Differences In Population Dynamics Research Articles

Exploring patterns of female house mouse spatial organisation among outbreaking and stable populations.

The size and distribution of home ranges reflect how individuals within a population use, defend, and share space and resources, and may thus be an important predictor of population-level dynamics. Eruptive species, such as the house mouse in Australian grain-growing regions, are an ideal species in which to investigate variations in space use and home range overlap between stable and outbreaking populations. In this study, we use spatially explicit capture-recapture models to explore if space use and home range overlap among female mice could serve as indicators of changes in population density leading into summer. Additionally, we assess the sensitivity of space use and home range estimates to reduced recapture rates. Our analysis did not reveal variations in the spring spatial organisation of female mice based on existing capture-mark-recapture data. However, our study highlights the need to balance monitoring efforts within regions, emphasising the importance of exploring studies that can improve spatial recaptures by optimising trapping efforts. This is particularly important in Australian agricultural systems, where varying farm management practices may drive differences in population dynamics.

Understanding the impact of population dynamics on water use utilizing multi-source big data

Abstract Population movement, such as commuting, can affect water supply pressure and efficiency in modern cities. However, there is a gap in the research concerning the relationship between water use and population mobility, which is of great significance for urban sustainable development. In this study, we analyzed the spatial–temporal dynamics of the population and its underlying mechanisms, using multi-source geospatial big data, including Baidu heat maps (BHMs), land use parcels, and point of interest. Combined with water consumption, sewage volume, and river depth data, the impact of population dynamics on water use was investigated. The results showed that there were obvious differences in population dynamics between weekdays and weekends with a ratio of 1.11 for the total population. Spatially, the population concentration was mainly observed in areas associated with enterprises, industries, shopping, and leisure activities during the daytime, while at nighttime, it primarily centered around residential areas. Moreover, the population showed a significant impact on water use, resulting in co-periods of 24 h and 7 days, and the water consumption as well as the wastewater production were observed to be proportional to the population density. This study can offer valuable implications for urban water resource allocation strategies.

Seasonal specialization drives divergent population dynamics in two closely related butterflies

Seasons impose different selection pressures on organisms through contrasting environmental conditions. How such seasonal evolutionary conflict is resolved in organisms whose lives span across seasons remains underexplored. Through field experiments, laboratory work, and citizen science data analyses, we investigate this question using two closely related butterflies (Pieris rapae and P. napi). Superficially, the two butterflies appear highly ecologically similar. Yet, the citizen science data reveal that their fitness is partitioned differently across seasons. Pieris rapae have higher population growth during the summer season but lower overwintering success than do P. napi. We show that these differences correspond to the physiology and behavior of the butterflies. Pieris rapae outperform P. napi at high temperatures in several growth season traits, reflected in microclimate choice by ovipositing wild females. Instead, P. rapae have higher winter mortality than do P. napi. We conclude that the difference in population dynamics between the two butterflies is driven by seasonal specialization, manifested as strategies that maximize gains during growth seasons and minimize harm during adverse seasons, respectively.

Life History of Chrysodeixis includens (Lepidoptera: Noctuidae) on Positively Charged Zein Nanoparticles.

Research indicates that nanoparticles can be an effective agricultural pest management tool, though unintended effects on the insect must be evaluated before their use in agroecosystems. Chrysodeixis includens (Walker) was used as a model to evaluate chronic parental and generational exposure to empty, positively charged zein nanoparticles ((+)ZNP) and methoxyfenozide-loaded zein nanoparticles (+)ZNP(MFZ) at low-lethal concentrations. To determine concentration limits, an acute toxic response test on meridic diet evaluated (+)ZNP(MFZ) and technical grade methoxyfenozide using two diet assay techniques. No differences in acute toxicity were observed between the two treatments within their respective bioassays. With these results, population dynamics following chronic exposure to low-lethal concentrations were evaluated. Parental lifetables evaluated cohorts of C. includens reared on diet treated with LC5 equivalents of (+)ZNP, (+)ZNP(MFZ), or technical grade methoxyfenozide. Compared to technical grade methoxyfenozide, (+)ZNP(MFZ) lowered both the net reproductive rate and intrinsic rate of increase, and was more deleterious to C. includens throughout its lifespan. This was contrasted to (+)ZNP, which showed no differences in population dynamics when compared with the control. To evaluate chronic exposure to (+)ZNP, generational lifetables reared cohorts of C. includens on LC5 equivalent values of (+)ZNP and then took the resulting offspring to be reared on either (+)ZNP or untreated diet. No differences in lifetable statistics were observed between the two treatments, suggesting that (+)ZNP at low ppm do not induce toxic generational effects. This study provides evidence into the effects of nanodelivered methoxyfenozide and the generational impact of (+)ZNP.

