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1.
Four populations of Saponaria bellidifolia situated at the species’ northern range periphery (Apuseni Mountains, southeastern Carpathians) were monitored over a period
of 5 years. They were chosen to represent different habitat types (rocky, fixed screes, open screes and grassy), disturbance
regime (fire), and population sizes (categorized as large and small). The reproductive effort was quantified, and matrix models
were used to describe the population dynamics and to assess population viability. Saponaria bellidifolia had very stable population dynamics in the harsh and stable abiotic conditions of the outcrops where populations occur. Habitat
conditions exerted a notable influence on the species’ population reproductive performance, growth rate, and vital rates,
whereas population size and climate did not have a clear-cut effect on the dynamics of the species. Saponaria bellidifolia maintains viable populations in the southeastern Carpathians, at its northern range periphery. 相似文献
2.
Sébastien Regnaut Philippe Christe Michel Chapuisat Luca Fumagalli 《Conservation Genetics》2006,7(5):665-674
The role that kin selection might play in the evolution of lekking in birds remains controversial. Recent molecular data suggest that males displaying on leks are related. Here we investigated the genetic structure and pattern of relatedness on leks of a declining population of capercaillie (Tetrao urogallus) using microsatellite genetic markers. Since the species is highly sensitive to disturbance, we adopted a non-invasive method by using faecal samples collected in the field. Based on a dataset of 50 males distributed in 6 sub-populations, we found significant genetic structuring among sub-populations, and a significant pattern of isolation by distance among leks. Estimates of relatedness showed that males displaying on the same lek were related, even when controlling for the effects of genetical differentiation among sub-populations. In addition, the frequency distribution of relatedness values indicated that leks contain a mixture of close kin and unrelated individuals (34 and 66%, respectively). This pattern is consistent with the hypothesis that leks often contain kin associations, which might be due to very restricted dispersal of some of the males or to joint dispersal of kin. The results are discussed with respect to their implication for the conservation of endangered populations. 相似文献
3.
Tropical trees are generally long-lived making it difficult to assess the long-term effects of habitat fragmentation on genetic
diversity. Maintenance of genetic diversity in fragmented landscapes is largely dependent on the species’ mating system and
the degree of genetic connectivity (seed and pollen flow) among fragments. Currently, these parameters are largely unknown
for many endangered tropical tree species. Additionally, landscape fragmentation may isolate tropical tree populations from
larger, more continuous populations. The role of isolated individuals in pollen transfer within and between remnant populations
is not clear. In this study, we estimate the mating system and pollen flow patterns in continuous and remnant populations
of the endangered tropical tree Guaiacum sanctum (Zygophyllaceae). Fractional paternity analyses were used to estimate average gene flow distances between fragmented remnant
populations and the siring success of an intermediately located, but isolated individual. In these populations, G. sanctum is a mixed-mating species (t
m = 0.72 − 0.95) whose pollen is transported over large distances (>4 km). An isolated tree may have functioned as a stepping-stone
between two clusters of individuals, assisting long-distance pollen movement. This individual also sired a disproportionately
high number of seeds (13.9%), and is thus an important component of the reproductive success of these populations, thus rejecting
Janzen’s “living-dead” hypothesis. The high levels of genetic diversity maintained as a consequence of long-distance pollen-flow
suggest that this endangered species may have the potential for future adaptation and population expansion if suitable habitats
become available. 相似文献
4.
Olivier Duriez Jean-Marie Sachet Emmanuel Ménoni Nathalie Pidancier Christian Miquel Pierre Taberlet 《Conservation Genetics》2007,8(3):513-526
The Western capercaillie (Tetrao urogallus) is a keystone species of Palearctic boreal and altitude coniferous forests. With the increase of mountain leisure activities
and habitat loss, populations are declining in most mountain ranges in Western Europe. Recent work has shown that the populations
from the Pyrenees and Cantabrian Mountains survived a severe bottleneck during the 19th century, and are still considered
as threatened due to habitat fragmentation and isolation with other populations. We present an extensive phylogeographic study
based on mitochondrial DNA sequence (control region) extracted non-invasively from faeces collected throughout the species
range (from western European mountains to central and eastern Europe, Fenno-Scandia, Russia and Siberia). We also compared
our results with DNA sequences of closely related black-billed capercaillie (T. parvirostris). We found that populations from Pyrenees and Cantabrians are closely related but are different from all other capercaillie
populations that form a homogenous clade. Therefore, we consider that these South-Western populations should be considered
as forming an Evolutionary Significant Unit that needs an appropriate management at a local scale. We also discuss the possible
locations of glacial refugia and subsequent colonisation routes in Eurasia, with a Western “aquitanus” lineage from Iberia and Balkans, and an Eastern “urogallus” lineage from Southern Asia. This work might have important implication for capercaillie conservation strategies to define
important areas for conservation, and to prevent possible exchange or introductions of individuals originated from other lineages.
