Browsing by Subject "Invasive Species"

Now showing 1 - 12 of 12

CFANS Semester Study Abroad in Nepal
(University of Minnesota Tourism Center, 2014) Brouellette, Lisa; Flynn, Mike; Folsom, Paul; Hill, Alicia; Nichols, Leiloni; Seaman, Kristin; Shine, Logan
Climate Change and Tallgrass Prairies: Exploring the Interaction of Extreme Weather and Invasion in Managed Prairie Systems
(2020-12) Ratcliffe, Hugh
Climate change will increasingly shift seasonal timing and increase the frequency and intensity of extreme events like drought and severe wet conditions, all of which threaten to amplify other global change drivers like invasion. Consequently, understanding how conservation management actions like prescribed burning interact with climate is increasingly pressing for invasive management. Although prescribed burning has been widely demonstrated to increase native plant diversity and suppress a number of invasive species, understanding under what current and future conditions burning will be most effective remains an ongoing focus of applied prairie ecology research. Earlier springs and extended growing seasons will shift the timing and availability of resources and niche space, which may disproportionately advantage invasive species and also influence the outcome of burning. Furthermore, northern tallgrass prairies will experience intensified extreme precipitation patterns characterized by more precipitation falling in fewer events interspersed with longer dry periods and amplified evapotranspiration. Because moisture availability functions as a key determinant of prairie composition, theory and evidence suggest drought conditions will hinder invasion, whereas wetter conditions will enhance invasion. Here, I conducted two analyses exploring the effect of weather on prairie invasion dynamics from 2010-2019 in 25 observed prairie sites and 267 transects spread throughout Minnesota, USA. First, I estimated the effects of burning, start time of the growing season, and their interaction. Second, I estimated how an increase in extremely wet or dry months altered invasive abundance and influenced the effectiveness of burning. For the first analysis, I determined that burning reduced both total invasive and invasive cool season grass abundance, and that this reduction persisted over time for invasive cover but quickly waned for frequency. Additionally, I found that growing season start does indeed influence community composition but that later starts rather than earlier increased invasive abundance. For the second analysis, I found that a greater occurrence of abnormally wet months increased invasive abundance and minimal evidence that abnormally dry conditions hinder invasion. Furthermore, I did not observe additive interaction effects of drought and prescribed burning but did find that an increase in the number of wet months reduced the effectiveness of burning. Together, these results suggest that, although earlier spring timing is unlikely to be a primary mechanism driving increased invasion, more frequent extremely wet and dry months may intensify invasive dominance and hinder our ability to suppress invasion species via prescribed burning. Ultimately, I propose that future research should seek to better understand abiotic controls on invasive species’ phenologies, how precipitation seasonality influences invasive performance, and also identify potential thresholds in ecological processes to understand whether responses in community invasion dynamics are abrupt or gradual.
The ecology and evolution of an invasive perennial plant (Lythrum salicaria) in the context of biological control by specialist herbivores (Galerucella spp.)
(2013-09) Quiram, Gina Louise
The introduction of non-native species to novel ranges has provided biologists the opportunity to study organisms experiencing sudden and sustained shifts in community composition and selection pressure. Management programs for invasive species can result in similar shifts. In classical biological control programs, non-native species are introduced to control invasive species. The short-term impacts of these introductions on invaded communities are often well documented, but the long-term impacts on the ecology and evolution of target invasive species are not well understood. Using a combination of field surveys, common garden techniques, and quantitative genetic models, I examined the effect of biological control by specialist herbivores (Galerucella spp.) on purple loosestrife (Lythrum salicaria L.) in southern Minnesota (MN), USA. Chapter 1 describes field surveys completed to determine the extent to which biological control directly reduces plant vigor, competitive performance, and reproduction. In Chapter 2, I quantify the extent to which population level variation in vigor, competitive performance, herbivore defense, and herbivore tolerance of L. salicaria reflects an evolutionary divergence following the introduction of biological agents. Finally, in Chapter 3 I assess the potential for L. salicaria to evolve in response to continued selection pressure. The results of these studies show that Galerucella spp. biocontrol agents remain established and continue to feed on L. salicaria in southern MN, but do not universally reduce the vigor, competitive performance, or reproduction of the plant in field populations as compared to populations lacking established populations of biocontrol agents. When grown in a common environment, an experimental garden, populations of L. salicaria having experienced herbivory by Galerucella spp. for 16 years are more vigorous, marginally more competitive, and marginally more tolerant of herbivory compared to populations lacking a historical association with the herbivore. In MN, L. salicaria is currently under selection pressure for increased vigor, and the plant has the genetic capacity to adapt in response to this selection pressure. Further evolution of L. salicaria could decrease the effectiveness of biological control by Galerucella spp.
