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Thermal adaptation to habitat variability can determine species vulnerability to environmental change. For example, physiological tolerance to naturally low thermal variation in tropical forests species may alter their vulnerability to climate change impacts, compared with open habitat species. However, the extent to which habitat-specific differences in tolerance derive from within-generation versus across-generation ecological or evolutionary processes are not well characterized. Here we studied thermal tolerance limits of a Central African butterfly (Bicyclus dorothea) across two habitats in Cameroon: a thermally stable tropical forest and the more variable ecotone between rainforest and savanna. Second generation individuals originating from the ecotone, reared under conditions common to both populations, exhibited higher upper thermal limits (CTmax) than individuals originating from forest (∼3°C greater). Lower thermal limits (CTmin) were also slightly lower for the ecotone populations (∼1°C). Our results are suggestive of local adaptation driving habitat-specific differences in thermal tolerance (especially CTmax) that hold across generations. Such habitat-specific thermal limits may be widespread for tropical ectotherms and could affect species vulnerability to environmental change. However, microclimate and within-generation developmental processes (e.g. plasticity) will mediate these differences, and determining the fitness consequences of thermal variation for ecotone and rainforest species will require continued study of both within-generation and across-generation eco-evolutionary processes. This article has an associated First Person interview with the first author of the paper., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2021. Published by The Company of Biologists Ltd.)

The recently introduced bivalve Xenostrobus securis and the previously introduced Mytilopsis sallei (~30years) are dominant over the native Brachidontes variabilis in estuarine fouling communities in Hong Kong. This study tested whether these introduced species have higher thermal and salinity tolerance than the native species under local subtropical seawater conditions. Survival, attachment, clearance rate and byssal thread production of these three species were examined through 96-h acute temperature and salinity tests. The results indicated that X. securis responded normally over a wide range of temperature and salinity conditions. Though M. sallei exhibited a wide salinity tolerance, its sub-lethal responses decreased in cold-seawater conditions. Brachidontes variabilis had the narrowest tolerance to temperature and salinity. These findings may explain the dominance of the non-native bivalves over B. variabilis. The high tolerance of X. securis enables them to become highly invasive in subtropical regions across Southeast Asia, impacting natural communities and shellfish farming., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Climate change is driving a pervasive global redistribution of the planet's species. Species redistribution poses new questions for the study of ecosystems, conservation science and human societies that require a coordinated and integrated approach. Here we review recent progress, key gaps and strategic directions in this nascent research area, emphasising emerging themes in species redistribution biology, the importance of understanding underlying drivers and the need to anticipate novel outcomes of changes in species ranges. We highlight that species redistribution has manifest implications across multiple temporal and spatial scales and from genes to ecosystems. Understanding range shifts from ecological, physiological, genetic and biogeographical perspectives is essential for informing changing paradigms in conservation science and for designing conservation strategies that incorporate changing population connectivity and advance adaptation to climate change. Species redistributions present challenges for human well-being, environmental management and sustainable development. By synthesising recent approaches, theories and tools, our review establishes an interdisciplinary foundation for the development of future research on species redistribution. Specifically, we demonstrate how ecological, conservation and social research on species redistribution can best be achieved by working across disciplinary boundaries to develop and implement solutions to climate change challenges. Future studies should therefore integrate existing and complementary scientific frameworks while incorporating social science and human-centred approaches. Finally, we emphasise that the best science will not be useful unless more scientists engage with managers, policy makers and the public to develop responsible and socially acceptable options for the global challenges arising from species redistributions.

A major research question concerning global pelagic biodiversity remains unanswered: when did the apparent tropical biodiversity depression (i.e., bimodality of latitudinal diversity gradient [LDG]) begin? The bimodal LDG may be a consequence of recent ocean warming or of deep-time evolutionary speciation and extinction processes. Using rich fossil datasets of planktonic foraminifers, we show here that a unimodal (or only weakly bimodal) diversity gradient, with a plateau in the tropics, occurred during the last ice age and has since then developed into a bimodal gradient through species distribution shifts driven by postglacial ocean warming. The bimodal LDG likely emerged before the Anthropocene and industrialization, and perhaps ~15,000 y ago, indicating a strong environmental control of tropical diversity even before the start of anthropogenic warming. However, our model projections suggest that future anthropogenic warming further diminishes tropical pelagic diversity to a level not seen in millions of years. [ABSTRACT FROM AUTHOR]

Morphological traits can determine the ecological niches and performance of ectotherms and structure their distributions along environmental gradients. The thermal melanism hypothesis and Bergmann’s rule describe patterns of body colour luminance and body size along environmental gradients shaped by thermal influences on morphology. However, these patterns have rarely been investigated at the interspecific level for subtropical and tropical mountain environments. In this study, we sampled butterfly assemblages along elevations across three subtropical and tropical locations in China and examined how environmental factors affected body colour luminance and body size. We additionally reconstructed phylogenetic relationships among the sampled butterfly species and investigated morphology– elevation relationships within an evolutionary framework. Butterfly assemblages were consistently darker and larger at higher elevations across three replicate locations. Furthermore, based on a phylogenetic comparative analysis, we found that body colour luminance and body size of butterfly assemblages responded to elevation through both long-term processes and more recent environmental influences. Our findings support the thermal melanism hypothesis and Bergmann’s rule from diverse subtropical and tropical butterfly assemblages, indicating elevation may structure the distributions of tropical species through morphology. The thermal functions of morphology should therefore be considered when investigating species distribution patterns and responses to environmental changes. [ABSTRACT FROM AUTHOR]