共查询到20条相似文献,搜索用时 15 毫秒
1.
When estimating the size of seabird populations, count data may be biased due to various factors such as detection probability.
Failing to account for detection probability in surveys may lead to an underestimate of population size and may compromise
the ability to monitor trends if detection probability varies among surveys. Here, we use the double-observer method to estimate
detection probability of cavity-nesting snow petrels (Pagodroma nivea) and Wilson’s storm petrels (Oceanites oceanicus) in East Antarctica. Estimates of single-visit detection probability of nesting/roosting adult snow petrels during the incubation
stage of the breeding cycle ranged from 0.86 (SE = 0.04) to 0.87 (SE = 0.04) depending upon observers. Both observers found
snow petrel chicks were easier to detect than adults, with estimated detection probability for chicks ranging from 0.92 (SE = 0.03)
to 1.00 (SE = 0.34 × 10−5). Detection probability of adult and chick snow petrels increased as cavity volume increased. Compared to snow petrels, estimated
detection probability was considerably lower for nesting/roosting Wilson’s storm petrels, ranging from 0.27 (SE = 0.09) to
0.50 (SE = 0.13) for each observer. These estimates of detection probability apply only to those individuals in the population
that were potentially viewable or audible. Nevertheless, our results indicate that double-observer counts for ground surveys
of cavity-nesting seabirds should improve estimates of population abundance in comparison with single-visit counts. Accounting
for observer effects, habitat characteristics and stage of the breeding season on detection probability should also improve
estimation of population trends. 相似文献
2.
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
3.
《Journal of thermal biology》2001,26(4-5):287-293
Two patterns of heterothermia were demonstrated for three species of pigeons (Columbidae): Controlled hyperthermia as a physiological strategy of the arid-adapted Australian Diamond Dove and African Namaqua Dove to minimize heat stress when exposed to high temperatures and Torpor as an energy-saving mechanism at low environmental temperatures. This mechanism was most pronounced in the fruit-eating Cloven-feathered Dove (minimal body temperature Tb=25°C, reduction of metabolic rate by 67%). Hence, heterothermia is regarded as a means of adaptation to variable and unpredictable environmental conditions, playing an important role in the ecological radiation of the Columbidae. 相似文献
4.
Shawna J. Zimmerman Cameron L. Aldridge Kathryn M. Langin Gregory T. Wann R. Scott Cornman Sara J. Oyler-McCance 《Heredity》2021,126(1):117
The warming climate will expose alpine species adapted to a highly seasonal, harsh environment to novel environmental conditions. A species can shift their distribution, acclimate, or adapt in response to a new climate. Alpine species have little suitable habitat to shift their distribution, and the limits of acclimation will likely be tested by climate change in the long-term. Adaptive genetic variation may provide the raw material for species to adapt to this changing environment. Here, we use a genomic approach to describe adaptive divergence in an alpine-obligate species, the white-tailed ptarmigan (Lagopus leucura), a species distributed from Alaska to New Mexico, across an environmentally variable geographic range. Previous work has identified genetic structure and morphological, behavioral, and physiological differences across the species’ range; however, those studies were unable to determine the degree to which adaptive divergence is correlated with local variation in environmental conditions. We used a genome-wide dataset generated from 95 white-tailed ptarmigan distributed throughout the species’ range and genotype–environment association analyses to identify the genetic signature and environmental drivers of local adaptation. We detected associations between multiple environmental gradients and candidate adaptive loci, suggesting ptarmigan populations may be locally adapted to the plant community composition, elevation, local climate, and to the seasonality of the environment. Overall, our results suggest there may be groups within the species’ range with genetic variation that could be essential for adapting to a changing climate and helpful in guiding conservation action.Subject terms: Ecological genetics, Evolutionary ecology 相似文献
5.
