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1.
We studied factors affecting peak densities and amplitudes of fluctuation during 20 annual population fluctuations ofMicrotus pennsylvanicus Ord, 1815 in alfalfa and bluegrass habitats over a 25-year period. Survival was correlated with population density over the
25 years and was the most consistent variable associated with stoppage of population growth. Although not correlated with
population density over the 25 years, a decline in the proportion of reproductively active adult females contributed to cessation
of growth of population fluctuations that peaked in late autumn-winter, and to cessation of growth of eight of eleven population
fluctuations that peaked during summer-early autumn. We conclude variation in survival to be the primary factor affecting
peak densities and amplitudes of population fluctuation ofM. pennsylvanicus. 相似文献
2.
N. N. Timoshkina A. E. Barmintseva A. V. Usatov N. S. Mugue 《Russian Journal of Genetics》2009,45(9):1098-1106
Three populations (Azov, Caspian, and Black Sea) of Russian sturgeon Acipenser queldenstaedtii were tested for polymorphism at nuclear (RAPD and microsatellites) and mitochondrial (PCR identification of two mitotypes)
markers. In addition, morphometric analysis of he representatives of Azov population was carried out. According to the morphological
characters, the Black Sea population occupied an intermediate position between the Caspian and Azov populations, reflecting
the phylogeography of this species. In agreement with the morphometric data, genetic distances (the data of STR analysis)
also placed the Black Sea population between the Caspian and Azov populations (F
ST = 0.058 and 0.043). The genetic distance between the Azov and Caspian population was somewhat higher (F
ST = 0.070). The highest allelic polymorphism at four microsatellite loci was found observed in Caspian population, while the
lowest polymorphism was in the Sea of Azov. RAPD analysis distinguished high polymorphism within the populations, although
it was not feasible for interpopulation analysis. Using the method differentiating the “baerii-like” and typical “gueldenstaedtii”
mitotypes, the absence of the “baerii-like” marker in the Black Sea population was demonstrated. The frequency of this marker
in Caspian and Azov populations constituted 31.1 and 1.8%, respectively. Possible evolutionary reasons for the interpopulation
differences observed are discussed. 相似文献
3.
Tomasz Gortat Alicja Gryczyńska-Siemiątkowska Robert Rutkowski Anna Kozakiewicz Antoni Mikoszewski Michał Kozakiewicz 《Acta theriologica》2010,55(2):109-121
Reduced connectivity among local populations inhabiting a spatially heterogeneous landscape may restrict gene flow and thus
contribute to diminished genetic variation within a population. The aim of this study was to determine the role of geographic
distance and habitat barriers in developing genetic structure of a yellow-necked mouse Apodemus flavicollis (Melchior, 1834) population, taking into consideration the spatial organization of the landscape. A field study was carried
out in two plots located in NE Poland that differed considerably in terms of the scale of habitat fragmentation: (1) a continuous
forest complex, and (2) a mosaic of smaller forest habitats. The plots were separated by a water barrier comprised of a chain
of lakes. DNA samples from a total of 654 individuals were examined by microsatellite analysis (5 loci). The results showed
that the yellow-necked mouse population was characterized by a poorly pronounced genetic structure throughout the study area,
although the statistical significance of F
ST for most location pairs indicated that gene flow in the area was not free. The division of the mouse population into three
genetically distinct groups clearly demonstrated the significant role of water bodies as a natural barrier effectively hindering
free movement of animals and thus gene flow. Analysis of the genetic structure of the mouse population throughout the study
area and also within the distinguished groups indicated that the entire study population may be considered as a single metapopulation.
Our results suggest that geographic distance alone is not the predominant factor affecting the genetic structure of population,
but in the mosaic landscape the relative isolation of individual forest fragments, and barriers hindering movements of individuals
and limiting gene flow among local populations played a much more important role. 相似文献
4.
