Invasive plants can displace native species, deteriorate native forest, and change plant communities and ecosystem functions. Native plant populations are fundamentally impacted by invasive species because of the interactions between invasive species and native plants. This study focuses on understanding the extent, mechanisms and consequences of interaction between a non-indigenous invader Ailanthus altissima and its functionally similar native species Robinia pseudoacacia in the Mid-Appalachian region, from an individual scale to a regional scale. These two subject species are common and coexist in early-successional eastern deciduous forest. The interactions between these two common species are important to community structure and canopy tree regeneration. To address the type and extent of interactions of these two species, a greenhouse experiment utilizing various species proportions, nutrient levels and seed sources was performed. In addition, a common-garden experiment with various species densities and proportions over three consecutive growing seasons was performed in a more natural condition than that of the greenhouse experiment. We found at the seedling stage, the dominant interaction was competition, and R. pseudoacacia was the winner both above- and belowground. The allelopathic compounds of A. altissima may have inhibited nodulation of R. pseudoacacia. Ailanthus altissima seedlings from its native region had slightly stronger competitive abilities compared with the seedlings from its invaded range. In the common garden experiment, R. pseudoacacia plants grew quicker than A. altissima, but A. altissima inhibited the growth of R. pseudoacacia by interspecific competition. The negative impact of A. altissima on R. pseudoacacia became larger as time progressed. To assess the community-level consequences of the two species, we conducted a forest mapping and a complete target-tree-based forest survey, and analyzed regional-scale data from the Forest Inventory Analysis Data Base. The two target species were significantly associated with themselves and with each other. Community species composition and diversity were significantly different across sites. A negative impact of both species on the understory community diversity and tree regeneration at the neighborhood scale was detected; while at a regional level, tree diversity in the FIA plots with either A. altissima or R. pseudoacacia was higher than the reference plots. / Ph. D.

The increasing scope and speed of biological invasions around the world is a major concern of the modern environmental conservation movement. Although many ecological impacts of biological invasions are still not well understood, there is a general consensus that exotic, invasive species are a primary driver of extinctions globally. By altering ecosystem structure and function, invasive species also affect human quality of life; however, not all impacts lead to negative outcomes. Given that invasive species have diverse impacts on society, their management in human-dominated landscapes is a wicked problem wherein the resolution is as much an issue of social value as technical capacity. The purpose of my research was to understand the propensity for engaging private landowners in an effort to eradicate an invasive species on an inhabited island. Specifically, I investigated private landowner perspectives on eradicating the North American beaver (Castor canadensis) from the Tierra del Fuego (TDF) island archipelago in Argentina and Chile. The beaver was introduced in 1946 and has since become a central conservation issue due to its long-lasting changes to local hydrology, nutrient cycling, riparian vegetation, food webs, and aquatic and terrestrial species assemblages. Because eradication requires near complete cooperation from stakeholders and no research had been conducted to understand the perspectives or willingness of private landowners to cooperate, my objectives were to: 1) characterize the links private landowners make between the presence of beavers and impacts to the ecosystem services in their riparian areas, and 2) explore the role of a market-based incentive program to increase landowner cooperation in eradication efforts. Through semi-structured interviews, I elicited landowner mental models of how beavers impact the ecosystem services they receive from their riparian lands. I found that TDF ranchers prioritized provisioning ecosystem services, and held diverse and idiosyncratic beliefs about how beavers influence these outcomes. TDF ranchers may not recognize the beaver as a highly salient problem because they do not connect them to reductions in ecosystem services that are important to them. Among those who do perceive beavers affecting important ecosystem services, there is no clear, unified understanding of how the beavers disturb the ecosystem and key ecosystem services. Additionally, in a broadly administered survey, I used a factorial vignettes to examine the role of program structure and other program-related factors on landowners' willingness to participate in a voluntary eradication program. Overall, landowners were willing to cooperate in an incentive program to eradicate beavers. They were positively motivated by greater financial compensation, an increased expectation that the program would be successful, and the program assuming full responsibility for its implementation. Other factors returned mixed results indicating that further research may be required. In diverse, human-inhabited, and privately-owned landscapes, conservation requires collective action—i.e., the high threshold of participation needed for eradication to be achieved. Understanding the knowledge systems that cause landowners to perceive value or risk serves as a first step in understanding behaviors, and can also serve as a framework for crafting more effective outreach, as current communication about the beaver and the proposed eradication may not resonate with private landowners. Further, barriers to inaction can be overcome by understanding landowner needs and how program-related factors influence the potential for cooperation. In sum, by putting human needs at the forefront of program design, conservation planners can better understand stakeholder perspectives, reduce barriers to participation, and ultimately increase cooperation and improve conservation outcomes. / Master of Science