Electronic Supplementary Material The online version
of this article (doi: ) contains supplementary material, which is available to authorized users. 相似文献
5.
Eggenberg S. and Landolt E. 2006. For which plant species does Switzerland have an international responsibility? Bot. Helv.
116: 119 – 133.
Priorities in plant species conservation are often based on national Red Lists. In an international context, however, the
Red List status (threat) of a species within a limited territory may be misleading because the local disappearance of a species
may or may not have serious implications for its global persistence. A second important aspect to consider in species conservation
is therefore the responsibility of a country for the species, i.e. the importance of the conservation of local populations
for the persistence of the species worldwide. In this contribution, we assess the responsibility of Switzerland for its vascular
flora using three biogeographical criteria: (1) the Swiss portion of the species range (high responsibility for species with
a large fraction of the range in Switzerland), (2) the degree of endemism (high responsibility for species with a small total
range) and (3) the degree of isolation (high responsibility for isolated outposts, which may contain a large part of a species’
genetic variation). The three criteria were derived for each species from global and European distribution maps, and were
then combined to an overall index of responsibility. On this basis, 397 taxa for which Switzerland has an intermediate to
high international responsibility were identified. These are almost 15% of the whole vascular flora of Switzerland. Of the
397 taxa, 75% are endemic species of the Alps, and 48% are threatened taxa within Switzerland. The Responsibility List can
be used together with the Red List to set priorities in plant conservation or to identify areas of particular floristic value.
Manuskript angenommen am 11. September 2006 相似文献
6.
Rosane G. Collevatti Jo?o Carlos Nabout Jose Alexandre F. Diniz-Filho 《Tree Genetics & Genomes》2011,7(6):1237-1247
Many species have suffered reduction in habitable area due to recent climate change, but few studies evaluated how these range
collapses will impact genetic diversity. Here, we modeled shifts in the species’ geographical range to evaluate how genetic
diversity of Caryocar brasiliense will change as a consequence of predicted climate change in the next 50 years. A total of 135 records of species occurrence
were obtained to model species’ distribution based on the current environment using MAXENT and forecasting future distribution
using a combination of three coupled atmospheric–oceanic global circulation models. Genetic parameters were estimated based
on the polymorphism at ten microsatellite loci for 466 individuals. Our results show that climatic suitable areas for C. brasiliense will be restricted to the southernmost distribution of savanna vegetation. Genetic diversity and the number of alleles may
decrease slowly if populations persist in regions up to 0.5 of environmental suitability estimated by MAXENT, but will sharply
decrease above this level. Nevertheless, deviation from mutation–drift equilibrium is significant even if a small amount of
local populations is lost. More climatic suitable areas in the future will be in the most disturbed regions in Brazil, and
populations that will persist there are those with higher levels of inbreeding at present. This may impose several threats
to the species, including the limited capacity to cope with ongoing climatic changes by adaptation and constraints to dispersal. 相似文献
7.
The scale of resource specialization and the distribution and abundance of lycaenid butterflies 总被引:3,自引:0,他引:3
J. B. Hughes 《Oecologia》2000,123(3):375-383
Numerous hypotheses have been proposed for the commonly observed, positive relationship between local abundance and geographic
distribution in groups of closely related species. Here I consider how hostplant specialization and abundance affect the relative
abundance and distribution of lycaenid butterflies (Lepidoptera: Lycaenidae). I first discuss three components of specialization:
local specialization, turnover of specialization across a species’ range, and the minimum number of resources (or habitats)
required by a species. Within this framework, I then consider one dimension of a lycaenid species’ niche, larval hostplant
specialization. In a subalpine region of Colorado, I surveyed 11 lycaenid species and their hostplants at 17 sites. I compare
this local information to continental hostplant use and large-scale distributions of the lycaenids and their hostplants. Local
abundance of a lycaenid species is positively correlated with its local distribution (the number of sites occupied), but not
with its regional or continental distribution. Neither local specialization (the number of hostplants used within one habitat)
nor continental specialization (the number of hostplants used across many habitats) is correlated with local lycaenid abundance.
