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Vander Zanden MJ, Gorsky A, Hansen GJA, Johnson PTJ, Latzka AW, Mikulyuk A, Rohwer RR, Spear MJ, Walsh JR. Nine Lessons about Aquatic Invasive Species from the North Temperate Lakes Long-Term Ecological Research (NTL-LTER) Program. Bioscience 2024; 74:509-523. [PMID: 39229622 PMCID: PMC11367673 DOI: 10.1093/biosci/biae062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 03/07/2024] [Accepted: 05/30/2024] [Indexed: 09/05/2024] Open
Abstract
Freshwater ecosystems can serve as model systems that reveal insights into biological invasions. In this article, we summarize nine lessons about aquatic invasive species from the North Temperate Lakes Long-Term Ecological Research program and affiliated projects. The lessons about aquatic invasive species are as follows: Invasive species are more widespread than has been documented; they are usually at low abundance; they can irrupt from low-density populations in response to environmental triggers; they can occasionally have enormous and far-reaching impacts; they can affect microbial communities; reservoirs act as invasive species hotspots; ecosystem vulnerability to invasion can be estimated; invasive species removal can produce long-term benefits; and the impacts of invasive species control may be greater than the impacts of the invasive species. This synthesis highlights how long-term research on a freshwater landscape can advance our understanding of invasions.
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Affiliation(s)
- M Jake Vander Zanden
- Center for Limnology at the University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Adrianna Gorsky
- Center for Limnology at the University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Gretchen J A Hansen
- Department of Fisheries, Wildlife, Conservation Biology at the University of Minnesota, Twin Cities, Minnesota, United States
| | - Pieter T J Johnson
- Department of Ecology and Evolutionary Biology at the University of Colorado Boulder, Boulder, Colorado, United States
| | - Alexander W Latzka
- Wisconsin Department of Natural Resources, Madison, Wisconsin, United States
| | - Alison Mikulyuk
- Aquatic Sciences Center at the University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Robin R Rohwer
- Department of Integrative Biology at the University of Texas at Austin, Austin, Texas, United States
| | - Michael J Spear
- Illinois River Biological Station, at the University of Illinois Urbana-Champaign, Havana, Illinois, United States
| | - Jake R Walsh
- Department of Fisheries, Wildlife, Conservation Biology at the University of Minnesota, Twin Cities, Minnesota, United States
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2
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Kvistad JT, Galarowicz TL, Clapp DF, Chadderton WL, Tucker AJ, Annis G, Herbert M. Evidence of a compensatory response in invasive Rusty Crayfish ( Faxonius rusticus) following intensive harvest removal from northern Lake Michigan fish spawning reefs. Biol Invasions 2023; 25:1-17. [PMID: 37362907 PMCID: PMC10166462 DOI: 10.1007/s10530-023-03076-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 04/25/2023] [Indexed: 06/28/2023]
Abstract
The goal of most invasive species suppression programs is to achieve long-term sustained reductions in population abundance, yet removal programs can be stymied by density-dependent population responses. We tested a harvest removal strategy for invasive Rusty Crayfish (Faxonius rusticus) at two nearshore native fish spawning habitats in northern Lake Michigan. Changes in average Rusty Crayfish densities were evaluated with a before-after reference-impact study design. We removed 3182 Rusty Crayfish, primarily adults (> 20 mm carapace length), at two sites over two harvest seasons, expending 17,825 trap days in effort. Generalized linear modeling results suggested a statistically significant reduction in Rusty Crayfish densities was achieved at one reef, Little Traverse Bay (LTB Crib). Reduced densities were sustained over the egg maturation period for native fish and into the following year after removal ceased. By late summer/early fall, between consecutive suppression efforts in 2018 and 2019, we observed a threefold increase in pre-removal densities. Size-frequency histograms from diver quadrat surveys showed higher abundances of juvenile (< 20 mm carapace length) size classes the following spring and summer at LTB Crib compared to its paired reference site. Stock-recruit curves fit to count data, pooled across all sites, provided further evidence of density-dependence. With a proviso that we only conducted two seasons of consecutive suppression, this study highlights an important aspect of invasive species management and raises questions about the efficacy of adult-only crayfish removal strategies. Supplementary Information The online version contains supplementary material available at 10.1007/s10530-023-03076-6.
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Affiliation(s)
- Jake T. Kvistad
- Department of Biology, Biosciences 2100, Central Michigan University, Mount Pleasant, MI 48859 USA
- Cramer Fish Sciences, Watershed Sciences Laboratory, 1125 12th Avenue NW, Suite B-1, Issaquah, WA 98027 USA
| | - Tracy L. Galarowicz
- Department of Biology, Biosciences 2100, Central Michigan University, Mount Pleasant, MI 48859 USA
| | - David F. Clapp
- Michigan Department of Natural Resources, Charlevoix Fisheries Research Station, 96 Grant Street, Charlevoix, MI 49720 USA
| | - William L. Chadderton
- The Nature Conservancy, 721 Flanner Hall, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Andrew J. Tucker
- The Nature Conservancy, 721 Flanner Hall, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Gust Annis
- The Nature Conservancy, 101 E. César E. Chávez Avenue, Lansing, MI 48906 USA
| | - Matthew Herbert
- The Nature Conservancy, 101 E. César E. Chávez Avenue, Lansing, MI 48906 USA
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3
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The bioeconomic paradox of market-based invasive species harvest: a case study of the commercial lionfish fishery. Biol Invasions 2023. [DOI: 10.1007/s10530-023-02998-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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4
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Guzy JC, Falk BG, Smith BJ, Willson JD, Reed RN, Aumen NG, Avery ML, Bartoszek IA, Campbell E, Cherkiss MS, Claunch NM, Currylow AF, Dean T, Dixon J, Engeman R, Funck S, Gibble R, Hengstebeck KC, Humphrey JS, Hunter ME, Josimovich JM, Ketterlin J, Kirkland M, Mazzotti FJ, McCleery R, Miller MA, McCollister M, Parker MR, Pittman SE, Rochford M, Romagosa C, Roybal A, Snow RW, Spencer MM, Waddle JH, Yackel Adams AA, Hart KM. Burmese pythons in Florida: A synthesis of biology, impacts, and management tools. NEOBIOTA 2023. [DOI: 10.3897/neobiota.80.90439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Burmese pythons (Python molurus bivittatus) are native to southeastern Asia, however, there is an established invasive population inhabiting much of southern Florida throughout the Greater Everglades Ecosystem. Pythons have severely impacted native species and ecosystems in Florida and represent one of the most intractable invasive-species management issues across the globe. The difficulty stems from a unique combination of inaccessible habitat and the cryptic and resilient nature of pythons that thrive in the subtropical environment of southern Florida, rendering them extremely challenging to detect. Here we provide a comprehensive review and synthesis of the science relevant to managing invasive Burmese pythons. We describe existing control tools and review challenges to productive research, identifying key knowledge gaps that would improve future research and decision making for python control.
