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1.
Phytogeography of Genu and Homag,two mountains with an Irano–Turanian flora in the Saharo–Sindian regional zone,south Iran
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The Saharo–Sindian regional zone encompasses the flat and arid areas of North Africa, the Arabian Peninsula, southern Iran and the deserts of Pakistan and west India. There are some scattered mountains situated within this area, like Hoggar in Sahara, Saint Catherine in Sinai and Genu and Homag in southern Iran. These highlands serve as interglacial refugia for cold adapted plant species. In the present study, phytogeographical patterns and relationships of the flora of Genu and Homag mountains are described and discussed in relation to the phytogeography of the flora of low‐lying Hormoz Island. According to a chorological assesment of the flora, Genu and Homag mountains belong to the Irano–Turanian region with 59% of the species restricted to this area. In contrast, the surrounding lowland plains are part of the Saharo–Sindian area with a rather high proportion of widespread species (17%) and Somalia–Masai‐linking elements (20%). It is noteworthy that several Turanian enclaves also occur in the lowland zone. Furthermore, the distributional patterns imply that the mountainous Irano–Turkestanian region is an integrated area which is supposedly distinct from the Turanian lowland areas in the north and from the Saharo–Sindian lowland areas in the south. On the other hand, the expansive floras of Turanian and Saharo–Sindian regions are linked to each other. Endemic species in lowland areas in south Iran are mostly either frost sensitive vicariants of cold adapted Turanian species or of Saharo–Sindian origin, while the highland endemics in the area trace their origins to the Irano–Turkestanian region. 相似文献
2.
Cutting the Gordian Knot: Phylogenetic and ecological diversification of the Mesalina brevirostris species complex (Squamata,Lacertidae)
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Jiří Šmíd Jiří Moravec Václav Gvoždík Jan Štundl Daniel Frynta Petros Lymberakis Paschalia Kapli Thomas Wilms Andreas Schmitz Mohammed Shobrak Saeed Hosseinian Yousefkhani Eskandar Rastegar‐Pouyani Aurora M. Castilla Johannes Els Werner Mayer 《Zoologica scripta》2017,46(6):649-664
Mesalina are small lacertid lizards occurring in the Saharo‐Sindian deserts from North Africa to the east of the Iranian plateau. Earlier phylogenetic studies indicated that there are several species complexes within the genus and that thorough taxonomic revisions are needed. In this study, we aim at resolving the phylogeny and taxonomy of the M. brevirostris species complex distributed from the Middle East to the Arabian/Persian Gulf region and Pakistan. We sequenced three mitochondrial and three nuclear gene fragments, and in combination with species delimitation and species‐tree estimation, we infer a time‐calibrated phylogeny of the complex. The results of the genetic analyses support the presence of four clearly delimited species in the complex that diverged approximately between the middle Pliocene and the Pliocene/Pleistocene boundary. Species distribution models of the four species show that the areas of suitable habitat are geographically well delineated and nearly allopatric, and that most of the species have rather divergent environmental niches. Morphological characters also confirm the differences between the species, although sometimes minute. As a result of all these lines of evidence, we revise the taxonomy of the Mesalina brevirostris species complex. We designate a lectotype for Mesalina brevirostris Blanford, 1874; resurrect the available name Eremias bernoullii Schenkel, 1901 from the synonymy of M. brevirostris; elevate M. brevirostris microlepis (Angel, 1936) to species status; and describe Mesalina saudiarabica, a new species from Saudi Arabia. 相似文献
3.
