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Prescriptions for the Control of a Clonal Invasive Species Using Demographic Models. PLANTS 2022; 11:plants11050689. [PMID: 35270159 PMCID: PMC8912375 DOI: 10.3390/plants11050689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/18/2022] [Accepted: 01/21/2022] [Indexed: 11/17/2022]
Abstract
Until recently, little research has focused on determination of the population dynamics of invasive species and evaluating their genetic variation. Consequently, not much is known of what drives clonal invasive species and their demography. Here, we describe the population dynamics of Kalanchoe delagoensis (Crassulaceae), considered invasive to several countries. We quantified the demography of a population in central Mexico using integral projection models (IPM) in a population that reproduced asexually exclusively through plantlets. The effect of clonal recruitment on population growth rate (λ) was evaluated by changing plantlet survival and simulating management scenarios that used previous data of watering and seven experimental herbicide treatments. The finite rate of population increase indicated that this Kalanchoe delagoensis population is growing (above one) and with water availability, growth rates will only accelerate. The IPM showed that plantlet survival and recruitment were the most critical steps in the cycle for the population, and simulations of different management scenarios showed that reducing plantlet survival significantly decreased λ only in two out of the seven herbicides used.
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Holmes KH, Lindquist JL, Rebarber R, Werle R, Yerka M, Tenhumberg B. Modeling the evolution of herbicide resistance in weed species with a complex life cycle. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e02473. [PMID: 34652876 DOI: 10.1002/eap.2473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/17/2021] [Accepted: 04/21/2021] [Indexed: 06/13/2023]
Abstract
A growing number of weed species have evolved resistance to herbicides in recent years, which causes an immense financial burden to farmers. An increasingly popular method of weed control is the adoption of crops that are resistant to specific herbicides, which allows farmers to apply the herbicide during the growing season without harming the crop. If such crops are planted in the presence of closely related weed species, it is possible that resistance genes could transfer from the crop species to feral populations of the wild species via gene flow and become stably introgressed under ongoing selective pressure by the herbicide. We use a density-dependent matrix model to evaluate the effect of planting such crops on the evolution of herbicide resistance under a range of management scenarios. Our model expands on previous simulation studies by considering weed species with a more complex life cycle (perennial, rhizomatous weed species), studying the effect of environmental variation in herbicide effectiveness, and evaluating the role of common simplifying genetic assumptions on resistance evolution. Our model predictions are qualitatively similar to previous modeling studies using species with a simpler life cycle, which is, crop rotation in combination with rotation of herbicide site of action effectively controls weed populations and slows the evolution of herbicide resistance. We find that ignoring the effect of environmental variation can lead to an over- or under-prediction of the speed of resistance evolution. The effect of environmental variation in herbicide effectiveness depends on the resistance allele frequency in the weed population at the beginning of the simulation. Finally, we find that degree of dominance and ploidy level have a much larger effect on the predicted speed of resistance evolution compared to the rate of gene flow.
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Affiliation(s)
- K Harrison Holmes
- Department of Mathematics, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588, USA
| | - John L Lindquist
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588, USA
| | - Richard Rebarber
- Department of Mathematics, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588, USA
| | - Rodrigo Werle
- Department of Agronomy, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Melinda Yerka
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada-Reno, Reno, Nevada, 89557, USA
| | - Brigitte Tenhumberg
- School of Biological Sciences and Department of Mathematics, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588, USA
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Reichenbach M, Rebarber R, Tenhumberg B. Spectral properties of a non-compact operator in ecology. J Math Biol 2021; 82:50. [PMID: 33847821 DOI: 10.1007/s00285-021-01600-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 02/22/2021] [Accepted: 03/24/2021] [Indexed: 11/29/2022]
Abstract
Ecologists have recently used integral projection models (IPMs) to study fish and other animals which continue to grow throughout their lives. Such animals cannot shrink, since they have bony skeletons; a mathematical consequence of this is that the kernel of the integral projection operator T is unbounded, and the operator is not compact. To our knowledge, all theoretical work done on IPMs has assumed the operator is compact, and in particular has a bounded kernel. A priori, it is unclear whether these IPMs have an asymptotic growth rate [Formula: see text], or a stable-stage distribution [Formula: see text]. In the case of a compact operator, these quantities are its spectral radius and the associated eigenvector, respectively. Under biologically reasonable assumptions, we prove that the non-compact operators in these IPMs share some important traits with their compact counterparts: the operator T has a unique positive eigenvector [Formula: see text] corresponding to its spectral radius [Formula: see text], this [Formula: see text] is strictly greater than the supremum of the modulus of all other spectral values, and for any nonnegative initial population [Formula: see text], there is a [Formula: see text] such that [Formula: see text].