Mountain biogeography coming full circle: a new '3D' floristic approach provides units for reconstructing evolutionary trajectories.

This article is a Commentary on Li et al. (2021), 232: 1424–1435.

Динамика численности населения Волгоградской, Самарской и Саратовской областей: вклад миграции

Volgograd, Samara and Saratov regions are neighboring regions. Demographic development in the regions has general trends. Migration is becoming the main component influencing the differences in population dynamics in the regions. The Samara region continues to attract both interregional Russian and international migrants.

Stage‐structured ontogeny in resource populations generates non‐additive stabilizing and de‐stabilizing forces in populations and communities

Demographic heterogeneity influences how populations respond to density dependent intraspecific competition and trophic interactions. Distinct stages across an organism's development, or ontogeny, are an important example of demographic heterogeneity. In consumer populations, ontogenetic stage structure has been shown to produce categorical differences in population dynamics, community dynamics and even species coexistence compared to models lacking explicit ontogeny. The study of consumer–resource interactions must also consider the ontogenetic stage structure of the resource itself, particularly plants, given their fundamental role at the basis of terrestrial food webs. We incorporate distinct ontogenetic stages of plants into an adaptable multi‐stage consumer–resource modeling framework that facilitates studying how stage specific consumers shape trophic dynamics at low trophic levels. We describe the role of density dependent demographic rates in mediating the dynamics of stage‐structured plant populations. We then investigate how these demographic rates interact with consumer pressure to influence stability and coexistence in multiple stage‐specific consumer–resource interactions. Results detail how density dependent effects across distinct ontogenetic stages in plant development produce non‐additivity in the drivers of dynamic stability both in single populations and in consumer–resource settings, challenging the ubiquity of certain traditional ecological dynamic paradigms. We also find categorical differences in the population variability induced by herbivores consuming separate plant stages. Consumer–resource models, such as plant–herbivore interactions, often average out demographic heterogeneity in populations. Here, we show that explicitly including plant demographic heterogeneity through ontogeny yields distinct dynamic expectations for both plants and herbivores compared to traditional consumer–resource formulations. Our results indicate that efforts to understand the demographic effect of herbivores on plant populations may need to also consider the effects of plant demographics on herbivores and the reciprocal relationship between them.

Growth–reproduction trade‐off and fecundity regulate population stability in Amazon floodplain fishes

