Can changes in ant diversity along elevational gradients in tropical and subtropical Australian rainforests be used to detect a signal of past lowland biotic attrition?

Increasing temperatures are predicted to have profound effects on montane ecosystems. In tropical forests, biotic attrition may reduce lowland diversity if losses of species due to upslope range shifts are not matched by influxes of warmer‐adapted species, either because there are none or their dispersal is impeded. Australian rainforests consist of a north–south chain of patches, broken by dry corridors that are barriers to the dispersal of rainforest species. These rainforests have repeatedly contracted and expanded during Quaternary glacial cycles. Many lowland rainforests are expansions since the Last Glacial Maximum and may, therefore, show a signal of historical biotic attrition. We surveyed ants from replicated sites along three rainforest elevational transects in eastern Australia spanning 200 to 1200 m a.s.l. and nearly 14° of latitude. We examined elevational patterns of ant diversity and if there was possible evidence of lowland biotic attrition. Each transect was in a different biogeographic region; the Australian Wet Tropics (16.3°S), the central Queensland coast (21.1°S) and subtropical south‐eastern Queensland (28.1°S). We calculated ant species density (mean species per site) and species richness (estimated number of species by incorporating site‐to‐site species turnover) within elevational bands. Ant species density showed no signal of lowland attrition and was high at low and mid‐elevations and declined only at high elevations at all transects. Similarly, estimated species richness showed no evidence of lowland attrition in the Wet Tropics and subtropical south‐east Queensland; species richness peaked at low elevations and declined monotonically with increasing elevation. Persistence of lowland rainforest refugia in the Wet Tropics during the Last Glacial Maximum and latitudinal range shifts of ants in subtropical rainforests during the Holocene climatic optimum may have counteracted lowland biotic attrition. In central Queensland, however, estimated richness was similar in the lowlands and mid‐elevations, and few ant species were indicative of lower elevations. This may reflect historical biotic attrition due perhaps to a lack of lowland glacial refugia and the isolation of this region by a dry forest barrier to the north.     

Glacial and interglacial refugia within a long-term rainforest refugium: The Wet Tropics Bioregion of NE Queensland, Australia

An artificial neural network is used to classify environments, including climate, terrain and soil variables, according to their suitability for fifteen structural/environmental forest classes in the Wet Tropics Bioregion of north-east Queensland. We map the environments characteristic of these forest classes in four climate regimes (the present and three past climate scenarios), quantify the changes in area of these environments in response to past regional changes in climate and identify areas that would have been environmentally suitable for rainforests at last glacial maximum (glacial refugia). We also identify areas that would have been suitable for upland and highland rainforest classes during the warmest parts of the interglacial (interglacial refugia) and map locations that consistently remain favourable to specific forest classes despite large changes in climate.In the climate of the last glacial maximum (LGM), rainforest environments are predicted in three relatively distinct refugia in the northern, central and southern Wet Tropics. Only three percent of the total area contains lowland, Mesophyll Vine Forest and the majority of the area of the rainforest refugia supports upland rainforest classes. In the cool, wet climate of the Pleistocene/Holocene transition (PHT), rainforest environments expand to form a more or less continuous block from the northern limits of the region to the Walter Hill Range, except for discontinuous patches extending through the Seaview and Paluma Ranges in the south. During the Holocene climatic optimum (HCO), rainforest environments become more fragmented, especially in the south. Lowland rainforest environments are very extensive in this climate while upland rainforest classes are restricted to what we term “interglacial refugia”.Estimated distributions and stable locations (consistently predicted in all four climate scenarios) for the various rainforest environment classes are our main, novel contribution. Each forest environment responds individualistically to climate change. Our results confirm the highly dynamic nature of the Wet Tropics landscape and present a much more detailed picture of landscape change since the late Pleistocene than previously has been available. This mapping exercise should be useful in the future for analyses of present-day biogeographic patterns. We argue that empirical modelling approaches have an important role in palaeoecology and global change research that is complementary to the developing mechanistic methods.     

