Estimating Minimum Area of Suitable Habitat and Viable Population Size for the Northern Muriqui (Brachyteles hypoxanthus)

A population viability analysis (PVA) using the computer package VORTEX was conducted to assess the minimum viable population (MVP) of the Atlantic Forest endemic primate Brachyteles hypoxanthus. The objectives were: (1) to estimate demographic and genetic MVPs that could be used as quasi-extinction thresholds for future modeling, and (2) to estimate the minimum area of suitable habitat (MASH). The model predicted that populations of 40 and 700 individuals were necessary to achieve demographic and genetic stability, respectively. The model was more sensitive to changes in inbreeding depression, sex ratio and reproduction (percentage of breeding females). MASH estimated to contain genetically viable populations reached 11,570 ha. Muriquis have managed to persist despite severe habitat disturbance, but the results suggest that although most of the extant populations are not threatened by extinction, they are too small to be genetically viable in the long-run, and will loose most of their heterozygosity.     

Effectiveness of a reserve network for the conservation of the endemic marsupial Micoureus travassosi in Atlantic Forest remnants in southeastern Brazil

Habitat loss and fragmentation are serious threats to biodiversity conservation in the Atlantic Forest. A network of protected reserves is essential to the protection of native fauna and flora. However, internal and external factors may threaten the preservation of biota, thus population viability analyses (PVA) are important tools in reserve design and management planning. A PVA was carried out, using the computer package VORTEX, to assess the effectiveness of the reserve network of Rio de Janeiro State in Brazil in retaining viable populations of the endemic marsupial Micoureus travassosi. The PVA takes into account demographic, genetic and environmental stochastic events and catastrophes (fire). Rio de Janeiro state has 31 reserves, and 20 of those were considered to retain viable populations for 100 years, whereas eight were predicted to suffer from genetic decay, two from both genetic decay and demographic stochasticity, and one of them probably has an extinct population. The minimum area of suitable habitat needed to maintain a minimum viable population of M. travassosi is estimated at 3600ha. Sensitivity analysis was run for mortality, sex ratio, percentage of reproductive females, inbreeding depression and probability of catastrophes, and suggests that inbreeding depression is important in small population sizes, whereas the effects of catastrophes were significant only for large populations. Although the model indicates that some populations will suffer from demographic and/or genetic stochasticity, the reserve network of Rio de Janeiro state will likely keep M. travassosi's populations for the next 100 years.     

Comparison of genetic population structure of the large blue butterflies Maculinea nausithous and M. teleius

We investigated the genetic population structure of two rare myrmecophilous lycaenid butterflies, Maculinea nausithous and M. teleius, which often live sympatrically and have similar biology. In Europe, both species occur in highly fragmented populations and are vulnerable to local extinction. The proportion of variable allozyme loci, average heterozygosity and genetic differentiation among populations was higher in M. nausithous than in sympatrically living M. teleius populations. We hypothesise that the differences in heterozygosity are mainly due to the known higher efficiency of typical host ant nests in rearing M. nausithous pupae compared to M. teleius pupae. This implies a larger probability of larval survival in M. nausithous, which buffers populations against environmental and demographic stochasticity. In contrast, the lower carrying capacity of ant nests in rearing M. teleius pupae requires higher nest-densities and makes M. teleius populations more prone to losing genetic variation through drift if this condition is not fulfilled. The single investigated Russian population of M. teleius showed much higher levels of heterozygosity than any of the Polish populations, suggesting a more viable and still intact metapopulation structure.     

Importance of demography and dispersal for the resilience and restoration of a critically endangered tropical conifer Araucaria nemorosa

Aims In situ species survival involves persistence at current sites and/or colonization of new locations. Determining the likelihood of these events requires an understanding of population dynamics and dispersal. We address these issues in populations of a critically endangered tropical conifer Araucaria nemorosa and provide conservation recommendations. Location Port Boise, island of Grand Terre, New Caledonia, Pacific Ocean. Methods We characterize the demographic structure of six populations of A. nemorosa based upon size class frequencies and relative basal area compared to competing angiosperm trees. Using genotype data from 280 adult individuals at seven microsatellite loci, we indirectly estimate dispersal distances and project a maximal dispersal envelope around the extant populations. Results Our survey detected marked differences in demographic parameters including the proportion of basal area occupied by A. nemorosa versus angiosperm trees (ranging from 25% to 77%), the size class frequency distributions of A. nemorosa and seedling densities (ranging from 500 to 37300 seedlings ha^?1) among some populations. Wright’s genetic neighbourhood ranged from 22 to 876 trees, and historic gene dispersal ranged from 10.8 to 82.4 m, indicating that most seed dispersal is <100 m. Main conclusions This study indicates that the risk of recruitment failure in remnant populations of Araucaria nemorosa is low in most of the stands but is high in the inland population Forêt Nord. In situ natural regeneration appears to be constrained in this population, most likely as a consequence of competitive exclusion. Our results also suggest that the majority of seed dispersal is too short to allow A. nemorosa to disperse to new more hospitable sites within an ecologically relevant time‐scale. Our findings have implications not only for this emblematic tree species but also for a wide range of fragmented and degraded plant species populations with limited dispersal that are vulnerable to competitive exclusion.     