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5
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González-Calderón A, Schiavini A. Reproductive rates of invasive Castor canadensis respond to management in Tierra del Fuego, Argentina. Mamm Biol 2022. [DOI: 10.1007/s42991-022-00296-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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6
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Using the red‐imported fire ant to study invasive species removal and reinvasion. Ecosphere 2022. [DOI: 10.1002/ecs2.4075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Jaramillo JM, Ma J, van den Driessche P, Yakubu AA. Disease-Induced Hydra Effect with Overcompensatory Recruitment. Bull Math Biol 2021; 84:17. [PMID: 34923617 DOI: 10.1007/s11538-021-00975-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 11/18/2021] [Indexed: 11/27/2022]
Abstract
In ecological systems, the hydra effect is an increase in population size caused by an increase in mortality. This seemingly counterintuitive effect has been observed in several populations, including fish, blowflies, snails and plants, and has been modeled in both continuous and discrete time. A similar effect induced by disease has recently been observed empirically. Here we present theoretical and simulation results for an infectious disease-induced hydra effect, namely conditions under which the total population size, composed of those that are infectious as well as those that are susceptible, at an endemic equilibrium is greater than the population size at the disease-free equilibrium. (For an endemic k-cycle, this can be similarly defined using the average population.) We find this disease-induced hydra effect occurs when the intra-specific competition is strong and disease infection sufficiently inhibits the reproductive output of infected individuals. For our continuous time model, we give a necessary and sufficient condition for a disease-induced hydra effect. This condition requires overcompensatory recruitment. With a discrete time model, we show there is no disease-induced hydra effect without overcompensatory recruitment. We illustrate by simulations that a disease-induced hydra effect may occur with Ricker recruitment when the endemic system converges to either a fixed equilibrium or a 2-cycle.
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Affiliation(s)
- J M Jaramillo
- Department of Mathematics and Statistics, University of Victoria, Victoria, BC, V8W 2Y2, Canada.
| | - Junling Ma
- Department of Mathematics and Statistics, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - P van den Driessche
- Department of Mathematics and Statistics, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Abdul-Aziz Yakubu
- Department of Mathematics, Howard University, Washington, DC, 20059, USA
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8
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Vimercati G, Davies SJ, Hui C, Measey J. Cost-benefit evaluation of management strategies for an invasive amphibian with a stage-structured model. NEOBIOTA 2021. [DOI: 10.3897/neobiota.70.72508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Management strategies for invasive populations should be designed to maximise efficacy and efficiency, i.e. to accomplish their goals while operating with the least resource consumption. This optimisation is often difficult to achieve in stage-structured populations, because costs, benefits and feasibility of removing individuals may vary with stage. We use a spatially-explicit stage-structured model to assess efficacy of past, present and alternative control strategies for invasive guttural toads, Sclerophrys gutturalis, in Cape Town. The strategies involve removal of variable proportions of individuals at different life-history stages and spatial scales. We also quantify the time necessary to implement each strategy as a proxy of financial resources and we correct strategy outcomes by implementation of time to estimate efficiency. We found that the strategy initially pursued in Cape Town, which did not target any specific stage, was less efficient than the present strategy, which prioritises adult removal. The initial strategy was particularly inefficient because it did not reduce the population size despite allocating consistent resources to remove eggs and tadpoles. We also found that such removal might be detrimental when applied at high levels. This counter-intuitive outcome is due to the ‘hydra effect’: an undesired increase in population size caused by removing individuals before overcompensatory density dependence. Strategies that exclusively remove adults ensure much greater management efficiency than those that also remove eggs and tadpoles. Available management resources should rather be allocated to increase the proportion of adult guttural toads that are removed or the spatial extent at which this removal is pursued.
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Pittman SE, Bartoszek IA. Initial dispersal behavior and survival of non-native juvenile Burmese pythons (Python bivittatus) in South Florida. BMC ZOOL 2021; 6:33. [PMID: 37170339 PMCID: PMC10124209 DOI: 10.1186/s40850-021-00098-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 11/10/2021] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Dispersal behavior is a critical component of invasive species dynamics, impacting both spatial spread and population density. In South Florida, Burmese pythons (Python bivittatus) are an invasive species that disrupt ecosystems and have the potential to expand their range northward. Control of python populations is limited by a lack of information on movement behavior and vital rates, especially within the younger age classes. We radio-tracked 28 Burmese pythons from hatching until natural mortality for approximately 3 years. Pythons were chosen from 4 clutches deposited by adult females in 4 different habitats: forested wetland, urban interface, upland pine, and agricultural interface.
Results
Known-fate survival estimate was 35.7% (95% CI = 18% - 53%) in the first 6 months, and only 2 snakes survived 3 years post hatching. Snakes moving through ‘natural’ habitats had higher survival than snakes dispersing through ‘modified’ habitats in the first 6- months post-hatching. Predation was the most common source of mortality. Snakes from the agricultural interface utilized canals and displayed the largest net movements.
Conclusions
Our results suggest that pythons may have lower survival if clutches are deposited in or near urbanized areas. Alternatively, juvenile pythons could quickly disperse to new locations by utilizing canals that facilitate linear movement. This study provides critical information about behavioral and life history characteristics of juvenile Burmese pythons that will inform management practices.
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10
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What’s for dinner? Assessing the value of an edible invasive species and outreach actions to promote its consumption. Biol Invasions 2021. [DOI: 10.1007/s10530-021-02685-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Davis ACD, Akins L, Pollock C, Lundgren I, Johnston MA, Castillo B, Reale‐Munroe K, McDonough V, Moneysmith S, Green SJ. Multiple drivers of invasive lionfish culling efficiency in marine protected areas. CONSERVATION SCIENCE AND PRACTICE 2021. [DOI: 10.1111/csp2.541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
| | - Lad Akins
- Frost Museum of Science Miami Florida USA
- Reef Environmental Education Foundation Key Largo Florida USA
| | - Clayton Pollock
- Buck Island Reef National Monument St. Croix Virgin Islands USA
| | - Ian Lundgren
- Buck Island Reef National Monument St. Croix Virgin Islands USA
| | | | - Bernard Castillo
- University of the Virgin Islands Saint Thomas Virgin Islands USA
| | | | | | | | - Stephanie J. Green
- University of Alberta Alberta Canada
- Reef Environmental Education Foundation Key Largo Florida USA
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12
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Garain K, Mandal PS. Bubbling and hydra effect in a population system with Allee effect. ECOLOGICAL COMPLEXITY 2021. [DOI: 10.1016/j.ecocom.2021.100939] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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13
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Stage-specific overcompensation, the hydra effect, and the failure to eradicate an invasive predator. Proc Natl Acad Sci U S A 2021; 118:2003955118. [PMID: 33727416 DOI: 10.1073/pnas.2003955118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
As biological invasions continue to increase globally, eradication programs have been undertaken at significant cost, often without consideration of relevant ecological theory. Theoretical fisheries models have shown that harvest can actually increase the equilibrium size of a population, and uncontrolled studies and anecdotal reports have documented population increases in response to invasive species removal (akin to fisheries harvest). Both findings may be driven by high levels of juvenile survival associated with low adult abundance, often referred to as overcompensation. Here we show that in a coastal marine ecosystem, an eradication program resulted in stage-specific overcompensation and a 30-fold, single-year increase in the population of an introduced predator. Data collected concurrently from four adjacent regional bays without eradication efforts showed no similar population increase, indicating a local and not a regional increase. Specifically, the eradication program had inadvertently reduced the control of recruitment by adults via cannibalism, thereby facilitating the population explosion. Mesocosm experiments confirmed that adult cannibalism of recruits was size-dependent and could control recruitment. Genomic data show substantial isolation of this population and implicate internal population dynamics for the increase, rather than recruitment from other locations. More broadly, this controlled experimental demonstration of stage-specific overcompensation in an aquatic system provides an important cautionary message for eradication efforts of species with limited connectivity and similar life histories.
