Avoidance mechanisms of three Pieris butterfly species against the parasitoid wasp Apanteles glomerulus

Abstract. 1. Experimental studies have shown that larvae of three Pieris butterflies, P.rapae L., P.melete Mènètriés and P.napi L., are attacked by a parasitoid wasp, Apanteles glomeratus L. Although P.rapae larvae are parasitized heavily in the field, P.melete and P.napi are infrequently parasitized successfully because they possess mechanisms for encapsulating parasitoid larvae and for avoiding parasitism.
2. This study examines spatial and temporal variation in rates of parasitism of the three Pieris species by A.glomeratus in the field. We attempted to determine whether P.rapae possesses any means of avoiding parasitism by this wasp, and then to deduce why both P.melete and P.napi have more distinctive avoidance mechanisms than P.rapae.
3. Our results indicate that in temporary habitats, which are the main habitats of P.rapae, P.rapae is able to escape A.glomeratus in time and space by colonizing new habitats before the parasitoid arrives. In permanent habitats, however, such escape is not possible. P.rapae larvae lack physiological or behavioural avoidance mechanisms of reducing parasitism rates in permanent habitats. P.melete and P.napi , in contrast, live only in permanent habitats, where the parasitic pressure is potentially high, and have evolved active avoidance mechanisms.     

Genetic diversity of the melon aphid <Emphasis Type="Italic">Aphis gossypii</Emphasis> (Hemiptera: Aphididae) in a diversified vegetable growing area

The melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a highly polyphagous species. To investigate its genetic diversity among seasonal host plants, we conducted a field study in a diversified vegetable growing area in Beijing, China. The molecular marker mtDNA COI (1563-bp long) was used to analyze the genetic diversity of aphid populations collected from eight plant species belonging to families Malvaceae, Cucurbitaceae and Rosaceae. A total of 33 haplotypes were identified, five of which were shared haplotypes, while the remaining 28 were unique haplotypes. At least one haplotype was shared by all eight A. gossypii populations. Aphid populations showed high levels of nucleotide and haplotype diversity. The genetic diversity indices were maximal on the hibiscus (the primary host), whereas minimal on cucumber and strawberry (the secondary hosts). The analysis of molecular variance showed that most of the variance was distributed within populations. Based on the genetic distances, the eight populations can be divided into two groups, associated with primary and the secondary host plant, respectively. The aphids possibly migrated from Hibiscus to watermelon, thereafter dispersed from watermelon to other secondary host plants. Watermelon was an important host probably due to its early growing season and large planting area. Our results highlighted the need to target the population dispersal for effective control.     

Species diversity and population density affect genetic structure and gene dispersal in a subtropical understory shrub

Aims The dispersal of pollen and seeds is spatially restricted and may vary among plant populations because of varying biotic interactions, population histories or abiotic conditions. Because gene dispersal is spatially restricted, it will eventually result in the development of spatial genetic structure (SGS), which in turn can allow insights into gene dispersal processes. Here, we assessed the effect of habitat characteristics like population density and community structure on small-scale SGS and estimate historical gene dispersal at different spatial scales.Methods In a set of 12 populations of the subtropical understory shrub Ardisia crenata, we assessed genetic variation at 7 microsatellite loci within and among populations. We investigated small-scale genetic structure with spatial genetic autocorrelation statistics and heterogeneity tests and estimated gene dispersal distances based on population differentiation and on within-population SGS. SGS was related to habitat characteristics by multiple regression.Important findings The populations showed high genetic diversity (H e = 0.64) within populations and rather strong genetic differentiation (F ′ ST = 0.208) among populations, following an isolation-by-distance pattern, which suggests that populations are in gene flow–drift equilibrium. Significant SGS was present within populations (mean Sp = 0.027). Population density and species diversity had a joint effect on SGS with low population density and high species diversity leading to stronger small-scale SGS. Estimates of historical gene dispersal from between-population differentiation and from within-population SGS resulted in similar values between 4.8 and 22.9 m. The results indicate that local-ranged pollen dispersal and inefficient long-distance seed dispersal, both affected by population density and species diversity, contributed to the genetic population structure of the species. We suggest that SGS in shrubs is more similar to that of herbs than to trees and that in communities with high species diversity gene flow is more restricted than at low species diversity. This may represent a process that retards the development of a positive species diversity–genetic diversity relationship.     