Hsiang‐Hsi Hong Tzung‐Hai Yen Adrienne Hong Ting‐An Chou 《Journal of cellular and molecular medicine》2015,19(6):1208-1217
Designed sockets prepared on the mandibles of nine Beagle dogs were divided into three groups: Calcitriol +Alloplast, Alloplast and Empty. Five of the nine dogs received Vit.D3 and calcium supplement (Vit.D/Ca group), while the other four dogs without supplements were assigned to Non‐Vit.D/Ca group. After 4 weeks, the extent of vertical ridge resorption (VRR), bone density (density), new bone formation (NBF) and implant stability quotient (ISQ) were measured. Following systemic Vit.D/Ca administration, the Empty subgroup showed significant differences from the Calcitriol + Alloplast subgroup on variants NBF/Density/VRR and the Alloplast subgroup on items NBF/Density/ISQ/VRR. Alternatively, the Calcitriol + Alloplast subgroup revealed higher values of NBF/Density/ISQ (P < 0.001) and a lower VRR value (P = 0.001) than the Alloplast subgroup. Although there were no significant differences in NBF (P = 0.349), density (P = 0.796), ISQ (P = 0.577) and VRR (0.979) comparisons on alloplast treatment between the Vit.D/Ca and Non‐Vit.D/Ca groups, local application with Calcitriol + Alloplast demonstrated better NBF/Density/ISQ (P = 0.02 to <0.001) effects than which of Alloplast subgroups. Consequently, the results showed that both systemic and local vitamin D3 treatment might accelerate bone regeneration in dogs. Within the using dose, systemic vitamin D3 treatment displayed a superior stimulating effect than local vitamin D3 application did. 相似文献
4.
Matthew Iacchei Tal Ben‐Horin Kimberly A. Selkoe Christopher E. Bird Francisco J. García‐Rodríguez Robert J. Toonen 《Molecular ecology》2013,22(13):3476-3494
We combine kinship estimates with traditional F‐statistics to explain contemporary drivers of population genetic differentiation despite high gene flow. We investigate range‐wide population genetic structure of the California spiny (or red rock) lobster (Panulirus interruptus) and find slight, but significant global population differentiation in mtDNA (ΦST = 0.006, P = 0.001; Dest_Chao = 0.025) and seven nuclear microsatellites (FST = 0.004, P < 0.001; Dest_Chao = 0.03), despite the species’ 240‐ to 330‐day pelagic larval duration. Significant population structure does not correlate with distance between sampling locations, and pairwise FST between adjacent sites often exceeds that among geographically distant locations. This result would typically be interpreted as unexplainable, chaotic genetic patchiness. However, kinship levels differ significantly among sites (pseudo‐F16,988 = 1.39, P = 0.001), and ten of 17 sample sites have significantly greater numbers of kin than expected by chance (P < 0.05). Moreover, a higher proportion of kin within sites strongly correlates with greater genetic differentiation among sites (Dest_Chao, R2 = 0.66, P < 0.005). Sites with elevated mean kinship were geographically proximate to regions of high upwelling intensity (R2 = 0.41, P = 0.0009). These results indicate that P. interruptus does not maintain a single homogenous population, despite extreme dispersal potential. Instead, these lobsters appear to either have substantial localized recruitment or maintain planktonic larval cohesiveness whereby siblings more likely settle together than disperse across sites. More broadly, our results contribute to a growing number of studies showing that low FST and high family structure across populations can coexist, illuminating the foundations of cryptic genetic patterns and the nature of marine dispersal. 相似文献
5.
Björn‐Axel Beier 《分类学与生物多样性》2013,11(3):221-263
The taxonomy of the desert shrub genus Fagonia is revised in detail. In total 167 names are accounted for, lectotypes are selected for 33 names, and two names are neotypified. A key to the 34 species is presented, as well as distribution maps for each species. Three new species are described and illustrated, F. densispina and F. latistipulata from Somalia, and F. hadramautica from Yemen. Of the accepted species, 24 are restricted to the Old World and eight to the New World. Most of the Old World species are confined to the Saharo‐Sindian region, with two extending to parts of Macaronesia. Eight species are endemic to the Somali‐Masai region, and two are restricted to southern Africa. In the New World four species are endemic to Baja California, two to northern Baja California and adjacent parts of southwestern USA, one to the province of Coahuila in northeastern Mexico, and one to Chile and Peru. The names of all four species of Fagonia currently on the IUCN Red List of Threatened Plants are put into synonymy. 相似文献
6.
Z. Chen H. Nie C. E. Grover Y. Wang P. Li M. Wang H. Pei Y. Zhao S. Li J. F. Wendel J. Hua 《Plant biology (Stuttgart, Germany)》2017,19(3):484-493
- Cotton (Gossypium spp.) is commonly grouped into eight diploid genomic groups, designated A–G and K, and an allotetraploid genomic group, AD. Gossypium raimondii (D5) and G. arboreum (A2) are the putative contributors to the progenitor of G. hirsutum (AD1), the economically important fibre‐producing cotton species.