Effects of bluegill predation, lake productivity, and juvenile dispersal on common carp recruitment dynamics in lake-marsh systems in Minnesota
(2016-02) Lechelt, Joseph
Processes that regulate common carp (Cyprinus carpio) recruitment (i.e. survival of eggs, larvae and juveniles) are largely unknown. In interconnected lake-marsh systems of Minnesota, young of year (YOY) carp are generally found in marshes that winterkill and lack bluegill sunfish (Lepomis macrochirus), an abundant native predator. This suggests that bluegills might function as a biocontrol agent for carp. Further, whereas YOY carp are commonly found in winterkill marshes of south-central Minnesota, they are not found in similar systems in northern Minnesota where lake productivity is much lower, suggesting an aquatic productivity bottleneck on carp recruitment. Finally, in marshes where carp recruit (productive and bluegill-free), YOY must disperse into adjacent lakes to drive high population abundance. In this study, I conducted three experiments to test 1) the effect of bluegills on carp recruitment; 2) the effect of aquatic productivity on larval carp survival, growth and diet; 3) natural dispersal tendencies of YOY carp from a marsh into an adjacent lake. The first experiment employed four (20 m diameter) impermeable enclosures from 2011-2014. Each year, enclosures were stocked with carp eggs and every other one was stocked with bluegills. Backpack electrofishing surveys conducted five weeks later showed that carp catch per unit of effort (CPUE) was over 10-fold lower in the enclosures stocked with bluegills than in the controls. The second experiment, conducted in 2014 and 2015 used aquaria stocked with carp larvae and supplied with zooplankton densities and community structures from lakes of three different trophic states (oligo-, meso-, and eutrophic). It showed that carp larvae selectively consumed macrozooplankton (> 200 μm) and their growth rates were highest in the eutrophic lake and lowest in the oligotrophic lake. Survival, however, was high in all treatments. The third study was conducted in a natural lake-marsh system and utilized passive integrated transponder (PIT) tags to quantify the outmigration of YOY carp from the marsh to the lake. It showed that < 6% YOY carp outmigrated to the lake, supporting previous indirect estimates. The results of these three studies are important to understanding recruitment dynamics of carp in lake-marsh systems in Minnesota.
Emerald Ash Borer as a Constraint to Recreation? Interviews with Visitors to Two Minnesota State Parks
(University of Minnesota Tourism Center, 2014) Schneider, Ingrid; Schlueter, Alex; Matter, Katie; Arnberger, Arne; Venette, Robert; Snyder, Stephanie; Cottrell, Staurt
The purpose of this study was to understand visitor perceptions of EAB’s visual impacts & if EAB acts as a constraint to recreation.
Minnesota Tourism Industry Perceptions of Invasive Species and Their Control
(University of Minnesota Tourism Center, 2014) Schneider, Ingrid E.; Qian, Xinyi
A 2013 questionnaire of the Minnesota tourism industry, in partnership with Explore Minnesota Tourism (EMT), assessed perceptions about invasive plants and aquatic invasive species and their control.
Perceptions of Invasive Species and Their Control Among the MN Tourism Industry
(University of Minnesota Tourism Center, 2014) Schneider, Ingrid E.; Qian, Xinyi
This project sought baseline information on perceptions of invasive species and theie control among the Minnesota tourism industry. The majority of respondents agreed that both invasive plant & aquatic invasives were harmful to Minnesota’s environment, economy & society. Similarly, the majority of respondents indicated all 7 control methods presented in the questionnaire would be effective to control invasive species.
Potential host use by the Mediterranean Pine Engraver on Novel Tree Species.
(2009-05) Walter, Abigail Jan
Introduced species have the potential to cause great environmental damage, but many species introduced to an area will not have a large impact. It is critical that we develop the ability to predict which species will become damaging invaders, and manage ecosystems to minimize the probability that introduced species could establish. I present research results on the potential of the Mediterranean pine engraver, Orthotomicus erosus (Wollaston), to utilize North American tree species as hosts. I confirm that several North American conifers, species of pine and spruce, are suitable for the development of O. erosus. I then investigate the host acceptance behaviors of adults in contact with the outer bark. I show that differences among species occur during boring into the outer bark, and that beetles bore into both suitable and unsuitable tree species. The behavior of beetles before they are in contact with the bark was investigated with an olfactometer; odors from several conifer species do not affect the behavior of adult beetles. I also test the feeding response of beetles to extracts of bark and phloem chemicals. Several extracts contain feeding incitant or stimulant compounds, but the presence of these compounds in various tree species is different than adult bark boring behavior on those species. Finally, I used the data from my previous experiments and the phylogenetic distance among tree species in an attempt to predict the response of O. erosus to a second set of tree species from independent validation experiments. Phylogenetic distance from species with known beetle responses was not a good predictor of beetle response to novel plants. This body of work shows that O. erosus may accept a larger set of trees than are suitable for reproduction. Furthermore, adult host acceptance behavior is not determined solely by gustatory stimuli. Detailed knowledge about the stimuli governing host acceptance behavior is needed to predict the acceptability of new tree species to the beetle. The presence of acceptable but developmentaly unsuitable plants may determine whether species such as O. erosus are able to establish in a new environment.
