Distributions of Earth's species are changing at accelerating rates, increasingly driven by human-mediated climate change. Such changes are already altering the composition of ecological communities, but beyond conservation of natural systems, how and why does this matter? We review evidence that climate-driven species redistribution at regional to global scales affects ecosystem functioning, human well-being, and the dynamics of climate change itself. Production of natural resources required for food security, patterns of disease transmission, and processes of carbon sequestration are all altered by changes in species distribution. Consideration of these effects of biodiversity redistribution is critical yet lacking in most mitigation and adaptation strategies, including the United Nation's Sustainable Development Goals.

Sex determination is a fundamental biological process, yet its mechanisms are remarkably diverse. In vertebrates, sex can be determined by inherited genetic factors or by the temperature experienced during embryonic development. However, the evolutionary causes of this diversity remain unknown. Here we show that live-bearing lizards at different climatic extremes of the species' distribution differ in their sex-determining mechanisms, with temperature-dependent sex determination in lowlands and genotypic sex determination in highlands. A theoretical model parameterized with field data accurately predicts this divergence in sex-determining systems and the consequence thereof for variation in cohort sex ratios among years. Furthermore, we show that divergent natural selection on sex determination across altitudes is caused by climatic effects on lizard life history and variation in the magnitude of between-year temperature fluctuations. Our results establish an adaptive explanation for intra-specific divergence in sex-determining systems driven by phenotypic plasticity and ecological selection, thereby providing a unifying framework for integrating the developmental, ecological and evolutionary basis for variation in vertebrate sex determination.

In mice and man, females prefer males with a major histocompatibility complex (MHC) genotype different to their own. We tested whether this phenomenon also occurs in the Swedish sand lizard (Lacerta agilis). Females in a laboratory experiment preferred to associate with odour samples obtained from more distantly related males at the MHC class 1 loci. Data on free-ranging lizards suggest that associations between males and females are nonrandom with respect to MHC genotype. However, male spatial distribution and mobility during the mating season suggest that the non-random pairing process in the wild may also be driven by corresponding genetic benefits to males pairing with less related females.

BackgroundTo date, the only estimate of the heritability of telomere length in wild populations comes from humans. Thus, there is a need for analysis of natural populations with respect to how telomeres evolve.Methodology/Principal FindingsHere, we show that telomere length is heritable in free-ranging sand lizards, Lacerta agilis. More importantly, heritability estimates analysed within, and contrasted between, the sexes are markedly different; son-sire heritability is much higher relative to daughter-dam heritability. We assess the effect of paternal age on Telomere Length (TL) and show that in this species, paternal age at conception is the best predictor of TL in sons. Neither paternal age per se at blood sampling for telomere screening, nor corresponding age in sons impact TL in sons. Processes maintaining telomere length are also associated with negative fitness effects, most notably by increasing the risk of cancer and show variation across different categories of individuals (e.g. males vs. females). We therefore tested whether TL influences offspring survival in their first year of life. Indeed such effects were present and independent of sex-biased offspring mortality and offspring malformations.Conclusions/SignificanceTL show differences in sex-specific heritability with implications for differences between the sexes with respect to ongoing telomere selection. Paternal age influences the length of telomeres in sons and longer telomeres enhance offspring survival.

Summary1. The effects of external conditions on embryonic development have been repeatedly examined in oviparous reptile species, but the effect of gestation conditions on offspring traits in viviparous species has rarely been examined. 2. The influence of maternal basking opportunities on gestation length and juvenile phenotype was investigated in a viviparous scincid lizard, Niveoscincus ocellatus . Females were housed under one of two experimental regimes (10 or 4 h access to basking) which reflected the natural variation in temperature, potentially one of the most important proximate sources of life-history variation. 3. Females with longer access to basking gave birth significantly earlier than those with reduced basking opportunities. Maternal access to basking significantly affected the phenotype and growth rate of her offspring. 4. Offspring born after relatively rapid development were longer, heavier and in better condition than offspring born after slower development. 5. In standard laboratory conditions, offspring born after rapid development grew more rapidly than those born after slower development, thus amplifying the difference in body size between these two groups postpartum. 6. These results suggest the existence of a strong selective pressure on female basking behaviour through the effect of the maternal environment on embryo development and offspring phenotype and highlight the role of temperature as a proximate source of variation in both the timing of reproductive events and in key life-history traits of neonates.

Sexual dimorphism is widespread in lizards, with the most consistently dimorphic traits being head size (males have larger heads) and trunk length (the distance between the front and hind legs is greater in females). These dimorphisms have generally been interpreted as follows: (1) large heads in males evolve through male-male rivalry (sexual selection); and (2) larger interlimb lengths in females provide space for more eggs (fecundity selection). In an Australian lizard (the snow skink, Niveoscincus microlepidotus), we found no evidence for ongoing selection on head size. Trunk length, however, was under positive fecundity selection in females and under negative sexual selection in males. Thus, fecundity selection and sexual selection work in concert to drive the evolution of sexual dimorphism in trunk length in snow skinks.

The immunocompetence^handicap hypothesis suggests that androgen-dependent male characters constitute honest signals of mate and/or rival quality because of the imposed costs through immune suppression associated with elevated testosterone levels. We demonstrate in a ¢eld experiment that male sand lizards (Lacerta agilis) exposed to elevated testosterone su¡ered from increased mass loss and tick load compared to control males. Although the ¢rst of these two results could be due to an elevated basal metabolic rate from increased plasma testosterone levels, the increased parasite load was statistically independent of the loss in body condition and is likely to be due to compromised immune function. Testosterone-treated males showed greater mobility than control males, and greater mobility resulted in higher mating success. Our experiment thus lends support to the immunocompetence^handicap hypothesis, suggesting that male testosterone levels have been moderated by balancing selection for reproductive success and sustained immune function.

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.