Krijn B. Trimbos C. J. M. Musters Yvonne I. Verkuil Rosemarie Kentie Theunis Piersma Geert R. de Snoo 《Conservation Genetics》2011,12(3):629-636
With 40% of the European Black-tailed Godwit population breeding in The Netherlands, this country harbours internationally
significant numbers of this species. However, ongoing agricultural intensification has resulted in the fragmentation of the
population and drastic population declines since 1967. By establishing genetic diversity, genetic differentiation and gene
flow on the basis of 12 microsatellites, we investigated whether the population genetic structure of the Dutch Black-tailed
Godwit bears the marks of these changes. Genetic diversity appeared to be moderate, and Bayesian model-based analysis of individual
genotypes revealed no clustering in the Dutch populations. This was supported by pairwise FST values and AMOVA, which indicated no differentiation among the nine breeding areas. Gene flow estimates were larger than
“one migrant per generation” between sample locations, and no isolation by distance was demonstrated. Our results indicate
the maintenance of moderate levels of genetic diversity and genetic connectivity between breeding sites throughout the Dutch
Black-tailed Godwit breeding population. We suggest that the Dutch Black-tailed Godwit breeding areas should be managed as
a single panmictic unit, much as it is presently done. 相似文献
5.
E. L. Ermakov 《Contemporary Problems of Ecology》2011,4(1):35-41
The seasonal dynamics of number and age structure of natural population of Epischura baicalensis Sars, 1900 (Copepoda, Calanoida) from South Baikal was studied using the materials of ten-day sampling of zooplankton samples
in the water layer of 0–250 min 2001–2004. Using ANOVA we determined the statistical significance of seasonal changes in number
and ratio of nauplius larvae, copepodid larvae, and adults. The method of sampling reduction was used to identify the three
phases of population cycle: growth, peak, and depression of number, corresponding to three biological seasons. The importance
of the obtained data is discussed considering the regulating mechanisms for numbers of population of E. baicalensis 相似文献
6.
Shannon E. Pittman Timothy L. King Søren Faurby Michael E. Dorcas 《Conservation Genetics》2011,12(6):1589-1601
In this study, we sought to determine the population stability and genetic diversity of one isolated population of the federally-threatened
bog turtle (Glyptemys muhlenbergii) in North Carolina. Using capture–recapture data, we estimated adult survival and population growth rate from 1992 to 2007.
We found that the population decreased from an estimated 36 adult turtles in 1994 to approximately 11 adult turtles in 2007.
We found a constant adult survival of 0.893 (SE = 0.018, 95% confidence interval, 0.853–0.924) between 1992 and 2007. Using
18 microsatellite markers, we compared the genetic status of this population with five other bog turtle populations. The target
population displayed allelic richness (4.8 ± 0.5) and observed heterozygosity (0.619 ± 0.064) within the range of the other
bog turtle populations. Coalescent analysis of population growth rate, effective population size, and timing of population
structuring event also indicated the genetics of the target population were comparable to the other populations studied. Estimates
of effective population size were a proportion of the census size in all populations except the target population, in which
the effective population size was larger than the census size (30 turtles vs. 11 turtles). We attribute the high genetic diversity
in the target population to the presence of multiple generations of old turtles. This study illustrates that the demographic
status of populations of long-lived species may not be reflected genetically if a decline occurred recently. Consequently,
the genetic integrity of populations of long-lived animals experiencing rapid demographic bottlenecks may be preserved through
conservation efforts effective in addressing demographic problems. 相似文献
7.
Carlos Martorell 《Population Ecology》2007,49(2):115-125
Echeveria longissima, a threatened herb whose habitat has been severely overgrazed and eroded, was studied for three years in a currently grazed
and a fenced area. Matrix population models were used to assess if livestock elimination provides a proper management strategy.
The merits of retrospective perturbation analyses in terms of management planning have been debated. Nevertheless, they may
prove useful when applied in combination with exclosures because they may detect the effects of anthropogenic disturbance
on population dynamics. Thus, the results of retrospective and prospective methods were compared. A rapid decrease in population
size was projected in both areas, even though it was faster in the exposed one. The demographic processes that were favourable
or detrimental in a given year were magnified outside of the fence, but buffered in the exclosure, showing a strong drought-disturbance
synergism. Thus, the largest difference in the population growth rate λ between areas was observed in the driest year. Higher nurse-plant density inside the fence seems to alleviate drought effects.