Deeply divergent mitochondrial lineages reveal patterns of local endemism in chironomids of the Australian Wet Tropics

The Wet Tropics bioregion of north‐eastern Australia has been subject to extensive fluctuations in climate throughout the late Pliocene and Pleistocene. Cycles of rainforest contraction and expansion of dry sclerophyll forest associated with such climatic fluctuations are postulated to have played a major role in driving geographical endemism in terrestrial rainforest taxa. Consequences for the distributions of aquatic organisms, however, are poorly understood. The Australian non‐biting midge species Echinocladius martini Cranston (Diptera: Chironomidae), although restricted to cool, well‐forested freshwater streams, has been considered to be able to disperse among populations located in isolated rainforest pockets during periods of sclerophyllous forest expansion, potentially limiting the effect of climatic fluctuations on patterns of endemism. In this study, mitochondrial COI and 16S data were analysed for E. martini collected from eight sites spanning the Wet Tropics bioregion to assess the scale and extent of phylogeographic structure. Analyses of genetic structure showed several highly divergent cryptic lineages with restricted geographical distributions. Within one of the identified lineages, strong genetic structure implied that dispersal among proximate (<1 km apart) streams was extremely restricted. The results suggest that vicariant processes, most likely due to the systemic drying of the Australian continent during the Plio‐Pleistocene, might have fragmented historical E. martini populations and, hence, promoted divergence in allopatry.     

The influence of environment and life-history traits on the distribution of genes and individuals: a comparative study of 11 rainforest trees

This study investigates patterns of genetic connectivity among 11 co-distributed tropical rainforest tree species from the genus Elaeocarpus across a biogeographic barrier, the Black Mountain Corridor (BMC) in the Australian Wet Tropics (AWT). We analysed a combination of allelic and flanking region sequence data from microsatellite markers, and evaluated the relative influence of environmental preferences and functional traits on genetic diversity and gene flow. The results indicate that only in three species geographic structuring of haplotype distribution reflects a north vs. south of the BMC pattern. Environmental factors linked with altitude were recognized as affecting genetic trends, but the selective processes operating on upland species appear to be associated with competitiveness and regeneration opportunities on poor soil types rather than climate variables alone. In contrast to previous observations within southeastern Australian rainforests, genetic differentiation in the AWT appears to be associated with small-fruited rather than large-fruited species, highlighting how external factors can influence the dispersal dimension. Overall, this study emphasizes the importance of considering functional and environmental factors when attempting generalizations on landscape-level patterns of genetic variation. Understanding how plant functional groups respond to environmental and climatic heterogeneity can help us predict responses to future change.     

Comparative phylogeography and the history of endemic vertebrates in the Wet Tropics rainforests of Australia

We examine the effects of historical climate change on vertebrate differentiation in tropical rainforest by comparing phylogeographic patterns in six species of widespread rainforest-restricted herpetofauna from throughout the Wet Tropics of Australia. Qualitative and quantitative comparisons of phylogeographic structure reveal strikingly similar patterns of pre-Pleistocene vicariant population differentiation on either side of a previously identified biogeographic break (variously referred to as the Black Mountain Barrier or Corridor; BMC). While divergence across the BMC antedates the Pleistocene, the impact of Quaternary climate change is apparent in populations on either side of the BMC. Consistent with palaeoclimatological reconstructions for the region, the distribution and degree of mtDNA diversity suggests that populations were fragmented and reduced to multiple refugia during Pleistocene glacial periods, with expansion following Holocene rainforest recovery. This pattern is repeated on both sides of the BMC, but substantial differences in the amount and distribution of mtDNA diversity within species indicate the importance of species-specific ecological characteristics. The historical processes of extinction and (re)colonization revealed by the comparative phylogeographic analysis of mtDNA sequences substantiate earlier suggestions that current regional patterns of species distribution and diversity in the Wet Tropics are largely determined by local extinctions and subsequent recolonization driven by Quaternary climate changes.     

