Biological Invasions - The Daniel Simberloff Award
The Award
The Simberloff Award for Outstanding Presentation is named to recognize Simberloff’s many contributions to the study of nonnative species. The award will be given annually to two students at the Ecological Society of America’s annual meeting who embody Simberloff’s creativity, intelligence, and passion for studying and understanding the biology of nonnative organisms. Each award is accompanied by a two-year electronic subscription of Biological Invasions as well as a cash prize of USD 250. Read more (this opens in a new tab)
We are pleased to award Shelby Le Clare and Peter Lutz with the 2023 Simberloff Awards for Outstanding Presentation and Outstanding Poster, respectively, Below is some information that they shared about their research and their favorite Simberloff publications:
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Shelby LeClare, School of Natural Resources and
Environment, University of Florida
Briefly describe your project’s background/question/methods:
Over the past two decades, the establishment and subsequent invasion of the Burmese python (Python molurus bivittatus) in the Greater Everglades ecosystem has become a topic of concern amongst conservation and restoration efforts in South Florida. As such, ongoing, large-scale collaborative efforts have been conducted to assess and mitigate impacts across multiple agencies which have resulted in the removal of thousands of Burmese pythons to date, allowing for the generation of an extensive diet data set utilizing gut-content analysis. With this data, as well as previous work characterizing the Everglades food-web prior to the large-scale proliferation of the python, we constructed a post-invaded food-web and utilized Ecological Network Analysis to quantify and compare the structure and function of the Everglades food-web pre- and post-python invasion. With this systems-oriented methodology we looked to answer three central questions: 1) what niche space is the Burmese python occupying in the food-web? To answer this question, we quantified several ENA node-level metrics that characterize each compartment's functional role within the overall food-web and performed a principal component and cluster analysis where we examined the python’s position within the ordination space. 2) Is there in overall shift in the structure and/or function of the Everglades food-web post invasion? Here we perform a Lindeman Trophic Analysis to look at the efficiency of carbon moving up the food-chain as well as Network Level metrics looking at whole system properties and how these change pre- and post-invasions to assess overall system response. 3) Are these effects were different than we expected from a random invasion utilizing randomized null model simulations where we randomize specific attributes of the Burmese python’s trophic interactions.
Briefly describe your project’s results/conclusions:
Our results suggest that the Burmese python is functionally similar to other snakes within the Everglades Food Web and is acting as a top predator within system most similar to that of the Florida Panther but with greater functional importance regarding carbon flow through the food-web. Additionally, for our second question, although results demonstrate an overall decrease in trophic efficiency throughout the food-web, overall ecosystem function remains relatively stable indicating system resilience. This could be due to the fact the graminoid system is characteristic of high detrivory which is evident in the case only 11% of all incoming carbon flows from the first to the second trophic level which the python demonstrates little impact on. Finally, preliminary analysis of the null model simulations indicates that the Python’s specific diet results in system wide effects that are different than we would expect from a random invasion.
What department and university do you belong to?
School of Natural Resources and Environment, University of Florida
What is your major and year of study at your university?
I am in the final years of my master’s in Interdisciplinary Ecology
Do you belong to a lab? If so please list.
I am co-advised by Dr. Benjamin Baiser and Dr. Christina Romagosa and belong to both The Baiser Lab and The Florida Invasion Ecology Lab within the Wildlife Ecology and Conservation Department at the University of Florida
What is your over-arching research topic?
Impacts of invasive species on the structure and function of native food-webs.
What Simberloff publication is most inspiring to you and why?
Simberloff, D., 2006. Invasional meltdown 6 years later: important phenomenon, unfortunate metaphor, or both?. Ecology Letters, 9(8), pp.912-919.
In this publication Simberloff revisits his concept of invasional meltdown and the idea that introduced species could facilitate one another’s invasion success to novel environments where he further clarifies the concept, explores the evidence uncovered for meltdown since the original paper (Simberloff & Von Holle, 1999), and addresses the utility of the metaphor in understanding the phenomenon. I found this inspiring because it highlights the generative nature of science and how we are always building from past research and ideas. Additionally, for my own research, the concept of invasional meltdown inspires future questions, utilizing ENA and integrating multiple invaders to determine how they impact not only each other but if they have a compounding effect on shifting overall ecosystem structure and function.