Seascape genetics of the stalked kelp Pterygophora californica and comparative population genetics in the Santa Barbara Channel

We conducted a population genetic analysis of the stalked kelp, Pterygophora californica, in the Santa Barbara Channel, California, USA. The results were compared with previous work on the genetic differentiation of giant kelp, Macrocystis pyrifera, in the same region. These two sympatric kelps not only share many life history and dispersal characteristics but also differ in that dislodged P. californica does not produce floating rafts with buoyant fertile sporophytes, commonly observed for M. pyrifera. We used a comparative population genetic approach with these two species to test the hypothesis that the ability to produce floating rafts increases the genetic connectivity among kelp patches in the Santa Barbara Channel. We quantified the association of habitat continuity and oceanographic distance with the genetic differentiation observed in stalked kelp, like previously conducted for giant kelp. We compared both overall (across all patches) and pairwise (between patches) genetic differentiation. We found that oceanographic transit time, habitat continuity, and geographic distance were all associated with genetic connectivity in P. californica, supporting similar previous findings for M. pyrifera. Controlling for differences in heterozygosity between kelp species using Jost's D_EST, we showed that global differentiation and pairwise differentiation were similar among patches between the two kelp species, indicating that they have similar dispersal capabilities despite their differences in rafting ability. These results suggest that rafting sporophytes do not play a significant role in effective dispersal of M. pyrifera at ecologically relevant spatial and temporal scales.     

Combining demography and genetic analysis to assess the population structure of an amphibian in a human-dominated landscape

In this article, we applied demographic and genetic approaches to assess how landscape features influence dispersal patterns and genetic structure of the common frog Rana temporaria in a landscape where anthropogenic perturbations are pervasive (urbanization and roads). We used a combination of GIS methods that integrate radiotracking and landscape configuration data, and simulation techniques in order to estimate the potential dispersal area around breeding patches. Additionally, genetic data provided indirect measures of dispersal and allowed to characterise the spatial genetic structure of ponds and the patterns of gene flow across the landscape. Although demographic simulations predicted six distinct groups of habitat patches within which movement can occur, genetic analyses suggested a different configuration. More precisely, BAPS5 spatial clustering method with ponds as the analysis unit detected five spatial clusters. Individual-based analyses were not able to detect significant genetic structure. We argue that (1) taking into account that each individual breeds in specific breeding patch allowed for better explanation of population functioning, (2) the discrepancy between direct (radiotracking) and indirect (genetic) estimates of subpopulations (breeding patches) is due to a recent landscape fragmentation (e.g. traffic increase). We discuss the future of this population in the face of increasing landscape fragmentation, focusing on the need for combining demographic and genetic approaches when evaluating the conservation status of population subjected to rapid landscape changes.     

Metapopulation genetic structure of two coexisting parasitoids of the Glanville fritillary butterfly

We investigated the metapopulation genetic structure of two specialist parasitoids, Cotesia melitaearum and Hyposoter horticola, attacking the Glanville fritillary butterfly (Melitaea cinxia) in the Åland Islands south-western Finland. The host butterfly persists as a classic metapopulation in a network of 4,000 small habitat patches within an area of 50 by 70 km . The two parasitoids are known to differ greatly in their population dynamics and spatial pattern of occupancy in local host populations. Analysis of genetic population structure using F_ST and clustering of multilocus genotypes revealed a distinct large-scale spatial structure in C. melitaearum but a very weak pattern in H. horticola. This result is consistent with the known difference in the dispersal range (much longer in H. horticola) and population size (much greater in H. horticola) of the two parasitoids.     