Effects of historical forest contraction on the phylogeographic structure of Australo‐Papuan populations of the red‐legged pademelon (Macropodidae: Thylogale stigmatica)

Geographic patterns of genetic variation are strongly influenced by historical changes in species habitats. Whether such patterns are common to co‐distributed taxa may depend on the extent to which species vary in ecology and vagility. We investigated whether broad‐scale phylogeographic patterns common to a number of small‐bodied vertebrate and invertebrate species in eastern Australian forests were reflected in the population genetic structure of an Australo‐Papuan forest marsupial, the red‐legged pademelon (Macropodidae: Thylogale stigmatica). Strong genetic structuring of mtDNA haplotypes indicated the persistence of T. stigmatica populations across eastern Australia and southern New Guinea in Pleistocene refugial areas consistent with those inferred from studies of smaller, poorly dispersing species. However, there was limited divergence of haplotypes across two known historical barriers in the northeastern Wet Tropics (Black Mountain Barrier) and coastal mideastern Queensland (Burdekin Gap) regions. Lack of divergence across these barriers may reflect post‐glacial recolonization of forests from a large, central refugium in the Wet Tropics. Additionally, genetic structure is not consistent with the present delimitation of subspecies T. s. wilcoxi and T. s. stigmatica across the Burdekin Gap. Instead, the genetic division occurs further to the south in mideastern Queensland. Thus, while larger‐bodied marsupials such as T. stigmatica did persist in Pleistocene refugia common to a number of other forest‐restricted species, species‐specific local extinction and recolonization events have resulted in cryptic patterns of genetic variation. Our study demonstrates the importance of understanding individualistic responses to historical climate change in order to adequately conserve genetic diversity and the evolutionary potential of species.     

Does biogeographical history matter? Diversity and distribution of lotic midges (Diptera: Chironomidae) in the Australian Wet Tropics

Abstract We examined broad scale patterns of diversity and distribution of lotic Chironomidae (Diptera) within the Wet Tropics bioregion of northern Queensland, Australia. Field surveys across broad latitudinal and altitudinal gradients within the Wet Tropics revealed a fauna of 87 species‐level taxa in 49 genera comprising three main elements: a small genuinely tropical fraction, and larger cosmopolitan and Gondwanan components. The latter group originated when Australia, as part of the ancient Gondwana supercontinent, was situated over Antarctic latitudes with a cooler, wetter climate than today. In the Wet Tropics, cool Gondwanan taxa occurred predominantly in upland and shaded lowland sites, but no species appeared narrowly temperature restricted, and there was no faunal zonation with altitude. Most chironomid species occurred at all latitudes within the Wet Tropics, with no evidence for an enduring effect of the historical rainforest contractions on current‐day distribution patterns. These findings contrast with those for aquatic faunas elsewhere in the world and for the terrestrial Wet Tropics fauna. We relate this to the generally broad environmental tolerances of Australian chironomids, and comment on why the latitudinal diversity gradient does not apply to the Australian chironomid fauna.     

The climatic drivers of long-term population changes in rainforest montane birds

Climate-driven biodiversity erosion is escalating at an alarming rate. The pressure imposed by climate change is exceptionally high in tropical ecosystems, where species adapted to narrow environmental ranges exhibit strong physiological constraints. Despite the observed detrimental effect of climate change on ecosystems at a global scale, our understanding of the extent to which multiple climatic drivers affect population dynamics is limited. Here, we disentangle the impact of different climatic stressors on 47 rainforest birds inhabiting the mountains of the Australian Wet Tropics using hierarchical population models. We estimate the effect of spatiotemporal changes in temperature, precipitation, heatwaves, droughts and cyclones on the population dynamics of rainforest birds between 2000 and 2016. We find a strong effect of warming and changes in rainfall patterns across the elevational-segregated bird communities, with lowland populations benefiting from increasing temperature and precipitation, while upland species show an inverse strong negative response to the same drivers. Additionally, we find a negative effect of heatwaves on lowland populations, a pattern associated with the observed distribution of these extreme events across elevations. In contrast, cyclones and droughts have a marginal effect on spatiotemporal changes in rainforest bird communities, suggesting a species-specific response unrelated to the elevational gradient. This study demonstrated the importance of unravelling the drivers of climate change impacts on population changes, providing significant insight into the mechanisms accelerating climate-induced biodiversity degradation.     