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Neale JT, Juliano SA. Predation yields greater population performance: What are the contributions of density- and trait-mediated effects? ECOLOGICAL ENTOMOLOGY 2021; 46:56-65. [PMID: 34092899 PMCID: PMC8171192 DOI: 10.1111/een.12940] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
1. Population responses to extrinsic mortality can yield no change in number of survivors (compensation) or an increase in number of survivors (overcompensation) when the population is regulated by negative density-dependence. This intriguing response has been the subject of theoretical studies, but few experiments have explored how the source of extrinsic mortality affects the response. 2. This study tests abilities of three functionally diverse predators, alone and combined, to induce (over)compensation of a prey population. Larval Aedes aegypti (Diptera: Culicidae) were exposed to predation by Mesocyclops longisetus (Crustacea: Copepoda), Anopheles barberi (Diptera: Culicidae), Corethrella appendiculata (Diptera: Corethrellidae), all three in a substitutive design, or no predation. 3. The number of survivors to adulthood, female size and development time, and a composite index of performance (r') were analysed. Predator treatment did not have a significant effect on total number of survivors, nor on number of males, suggesting mortality by predation was compensatory. Predation significantly affected number of female survivors, with a trend of more females produced with predation, though no post hoc tests were significant. Predation significantly increased female development rate and r' relative to no-predator control. 4. A sensitivity analysis indicated that the change in the number of female adults produced was the largest contributing factor to the differences in r' among cohorts. While predation did not significantly increase overall production of adults, it did release survivors from density-dependent effects sufficiently to increase population performance. This study provides an empirical test of mechanisms by which predation may yield positive effects on a population of victims, a phenomenon predicted to occur across many taxa and food webs.
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Taylor AT, Bangs MR, Long JM. Sibship reconstruction with SNPs illuminates the scope of a cryptic invasion of Asian Swamp Eels (Monopterus albus) in Georgia, USA. Biol Invasions 2020. [DOI: 10.1007/s10530-020-02384-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Malishev M, Civitello DJ. Modelling how resource competition among snail hosts affects the mollusciciding frequency and intensity needed to control human schistosomes. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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17
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Anjos LD, Costa MIDS, Almeida RC. Characterizing the existence of hydra effect in spatial predator-prey models and the influence of functional response types and species dispersal. Ecol Modell 2020. [DOI: 10.1016/j.ecolmodel.2020.109109] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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18
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Day CC, Landguth EL, Simmons RK, Baker WP, Whiteley AR, Lukacs PM, Bearlin A. Simulating effects of fitness and dispersal on the use of Trojan sex chromosomes for the management of invasive species. J Appl Ecol 2020. [DOI: 10.1111/1365-2664.13616] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Casey C. Day
- Computational Ecology Lab University of Montana Missoula MT USA
| | | | - Ryan K. Simmons
- Seattle City Light Environment, Land and Licensing Seattle WA USA
| | | | - Andrew R. Whiteley
- Wildlife Biology Program Franke College of Forestry and Conservation University of Montana Missoula MT USA
| | - Paul M. Lukacs
- Wildlife Biology Program Franke College of Forestry and Conservation University of Montana Missoula MT USA
| | - Andrew Bearlin
- Seattle City Light Environment, Land and Licensing Seattle WA USA
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Abstract
AbstractThreshold harvesting removes the surplus of a population above a set threshold and takes no harvest below the threshold. This harvesting strategy is known to prevent overexploitation while obtaining higher yields than other harvesting strategies. However, the harvest taken can vary over time, including seasons of no harvest at all. While this is undesirable in fisheries or other exploitation activities, it can be an attractive feature of management strategies where removal interventions are costly and desirable only occasionally. In the presence of population fluctuations, the issue of variable harvests and population sizes becomes even more notorious. Here, we investigate the impact of threshold harvesting on the dynamics of both population size and harvests, especially in the presence of population cycles. We take into account semelparous and iteroparous life cycles, Allee effects, observation uncertainty, and demographic as well as environmental stochasticity, using generic mathematical models in discrete time. Our results show that threshold harvesting enhances multiple forms of population stability, namely persistence, constancy, resilience, and dynamic stability. We discuss plausible choices of threshold values, depending on whether the aim is resource exploitation, pest control, or the stabilization of fluctuations.
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Abstract
Invasive predatory lake trout Salvelinus namaycush were discovered in Yellowstone Lake in 1994 and caused a precipitous decrease in abundance of native Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri. Suppression efforts (primarily gillnetting) initiated in 1995 did not curtail lake trout population growth or lakewide expansion. An adaptive management strategy was developed in 2010 that specified desired conditions indicative of ecosystem recovery. Population modeling was used to estimate effects of suppression efforts on the lake trout and establish effort benchmarks to achieve negative population growth (λ < 1). Partnerships enhanced funding support, and a scientific review panel provided guidance to increase suppression gillnetting effort to >46,800 100-m net nights; this effort level was achieved in 2012 and led to a reduction in lake trout biomass. Total lake trout biomass declined from 432,017 kg in 2012 to 196,675 kg in 2019, primarily because of a 79% reduction in adults. Total abundance declined from 925,208 in 2012 to 673,983 in 2019 but was highly variable because of recruitment of age-2 fish. Overall, 3.35 million lake trout were killed by suppression efforts from 1995 to 2019. Cutthroat trout abundance remained below target levels, but relative condition increased, large individuals (> 400 mm) became more abundant, and individual weights doubled, probably because of reduced density. Continued actions to suppress lake trout will facilitate further recovery of the cutthroat trout population and integrity of the Yellowstone Lake ecosystem.