Continental specialization is positively correlated with a species’ continental distribution, however. Finally, while generalist
butterflies tend to have more hostplant available to them, differences in resource availability do not explain the differences
in butterfly abundance. Although local abundance is correlated only with local distribution, I suggest that abundance-distribution
relationships might emerge at regional and continental scales if local abundance were averaged across many habitat types.
Consideration of the scale of a species’ resource specialization (within or among habitats) appears to be key to understanding
the relationships between resource specialization, resource availability, and a species’ abundance and distribution.
Received: 1 September 1999 / Accepted: 12 December 1999 相似文献
8.
We used mitochondrial DNA sequence comparisons to assess range-wide population structure and historical patterns of differentiation
among populations of the bog turtle (Glyptemys muhlenbergii). This species is one of North America’s smallest and most endangered pond turtles, and is currently found in three largely
disjunct groups of populations: in the southern U.S., in the northeast, and in the Finger Lakes and Lake Ontario Plains region
of western and central New York State. All the New York sites and most of the northeastern sites were glaciated during the
Pleistocene. We surveyed 2793 bases pairs of mitochondrial DNA spanning three genes (cytb, nd4, and d-loop) in 41 individuals
from 21 populations throughout most of the bog turtle’s distribution. We found surprisingly low levels of divergence among
populations, even in southern populations that have been hypothesized as refugia during times of climate change. Our data
suggest populations of bog turtle’s suffered a bottleneck, followed by a rapid post-Pleistocene expansion into northern segments
of the species’ range. We discuss historical changes in habitat availability and climate that may have influenced the historical
deployment of lineages in this species, and possible life history traits and habitat dynamics that might also contribute to
the overall low genetic diversity across its range. 相似文献
9.
Briar J. Howes Joseph W. Brown H. Lisle Gibbs Tom B. Herman Stephen W. Mockford Kent A. Prior Patrick J. Weatherhead 《Conservation Genetics》2009,10(2):407-417
The estimation and maintenance of connectivity among local populations is an important conservation goal for many species
at risk. We used Bayesian statistics and coalescent theory to estimate short- and long-term directional gene flow among subpopulations
for two reptiles that occur in Canada as peripheral populations that are geographically disjunct from the core of their respective
species’ ranges: the black ratsnake and the Blanding’s turtle. Estimates of directional gene flow were used to examine population
connectivity and potential genetic source-sink dynamics. For both species, our estimates of directional short- and long-term
gene flow were consistently lower than estimates inferred previously from F
ST measures. Short- and long-term gene flow estimates were discordant in both species, suggesting that population dynamics have
varied temporally in both species. These estimates of directional gene flow were used to identify specific subpopulations
in both species that may be of high conservation value because they are net exporters of individuals to other subpopulations.
Overall, our results show that the use of more sophisticated methods to evaluate population genetic data can provide valuable
information for the conservation of species at risk, including bidirectional estimates of subpopulation connectivity that
rely on fewer assumptions than more traditional analyses. Such information can be used by conservation practitioners to better
understand the geographic scope required to maintain a functional metapopulation, determine which habitat corridors within
a working landscape may be most important to maintain connectivity among subpopulations, and to prioritize subpopulations
with respect to their potential to act as genetic sources within the metapopulation. 相似文献
10.
Restoration of species‐rich grasslands is a key issue of conservation. The transfer of seed‐containing local plant material is a proven technique to restore species‐rich grassland, since it potentially allows to establish genetically variable and locally adapted populations. In our study, we tested how the transfer of local plant material affected the species diversity and composition of restored grasslands and the genetic variation of the typical grassland plant species Knautia arvensis and Plantago lanceolata.For our study, we selected fifteen study sites in southeastern Germany. We analyzed species diversity and composition and used molecular markers to investigate genetic variation within and among populations of the study species from grasslands that served as source sites for restoration and grasslands, which were restored by transfer of green hay and threshed local plant material.The results revealed no significant differences in species diversity and composition between grasslands at source and restoration sites. Levels of genetic variation within populations of the study species Knautia arvensis and Plantago lanceolata were comparable at source and restoration sites and genetic variation among populations at source and their corresponding restoration sites were only marginal different.Our study suggests that the transfer of local plant material is a restoration approach highly suited to preserve the composition of species‐rich grasslands and the natural genetic pattern of typical grassland plant species. 相似文献
11.
