Distribution patterns of dragonflies (Odonata) in Central Asia

The dragonfly fauna of Central Asia reveals distinct vertical differentiation. Three groups of species can be distinguished: mountain (24 species), plain (18), and plain-mountain (34) ones. The ranges observed can be classified into 7 principal types: plain, mountain, continuous boreo-montane, disjunctive Central Asian boreomontane, disjunctive Tien Shan boreo-montane, Central Asian, and Pamir-Alay plain-mountain. The leading factors determining the distribution of dragonflies are the temperature and the presence of streams suitable for preimaginal development; the former factor determines the potential ranges, and the latter, the actual ones. The present-day composition, structure, and vertical distribution of the dragonfly fauna formed during the historical time, after the development of artificial irrigation canals which provided new habitats for dragonflies.     

Impacts of climate change on dragonflies and damselflies in West and Central Asia

Aim

To project the impact of climate change on dragonfly and damselfly diversity in West and Central Asia.

Location

West and Central Asia.

Time period

1900–2020 data used to predict distributions in 2070 and 2100.

Taxon studied

Odonata.

Methods

Based on 149,001 records, distribution models were created for 159 species using MaxEnt. Environmental variables consisted of climate variables taken from BIOCLIM, river data and soil data. The future climate data were obtained from CHELSA from CMIP6 climate models. The same variables were collected for three scenarios (SSP1-2.6, SSP3-7.0 and SSP5-8.5) of shared socioeconomic pathways for the years 2050–2070 and 2080–2100. For each scenario and period, diversity maps were prepared for six species groups: all species, Lentic, Lotic, Oriental, Afrotropical and Palaearctic species.

Results

Strong declines in diversity are expected in western Turkey, the Levant and Azerbaijan, and to a lesser extent in parts of Iran and southern Central Asia. An increase is expected in eastern Turkey and at higher elevations in Central Asia with a limited increase throughout the Arabian Peninsula. In contrast to expectations, a decrease in areas with <15 species was found. Faunal composition is predicted to show strong shifts, with Palaearctic species declining and Oriental and Afrotropical species increasing. No clear difference between the trend of lentic and lotic species is found, although there are clear spatial differences in trend between these groups.

Main Conclusions

Climate change will result in strong changes in diversity and distribution of dragonflies and damselflies in West and Central Asia with regional declines and increases. None of the species are predicted to go extinct based on the impact of climate change only, however, the combined impact of climate change and anthropogenic forces is likely to push some of the species to near extinction by 2100.     

Molecular phylogeny of Coriaria, with special emphasis on the disjunct distribution

Coriaria, which has the most conspicuously disjunct distribution of the flowering plants, is distributed in four separate areas of the world. The phylogenetic relationships of 12 Coriaria species collected from the representative disjunct areas were inferred by comparing 2416 bp of the combined data set of rbcL (a large subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase) and matK (maturase K) genes. The phylogenetic tree shows that the Chile-Papua New Guinea-New Zealand-Pacific islands species and the Central America-northern South America species form a sister group, and the Eurasian clade is more basal to them. The divergence time between the Eurasian group and the other species was estimated as 63 or 59 million years ago using rbcL and matK molecular clocks, respectively. These results do not support previously proposed hypotheses which explain the disjunct distribution on the basis of continental drift but suggest that the distribution pattern was formed by several geographical migrations and separations in the Cenozoic.     