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Walsworth TE, Landom K, Gaeta JW. Compensatory recruitment, dynamic habitat, and selective gear present challenges to large‐scale invasive species control. Ecosphere 2020. [DOI: 10.1002/ecs2.3158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Timothy E. Walsworth
- Department of Watershed Sciences and the Ecology Center Utah State University Logan Utah 84322 USA
| | - Kevin Landom
- Department of Watershed Sciences and the Ecology Center Utah State University Logan Utah 84322 USA
| | - Jereme W. Gaeta
- Department of Watershed Sciences and the Ecology Center Utah State University Logan Utah 84322 USA
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22
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Sjodin BMF, Irvine RL, Ford AT, Howald GR, Russello MA. Rattus population genomics across the Haida Gwaii archipelago provides a framework for guiding invasive species management. Evol Appl 2020; 13:889-904. [PMID: 32431741 PMCID: PMC7232760 DOI: 10.1111/eva.12907] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/18/2019] [Accepted: 12/05/2019] [Indexed: 11/29/2022] Open
Abstract
Invasive species have led to precipitous declines in biodiversity, especially in island systems. Brown (Rattus norvegicus) and black rats (R. rattus) are among the most invasive animals on the planet, with eradication being the primary tool for established island populations. The need for increased research for defining eradication units and monitoring outcomes has been highlighted as a means to maximize success. Haida Gwaii is an archipelago ~100 km off the northern coast of British Columbia, Canada, that hosts globally significant breeding populations of seabirds that are at risk due to invasive rats. Here, we paired sampling of brown (n = 287) and black (n = 291) rats across the Haida Gwaii archipelago with genotyping by sequencing (10,770-27,686 SNPs) to investigate patterns of population connectivity and infer levels/direction of gene flow among invasive rat populations in Haida Gwaii. We reconstructed three regional clusters for both species (north, central and south), with proximate populations within regions being largely more related than those that were more distant, consistent with predictions from island biogeography theory. Population assignment of recently detected individuals post-eradication on Faraday, Murchison and the Bischof Islands revealed all were re-invaders from Lyell Island, rather than being on-island survivors. Based on these results, we identified six eradication units constituting single or clusters of islands that would limit the potential for reinvasion, some of which will need to be combined with biosecurity measures. Overall, our results highlight the importance of targeted research prior to conducting eradications and demonstrate a framework for applying population genomics for guiding invasive species management in island systems.
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Affiliation(s)
| | - Robyn L. Irvine
- Gwaii Haanas National Park ReserveNational Marine Conservation Area Reserve and Haida Heritage SiteSkidegateBCCanada
| | - Adam T. Ford
- Department of BiologyUniversity of British ColumbiaKelownaBCCanada
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23
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Preston DL, Sauer EL. Infection pathology and competition mediate host biomass overcompensation from disease. Ecology 2020; 101:e03000. [PMID: 32012250 DOI: 10.1002/ecy.3000] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/23/2019] [Accepted: 01/23/2020] [Indexed: 11/08/2022]
Abstract
Predators can increase the biomass of their prey, particularly when prey life stages differ in competitive ability and predation is stage specific. Akin to predators, parasites influence host population sizes and engage in stage-structured interactions, yet whether parasites can increase host population biomass remains relatively unexplored. Using a stage-structured consumer-resource model and a mesocosm experiment with snails and castrating trematodes, we examined responses of host biomass to changes in infection prevalence under variation in host pathology and resource competition. Equilibrium adult host biomass increased with infection prevalence in the model when parasites castrated hosts and adults were superior competitors to juveniles. Juvenile biomass increased with infection prevalence whether parasites caused mortality or castration, but only when juveniles were superior competitors. In mesocosms, increases in infection by castrating trematodes reduced snail egg production, juvenile abundance, and adult survival. At high competition, juvenile growth and total biomass increased with infection prevalence due to competitive release. At low competition, juvenile biomass decreased with infection due to reduced reproduction. These results highlight how disease-induced biomass overcompensation depends on infection pathology, resource availability, and competitive interactions within and between host life stages. Considering such characteristics may benefit biocontrol efforts using parasites.
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Affiliation(s)
- Daniel L Preston
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Erin L Sauer
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
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Monitoring, modeling and harvest management of non-native invasive green iguanas on Grand Cayman, Cayman Islands. Biol Invasions 2020. [DOI: 10.1007/s10530-020-02233-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
AbstractThe green iguana (Iguana iguana) was most likely introduced as a pet and became overabundant during the last 20 years on Grand Cayman. Because negative impacts were unmanageable (e.g., damage to buildings and other infrastructure), a harvest management strategy was developed and implemented, and over 874,252 green iguanas were removed between October 2018 and August 2019. Distance sampling surveys were conducted to estimate abundance in February 2019 and annually in August 2014–2019. Abundance estimates were used to develop a Bayesian state-space logistic model, generate the posterior distributions of population and harvest management parameters, and make future predictions of abundance for August 2020–2030. Abundance increased over fivefold between August 2014 and 2018, from an average of 254,162 to 1,319,939 green iguanas. However, after harvesting for 5 months, abundance declined to an average of 600,113 green iguanas in February 2019; and after 11 months, abundance declined to an average of 103,020 green iguanas in August 2019. Maximum population growth rate averaged 1.552, carrying capacity averaged 1,611,013, equilibrium abundance averaged 805,506, maximum sustainable total harvest averaged 628,491, and maximum sustainable harvest rate averaged 0.776. With harvest rates between 0.600 and 0.800, predicted abundance averaged 28,751 green iguanas for August 2020–2030. However, harvest mortality may have unforeseen outcomes due to the release from density dependence and overcompensation through high survival and fecundity rates. Because natural resource managers have partial control over harvesting and incomplete understanding of green iguana population dynamics, monitoring and modeling are essential to assess population response and guide harvest management decisions.
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Raj S, Kumar AB, Raghavan R, Dahanukar N. Amazonian invaders in an Asian biodiversity hotspot: Understanding demographics for the management of the armoured sailfin catfish, Pterygoplichthys pardalis in Kerala, India. JOURNAL OF FISH BIOLOGY 2020; 96:549-553. [PMID: 31875320 DOI: 10.1111/jfb.14243] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 12/20/2019] [Indexed: 06/10/2023]
Abstract
Invasion of armoured catfish, Pterygoplichthys spp., is a major threat to global aquatic biodiversity, and developing effective strategies for their control and eradication is both a concern and a research priority. A length-based population assessment of invasive Pterygoplichthys pardalis in southern India, a hotspot for endemic aquatic biodiversity, indicated that rapid growth, high growth performance index and continuous recruitment have aided their successful invasion. Increasing fishing pressure on the adults is not adequate for population management, and only targeting young individuals (<30 cm) will result in overexploitation and population collapse.
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Affiliation(s)
- Smrithy Raj
- Department of Aquatic Biology and Fisheries, University of Kerala, Thiruvananthapuram, India
| | | | - Rajeev Raghavan
- Department of Fisheries Resource Management, Kerala University of Fisheries and Ocean Studies, Kochi, India
- Center for Aquatic Resource Management and Conservation, Kerala University of Fisheries and Ocean Studies, Kochi, India
| | - Neelesh Dahanukar
- Indian Institute of Science Education and Research, Pune, India
- Zoo Outreach Organization, Coimbatore, Tamil Nadu, India
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Camp EV, Kaemingk MA, Ahrens RNM, Potts WM, Pine WE, Weyl OLF, Pope KL. Resilience Management for Conservation of Inland Recreational Fisheries. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2019.00498] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Neale JT, Juliano SA. Finding the sweet spot: What levels of larval mortality lead to compensation or overcompensation in adult production? Ecosphere 2019; 10. [PMID: 31803516 DOI: 10.1002/ecs2.2855] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Extrinsic mortality impinging on negatively density-dependent populations can result in no change in the number of survivors (compensation) or an increase (overcompensation) by releasing the population from density-dependent effects on survivorship. The relationship between the level of extrinsic mortality (i.e., percentage of mortality) and the level and likelihood of overcompensation is theoretically important, but rarely investigated. We tested the hypothesis that overcompensation occurs below a threshold value of extrinsic mortality that is related to density-dependent mortality rate, and that additive extrinsic mortality occurs above this threshold. This hypothesis predicts that survivorship vs. extrinsic mortality will: 1) be best described by a two-segmented model with a threshold; 2) have a slope >0 below the threshold; and 3) have a slope=-1 above the threshold. We also tested whether mortality imposed by real predators and random harvest have equivalent effects on adult production, and whether magnitude of overcompensation is related to species sensitivity to density-dependence. These hypotheses were tested in the container mosquitoes Aedes aegypti, A. albopictus, A. triseriatus, and Culex pipiens (Diptera: Culicidae). Cohorts of 150 larvae were exposed to random harvest of 0-70% two days after hatch or to predation by 1-3 Mesocyclops longisetus (Crustacea: Copepoda). Overcompensation occurred in A. aegypti in a pattern consistent with predictions. Aedes triseriatus showed strong overcompensation but no evidence of a threshold, whereas A. albopictus and C. pipiens had survival consistent with compensatory mortality but no evidence of a threshold. Compared to random harvest, mortality from predation yielded greater adult production in A. aegypti and A. albopictus, lesser adult production in C. pipiens, and no difference in adult production in A. triseriatus. Our results are largely consistent with our hypothesis about overcompensation, with the caveat that thresholds for additive mortality appear to occur at very high levels of extrinsic mortality. Magnitudes of overcompensation for the three Aedes were inversely related to survival in the 0% mortality treatment, consistent with our hypothesis that overcompensation is related to sensitivity to density-dependence. A broad range of extrinsic mortality levels can yield overcompensation, which may have practical implications for attempts to control pest populations.