Katsutoshi Watanabe Naoyuki Kanagawa Ryo Kakioka Takahiko Itai Seiichi Mori 《Ichthyological Research》2009,56(4):411-416
Population structure and genetic diversity were examined using partial mitochondrial cytochrome b gene sequences of four wild, one reintroduced, and five captive populations of the endangered cyprinid Hemigrammocypris rasborella from three river systems in the easternmost region of the species’ range in Shizuoka Prefecture, central Honshu, Japan. We
detected loss of genetic diversity from portions of the wild and captive populations, as well as suspected nonindigenous haplotypes
in some captive, reintroduced, and even wild populations. Given the population structure revealed, we suggest that the populations
should be managed with consideration for both the endemism and viability (avoidance of inbreeding depression) of the local
populations. 相似文献
12.
Carmen Bouza Jaime Castro Paulino Martínez Rafaela Amaro Carlos Fernández Paz Ondina Adolfo Outeiro Eduardo San Miguel 《Conservation Genetics》2007,8(4):937-948
A genetic analysis of freshwater pearl mussel Margaritifera margaritifera populations from NW Spain, a peripheral area of its European distribution, was carried out using microsatellite markers.
These populations were formerly reported as genetically differentiated on the basis of growth and longevity studies. Ten loci
previously characterized in populations from central Europe were used to comparatively analyze the genetic variability at
the southern edge of the species’ range. Iberian pearl mussel populations showed very low genetic variability and significant
high genetic differentiation. Half of the total genetic diversity observed appeared to be distributed between populations,
which suggested a highly structured adaptive potential in pearl mussel at the southern peripheral distribution of the species.
Population distinctiveness was evidenced by assignment tests, which revealed a high accuracy of individual assignments to
their population of origin. All data suggested low effective population size and major effects of genetic drift on population
genetic structure. In order to avoid further loss of genetic variation in biologically distinctive populations from NW Spain,
prioritization of genetic resources of this species is required for conservation and management. 相似文献
13.
Babak Pilehvar Gholamhasan Veiskarami Kambiz Taheri Abkenar Javad Soosani 《Biodiversity and Conservation》2010,19(12):3361-3374
Managers in conservation biology are continually faced with the dilemma of needing to demonstrate which areas should receive
conservation priority based on the diversity of species contained. Darenasab (Hashtadpahloo) forest catchment with dominated
oak species in Mediterranean forests of Zagross in Iran was chosen as a case study. In order to estimate plant species richness
in different vegetation types at landscape level, field method that sample both trees and herbs strata simultaneously (modified
multi-scale Whittaker plots) was used to make species–area curves. Twenty-one modified multi-scale Whittaker plots (250 m2 area) were located randomly in four vegetation types. Three species–area, species–log (area) and log (species)–log (area)
curves models were constructed. The log (species)–log (area) model had the highest adjusted r2 among others. Based on Jaccard’s coefficient, the pure oak vegetation type was the most heterogeneous (22% overlap), and
the cushion plants vegetation type is the most homogeneous (29% overlap). The slope of species–area curves had the least range
(0.05) and the slope of species–log (area) curves had the largest range (4.38). When the slopes of species–log (area) curves
divided by mean Jaccard’s coefficient, the species–log (area) curves estimated values closest to those observed. The index
of vegetation types contribution to regional diversity for determining conservation priority in off-reserve area, based on
ranking of the observed mean species per plots, slopes of the species–log (area) curves, mean of Jaccard’s coefficient, mean
unique species per plot, and the number of threatened species in each vegetation types were calculated. This composite index
may provide a scientific method to rank vegetation types with high conservation value. 相似文献
14.