Jon Olav Vik Christian N. Brinch Stan Boutin Nils Christian Stenseth 《Population Ecology》2008,50(3):267-274
The classic fur trade records on Canadian lynx (Lynx canadensis) have rarely been analysed in direct conjunction with data on its principal prey, the snowshoe hare (Lepus americanus). Comparable long-term data for hare exist only for a region south of Hudson Bay. We fitted a bivariate log-linear time-series
model to this hare and lynx data to disentangle the within- and between-population interactions of these species. To reduce
problems with fur returns being non-normal and non-linearly related to abundance, we transformed the fur returns to a normal
distribution based on sample quantiles. The estimated effect on next year’s lynx abundance of a 1% increase in current hare
abundance was a 0.23% (SE = 0.05) increase in lynx. Conversely, a 1% increase in current lynx abundance corresponded to a
0.46% (SE = 0.12) decrease in next year’s hare abundance. This contrasts with some earlier studies. However, these studies
mixed hare data from south of Hudson Bay with lynx totals for all of Canada. Despite this asymmetry of interaction strengths,
coefficients of determination were similar for hare versus lynx and lynx versus hare, because hare abundance varies more than
lynx. Both species showed clear intraspecific density-dependence of about equal strength. A 1% increase in current abundance
increased next year’s abundance by about 0.75%.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
6.
David Monticelli Ricardo Ceia Ruben Heleno Hugo Laborda Sergio Timóteo Daniel Jare?o Geoff M. Hilton Jaime A. Ramos 《Journal of Ornithology》2010,151(3):627-636
This paper reports analyses of a capture–mark–recapture (CMR) dataset of 149 Azores Bullfinches ringed on S?o Miguel island
(Azores) between 2005 and 2007, and recaptured–resighted on a monthly basis over a 4-year period (2005–2008) throughout their
breeding range. We examined the effect of time, age (adults vs. juveniles), gender (adult males and females), and environmental
covariates (temperature, rainfall, NAO index) on survival probabilities. The modelling found a high and constant monthly survival
probability (mean ± SE) estimated at 0.96 ± 0.01, similar between both adults and juveniles and independent of environmental
conditions and gender. These findings agree with expectations from island-based life-history theory where relatively mild
conditions and lack of predators should favour high survival rates to compensate for the low reproductive output. The annual
survival rate was estimated at 0.62, which was also consistent with this pattern when compared with survival estimates of
mainland bullfinch and passerine species on other subtropical islands obtained in similar CMR studies. Based on a canonical
estimator, the size of the studied population (mean ± SE) was estimated at 1608 ± 326 individuals. Given that the population
size was only around 120–400 individuals in the early 1990s, we suggest that the high survival probabilities currently applying
to this critically endangered species may have substantially contributed to the recent recovery of this population. Future
research studies on the species’ demography should continue to monitor survival in order to measure the effect of management
interventions currently taking place within the range of the Azores Bullfinch, including the restoration of the biodiversity
rich laurel forest, but also focusing on nest success, which is important for understanding population dynamics. 相似文献
7.
Aconophora compressa is a gregarious, sap-sucking insect that uses multiple host plant species. Nymphal host plant species (and variety) significantly
affected nymphal survival, nymphal development rate and the subsequent size and fecundity of adults, with fiddlewood (Citharexylum spinosum) being significantly best in all respects. Nymphs that developed on a relatively poor host (Duranta erecta var “geisha girl”) and which were moved to fiddlewood as adults laid significantly fewer eggs (mean ± SE = 836 ± 130) than
those that developed solely on fiddlewood (1,329 ± 105). Adults on geisha girl, regardless of having been reared as nymphs
on fiddlewood or geisha girl, laid significantly fewer eggs (342 ± 83 and 317 ± 74, respectively) than adults on fiddlewood.
A simple model that incorporates host plant related survival, development rate and fecundity suggests that the population
dynamics of A. compressa are governed mainly by fiddlewood, the primary host. The results have general implications for understanding the population
dynamics of herbivores that use multiple host plant species, and also for the way in which weed biological control host testing
methods should be conducted.
Handling Editor: Robert Glinwood 相似文献
8.