The use of prospective analysis alone may lead to erroneous management decisions, since the highest elasticities corresponded
to transitions that were favoured by human activities. While allowing for an increased λ in the short term, intervention aimed at increasing these transitions further without attending others that are lessened
by disturbance may introduce large changes in the population dynamics, with negative long-term consequences. Retrospective
methods can detect which processes have been altered by disturbance and its synergisms, so we may more efficiently restore
healthy population dynamics. 相似文献
8.
Rhinolophus mehelyi (Mehely's horseshoe bat) is a vulnerable species with an increasingly fragmented distribution. In Romania, populations of
R. mehelyi have experienced a dramatic decline over the past 50 years, and the current population size is estimated at only 100 adult
individuals inhabiting almost exclusively the Limanu cave. In the present study, we investigated the genetic consequences
of population decline for the viability of the remaining population of R. mehelyi in Romania. We sequenced and analyzed a 359-bp fragment of the mitochondrial control region from the only known Romanian
population and compared it with two geographically close colonies from Bulgaria. A single haplotype was found in the Romanian
population compared to 10 in the Bulgarian population, suggesting genetic isolation. 相似文献
9.
Nikoleta Karaiskou Maria Lappa Stefanos Kalomoiris George Oikonomidis Chariklia Psaltopoulou Theodore J. Abatzopoulos Costas Triantaphyllidis Alexander Triantafyllidis 《Conservation Genetics》2011,12(5):1299-1311
The ability to detect genetic differences both in space and time is crucial for conserving genetic variation. It can reveal
genetic diversity and genetic composition changes of declining native populations that are supported through stocking with
captive bred individuals. The present study was designed to analyse the temporal stability of a declining common carp (Cyprinus carpio) population from Lake Volvi (North Greece). Polymorphism was evaluated using seven microsatellite loci at two sampling time
points (separated by 12 years). The genetic variability of four additional populations (from two rivers and two lakes) in
Northern Greece was also investigated for comparison. Heterozygosity values (0.692–0.868) and allelic richness (8.530–11.148)
were high for all studied populations and comparable to other European populations. However, the analysis of temporal common
carp samples from Lake Volvi revealed a significant change in their genetic composition and admixture analysis demonstrated
significant introgression of stocked individuals into the native population. Both temporal and point estimate methods revealed
low effective size (Ne = 61–171.3) for this population, possibly a result of an ancient genetic bottleneck that led to population decline and/or
recent anthropogenic interventions. This low Ne has rendered the native population vulnerable to alteration of its genetic composition. Our study demonstrates that enhancement
programs should be applied cautiously, especially for small populations. Moreover, it underlines the need for temporal analyses,
which may contribute to the evaluation of previous management policies and to future decision making. 相似文献
10.
G. N. Dorovskikh 《Inland Water Biology》2010,3(2):165-169
The state of populations of the crucian carp Carassius carassius L. and the copepod parasite Lernaea cyprinacea L. was studied after 10 years of a sharp decrease in their abundance. Only one generation of Lernaea cyprinacea species was recorded each year. The alteration of the parasite generation occurred in the second half of July. Changes in
the age structure of the copepod population did not affect the distribution pattern of its abundance in the host population,
but the values of the K exponent changed in accordance with alterations of the parasite generations. By 2007 the sex ratio in the population became
equal, males and females differed in their lengths and weights, and three dimensional groups were found in the catches. It
is thought that males and females of the crucian carp have different roles in the maintenance of the L. cyprinacea abundance. The dominating fish sizes and the level of the host infection by copepods remained the same as in 1997–2003. 相似文献
11.