Climate hindcasts: exploring the disjunct distribution of Diopatra biscayensis

The ecosystem engineer onuphid polychaete Diopatra biscayensis has a continuous population in the Bay of Biscay from the Cantabria coast in Spain to southern Brittany in France. A group of disjunct populations also are found in the English Channel, separated from the Biscay population by more than 400 coastal kilometers. It remains unclear whether D. biscayensis is native to the Bay of Biscay; it is also debated whether the disjunct populations in the English Channel are relics of a formerly continuous population, or the product of recent introductions through aquaculture. Here, we use climate hindcasts to explore hypotheses about the D. biscayensis historical distribution in Europe. If D. biscayensis is native, its range would have been restricted to southern Iberia and the Mediterranean during the Last Glacial Maximum (21,000 BP). However, the species is completely absent from both regions today, further supporting its interpretation as a non‐native species. If it was historically present in Europe, the climate hindcasts are congruent with range contraction in the Last Glacial Maximum (21,000 BP), expansion in the Mid‐Holocene Warm Period (6000 BP), and contraction again in the past 1000 years (850–1850), prior to the first reports of D. biscayensis on the Spanish and French Atlantic coasts. However, the simulations do not support there being climatic refugia along the English Channel coast that would account for the existence of relic populations. Taken together, the evidence suggests that D. biscayensis has been introduced to the Bay of Biscay, and that disjunct populations in the English Channel are the result of recent transport through human activities, perhaps aquaculture.     

Mapping the disjunct distribution of introduced codling moth Cydia pomonella in China

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Phylogeographic distribution of mitochondrial DNA macrohaplogroup M in India

Indian subcontinent harbours both the human mtDNA macrohaplogroups M and N, of which M is the most prevalent. In this study, we discuss the overall distribution of the various haplogroups and sub-haplogroups of M among the different castes and tribes to understand their diverse pattern with respect to geographical location and linguistic affiliation of the populations. An overview of about 170 studied populations, belonging to four distinct linguistic families and inhabiting different geographic zones, revealed wide diversity of about 22 major haplogroups of M. The tribal populations belonging to the same linguistic family but inhabiting different geographical regions (Dravidian and Austro-Asiatic speakers) exhibited differences in their haplogroup diversity. The northern and southern region castes showed greater diversity than the castes of other regions.     

The thermohaline circulation and the control of ice ages

It is found that the global salinity variations associated with the thermohaline circulation may have a tendency to make the circulation increasingly asymmetric with respect to the equator. As a consequence the salinity difference between the Pacific and the Atlantic Ocean may be slowly increasing. Such a process could have a time scale long enough to be comparable with the time span between major glaciations. A speculative glaciation cycle is proposed which involves the above mentioned property of the thermohaline circulation. In this cycle the role of a Northern Hemisphere glaciation is to bring excess freshwater from the Pacific to the Atlantic.     

The adaptedness of the floral phenotype in a relict endemic, hawkmoth-pollinated violet. 2. Patterns of variation among disjunct populations

This study examines patterns of variation in quantitative floral traits among 18 disjunct populations of Viola cazorlensis (Violaceae), a relict endemic violet of south-eastern Spain. At all sites, the species is almost exclusively pollinated by a single species of day-flying hawkmoth. Differences between populations were significant for all traits examined, and population means exhibit a broad range of variation. When all characters are considered together, each population displays a unique combination of characters. Despite interpopulation differences in character means, local populations retain most of the variability of the entire species. Floral traits do not vary in unison among flowers, and at least four different subsets of independently varying traits are identifiable. Floral similarity between populations of V. cazorlensis was largely unrelated to geographic proximity, as revealed by analyses at both large and small geographic scales. The geographic pattern of floral variation among populations represents a random patchwork, with unique combinations of character means occurring randomly across the study region. Marked population differences in quantitative floral traits in spite of spatial constancy in the identity of pollinators, a disintegrated floral phenotype, and prevailingly random geographic variation among populations, suggest low adaptedness of the floral phenotype of V. cazorlensis to its current hawkmoth pollinators.     