Anu Valtonen Reima Leinonen Juha Pöyry Heikki Roininen Jukka Tuomela Matthew P. Ayres 《Global Change Biology》2014,20(1):16-27
The magnitude and direction of phenological shifts from climate warming could be predictably variable across the planet depending upon the nature of physiological controls on phenology, the thermal sensitivity of the developmental processes and global patterns in the climate warming. We tested this with respect to the flight phenology of adult nocturnal moths (3.33 million captures of 334 species) that were sampled at sites in southern and northern Finland during 1993–2012 (with years 2005–2012 treated as an independent model validation data set). We compared eight competing models of physiological controls on flight phenology to each species and found strong support for thermal controls of phenology in 66% of the species generations. Among species with strong thermal control of phenology in both the south and north, the average development rate was higher in northern vs. southern populations at 10 °C, but about the same at 15 and 20 °C. With a 3 °C increase in temperature (approximating A2 scenario of IPPC for 2090–2099 relative to 1980–1999) these species were predicted to advance their phenology on average by 17 (SE ± 0.3) days in the south vs. 13 (±0.4) days in the north. The higher development rates at low temperatures of poleward populations makes them less sensitive to climate warming, which opposes the tendency for stronger phenological advances in the north from greater increases in temperature. 相似文献
9.
M. R. L. Jones 《Reviews in Fish Biology and Fisheries》2007,17(2-3):493-499
A review of historical trawl data for orange roughy on Chatham Rise and Challenger Plateau, New Zealand, between the years
1984 and 1996 infers a shift in this species’ diet, with a progressive decline in the percentage occurrence of squid being
apparent. On Chatham Rise, this decline in the percentage occurrence of squid appears to be compensated for by increases in
the percentage occurrence of fish and crustaceans in orange roughy diet, whereas on Challenger Plateau, decreases in all of
squid, fish and crustaceans are apparent. New orange roughy dietary data for 2004 from Chatham Rise is consistent with earlier
data series, with further declines in the percentage occurrence of squid apparent. Declines in the occurrence of squid in
the diet of orange roughy could be attributed to declines in the abundance of squid as a consequence of fisheries activity. 相似文献
10.
Sanna Boman Alessandro Grapputo Leena Lindström Anne Lyytinen Johanna Mappes 《Biological invasions》2008,10(7):1135-1145
Predicting the spread of invasive species is a challenge for modern ecology. Although many invasive species undergo genetic
bottlenecks during introduction to new areas resulting in a loss of genetic diversity, successful invaders manage to flourish
in novel environments either because of pre-adaptations or because important traits contain adaptive variation enabling rapid
adaptation to changing conditions. To predict and understand invasion success, it is crucial to analyse these features. We
assessed the potential of a well-known invader, the Colorado potato beetle (Leptinotarsa decemlineata), to expand north of its current range in Europe. A short growing season and harsh overwintering conditions are apparent
limiting factors for this species’ range. By rearing full-sib families from four geographically distinct populations (Russia,
Estonia, Poland, Italy) at two fluctuating temperature regimes, we investigated (a) possible differences in survival, development
time, and body size among populations and (b) the amount of adaptive variation within populations in these traits. All populations
were able to complete their development in cooler conditions than in their current range. A significant genotype–environment
interaction for development time and body size suggests the presence of adaptive genetic variation, indicating potential to
adapt to cooler conditions. The northernmost population had the highest survival rates and fastest development times on both
temperature regimes, suggesting pre-adaptation to cooler temperatures. Other populations had minor differences in development
times. Interestingly, this species lacks the classical trade-off between body size and development time which could have contributed
to its invasion potential. This study demonstrates the importance of considering both ecological and evolutionary aspects
when assessing invasion risk. 相似文献
11.
Every species is limited both geographically and ecologically to a subset of available habitats, yet for many species the causes of distribution limits are unknown. Temperature is thought to be one of the primary determinants of species distributions along latitudinal and altitudinal gradients. This study examined leaf physiology and plant performance under contrasting temperature regimes of sister species of monkeyflower, Mimulus cardinalis and Mimulus lewisii (Phrymaceae), that differ in altitude distribution to test the hypothesis that temperature is the primary determinant of differences in fitness versus altitude. Each species attained greatest aboveground biomass, net photosynthetic rate, and effective quantum yield of photosystem II when grown under temperatures characteristic of the altitudinal range center. Although both species exhibited greater stem length, stomatal conductance, and intercellular CO2 concentration in hot than in cold temperatures, these traits showed much greater reductions under cold temperature for M. cardinalis than for M. lewisii. Survival of M. lewisii was also sensitive to temperature, showing a striking decrease in hot temperatures. Within each temperature regime, the species native to that temperature displayed greatest growth and leaf physiological capacity. Populations from the altitude range center and range margin of each species were used to examine population differentiation, but central and marginal populations did not differ in most growth or leaf physiological responses to temperature. This study provides evidence that M. cardinalis and M. lewisii differ in survival, growth, and leaf physiology under temperature regimes characterizing their contrasting low and high altitude range centers, and suggests that the species’ altitude range limits may arise, in part, due to metabolic limitations on growth that ultimately decrease survival and limit reproduction.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
12.