Aniruddha Majumder Qamar Qureshi Kalyanasundaram Sankar Alok Kumar 《European Journal of Wildlife Research》2017,63(1):17
Long-term monitoring of tiger population is essential in any human-dominated landscape as globally their population is showing a declining trend due to unrelenting stress or stochastic events. In view of that, Bengal tiger population was monitored in Pench Tiger Reserve (Pench), Madhya Pradesh of Central India between May 2006 and April 2013. The population, age-sex ratios, survival rate, growth rate, and recruitment pattern of adult (≥36 month), subadult (≥18 to 36 month), and cubs (≤15 month) were studied using camera trap and radio-telemetry techniques. Overall, tiger density ± SE/100 km2 using Maximum Likelihood Spatial Explicit Capture Recapture method was 5.5 ± 1.6 in first trapping period or year and 3.7 ± 0.8 in last or seventh trapping year. The estimated survival rate of all tiger (n = 66) was 0.66 (±0.04), whereas mean annual growth rate (±SE) was 1.15 (±0.11) i.e. 15%. The sex ratio (male/female) found to be female biased and more than 80% of overall recruitment was contributed by female tiger. The dispersal of subadults in the tiger population contributed gradual fluctuation in survival rate and annual growth rate, as resident adult tiger population remained almost stable over the study period. As the overall tigers are surviving in a small population size and operating at carrying capacity, the important corridors connecting with neighboring population of Kanha Tiger Reserve and Satpura Tiger Reserve may ensure constant emigration and immigration to reduce the chances of genetic drift or inbreeding in the Pench tiger population. 相似文献
12.
Katarína Mihaliková Zora Váradyová Peter Pristaš Peter Javorský Svetlana Kišidayová 《Biologia》2009,64(6):1141-1145
The effects of three heavy metal cations, mercury (II), copper (II), and chromium (VI), on the growth of the rumen ciliate
Entodinium caudatum in vitro culture was studied. The E. caudatum culture was challenged by HgCl2, CuCl2, and K2Cr2O7 for a period of 4 days. The tested concentrations of mercury (II) and copper (II) were 1, 5, 10, 20, 50 mg/L and 2, 10, 20,
40 mg/L for chromium (VI) at single dose with either untreated or inhibited bacterial co-culture population. Effective metal
concentrations required to reduce ciliate growth by 50% (EC50) for mercury (II), copper (II), and chromium (VI) either with untreated or inhibited bacterial co-culture population after
24 h of metal application were 24, 20, and 21 or 15, 20, and 19 mg/L, respectively. After 4 days of metal application, corresponding
EC50 values for mercury (II), copper (II), and chromium (VI) were 16, 20, and 17 (with untreated bacterial population) or not
determinable, 20, and 15 mg/L, respectively (with inhibited bacterial population). Increased sensitivity of E. caudatum to tested heavy metals with inhibited bacterial co-culture population indicate that the ciliate resistance to the heavy metal
tested depends on detoxification abilities of rumen bacterial population. 相似文献
13.
Pedro Teófilo Silva de Moura Luciana Vieira de Paiva Clarisse Carolina de Oliveira Silva Liana Monique Paiva Cavalcante Mauro Pichorim Leonardo Fernandes França 《Population Ecology》2018,60(3):223-235
In tropical dry environments rainfall periodicity may affect demographic parameters, resulting in fluctuations in bird abundance. We used capture–recapture data for the Grey Pileated Finch from a Neotropical dry forest to evaluate the hypothesis that intra- and inter-annual survival, individuals entrance and population abundance, are related to local rainfall. Sampling occurred across 3 years, with individuals captured, tagged and evaluated for age and presence of brood patch every 14 days. Using the POPAN formulation, we generated demographic models to evaluate study population temporal dynamics. Best-fit models indicated a low apparent annual survival in the first year (16%) compared to other years (between 47 and 62%), with this low value associated with an extreme drought. The abundance of juveniles at each capture occasion was significantly dependent on the accumulated precipitation in the previous 14 days, and the juvenile covariate was a strong predictor of the intra-annual entrance probability (natality). Individuals entrance during the reproductive period corresponded to 53, 52 and 75% of total ingress for each year, respectively. The trend in sampled population size indicated positive exponential growth (Ninitial = 50, Nlast = 600), with intra-annual fluctuations becoming progressively more intense. Low survival was relevant during population decline at study onset, while at study end intense Individuals entrance promoted rapid population growth. Thus, the indirect effects of rainfall and the combined effect of two demographic rates operated synergistically on the immediate population abundance of Grey Pileated Finch, an abundant bird in a Neotropical dry forest. 相似文献
14.