<p dir="ltr">Using historic acoustic bat data collected by the Indiana Department of Natural Resources, we constructed Bayesian occupancy models to gain insights into bat communities and populations across Indiana. Through use of informative prior distributions, we addressed two important considerations for bat conservation with our occupancy models: 1) exploring a compensatory community dynamic causing the expansion of evening bat (<i>Nycticeius humeralis</i>) populations in Indiana following the establishment of white-nose syndrome (WNS), and 2) estimating a percent decline of summertime hoary bat (<i>Lasiurus cinereus</i>) populations in Indiana due to wind energy development. We found evidence for a potential compensatory community dynamic in the evening bat system, in which losses of the Indiana bat (<i>Myotis sodalis</i>) and the little brown bat (<i>Myotis lucifugus</i>) due to WNS may be resulting in new realized niche space for evening bats, thereby contributing to a compensatory community dynamic. In our hoary bat system, we found evidence of a regional summertime decline of 8.9% annually since 2012. These findings have important conservation implications considering imperiled nature and conservation priorities for bats in North America. </p>

Many municipalities around Sweden use public access spatial data from Artportalen to track and fight invasive species, but anyone can upload data to Artportalen and not all of it becomes verified. They could potentially enhance their efforts by incorporating street view technology for more reliable data. One municipality that uses Artportalen data is Jönköping, which suffers from Reynoutria japonica. I randomly selected 50 areas around Jönköping with reports of R. japonica and went through them using Street View. The purpose of this study is to test if Street View can be used to improve the reliability of Artportalen data and if it can fully replace other methods to do so. I counted each individual of R. japonica I could identify and compared it to the number of reports in each area. Among the 50 areas only 26 were reachable in Google Street View and some plants were impossible to identify if they were R. japonica or not. When looking at the areas that could be reached it showed no difference between Reports in Artportalen and what was found in Street View if you included the unidentifiable plants. When excluding unidentified plants or when including areas that could not be reached it showed a significant difference. Using Google Street View to complement Artportalen data for R. japonica comes with benefits and limitations. Many areas were impossible to reach, but where accessible, it proved effective in identifying misreports and finding unreported plants without the need to visit the location. Street View data can enhance the reliability of distribution data used for monitoring invasive species without ever needing to travel, however it cannot fully replace other methods of enhancement and for the best reliability, a combination of Street View and on-site visits is necessary. / Många kommuner runt om i Sverige använder offentligt tillgängliga geodata från Artportalen för att spåra och bekämpa invasiva arter, men vem som helst kan ladda upp data till Artportalen och inte all data blir verifierad. Kommunerna skulle potentiellt kunna förbättra sina insatser genom att använda Street View teknologi för att få mer tillförlitliga data. En kommun som använder sig av data från Artportalen är Jönköping, som lider av den invasiva växten Reynoutria japonica. Syftet med den här rapporten är att testa om Street View kan användas för att komplimentera data från Artportalen och om det kan helt byta ut andra metoder att göra samma sak. Jag valde slumpmässigt ut 50 områden runt Jönköping med rapporter om R. japonica och gick igenom dem med Street View. Jag räknade varje individ av R. japonica jag kunde identifiera och jämförde det med antalet rapporter i varje område. Bland de 50 områdena var det bara 26 som kunde nås med Google Street View och vissa växter var omöjliga att identifiera om de var R. japonica eller inte. När man tittade på de områden som kunde nås visade det ingen skillnad i antal växter mellan rapporterna i Artportalen och vad som hittades i Street View om man inkluderade de oidentifierbara växterna. När man exkluderade oidentifierade växter eller när man inkluderade områden som inte kunde nås visade det en signifikant skillnad. Att använda Google Street View för att komplettera Artportalen-data för R. japonica har både fördelar och begränsningar. Många områden var omöjliga att nå, men där de var 2 tillgängliga visade det sig effektivt för att identifiera felrapporter och hitta orapporterade växter utan att behöva besöka platsen. Street View-data kan förbättra tillförlitligheten av distributionsdata som används för att övervaka invasiva arter utan att man någonsin behöver resa, men det kan inte fullt byta ut andra metoder att öka tillförlighet och för bästa resultat är en kombination av Street View och platsbesök nödvändig.