Spatial graphs highlight how multi-generational dispersal shapes landscape genetic patterns

Current approaches that compare spatial genetic structure of a given species and the dispersal of its mobile phase can detect a mismatch between both patterns mainly due to processes acting at different temporal scales. Genetic structure result from gene flow and other evolutionary and demographic processes over many generations, while dispersal predicted from the mobile phase often represents solely one generation on a single time-step. In this study, we present a spatial graph approach to landscape genetics that extends connectivity networks with a stepping-stone model to represent dispersal between suitable habitat patches over multiple generations. We illustrate the approach with the case of the striped red mullet Mullus surmuletus in the Mediterranean Sea. The genetic connectivity of M. surmuletus was not correlate with the estimated dispersal probability over one generation, but with the stepping-stone estimate of larval dispersal, revealing the temporal scale of connectivity across the Mediterranean Sea. Our results highlight the importance of considering multiple generations and different time scales when relating demographic and genetic connectivity. The spatial graph of genetic distances further untangles intra-population genetic structure revealing the Siculo-Tunisian Strait as an important corridor rather than a barrier for gene flow between the Western- and Eastern Mediterranean basins, and identifying Mediterranean islands as important stepping-stones for gene flow between continental populations. Our approach can be easily extended to other systems and environments.     

Measures of gene flow in the Columbian ground squirrel

From analyses of published data and a review of the literature, I studied indirect and direct measures of gene flow among populations of Columbian ground squirrels, Spermophilus columbianus. New analyses were used to examine an allozyme data set (seven polymorphic loci) that had been collected by Zammuto and Millar (1985a) from six populations of ground squirrels that were spread over 183 km. G-tests indicated significant variation in allele frequencies among populations, but F-statistics revealed relatively little population differentiation (average F _ST=0.026). F _ST values were used to estimate rates of gene flow indirectly and indicated fairly high rates of gene flow (average N _e m=13.5). Recorded dispersal distances of individual ground squirrels were fairly short (most<4 km, maximum recorded distance was 8.5 km), and the minimum distance between populations used to create the allozyme data set was about 25 km. Thus, direct dispersal among the populations in the allozyme data set was highly unlikely. Small genetically effective populations may have experienced high rates of migration over short distances (about 43% of adults in local populations were immigrants), however, resulting in homogeneous allele frequencies over the geographic range. This explanation provides an alternative to invoking gene flow in the recent past to explain discrepancies between dispersal distances in the field and homogenization of allele frequencies over large ranges, Mammalian species that have virtually complete dispersal of subadult males from the natal area might be expected to exhibit relatively high rates of gene flow, regardless of actual dispersal distances. Genetically effective populations may be much smaller than more extensive ecological populations and experience higher rates of gene flow.     

DIRECT AND INDIRECT ESTIMATES OF NEIGHBORHOOD AND EFFECTIVE POPULATION SIZE IN A TROPICAL PALM,ASTROCARYUM MEXICANUM

To estimate the relative importance of genetic drift, the effective population size ???(N_e) can be used. Here we present estimates of the effective population size and related measures in Astrocaryum mexicanum, a tropical palm from Los Tuxtlas rain forest, Veracruz, Mexico. Seed and pollen dispersal were measured. Seeds are primarily dispersed by gravity and secondarily dispersed by small mammals. Mean primary and secondary dispersal distances for seeds were found to be small (0.78 m and 2.35 m, respectively). A. mexicanum is beetle pollinated and pollen movements were measured by different methods: a) using fluorescent dyes, b) as the minimum distance between active female and male inflorescences, and c) using rare allozyme alleles as genetic markers. All three estimates of pollen dispersal were similar, with a mean of approximately 20 m. Using the seed and pollen dispersal data, the genetic neighborhood area (A) was estimated to be 2,551 m². To obtain the effective population size, three different overlapping generation methods were used to estimate an effective density with demographic data from six permanent plots. The effective density ranged from 0.040 to 0.351 individuals per m². The product of effective density and neighborhood area yields a direct estimate of the neighborhood effective population size (N_b). N_b ranged from 102 to 895 individuals. Indirect estimates of population size and migration rate (Nm) were obtained using F_st for five different allozymic loci for both adults and seeds. We obtained a range of Nm from 1.2 to 19.7 in adults and a range of Nm from 4.0 to 82.6 for seeds. We discuss possible causes of the smaller indirect estimates of Nm relative to the direct and compare our estimates with values from other plant populations. Gene dispersal distances, neighborhood size, and effective population size in A. mexicanum are relatively high, suggesting that natural selection, rather than genetic drift, may play a dominant role in patterning the genetic variation in this tropical palm.     

