Palau's rare and threatened palm Ponapea palauensis (Arecaceae): Population density, distribution, and threat assessment

Ponapea palauensis Kaneh., a palm endemic to the Palau archipelago in the western Caroline Islands, has previously been reported to be threatened and in decline due to predation by two species of introduced parrots, Cactua galerita Lath, and Eclectus roratus P. L. S. Mull., and potential predation by introduced rats. Here we assess its threatened status under the IUCN Red List Criteria and provide the first quantitative assessment of its population size. A complete distribution map is also provided establishing its total area of occupancy and maximum extent of occurrence. We find that the species qualifies for a minimum of Vulnerable status on the IUCN Red List, and it potentially qualifies for Critically Endangered status pending confirmation of a continuous population decline. Historical records of predation on the palms by parrots are consistent with current observations indicating that the species is threatened and in need of a management plan for conservation action and long-term monitoring of the stability of the extant population.Craig M. Costion, Ann Hillmann-Kitalong, Steve Perlman, and Will Edward

Using the ancient past for establishing current threat in poorly inventoried regions

The need for a global priority list for threatened plants has been widely recognized by the conservation community, yet the threatened status of the majority of the world’s plants species remains poorly known. This is especially true in the tropics and the oceanic islands of the Pacific, where progress towards the targets of the Global Strategy for Plant Conservation (GSPC) 2011–2020 is hindered by the paucity of complete species distribution data. Here we outline a new methodology to undertake threatened species assessments where detailed contemporary population data is lacking. This new interdisciplinary methodology draws upon the synthesis of archaeological and botanical data to calculate a percentage of long-term decline in habitat quality. We use this method to assess the threatened status of the endemic flora of Palau, Micronesia, a Pacific island nation known for its high levels of plant diversity and endemism, by utilizing data extending back to human colonization of the archipelago. For Palau, we calculate the percentage of a long-term decline in habitat quality to be 31–39% of the total available range of 55% of the endemic plant species. These data are also used to address a long debated question in the western Pacific: Are the origins of the savanna vegetation anthropogenic? Strong evidence for anthropogenic savannas in Micronesia support the estimated extent of historic deforestation in Palau. This new method worked well in our case study, and can be used in other locations with incomplete species distribution data to establish a first basis for conservation prioritization.Craig M. Costion, Jolie Liston, Ann H. Kitalong, Akiko Iida, Andrew J. Low

Filters of floristic exchange: How traits and climate shape the rain forest invasion of Sahul from Sunda

Aim: To evaluate how biogeographical and ecological processes influenced species distributions and community assembly in a continental rain forest flora with mixed biogeographical origins. Location: Continental Australia. Methods: We identified 795 species with Sahul ancestry (Australian rain forest flora of Gondwanan origin) and 604 species with Sunda ancestry (rain forest plant lineages of Indo-Malaysian origin) from a total of 1,872 free-standing Australian woody rain forest taxa. We then compared the distribution of Sunda to Sahul species in relation to variation in species richness and phylogenetic endemism at continental scale, and local species distributions in available plot data from the Tropics (Cape York and the Australian Wet Tropics in northern Queensland) and subtropics (Nightcap-Border Ranges, Washpool and Dorrigo, in northern New South Wales). We compared the dispersal and persistence characteristics, and key functional traits (leaf size, fruit size, wood density and maximum height at maturity) of the Sunda and Sahul components of the continental rain forest flora. The influence of climate (temperature) and local environmental (altitude) factors in driving fine-scale distributional patterns was evaluated. Results: Sunda rain forest species richness decreased with increasing latitude but maintained high levels of endemism, including in the south. Sunda species traits suggest more efficient dispersal and faster growth than Sahul lineages. Resprouting (persistence) was less evident in species with Sunda than Sahul ancestry. We show that Sunda lineage distributions were influenced by interacting environmental and climatic factors, as well as historical contingencies. Main conclusions: Efficient dispersal and relatively fast growth likely facilitated the establishment and spread of Sunda lineages in Australia. However, the Sunda invasion was resisted in stable, saturated communities of Sahul lineages, and in the temperate south where climate acted as a strong filter. The results highlight the importance of integrating historical biogeography and contemporary ecological processes to study continental-scale rain forest distribution and assembly. © 2018 John Wiley and Sons Lt

Filters of floristic exchange: How traits and climate shape the rain forest invasion of Sahul from Sunda

