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Context. Habitat loss is a global problem and in Fiji >50% of the land area once covered by forests has been converted to grasslands and agricultural land. About 99% of Fiji's endemic biodiversity and 80% of the land bird species have been identified as forest species. Aims. In this study, we compare forest and grassland sites and test for consistency in avian diversity, abundance, foraging guild, and distribution status (endemic, native, introduced to Fiji) over a 5-year period (2016-2020). Methods. We surveyed bird communities using the point count method with a 100 m radius and 7-min observation period per site. Key results. A one-way analysis of similarities (ANOSIM) analysis showed significant differences in species composition and bird abundance between the forested habitats and grassland habitats. A general linear model test showed significant differences in foraging guild composition and distribution status between forested and grassland habitats. There were no significant differences between the three forested sites (primary montane forest, secondary old-growth forest, old-growth mahogany plantations with regenerating native species), while grassland sites had stronger annual change in species composition. Implications. Forest cover, irrespective of whether these forests are of primary or secondary nature, therefore plays an important role in maintaining the native and endemic land bird species and other biodiversity in oceanic island ecosystems such as Viti Levu Island, Fiji. [ABSTRACT FROM AUTHOR]

Aim: The island species–area relationship (ISAR) assumes that the area of islands is homogeneous, or scales with environmental heterogeneity across an archipelago, which is not always the case. We compare the performance of models that adjust or substitute for island area with measures of habitat diversity, island age and resource availability for two taxonomic groups. Location: Five hotspot archipelagos (Azores, Galapagos, Hawaii, Cape Verde, Canary Islands). Taxa: Vascular plants, birds. Methods: We used the mathematical framework of the power law to compare relevant models, treating the one containing only area as a null model against which others were compared. Data were collated from databases and the literature. Models were compared using linear regression within archipelagos and via mixed effect models with archipelago as a random effect. Results: Weighting of island area by habitat diversity and resource availability systematically improved statistical significance and model fits versus the area only power law. Models including island age did not show the same systematic improvement in model fits. For vascular plants, weighting islands by resource availability (energy and water) performed better than weighting by habitat diversity, although for birds these weightings performed equally well. Main Conclusions: Given that islands within archipelagos are fairly heterogeneous in climate, topography and geology, it is worth accounting for this in ISARs. Our results suggest that, for islands in volcanic hotspot archipelagos, this is best done by using direct measures of habitat diversity and resource availability rather than using island age as a proxy. We, therefore, recommend using direct measures, rather than proxies, when investigating the drivers of biodiversity patterns on islands. [ABSTRACT FROM AUTHOR]

The importance of terrestrial coastal ecosystems for maintaining healthy coral reef ecosystems remains understudied. Sea kraits are amphibious snakes that require healthy coral reefs for foraging, but little is known about their requirements of terrestrial habitats, where they slough their skin, digest prey, and breed. Using concurrent microclimate measurements and behavior surveys, we show that a small, topographically flat atoll in Fiji with coastal forest provides many microhabitats that relate to the behaviors of Yellow Lipped Sea Kraits, Laticauda colubrina. Microclimates were significantly related to canopy cover, leaf litter depth, and distance from the high‐water mark (HWM). Sea kraits were almost exclusively observed in coastal forest within 30 m of the HWM. Sloughing of skins only occurred within crevices of mature or dying trees. Resting L. colubrina were significantly more likely to occur at locations with higher mean diurnal temperatures, lower leaf litter depths, and shorter distances from the HWM. On Leleuvia, behavior of L. colubrina therefore relates to environmental heterogeneity created by old‐growth coastal forests, particularly canopy cover and crevices in mature and dead tree trunks. The importance of healthy coastal habitats, both terrestrial and marine, for L. colubrina suggests it could be a good flagship species for advocating integrated land‐sea management. Furthermore, our study highlights the importance of coastal forests and topographically flat atolls for biodiversity conservation. Effective conservation management of amphibious species that utilize land‐ and seascapes is therefore likely to require a holistic approach that incorporates connectivity among ecosystems and environmental heterogeneity at all relevant scales. [ABSTRACT FROM AUTHOR]