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Affiliation(s)
- Joseph T Neale
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790-4120 USA
| | - Steven A Juliano
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790-4120 USA
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Ower GD, Juliano SA. Effects of larval density on a natural population of Culex restuans (Diptera: Culicidae): No evidence of compensatory mortality. ECOLOGICAL ENTOMOLOGY 2019; 44:197-205. [PMID: 31178624 PMCID: PMC6550488 DOI: 10.1111/een.12689] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 09/27/2018] [Indexed: 06/09/2023]
Abstract
1. We investigated the effects of strong density-dependence on larval growth, development, and survival of the mosquito Culex restuans (Theobald). We tested the hypothesis that density reduction early in larval development could result in as many or more individuals surviving to adulthood (compensation or overcompensation, respectively), or increased reproductive performance via rapid development and greater adult size. 2. In a field study of a natural population of C. restuans we tested for the effects of a 75% lower density on percent survivorship to adulthood, number of adults, development time, adult size, adult longevity, and size dependent fecundity. 3. We found no evidence for compensation or overcompensation in adult production, nor for effects of lower density on percent survivorship. Low density yielded significant increases in adult size, adult longevity, and size-dependent fecundity, and a decrease in development time. 4. Estimated per capita population growth rate was significantly greater in the low-density treatment than in the high-density treatment. We infer this difference resulted from greater per capita resources increasing female size and fecundity, and reducing development time. Greater per capita population growth could therefore result from early mortality of larvae, meaning that the hydra effect, which predicts greater equilibrium population with, as opposed to without, extrinsic mortality, may be possible for these mosquitoes.
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Affiliation(s)
- Geoffrey D. Ower
- School of Biological Sciences, Illinois State University, Normal, IL 61790-4120
| | - Steven A. Juliano
- School of Biological Sciences, Illinois State University, Normal, IL 61790-4120
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Beggs R, Tulloch AIT, Pierson J, Blanchard W, Crane M, Lindenmayer D. Patch-scale culls of an overabundant bird defeated by immediate recolonization. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01846. [PMID: 30835909 DOI: 10.1002/eap.1846] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 10/26/2018] [Accepted: 12/04/2018] [Indexed: 06/09/2023]
Abstract
Overabundant native animals cause a variety of human-wildlife conflicts that can require management to reduce their social, environmental, or economic impacts. Culling is an intuitively attractive management response to overabundance, but poor monitoring of results and costs means that evidence for successful outcomes is often lacking. Furthermore, many culls worldwide have been ineffective or counterproductive due to ecological release mechanisms or compensatory responses by the overabundant species. We completed a controlled, replicated, costed, and rigorously monitored experimental cull of the endemic Australian honeyeater, the Noisy Miner (Manorina melanocephala). Aggressive exclusion of birds from remnant woodland patches by overabundant Noisy Miners is listed as a Key Threatening Process under Australian conservation legislation due to its impacts on threatened birds. The problem is particularly prevalent in the highly modified agricultural landscapes of eastern Australia. The species impacts avian assemblages at low densities (0.6-0.8 birds/ha) and at a subcontinental scale (>1 million km2 ). Some ecologists recommend culling as the only management response capable of timely reversal of declines of threatened small woodland birds. We monitored Noisy Miner abundance before and for 12 months after a culling program and found that immediate recolonization from the surrounding landscape negated the impact of the cull. We hypothesize that this is due to a vacuum effect; whereby, birds resident in more marginal habitat around treatment patches move into the vacant territory post-cull. Modeled mean abundance of Noisy Miners declined by 22% in treatment sites compared to an increase of 4% in control sites in the post-cull period. Abundance in all sites, however, remained three to five times higher than published ecological impact thresholds. Return on investment analysis indicated no relationship between culling effort and reduction in Noisy Miner abundance. We conclude that culling at a patch scale is not an efficient method of reducing Noisy Miner abundance to levels unlikely to impact threatened woodland birds in the highly modified study landscape, despite estimated costs 18 times lower than another potential management response of revegetation. Our study highlights the importance of building empirical evidence before intuitively attractive but not necessarily ecologically effective management responses are applied more widely.
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Affiliation(s)
- Richard Beggs
- Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - Ayesha I T Tulloch
- Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- Centre of Excellence for Environmental Decisions, Centre for Biodiversity and Conservation Science, The University of Queensland, St Lucia, Queensland, 4072, Australia
| | - Jennifer Pierson
- Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- Tidbinbilla Nature Reserve, Parks & Conservation Service, Australian Capital Territory Government, Tharwa, Australian Capital Territory, 2620, Australia
| | - Wade Blanchard
- Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - Mason Crane
- Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - David Lindenmayer
- Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, 2601, Australia
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DiRenzo GV, Che‐Castaldo C, Saunders SP, Campbell Grant EH, Zipkin EF. Disease-structured N-mixture models: A practical guide to model disease dynamics using count data. Ecol Evol 2019; 9:899-909. [PMID: 30766679 PMCID: PMC6362444 DOI: 10.1002/ece3.4849] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 12/05/2018] [Indexed: 11/25/2022] Open
Abstract
Obtaining inferences on disease dynamics (e.g., host population size, pathogen prevalence, transmission rate, host survival probability) typically requires marking and tracking individuals over time. While multistate mark-recapture models can produce high-quality inference, these techniques are difficult to employ at large spatial and long temporal scales or in small remnant host populations decimated by virulent pathogens, where low recapture rates may preclude the use of mark-recapture techniques. Recently developed N-mixture models offer a statistical framework for estimating wildlife disease dynamics from count data. N-mixture models are a type of state-space model in which observation error is attributed to failing to detect some individuals when they are present (i.e., false negatives). The analysis approach uses repeated surveys of sites over a period of population closure to estimate detection probability. We review the challenges of modeling disease dynamics and describe how N-mixture models can be used to estimate common metrics, including pathogen prevalence, transmission, and recovery rates while accounting for imperfect host and pathogen detection. We also offer a perspective on future research directions at the intersection of quantitative and disease ecology, including the estimation of false positives in pathogen presence, spatially explicit disease-structured N-mixture models, and the integration of other data types with count data to inform disease dynamics. Managers rely on accurate and precise estimates of disease dynamics to develop strategies to mitigate pathogen impacts on host populations. At a time when pathogens pose one of the greatest threats to biodiversity, statistical methods that lead to robust inferences on host populations are critically needed for rapid, rather than incremental, assessments of the impacts of emerging infectious diseases.