Aim: To evaluate how biogeographical and ecological processes influenced species distributions and community assembly in a continental rain forest flora with mixed biogeographical origins. Location: Continental Australia. Methods: We identified 795 species with Sahul ancestry (Australian rain forest flora of Gondwanan origin) and 604 species with Sunda ancestry (rain forest plant lineages of Indo-Malaysian origin) from a total of 1,872 free-standing Australian woody rain forest taxa. We then compared the distribution of Sunda to Sahul species in relation to variation in species richness and phylogenetic endemism at continental scale, and local species distributions in available plot data from the Tropics (Cape York and the Australian Wet Tropics in northern Queensland) and subtropics (Nightcap-Border Ranges, Washpool and Dorrigo, in northern New South Wales). We compared the dispersal and persistence characteristics, and key functional traits (leaf size, fruit size, wood density and maximum height at maturity) of the Sunda and Sahul components of the continental rain forest flora. The influence of climate (temperature) and local environmental (altitude) factors in driving fine-scale distributional patterns was evaluated. Results: Sunda rain forest species richness decreased with increasing latitude but maintained high levels of endemism, including in the south. Sunda species traits suggest more efficient dispersal and faster growth than Sahul lineages. Resprouting (persistence) was less evident in species with Sunda than Sahul ancestry. We show that Sunda lineage distributions were influenced by interacting environmental and climatic factors, as well as historical contingencies. Main conclusions: Efficient dispersal and relatively fast growth likely facilitated the establishment and spread of Sunda lineages in Australia. However, the Sunda invasion was resisted in stable, saturated communities of Sahul lineages, and in the temperate south where climate acted as a strong filter. The results highlight the importance of integrating historical biogeography and contemporary ecological processes to study continental-scale rain forest distribution and assembly. © 2018 John Wiley and Sons Lt

Continental-scale spatial phylogenetics of Australian angiosperms provides insights into ecology, evolution and conservation

Aim: Biodiversity studies typically use species, or more recently phylogenetic diversity (PD), as their analysis unit and produce a single map of observed diversity. However, observed biodiversity is not necessarily an indicator of significant biodiversity and therefore should not be used alone. By applying a small number of additional metrics to PD, with associated statistical tests, we can determine whether more or less of the phylogeny occurs in an area, whether branch lengths in an area are longer or shorter, and whether more long or short-branched endemism occurs in an area, than expected under a null model.\ud \ud Location: Australian continent.\ud \ud Methods: We used a phylogeny sampling 90% of Australia's angiosperm genera, and 3.4 million georeferenced plant specimens downloaded from Australia's Virtual Herbarium (AVH), to calculate PD, relative phylogenetic diversity (RPD) and relative phylogenetic endemism (RPE). Categorical analysis of neo- and palaeo-endemism (CANAPE) and randomization tests were performed to determine statistical significance.\ud \ud Results: We identify several combinations of significant PD and endemism across the continent that are not seen using observed diversity patterns alone. Joint interpretation of these combinations complements the previous interpretations of Australia's plant evolutionary history. Of conservation concern, only 42% of the significant endemism cells found here overlap with existing nature reserves.\ud \ud Main conclusions: These spatial phylogenetic methods are feasible to apply to a whole flora at the continental scale. Observed richness or PD is inadequate to fully understand the patterns of biodiversity. The combination of statistical tests applied here can be used to better explain biodiversity patterns and the evolutionary and ecological processes that have created them. The spatial phylogenetic methods used in this paper can be also be used to identify conservation priorities at any geographical scale or taxonomic level

Using phylogenetic diversity to identify ancient rain forest refugia and diversification zones in a biodiversity hotspot

Editor: Kerrie WilsonAIM The plight of the world’s biodiversity hotspots has been paralleled by a debate over how to best prioritize or maximize gain of biodiversity for conservation. Approaches to date have focused on quantifying species, habitat, phylogenetic or other types of diversity. The importance of preserving evolutionary distinctiveness or phylogenetic diversity (PD) has gained popularity due to its ability to identify evolutionary patterns in the landscape that traditional taxon richness measures cannot. Here, we expand upon the application of PD as a biodiversity index and incorporate data on historical biogeography to understand the processes that shaped the assembly of a tropical flora. LOCATION Tropical north-east Queensland, Australia. METHODS We generated a genus-level molecular phylogeny for the bioregion to calculate PD. We then integrated data on historical biogeography into a model to explain the distribution of PD and the PD residuals and further tested for a correlation between rain forest stability through time and community assembly. RESULTS We identified a strong correlation between PD residuals and the biogeographic origin of the lineages in the extant flora. Areas with higher PD than expected based on generic richness (GR) contain a higher proportion of immigrant plant lineages dispersed into northern Australia mostly from Southeast Asia within the past few million years. Areas with lower PD than predicted by genus richness are rich in ancient Australian relict lineages and are correlated with previously identified rain forest refugia that have remained stable throughout the last glacial cycle. MAIN CONCLUSIONS Maximizing PD without historical interpretation may yield unintended or undesirable conservation outcomes such as deprioritizing ancient refugia with lower PD values. By understanding the biome assembly of a region, better-informed decisions can be made to ensure different stages of a region’s evolutionary history are preserved.Craig M. Costion, Will Edwards, Andrew J. Ford, Daniel J. Metcalfe, Hugh B. Cross, Mark G. Harrington, James E. Richardson, David W. Hilbert, Andrew J. Lowe, and Darren M. Cray

Phylodiversity to inform conservation policy: An Australian example

Phylodiversity measures summarise the phylogenetic diversity patterns of groups of organisms. By using branches of the tree of life, rather than its tips (e.g., species), phylodiversity measures provide important additional information about biodiversit