Abstract Understanding the factors that regulate temporal changes in population size is a core aspiration in ecology given the importance of population stability on the maintenance of species interactions, effects on local communities, the stability of ecosystems, and for biodiversity conservation. Understanding temporal trends in population size can support management practices as this may indicate demographic resilience for exploited species. Theoretical studies have long suggested that life‐history traits regulate population stability, but empirical support remains limited, especially for species‐rich environments. Additionally, harvesting has been suggested as an important factor increasing the fluctuation in the number of individuals in populations. In this study, we analysed population stability of 70 Amazonian floodplain fish species in relation to life‐history traits and the degree of fishing pressure. Our data covered a long time scale and broad geographical range of the Amazon floodplain. For that, we compiled datasets of two monitoring programmes, one comprising data from a single lake for 15 years and a second dataset with information from three floodplain lakes sampled over 5 years. The resulting geographical range spanned one of the most fished areas in the upper Amazon River, between the municipalities of Coari and Manaus, in the Brazilian Amazon. Temporal stability was measured as the coefficient of variation in species abundance. Population life‐history traits and the degree of fishing pressure were estimated at the species level. Population temporal stability had significant relationships with three life‐history traits: maximum body size, fecundity, somatic investment before sexual maturation (SIBSM), and the interaction of fecundity and SIBSM. Species with small body size, high fecundity, and low SIBSM displayed low stability; the opposite happened to species that invest highly in somatic tissue before the first reproduction and have large body size. Fishing pressure had no significant contribution to explaining population stability. However, the sampling technique employed and the set of species considered in the study do not represent main targets of fisheries. Here we stress the importance of life‐history traits in controlling an essential part of the population size variation in a complex and species‐rich fish assemblage in the Amazon floodplains. Our results highlight the importance of the trade‐off between growth and reproduction in controlling population stability and complement explanations on how life‐history functional traits underlie differences in population dynamics over time. Our results contribute to theoretical development and can be used to support fisheries and biological conservation management strategies. Specifically, our results point to the possibility of inferring demographic resilience based on life‐history information in the absence of high‐quality population data.

Sex Differences in Population Dynamics during Formation of Kidney Bacterial Communities by Uropathogenic Escherichia coli.

Uropathogenic Escherichia coli (UPEC), the primary etiologic agent of urinary tract infections (UTIs), encounters a restrictive population bottleneck within the female mammalian bladder. Its genetic diversity is restricted during establishment of cystitis because successful UPEC must invade superficial bladder epithelial cells prior to forming clonal intracellular bacterial communities (IBCs). In this study, we aimed to understand UPEC population dynamics during ascending pyelonephritis, namely, formation of kidney bacterial communities (KBCs) in the renal tubular lumen and nucleation of renal abscesses. We inoculated the bladders of both male and female C3H/HeN mice, a background which features vesicoureteral reflux; we have previously shown that in this model, males develop severe, high-titer pyelonephritis and renal abscesses much more frequently than females. Mice were infected with 40 isogenic, PCR-tagged ("barcoded") UPEC strains, and tags remaining in bladder and kidneys were ascertained at intervals following infection. In contrast to females, males maintained a majority of strains within both the bladder and kidneys throughout the course of infection, indicating only a modest host-imposed bottleneck on overall population diversity during successful renal infection. Moreover, the diverse population in the infected male kidneys obscured any restrictive bottleneck in the male bladder. Finally, using RNA in situ hybridization following mixed infections with isogenic UPEC bearing distinct markers, we found that despite their extracellular location (in the urinary space), KBCs are clonal in origin. This finding indicates that even with bulk reflux of infected bladder urine into the renal pelvis, successful ascension of UPEC to establish the tubular niche is an uncommon event.

Population responses to observed climate variability across multiple organismal groups

A major challenge in ecology is to understand how populations are affected by increased climate variability. Here, we assessed the effects of observed climate variability on different organismal groups (amphibians, insects, mammals, herbaceous plants and reptiles) by estimating the extent to which interannual variation in the annual population growth rates (CVλ) and the absolute value of the long‐term population growth rate (|log λ|) were associated with short‐term climate variability. We used empirical data (≥ 20 consecutive years of annual abundances) from 59 wild populations in the Northern Hemisphere, and quantified variabilities in population growth rates and climatic conditions (temperature and precipitation in active and inactive seasons) calculated over four‐ and eight‐year sliding time windows. We observed a positive relationship between the variability of growth rate (CVλ) and the variability of temperature in the active season at the shorter timescale only. Moreover, |log λ| was positively associated with the variability of precipitation in the inactive season at both timescales. Otherwise, the direction of the relationships between population dynamics and climate variability (if any) depended largely on the season and organismal group in question. Both CVλ and |log λ| correlated negatively with species' lifespan, indicating general differences in population dynamics between short‐lived and long‐lived species that were not related to climate variability. Our results suggest that although temporal variation in population growth rates and the magnitude of long‐term population growth rates are partially associated with short‐term interannual climate variability, demographic responses to climate fluctuations might still be population‐specific rather than specific to given organismal groups, and driven by other factors than the observed climate variability.