Congruent phylogeographical patterns of eight tree species in Atlantic Central Africa provide insights into the past dynamics of forest cover

Cycles of Quaternary climatic change are assumed to be major drivers of African rainforest dynamics and evolution. However, most hypotheses on past vegetation dynamics relied on palaeobotanical records, an approach lacking spatial resolution, and on current patterns of species diversity and endemism, an approach confounding history and environmental determinism. In this context, a comparative phylogeographical study of rainforest species represents a complementary approach because Pleistocene climatic fluctuations may have left interpretable signatures in the patterns of genetic diversity within species. Using 1274 plastid DNA sequences from eight tree species (Afrostyrax kamerunensis, A. lepidophyllus, Erythrophleum suaveolens, Greenwayodendron suaveolens, Milicia excelsa, Santiria trimera, Scorodophloeus zenkeri and Symphonia globulifera) sampled in 50 populations of Atlantic Central Africa (ACA), we averaged divergence across species to produce the first map of the region synthesizing genetic distinctiveness and standardized divergence within and among localities. Significant congruence in divergence was detected mostly among five of the eight species and was stronger in the northern ACA. This pattern is compatible with a scenario of past forest fragmentation and recolonization whereby forests from eastern Cameroon and northeastern Gabon would have been more affected by past climatic change than those of western Cameroon (where one or more refugia would have occurred). By contrast, southern ACA (Gabon) displayed low congruence among species that may reflect less drastic past forest fragmentation or a more complex history of vegetation changes. Finally, we also highlight the potential impact of current environmental barriers on spatial genetic structures.     

Immigrants and refugees: the importance of dispersal in mediating biotic attrition under climate change

Montane tropical rainforests are critically important areas for global bird diversity, but are projected to be highly vulnerable to contemporary climate change. Upslope shifts of lowland species may partially offset declines in upland species but also result in a process of lowland biotic attrition. This latter process is contingent on the absence of species adapted to novel warm climates, and isolation from pools of potential colonizers. In the Australian Wet Tropics, species distribution modelling has forecast critical declines in suitable environmental area for upland endemic birds, raising the question of the future role of both natural and assisted dispersal in species survival, but information is lacking for important neighbouring rainforest regions. Here we use expanded geographic coverage of data to model the realized distributions of 120 bird species found in north‐eastern Australian rainforest, including species from potential source locations in the north and recipient locations in the south. We reaffirm previous conclusions as to the high vulnerability of this fauna to global warming, and extend the list of species whose suitable environmental area is projected to decrease. However, we find that expansion of suitable area for some species currently restricted to northern rainforests has the potential to offset biotic attrition in lowland forest of the Australian Wet Tropics. By examining contrasting dispersal scenarios, we show that responses to climate change in this region may critically depend on dispersal limitation, as climate change shifts the suitable environmental envelopes of many species south into currently unsuitable habitats. For lowland and northern species, future change in vegetation connectivity across contemporary habitat barriers is likely to be an important mediator of climate change impacts. In contrast, upland species are projected to become increasingly isolated and restricted. Their survival is likely to be more dependent on the viability of assisted migration, and the emergence and persistence of suitable environments at recipient locations.     

Geographical genetic structuring and phenotypic variation in the Vellozia hirsuta (Velloziaceae) ochlospecies complex

? Premise of the study: Vellozia hirsuta forms a complex presenting wide morphological and anatomical variation, resulting in five specific names and 14 morpho-anatomical patterns occurring in disjunct populations. We carried out a phylogeographical study to investigate the existence of correlation among the genetic and morphological patterns within this complex, and to determine whether it is composed of various species or should be treated as an ochlospecies, a species having widely polymorphic and weakly polytypic complex variation, with morphological characteristics varying independently. ? Methods: We carried out phylogeographical analyses using cpDNA rpl32F-trnL intergenic region. ? Key results: We found 20 haplotypes in 23 populations sampled. The populations are genetically structured (Φ(ST) = 0.818) into four phylogeographical groups demonstrating geographical structuring but with no correlation with morpho-anatomical patterns. Our analyses do not support recognizing any of the species now synonymized under Vellozia hirsuta. The northern populations were the most genetically differentiated and could be considered a distinct taxon, as they are also morphologically different. ? Conclusions: It is recommended that Vellozia hirsuta be considered a single enormously variable species. The patterns of variation within V. hirsuta probably are related to climatic changes that occurred during the Pleistocene Epoch in tropical Brazil when reductions in forest cover favored the expansion of V. hirsuta populations into extensive lowland areas. The expansion of forest cover at the end of the glaciations would have again restricted the occurrence of campos rupestres vegetation to high elevations, which constitute the current centers of diversity of this species.     