Demographic consequences of population subdivision on the long-furred woolly mouse opossum (Micoureus paraguayanus) from the Atlantic Forest

Habitat destruction and fragmentation severely affected the Atlantic Forest. Formerly contiguous populations may become subdivided into a larger number of smaller populations, threatening their long-term persistence. The computer package VORTEX was used to simulate the consequences of habitat fragmentation and population subdivision on Micoureus paraguayanus, an endemic arboreal marsupial of the Atlantic Forest. Scenarios simulated hypothetical populations of 100 and 2000 animals being partitioned into 1–10 populations, linked by varying rates of inter-patch dispersal, and also evaluated male-biased dispersal. Results demonstrated that a single population was more stable than an ensemble of populations of equal size, irrespective of dispersal rate. Small populations (10–20 individuals) exhibited high instability due to demographic stochasticity, and were characterized by high rates of extinction, smaller values for metapopulation growth and larger fluctuations in population size and growth rate. Dispersal effects on metapopulation persistence were related to the size of the populations and to the sexes that were capable of dispersing. Male-biased dispersal had no noticeable effects on metapopulation extinction dynamics, whereas scenarios modelling dispersal by both sexes positively affected metapopulation dynamics through higher growth rates, smaller fluctuations in growth rate, larger final metapopulation sizes and lower probabilities of extinction. The present study highlights the complex relationships between metapopulation size, population subdivision, habitat fragmentation, rate of inter-patch dispersal and sex-biased dispersal and indicates the importance of gaining a better understanding of dispersal and its interactions with correlations between disturbance events.     

A genetic demographic analysis of Lake Malawi rock‐dwelling cichlids using spatio‐temporal sampling

We estimated the effective population sizes (N_e) and tested for short‐term temporal demographic stability of populations of two Lake Malawi cichlids: Maylandia benetos, a micro‐endemic, and Maylandia zebra, a widespread species found across the lake. We sampled a total of 351 individuals, genotyped them at 13 microsatellite loci and sequenced their mitochondrial D‐loop to estimate genetic diversity, population structure, demographic history and effective population sizes. At the microsatellite loci, genetic diversity was high in all populations. Yet, genetic diversity was relatively low for the sequence data. Microsatellites yielded mean N_e estimates of 481 individuals (±99 SD) for M. benetos and between 597 (±106.3 SD) and 1524 (±483.9 SD) individuals for local populations of M. zebra. The microsatellite data indicated no deviations from mutation–drift equilibrium. Maylandia zebra was further found to be in migration–drift equilibrium. Temporal fluctuations in allele frequencies were limited across the sampling period for both species. Bayesian Skyline analyses suggested a recent expansion of M. zebra populations in line with lake‐level fluctuations, whereas the demographic history of M. benetos could only be estimated for the very recent past. Divergence time estimates placed the origin of M. benetos within the last 100 ka after the refilling of the lake and suggested that it split off the sympatric M. zebra population. Overall, our data indicate that micro‐endemics and populations in less favourable habitats have smaller N_e, indicating that drift may play an important role driving their divergence. Yet, despite small population sizes, high genetic variation can be maintained.     

Host habitat patchiness and the distance decay of similarity among gastro-intestinal nematode communities in two species of <Emphasis Type="Italic">Mastomys</Emphasis> (southeastern Senegal)

Beta-diversity, or how species composition changes with geographical distance, has seldom been studied for different habitats. We present here quantitative estimates of the relationship between geographic distance and similarity of parasitic nematode communities in two closely related rodent host species that live in habitats with very different spatial configurations. In southeastern Senegal Mastomys natalensis lives exclusively inside human villages whereas M. erythroleucus is continuously distributed outside villages. Both host species and their gastro-intestinal nematodes were sampled on the same spatial scale. Beta-diversity was found to be higher in parasite communities of M. erythroleucus than in those of M. natalensis, and significantly related to geographic distance in this first species. Even on the local spatial scale studied, host dispersal limitation, and stochastic events, may affect species turnover in nematode communities of M. erythroleucus. In M. natalensis, no relationship was found between geographic distance and nematode community similarity, however, suggesting low host dispersal rates between habitat patches. Together with previous population genetic results, this study illustrates the need for different approaches with regard to dispersal in natural populations and its effect on biodiversity.     

