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Dive into the research topics where Kim A. Medley is active.

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Featured researches published by Kim A. Medley.


Molecular Ecology | 2015

Human-aided and natural dispersal drive gene flow across the range of an invasive mosquito.

Kim A. Medley; David G. Jenkins; Eric A. Hoffman

Human‐aided transport is responsible for many contemporary species introductions, yet the contribution of human‐aided transport to dispersal within non‐native regions is less clear. Understanding dispersal dynamics for invasive species can streamline mitigation efforts by targeting routes that contribute disproportionally to spread. Because of its limited natural dispersal ability, rapid spread of the Asian tiger mosquito (Aedes albopictus) has been attributed to human‐aided transport, but until now, the relative roles of human‐aided and natural movement have not been rigorously evaluated. Here, we use landscape genetics and information‐theoretic model selection to evaluate 52 models representing 9240 pairwise dispersal paths among sites across the US range for Ae. albopictus and show that recent gene flow reflects a combination of natural and human‐aided dispersal. Highways and water availability facilitate dispersal at a broad spatial scale, but gene flow is hindered by forests at the current distributional limit (range edge) and by agriculture among sites within the mosquitos native climatic niche (range core). Our results show that highways are important to genetic structure between range‐edge and range‐core pairs, suggesting a role for human‐aided mosquito transport to the range edge. In contrast, natural dispersal is dominant at smaller spatial scales, reflecting a shifting dominance to natural movement two decades after introduction. These conclusions highlight the importance of (i) early intervention for species introductions, particularly those with readily dispersed dormant stages and short generation times, and (ii) strict monitoring of commercial shipments for transported immature stages of Ae. albopictus, particularly towards the northern edge of the US range.


Hydrobiologia | 2009

Effect of main-stem dams on zooplankton communities of the Missouri River (USA)

John E. Havel; Kim A. Medley; Kelli D. Dickerson; Theodore R. Angradi; David W. Bolgrien; Paul A. Bukaveckas; Terri M. Jicha

The persistence of plankton in flowing water presents an enigma, i.e., how can populations be sustained while constantly losing individuals downriver? We examined the distribution and abundance of zooplankton from 146 sites on the Missouri River (USA) and found large shifts in the dominance of major taxa between management zones of this regulated river. Crustacean zooplankton were dominant in the inter-reservoir zone of the river, and their taxonomic composition was similar to regional lakes and reservoirs. The exponential decline of cladocerans and copepods with distance from main-stem dams suggests that conditions within the river are adverse to population growth and that reservoirs are the main source of these crustaceans in the river. Rotifers dominated in the channelized zone of the river. High algal biomass and rapid population growth rates likely allow persistence of rotifers in segments of the river that do not receive direct reservoir inputs. Rotifers were less abundant in the inter-reservoir zone, suggesting that their numbers are limited by internal processes, such as food or predators. Since zooplankton are known to be an important food for larval fishes in rivers, this shift of major taxa in regulated rivers has implications for river food webs.


PLOS ONE | 2018

Genetic and environmental influences on the size-fecundity relationship in Aedes albopictus (Diptera: Culicidae): Impacts on population growth estimates?

Katie S. Costanzo; Katie M. Westby; Kim A. Medley

Population growth models are integral to ecological studies by providing estimates of population performance across space and time. Several models have been developed that estimate population growth through correlates of demographic traits, as measuring each parameter of the model can be prohibitive in experimental studies. Since differences in female size can accurately reflect changes in fecundity for many taxa, Livdahl and Sugihara developed a population growth index that incorporates size-fecundity relationships as a proxy for fecundity. To investigate the extent to which this model is robust to variation of this proxy, we tested if genetic (source population), temperature and resource treatments affect the size-fecundity relationship in Aedes albopictus (Skuse), the Asian tiger mosquito. We then determined if variation in the size-fecundity relationship alters the population growth estimates, lambda (λ’), when applied to Livdahl and Sugihara’s model. We performed 2 laboratory experiments in which we reared cohorts of four different geographic populations of A. albopictus across 5 temperature treatments (18, 21, 25, 18, 31°C) and three resource treatments (low, medium, high larval resources). We determined if the slope of the size-fecundity relationship varied by source population, temperature, or resource; and if variation in this relationship affects lambda (λ’) estimates in a competition study between A. albopictus and Culex pipiens (Linnaeus), the northern house mosquito. Temperature treatments significantly affected the size-fecundity relationship, resource level marginally affected the relationship, while source population had no effect. We found positive relationships between size and fecundity when mosquito larvae were reared at high temperatures and low resource levels but the relationship disappeared when mosquitoes were reared at a low temperature or with high levels of resources. The variation in the size-fecundity relationship produced from different temperatures resulted in statistically different lambda (λ’) estimates. However, these changes in lambda (λ’) did not alter the trends in the population performance across treatments or conclusions of the competition study. This study provides evidence that the population growth model is sensitive to variation in size-fecundity relationships and we recommend biologists apply the most compatible size-fecundity relationship to the models to obtain the most accurate estimates of population performance.