Grey seal Halichoerus grypus recolonisation of the southern Baltic Sea, Danish Straits and Kattegat

The grey seal became locally extinct in the southern Baltic Sea, Danish Straits and Kattegat in the early 1900s after prolonged culling campaigns. Here, we combine national monitoring and anecdotal data from Denmark, Sweden, Germany and Poland to report on the grey seal's recolonisation of those areas and the initial reestablishment of breeding colonies. Grey seal occurrence has steadily increased since year 2003 as evidenced by the coordinated Baltic Sea moult censuses. At the first census in 2003, there were 146 grey seals along the southern Baltic coasts of Sweden and Denmark, ca 1% of the total Baltic Sea population count. Since 2015, this has increased to 2000–2600 grey seals, or ca 7% of the total population count. Since the local extinction, there have been sporadic breeding events in the 1940s on sea ice around Bornholm and in the 1980s and 1990s on haul‐outs in Kattegat. In 2003, the first two pups in the southern Baltic Sea were recorded at R⊘dsand, Denmark. This is to date the only site in the southern Baltic Sea with regular annual pupping since the recolonisation. Since 2000, there have also been sporadic breeding events in Danish Kattegat, southern Sweden, Poland and Germany. At R⊘dsand, there have been at least 3–10 pups recorded every year since initiation of monitoring in 2011, with an increasing tendency until 2017 with 10 pups counted, which subsequently decreased to 5–6 pups annually in 2018–2020. Compared to recolonising events in the Atlantic, the numbers of pups are low. This may be caused by differences in population dynamics, recolonisation distances, habitat and mortality and effects of rehabilitation programmes. It is likely that the breeding distribution will spread throughout the southern Baltic, Danish Straits and Kattegat if appropriate protection measures of seals and haul‐outs are installed.

Catfish Population Characteristics among River Segments with Altered Fluvial Geomorphic Conditions in the Missouri River, Nebraska, USA

AbstractAlteration of river systems around the world has created novel environments that have been fragmented, homogenized, or transformed from their natural state, thus posing challenges for understanding how fish populations function. The Missouri River has undergone significant alteration through reservoir construction and channelization. Channel Catfish Ictalurus punctatus and Flathead Catfish Pylodictis olivaris both reside in various fragmented sections of the river, and there is a substantial gap in knowledge of how catfishes synchronously function in this modified system. From 2009 to 2018, we assessed catfishes with baited hoop nets and low‐frequency electrofishing among four different areas: upper and lower unchannelized segments and upper and lower channelized segments. Differences in population demographics and dynamics occurred for both species among segments. Both the highest and lowest relative abundances for Channel Catfish occurred in channelized segments, and Flathead Catfish relative abundance was lowest in both unchannelized segments. Subadult growth rates for both catfish species were greater in channelized segments. Channel Catfish mortality was highest in channelized segments, which was consistent with the maximum ages found in channelized (age 9) versus unchannelized (age 15) segments. High‐flow events in 2010 and 2011 led to an increase in recruitment, but populations declined in subsequent years. This long‐term assessment revealed spatial and temporal differences in population dynamics among varying levels of anthropogenic alteration. Our study illustrates how river modification and extreme climatological events may impact and structure catfish populations. These data provide a basis for assessing catfish throughout the Missouri River system and offer insight into how catfish populations in other altered large‐river systems might function.

Age–length relationships in UK harbour seals during a period of population decline