A Risk-Release Assessment Of Aquatic Invasive Species Using Protist Surrogates In Mesocosm Studies
(2024-04) Latanich, Abigail
Untreated ballast water discharge is considered responsible for nearly thirty percent of aquatic invasive species (AIS) introductions in the Laurentian Great Lakes. Currently, the ballast discharge standard for organisms between 10 and 50 µm in size is 10 cells/mL, implying introductions of live protists below this density in released ballast water are allowable. However, data are lacking on protist risk-release relationships; i.e., the level of propagule pressure that results in non-native species establishment. This research investigates the risk-release relationships for various non-native protist taxa under varying water conditions using mesocosms. To mimic ballast discharge events, protist densities of 0 - 100 cells/mL were inoculated into mesocosms filled with Duluth-Superior Harbor (western Lake Superior) water and sampled over 4 weeks. Experiments evaluated four surrogate “invaders”: Haematococcus pluvialis, Trachelomonas abrupta, Chrysosphaerella sp., and Melosira varians. Logistic models predicted the minimum surrogate protist densities resulting in establishment ranged from 11 to 127 cells/mL for non-native species, thereby providing information on risk-release relationships relative to the discharge standard. We also noted how seasonality (e.g., varying ambient water conditions) influences establishment success. Though there are limitations of the mesocosm method in invasive species studies, our successful application of mesocosms to study non-native, risk-release relationships supports the potential use of this method in other locations (e.g., other harbors, ports) and with additional taxa.
Species Distribution Models and Joint Species Distribution Models of Nine Invasive Species in North America
(2019-08-27) Lake, Thomas, A; Briscoe Runquist, Ryan, D; Moeller, David, A; rbriscoe@umn.edu; Briscoe Runquist, Ryan, D; Moeller Lab
Species Distribution Models (SDM) and Joint Species Distribution Models (JSDM) for nine invasive species in North America. Species SDMs include Brown Knapweed (Centaurea jacea), Black Swallowwort (Cynanchum louiseae), Common Tansy (Tanacetum vulgare), Common Teasel (Dipsacus fullonum), Wild Parsnip (Pastinaca sativa), and Dalmatian Toadflax (Linaria dalmatica). Species JSDMs include Japanese Hops (Humulus japonicus), Oriental Bittersweet (Celastrus orbiculatus), and Narrowleaf Bittercress (Cardamine impatiens). These models aim to predict the current and future habitat suitability of nine invasive species in North America. Models were constructed with the MaxEnt software. Predicting current and future habitat suitability for invasive species may help manage invasions.
Studies of the round goby (Neogobius melanostomus) population of the St. Louis River Estuary
(2013-12) Leino, Jared
This thesis consists of multiple chapters/studies including a review chapter (chapter 1), and two additional studies of which have abstracts that are embedded in the thesis.
A study of herbaceous vegetation in Chequamegon - Nicolet National Forest: relationship of earthworms, white-tailed deer browsing and Carex pensylvanica Lam
(2014-12) Ojanen, Paul Thomas
Invasive earthworms alter multiple forest components. By accelerating litter decomposition, they alter nutrient flows, soil composition and vegetative communities. White -tailed Deer (Odocoileus virginianus) are known to alter vegetative communities by selective browsing; severity varies with population density and affects plant community population and composition. Both factors are associated with reduced vegetative community richness and dominance by graminoids. In this study, 101 randomly selected Northern Mesic Hardwood Sugar Maple sites in the Chequamegon - Nicolet National Forest were sampled for vegetation, earthworm occurrence and browsing intensity. Over three years, eighty-two percent of sites were positive for earthworms; in two non-drought years, ninety percent of sites were positive. Non-metric Multi-dimensional Scaling (NMDS) and Multiple Response Permutation Procedure (MRPP) found divergent communities; a Carex pensylvanica Lam dominated community associated with earthworm invasion and strongly linked to Lumbricus rubellus presence, and remaining Acer saccharum seedling stands associated with reduced earthworm impacts. Additionally Carex pensylvanica was strongly linked to Lumbricus rubellus presence by Indicator Species Analysis. Lumbricus rubellus invaded sites had both reduced species richness and vegetative cover. White-tailed deer (Odocoileus virginianus) browsing was found to be heavy and extensive throughout both forests, impacting Acer saccharum regeneration and further driving graminoid dominance. The results indicate earthworm invasion is geographically extensive and a principal driver of Carex pensylvanica understory dominance and reduced Acer saccharum regeneration.

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