Population structure and genetic variation in the endangered Giant Kangaroo Rat (<Emphasis Type="Italic">Dipodomys ingens</Emphasis>)

Populations of the endangered giant kangaroo rat, Dipodomys ingens (Heteromyidae), have suffered increasing fragmentation and isolation over the recent past, and the distribution of this unique rodent has become restricted to 3% of its historical range. Such changes in population structure can significantly affect effective population size and dispersal, and ultimately increase the risk of extinction for endangered species. To assess the fine-scale population structure, gene flow, and genetic diversity of remnant populations of Dipodomys ingens, we examined variation at six microsatellite DNA loci in 95 animals from six populations. Genetic subdivision was significant for both the northern and southern part of the kangaroo rat’s range although there was considerable gene flow among southern populations. While regional gene diversity was relatively high for this endangered species, hierarchical F-statistics of northern populations in Fresno and San Benito counties suggested non-random mating and genetic drift within subpopulations. We conclude that effective dispersal, and therefore genetic distances between populations, is better predicted by ecological conditions and topography of the environment than linear geographic distance between populations. Our results are consistent with and complimentary to previous findings based on mtDNA variation of giant kangaroo rats. We suggest that management plans for this endangered rodent focus on protection of suitable habitat, maintenance of connectivity, and enhancement of effective dispersal between populations either through suitable dispersal corridors or translocations.     

Hierarchical structure of mitochondrial DNA gene flow among humpback whales Megaptera novaeangliae, world-wide

The genetic structure of humpback whale populations and subpopulation divisions is described by restriction fragment length analysis of the mitochondrial (mt) DNA from samples of 230 whales collected by biopsy darting in 11 seasonal habitats representing six subpopulations, or 'stocks', world-wide. The hierarchical structure of mtDNA haplotype diversity among population subdivisions is described using the analysis of molecular variance (AMOVA) procedure, the analysis of gene identity, and the genealogical relationship of haplotypes as constructed by parsimony analysis and distance clustering. These analyses revealed: (i) significant partitioning of world-wide genetic variation among oceanic populations, among subpopulations or 'stocks' within oceanic populations and among seasonal habitats within stocks; (ii) fixed categorical segregation of haplotypes on the south-eastern Alaska and central California feeding grounds of the North Pacific; (iii) support for the division of the North Pacific population into a central stock which feeds in Alaska and winters in Hawaii, and an eastern or 'American' stock which feeds along the coast of California and winters near Mexico; (iv) evidence of genetic heterogeneity within the Gulf of Maine feeding grounds and among the sampled feeding and breeding grounds of the western North Atlantic; and (v) support for the historical division between the Group IV (Western Australia) and Group V (eastern Australia, New Zealand and Tonga) stocks in the Southern Oceans. Overall, our results demonstrate a striking degree of genetic structure both within and between oceanic populations of humpback whales, despite the nearly unlimited migratory potential of this species. We suggest that the humpback whale is a suitable demographic and genetic model for the management of less tractable species of baleen whales and for the general study of gene flow among long-lived, mobile vertebrates in the marine ecosystem.     