The return of the frogs: The importance of habitat refugia in maintaining diversity during a disease outbreak

Recent decades have seen the emergence and spread of numerous infectious diseases, often with severe negative consequences for wildlife populations. Nevertheless, many populations survive the initial outbreaks, and even undergo recoveries. Unfortunately, the long‐term effects of these outbreaks on host population genetics are poorly understood; to increase this understanding, we examined the population genetics of two species of rainforest frogs (Litoria nannotis and Litoria serrata) that have largely recovered from a chytridiomycosis outbreak at two national parks in the Wet Tropics of northern Australia. At the wetter, northern park there was little evidence of decreased genetic diversity in either species, and all of the sampled sites had high minor allele frequencies (mean MAF = 0.230–0.235), high heterozygosity (0.318–0.325), and few monomorphic markers (1.4%–4.0%); however, some recovered L. nannotis populations had low N_e values (59.3–683.8) compared to populations that did not decline during the outbreak (1,537.4–1,756.5). At the drier, southern park, both species exhibited lower diversity (mean MAF = 0.084–0.180; heterozygosity = 0.126–0.257; monomorphic markers = 3.7%–43.5%; N_e = 18.4–676.1). The diversity patterns in this park matched habitat patterns, with both species having higher diversity levels and fewer closely related individuals at sites with higher quality habitat. These patterns were more pronounced for L. nannotis, which has lower dispersal rates than L. serrata. These results suggest that refugia with high quality habitat are important for retaining genetic diversity during disease outbreaks, and that gene flow following disease outbreaks is important for re‐establishing diversity in populations where it was reduced.     

Pan-European phylogeography of the aquatic snail Theodoxus fluviatilis (Gastropoda: Neritidae)

Investigating the geographical distribution of genetic lineages within species is critical to our understanding of how species evolve. As many species inhabit large and complex ranges, it is important that phylogeographical research take into account the entire range of widespread species to clarify how myriad extrinsic variables have affected their evolutionary history. Using phylogenetic, nested clade, and mismatch distribution analyses on a portion of the mitochondrial COI gene, I demonstrate that the wide-ranging freshwater snail Theodoxus fluviatilis possesses in parallel many of the phylogeographical patterns seen in less widespread freshwater species of Europe. Fragmentary forces play a major part in structuring the range of this species, with 12 of 14 geographically structured nested clades displaying a distribution consistent with fragmentation or restricted dispersal. Certain regions of southern Europe harbour the majority of genetic diversity (total haplotype diversity, H = 0.87), particularly Italy (H = 0.87) and areas surrounding the Black Sea (H = 0.81). Post-Pleistocene range expansion is pronounced, with the majority of northern European populations (95% of sample sites) having arisen from northern Italian individuals that initially colonized northern Germany. Additionally, two highly divergent haplotype lineages present in northern Germany imply that there were at least two postglacial recolonization routes. Estuaries may also provide a means of dispersal given that no genetic differentiation was found between estuarine populations and neighbouring freshwater populations. Taken together, these data reveal a species with a complex genetic history resulting from the fragmentary effects of European geology as well as continuous and discrete range expansion related to their aquatic biology.     