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Peter Lutz, University of Minnesota - Twin Cities
Briefly describe your project’s background/question/methods:
How species can coexist despite antagonistic biotic interactions within an environment is fundamental to understanding biodiversity. Mutualistic interactions can act as a mechanism driving coexistence between competing species. In a mutualism, dependence is the factor of population growth attributed to a partner. We constructed a spatial model of three interacting species and simulated generations of growth and dispersal to better understand how differential dependence on a shared mutualist partner influences the ranges and coexistence of two competing species coinvading a new landscape.
Briefly describe your project’s results/conclusions:
We found that in co-invasions of a new habitat, differential mutualism dependence and competitive ability can generate both local and regional coexistence. Greater dependence on a mutualist partner is a mechanism that can enable a weaker coinvading competitor to coexist with a stronger one, but the advantages of high dependence diminish when competition is stronger. Finally, we observed that the more mutualist-dependent species dominates at the range edges when competition is weak, but is excluded from the range edges when competition is strong.
What department and university do you belong to?
Department of Ecology, Evolution and Behavior at the University of Minnesota - Twin Cities, College of Biological Sciences
What is your major and year of study at your university?
I'm currently a senior majoring in Ecology, Evolution and Behavior.
Do you belong to a lab? If so please list.
I've been working on this project in Dr. Allison Shaw's lab, with PhD candidate Naven Narayanan.
What is your over-arching research topic?
I'm interested in using theoretical approaches such as simulation models to study how species interactions, particularly mutualisms, impact invasion dynamics.
What Simberloff publication is most inspiring to you and why?
Simberloff & Von Holle 1999 "Positive interactions of nonindigenous species: invasional meltdown?" is an inspiration because it demonstrates how presenting an overlooked phenomenon in an intuitive way can have such a large impact on future research.
Award Winners 2022:
We are pleased to congratulate Taylor Zallek and Kay Strain for their outstanding oral and poster presentations, respectively. Below is some information that Taylor and Kay shared about their research and their favorite Simberloff publication:
Taylor Zallek, best oral presentation
Presentation Title: Evolution in response to management and propagule size interact to increase invasiveness among experimental populations of aquatic plants
Taylor is a PhD candidate in Ecology and Evolution. He is in Dr. Martin Turcotte's lab in the Department of Biological Sciences at the University of Pittsburgh. Taylor is generally interested in the relative influence of ecological and evolutionary factors on invasion success or failure; specifically, he is studying how invasion removal efforts may influence the course of an invasive population's evolution. His experiments simulated repeated reductions in genetically diverse populations of the duckweed Lemna minor and subsequent introductions to other communities of duckweed species. He was then able to compare invasiveness in populations that had evolved under repeated removal events versus no simulated invasion management. Taylor found that duckweed populations experiencing multiple management events had evolved to become more invasive, with higher population growth and biomass. He concludes that "these results seem to demonstrate that the long-term eco-evolutionary consequences of certain management practices can be complicated and potentially detrimental towards ultimate conservation goals".
Most inspiring Simberloff publication: Positive interactions of nonindigenous species: invasional meltdown? (Simberloff and Von Holle, 1999)
Taylor says: This paper and the concept of invasional meltdowns provided the framework for my very first experience conducting research as an undergraduate student at St. John’s University in central Minnesota. We measured the potential synergistic effects of invasive understory shrubs and earthworms in deciduous forests. This paper, and the experience that accompanied it, made me curious about the multitude of factors that influence invasions and sent me on a journey that I continue to pursue to this day!
Kay Strain, best poster presentation
Presentation Title: Cheatgrass (Bromus tectorum) modifies the soil microbial community
Kay is a fourth year PhD candidate in Ecology, Evolution, and Conservation in the Department of Natural Resources at the University of Nevada, Reno. As a member of Dr. Erin Hanan’s Fire and Dryland Ecosystems lab, they study the interactions among drought, wildfires, and grass invasions and how they influence nutrient cycling and retention in drylands. Their research investigates whether drought stress stimulates root exudation in cheatgrass, which in turn spurs microbes in the rhizosphere to increase soil organic matter decomposition, leading to more N mineralization. They simulated drought in a greenhouse experiment with invasive cheatgrass, extracting root exudates and measuring soil microbial function and biogeochemical cycling. Although cheatgrass did increase N availability, the mechanism seemed to be through suppression of heterotrophic microbes via root exudates instead of stimulating microbes as originally expected. Kay concludes that "by reducing heterotrophic microbial biomass, root exudation by cheatgrass likely released nitrifiers and plant roots from competition for ammonium, increasing N availability in the rhizosphere".