Journal of Medical Entomology | 2018

Landscape Physiognomy Influences Abundance of the Lone Star Tick, Amblyomma americanum (Ixodida: Ixodidae), in Ozark Forests

Thomas Van Horn; Solny A. Adalsteinsson; Katie M. Westby; Elizabeth G. Biro; Jonathan Myers; Marko J. Spasojevic; Maranda L. Walton; Kim A. Medley

Abstract The lone star tick, Amblyomma americanum Linnaeus (Ixodida: Ixodidae), is emerging as an important human disease vector in the United States. While some recent studies have modeled broad-scale (regional or county-level) distribution patterns of A. americanum, less is known about how local-scale habitat characteristics drive A. americanum abundance. Such local-scale information is vital to identify targets for tick population control measures within land management units. We investigated how habitat features predict host-seeking A. americanum adult and nymph abundance within a 12-ha oak-hickory forest plot in the Missouri Ozarks. We trapped ticks using CO2-baited traps at 40 evenly spaced locations for three 24-h periods during the summer of 2015, and we measured biotic and abiotic variables surrounding each location. Of 2,008 A. americanum captured, 1,009 were nymphs, and 999 were adults. We observed spatial heterogeneity in local tick abundance (min = 0 ticks, max = 112 ticks, mean = 16.7 ticks per trap night). Using generalized linear mixed models, we found that both nymphs and adults had greater abundance in valleys as well as on northern-facing aspects. Moreover, nymph abundance was negatively related to temperature variance, while adult abundance had a negative relationship with elevation. These results demonstrate that managers in this region may be able to predict local tick abundance through simple physiognomic factors and use these parameters for targeted management action.


Global Ecology and Biogeography | 2010

Niche shifts during the global invasion of the Asian tiger mosquito, Aedes albopictus Skuse (Culicidae), revealed by reciprocal distribution models

Kim A. Medley


Diversity and Distributions | 2011

Pine invasions: climate predicts invasion success; something else predicts failure.

Martin A. Nuñez; Kim A. Medley


Biological Conservation | 2011

Combining genetic structure and ecological niche modeling to establish units of conservation: A case study of an imperiled salamander

Sarah E. May; Kim A. Medley; Steve A. Johnson; Eric A. Hoffman


Agriculture, Ecosystems & Environment | 2015

Intense ranchland management tips the balance of regional and local factors affecting wetland community structure

Kim A. Medley; Elizabeth H. Boughton; David G. Jenkins; John E. Fauth; Patrick J. Bohlen; Pedro F. Quintana-Ascencio


Archive | 2011

Biogeography of Microscopic Organisms: Microbes as a test of biogeographic principles

David G. Jenkins; Kim A. Medley; Rima B. Franklin


Archive | 2018

Can prescribed fire reduce tick parasitism of birds

Leslie A. Sterling; Kim A. Medley; Katie M. Westby; Solný Adalsteinsson

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Katie M. Westby

Washington University in St. Louis

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David G. Jenkins

University of Central Florida

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Elizabeth G. Biro

Washington University in St. Louis

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Eric A. Hoffman

University of Central Florida

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Maranda L. Walton

Washington University in St. Louis

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Solny A. Adalsteinsson

Washington University in St. Louis

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Thomas Van Horn

Washington University in St. Louis

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David W. Bolgrien

United States Environmental Protection Agency

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Elizabeth H. Boughton

University of Central Florida

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