Partitioning within‐species variance in behaviour to within‐ and between‐population components for understanding evolution

Phenotypes vary at multiple hierarchical levels, of which the interspecific variance is the primary focus of phylogenetic comparative studies. However, the evolutionary role of particular within‐species variance components (between‐population, between‐ or within‐individual variances) remains neglected. Here, we partition the variance in an anti‐predator behaviour, flight initiation distance (FID), and assess how its within‐ and between‐population variance are related to life history, distribution, dispersal and habitat ecology. Although the composition of within‐species variance in FID depended on the phylogeny, most variance occurred within populations. When accounting for allometry, density‐dependence, uncertainty in the phylogenetic hypothesis and heterogeneity in data quality, within‐population variance was significantly associated with habitat diversity and population size. Between‐population variance was a significant predictor of natal dispersal, senescence and habitat diversity. Accordingly, not only species‐specific mean values of a behavioural trait, but also its variance within and among populations can shape the evolutionary ecology of species.     

Isolated in an ocean of grass: low levels of gene flow between termite subpopulations

Habitat fragmentation is one of the most important causes of biodiversity loss, but many species are distributed in naturally patchy habitats. Such species are often organized in highly dynamic metapopulations or in patchy populations with high gene flow between subpopulations. Yet, there are also species that exist in stable patchy habitats with small subpopulations and presumably low dispersal rates. Here, we present population genetic data for the ‘magnetic’ termite Amitermes meridionalis, which show that short distances between subpopulations do not hinder exceptionally strong genetic differentiation (F_ST: 0.339; R_ST: 0.636). Despite the strong genetic differentiation between subpopulations, we did not find evidence for genetic impoverishment. We propose that loss of genetic diversity might be counteracted by a long colony life with low colony turnover. Indeed, we found evidence for the inheritance of colonies by so‐called ‘replacement reproductives’. Inhabiting a mound for several generations might result in loss of gene diversity within a colony but maintenance of gene diversity at the subpopulation level.     

Should I Stay or Should I Go? Dispersal and Population Structure in Small,Isolated Desert Populations of West African Crocodiles

The maintenance of both spatial and genetic connectivity is paramount to the long-term persistence of small, isolated populations living in environments with extreme climates. We aim to identify the distribution of genetic diversity and assess population sub-structuring and dispersal across dwarfed desert populations of Crocodylus suchus, which occur in isolated groups, usually less than five individuals, along the mountains of Mauritania (West Africa). We used both invasive and non-invasive sampling methods and a combination of mitochondrial DNA (12 S and ND4) and microsatellite markers (32 loci and a subset of 12 loci). Our results showed high genetic differentiation and geographic structure in Mauritanian populations of C. suchus. We identified a metapopulation system acting within four river sub-basins (high gene flow and absence of genetic structure) and considerable genetic differentiation between sub-basins (F _ST range: 0.12–0.24) with rare dispersal events. Effective population sizes tend to be low within sub-basins while genetic diversity is maintained. Our study suggests that hydrographic networks (temporal connections along seasonal rivers during rainy periods) allow C. suchus to disperse and maintain metapopulation dynamics within sub-basins, which attenuate the loss of genetic diversity and the risk of extinction. We highlight the need of hydrographic conservation to protect vulnerable crocodiles isolated in small water bodies. We propose C. suchus as an umbrella species in Mauritania based on ecological affinities shared with other water-dependent species in desert environments.     

Beta diversity of rock-restricted cichlid fishes in Lake Malawi: importance of environmental and spatial factors

The rock-restricted cichlid fish assemblages of Lake Malawi exhibit high spatial diversity in their species composition and relative abundance. However the extent to which this is due to the effects of local environmental differences, dispersal limitation of constituent taxa, and the assignment of allopatric populations to species is uncertain. We examined the factors associated with diversity within an assemblage from the north-western shores, encompassing a spatial scale of 170 km. For both the whole assemblage, and all constituent species-complexes, spatial variance in community structure was significantly dependent upon both geographic distances between locations and local habitat variables. Pronounced effects of distance indicate limited dispersal, but our results also show that that the spatial variance explained by geographic distance alone was strongly linked to proportion of allopatric populations within a species-complex with species status. Thus, the taxonomic status of allopatric populations underlies, at least partially, the biogeographical structure of this assemblage. Substrate composition and habitat depth were also significant determinants of community structure, although spatial variance attributed to these variables was less than that associated with distance alone. Substantial unexplained variance may be a consequence of the effects of unmeasured habitat variables, high ecological similarity between co-occurring species, stochastic influences on population abundance, and the effects of local adaptation. Despite low spatial variance explained by the assessed environmental variables, significant environmental influence on cichlid assemblage structure across a wide spatial scale indicates that even slight future environmental changes may have the capacity to significantly alter species composition.     