- Mitochondrial DNA from week‐old etiolated seedlings was extracted from isolated organelles using discontinuous sucrose density gradient method. Mitochondrial genomes were sequenced, assembled, annotated and analysed in orderly.
- Gossypium raimondii (D5) and G. arboreum (A2) mitochondrial genomes were provided in this study. The mitochondrial genomes of two diploid species harboured circular genome of 643,914 bp (D5) and 687,482 bp (A2), respectively. They differ in size and number of repeat sequences, both contain illuminating triplicate sequences with 7317 and 10,246 bp, respectively, demonstrating dynamic difference and rearranged genome organisations. Comparing the D5 and A2 mitogenomes with mitogenomes of tetraploid Gossypium species (AD1, G. hirsutum; AD2, G. barbadense), a shared 11 kbp fragment loss was detected in allotetraploid species, three regions shared by G. arboreum (A2), G. hirsutum (AD1) and G. barbadense (AD2), while eight regions were specific to G. raimondii (D5). The presence/absence variations and gene‐based phylogeny supported that A‐genome is a cytoplasmic donor to the progenitor of allotetraploid species G. hirsutum and G. barbadense.
- The results present structure variations and phylogeny of Gossypium mitochondrial genome evolution.
7.
Microsatellite DNA markers indicate three genetic lineages in East Asian indigenous goat populations
K. Nomura K. Ishii H. Dadi Y. Takahashi M. Minezawa C. Y. Cho Sutopo M. O. Faruque D. Nyamsamba T. Amano 《Animal genetics》2012,43(6):760-767
The genetic differentiation and phylogenetic relationships of 18 indigenous goat populations from seven East Asian countries were analysed based on data obtained from 26 microsatellite DNA markers. The mean number of alleles (MNA) per population ranged from 2.5 to 7.6, with an average of 5.8. Genetic variability estimated from MNA and heterozygosity (HE and HO) were relatively low in coastal and island populations. A heterozygous deficiency within populations (FIS = 0.054, P < 0.001) and total inbreeding (FIT = 0.181, P < 0.01) were observed, and genetic differentiation in the populations (FST) was 13.4%. The results of Bayesian model‐based clustering and a neighbour‐joining tree based on Nei's genetic distance showed that Asian goat populations could be subdivided into at least the following three genetic clusters: East Asian, Southeast Asian and Mongolian. These results are in close accordance with conventional morphological and geographical classifications and migration history. 相似文献
8.
Michel Sezonlin Rose Ndemah Georg Goergen Bruno Le Rü Stéphane Dupas Jean‐François Silvain 《Entomologia Experimentalis et Applicata》2012,145(2):143-152
The cereal stem borer Busseola fusca Fuller (Lepidoptera: Noctuidae) is a species endemic to sub‐Saharan Africa. It is a major pest of maize and cultivated sorghum, the main cereal crops on the African mainland. Previous studies using mitochondrial markers revealed the presence of three clades of haplotypes (W, KI, KII) among B. fusca populations. Previous preliminary studies based on a few B. fusca individuals collected from three localities within the Guineo‐Congolian rain forest in Cameroon demonstrated a matching with clade KII, a fairly surprising result because the putative centre of origin of that clade is located 3 000 km away in East Africa. To check this finding, 120 individuals of B. fusca covering several Cameroonian sites belonging to both Guineo‐Congolian rain forest and Afromontane vegetation mosaics were collected. Comparison of cytochrome b sequences using the same marker revealed low mitochondrial diversity (h = 0.483 ± 0.054, π = 0.073 ± 0.061%). Moreover, molecular diversity in the Guineo‐Congolian rain forest zone was lower than that in Afromontane vegetation, which is therefore thought to be the likely starting point for the colonization of other zones in Cameroon. The study showed a moderate but significant structuring between populations (ΦST = 0.034, P<0.001) as well as within and among the two Cameroonian phytogeographical groups considered (ΦSC = 0.000 and ΦCT = 0.051, respectively, both P<0.001). Nested clade phylogeographic analysis indicated that all Cameroonian clades with significant geographical associations were interpreted as a phenomenon of contiguous range expansion. All results suggest that the Cameroonian population of B. fusca is relatively recent and originates from the recent geographical expansion of clade KII. 相似文献
9.