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Affiliation(s)
- Graziella V. DiRenzo
- Department of Integrative Biology, College of Natural ScienceMichigan State UniversityEast LansingMichigan
| | | | - Sarah P. Saunders
- Department of Integrative Biology, College of Natural ScienceMichigan State UniversityEast LansingMichigan
- National Audubon SocietyEast LansingMichigan
| | - Evan H. Campbell Grant
- SO Conte Anadromous Fish Research Lab, Patuxent Wildlife Research CenterU.S. Geological SurveyTurners FallsMassachusetts
| | - Elise F. Zipkin
- Department of Integrative Biology, College of Natural ScienceMichigan State UniversityEast LansingMichigan
- Ecology, Evolutionary Biology, and Behavior ProgramMichigan State UniversityEast LansingMichigan
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Luellen DR, LaGuardia MJ, Tuckey TD, Fabrizio MC, Rice GW, Hale RC. Assessment of legacy and emerging contaminants in an introduced catfish and implications for the fishery. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:28355-28366. [PMID: 30083900 DOI: 10.1007/s11356-018-2801-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/19/2018] [Indexed: 06/08/2023]
Abstract
Since introduction into the Chesapeake Bay watershed in the 1970s, blue catfish (Ictalurus furcatus) populations have increased, impacting native species. One strategy suggested to limit their growing numbers is to expand the existing commercial fishery. However, the promotion of human consumption of this large, omnivorous fish may increase exposure to contaminants of concern (COC). However, there are few published data on contaminants in blue catfish. To evaluate this possibility, we measured COC (PCBs, PBDEs, OCs, Hg) in individual fillets and compared levels to established consumption advisory limits. James River (near Richmond, Virginia) and Upper Potomac River (downstream of Washington DC) fish exhibited higher burdens of most COC than those from the lower James and rural Rappahannock rivers. Fish sex and δ15N values (surrogate for trophic position) did not correlate with COC concentrations. Potomac River fish exhibited greatest δ15N, perhaps related to local wastewater inputs. Despite differences in human population densities among watersheds, fish mercury (Hg) levels were similar. Most fillets surpassed US EPA advisory limits for unrestricted consumption (> 16 meals/month) for Hg and PCBs. Hg and PCB advisories in the region typically restrict consumption to two 220 g meals/month. Hence, individuals who rely on fish for a large portion of their diet may be exposed to unacceptable Hg and PCB concentrations. COC levels typically increased with fish length; in particular, fish > 550 mm often exceeded unrestricted consumption limits for chlordanes and DDTs. PBDEs, pentachloroanisole, hexachlorobenzene, and mirex levels were generally below established advisories. However, because fish advisories are based on the expected consequences from single contaminants and a single or limited number of toxicological endpoints, consumers face greater risks due to cumulative effects from all coincident COCs, as well as additional exposure pathways, such as other food and air. The additional data on contaminant levels reported here will increase the accuracy of forecasted risks. However, it also illustrates the complexity in communicating the risks from multi-contaminant exposure.
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Affiliation(s)
- Drew R Luellen
- Department of Aquatic Health Sciences, Virginia Institute of Marine Science, College of William & Mary, PO Box 1346, Gloucester Point, VA, 23062, USA.
| | - Mark J LaGuardia
- Department of Aquatic Health Sciences, Virginia Institute of Marine Science, College of William & Mary, PO Box 1346, Gloucester Point, VA, 23062, USA
| | - Troy D Tuckey
- Department of Fisheries Science, Virginia Institute of Marine Science, College of William & Mary, PO Box 1346, Gloucester Point, VA, 23062, USA
| | - Mary C Fabrizio
- Department of Fisheries Science, Virginia Institute of Marine Science, College of William & Mary, PO Box 1346, Gloucester Point, VA, 23062, USA
| | - Gary W Rice
- Department of Chemistry, College of William & Mary, Integrated Science Center 1050, Williamsburg, VA, 23187, USA
| | - Robert C Hale
- Department of Aquatic Health Sciences, Virginia Institute of Marine Science, College of William & Mary, PO Box 1346, Gloucester Point, VA, 23062, USA
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Hamman EA, McCoy MW. Top-down pulses reduce prey population sizes and persistence. Sci Rep 2018; 8:9346. [PMID: 29921899 PMCID: PMC6008325 DOI: 10.1038/s41598-018-27661-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 05/29/2018] [Indexed: 11/09/2022] Open
Abstract
Resource pulses are well documented and have important consequences for population dynamics relative to continuous inputs. However, pulses of top-down factors (e.g. predation) are less explored and appreciated in the ecological literature. Here, we use a simple differential equation population model to show how pulsed removals of individuals from a population alter population size relative to continuous dynamics. Pulsed removals result in lower equilibrium population sizes relative to continuous removals, and the differences are greatest at low population growth rates, high removal rates, and with large, infrequent pulses. Furthermore, the timing of the removal pulses (either stochastic or cyclic) affects population size. For example, cyclic removals are less likely than stochastic removals to result in population eradication, but when eradication occurs, the time until eradication is shorter for cyclic than with stochastic removals.
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Affiliation(s)
| | - Michael W McCoy
- Department of Biology, East Carolina University, Greenville, USA
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McIntire KM, Juliano SA. How can mortality increase population size? A test of two mechanistic hypotheses. Ecology 2018; 99:1660-1670. [PMID: 29722433 DOI: 10.1002/ecy.2375] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 03/11/2018] [Accepted: 04/12/2018] [Indexed: 11/05/2022]
Abstract
Overcompensation occurs when added mortality increases survival to the next life-cycle stage. Overcompensation can contribute to the Hydra effect, wherein added mortality increases equilibrium population size. One hypothesis for overcompensation is that added mortality eases density dependence, increasing survival to adulthood ("temporal separation of mortality and density dependence"). Mortality early in the life cycle is therefore predicted to cause overcompensation, whereas mortality later in the life cycle is not. Another hypothesis for overcompensation is that threat of mortality (e.g., from predation) causes behavioral changes that reduce overexploitation of resources, allowing resource recovery, and increasing production of adults ("prudent resource exploitation"). Behaviorally active predation cues alone are therefore predicted to cause overcompensation. We tested these predictions in two experiments with larvae of two species of Aedes. As predicted, early mortality yielded greater production of adults, and of adult females, and greater estimated rate of population increase than did later mortality. Addition of water-borne predation cues usually reduced browsing on surfaces in late-stage larvae, but contrary to prediction, resulted in neither significantly greater production of adult mosquitoes nor significantly greater estimated rate of increase. Thus we have strong evidence that timing of mortality contributes to overcompensation and the Hydra effect in mosquitoes. Evidence that predation cues alone can result in overcompensation via prudent resource exploitation is lacking. We expect the overcompensation in response to early mortality will be common in organisms with complex life cycles, density dependence among juveniles, and developmental control of populations.