RAPD Profiling in Detecting Genetic Variation in Endemic Coelonema (Brassicaceae) of Qinghai-Tibet Plateau of China

Random amplified polymorphic DNA (RAPD) markers were used to measure genetic diversity of Coelonema draboides (Brassicaceae), a genus endemic to the Qilian Mountains of the Qinghai-Tibet Plateau. We sampled 90 individuals in 30 populations of Coelonema draboides from Datong and Huzhu counties of Qinghai Province in P.R. China. A total of 186 amplified bands were scored from the 14 RAPD primers, with a mean of 13.3 amplified bands per primer, and 87% (161 bands) polymorphic bands (PPB) was found. Analysis of molecular variance (AMOVA) shows that a large proportion of genetic variation (84.2%) resides among individuals within populations, while only 15.8% resides among populations. The species shows higher genetic diversity between individuals than other endemic and endangered plants. The RAPDs provide a useful tool for assessing genetic diversity of rare, endemic species and for resolving relationships among populations. The results show that the genetic diversity of this species is high, possibly allowing it to adapt more easily to environmental variations. The main factor responsible for the high level of differentiation within populations and the low level of diversity among populations is probably the outcrossing and long-lived nature of this species. Some long-distance dispersal, even among far separated populations, is also a crucial determinant for the pattern of genetic variation in the species. This distributive pattern of genetic variation of C. draboides populations provides important baseline data for conservation and collection strategies for the species. It is suggested that only populations in different habitats should be studied and protected, not all populations, so as to retain as much genetic diversity as possible.     

Genetic variation of fish parasite populations in historically connected habitats: undetected habitat fragmentation effect on populations of the nematode Procamallanus fulvidraconis in the catfish Pelteobagrus fulvidraco

Habitat fragmentation may have some significant effects on population genetic structure because geographic distance and physical barriers may impede gene flow between populations. In this study, we investigated whether recent habitat fragmentation affected genetic structure and diversity of populations of the nematode Procamallanus fulvidraconis in the yellowhead catfish, Pelteobagrus fulvidraco. The nematode was collected from 12 localities in 7 floodplain lakes of the Yangtze River. Using 11 intersimple sequence repeat markers, analysis of molecular variance showed that genetic diversity occurred mainly within populations (70.26%). Expected heterozygosity (He) of P. fulvidraconis was barely different between connected (0.2105) and unconnected lakes (0.2083). Population subdivision (Fst) between connected lakes (0.2177) was higher than in unconnected lakes (0.1676). However, the connected and unconnected lakes did not cluster into 2 clades. A Mantel test revealed significant positive correlation between genetic and geographic distances (R = 0.5335, P < 0.01). These results suggest that habitat fragmentation did not cause genetic differentiation among populations or a reduction of diversity in isolated populations of P. fulvidraconis. At least 2 factors may increase the dispersal range of the nematode, i.e., flash flooding in summer and other species of fish that may serve as the definitive hosts. Moreover, lake fragmentation is probably a recent process; population size of the nematode in these lakes is large enough to maintain population structure.     