The rove beetle Emus hirtus (Linnaeus, 1758) is an endangered habitat specialist, which occurs in long-term cattle pastures where it forages on cattle
dung. We studied this species’ historical and recent altitudinal distribution and habitat requirements in the centre of its
distributional range in the Czech Republic. The species had experienced a sharp decline and was for nearly 20 years considered
as regionally extinct within the Czech Republic. Nowadays, Emus hirtus is present and occurs in relatively high population densities. However, the beetle has shown an uphill shift and is distributed
at significantly higher altitudes in sun-exposed localities in foothills and mountains compared to its historical distribution
in the lowlands. Emus hirtus is one of many organisms that seem to indicate the openness of the pastured woodland landscape in the past. The main reason
for its uphill shift could be habitat loss in densely populated and intensively managed lowlands and restoration of grazing
at higher elevations due to agricultural subsidies. 相似文献
13.
Martin U. Grüebler Fränzi Korner‐Nievergelt Beat Naef‐Daenzer 《Ecology and evolution》2014,4(6):756-765
In migrant birds, survival estimates for the different life‐history stages between fledging and first breeding are scarce. First‐year survival is shown to be strongly reduced compared with annual survival of adult birds. However, it remains unclear whether the main bottleneck in juvenile long‐distant migrants occurs in the postfledging period within the breeding ranges or en route. Quantifying survival rates during different life‐history stages and during different periods of the migration cycle is crucial to understand forces driving the evolution of optimal life histories in migrant birds. Here, we estimate survival rates of adult and juvenile barn swallows (Hirundo rustica L.) in the breeding and nonbreeding areas using a population model integrating survival estimates in the breeding ranges based on a large radio‐telemetry data set and published estimates of demographic parameters from large‐scale population‐monitoring projects across Switzerland. Input parameters included the country‐wide population trend, annual productivity estimates of the double‐brooded species, and year‐to‐year survival corrected for breeding dispersal. Juvenile survival in the 3‐week postfledging period was low (S = 0.32; SE = 0.05), whereas in the rest of the annual cycle survival estimates of adults and juveniles were similarly high (S > 0.957). Thus, the postfledging period was the main survival bottleneck, revealing the striking result that nonbreeding period mortality (including migration) is not higher for juveniles than for adult birds. Therefore, focusing future research on sources of variation in postfledging mortality can provide new insights into determinants of population dynamics and life‐history evolution of migrant birds. 相似文献
14.
We analysed 25 years (1980–2004) of demographic data on a small re-introduced population of endangered African wild dogs (Lycaon pictus) in Hluhluwe-iMfolozi Park (HiP), South Africa, to describe population and pack dynamics. As small populations of cooperative
breeders may be particularly prone to Allee effects, this extensive data set was used to test the prediction that, if Allee
effects occur, aspects of reproductive success, individual survival and population growth should increase with pack and population
size. The results suggest that behavioural aspects of wild dogs rather than ecological factors (i.e. competitors, prey and
rainfall) primarily have been limiting the HiP wild dog population, particularly a low probability of finding suitable mates
upon dispersal at low pack number (i.e. a mate-finding Allee effect). Wild dogs in HiP were not subject to component Allee
effects at the pack level, most likely due to low interspecific competition and high prey availability. This suggests that
aspects of the environment can mediate the strength of Allee effects. There was also no demographic Allee effect in the HiP
wild dog population, as the population growth rate was significantly negatively related to population size, despite no apparent
ecological resource limitation. Such negative density dependence at low numbers indicates that behavioural studies of the
causal mechanisms potentially generating Allee effects in small populations can provide a key to understanding their dynamics.