Mark A. Paulissen 《Journal of Ethology》2011,29(3):493-497
A previous study showed that little brown skinks, Scincella lateralis, from a population in Louisiana, USA were poor at learning to escape to a specific retreat in a series of laboratory trials.
The study was repeated on little brown skinks from a population in Oklahoma (650 km from the Louisiana population). The Oklahoma
lizards were significantly better at learning to escape to a specific retreat than their Louisiana counterparts. This result
demonstrates that geographic variation in the ability to learn an escape behavior exists in this species. 相似文献
15.
In many species of mammals, adults play an important role in influencing the survival and/or reproduction of juveniles. Adult
males could have a negative effect on population density when their absence becomes a limiting factor in female fertilization.
We tested the hypotheses that the absence of overwintering males (adult males) reduces the population growth rate through
a delay in the onset of reproductive activity of Cohort 1 females in Calomys venustus populations. The study was carried out in two control and two experimental enclosures (0.25 ha). Adult males were removed
after their offspring were born. Weekly trapping sessions were carried out from spring to autumn. To estimate population growth
rates (λ), apparent survival (ϕ) and seniority probability (γ) were estimated using capture–mark-recapture models. Models were constructed with these two parameters and recapture probability
(p) constrained to vary as a function of time, enclosure and/or treatment. We derived estimates of population growth rates through
the estimates of ϕ and γ. The best models for ϕ and γ did not show a treatment effect. Variability between the four enclosures was greater than between control and experimental
enclosures. Enclosures had different growth rates at the beginning of the study but were equaled at the end. Temporal variation
in population growth rates was a result of temporal variation of γ. The two controls showed the highest growth rates earlier in time. The results did not support the hypothesis tested in this
study. It seems that the number of overwintering males do not affect the population growth rate. 相似文献
16.
The golden eagle (Aquila chrysaetos) is an endangered raptor, which is threatened mainly by illegal egg and nestling robbery. Here we describe a fluorescently
labeled, multiplex PCR method using 13 microsatellite markers, which provides a powerful tool for the individual identification
and parentage testing of the Golden eagle. This test should be applicable to both forensic analysis and population studies.
Fifteen polymorphic loci from A. chrysaetos were cross-amplified. Subsequent PCR condition optimization led to the successful co-amplification of 13 different loci in
a single PCR reaction. Fifty samples from wild-living individuals and 89 samples from captive-bred individuals were examined.
The results indicated that both populations have similar levels of moderate inbreeding, unsurprising in a small population.
This probability of excluding a random individual in parentage analysis was 0.9912 for the wild population and 0.9932 in the
captive-bred one in the case that both the individual and its mother were examined together. The probability of identity was
estimated to be 3 × 10−8 for the wild and 4 × 10−8 for the captive-bred populations. Given the size of the Slovak golden eagle population, this test should therefore be sufficient
to reliably identify individual raptors and assess parentage in both conservation studies and forensic analysis. 相似文献
17.
Hayati A Wickneswari R Maizura I Rajanaidu N 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,108(7):1274-1284
A total of 723 accessions of oil palm (Elaeis guineensis Jacq.) from 26 populations representing ten countries in Africa and one Deli dura family were screened for allelic variation at seven enzyme loci from six enzyme systems using starch gel electrophoresis. On average, 54.5% of the loci were polymorphic (0.99 criterion). The average and effective number of alleles per locus was 1.80 and 1.35, respectively. Mean expected heterozygosity was 0.184, with values ranging from 0.109 (population 8, Senegal) to 0.261 (population 29, Cameroon). The genetic differentiation among populations was high (FST=0.301), indicating high genetic divergence. The calculation of FST by geographic zones revealed that the high FST was largely due to FST among populations in West Africa, suggesting diversifying selection in this region. The mean genetic distance across populations was 0.113. The lowest genetic distance (D) was observed between population 5 from Tanzania and population 7 from the Democratic Republic of the Congo (0.000) and the highest was found between population 4 from Madagascar and population 13 from Sierra Leone (0.568). The total gene flow across oil palm populations was low, with an Nm of 0.576, enhancing genetic structuring, as evident from the high FST values. UPGMA cluster analysis revealed three main clusters; the western outlying populations from Senegal and Sierra Leone were in one cluster but separated into two distinct sub-clusters; the eastern outlying populations from Madagascar were in one cluster; the populations from Angola, Cameroon, The Democratic Republic of the Congo, Ghana, Tanzania, Nigeria and Guinea were in one cluster. The Deli dura family seems to be closely related to population 6 from Guinea. Oil palm populations with high genetic diversity—i.e. all of the populations from Nigeria, Cameroon and Sierra Leone, population 6 of Guinea, population 1 of Madagascar and population 2 of Senegal should be used in improvement programmes, whereas for conservation purposes, oil palm populations with high allelic diversity (Ae), which include populations 22 and 29 from Cameroon, populations 39 and 45 from Nigeria, population 6 from Guinea, populations 5 and 13 from Sierra Leone and population 1 from Madagascar should be selected for capturing as much genetic variation as possible.Communicated by D.B. Neale 相似文献
18.