Microsatellite variation in simulated and natural founder populations of the Laysan finch (Telespiza cantans)

Historical and demographic data were used in a computer model tosimulate neutral genetic change in populations of the Laysanfinch (Telespiza cantans), an insular passerine bird that hasundergone documented founder events at Pearl and Hermes reef(PHR). Measures of genetic variation in the natural PHRpopulations generally matched those in the simulated populations,except that heterozygosity on Southeast Island was lower than themodel predicted, and the heterozygote excess in the naturalpopulations had a low probability of occurrence in the simulatedpopulations. The estimate of effective population size (N _e) fromthe stochastic demographic model matched the estimate fromgenetic data for two populations, but the demographic estimatewas higher than the genetic estimate for Southeast Island. Smallfounder number was rejected as a possible explanation for thereduced genetic variation on Southeast. We suggest that N _e wasoverestimated in part because we assumed seasonal variance inreproductive success. Additional variance components need to bemeasured in the field and incorporated into the model. Accounting for the heterozygote excess also requires furthertheoretical and field investigations. Possible explanations forthe excess include inbreeding depression, incest avoidance, andthe effect of polygyny on heterozygote excess in smallpopulations. We concluded that the Pearl and Hermes reefpopulation will continue to lose genetic variation at a highrate, and translocations from the native population on Laysan maybe required to maintain a viable population on the reef.     

Is the Atlantic Forest protected area network efficient in maintaining viable populations of Brachyteles hypoxanthus?

Habitat loss and fragmentation are serious threats to biodiversity conservation in the Atlantic Forest. A network of protected areas is essential to the protection of native biodiversity. However, internal and external factors may threaten the preservation of biota, thus population viability analyses (PVA) are important tools in protected area design and management planning. A PVA was carried out, using the computer package VORTEX, to assess the effectiveness of the protected area network within the Atlantic Forest in Brazil in retaining viable populations of the endemic primate Brachyteles hypoxanthus. The Brazilian Atlantic Forest has 42 protected areas within B. hypoxanthus geographic distribution area, and only five of those were considered to retain viable populations for 50 generations, whereas 28 were predicted to suffer from genetic decay, seven from both genetic decay and demographic stochasticity, and two of them are probably extinct populations. The model indicates that although the protected area network of the Atlantic Forest will likely keep B. hypoxanthus populations for the next 50 generations, most of them (35 out of 42, or 83%) will be facing some kind of demographic and/or genetic problem and will probably need management actions to be implemented in order to ensure their persistence.     

A phylogeographic study of the stoneplant Conophytum (Aizoaceae; Ruschioideae; Ruschieae) in the Bushmanland Inselberg Region (South Africa) suggests anemochory

The Bushmanland Inselberg Region (BIR) of South Africa provides an ideal system to study population interactions, as these inselbergs function as islands of Succulent Karoo surrounded by Nama Karoo vegetation. The population genetics of four Conophytum taxa endemic to the quartz-associated habitats of inselbergs in the BIR were investigated using amplified fragment length polymorphisms (AFLP), namely C. marginatum subsp. haramoepense, C. marginatum subsp. marginatum, C. maughanii, and C. ratum. Conophytum marginatum colonizes the quartz outcrops on the summits of the inselbergs, while C. maughanii and C. ratum occupy quartz patches at the summit and base of the inselbergs. A total of 24 populations were sampled to assess genetic differentiation between populations of each species, specifically between summit and base populations of C. ratum, eastern and western populations of C. maughanii and populations of the two subspecies of C. marginatum. Moderate levels of genetic differentiation were recovered between the summit and base populations of C. ratum, with an indication of some genetic connectivity between the populations. Slight differentiation between the eastern and western populations of C. maughanii was recovered, however, this was not reflected in the PCoA and STRUCTURE results. In C. marginatum, no significant genetic differentiation was recovered between populations of the subspecies. These results may reflect evidence of different dispersal mechanisms in the species, with the genetic connectivity between populations of C. ratum possibly indicating dispersal through hygrochastic capsules, while genetic connectivity between populations of C. maughanii and C. marginatum may, for the first time, suggest long-distance dispersal, i.e. anemochory. This study provides the first insights into population interactions across the BIR and highlights the importance of conservation in the region, particularly of the Gamsberg, in light of the recent mining activities.     