Abstract The abundance of harbour seals (Phoca vitulina) in the UK as a whole has increased over the past 10 years, after a 30% decline during the preceding 10 years and two major viral epidemics. However, population trends vary greatly among regions, with those on the east coast of Scotland and in the Northern Isles experiencing dramatic declines since the early 2000s and populations on the west coast being either stable or increasing. The reasons for these differences in population dynamics are unknown. Determining whether there has been a change in somatic growth among populations can assist in assessing potential causes for abundance declines, as shifts in juvenile growth rates or maximum length at maturity may indicate changes in environmental conditions. Resource limitations are likely to result in slower growth and later age at sexual maturity, whereas causes of acute mortality could have the opposite effect. Here, analysis of the most comprehensive length‐at‐age dataset for UK harbour seals found no evidence for major differences, or changes over time, in asymptotic length or growth parameters from fitted von Bertalanffy growth curves, across all regions, with the exception of one pairwise comparison; males from East Scotland were significantly shorter than males from all other areas by an average of almost 9 cm. However, the power to detect small changes was limited by measurement uncertainty and differences in spatial and temporal sampling effort. Asymptotic lengths at maturity across all regions were slightly lower than published lengths for harbour seal populations in Europe, the Arctic, and Canada, with females being on average 140.5 cm (95% confidence interval 139.4, 141.6 cm) and males 149.4 cm (95% confidence interval 147.8, 151.1 cm) at adulthood. Reliable estimates of changes in growth over time are important for understanding environmental constraints on a population, but knowledge of the underlying drivers of change is essential for the design of robust conservation and mitigation plans.

Microhabitat Heterogeneity and Population Ecology of Ribbed Mussels (Geukensia demissa) Near Their Northern Range Limit (Maritime Canada)

Population dynamics of sessile marine invertebrates are potentially affected by variation in abiotic variables among microhabitats. The ribbed mussel (Geukensia demissa), an ecosystem engineer in salt marshes from Cape Cod to northern Florida, inhabits two microhabitats in salt marshes near its northern range limit, Maritime Canada: the exposed seaward edge of the marsh (edge) and the edge of creeks (creek). To determine differences in population dynamics of ribbed mussels between these microhabitats, population, demographic, and abiotic variables were measured at multiple sites over 1 to 2 years. Water flow was higher, temperature less variable, and winter shoreline disturbance less prevalent along creeks than edges. Mussels showed some minor demographic differences between microhabitats: a slightly delayed onset of gametogenesis, and a tendency to lower female reproductive output and more settlers (although overall numbers were low) within creeks. These differences did not translate into consistent differences in population variables across microhabitat types, namely density, size structure, and individual growth of juveniles and adults. Although creeks appear to be more suitable habitat based on abiotic variables measured, mussel population variables may be limited by a combination of temperature and food availability or quality, or some other factor. Overall, population dynamics of ribbed mussels are similar between creek and edge microhabitats in salt marshes in Maritime Canada. This study contributes a first assessment of the dynamics of a potentially key salt marsh species near its northern range limit.

Geographic-Specific Capture–Recapture Models Reveal Contrasting Migration and Survival Rates of Adult Horseshoe Crabs (Limulus polyphemus)

American horseshoe crabs (Limulus polyphemus) have varied migration patterns and harvesting pressure throughout their range, potentially leading to regional differences in population dynamics. Here, a multi-state mark–recapture model was used to estimate annual survival and exchange rates of adult horseshoe crabs across three geographic regions in Long Island, NY (South Shore, North Shore, and Jamaica Bay areas). Under the New York Horseshoe Crab Monitoring program, a total of 22,525 adult horseshoe crabs were tagged and 879 (3.9%) unique recaptures were observed from 2007 to 2016. Model-averaged annual survival in the North Shore population was higher at 68% (95% confidence interval (CI) 61.9–73.4) when compared to the South Shore (56.8%, 95% CI 51.1–62.2) and Jamaica Bay (54.5%, 95% CI 47.0–61.7) regions. Differences in survival between the North Shore and South Shore may reflect the greater harvest pressure directed along the South Shore. Contrary to expectations for a primarily closed region, Jamaica Bay survival was low, but not attributable to reported harvest related activities. Annual movement from the Jamaica Bay into the adjacent South Shore region was 19.8% (95% CI 13.1–28.9), but annual exchange rates ranging from 0.5 to 5.0% were observed between other regions. For example, movement from the South Shore and North Shore into Jamaica Bay was 3.5% (95% CI 2.3–5.9) and 0.5% (95% CI 0.0–1.0), respectively. There was strong support for sex-specific differences in survival, primarily driven by the low survival of females in Jamaica Bay (33.8%, 95% CI 21.1–50.5). Our findings reveal potential management implications, such as regional survival differences within a uniformly managed stock, and net emigration from a predominantly closed to open harvest region reducing the effectiveness of a protected area.