Phylogeographic incongruence of codistributed amphibian species based on small differences in geographic distribution

Codistributed species may display either congruent phylogeographic patterns, indicating similar responses to a series of shared climatic and geologic events, or discordant patterns, indicating independent responses. This study compares the phylogeographic patterns of two similarly distributed salamander species within the Pacific Northwest of the United States: Cope's giant salamander (Dicamptodon copei) and Van Dyke's salamander (Plethodon vandykei). Previous studies of P. vandykei support two reciprocally monophyletic lineages corresponding to coastal populations, located from the Olympic Mountains to the mouth of the Columbia River, and inland populations within the Cascade Mountains. We hypothesized that D. copei would have a congruent phylogeographic pattern to P. vandykei due to similarity in distribution and dependence upon similar stream and stream-side habitats. We test this hypothesis by estimating the phylogeny of D. copei using approximately 1800bp of mitochondrial DNA and comparing it to that of P. vandykei. Sympatric populations of D. copei and of P. vandykei display an identical phylogeographic pattern, suggesting similar responses within their shared distribution. Populations of D. copei occurring outside the range of P. vandykei displayed high levels of genetic divergence from those sympatric to P. vandykei. Overall, phylogeographic patterns between the two species were ultimately incongruent due to the high divergence of these allopatric populations. These results provide an example of codistributed species displaying overall incongruent phylogeographic patterns while simultaneously displaying congruent patterns within portions of their shared geographic distribution. This pattern demonstrates that a simple dichotomy of congruent and incongruent phylogeographic patterns of codistributed species may be too simplistic and that more complex intermediate patterns can result even from minor differences in species' ranges.     

Theoretical analysis of the ice crystal size distribution in frozen aqueous specimens.

To estimate theoretically how suited different freezing techniques are for freezing of freeze-etch specimens, it is necessary to know the relationship between specimen cooling rate and the resulting average ice crystal size. Using a somewhat simplified theoretical analysis, we have derived the approximate ice crystal size distribution of nonvitrified frozen aqueous specimens frozen at different cooling rates. The derived size distribution was used to calculate the relationship between relative change in average ice crystal size, (delta l/l), and relative change in specimen cooling rate delta (dT/dt)/(dT/dt). We found this relationship to be (delta l/l) = -k X delta (dT/dt)/(dT/dt) where k = 1.0 when specimen solidification takes place at about -6 degrees C, and k congruent to 1.3 when it takes place at about -40 degrees C.     

The influence of life history and diet on the distribution of catarrhine primates during the Pleistocene in eastern Asia

Environmental changes during the Pleistocene in eastern Asia had profound impacts on the distributions of mammalian groups. Critical for many mammals were the southward latitudinal shifts of the tropical and subtropical vegetational zones, and decreases in the areas of these zones. Examination of the responses of members of a single clade, the Catarrhini, indicates that the main catarrhine genera of eastern Asia responded individually to the environmental changes in the Pleistocene. These responses were influenced by the life history parameters and diets of the genera involved. Those animals (macaques, langurs) with shorter gestation times, shorter weaning periods, shorter interbirth intervals, higher intrinsic rates of increase of population, and abilities to survive on a wider variety of vegetation in seasonal habitats were less adversely affected than those (gibbons, orangutans and the giant extinct hominoid, Gigantopithecus) with more protracted reproductive schedules, lower intrinsic rates of population increase and preferences for the higher quality foods (especially ripe fruits) of less seasonal environments. Hominids, while displaying "hyper-ape" life history parameters, increasingly overcame the constraints of these parameters through extrasomatic means not available to other catarrhines. This ability made possible their colonization, by the Late Pleistocene, of highly seasonal habitats such as tundra, which were off-limits to non-culture-bearing catarrhines.     