Sebastian Pfautsch Craig Macfarlane Nicholas Ebdon Roger Meder 《Trees - Structure and Function》2012,26(3):963-974
Accurate measurement of sapwood depth (D
S) is essential for calculating volumetric water use of individual trees and stands. Various methods are available to measure
D
S but their accuracy is rarely cross-validated. We sampled 15 Eucalyptus and 1 Corymbia species along a gradient of aridity and obtained reference values of D
S in fresh wood cores using light microscopy, which represents our reference method. We compared this method to the simpler
and widely used macroscopic method: visual assessment of natural or induced colour change from sapwood to heartwood. In a
third method, estimation of D
S was based on species-specific models that rely on wood properties measured using near infrared spectroscopy (NIR). Microscopy
allowed clear identification of D
S based on the presence of blocked vessels. Measurement of D
S using microscopic methods was possible for 78 of a total of 80 cores and ranged from 3.6 mm (E. loxophleba) to 43.8 mm (E. viminalis). Macroscopic assessment clearly differentiated sapwood and heartwood in 60 cores. Results from microscopic and macroscopic
methods agreed closely (<10% deviation between estimates) in 35 of 78 cores. After elimination of clearly erroneous measurements
(>50% deviation between estimates), macroscopic measurement across all species agreed well with microscopic assessment of
D
S (R
2 = 0.92). Models developed for differentiation between sapwood and heartwood using NIR spectroscopy were very robust (high
coefficient of determination) for four species, but D
S could only be predicted well for one (E. obliqua) of the four species. Even after elimination of apparent false estimates, prediction of D
S by NIR across species was not as strong as for macroscopic assessment (R
2 = 0.88). D
S can accurately be measured using microscopy if vessel occlusion is clearly visible. Although slightly overestimated, D
S from macroscopic assessment was generally similar to that measured by microscopy. NIR spectroscopy was unable to predict
D
S with acceptable accuracy for the majority of species. Further improvements in the prediction of D
S using NIR will require more intensive model calibration and validation, and may not be applicable to all species. 相似文献
10.
M. Wang G. Lang A. Schreiber 《Journal of Zoological Systematics and Evolutionary Research》2002,40(4):232-236
DNA‐microsatellite polymorphism (four loci) was studied in 56 male roe deer (Capreolus capreolus) from a 900‐ha hunting territory in the Vosges du Nord Mountains (France), culled over 34 years (1956–1990). Changed allele frequencies at two loci within this period, and increased allelic diversity, were traced to a phase of reduced population density and subsequent immigration. Decadic population samples collected within 900‐ha were distinguished by higher genetic variability measures than were certain geographical samples across Central Europe (4–900 km). On average, the decadic cohorts were distinguished by a gene diversity index of GST = 0.0286, and a genetic distance of D = 0.0938, which reflect 54% (GST) and 69% (D) of the respective geographic (350 km) differentiation indices of roe deer in Central Europe. The importance of demography and population ecology effects for microevolution in a large mammal is demonstrated, as is the risk of artefact by composing population samples of deer over several years. Population genetic screening should cover various demes of roe deer from the same general region, and be based on many unlinked polymorphic loci, to minimize the distorting effects of genetic dynamics at the small spatial scale. 相似文献
11.
The present study deals with the analysis of the floristic composition and plant diversity of Wadi Gimal protectorate. Its major aim is to identify community types and environmental factors that affect their growth and distribution. These quantitative data provide rangers with knowledge that is necessary for monitoring and managing plant communities within the protected areas, as well as restoration of vegetation‐depleted habitats. Twenty‐seven stands were selected along the length of Wadi and its tributaries. Thirty‐five species were recorded in Wadi Gimal; with Poaceae as the dominant family and Phanerophytes dominating over other life forms. Saharo‐Arabians were the predominant chorological element. Six vegetation groups were recognized in Wadi Gimal. Zilla spinosa (VG C) which inhabited the Wadi bed had the highest species richness, species turnover, relative evenness and relative concentration of dominance. Capparis sinaica (VG A) which inhabited the mountain slope had the lowest species richness, relative evenness and relative concentration of dominance, while Salvadora persica group had the lowest species turnover. Phoenix dactylifera–Hyphaene thebaica (VG F) which dominated the deltaic part of Wadi, had the highest salinity; whilst Acacia ehrenbergiana (VG E) which dominated the upper‐stream part of the Wadi had the lowest value of salinity. 相似文献
12.