We conducted a survey of an endangered and cryptic forest grouse, the capercaillie Tetrao urogallus, based on droppings collected on two sampling occasions in eight forest fragments in central Switzerland in early spring 2009. We used genetic analyses to sex and individually identify birds. We estimated sex-dependent detection probabilities and population size using a modern spatial capture-recapture (SCR) model for the data from pooled surveys. A total of 127 capercaillie genotypes were identified (77 males, 46 females, and 4 of unknown sex). The SCR model yielded atotal population size estimate (posterior mean) of 137.3 capercaillies (posterior sd 4.2, 95% CRI 130–147). The observed sex ratio was skewed towards males (0.63). The posterior mean of the sex ratio under the SCR model was 0.58 (posterior sd 0.02, 95% CRI 0.54–0.61), suggesting a male-biased sex ratio in our study area. A subsampling simulation study indicated that a reduced sampling effort representing 75% of the actual detections would still yield practically acceptable estimates of total size and sex ratio in our population. Hence, field work and financial effort could be reduced without compromising accuracy when the SCR model is used to estimate key population parameters of cryptic species. 相似文献
15.
Species’ geographic ranges may vary in size in response to a change in environmental conditions. The specific genetic consequences
of range expansions are context dependent, largely depending upon the rate of colonisation as well as the origins and numbers
of founders, and the time since colonisation. Like other “charismatic” taxa, such as birds and lepidopterans, the distributions
of odonates (dragonflies and damselflies) are well-known through substantial monitoring programmes co-ordinated by various
societies. The small red-eyed damselfly Erythromma viridulum (Odonata: Zygoptera) has undergone a substantial, northward range expansion in Europe in the last 30 years and has recently-colonised
two distinct areas in the UK. We quantify the immediate genetic consequences of this rapid colonisation by genotyping more
than 1,400 E. viridulum from 39 sites across the northwest margin of this species’ geographic range. Levels of genetic diversity and spatial structure
are impacted by this species recent range expansion and non-equilibrium conditions that drive weak genetic divergence, even
at regional spatial scales. Populations of E. viridulum become less diverse towards the edge of this species’ distribution, presumably as a consequence of colonisation through a
series of founder events. Specifically, there is a significant reduction in genetic diversity in the smallest, most recent
focus of colonisation in the UK; however, there are generally low levels of genetic diversity across this E. viridulum’s northern range margin. While most populations are generally poorly differentiated, E. viridulum nonetheless consists of two distinct lineages that broadly differentiate between eastern and western Europe. Genetic divergence
between the two UK colonisation foci are indicative of distinct immigration events from separate sources; however a general
lack of spatial structure prevents us from pinpointing the specific origins of these migrant damselflies. 相似文献
16.
Northern hemisphere tree species growing at their northern range margins may be particularly responsive to climate change
and could provide important information regarding future broad-scale responses. We analyzed and compared tree-ring data between
five Douglas-fir [Pseudotsuga menziesii var. glauca (Mirb.) Franco] populations growing at the species’ northernmost distribution in British Columbia, Canada, and five populations
located 150 km to the southeast. We quantified climate–growth relationships using uni- and multivariate techniques at different
temporal scales. Our data suggest that (1) even at its northernmost distributions, precipitation limits long-term mature Douglas-fir
radial growth more than temperatures, (2) northernmost Douglas-fir populations are distinct from populations located further
within the species’ range in terms of certain key short-term growth responses, and (3) northernmost Douglas-fir growth sensitivities
to climate may be increasing over time. In the future, mature Douglas-fir productivity in the northern portion of its range
may be primarily limited by precipitation, and responses may be strongest at the species’ range margins. 相似文献
17.
Evidence shows that dam construction has affected faunal species distribution and diversity in the southeastern U.S. However,
the effects of this perturbation on aquatic flora of the region are heretofore uninvestigated. The objective for this research
is to examine the effects of hydroelectric power generation and habitat characteristics on the size and distribution of populations
of Hymenocallis coronaria (J. LeConte) Kunth (Amaryllidaceae), an emergent aquatic plant found in the southeastern United States, and to characterize
its genetic variability in an effort to target conservation priorities. Multiple linear and logistic regression analyses show
that hydropeaking does not have a significant effect on H. coronaria populations located downstream of dams, while other habitat variables associated with the streams are significantly positively
related to population size and distribution. Analysis of 24 populations using seven universal cpDNA markers and six nDNA microsatellite
markers indicates that the genetic structure for both genomes correlates with the location of a major gap in the species’
range, showing deep divergences in haplotype and population dendrograms between eastern and western regions. An AMOVA confirms
that a substantial amount of genetic variation is found among regions, and very little variation is found within regions.