Differences in Population Dynamics and Uptake of Reproductive Health Services in the Urban and Rural Cohorts of Cross River Health and Demographic Surveillance System of Southern Nigeria

Background: Health and demographic surveillance systems (HDSSs) generate essential health and demographic data from longitudinal surveillance of populations resident in distinctly demarcated enumeration areas. The Cross River HDSS (CRHDSS) located in southern Nigeria includes distinct urban and rural cohorts. Concurrent surveillance of adjacent urban and rural communities provides an opportunity to identify differences in population characteristics and access or utilization of health services. In this paper, we report the result of comparative analysis of rural and urban cohorts of the CRHDSS from November 2012 to December 2018. Methodology: Data was collected through house-to-house interviews performed in 6-monthly cycles through the years. Information obtained included demographic characteristics, pregnancies, child birth, health-seeking behaviour, migration and deaths. Trained field workers collected data from all households in the demographic surveillance area with mobile Android devices (running the ODKCollect). Collected data were transferred electronically to a remote server running on ODKAggregate and further processed by MirthConnect on OpenHDS web application with a MySQL backend database. Data was exported, cleaned and analyzed with the R Statistical Computing Software. Results: Total population undergoing longitudinal health and demographic surveillance was 37,808 persons in 9,452 households with 18,414 males and 19,394 females. The rural cohort made up 47.4% of the population while the urban cohort was 52.6%. Population structure showed that while the rural cohort has a relative depletion of young adults, the urban cohort has preponderance of this population segment indicating the high rate of rural to urban migration. There is also a striking difference in pattern of utilization of reproductive health services by pregnant women. While 68.6% of childbirth in the rural cohort occurred outside the formal health service (at TBAs and at home), 79.1% of childbirth in the urban area occurred in formal health facilities. Both the crude fertility rate, infant mortality and under-five mortality rates were higher in rural than the urban cohorts. Conclusion: Surveillance data showed relative depletion of young adults from rural population cohort, suggesting high rate of rural to urban migration. Majority of childbirths in rural areas still occur outside formal health facilities, which may partly contribute to higher infant mortality rate in the rural cohort. This calls for more efforts to enhance reproductive health services and employment opportunities in rural areas. Keywords: Population, Health characteristics, births, deaths, health and demographic surveillance systems DOI : 10.7176/DCS/9-5-08 Publication date :May 31 st 2019

Differentiation of Russian Territories according to the Population Trends at the Municipal Level

The subject of the research is territorial differences in population dynamics at the levels of municipalities, Russian federal subjects and federal districts. The purpose of the research was to analyze the population trends in urban districts and municipal regions of Russia in recent years highlighting the most problem areas. It is revealed that the socio-demographic security of many territories is threatened by a rapid decline in the population — by more than 2% annually. Already in the medium term, such territories may almost completely lose their population. The components of this process are defined — natural movement of population or migration leading to depopulation. The population changes in Russia as a whole in recent years are shown, including natural population growth in 2013– 2015, gradual increase in the average life expectancy, etc. But in general, the demographic crisis of the last decades is continuing as follows from the comparison with other countries close to Russia in terms of the population make-up or economic development level. In the coming years, assuming the current trends remain, the crisis will become more acute according to the preliminary data on the population decline in Russia in 2018. It is concluded that the population of the municipalities of the Far Eastern Federal District is declining at the fastest rates, which runs counter to the socio-economic development strategy of Russia giving priority specifically to the Far East of the country in the medium and long terms. It is proposed to set up programs of demographic development not only at the level of federal districts and Russian Federation subjects but also at the intraregional level.

Altitude, habitat type and herbivore damage interact in their effects on plant population dynamics.