Effect of the Aegean Sea barrier between Europe and Asia on differentiation in Juniperus drupacea (Cupressaceae)
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Karolina Sobierajska Krystyna Boratyńska Anna Jasińska Monika Dering Tolga Ok Bouchra Douaihy Magda Bou Dagher‐Kharrat Ángel Romo Adam Boratyński 《Botanical journal of the Linnean Society. Linnean Society of London》2016,180(3):365-385
Juniperus drupacea is an eastern Mediterranean mountain tree with a disjunct geographical range. We hypothesized that this disjunct occurrence (the Peloponnese in Europe and the Taurus and Lebanon Mountains in Asia) should be reflected in the patterns of genetic and morphological diversity and differentiation. Nuclear microsatellite markers (nSSR) and biometric variables of the cones and seeds were examined on material sampled from four populations in Europe and eight in Asia. The Asian populations were characterized by a higher level of genetic diversity than the European populations. The genetic differentiation among populations was moderate but significant (FST = 0.101, P < 0.001). According to the clustering performed with BAPS, six genetically and geographically groups of populations were found: I and II from the Peloponnese; III from the Taurus Mountains; IV and V from the Anti‐Taurus Mountains; and VI from the Lebanon Mountains. The level of genetic differentiation among these six groups (4.30%, P = 0.012) probably reflects long‐lasting genetic isolation during the Pleistocene, as limited genetic admixture was found. In accordance with genetic analysis, the biometric investigations indicated a high level of morphological divergence between the European and Asian populations of the species, with further differentiation between the populations from the Taurus and Lebanon Mountains. 相似文献
13.
14.
Phylogeography of Pinus tabulaeformis Carr. (Pinaceae), a dominant species of coniferous forest in northern China 总被引:3,自引:0,他引:3
KANGMING CHEN RICHARD J. ABBOTT RICHARD I. MILNE XIN‐MIN TIAN JIANQUAN LIU 《Molecular ecology》2008,17(19):4276-4288
How coniferous trees in northern China changed their distribution ranges in response to Quaternary climatic oscillations remains largely unknown. Here we report a study of the phylogeography of Pinus tabulaeformis, an endemic and dominant species of coniferous forest in northern China. We examined sequence variation of maternally inherited, seed‐dispersed mitochondrial DNA (mtDNA) (nad5 intron 1 and nad4/3–4) and paternally inherited, pollen‐ and seed‐dispersed chloroplast DNA (cpDNA) (rpl16 and trnS‐trnG) within and among 30 natural populations across the entire range of the species. Six mitotypes and five chlorotypes were recovered among 291 trees surveyed. Population divergence was high for mtDNA variation (GST = 0.738, NST = 0.771) indicating low levels of seed‐based gene flow and significant phylogeographical structure (NST > GST, P < 0.05). The spatial distribution of mitotypes suggests that five distinct population groups exist in the species: one in the west comprising seven populations, a second with a north–central distribution comprising 15 populations, a third with a southern and easterly distribution comprising five populations, a fourth comprising one central and one western population, and a fifth comprising a single population located in the north‐central part of the species’ range. Each group apart from the fourth group is characterized by a distinct mitotype, with other mitotypes, if present, occurring at low frequency. It is suggested, therefore, that most members of each group apart from Group 4 are derived from ancestors that occupied different isolated refugia in a previous period of range fragmentation of the species, possibly at the time of the Last Glacial Maximum. Possible locations for these refugia are suggested. A comparison of mitotype diversity between northern and southern subgroups within the north‐central group of populations (Group 2) showed much greater uniformity in the northern part of the range both within and between populations. This could indicate a northward migration of the species from a southern refugium in this region during the postglacial period, although alternative explanations cannot be ruled out. Two chlorotypes were distributed across the geographical range of the species, resulting in lower levels of among‐population chlorotype variation. The geographical pattern of variation for all five chlorotypes provided some indication of the species surviving past glaciations in more than one refugium, although differentiation was much less marked, presumably due to the greater dispersal of cpDNA via pollen. 相似文献
15.