Phylogenomic approaches reveal how climate shapes patterns of genetic diversity in an African rain forest tree species

The world's second largest expanse of tropical rainforest is in Central Africa, and it harbours enormous species diversity. Population genetic studies have consistently revealed significant structure across Central African rainforest plants. In particular, previous studies have repeatedly demonstrated a north–south genetic discontinuity around the equatorial line, in a continuous expanse of rainforest where a climatic inversion is documented. Here, we took a phylogeographic approach by sequencing 351 nuclear markers in 112 individuals across the distribution of the African rainforest tree species Annickia affinis (Annonaceae). We showed for the first time that the north–south divide is the result of a single, major colonization event across the climatic inversion from an ancestral population located in Gabon. We suggested that differences in ecological niche of populations located on either side of this inversion may have contributed to this phylogenetic discontinuity. We found evidence for inland dispersal, predominantly in northern areas, and variable demographic histories among genetic clusters, indicating that populations responded differently to past climate change. We show how newly developed genomic tools can provide invaluable insights into our understanding of tropical rainforest evolutionary dynamics.     

A mitochondrial phylogeny of the rainforest skink genus Saproscincus, Wells and Wellington (1984)

The phylogenetic relationships and historical biogeography of 10 currently described rainforest skinks in the genus Saproscincus were investigated using mitochondrial protein-coding ND4 and ribosomal RNA 16S genes. A robust phylogeny is inferred using both maximum likelihood and Bayesian analysis, with all inter-specific nodes strongly supported when datasets are combined. The phylogeny supports the recognition of two major lineages (northern and southern), each of which comprises two divergent clades. Both northern and southern lineages have comparably divergent representatives in mid-east Queensland (MEQ), providing further molecular evidence for the importance of two major biogeographic breaks, the St. Lawrence gap and Burdekin gap separating MEQ from southern and northern counterparts respectively. Vicariance associated with the fragmentation and contraction of temperate rainforest during the mid-late Miocene epoch underpins the deep divergence between morphologically conservative lineages in at least three instances. In contrast, one species, Saproscincus oriarus, shows very low sequence divergence but distinct morphological and ecological differentiation from its allopatric sister clade within Saproscincus mustelinus. These results suggest that while vicariance has played a prominent role in diversification and historical biogeography of Saproscincus, divergent selection may also be important.     

Persistence in peripheral refugia promotes phenotypic divergence and speciation in a rainforest frog

It is well established from the fossil record and phylogeographic analyses that late Quaternary climate fluctuations led to substantial changes in species' distribution, but whether and how these fluctuations resulted in phenotypic divergence and speciation is less clear. This question can be addressed through detailed analysis of traits relevant to ecology and mating within and among intraspecific lineages that persisted in separate refugia. In a biogeographic system (the Australian Wet Tropics [AWT]) with a well-established history of refugial isolation during Pleistocene glacial periods, we tested whether climate-mediated changes in distribution drove genetic and phenotypic divergence in the rainforest frog Cophixalus ornatus. We combined paleomodeling and multilocus genetics to demonstrate long-term persistence within, and isolation among, one central and two peripheral refugia. In contrast to other AWT vertebrates, the three major lineages differ in ecologically relevant morphology and in mating call, reflecting divergent selection and/or genetic drift in the peripheral isolates. Divergence in mating call and contact zone analyses suggest that the lineages now represent distinct species. The results show that climate shifts can promote genetic and phenotypic divergence and, potentially, speciation and direct attention toward incorporating adaptive traits into phylogeographic studies to better resolve the mechanisms of speciation.     

The genetic pattern of population threat and loss: a case study of butterflies

Recent decreases in biodiversity in Europe are commonly thought to be due to land use and climate change. However, the genetic diversity of populations is also seen as one essential factor for their fitness. Genetic diversity in species across the continent of Europe has been recognized as being in part a consequence of ice age isolation in southern refugia and postglacial colonization northwards, and these phylogeographical patterns may themselves affect the adaptability of populations. Recent work on butterfly species with different refugia, colonization paths and genetic structures allows this idea to be examined. The 'chalk-hill blue' pattern is one of decreasing genetic diversity from south to north, whereas the 'woodland ringlet' pattern shows greater genetic diversity in eastern than in western lineages. Comparison of population demographic trends in species with these biogeographical patterns reveals higher rates of decrease with lower genetic diversity. This indicates reduced adaptability due to genetic impoverishment as a result of glacial and postglacial range changes. Analysis of phylogeographical pattern may be a useful guide to interpreting demographic trends and in conservation planning.     