Prior to 1993, freshwater angling in South Africa had been governed by the respective nature conservation legislation of the four South African provinces, the four “independent homelands" and the six so-called Bantustans. In 1993 a South Africa with nine provinces was created, of which only Limpopo and Mpumalanga promulgated its own laws governing freshwater angling. From 2008 angling for listed threatened and protected freshwater fish species has been regulated by the National Environmental Management: Biodiversity Act, supplemented by the Threatened or Protected Species Regulations. In addition, it is anticipated that the Alien and Invasive Species Regulations, which will regulate angling for listed alien and invasive freshwater fish, will be promulgated in the near future. The result is that freshwater angling is currently being governed by a plethora of pre-1993 provincial, homeland and Bantustan legislation, two post-1993 provincial acts, as well as post-1993 national legislation. In this dissertation the South African freshwater angling legislative framework was critically analysed. It was found that the multitude of fragmented and complex laws, created 15 “angling provinces” which leads to confusion amongst anglers and government officials alike. In the process legal certainty and reasonableness, cornerstones of a sound legal system, are being compromised, indigenous freshwater fish are not adequately protected and alien or invasive freshwater fish are not properly managed. In the light of the above, and after taking comments by anglers and enforcement officials into account, recommendations are made for an improved legislative framework for freshwater in South Africa. It is recommended that all freshwater fish species be managed and/or protected on a catchment basis, as opposed to the current provincial basis. This will ensure legal certainty and reasonableness and that all indigenous freshwater fish which are subject to the similar threats are protected adequately and uniformly. / Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2010.

Prior to 1993, freshwater angling in South Africa had been governed by the respective nature conservation legislation of the four South African provinces, the four “independent homelands" and the six so-called Bantustans. In 1993 a South Africa with nine provinces was created, of which only Limpopo and Mpumalanga promulgated its own laws governing freshwater angling. From 2008 angling for listed threatened and protected freshwater fish species has been regulated by the National Environmental Management: Biodiversity Act, supplemented by the Threatened or Protected Species Regulations. In addition, it is anticipated that the Alien and Invasive Species Regulations, which will regulate angling for listed alien and invasive freshwater fish, will be promulgated in the near future. The result is that freshwater angling is currently being governed by a plethora of pre-1993 provincial, homeland and Bantustan legislation, two post-1993 provincial acts, as well as post-1993 national legislation. In this dissertation the South African freshwater angling legislative framework was critically analysed. It was found that the multitude of fragmented and complex laws, created 15 “angling provinces” which leads to confusion amongst anglers and government officials alike. In the process legal certainty and reasonableness, cornerstones of a sound legal system, are being compromised, indigenous freshwater fish are not adequately protected and alien or invasive freshwater fish are not properly managed. In the light of the above, and after taking comments by anglers and enforcement officials into account, recommendations are made for an improved legislative framework for freshwater in South Africa. It is recommended that all freshwater fish species be managed and/or protected on a catchment basis, as opposed to the current provincial basis. This will ensure legal certainty and reasonableness and that all indigenous freshwater fish which are subject to the similar threats are protected adequately and uniformly. / Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2010.