Gene flow and genetic drift in urban environments

Evidence is growing that human modification of landscapes has dramatically altered evolutionary processes. In urban population genetic studies, urbanization is typically predicted to act as a barrier that isolates populations of species, leading to increased genetic drift within populations and reduced gene flow between populations. However, urbanization may also facilitate dispersal among populations, leading to higher genetic diversity within, and lower differentiation between, urban populations. We reviewed the literature on nonadaptive urban evolution to evaluate the support for each of these urban fragmentation and facilitation models. In a review of the literature with supporting quantitative analyses of 167 published urban population genetics studies, we found a weak signature of reduced within‐population genetic diversity and no evidence of consistently increased between‐population genetic differentiation associated with urbanization. In addition, we found that urban landscape features act as barriers or conduits to gene flow, depending on the species and city in question. Thus, we speculate that dispersal ability of species and environmental heterogeneity between cities contributes to the variation exhibited in our results. However, >90% of published studies reviewed here showed an association of urbanization with genetic drift or gene flow, highlighting the strong impact of urbanization on nonadaptive evolution. It is clear that species biology and city heterogeneity obscure patterns of genetic drift and gene flow in a quantitative analysis. Thus, we suggest that future research makes comparisons of multiple cities and nonurban habitats, and takes into consideration species' natural history, environmental variation, spatial modelling and marker selection.     

Spatial genetic patterns indicate mechanism and consequences of large carnivore cohabitation within development

Patterns of human development are shifting from concentrated housing toward sprawled housing intermixed with natural land cover, and wildlife species increasingly persist in close proximity to housing, roads, and other anthropogenic features. These associations can alter population dynamics and evolutionary trajectories. Large carnivores increasingly occupy urban peripheries, yet the ecological consequences for populations established entirely within urban and exurban landscapes are largely unknown. We applied a spatial and landscape genetics approach, using noninvasively collected genetic data, to identify differences in black bear spatial genetic patterns across a rural‐to‐urban gradient and quantify how development affects spatial genetic processes. We quantified differences in black bear dispersal, spatial genetic structure, and migration between differing levels of development within a population primarily occupying areas with >6 houses/km² in western Connecticut. Increased development disrupted spatial genetic structure, and we found an association between increased housing densities and longer dispersal. We also found evidence that roads limited gene flow among bears in more rural areas, yet had no effect among bears in more developed ones. These results suggest dispersal behavior is condition‐dependent and indicate the potential for landscapes intermixing development and natural land cover to facilitate shifts toward increased dispersal. These changes can affect patterns of range expansion and the phenotypic and genetic composition of surrounding populations. We found evidence that subpopulations occupying more developed landscapes may be sustained by male‐biased immigration, creating potentially detrimental demographic shifts.     

Fine-scale population differentiation and gene flow in a terrestrial salamander (Plethodon cinereus) living in continuous habitat

Several recent studies have shown that amphibian populations may exhibit high genetic subdivision in areas with recent fragmentation and urban development. Less is known about the potential for genetic differentiation in continuous habitats. We studied genetic differentiation of red-backed salamanders (Plethodon cinereus) across a 2-km transect through continuous forest in Virginia, USA. Mark-recapture studies suggest very little dispersal for this species, whereas homing experiments and post-Pleistocene range expansion both suggest greater dispersal abilities. We used six microsatellite loci to examine genetic population structure and differentiation between eight subpopulations of red-backed salamanders at distances from 200 m to 2 km. We also used several methods to extrapolate dispersal frequencies and test for sex-biased dispersal. We found small, but detectable differentiation among populations, even at distances as small as 200 m. Differentiation was closely correlated with distance and both Mantel tests and assignment tests were consistent with an isolation-by-distance model for the population. Extrapolations of intergenerational variance in spatial position (sigma(2)<15 m(2)) and pair-wise dispersal frequencies (4 Nm < 25 for plots separated by 300 m) both suggest limited gene flow. Additionally, tests for sex-biased dispersal imply that dispersal frequency is similarly low for both sexes. We suggest that these low levels of gene flow and the infrequent dispersal observed in mark-recapture studies may be reconciled with homing ability and range expansion if dispersing animals rarely succeed in breeding in saturated habitats, if dispersal is flexible depending on the availability of habitat, or if dispersal frequency varies across the geographic range of red-backed salamanders.     