Understanding how species diversity is related to sampling area and spatial scale is central to ecology and biogeography. Small islands and small sampling units support fewer species than larger ones. However, the factors influencing species richness may not be consistent across scales. Richness at local scales is primarily affected by small‐scale environmental factors, stochasticity and the richness at the island scale. Richness at whole‐island scale, however, is usually strongly related to island area, isolation and habitat diversity. Despite these contrasting drivers at local and island scales, island species–area relationships (SARs) are often constructed based on richness sampled at the local scale. Whether local scale samples adequately predict richness at the island scale and how local scale samples influence the island SAR remains poorly understood. We investigated the effects of different sampling scales on the SAR of trees on 60 small islands in the Raja Ampat archipelago (Indonesia) using standardised transects and a hierarchically nested sampling design. We compared species richness at different grain sizes ranging from single (sub)transects to whole islands and tested whether the shape of the SAR changed with sampling scale. We then determined the importance of island area, isolation, shape and habitat quality at each scale on species richness. We found strong support for scale dependency of the SAR. The SAR changed from exponential shape at local sampling scales to sigmoidal shape at the island scale indicating variation of species richness independent of area for small islands and hence the presence of a small‐island effect. Island area was the most important variable explaining species richness at all scales, but habitat quality was also important at local scales. We conclude that the SAR and drivers of species richness are influenced by sampling scale, and that the sampling design for assessing the island SARs therefore requires careful consideration. [ABSTRACT FROM AUTHOR]

Determining patterns of plant diversity on granite inselbergs is an important task for conservation biogeography due to mounting threats. However, beyond the tropics there are relatively few quantitative studies of floristic diversity, or consideration of these patterns and their environmental, biogeographic, and historical correlates for conservation. We sought to contribute broader understanding of global patterns of species diversity on granite inselbergs and inform biodiversity conservation in the globally significant Southwest Australian Floristic Region (SWAFR). We surveyed floristics from 16 inselbergs (478 plots) across the climate gradient of the SWAFR stratified into three major habitats on each outcrop. We recorded 1,060 species from 92 families. At the plot level, local soil and topographic variables affecting aridity were correlated with species richness in herbaceous (HO) and woody vegetation (WO) of soil‐filled depressions, but not in woody vegetation on deeper soils at the base of outcrops (WOB). At the outcrop level, bioclimatic variables affecting aridity were correlated with species richness in two habitats (WO and WOB) but, contrary to predictions from island biogeography, were not correlated with inselberg area and isolation in any of the three habitats. Species turnover in each of the three habitats was also influenced by aridity, being correlated with bioclimatic variables and with interplot geographic distance, and for HO and WO habitats with local site variables. At the outcrop level, species replacement was the dominant component of species turnover in each of the three habitats, consistent with expectations for long‐term stable landscapes. Our results therefore highlight high species diversity and turnover associated with granite outcrop flora. Hence, effective conservation strategies will need to focus on protecting multiple inselbergs across the entire climate gradient of the region. [ABSTRACT FROM AUTHOR]

Background Refugia are island-like habitats that are linked to long-term environmental stability and, as a result, high endemism. Conservation of refugia and endemism hotspots should be based on a deep ecological and evolutionary understanding of their functioning, which remains limited. Although functional traits can provide such insights, a corresponding, coherent framework is lacking. Proposed Framework Plant communities in refugia and endemism hotspots should, due to long-term environmental stability, display unique functional characteristics linked to distinct phylogenetic patterns. Therefore, such communities should be characterized by a functional signature that exhibits: (1) distinct values and combinations of traits, (2) higher functional diversity and (3) a prevalence of similar traits belonging to more distantly related lineages inside, compared to outside, of endemism hotspots and refugia. While the limited functional trait data available from refugia and endemism hotspots do not allow these predictions to be tested rigorously, three potential applications of the functional signature in biogeography and conservation planning are highlighted. Firstly, it allows the functional characteristics of endemism hotspots and refugia to be identified. Secondly, the strength of the functional signature can be compared among these entities, and with the surrounding landscape, to provide an estimate of the capacity of endemism hotspots and refugia to buffer environmental changes. Finally, the pattern of the functional signature can reveal ecological and evolutionary processes driving community assembly and functioning, which can assist in predicting the effect of environmental changes (e.g. climate, land-use) on communities in endemism hotspots and refugia. Conclusion The proposed functional signature concept allows the systematic integration of plant functional traits and phylogeny into the study of endemism hotspots and refugia, but more data on functional traits in these entities are urgently needed. Overcoming this limitation would facilitate rigorous testing of the proposed predictions for the functional signature, advancing the eco-evolutionary understanding of endemism hotspots and refugia. [ABSTRACT FROM AUTHOR]