I. Guja S. Łapiński Ł. Migdał S. Pałka T. Ząbek S. N. Sergina 《Russian Journal of Genetics》2016,52(5):517-520
The aim of the research was to establish a microsatellite panel to determine the genetic diversity within the breeding nutria population in Poland. In the study, 92 animals representing six color forms were used. Ten fluorescently labeled microsatellite markers were investigated by multicolored capillary electrophoresis. All the microsatellites were polymorphic. The average heterozygosity observed among the population was 41%. The mean number of alleles per locus was 9.2. The average heterozygosity observed in the whole population was lower than expected. This implies that the nutria population deviates from the Hardy–Weinberg equilibrium. Low M values (from 0.078 to 0.545) of the Garza–Williamson index reveal a reduction of genetic variation in the investigated population and suggest that the breeding nutria population is remnant. 相似文献
19.
The peregrine falcon (Falco peregrinus) population in southern Scandinavia was almost extinct in the 1970’s. A successful reintroduction project was launched in
1974, using captive breeding birds of northern and southern Scandinavian, Finnish and Scottish origin. We examined the genetic
structure in the pre-bottleneck population using eleven microsatellite markers and compared the data with the previously genotyped
captive breeding population and contemporary wild population. Museum specimens between 53 and 130 years old were analyzed.
Despite an apparent loss of historical genetic diversity, the contemporary population shows a relatively high level of genetic
variation. Considerable gene introgression from captive breeding stock used to repopulate the former range of southern Scandinavian
peregrines may have altered the genetic composition of this population. Both the historical and contemporary northern and
southern Scandinavian populations are genetically differentiated. The reintroduction project implemented in the region and
the use of non-native genetic stock likely prevented the southern Scandinavian population from extinction and thus helped
maintain the level of genetic diversity and prevent inbreeding depression. The population is rapidly increasing in numbers
and range and shows no indication of reduced fitness or adaptive capabilities in the wake of the severe bottleneck and the
reintroduction. 相似文献
20.
The altitude-related responses to the increased application of CO2, N, and their combination were investigated in two Abies faxoniana populations, which originated from a subalpine coniferous forest at elevations of 2,580 and 3,200 m using closed-top chambers. The two contrasting populations were subjected to two CO2 regimes (350 and 700 µmol mol?1) and two N levels (0 and 5 g N m?2 year?1). Their net photosynthetic rate, non-structural carbohydrate concentration, and photosynthetic N use efficiency (PNUE) increased under elevated CO2. However, the increases detected in the high-elevation (HE) population were significantly greater than those found in the low-elevation (LE) population. Under elevated CO2 and N application, the maximal carboxylation rate (V cmax) increased in HE population, whereas no effects were found on V cmax in LE population. The C to N ratio decreased under N application in both populations. N application also induced the HE population to show greater increases in free amino acids, soluble proteins, N concentration, and PNUE than LE population. These results suggested that the population from HE was more sensitive to elevated CO2 and (or) N application than LE population. Results of this study provided valuable knowledge for predicting forest development under increased atmospheric CO2 concentration and (or) N deposition. 相似文献