Allozyme diversity and genetic structure of the leafy cactus (Pereskia guamacho [Cactaceae])

We examined levels of genetic variation and genetic structure in the leafy cactus (Pereskia guamacho) in arid and semiarid zones in Venezuela. We surveyed genetic diversity within 17 populations using 19 allozyme loci. Genetic diversity was relatively high at both the species (P(s) = 89%, A(s) = 3.26, AP(s) = 3.53, H(es) = 0.24) and population (P(p) = 63%, A(p) = 1.90, AP(p) = 2.42, H(ep) = 0.20) levels. A significant deficit of heterozygote individuals was detected within populations in the Paraguana Peninsula region (F(IS) = 0.301). Relatively low levels of population differentiation were detected at macrogeographic (G(ST) = 0.112) and regional levels (G(ST) = 0.044 for peninsula region and G(ST) = 0.074 for mainland region), suggesting substantial genetic exchange among populations; however, gene flow in this species seems to be regulated by the distance among populations. Overall, estimates of genetic diversity found in P. guamacho are concordant with the pattern observed for other cacti surveyed, namely high levels of polymorphism and genetic diversity with one common allele and several rare alleles per locus. Differences in gene dispersal systems between this species and other cacti studied were not reflected in the patterns of genetic diversity observed. The concentration of the highest estimates of genetic variation in northwestern Venezuela suggests a potential reservoir of plant genetic diversity within xerophilous ecosystems in northern South America.     

Genetic structure in a population of a tropical tree Ocotea tenera (Lauraceae): influence of avian seed dispersal

We studied the influence of avian seed dispersal on the structuring of genetic diversity in a population of a tropical tree, Ocotea tenera (Lauraceae). The seeds of O. tenera are principally dispersed by four, relatively specialized, fruit-eating bird species (emerald toucanets, keel-billed toucans, resplendent quetzals, and three-wattled bellbirds). We found high genetic diversity within the overall population and significant, nonrandom structuring of that diversity among subpopulations. Subpopulations contained members of several sibling groups, and most saplings within subpopulations were shown not to be the progeny of adult trees within the same subpopulation. Our data indicate that O. tenera subpopulations are founded with several seeds from few maternal families, and that this mode of establishment is an important determinant of population genetic architecture.     

Absence of isolation by distance patterns at the regional scale in the fungal plant pathogen Leptosphaeria maculans

Outcomes of host-pathogen coevolution are influenced by migration rates of the interacting species. Reduced gene flow with increasing spatial distance between populations leads to spatial genetic structure, as predicted by the isolation by distance (IBD) model. In wind-dispersed plant-pathogenic fungi, a significant spatial genetic structure is theoretically expected if local spore dispersal is more frequent than long-distance dispersal, but this remains to be documented by empirical data. For 29 populations of the oilseed rape fungus Leptosphaeria maculans sampled from two French regions, genetic structure was determined using eight minisatellite markers. Gene diversity (H = 0.62-0.70) and haplotypic richness (R = 0.96-1) were high in all populations. No linkage disequilibrium was detected between loci, suggesting the prevalence of panmictic sexual reproduction. Analysis of molecular variance showed that > 97% of genetic diversity was observed within populations. Genetic differentiation was low among populations (F(st) < 0.05). Although direct methods previously revealed short-distance dispersal for L. maculans, our findings of no correlation between genetic and geographic distances among populations illustrate that the IBD model does not account for dispersal of the fungus at the spatial scale we examined. These results indicate high gene flow among French populations of L. maculans, suggesting high dispersal rates and/or large effective population sizes, two characteristics giving the pathogen high evolutionary potential against the deployment of resistant oilseed rape cultivars.     