Phylogeographic analysis of mitochondrial DNA in northern Asian populations

To elucidate the human colonization process of northern Asia and human dispersals to the Americas, a diverse subset of 71 mitochondrial DNA (mtDNA) lineages was chosen for complete genome sequencing from the collection of 1,432 control-region sequences sampled from 18 autochthonous populations of northern, central, eastern, and southwestern Asia. On the basis of complete mtDNA sequencing, we have revised the classification of haplogroups A, D2, G1, M7, and I; identified six new subhaplogroups (I4, N1e, G1c, M7d, M7e, and J1b2a); and fully characterized haplogroups N1a and G1b, which were previously described only by the first hypervariable segment (HVS1) sequencing and coding-region restriction-fragment-length polymorphism analysis. Our findings indicate that the southern Siberian mtDNA pool harbors several lineages associated with the Late Upper Paleolithic and/or early Neolithic dispersals from both eastern Asia and southwestern Asia/southern Caucasus. Moreover, the phylogeography of the D2 lineages suggests that southern Siberia is likely to be a geographical source for the last postglacial maximum spread of this subhaplogroup to northern Siberia and that the expansion of the D2b branch occurred in Beringia ~7,000 years ago. In general, a detailed analysis of mtDNA gene pools of northern Asians provides the additional evidence to rule out the existence of a northern Asian route for the initial human colonization of Asia.     

The distribution of Australian relict plants and its bearing on angiosperm evolution

The distribution of relict plants in the Australian flora shows a bimodal distribution of genera with relict vegetative characters and a unimodal distribution centred on N.E. Queensland for floral characters. Archaic features of the vegetative group link them with the Glossopteridae of Permian age. The geophysical history of the continent is reviewed and indicates only minor climatic changes since the Permian, which would permit the survival of primitive vegetative features. The bimodal distribution of this group is accounted for by the Cretaceous marine invasion of the continent and the unimodal distribution of the floral relicts by a preponderance of genera of Indo-Malaysian affinity, which could not have entered Australia until contact was made with New Guinea about 45 m. y. B.P. Two different cycles of evolutionary diversification are responsible for the two elements. Vegetative features of the Proteaceae relate to the Glossopteridae and are supported by Permian fossils scarcely distinguishable from modern leaves of Epacridaceae. If recent discoveries of Glossopteris fructifications are accepted as pro-angiosperms, it is shown that some anomalies in the vascular supply to the androecium in the Proteaceae can be accounted for.     

Molecular divergence in the eastern Asia– eastern North America disjunct section Rytidospermum of Magnolia (Magnoliaceae)

Molecular divergence in the eastern Asia—eastern North American disjunct section Rytidospermum of Magnolia was investigated by allozyme electrophoresis, chloroplast DNA (cpDNA) restriction site analysis, and gene sequencing. We calculated Nei's genetic identities between two Asian species, M. officinalis var. biloba and M. hypoleuca, and three American species, M. tripetala, M. fraseri var. fraseri, and M. macrophylla var. macrophylla, by using gene frequency data from 17 nuclear-encoded allozyme loci in 67 populations. We then estimated cpDNA sequence divergence between the five species by examining restriction site variation for ten endonucleases over the entire genome. Finally, nucleotide sequences of the chloroplast gene rbcL were compared between M. hypoleuca, M. tripetala, and M. macrophylla var. macrophylla. All three methods consistently yielded low divergence values between the American species M. tripetala and its Asian sister taxa, M. officinalis var. biloba and M. hypoleuca (Nei's I = 0.712 and 0.809, respectively; D-cpDNA = 0.083% for both pairs; D-rbcL = 0.000% between M. tripetala and M. hypoleuca). The other two American species, M. fraseri var. fraseri and M. macrophylla var. macrophylla, neither of which is sister to the Asian taxa, exhibited much higher divergence from the Asian taxa. We interpreted the low divergence between M. tripetala and its Asian sister taxa as a result of recent separation (the late Miocene to early Pliocene), based on time estimates from molecular data as well as geological and paleoclimatic evidence. A comparison of our results with those of the earlier studies revealed a diverse array of levels of divergence between several eastern Asian and eastern North American species pairs. Though different extinction patterns and variation in molecular evolutionary rates may be partly responsible, this heterogeneous pattern of divergence is best explained by different times of disjunction in different taxa, which in turn suggests that the floristic similarity between the two continents was most likely attained by multiple migrations via both Bering and North Atlantic land bridges, or possibly even with involvement of dispersal.