Molecular phylogeography and conservation genetics of Sladenia celastrifolia inferred from chloroplast DNA sequence variation

The genetic variation and structure of Sladenia celastrifolia Kurz, a species of conservation concern, were investigated. Analyses of two chloroplast DNA loci (trnS-trnGand atpB-rbcL intergenic regions) were carried out for 24 populations of S. celastrifolia and five haplotypes were identified. High levels of genetic differentiation (G_ST = 1, F_ST = 1) were detected, which may be a result of limited gene flow caused by geographic isolation. Analysis of molecular variance suggests that the existence of marked phylogeographical structure within the haplotype distribution is probably due to geographic barriers among populations. The haplotype network and mismatch distribution analyses did not detect any signals for recent population expansions in S. celastrifolia. Thus, it can be inferred that the species likely persistedin situ during climatic oscillations. Considering its genetic diversity and uniqueness, conservation strategies are further discussed for this species.     

Recent speciation and limited phylogeographic structure in Mixophyes frogs from the Australian Wet Tropics

Through a combination of macroecological, paleoecological, and phylogeographical analyses, the rainforests of the Australian Wet Tropics (AWT) have emerged as a useful model for understanding sensitivity of species to past climatic change and, hence, for predicting vulnerability to future change. To extend the ecological breadth of comparative phylogeographic analyses, we investigate a clade of myobatrachid frogs, Mixophyes, a genus of large, stream-breeding but terrestrial frogs, three species of which are endemic to rainforests of the AWT. Here we (i) combine mtDNA, allozyme, and morphological data to refine knowledge of the geographic and environmental distribution of each taxon, (ii) resolve relationships among species, and (iii) use mtDNA phylogeography to infer responses of the three taxa to late-Pleistocene and Holocene climatic change. Each of the three species (Mixophyes carbinensis, Mixophyes coggeri, and Mixophyes schevilli) is effectively diagnosed by mtDNA, with the two small-bodied, allopatric species (M. carbinensis and M. schevilli) being sister-taxa. Mixophyes have a very different history from other AWT amphibians, with more recent speciation (net divergences <5%) and much lower and geographically unstructured mtDNA diversity within each species. The combination of low diversity (θ(Π)<0.36%) and strong signals of recent population expansion (Fu's Fs<0) suggests very high sensitivity to climate-driven rainforest dynamics, perhaps due to their large body size, low population density, and their requirement for both wet forest-floor litter and streams suitable for breeding. The results further emphasize the heterogeneity of species' responses to climate change and suggest that species dependent on multiple habitat types could be especially vulnerable.     

Conservation genetics of xerothermic beetles in Europe: the case of <Emphasis Type="Italic">Centricnemus leucogrammus</Emphasis>

Xerothermic habitats are closely related to continental steppes of Eurasia and contain communities rich in rare and endemic species, especially insects. Considering the dramatic loss of xerothermic habitats due to climatic and anthropogenic changes the evaluation of genetic variation and phylogeographical patterns in xerothermic species is a matter of utmost importance if appropriate conservation measures are to be undertaken. In this paper 3 mitochondrial genes and 3 nuclear markers were used for evaluation of genetic diversity of populations of the weevil Centricnemus leucogrammus from central-east Europe. These data were used for the recognition of conservation units as well as centers of genetic diversity which could be considered as present “warm-stage” refugia for xerothermic beetle assemblages. The most diverse are eastern and central populations from Ukraine and central Poland, however, also isolated groups of populations from the Pannonian Basin and northern Poland possessed a unique genetic signature. This lead to the conclusion that all three regional groups of populations are significantly isolated from each other and represent distinct evolutionary lineages so they should be considered as separate Management Units and Evolutionary Significant Units. C. leucogrammus can be regarded as an excellent representative for typically xerothermophilous, flightless beetles and knowledge about its genetic diversity may be used for the conservation and management of entire xerothermic communities, especially for those with low mobility invertebrate taxa. Further research on the genetic diversity of various organisms with varying levels of mobility should be undertaken to broaden our knowledge on the conservations needs of xerothermic assemblages.