This study demonstrates how aspects of a species’ social behaviour can influence the vulnerability of small populations to
extinction and illustrates the profound implications of sociality for endangered species’ recovery.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
15.
Gabriela Torres Guy Charmantier David Wilcockson Steffen Harzsch Luis Gimnez 《Ecology and evolution》2021,11(11):7042
Developing physiological mechanistic models to predict species’ responses to climate‐driven environmental variables remains a key endeavor in ecology. Such approaches are challenging, because they require linking physiological processes with fitness and contraction or expansion in species’ distributions. We explore those links for coastal marine species, occurring in regions of freshwater influence (ROFIs) and exposed to changes in temperature and salinity. First, we evaluated the effect of temperature on hemolymph osmolality and on the expression of genes relevant for osmoregulation in larvae of the shore crab Carcinus maenas. We then discuss and develop a hypothetical model linking osmoregulation, fitness, and species expansion/contraction toward or away from ROFIs. In C. maenas, high temperature led to a threefold increase in the capacity to osmoregulate in the first and last larval stages (i.e., those more likely to experience low salinities). This result matched the known pattern of survival for larval stages where the negative effect of low salinity on survival is mitigated at high temperatures (abbreviated as TMLS). Because gene expression levels did not change at low salinity nor at high temperatures, we hypothesize that the increase in osmoregulatory capacity (OC) at high temperature should involve post‐translational processes. Further analysis of data suggested that TMLS occurs in C. maenas larvae due to the combination of increased osmoregulation (a physiological mechanism) and a reduced developmental period (a phenological mechanisms) when exposed to high temperatures. Based on information from the literature, we propose a model for C. maenas and other coastal species showing the contribution of osmoregulation and phenological mechanisms toward changes in range distribution under coastal warming. In species where the OC increases with temperature (e.g., C. maenas larvae), osmoregulation should contribute toward expansion if temperature increases; by contrast in those species where osmoregulation is weaker at high temperature, the contribution should be toward range contraction. 相似文献
16.
Jens von dem Bussche Reto Spaar Hans Schmid Boris Schr?der 《Journal of Ornithology》2008,149(4):529-544
We present here a multiscale modelling approach to predict the current and future spatial distribution of Ring Ouzel (Turdus torquatus) and Blackbird (T. merula) in Switzerland. Species distribution models (SDMs) are applied on three different scales in order to analyse the scale-dependency
of predictors that describe the species’ realised niche. While the models on the macro- and mesoscales (grid of 100 and 1
km2, respectively) cover the entire country, our small-scale models are based on a small set of territories. Ring Ouzels occur
at altitudes above 1000 m a.s.l. only, while Blackbirds occur from the lowlands up to the timberline. Although both species
coexist on the macro- and mesoscales, a direct niche overlap on territory scale is rare. Small-scale differences in vegetation
cover and structure seem to play a dominant role in habitat selection. On the macroscale, however, we observed a high dependency
on bioclimatic variables that mainly represent the altitudinal range and the related forest structure preferred by both species.
Applying the models to climate change scenarios, we predict a decline of suitable habitat for the Ring Ouzel with a simultaneous
median altitudinal shift of 440 m until 2070. In contrast, the Blackbird is predicted to benefit from higher temperatures
and expand its range to higher elevations. Based on the species distribution models we (1) demonstrate the scale-dependency
of environmental predictors, (2) quantify the scale-dependent habitat requirements of Blackbird and Ring Ouzel and (3) predict
the altitudinal range shift of both species as related to climate change scenarios. 相似文献
17.
