and three universities), in the light of downscaled climate change scenarios, using an environmental envelope approach and a predefined bioclimatic neighbourhood for each site. Thresholds for the bioclimatic neighbourhood were based on Rivas-Martı´nez’s Bioclimatic Classification of the Earth. For each site, the expected geographical shift of its original bioclimatic neighbourhood (1950–2000) was mapped for 2020, 2050 and 2080. Analysing those shifts enabled us to delineate knowledge-transfer paths between sites, according to the analysed scenarios. We concluded that, according to the Intergovernmental Panel on Climate Change A2 scenario, all considered sites will be outside the predefined bioclimatic neighbourhood by 2080, while according to the B2 scenario all of them will be inside that neighbourhood, although sometimes marginally so. Therefore, the implementation of global sustainability measures as considered in the B2 scenario family can be of great importance in order to delay significantly the impacts of climate change, giving extra time for the adaptation of the outdoor regional living plant collectionsinfo:eu-repo/semantics/publishedVersio

Differential Response to Soil Salinity in Endangered Key Tree Cactus: Implications for Survival in a Changing Climate

Understanding reasons for biodiversity loss is essential for developing conservation and management strategies and is becoming increasingly urgent with climate change. Growing at elevations <1.4 m in the Florida Keys, USA, the endangered Key tree cactus (Pilosocereus robinii) experienced 84 percent loss of total stems from 1994 to 2007. The most severe losses of 99 and 88 percent stems occurred in the largest populations in the Lower Keys, where nine storms with high wind velocities and storm surges, occurred during this period. In contrast, three populations had substantial stem proliferation. To evaluate possible mortality factors related to changes in climate or forest structure, we examined habitat variables: soil salinity, elevation, canopy cover, and habitat structure near 16 dying or dead and 18 living plants growing in the Lower Keys. Soil salinity and elevation were the preliminary factors that discriminated live and dead plants. Soil salinity was 1.5 times greater, but elevation was 12 cm higher near dead plants than near live plants. However, distribution-wide stem loss was not significantly related to salinity or elevation. Controlled salinity trials indicated that salt tolerance to levels above 40 mM NaCl was related to maternal origin. Salt sensitive plants from the Lower Keys had less stem growth, lower root:shoot ratios, lower potassium: sodium ratios and lower recovery rate, but higher δ 13C than a salt tolerant lineage of unknown origin. Unraveling the genetic structure of salt tolerant and salt sensitive lineages in the Florida Keys will require further genetic tests. Worldwide rare species restricted to fragmented, low-elevation island habitats, with little or no connection to higher ground will face challenges from climate change-related factors. These great conservation challenges will require traditional conservation actions and possibly managed relocation that must be informed by studies such as these

Orchid re-introductions: an evaluation of success and ecological considerations using key comparative studies from Australia

With global biodiversity in decline, there is now an urgent requirement to take ameliorative action for endangered species in the form of reintroductions. For the highly diverse orchid family, many species face imminent extinction. Successful reintroductions that result in self-sustaining populations require not only an understanding of existing threats, but an in-depth understanding of species ecology. Increasingly, translocations, ranging from re-introductions to assisted colonisation, are being adopted as recovery actions. Do these translocations mitigate threatening processes and account for the two key ecological attributes for orchid survival; pollinator and mycorrhizal presence? Here, we conducted a literature review identifying the known threats to orchid survival and their necessary mitigation strategies. Next, we evaluated the success of 74 published international orchid translocations on 66 species against a consideration of orchid ecological attributes. Lastly, we empirically tested an additional 22 previously unpublished re-introductions on 12 species undertaken since 2007 against a re-introduction process that accounts for identified threats and orchid ecological attributes. We identified habitat destruction, weed invasion, herbivory, illegal collection, pollinator decline, pathogens and climate change as critical threats to orchid survival. In our global review based on published translocations, the average survival rate, 1-year post translocation was 66 % yet only 2.8 % of studies reported natural recruitment in field sites. Although survival of translocated orchids is clearly being achieved, these programmes did not relate orchid growth and development to key ecological requirements of orchid population resilience, pollinator and mycorrhizal ecology. Ensuring pollinator and mycorrhizal presence shows that these two factors alone are key factors influencing survival and persistence in an Australian review of 22 previously unpublished orchid re-introductions. In the Australian review flowering in the year following, out-planting was observed for 81 % of the re-introductions with seed set occurring in 63 % of re-introductions within the length of the study. Recruitment was observed in 18 % of the Australian re-introduced populations indicating a degree of population resilience. As orchid re-introductions will be a major strategy for wild orchid conservation in the future, we present a framework for orchid re-introductions, including criteria for success. We recommend symbiotic propagation and, for specialised pollination syndromes, the study of pollinator interactions prior to site selection and re-introduction of plants