Tree hollows constitute crucial habitats for fauna and can buffer ambient environmental conditions. The latter property should be especially relevant during extreme weather conditions, which are forecast to increase under anthropogenic climate change. We investigated the buffering capacity of Eucalyptus oleosa F.Muell. ex Miq. subsp. oleosa tree hollows in semi-arid southern Australia for 28 days under a wide range of ambient temperatures. Tree hollows provided more stable microclimates than ambient conditions, maintaining lower temperatures and higher humidity during the day and higher temperatures and lower humidity during the night. Daytime buffering capacity increased slightly with depth and we recorded a maximum buffering of 15.1°C below ambient temperatures. Maximum day time buffering capacity increased at a rate of approximately 0.6°C per 1°C increase in ambient temperature, meaning that maximum buffering capacity was reached during the hottest periods. The high buffering capacity of tree hollows suggests that old trees with deep hollows are important in facilitating the persistence of fauna during extreme weather events. Therefore, protecting old-growth forests and vegetation remnants that are rich in tree hollows is an important strategy for mitigating the impact of climate change on fauna. [ABSTRACT FROM AUTHOR]

Aim Granite outcrops may be able to act as refugia for species during adverse climate change, owing to their topographic complexity. We assessed this hypothesis by examining phylogeographical patterns in a common, geographically widespread granite endemic, Stypandra glauca (Hemerocallidaceae). Location Granite outcrops of the Southwest Australian Floristic Region, Western Australia. Methods Twenty-four tetraploid individuals of the granite endemic Stypandra glauca were sampled from each of 12 granite outcrops: 7 from a mesic environment and 5 from the semi-arid region. Phylogenetic reconstruction and divergence-dating was achieved using Bayesian and parsimony analyses of chloroplast haplotypes from 90 individuals. Nuclear diversity and population differentiation were analysed across all individuals using 10 microsatellite loci. Results Stypandra glauca exhibited high (chloroplast) or moderate (nuclear) levels of divergence among, and low diversity within, outcrops. Haplotype diversity was high in both sampling regions, and each haplotype was unique to one outcrop. There was little correlation between geographical and genetic distance. Both nuclear and chloroplast diversity were higher in southern (mesic) outcrops than in northern (semi-arid) outcrops, although the level of chloroplast divergence among outcrops was similar for both climatic regions. Main conclusions The levels of divergence and low diversity revealed in S. glauca support a scenario of prolonged isolation and persistence on granite outcrops in both mesic and semi-arid climatic regions, with no evidence of contraction-expansion dynamics across the outcrop network. The higher levels of diversity in the southern populations may result from the maintenance of a larger effective population size in southern regions, which retained more mesic climates during drier glacial periods. Although the climatic conditions differ between outcrops in this study, our results indicate that outcrops in both regions have harboured S. glauca throughout climatic changes, accentuating the value of these habitats to biodiversity conservation under future changing climate. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim Identifying and protecting refugia is a priority for conservation under projected anthropogenic climate change, because of their demonstrated ability to facilitate the survival of biota under adverse conditions. Refugia are habitats that components of biodiversity retreat to, persist in and can potentially expand from under changing environmental conditions. However, the study and discussion of refugia has often been ad hoc and descriptive in nature. We therefore: (1) provide a habitat-based concept of refugia, and (2) evaluate methods for the identification of refugia. Location Global. Methods We present a simple conceptual framework for refugia and examine the factors that describe them. We then demonstrate how different disciplines are contributing to our understanding of refugia, and the tools that they provide for identifying and quantifying refugia. Results Current understanding of refugia is largely based on Quaternary phylogeographic studies on organisms in North America and Europe during significant temperature fluctuations. This has resulted in gaps in our understanding of refugia, particularly when attempting to apply current theory to forecast anthropogenic climate change. Refugia are environmental habitats with space and time dimensions that operate on evolutionary time-scales and have facilitated the survival of biota under changing environmental conditions for millennia. Therefore, they offer the best chances for survival under climate change for many taxa, making their identification important for conservation under anthropogenic climate change. Several methods from various disciplines provide viable options for achieving this goal. Main conclusions The framework developed for refugia allows the identification and description of refugia in any environment. Various methods provide important contributions but each is limited in scope; urging a more integrated approach to identify, define and conserve refugia. Such an approach will facilitate better understanding of refugia and their capacity to act as safe havens under projected anthropogenic climate change. [ABSTRACT FROM AUTHOR]