Most inspiring Simberloff publication: Experimental zoogeography of islands: the colonization of empty islands (Simberloff and Wilson 1969)
Kay says: [It] is inspiring to me because it speaks to his qualities as a creative and critical thinker. His inventive approach to research design and commitment to challenging and strengthening our understanding of ecology have led to impactful and innovative research over the course of his career.
In his dissertation research, his meticulous care to testing dynamics of colonization allowed him to put theory to the test. While this work appeared to be painstaking, his dedication to the problem at hand was clear. To me, this serves as a reminder that while assessing ecological theory and challenging norms can be difficult and risky, it is worthwhile research. Additionally, in his discussion of colonization dynamics in his paper Experimental zoogeography of islands: the colonization of empty islands, you can see the seeds of some of his later work. I find it stirring to see Simberloff’s thinking when he was at a similar career stage to where I am now, and how he developed these ideas later in his career. While some ideas may take years to fully mature, they are still worth the investment. His approach to fully testing and understanding ecological concepts is inspirational - I hope that throughout my career, I too can face challenging problems with similar creativity, determination, and patience.
References:
Simberloff DS, Von Holle B (1999) Positive interactions of nonindigenous species: invasional meltdown?. Biol Invasions,1: 21-32
Simberloff DS, Wilson EO (1969) Experimental zoogeography of islands: the colonization of empty islands. Ecology, 50: 278-296
Award Winners 2021
Angela Walcyzk for her presentation entitled: “Investigating phenotypic plasticity in biological invasions and implications for the invasive success of tetraploid Solidago gigantea (Giant Goldenrod, Asteraceae).”
Background/Question/Methods:
Biological invasions are a global ecological and socio-economical threat. It has been hypothesized that relative to native species, invasive species exhibit increased phenotypic plasticity (PP) and tolerances in response to a wider range of environmental conditions; increased PP is thought to contribute to invader success. However, empirical support that invasive species/populations exhibit increased PP relative to related non-invasive species/populations or that increased PP confers fitness advantages that could be selectively favored are rare. In this study we examined whether invasive forms have higher PP relative to non-invasive forms, whether PP is associated with increased fitness, and whether pre-adaption or post-introduction selection influences PP of traits associated with biological invasions. To address these questions, we grew native and invasive genotypes of tetraploid Solidago gigantea in a controlled field experiment with low, medium, and high soil nitrogen and phosphorus availability and measured five growth traits (above- and belowground biomass, root/shoot ratio, height, clonal shoot production), three physiological traits (photosynthetic capacity, transpiration rate, water use efficiency), and two defensive traits (foliar terpene concentrations, herbivore damage). We chose to vary these nutrients because invasive species tend to colonize in nitrogen and phosphorus altered areas.
Results/Conclusions:
Both native and invasive genotypes experienced gains in biomass, height, clonal shoots, and photosynthetic capacity as nutrients increased. However contrary to our expectations, native genotypes displayed more PP to the nutrient environment in terms of above- and belowground biomass accumulation and height and also had greater mean values for these traits than invasive genotypes. Both invasive and native genotypes displayed similar PP responses and mean values for clonal shoot production and root/shoot ratios. PP for physiological traits was similar between genotypes, but invasive genotypes displayed greater photosynthetic capacity and transpiration rates but less water use efficiency. Analyses of defensive traits are pending. These preliminary results do not support our original hypotheses and suggest that PP in invasive tetraploid populations of S. gigantea might have been reduced by genetic drift and/or by selection for specific trait values that are better adapted to invasive habitats. This study is one of the few controlling for the potential effects that polyploidy might have on PP by comparing only native and invasive populations of the same ploidy level. Additional studies in this system are needed to explicitly test the influence of polyploidy on PP and to better understand why only tetraploid S. gigantea became invasive.
What is your year of study at your university?
I am in the third year of my PhD.
What lab do you belong to?
I belong to the Hersch-Green Lab within the Department of Biological Sciences at Michigan Technological University.
What is your over-arching research topic?
I am studying how polyploidy influences plant responses to the biotic and abiotic environment. Specifically, I am testing whether higher ploidy levels have increased nutrient demands and if these increased demands lead to trade offs that aren't present in lower ploidy levels. I am also investigating the role of polyploidy in biological invasions by comparing the trait and gene expression responses of native and invasive populations of the same ploidy level to abiotic stressors.