Drosophila subpulchrella, a new species of the Drosophila suzukii species subgroup from Japan and China (Diptera: Drosophilidae) 总被引:1,自引:0,他引:1
Hisaki TAKAMORI Hide-aki WATABE Yoshiaki FUYAMA Ya-ping ZHANG Tadashi AOTSUKA 《Entomological Science》2006,9(1):121-128
Drosophila (Sophophora) subpulchrella Takamori and Watabe, sp. nov., of the D. suzukii subgroup in the D. melanogaster species group, is described from Japan and southern China, and compared with its sibling species, D. pulchrella Tan et al. distributed in the Yun‐Gui Highland, south‐western China. The results of cross‐experiments show a complete pre‐mating isolation between D. subpulchrella and D. pulchrella. 相似文献
16.
O. Šebesta J. Halouzka Z. Hubálek Z. Juřicová I. Rudolf S. Šikutová P. Svobodová P. Reiter 《Journal of vector ecology》2010,35(1):156-162
Mosquito collections with CDC light traps using dry ice and pigeon‐baited traps were carried out in south Moravia (Czech Republic) from April to October in 2007 and 2008 at two study sites. In 2007, 11 two‐day captures were carried out in two‐week intervals, and 1,490 female mosquitoes of nine species were caught. In 2008, 15 two‐day trappings of mosquitoes were carried out: 6,778 females of 22 species of mosquitoes were trapped. The results showed marked differences in abundance and species composition of mosquitoes between both study sites and between the trapping methods. In the floodplain forest ecosystem of the Soutok study area, Aedes vexans predominated. The species composition in the Nesyt study site was more varied and the most common species was Culex pipiens. At the latter study site, Anopheles hyrcanus (var. pseudopictus) and Uranotaenia unguiculata, mosquito species with largely southern Eurasian distribution, were repeatedly demonstrated. The largest capture of mosquitoes was in traps with CO2 placed at a height 1 m above the ground. The capture of mosquitoes in the pigeon‐baited traps as well as in the traps with CO2 placed in the canopy of trees was markedly lower in both study sites, with the predominant species being Culex pipiens. 相似文献
17.
David E. Kenny Todd M. O'Hara Tai C. Chen Zhiren Lu Xiao Tian Michael F. Holick 《Zoo biology》2004,23(1):33-43
We postulated that dietary ingestion of vitamin D may be used by some Alaskan Arctic marine mammal species in addition to, or instead of, cutaneous production to meet nutritional requirements. Zooplankton (n=5) sampled near Kaktovik, Alaska, contained no measurable vitamin D2 or D3, but did contain provitamin D (7‐dehydrocholesterol), the cutaneous precursor for previtamin D3 in mammals. Fillets and livers from five fish species were sampled near Barrow, Alaska, and evaluated for vitamin D3 content (no vitamin D2 was detected). Differences in vitamin D3 content appeared significant (P≤0.10) among fish livers (Kruskal‐Wallis [H test]=8.25, df=4, P=0.08) and among fish fillets (H=7.80, df=4, P=0.01). We also found significant differences in several pairwise comparisons (Mann‐Whitney U‐test) of vitamin D3 levels in fillets and livers. Blubber from six species of marine mammals had no detectable vitamin D2. The H test results for blubber vitamin D3 concentration were highly significant: 28.12, df=5, P<0.001. There were also significant differences in vitamin D3 content from blubber in pairwise comparisons of primarily invertebrate feeders (bowhead whale (Balaena mysticetus) [mean=4.20 SD±1.10 ng/g], and Pacific walrus (Odobenus rosmarus divergens) [5.43±2.82 ng/g]) vs. primarily piscivorous feeders (ringed seal (Phoca hispida) [746.57±493.00 ng/g] and beluga whale (Delphinapterus leucas) [426.00±174.92 ng/g]) and a semiaquatic terrestrial carnivore (polar bear (Ursus maritimus) [406.17±311.70 ng/g]). The bearded seal (Erignathus barbatus) had intermediate blubber vitamin D3 concentration (156.83±139.25 ng/g), which may reflect an intermediate‐type feeding strategy or an artifact of the small sample size. Zoo Biol 23:33–43, 2004. © 2004 Wiley‐Liss, Inc. 相似文献
18.