We review the threats from anthropogenic climate change to the terrestrial biodiversity of Oceania, and quantify decline in carbon stocks. Oceania's rich terrestrial biodiversity is facing unprecedented threats through the interaction of pervasive environmental threats (deforestation and degradation; introduced and invasive species; fragmentation) and the effects of anthropogenic climate change (sea level rise; altered rainfall patterns and increased fire frequency; temperature rises and increased storm severity, extreme weather events and abrupt system changes). All nine of Oceania's terrestrial biomes harbour ecosystems and habitat types that are highly vulnerable under climate change, posing an immense conservation challenge. Current policies and management practices are inadequate and the need for new legislation and economic mechanisms is clear, despite powerful interests committed to limiting progress. Mitigation can be achieved by increasing the effectiveness of the protected area network, by maintaining and effectively managing existing carbon stocks and biodiversity, and by reforestation to sequester atmospheric carbon. A price on carbon emissions may encourage less carbon-intensive energy use while simultaneously encouraging reforestation on long-cleared land, and reducing degradation of native forests. However, realizing these changes will require societal change, and depend on input and collaboration from multiple stakeholders to devise and engage in shared, responsible management. [ABSTRACT FROM AUTHOR]

Tropical dry forests are a unique and threatened ecosystem in the Pacific and globally. In Fiji, the endangered Fijian crested iguana (Brachylophus vitiensis) is endemic to tropical dry forests. Yadua Taba Island contains one of the best remaining stands of tropical dry forest in the Pacific along with the largest (and only secure) population of B. vitiensis in Fiji and has been proposed as a translocation source for iguana conservation. In this study we determined the major vegetation types on Yadua Taba and identified forest habitat preferences of B. vitiensis to (1) characterize the island's habitats for tropical dry forest regeneration monitoring and (2) understand which forest types are preferred by iguanas for future translocation projects. Vegetation data were collected using reconnaissance, entitation, line transects, and aerial photos. Iguana abundance data were collected by nocturnal surveys of permanent transects. Six major vegetation types were identified of which tropical dry forest was the largest (46% of the island), followed by a combination of rocky cliff-shrubland/grassland vegetation (26%). Our conservative estimate of B. vitiensis population size on Yadua Taba is 12,000 iguanas, the majority of which occur in tropical dry forest. Superabundance of the dry forest understory tree Vavaea amicorum, the favorite fruit species of iguanas, may help account for the high density of iguanas observed. These results highlight the ecological link between tropical dry forest and B. vitiensis and emphasize the importance of rehabilitation or conservation of tropical dry forest habitat in potential iguana translocation sites as part of the management plan for B. vitiensis throughout the Fiji Islands. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented regarding the refugia as a key to climatic change management.