Insects represent one of the most abundant groups of herbivores, and many of them have significant impacts on the dynamics of plant populations. As insects are very sensitive to changes in climatic conditions, we hypothesize that their effects on plant population dynamics will depend on climatic conditions. Knowledge of the variation in herbivore effects on plant population dynamics is, however, still rather sparse. We studied population dynamics and herbivore damage at the individual plant level of Salvia nubicola along a wide altitudinal gradient representing a range of climatic conditions. Using integral projection models, we estimated the effect of changes in herbivore pressure on plant populations in different climates and habitat types. Since we recorded large differences in the extent of herbivore damage along the altitudinal gradient, we expected that the performance of plants from different altitudes would be affected to different degrees by herbivores. Indeed, we found that populations from low altitudes were better able to withstand increased herbivore damage, while populations from high altitudes were suppressed by herbivores. However, the pattern described above was evident only in populations from open habitats. In forest habitats, the differences in population dynamics between low and high altitudes were largely diminished. The effects of herbivores on plants from different altitudes were thus largely habitat specific. Our results indicate potential problems for plant populations from high altitudes in open habitats because of increased herbivore damage. However, forest habitats may provide refuges for the plants at these high altitudes.

Genetic Differentiation of Glossina pallidipes Tsetse Flies in Southern Kenya.

The tsetse fly Glossina pallidipes, the major vector of the parasite that causes animal African trypanosomiasis in Kenya, has been subject to intense control measures with only limited success. The G. pallidipes population dynamics and dispersal patterns that underlie limited success in vector control campaigns remain unresolved, and knowledge on genetic connectivity can provide insights, and thereby improve control and monitoring efforts. We therefore investigated the population structure and estimated migration and demographic parameters in G. pallidipes using genotypic data from 11 microsatellite loci scored in 250 tsetse flies collected from eight localities in Kenya. Clustering analysis identified two genetically distinct eastern and western clusters (mean between-cluster F ST = 0.202) separated by the Great Rift Valley. We also found evidence of admixture and migration between the eastern and western clusters, isolation by distance, and a widespread signal of inbreeding. We detected differences in population dynamics and dispersal patterns between the western and eastern clusters. These included lower genetic diversity (allelic richness; 7.48 versus 10.99), higher relatedness (percent related individuals; 21.4% versus 9.1%), and greater genetic differentiation (mean within-cluster F ST; 0.183 versus 0.018) in the western than the eastern cluster. Findings are consistent with the presence of smaller, less well-connected populations in Western relative to eastern Kenya. These data suggest that recent anthropogenic influences such as land use changes and vector control programs have influenced population dynamics in G. pallidipes in Kenya, and that vector control efforts should include some region-specific strategies to effectively control this disease vector.

Interactions between species attributes explain population dynamics in stream fishes under changing climate

AbstractSpecies responses to climate change have been shown to vary in both direction and magnitude. Understanding these idiosyncratic responses is crucial if we are to predict extinction risk and set up efficient conservation strategies. The variations observed across species have been related to several species attributes including intrinsic traits such as physiological tolerances or life‐history strategies but also to niche characteristics (e.g., niche breadth [NB], niche position [NP]). However, although previous studies have successfully linked species attributes to population dynamics or range shifts, few have considered synergistic effects to explain responses to climate variations. Here, we assessed whether five species attributes (fecundity, thermal safety margin, trophic position [TP], NB, and NP) explained interspecific differences in four parameters influencing population dynamics of 35 stream fish species at the French scale. We used Bayesian N‐mixture models to estimate posterior distributions of the growth rate, the strength of density dependence, and the influence of both mean temperature and temperature variability on populations for each species. We then used phylogenetic generalized least squares (PGLS) models to investigate the influence of species attributes and their interactions on interspecific differences in each of the four parameter driving population dynamics. The percentage of variance explained by the PGLS models was relatively high (around 40% on average), indicating that species attributes are good predictors of species population dynamics. Furthermore, we showed that the influence of these single attributes was mediated by other attributes, especially NP and TP. Importantly, we found that models including interaction terms had greater support over simple additive models in explaining interspecific differences in population dynamics. Taken together, these results point to the importance of considering the interplay between species attributes in unraveling the mechanisms involved in population dynamics and understanding the vulnerability of species to global change.