This thesis examines restoration of Garry oak ecosystems in Southwestern British Columbia, Canada. Before the arrival of European settlers, Coast Salish peoples practiced intensive stewardship and cultivation practices that heavily shaped Garry oak ecosystems. These long-standing stewardship practices are responsible for the abundance of culturally important plants found in Garry oak ecosystems today. In addition to their cultural value to Coast Salish peoples, Garry oak ecosystems also support unique biodiversity, including numerous at-risk species. These ecosystems and the values they embody came under threat with the arrival of European settlers, who introduced non-native plants and excluded Coast Salish peoples and their stewardship practices from these ecosystems. Today, Garry oak ecosystems have been reduced to a fraction of their pre-colonial distribution and remaining patches are typically heavily invaded by both native and non-native plants. Their cultural and biological values coupled with ongoing degradation has motivated both Indigenous and non-Indigenous land managers to implement restoration programs in Garry oak ecosystems. To inform future restoration efforts, this thesis examines ecological impacts of a long-term restoration program and a wildfire in a lək̓ʷəŋən Garry oak ecosystem at Mill Hill Regional Park near Langford, British Columbia. In Project 1, vegetation responses to a 13-year invasive species removal program were quantified to determine if native plant populations were successfully bolstered by the removal efforts. In Project 2, impacts of an unintended wildfire on the relative cover of native and non-native plants were examined. This attempted to explore potential ecosystem shifts that may occur as wildfires increase in frequency and severity as predicted by climate models. In Project 1, the greatest change observed after invasive species removal was an increase in other introduced species, while increases in native species were not statistically significant. In Project 2, introduced Anthoxanthum odoratum was facilitated by fire while native Camassia spp. were reduced by it. Taken together, these results demonstrate the complexity of restoring Indigenously managed ecosystems where multiple introduced species have existed for long periods. Invasive species, specifically Anthoxanthum odoratum, showed greater responses to removal efforts and wildfire than native species. Intensive, long-term restoration programs that utilize multiple tools, including low-intensity fire, invasive removal, herbicide, and seeding of native species appear necessary to bolster native species without unintentional facilitation of introduced species. Coast Salish peoples and stewardship practices were integral in maintaining these ecosystems before the arrival of European settlers and should play a key role in their restoration today, though traditional practices will likely need adapted to account for environmental changes caused by colonization. Furthermore, to avoid continuing the cultural damage that began with colonization, it is vital that Coast Salish First Nations lead or be directly involved in restoration of these ecosystems, which continue to hold irreplaceable cultural value. / Graduate / 2023-01-14

<p dir="ltr">To reduce the establishment and spread of invasive plant species, the Environmental Quality Incentive Program (EQIP) was created in 1996 to provide financial and technical assistance to private landowners to aid in conservation practices and address environmental concerns. From 2014-2022, approximately $90 million dollars was obligated to the EQIP for completed contracts of over 240,000 hectares in Indiana. However, to date, there has been no examination of whether participation in conversation cost sharing programs has resulted in the recovery of native tree diversity, growth, and reproduction following the treatment of invasive plants. Furthermore, there is a gap in our understanding of the effectiveness of EQIP and its success in achieving and maintaining management goals. This thesis quantifies the composition, diversity, regeneration density and growth of tree species in response to invasive plant treatments at sites that participated in the EQIP. In particular, I investigated how the species composition of woody seedlings (stems < 2 cm dbh) and woody saplings (2 – 5 cm dbh) differed across EQIP-treated and untreated reference plots. I then examined how native species richness and diversity values differed between EQIP-treated and untreated plots. Lastly, I used dendroecological methods to determine how treatment of invasive shrubs affected overstory tree growth. Across the state, I found that native species richness of seedlings and saplings was greater in EQIP-treated plots then within reference plots. Reference plots were associated with invasive species such as <i>Lonicera maackii</i> (Amur honeysuckle), <i>Rosa multiflora</i> (multiflora rose), <i>Elaeagnus umbellata</i> (autumn olive) and <i>L. japonica</i> (Japanese honeysuckle), while EQIP-treated plots were associated with native tree species, such as <i>Carya ovata</i> (shagbark hickory),<i> Ulmus americana </i>(American elm), <i>Fraxinus americana</i> (white ash), <i>Liriodendron tulipifera</i> (yellow-poplar), <i>Quercus alba</i> (white oak), <i>Q. velutina</i> (black oak), and shrubs, such as <i>Rubus allegheniensis</i> (Allegheny blackberry) and <i>Lindera benzoin</i> (spicebush). I observed that trees generally had greater basal area increment growth following invasive shrub treatments; therefore, the reduction of invasive shrub dominance on EQIP-enrolled lands has led to a small, but significant, increase in overstory tree growth. I observed high within-group variability in growth for EQIP-treated and reference plots, likely due to differing management strategies across privately owned forests. Overall, my results demonstrate that participation in the EQIP has positively benefited species richness, and native species composition, and tree growth.</p>