What Simberloff publication is most inspiring to you and why?
Genovesi, P. and Simberloff D. (2020). “De-extinction” inconservation: Assessingrisksofreleasing“ resurrected” species. Journal for Nature Conservation. 56:125838. I was introduced to the topic of "de-extinction" in a Conservation Biology class, and since then I have found its proposal as an innovative conservation tool to be both fascinating and concerning. In this paper, Genovesi and Simberloff clearly discuss the risks and potential benefits of introducing extinct species proxies into modern ecosystems through the lens of invasive biology. I personally like this publication because its incorporation of conservation biology, policy making, and public opinion make for a fantastic springboard into complex ecological discussions. For that reason, I feel that this publication is a strong learning tool that can enhance classroom discussions and students' understanding of ecology and biology.
Will Pfadenhauer for his presentation entitled: "Identifying the biogeographic traits of invasive plants’ native habitats.”
Background/Question/Methods
Reducing ecological threats from invasive plants is most effective if we proactively identify invasive species and stop their introduction and spread. Risk assessments, which identify potentially invasive plants, typically focus on biological traits (e.g., growth rates, dispersal capability). However, the environmental characteristics of invasive plants’ native habitats (termed “biogeographic traits”) may also provide important clues about invasion risk. Biogeographic traits may reflect species environmental tolerance and competitive ability - traits that are difficult to measure based solely on biology. Here, we compiled biogeographic variables associated with the native habitats of 5,500 vascular plant species native to the continental United States (CONUS). We categorized each species’ invasion status outside of CONUS as “native”, “established”, or “invasive” based on information from existing databases (USDA Plants, CABI, GRIIS, GloNAF, and Global Plant Invaders). We hypothesized that species with broader abiotic niches in the native habitat and species more accessible to human discovery (e.g., proximal to human footprint) would be more likely to establish and invade outside of the U.S. To test these hypotheses, we used logistic regressions and support vector machines to assess the significance and accuracy of biogeographic traits for predicting invasion status.
Results/Conclusions
Our results suggest that species with broader abiotic niches are more likely to become established and invasive. We found that the range of temperature, precipitation, soil pH, and soil texture in a species’ native habitat had the strongest predictive power for explaining the likelihood of both establishment and invasion. Models that incorporated these variables correctly predicted the invasion status for ~72% of plant species and explained more variation than models that used combinations of other biogeographic traits. While we found some support for our second hypothesis - human footprint variables were positively correlated with invasiveness - these variables did not offer as much predictive power as variables describing niche breadth. The support for our hypotheses suggests that invasive plants have higher physiological tolerances than both native and established species, supporting the inclusion of niche breadth variables in invasive plant risk assessments. Our results also suggest that accessibility to humans increases the likelihood that a species will be established elsewhere. However, variables representing human footprint did not help to distinguish established species from invasive species, suggesting these traits may not be useful for risk assessments.
What is your year of study at your university?
I am just beginning my second year at the University of Massachusetts Amherst.
What lab do you belong to?
I am a part of the Spatial Ecology Lab, which is led by Dr. Bethany Bradley.
What is your over-arching research topic?
I am particularly interested in analyzing big data with spatial and statistical techniques to study global trends in plant invasions. Much of my current work is also aimed at evaluating existing management practices for invasive plants or otherwise generating actionable information for managers and policymakers.
What Simberloff publication is most inspiring to you and why?
This is a tough choice, but I'd have to say "Ecological Resistance To Biological Invasion Overwhelmed By Propagule Pressure" by Von Holle and Simberloff (2005). I'm currently working on a project that evaluates the different pathways used by invasive plants to relocate to new environments, so these days I'm thinking a lot about propagule pressure, how it interacts with other variables, and the role it plays in the different phases of the invasion process. This publication clearly conveys the importance of propagule pressure in determining invisibility, and in doing so inspires me to better understand these underlying processes and help create more effective invasive plant management strategies in the future.
Award Winners 2020
Rebecca Mostow for her oral presentation titled "Discovery of a novel, dune-building grass: Hybridization of non-native beachgrasses (Ammophila arenaria × breviligulata) along the U.S. Pacific Northwest coast”
What is your year of study at your university? What lab do you belong to?