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Affiliation(s)
- Matt Reichenbach
- Geospatial Research Laboratory, US Army Corps of Engineers - Engineer Research and Development Center, 7701 Telegraph Road, Alexandria, VA, 22315, USA.
| | - Richard Rebarber
- Department of Mathematics, University of Nebraska-Lincoln, 203 Avery Hall, Lincoln, NE68588-0130, USA
| | - Brigitte Tenhumberg
- Department of Mathematics, University of Nebraska-Lincoln, 203 Avery Hall, Lincoln, NE68588-0130, USA.,School of Biological Sciences, University of Nebraska-Lincoln, 402 Manter Hall, Lincoln, NE, 68588, USA
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Demographic effects of interacting species: exploring stable coexistence under increased climatic variability in a semiarid shrub community. Sci Rep 2021; 11:3099. [PMID: 33542350 PMCID: PMC7862631 DOI: 10.1038/s41598-021-82571-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 01/14/2021] [Indexed: 11/23/2022] Open
Abstract
Population persistence is strongly determined by climatic variability. Changes in the patterns of climatic events linked to global warming may alter population dynamics, but their effects may be strongly modulated by biotic interactions. Plant populations interact with each other in such a way that responses to climate of a single population may impact the dynamics of the whole community. In this study, we assess how climate variability affects persistence and coexistence of two dominant plant species in a semiarid shrub community on gypsum soils. We use 9 years of demographic data to parameterize demographic models and to simulate population dynamics under different climatic and ecological scenarios. We observe that populations of both coexisting species may respond to common climatic fluctuations both similarly and in idiosyncratic ways, depending on the yearly combination of climatic factors. Biotic interactions (both within and among species) modulate some of their vital rates, but their effects on population dynamics highly depend on climatic fluctuations. Our results indicate that increased levels of climatic variability may alter interspecific relationships. These alterations might potentially affect species coexistence, disrupting competitive hierarchies and ultimately leading to abrupt changes in community composition.
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Leland Russell F, McMinn RL, Konrade LA, Beck JB. Population Sizes, Rhinocyllus conicus Use, and Patterns of Genetic Variation of Cirsium ownbeyi, a Rare Native Thistle, in Wyoming. WEST N AM NATURALIST 2019. [DOI: 10.3398/064.079.0102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- F. Leland Russell
- Department of Biological Sciences, Wichita State University, Wichita, KS 67260-0026
| | - Robby L. McMinn
- Department of Botany, University of Wyoming, Laramie, WY 82071
| | | | - James B. Beck
- Department of Biological Sciences, Wichita State University, Wichita, KS 67260-0026
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Tenhumberg B, Crone EE, Ramula S, Tyre AJ. Time-lagged effects of weather on plant demography: drought and Astragalus scaphoides. Ecology 2018; 99:915-925. [PMID: 29380874 DOI: 10.1002/ecy.2163] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 12/20/2017] [Accepted: 01/02/2018] [Indexed: 01/05/2023]
Abstract
Temperature and precipitation determine the conditions where plant species can occur. Despite their significance, to date, surprisingly few demographic field studies have considered the effects of abiotic drivers. This is problematic because anticipating the effect of global climate change on plant population viability requires understanding how weather variables affect population dynamics. One possible reason for omitting the effect of weather variables in demographic studies is the difficulty in detecting tight associations between vital rates and environmental drivers. In this paper, we applied Functional Linear Models (FLMs) to long-term demographic data of the perennial wildflower, Astragalus scaphoides, and explored sensitivity of the results to reduced amounts of data. We compared models of the effect of average temperature, total precipitation, or an integrated measure of drought intensity (standardized precipitation evapotranspiration index, SPEI), on plant vital rates. We found that transitions to flowering and recruitment in year t were highest if winter/spring of year t was wet (positive effect of SPEI). Counterintuitively, if the preceding spring of year t - 1 was wet, flowering probabilities were decreased (negative effect of SPEI). Survival of vegetative plants from t - 1 to t was also negatively affected by wet weather in the spring of year t - 1 and, for large plants, even wet weather in the spring of t - 2 had a negative effect. We assessed the integrated effect of all vital rates on life history performance by fitting FLMs to the asymptotic growth rate, log(λt). Log(λt) was highest if dry conditions in year t - 1 were followed by wet conditions in the year t. Overall, the positive effects of wet years exceeded their negative effects, suggesting that increasing frequency of drought conditions would reduce population viability of A. scaphoides. The drought signal weakened when reducing the number of monitoring years. Substituting space for time did not recover the weather signal, probably because the weather variables varied little between sites. We detected the SPEI signal when the analysis included data from two sites monitored over 20 yr (2 × 20 observations), but not when analyzing data from four sites monitored over 10 yr (4 × 10 observations).