Congruent population structure inferred from dispersal behaviour and intensive genetic surveys of the threatened Florida scrub-jay (Aphelocoma coerulescens)

The delimitation of populations, defined as groups of individuals linked by gene flow, is possible by the analysis of genetic markers and also by spatial models based on dispersal probabilities across a landscape. We combined these two complimentary methods to define the spatial pattern of genetic structure among remaining populations of the threatened Florida scrub-jay, a species for which dispersal ability is unusually well-characterized. The range-wide population was intensively censused in the 1990s, and a metapopulation model defined population boundaries based on predicted dispersal-mediated demographic connectivity. We subjected genotypes from more than 1000 individual jays screened at 20 microsatellite loci to two Bayesian clustering methods. We describe a consensus method for identifying common features across many replicated clustering runs. Ten genetically differentiated groups exist across the present-day range of the Florida scrub-jay. These groups are largely consistent with the dispersal-defined metapopulations, which assume very limited dispersal ability. Some genetic groups comprise more than one metapopulation, likely because these genetically similar metapopulations were sundered only recently by habitat alteration. The combined reconstructions of population structure based on genetics and dispersal-mediated demographic connectivity provide a robust depiction of the current genetic and demographic organization of this species, reflecting past and present levels of dispersal among occupied habitat patches. The differentiation of populations into 10 genetic groups adds urgency to management efforts aimed at preserving what remains of genetic variation in this dwindling species, by maintaining viable populations of all genetically differentiated and geographically isolated populations.     

Population genetic structure of Bellamya aeruginosa (Mollusca: Gastropoda: Viviparidae) in China: weak divergence across large geographic distances

Bellamya aeruginosa is a widely distributed Chinese freshwater snail that is heavily harvested, and its natural habitats are under severe threat due to fragmentation and loss. We were interested whether the large geographic distances between populations and habitat fragmentation have led to population differentiation and reduced genetic diversity in the species. To estimate the genetic diversity and population structure of B. aeruginosa, 277 individuals from 12 populations throughout its distribution range across China were sampled: two populations were sampled from the Yellow River system, eight populations from the Yangtze River system, and two populations from isolated plateau lakes. We used seven microsatellite loci and mitochondrial cytochrome oxidase I sequences to estimate population genetic parameters and test for demographic fluctuations. Our results showed that (1) the genetic diversity of B. aeruginosa was high for both markers in most of the studied populations and effective population sizes appear to be large, (2) only very low and mostly nonsignificant levels of genetic differentiation existed among the 12 populations, gene flow was generally high, and (3) relatively weak geographic structure was detected despite large geographic distances between populations. Further, no isolation by linear or stream distance was found among populations within the Yangtze River system and no signs of population bottlenecks were detected. Gene flow occurred even between far distant populations, possibly as a result of passive dispersal during flooding events, zoochoric dispersal, and/or anthropogenic translocations explaining the lack of stronger differentiation across large geographic distances. The high genetic diversity of B. aeruginosa and the weak population differentiation are likely the results of strong gene flow facilitated by passive dispersal and large population sizes suggesting that the species currently is not of conservation concern.     

The genetic underpinnings of population cyclicity: establishing expectations for the genetic anatomy of cycling populations

Despite extensive research into the mechanisms underlying population cyclicity, we have little understanding of the impacts of numerical fluctuations on the genetic variation of cycling populations. Thus, the potential implications of natural and anthropogenically‐driven variation in population cycle dynamics on the diversity and evolutionary potential of cyclic populations is unclear. Here, we use Canada lynx Lynx canadensis matrix population models, set up in a linear stepping‐stone, to generate demographic replicates of biologically realistic cycling populations. Overall, increasing cycle amplitude predictably reduced genetic diversity and increased genetic differentiation, with cyclic effects increased by population synchrony. Modest dispersal rates (1–3% of the population) between high and low amplitude cyclic populations did not diminish these effects suggesting that spatial variation in cyclic amplitude should be reflected in patterns of genetic diversity and differentiation at these rates. At high dispersal rates (6%) groups containing only high amplitude cyclic populations had higher diversity and lower differentiation than those mixed with low amplitude cyclic populations. Negative density‐dependent dispersal did not impact genetic diversity, but did homogenize populations by reducing differentiation and patterns of isolation by distance. Surprisingly, temporal changes in diversity and differentiation throughout a cycle were not always consistent with population size. In particular, negative density‐dependent dispersal simultaneously decreased differences in genetic diversity while increasing differences in genetic differentiation between numerical peaks and nadirs. Combined, our findings suggest demographic changes at fine temporal scales can impact genetic variation of interacting populations and provide testable predictions relating population cyclicty to genetic variation. Further, our results suggest that including realistic demographic and dispersal parameters in population genetic models and using information from temporal changes in genetic variation could help to discern complex demographic scenarios and illuminate population dynamics at fine temporal scales.