I am a 5th year PhD candidate working with Dr. Sally Hacker at Oregon State University.
What is your over-arching research topic?
I study the ecology and population genetics of two invasive, closely-related, dune-building beachgrasses. These two grasses densely invaded the US Pacific Coast leading to habitat loss for native flora and fauna but also dramatically increasing the coastal protection provided by dunes to nearby towns and cities. The discovery of a novel hybrid between the two species (as described in my ESA talk) has pushed me to complete a truly interdisciplinary PhD, integrating genomic tools with models and theory from invasion ecology.
What Simberloff publication is most inspiring to you and why?
Rhymer, J. M., and D. Simberloff. 1996. Extinction by Hybridization and Introgression. Annual Review of Ecology and Systematics 27:83–109. Although it is hard to pick just one Simberloff paper, I think I have to go with "Extinction by Hybridization and Introgression." I became fascinated with invasive plants during a year working on plant conservation in the Great Basin. Every day I saw the immense ecological consequences of biological invasions and decided to go to grad school to study evolution in invasive plants, hoping to understand how these organisms were able to thrive in environments in which they did not originally evolve. This paper opened my eyes to the potential impact of hybridization, introgression, and gene flow between the species in my study system and helped me to understand the potential implications of our recent discovery. Additionally, as someone interested in science communication, I have always admired the clear, thorough, and well-reasoned style with which Dr. Simberloff always writes, this being no exception.
Evelyn “Eve” Beaury for her oral presentation titled "Invaders for sale: The ongoing spread of invasive species by the plant trade industry"
What is your year of study at your university? What lab do you belong to?
I am beginning my fourth year of my PhD in Organismic and Evolutionary Biology at the University of Massachusetts Amherst. I am part of Dr. Bethany Bradley's spatial ecology lab.
What is your over-arching research topic?
I study the macroecology and biogeography of invasive plant presence, abundance, and impact. I'm particularly interested in research that intersects invasive species' ecology, policy, and management, as well as interactions between invasive species and global change.
What Simberloff publication is most inspiring to you and why?
It is hard to choose just one, but I'm currently most inspired by Simberloff D, Parker IM, Windle PN (2005) Introduced species policy, management, and future research needs. Frontiers in Ecology and the Environment 3:12–20. This study reviews major issues in invasive species research, policy, and management, as well as advocates for why these three domains need to be better integrated. I am inspired by this review because I am most passionate about projects that connect science to real-world problems. Although published 15 years ago, Simberloff et al. 2005 highlights a disconnect between research and implementation that is still prevalent today and which is exemplified by the work on ornamental invasive plants that I presented at ESA. This publication, and many others by Simberloff, motivates me to work on projects that impact the way we study and manage invasions in the United States.
Award Winners 2019 (this opens in a new tab)
Please join us in congratulating Emily Kiehnau and Patrick Milligan for their outstanding oral presentations at the 2019 Ecological Society of America’s Annual Meeting in Louisville, Kentucky, USA. We asked Emily and Patrick to share a little bit about themselves, their research, and their favorite publication authored by Dan Simberloff. Read more (this opens in a new tab)
Emily Kiehnau
Patrick Milligan
Award Winners 2018 (this opens in a new tab)
We are pleased to announce the inaugural recipients of the Simberloff Award for Outstanding Presentation: Carmela Buono and Amanda Carr for their outstanding poster (Buono) and oral (Carr) presentations. Read more (this opens in a new tab)
Carmela Buono
Amanda Carr
Daniel Simberloff
Daniel Simberloff is the Gore Hunger Professor of Environmental Studies at the University of Tennessee Knoxville and the Editor-in-Chief of the journal Biological Invasions. He is a world-renowned scholar who earned his PhD at Harvard where he provided the first experimental test of MacArthur and Wilson’s theory of Island Biogeography. He has authored over 400 peer-reviewed papers on ecology, biogeography, evolution, conservation biology, ecosystem management, and biological invasions. Multiple generations of students have learned from him; his work is mentioned in every modern textbook in ecology and conservation biology, and he has been at the forefront of some of the most vigorous debates in the history of these fields including invasion science. He was a recipient of the Eminent Ecologist Award by the Ecological Society of America in 2006, elected to the U.S. National Academy of Sciences in 2012, awarded the Ramon Margalef Prize in Ecology in 2012 and the Wallace Prize of the International Biogeographical Society in 2015.