Miguel Olvera-Vargas Blanca L. Figueroa-Rangel J. Martín Vázquez-López 《Plant Ecology》2010,211(2):321-335
Detailed information on 38 species and 26 environmental variables was recorded from a network of 86 permanent plots across
a geographical range of 10 km, in order to determine the patterns of floristic composition in Quercus-dominated forests; to elucidate environmental differentiation in such forests; and to determine whether species are partitioning
their environment. To examine likely patterns of floristic composition, a data matrix expressed as relative volume + relative
density was used to run non-metric multidimensional scaling. Canonical correspondence analysis extracted the environmental
variation that best correlates with the observed patterns of floristic composition. Our results indicate that congeneric Quercus individuals represent the largest proportion of the species pool in the study plots. They coexist with other species having
similar ecological requirements in at least three distinct floristic groups. Examination of the two largest groups and their
species compositions reveals that one floristic gradient runs across the most xeric zone of the study area, and the second
major floristic gradient runs across a mesic zone. The most important environmental variable explaining the observed patterns
of floristic composition is altitude, although partial canonical correspondence analysis suggests that micro-habitat heterogeneity
(catena position and canopy maturity) was most significant. 相似文献
19.
To enhance the understanding of larval dispersal in marine organisms, species with a sedentary adult stage and a pelagic larval phase of known duration constitute ideal candidates, because inferences can be made about the role of larval dispersal in population connectivity. Members of the immensely diverse marine fauna of the Indo‐Malay Archipelago are of particular importance in this respect, as biodiversity conservation is becoming a large concern in this region. In this study, the genetic population structure of the pink anemonefish, Amphiprion perideraion, is analyzed by applying 10 microsatellite loci as well as sequences of the mitochondrial control region to also allow for a direct comparison of marker‐derived results. Both marker systems detected a strong overall genetic structure (ΦST = 0.096, P < 0.0001; mean Dest = 0.17; FST = 0.015, P < 0.0001) and best supported regional groupings (ΦCT = 0.199 P < 0.0001; FCT = 0.018, P < 0.001) that suggested a differentiation of the Java Sea population from the rest of the archipelago. Differentiation of a New Guinea group was confirmed by both markers, but disagreed over the affinity of populations from west New Guinea. Mitochondrial data suggest higher connectivity among populations with fewer signals of regional substructure than microsatellite data. Considering the homogenizing effect of only a few migrants per generation on genetic differentiation between populations, marker‐specific results have important implications for conservation efforts concerning this and similar species. 相似文献
20.
The role of hemiparasitic plants: influencing tallgrass prairie quality,diversity, and structure
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Jane P. DiGiovanni William P. Wysocki Sean V. Burke Melvin R. Duvall Nicholas A. Barber 《Restoration Ecology》2017,25(3):405-413
Wood betony, Orobanchaceae (Pedicularis canadensis) and bastard toadflax, Santalaceae (Comandra umbellata) are two root‐hemiparasitic plant species found in tallgrass prairie communities. Natural resource managers are interested in utilizing these species as “pseudograzers” in grasslands to reduce competitively dominant grasses and thereby increase ecological diversity and quality in prairie restorations and urban plantings. We performed an observational field study at 5 tallgrass prairie sites to investigate the association of hemiparasite abundance with metrics of phylogenetic and ecological diversity, as well as floristic quality. Although no reduction in C4 grasses was detected, there was a significant association between hemiparasite abundance and increased floristic quality at all 5 sites. Hemiparasite abundance and species richness were positively correlated at one restoration site. In a greenhouse mesocosm experiment, we investigated response to parasitism by P. canadensis in 6 species representing different plant functional groups of the tallgrass prairie. The annual legume partridge pea, Fabaceae (Chamaecrista fasciculata) had the greatest significant dry biomass reduction among 6 host species, but the C4 grass big bluestem, Poaceae (Andropogon gerardii) had significantly greater aboveground biomass when grown with the hemiparasite. Overall, host species biomass as a total community was significantly reduced in mesocosms, consistent with other investigations that demonstrate influence on community structure by hemiparasitic plant species. Although hemiparasites were not acting as pseudograzers, they have the potential to influence community structure in grassland restorations and remnants. 相似文献