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Affiliation(s)
- Kristina M McIntire
- School of Biological Sciences, Illinois State University, Normal, Illinois, 61790-4120, USA
| | - Steven A Juliano
- School of Biological Sciences, Illinois State University, Normal, Illinois, 61790-4120, USA
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Civitello DJ, Fatima H, Johnson LR, Nisbet RM, Rohr JR. Bioenergetic theory predicts infection dynamics of human schistosomes in intermediate host snails across ecological gradients. Ecol Lett 2018. [PMID: 29527787 DOI: 10.1111/ele.12937] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Epidemiological dynamics depend on the traits of hosts and parasites, but hosts and parasites are heterogeneous entities that exist in dynamic environments. Resource availability is a particularly dynamic and potent environmental driver of within-host infection dynamics (temporal patterns of growth, reproduction, parasite production and survival). We developed, parameterised and validated a model for resource-explicit infection dynamics by incorporating a parasitism module into dynamic energy budget theory. The model mechanistically explained the dynamic multivariate responses of the human parasite Schistosoma mansoni and its intermediate host snail to variation in resources and host density. At the population level, feedbacks mediated by resource competition could create a unimodal relationship between snail density and human risk of exposure to schistosomes. Consequently, weak snail control could backfire if reductions in snail density release remaining hosts from resource competition. If resource competition is strong and relevant to schistosome production in nature, it could inform control strategies.
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Affiliation(s)
- David J Civitello
- Department of Biology, Emory University, 1510 Clifton Rd NE, 30322, Atlanta, GA, USA
| | - Hiba Fatima
- Global Health Institute, Duke University, Durham, NC, USA
| | - Leah R Johnson
- Department of Statistics, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Roger M Nisbet
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, UCSB, 93106, Santa Barbara, CA, USA
| | - Jason R Rohr
- Department of Integrative Biology, University of South Florida, 4202, East Fowler Ave., 33620, Tampa, FL, USA
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Moro D, Byrne M, Kennedy M, Campbell S, Tizard M. Identifying knowledge gaps for gene drive research to control invasive animal species: The next CRISPR step. Glob Ecol Conserv 2018. [DOI: 10.1016/j.gecco.2017.e00363] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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36
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Density-dependent colonization and natural disturbance limit the effectiveness of invasive lionfish culling efforts. Biol Invasions 2017. [DOI: 10.1007/s10530-017-1449-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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37
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Density dependence in demography and dispersal generates fluctuating invasion speeds. Proc Natl Acad Sci U S A 2017; 114:5053-5058. [PMID: 28442569 DOI: 10.1073/pnas.1618744114] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Density dependence plays an important role in population regulation and is known to generate temporal fluctuations in population density. However, the ways in which density dependence affects spatial population processes, such as species invasions, are less understood. Although classical ecological theory suggests that invasions should advance at a constant speed, empirical work is illuminating the highly variable nature of biological invasions, which often exhibit nonconstant spreading speeds, even in simple, controlled settings. Here, we explore endogenous density dependence as a mechanism for inducing variability in biological invasions with a set of population models that incorporate density dependence in demographic and dispersal parameters. We show that density dependence in demography at low population densities-i.e., an Allee effect-combined with spatiotemporal variability in population density behind the invasion front can produce fluctuations in spreading speed. The density fluctuations behind the front can arise from either overcompensatory population growth or density-dependent dispersal, both of which are common in nature. Our results show that simple rules can generate complex spread dynamics and highlight a source of variability in biological invasions that may aid in ecological forecasting.
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Harvey-Samuel T, Ant T, Alphey L. Towards the genetic control of invasive species. Biol Invasions 2017; 19:1683-1703. [PMID: 28620268 PMCID: PMC5446844 DOI: 10.1007/s10530-017-1384-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 02/11/2017] [Indexed: 11/13/2022]
Abstract
Invasive species remain one of the greatest threats to global biodiversity. Their control would be enhanced through the development of more effective and sustainable pest management strategies. Recently, a novel form of genetic pest management (GPM) has been developed in which the mating behaviour of insect pests is exploited to introduce genetically engineered DNA sequences into wild conspecific populations. These 'transgenes' work in one or more ways to reduce the damage caused by a particular pest, for example reducing its density, or its ability to vector disease. Although currently being developed for use against economically important insect pests, these technologies would be highly appropriate for application against invasive species that threaten biodiversity. Importantly, these technologies have begun to advance in scope beyond insects to vertebrates, which include some of the world's worst invasives. Here we review the current state of this rapidly progressing field and, using an established set of eradication criteria, discuss the characteristics which make GPM technologies suitable for application against invasive pests.
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Effects of strength and timing of harvest on seasonal population models: stability switches and catastrophic shifts. THEOR ECOL-NETH 2016. [DOI: 10.1007/s12080-016-0325-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Mazzotti FJ, Rochford M, Vinci J, Jeffery BM, Eckles JK, Dove C, Sommers KP. Implications of the 2013 Python Challenge®for Ecology and Management ofPython molorus bivittatus(Burmese Python) in Florida. SOUTHEAST NAT 2016. [DOI: 10.1656/058.015.sp807] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Frank J. Mazzotti
- Fort Lauderdale Research and Education Center, University of Florida, 3205 College Avenue, Davie, FL 33314
| | - Mike Rochford
- Fort Lauderdale Research and Education Center, University of Florida, 3205 College Avenue, Davie, FL 33314
| | - Joy Vinci
- Fort Lauderdale Research and Education Center, University of Florida, 3205 College Avenue, Davie, FL 33314
| | - Brian M. Jeffery
- Fort Lauderdale Research and Education Center, University of Florida, 3205 College Avenue, Davie, FL 33314
| | | | - Carla Dove
- Smithsonian Institution, Division of Birds, NHB E-600, MRC 116, Washington, DC 20560
| | - Kristen P. Sommers
- Florida Fish and Wildlife Conservation Commission, 620 South Meridian Street, Tallahassee, FL 32399
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Foss-Grant AP, Zipkin EF, Thorson JT, Jensen OP, Fagan WF. Hierarchical analysis of taxonomic variation in intraspecific competition across fish species. Ecology 2016; 97:1724-1734. [DOI: 10.1890/15-0733.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 11/09/2015] [Accepted: 02/24/2016] [Indexed: 11/18/2022]
Affiliation(s)
| | - Elise F. Zipkin
- Michigan State University Department of Integrative Biology; Michigan State University Ecology, Evolutionary Biology and Behavior Program; East Lansing Michigan 48864 USA
| | - James T. Thorson
- Fisheries Resources Assessment and Monitoring Division; Northwest Fisheries Science Center; National Marine Fisheries Service; NOAA; Seattle Washington 98112 USA
| | - Olaf P. Jensen
- Rutgers University Department of Marine and Coastal Sciences; New Brunswick New Jersey 08901 USA
| | - William F. Fagan
- University of Maryland Department of Biology; College Park Maryland 20742 USA
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Potential Impact of Carry-Over Effects in the Dynamics and Management of Seasonal Populations. PLoS One 2016; 11:e0155579. [PMID: 27171267 PMCID: PMC4865231 DOI: 10.1371/journal.pone.0155579] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 05/01/2016] [Indexed: 11/19/2022] Open
Abstract
For many species living in changing environments, processes during one season influence vital rates in a subsequent season in the same annual cycle. The interplay between these carry-over effects between seasons and other density-dependent events can have a strong influence on population size and variability. We carry out a theoretical study of a discrete semelparous population model with an annual cycle divided into a breeding and a non-breeding season; the model assumes carry-over effects coming from the non-breeding period and affecting breeding performance through a density-dependent adjustment of the growth rate parameter. We analyze the influence of carry-over effects on population size, focusing on two important aspects: compensatory mortality and population variability. To understand the potential consequences of carry-over effects for management, we have introduced constant effort harvesting in the model. Our results show that carry-over effects may induce dramatic changes in population stability as harvesting pressure is increased, but these changes strongly depend on whether harvesting occurs prior to reproduction or after it.