Evan P. Tanner Jeremy P. Orange Craig A. Davis R. Dwayne Elmore Samuel D. Fuhlendorf 《Ecology and evolution》2019,9(16):9273-9289
Life‐history theory suggests species that typically have a large number of offspring and high adult mortality may make decisions that benefit offspring survival in exchange for increased adult risks. Such behavioral adaptations are essential to understanding how demographic performance is linked to habitat selection during this important life‐history stage. Though studies have illustrated negative fitness consequences to attendant adults or potential fitness benefits to associated offspring because of adaptive habitat selection during brood rearing, equivocal relationships could arise if both aspects of this reproductive trade‐off are not assessed simultaneously. To better understand how adaptive habitat selection during brood rearing influences demographics, we studied the brood survival, attendant parental survival, and space use of two sympatric ground‐nesting bird species, the northern bobwhite (hereafter: “bobwhite”; Colinus virgininanus) and scaled quail (Callipepla squamata). During the 2013–2014 breeding seasons, we estimated habitat suitability across two grains (2 m and 30 m) for both species and determined how adult space use of these areas influenced individual chick survival and parental risk. We found the proportion of a brood's home range containing highly suitable areas significantly increased bobwhite chick survival (β = 0.02, SE = 0.006). Additionally, adult weekly survival for bobwhite was greater for individuals not actively brooding offspring (0.9716, SE = 0.0054) as compared to brooding adults (0.8928, SE = 0.0006). Conversely, brood habitat suitability did not influence scaled quail chick survival during our study, nor did we detect a survival cost for adults that were actively brooding offspring. Our research illustrates the importance of understanding life‐history strategies and how they might influence relationships between adaptive habitat selection and demographic parameters. 相似文献
18.
Gravel pits support waterbird diversity in an urban landscape 总被引:1,自引:1,他引:0
Few studies exist documenting changes in rotifer communities over long time intervals. Here, we explore seasonal and long-term
variation in rotifer communities in four Polish lakes sampled in 1976 and again in 1997. Rarefied, asymptotic species richness
did not differ significantly across study years, although values in 1997 tended to be higher. Simpson’s and Shannon–Wiener
diversity measures provided inconsistent temporal results, with only the former indicating significantly higher richness in
1997. Sorensen’s coefficient of community similarity was as high among lakes in 1976 (0.81) and in 1997 (0.76) as within lakes
across the 21-year span (0.77). Nonlinear redundancy analysis of species’ abundances revealed large, consistent seasonal changes
across lakes, smaller consistent shifts between sampling periods, and small differences between lakes. Collectively, these
metrics indicate that species composition was relatively stable among lakes within years and within lakes between years, while
species’ abundance patterns were far more variable and most affected by season.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Handling editor: S. I. Dodson 相似文献
19.
Although outbreaks of rare species are unusual, several insect species have become emerging pests probably due to the ongoing environmental changes. Barbitistes vicetinus was first described in 1993 as an endemic bush-cricket of north-east Italy and was considered rare until 2008, when it became an established pest, causing severe damages to forests and crops. The possible role of temperature in changing its life cycle has still to be fully understood. Here, we explored the effect of summer temperature on egg diapause and the effect of winter temperature on egg survival. Field observations showed that the proportion of embryos that can complete development at the end of summer ranged from zero to nearly 90% depending on summer temperatures. A substantial shift in the rate of development from 20% to nearly 80% occurred in a thermal range of about 1 °C. On the contrary, overwinter egg survival was high and constant (90%) across a wide range of winter temperatures that go well beyond both the cold and warm thermal limits of the current species range. Overall, the results suggest a potential key role of summer temperature warming on the outbreak propensity of this species that is able to switch from a multiyear to an annual life cycle with just a 1–2 °C warming. 相似文献
20.
Irène Till-Bottraud Bénédicte N. Poncet Delphine Rioux Jacky Girel 《Botanica Helvetica》2010,120(1):53-62
We studied the genetic diversity of the dwarf bulrush (Typha minima) along a 60 km section of the Isère river using AFLP markers. Total clonality was relatively low (proportion of distinguishable
genotypes = 0.70) but extremely variable among populations with one monoclonal population and several populations where all
sampled individuals were different. Genetic diversity was high (He = 0.129) and again variable among populations. Although
no major genetic discontinuity could be detected, gene flow was found to be limited. Our results show a much higher diversity
compared to Swiss populations. The high genetic diversity within most populations despite the species’ potentially important
clonal growth indicates that populations are relatively young. This is in line with the fact that the species lives in open
habitats created by high floods that erase river banks leading to a metapopulation dynamics. However the metapopulation dynamics
is at least partly disturbed as gene flow appears to be restricted so that our populations are probably at risk if no action
is taken to re-establish more natural river flow dynamics. 相似文献