Exotic species alter the streamside plant community by changing the resources available to the stream food web, causing cascading changes throughout the entire aquatic ecosystem. To better understand the impacts of exotic litter species on stream communities, investigations were made at global and local levels. A meta-analysis was performed to understand which environmental and litter quality factors impact native and exotic litter decay rates on the global scale. It was found that exotic species are likely to decay faster than native species at larger mesh sizes, and in warm temperature environments because high quality exotic leaves have a lower C:N ratio than native leaves. An urban litter decay experiment in Victoria, B.C. streams contrasting Alnus rubra, Salix sitchensis, Hedera sp., Rubus armeniacus and plastic trash found that trash decays more slowly than leaf litter, but leaf species all decay at the same rate, and stream invertebrates colonize all litter types equally. Significant differences in litter decay rates and invertebrate community alpha and Shannon diversities were also observed across the four different streams. The more that is learned about the impacts of exotic leaf litter, the better we are able to respond to keep streams as healthy and as biodiverse as possible. / Graduate / 2017-08-10 / 0329 / 0793 / kimkenn@uvic.ca

Le criocère du lis, Lilioceris lilii (Coleoptera : Chrysomelidae), un ravageur de lis et de fritillaires d’origine eurasienne, a été observé pour la première fois en Amérique du Nord en 1943 sur l’Ile de Montréal au Canada. Après y avoir été confiné pendant environ 25 années, ce coléoptère a par la suite progressé rapidement sur le territoire nord-américain. Actuellement, on l’observe dans huit provinces canadiennes et huit états américains. Cette étude a investigué les routes d’invasion utilisées par le criocère du lis au Canada et aux États- Unis avec l’aide de marqueurs génétiques AFLP. Pour ce faire, 516 individus parmi 34 sites en Amérique du Nord et en Europe ont été échantillonnés et analysés. Le premier objectif était de déterminer, en analysant la structure génétique des populations nord-américains, s’il y avait eu une ou plusieurs introductions en provenance d’Europe. Le deuxième objectif était d’identifier l’origine de la ou des populations introduites en Amérique du Nord. Finalement, le troisième objectif consistait à proposer un scénario d’invasion de L. lilii en Amérique du Nord basé sur les données de première mention et de structure génétique des populations échantillonnées. Les résultats démontrent une signature génétique distincte entre les criocères du lis du Canada et ceux des États-Unis, suggérant ainsi deux sources d’introductions indépendantes en Amérique du Nord, soit une première introduction à Montréal, Québec, dans les années 1940 et une seconde aux États-Unis au début des années 1990 à Cambridge, Massachusetts. De plus, les deux populations nord-américaines semblent provenir de différentes régions du nord de l’Europe, ce qui est conséquent avec le scénario suggérant deux sources d’introductions indépendantes. Chacune des populations aurait par la suite progressé respectivement dans leur pays d’introduction selon une dispersion de type stratifiée. En effet, la progression continue de L. lilii dans certaines régions suggère une dispersion naturelle de l’espèce sur le territoire nord-américain, alors que la progression rapide sur de longues distances semble être causée par le transport anthropique de lis contaminés. / The lily leaf beetle, Lilioceris lilii (Coleoptera : Chrysomelidae), a Eurasian pest of lilies and fritillaries, was first observed in North America in 1943 on the Island of Montréal, Canada. After being confined to Montréal for approximately 25 years, the beetle quickly progressed in North America, and is currently present in eight Canadian provinces and eight American states. During this study, we have investigated the routes of invasion followed by L. lilii in North America, using AFLP markers. We sampled and analysed 516 individuals from 34 sites across North America and Europe. Our first objective was to characterize the genetic structure of North American L. lilii populations to determine if they originated from a single or form multiple introductions from Europe. The second objective was to identify the geographical origin of the invasive population(s). Finally, the third objective was to trace back the geographical routes of invasion of L. lilii in North America, using information from both the dates of first observations and the genetic structure of sampled populations. Our results showed clear genetic difference between individuals from Canada and the USA, suggesting at least two different sources of introductions of L. lilii in North America. A first episode of introduction took place in Montréal, Canada in the 1940’s while a second introduction occurred in Cambridge, Massachusetts, around 1990. Also, both North American populations seem to originate from different populations in northern Europe, which support the hypothesis of two distinct sources of introduction. Each population next progressed in its respective country following a stratified dispersal. Indeed, continuous progression of the beetle in some regions of North America suggests a pattern of natural dispersion, while human-mediated carrying of infected lilies seemed to be responsible for the long-range movement of the beetle.