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Wells K, Cassey P, Sinclair RG, Mutze GJ, Peacock DE, Lacy RC, Cooke BD, O'Hara RB, Brook BW, Fordham DA. Targeting season and age for optimizing control of invasive rabbits. J Wildl Manage 2016. [DOI: 10.1002/jwmg.21093] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Konstans Wells
- The Environment Institute and School of Biological SciencesThe University of AdelaideAdelaideSA5005Australia
- Environmental Futures Research InstituteGriffith UniversityBrisbaneQLD4111Australia
| | - Phillip Cassey
- The Environment Institute and School of Biological SciencesThe University of AdelaideAdelaideSA5005Australia
| | - Ron G. Sinclair
- Natural Resources Management Biosecurity UnitBiosecurity SAAdelaideAustralia
| | - Greg J. Mutze
- Natural Resources Management Biosecurity UnitBiosecurity SAAdelaideAustralia
| | - David E. Peacock
- Natural Resources Management Biosecurity UnitBiosecurity SAAdelaideAustralia
| | | | - Brian D. Cooke
- Institute for Applied EcologyUniversity of CanberraCanberraACT2601Australia
| | - Robert B. O'Hara
- Biodiversity and Climate Research Centre (BIK‐F)Senckenberganlage 25, 60325 Frankfurt am MainGermany
| | - Barry W. Brook
- School of Biological SciencesUniversity of TasmaniaHobartTAS7001Australia
| | - Damien A. Fordham
- The Environment Institute and School of Biological SciencesThe University of AdelaideAdelaideSA5005Australia
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44
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Turner BC, de Rivera CE, Grosholz ED, Ruiz GM. Assessing population increase as a possible outcome to management of invasive species. Biol Invasions 2015. [DOI: 10.1007/s10530-015-1026-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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45
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Intra-specific competition in predator can promote the coexistence of an eco-epidemiological model with strong Allee effects in prey. Biosystems 2015; 137:34-44. [DOI: 10.1016/j.biosystems.2015.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 09/04/2015] [Accepted: 09/08/2015] [Indexed: 11/22/2022]
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46
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Karatayev VA, Kraft CE, Zipkin EF. Racing through life: maturation rate plasticity regulates overcompensation and increases persistence. Ecosphere 2015. [DOI: 10.1890/es14-00513.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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47
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A Geospatial Approach for Estimating Suitable Habitat and Population Size of the Invasive Northern Snakehead. JOURNAL OF FISH AND WILDLIFE MANAGEMENT 2015. [DOI: 10.3996/102014-jfwm-075] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Abstract
Northern snakehead Channa argus, an invasive predatory fish species from Asia, may continue to establish itself throughout temperate areas of the eastern United States, particularly in shallow vegetated habitats of ponds and streams. The species was first collected in the Potomac River in 2004 and has become successfully established in several major rivers within the Chesapeake Bay watershed. The objectives of this work were to develop habitat suitability criteria using a novel methodology that combines geographic information systems technology and fish surveys to estimate population sizes. A combination of catch data and reported or empirically derived habitat relationships were used to analyze seasonal distributions (March–October) in two tidal freshwater tributaries of the Potomac River: Nanjemoy Creek (2013) and Chopawamsic Creek (2010–2013). Adults were collected in relatively deeper sections of the streams (average depth 0.7–1.0 m) with a low cover of submerged aquatic vegetation (0–21% of site). Using additional distributional data, we identified suitability criteria as: 1) edges of submerged aquatic vegetation that included 5 m of vegetation and 5 m of adjacent open water; 2) less than 30% of mid-channel distance from shore, which may or may not include submerged aquatic vegetation; and 3) the upper 15% of the tidal freshwater stream. An adult population estimate derived from a suitable area in Pomonkey Creek (a tributary of the Potomac River) and estimated densities from Nanjemoy Creek and Chopawamsic Creek (i.e., three adults/ha) was not different from that expected using electrofishing surveys. Assuming approximately 7,093 ha of suitable habitat and three adults/ha, the number of adults was predicted to be 21,279 for 44 major tidal freshwater tributaries of the Potomac River. This is our first estimate of population size of northern snakehead for any river of the Chesapeake Bay watershed and its accuracy will undoubtedly improve as additional studies report variation in density for other tributaries. Because of the species’ ability to establish itself in temperate climates, it is important to engage the public to prevent additional releases of northern snakehead, especially to vulnerable habitats.
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Schröder A, van Leeuwen A, Cameron TC. When less is more: positive population-level effects of mortality. Trends Ecol Evol 2014; 29:614-24. [DOI: 10.1016/j.tree.2014.08.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 08/22/2014] [Accepted: 08/22/2014] [Indexed: 11/26/2022]
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49
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Braverman E, Chan B. Stabilization of prescribed values and periodic orbits with regular and pulse target oriented control. CHAOS (WOODBURY, N.Y.) 2014; 24:013119. [PMID: 24697381 DOI: 10.1063/1.4865231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Investigating a method of chaos control for one-dimensional maps, where the intervention is proportional to the difference between a fixed value and a current state, we demonstrate that stabilization is possible in one of the two following cases: (1) for small values, the map is increasing and the slope of the line connecting the points on the line with the origin is decreasing; (2) the chaotic map is locally Lipschitz. Moreover, in the latter case we prove that any point of the map can be stabilized. In addition, we study pulse stabilization when the intervention occurs each m-th step and illustrate that stabilization is possible for the first type of maps. In the context of population dynamics, we notice that control with a positive target, even if stabilization is not achieved, leads to persistent solutions and prevents extinction in models which experience the Allee effect.
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Affiliation(s)
- E Braverman
- Department of Mathematics and Statistics, University of Calgary, 2500 University Drive N.W., Calgary AB T2N 1N4, Canada
| | - B Chan
- Department of Mathematics and Statistics, University of Calgary, 2500 University Drive N.W., Calgary AB T2N 1N4, Canada
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50
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Clash of the titans: a multi-species invasion with high gene flow in the globally invasive titan acorn barnacle. Biol Invasions 2014. [DOI: 10.1007/s10530-013-0624-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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