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Affiliation(s)
- Brigitte Tenhumberg
- School of Biological Sciences and Department of Mathematics, University of Nebraska, Lincoln, Nebraska, 68588, USA
| | - Elizabeth E Crone
- Department of Biology, Tufts University, Medford, Massachusetts, 02155, USA
| | - Satu Ramula
- Section of Ecology, Department of Biology, University of Turku, FI-20014, Turku, Finland
| | - Andrew J Tyre
- School of Natural Resources, University of Nebraska, Lincoln, Nebraska, 68583, USA
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Crandall RM, Knight TM. Role of multiple invasion mechanisms and their interaction in regulating the population dynamics of an exotic tree. J Appl Ecol 2017. [DOI: 10.1111/1365-2664.13020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Raelene M. Crandall
- Biology Department University of Missouri‐St. Louis St. Louis MO USA
- School of Forest Resources and Conservation University of Florida Gainesville FL USA
| | - Tiffany M. Knight
- Department of Community Ecology Helmholtz Centre for Environmental Research‐UFZ Halle (Saale) Germany
- Institute of Biology Martin Luther University Halle‐Wittenberg Halle (Saale) Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Leipzig Germany
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Affiliation(s)
- Alden B. Griffith
- Environmental Studies Program, Wellesley College; 106 Central Street Wellesley MA 02481 USA
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Schultz EL, Eckberg JO, Berg SS, Louda SM, Miller TEX. Native insect herbivory overwhelms context dependence to limit complex invasion dynamics of exotic weeds. Ecol Lett 2017; 20:1374-1384. [PMID: 28901044 DOI: 10.1111/ele.12833] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 06/03/2017] [Accepted: 08/07/2017] [Indexed: 12/01/2022]
Abstract
Understanding the role of consumers in density-dependent plant population dynamics is a long-standing goal in ecology. However, the generality of herbivory effects across heterogeneous landscapes is poorly understood due to the pervasive influence of context-dependence. We tested effects of native insect herbivory on the population dynamics of an exotic thistle, Cirsium vulgare, in a field experiment replicated across eight sites in eastern Nebraska. Using hierarchical Bayesian analysis and density-dependent population models, we found potential for explosive low-density population growth (λ > 5) and complex density fluctuations under herbivore exclusion. However, herbivore access drove population decline (λ < 1), suppressing complex fluctuations. While plant-herbivore interaction outcomes are famously context-dependent, we demonstrated that herbivores suppress potentially invasive populations throughout our study region, and this qualitative outcome is insensitive to environmental context. Our novel use of Bayesian demographic modelling shows that native insect herbivores consistently prevent hard-to-predict fluctuations of weeds in environments otherwise susceptible to invasion.
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Affiliation(s)
- Emily L Schultz
- Program in Ecology and Evolutionary Biology, Department of BioSciences, Rice University, Houston, TX, 77005, USA
| | - James O Eckberg
- School of Biological Sciences, University of Nebraska, Lincoln, NE, 68588, USA
| | - Sergey S Berg
- Department of Computer and Information Sciences, University of St. Thomas, Saint Paul, MN, 55105, USA
| | - Svata M Louda
- School of Biological Sciences, University of Nebraska, Lincoln, NE, 68588, USA
| | - Tom E X Miller
- Program in Ecology and Evolutionary Biology, Department of BioSciences, Rice University, Houston, TX, 77005, USA
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Aschehoug ET, Brooker R, Atwater DZ, Maron JL, Callaway RM. The Mechanisms and Consequences of Interspecific Competition Among Plants. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2016. [DOI: 10.1146/annurev-ecolsys-121415-032123] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
During the past 100 years, studies spanning thousands of taxa across almost all biomes have demonstrated that competition has powerful negative effects on the performance of individuals and can affect the composition of plant communities, the evolution of traits, and the functioning of whole ecosystems. In this review, we highlight new and important developments that have the potential to greatly improve our understanding of how plants compete and the consequences of competition from individuals to communities in the following major areas of research: (a) mechanisms of competition, (b) competitive effect and response, (c) direct and indirect effects of competition, (d) population-level effects of competition, (e) biogeographical differences in competition, and (f) conditionality of competition. Ecologists have discovered much about competition, but the mechanisms of competition and how competition affects the organization of communities in nature still require both theoretical and empirical exploration.
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Affiliation(s)
- Erik T. Aschehoug
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Rob Brooker
- The James Hutton Institute, Aberdeen AB15 8QH, Scotland, United Kingdom
| | - Daniel Z. Atwater
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - John L. Maron
- Division of Biological Sciences, University of Montana, Missoula, Montana 59812
| | - Ragan M. Callaway
- Division of Biological Sciences, University of Montana, Missoula, Montana 59812
- The Institute on Ecosystems, University of Montana, Missoula, Montana 59812
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