The eastern and western regions have diverged for a significant time period, potentially due to the presence of a gene flow
barrier in the middle of the species’ range caused by sub-standard habitat. Individual drainage basins contain unique cpDNA
haplotypes and should be managed appropriately. 相似文献
18.
Bruce C. Robertson Tammy E. Steeves Katherine P. McBride Sharyn J. Goldstien Murray Williams Neil J. Gemmell 《Conservation Genetics》2007,8(6):1431-1440
Translocation of individuals among extant populations is an important tool in species conservation that allows managers to
supplement dwindling populations and potentially alleviate the deleterious effects of inbreeding. Ideal translocation strategy
should consider historical relationships among existing populations to avoid potential disruption of population subdivision
and local adaptation. Here, we examine mitochondrial sequence variation in the endangered blue duck Hymenolaimus malacorhynchos, a New Zealand endemic riverine specialist, to facilitate informed decision making in future translocations. Behavioural
observations suggest that blue duck dispersal is limited and may result in genetic structure within and between regional populations.
We analysed 894 base pairs of mitochondrial control region in 78 adult blue ducks sampled from 11 river catchments across
the species’ range (representing four regions in the North Island and three regions in the South Island) and found strong
and significant genetic structure both within and among islands. These results, combined with a 2.0% sequence divergence between
islands, indicates that North Island and South Island blue ducks should be treated as separate management units. The relationship
between genetic differentiation and geographic distance for blue ducks on the South Island conformed to an “isolation by distance”
pattern. Overall, we recommend that translocations of blue ducks should not be made between the North and the South Islands
and those within each island should be restricted to neighbouring catchments. 相似文献
19.
In fragmented landscapes, small populations may be subjected to inbreeding or genetic drift. Gene flow is expected to alleviate
the burden of deleterious mutations in such populations. The beneficial effects of outcrossing may, however, depend on life
history characteristics such as the species’ breeding system. Frequent selfing is expected to purge (sub)lethal alleles and
mitigate inbreeding depression, at least if the load of mildly deleterious mutations has not accumulated through genetic drift
in populations with a small effective size. Gene-inflow from distant source populations can cause outbreeding depression due
to genomic incompatibilities. We tested these predictions using highly fragmented populations of the self-compatible forest
herb Geum urbanum. Assessment of mating system parameters using microsatellite markers inferred high selfing rates (92.5%), confirming the
predominantly self-fertilizing character of the study species. We conducted experimental pollinations with self and outcross
pollen collected from populations at different distances from the target populations. There were no significant signs of inbreeding
depression, even in very small target populations. Except for a minor negative effect on the germination rate for the long-distance
crosses, we found no effects of outbreeding on fitness estimates. 相似文献
20.
Darlina Md. Naim Sandra Telfer Stephanie Sanderson Stephen J. Kemp Phillip C. Watts 《Conservation Genetics》2011,12(4):971-979
Mating behaviour is an important component of species’ life histories. Knowledge of natural patterns of mating can lead also
to more effective management strategies for populations of conservation concern. Despite a high conservation profile many
aspects of the biology of the common dormouse (Muscardinus avellanarius) remain unknown, potentially limiting present conservation efforts. We determine the mating behaviour of M. avellanarius at two woodland sites in the UK: (1) Bontuchel (a natural population in Wales) and (2) Wych (a population in England that
was established by reintroducing captive-bred animals) by genotyping mothers and litters at a panel of 10 microsatellite loci.
Adult female body weight positively correlates with litter size and no apparent reproductive skew was evident. We found that
multiple mating by female dormice is prevalent at both sites, with litters containing three or more offspring sired by multiple
fathers; moreover, multiple mating is adopted by released animals even after a period of captive breeding where females are
mated singly or as a breeding pair. We also present evidence for low proportion of fathers identified in our samples that
probably related to unsampled individuals and/or larger than anticipated population sizes. This first report of mating behaviour
in M. avellanarius highlights the role of genetic studies to uncover species’ reproductive behaviours and include these data for conservation
management. 相似文献