Population genetic structure of Venezuelan chiropterophilous columnar cacti (Cactaceae)

We conducted allozyme surveys of three Venezuelan self-incompatible chiropterophilous columnar cacti: two diploid species, Stenocereus griseus and Cereus repandus, and one tetraploid, Pilosocereus lanuginosus. The three cacti are pollinated by bats, and both bats and birds disperse seeds. Population sampling comprised two spatial scales: all Venezuelan arid zones (macrogeographic) and two arid regions in northwestern Venezuela (regional). Ten to 15 populations and 17-23 loci were analyzed per species. Estimates of genetic diversity were compared with those of other allozyme surveys in the Cactaceae to examine how bat-mediated gene dispersal affects the population genetic attributes of the three cacti. Genetic diversity was high for both diploid (P(s) = 94.1-100, P(p) = 56.7-72.3, H(s) = 0.182-0.242, H(p) = 0.161-0.205) and tetraploid (P(s) = 93.1, P(p) = 76.1, H(s) = 0.274, H(p) = 0.253) species. Within-population heterozygote deficit was detected in the three cacti at macrogeographic (F(IS) = 0.145-0.182) and regional (F(IS) = 0.057-0.174) levels. Low genetic differentiation was detected at both macrogeographic (G(ST) = 0.043-0.126) and regional (G(ST) = 0.009-0.061) levels for the three species, suggesting substantial gene flow among populations. Gene exchange among populations seems to be regulated by distance among populations. Our results support the hypothesis that bat-mediated gene dispersal confers high levels of genetic exchange among populations of the three columnar cacti, a process that enhances levels of genetic diversity within their populations.     

Social and genetic characteristics of geographically isolated populations in the ant Formica cinerea

The ant Formica cinerea in northern Europe has geographically isolated populations that were examined using five microsatellite loci. The populations differ widely regarding the social organization of colonies. Based on genetic relatedness (r) among worker nest mates, the populations were classified as M type with monogynous (single queen) colonies (r > 0.59), as P type with polygynous colonial networks (r < 0.1), or as intermediate with weakly polygynous colonies (0.16 < r < 0.47). The social types showed weak geographical clustering, but the overall distribution indicated that the shift between the social types has occurred several times. The geographically isolated populations had slightly reduced levels of genetic diversity compared to populations from areas where the species is abundant and continuously distributed. Many of the isolated populations consisted of monogynous or weakly polygynous colonies, making their effective population sizes small, and some of them also showed weak bottleneck effects. The overall level of microsatellite diversity within populations was relatively high and differentiation among populations low, indicating recent connections. Isolation of populations may thus be a new phenomenon resulting from reduction of suitable habitats. At the local level, we obtained limited support from a group of nearby subpopulations in southern Finland to the hypothesis that the P type is connected to restricted dispersal. Other P type populations did not, however, show similar elevated levels of differentiation.     

Fine scale population genetic structure of pumas in the Intermountain West

In this study, I examined the population genetic structure of subpopulations of pumas (Puma concolor) in Idaho and surrounding states. Patterns of genetic diversity, population structure, levels of inbreeding, and the relationship between genetic differentiation and dispersal distance within and between 15 subpopulations of pumas were compared. Spatial analyses revealed that the Snake River plain was an important barrier to movement between northern and southern regions of Idaho. In addition, subpopulations south of the Snake River plain exhibited lower levels of genetic diversity, higher levels of inbreeding, and a stronger pattern of isolation by distance relative to subpopulations north of the Snake River plain. Lower levels of diversity and restricted gene flow are likely the result of historically lower population sizes in conjunction with more recent changes in habitat use and available dispersal corridors for movement. The subdivision of puma populations north and south of the Snake River plain, along with the patterns of genetic diversity within regions, indicate that landscape features are affecting the population genetic structure of pumas in Idaho. These results indicate that information about the effects of landscape features on the distribution of genetic diversity should be considered when designing plans for the management and conservation of pumas.