Browsing by Subject "invasive species"

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  • Nummi, Petri; Väänänen, Veli-Matti; Pekkarinen, Antti-Juhani; Eronen, Visa; Mikkola-Roos, Markku; Nurmi, Jarkko; Rautiainen, Antti; Rusanen, Pekka (Baltic Forestry, 2019)
    Baltic Forestry, 25(2), 228-237
    Alien predators are known to potentially strongly affect their prey populations. We studied the impact of raccoon dogs (Nyctereutes procyonoides) on waterbird breeding success in eight semi-urban wetlands in Finland. We manipulated raccoon dog density in two wetlands by removing individuals (2002 protection year, 2003 and 2004 removal years). We additionally performed nest predation experiments. We monitored raccoon dog density, estimated hunting bag size and observed waterbird breeding success. Our hypothesis predicts that the omnivorous raccoon dog plays a role in waterbird breeding success by depredating nests. Our experiments shown that the raccoon dog hunting bag in eutrophic wetlands may be large, as we removed 8.6–20.0 animals per km2. Both our nest predation experiment and field data indicated that raccoon dogs affect the breeding success of waterbirds. We found a significant relationship between raccoon dog density index and predation rate of the artificial nests, but not between red fox (Vulpes vulpes) density and predation on artificial nests. We did not find an association between raccoon dog abundance and the breeding success of mallards (Anas platyrhynchos) and great crested grebes (Podiceps cristatus). However, our study shows that birds species with different breeding strategies – e.g. great crested grebe, mute swan (Cygnus olor), mallard, Eurasian wigeon (Mareca penelope), coot (Fulica atra), lapwing (Vanellus vanellus) and marsh harrier (Circus aeruginosus) – when considered together showed higher breeding success both in 2003 and 2004 when compared to breeding success before removal. There was, however, variation in how strongly the species responded to raccoon dog removal. Our results indicate that the removal of alien raccoon dogs can be an important tool in wetland management.
  • Bernard, Guillaume; Kauppi, Laura; Lavesque, Nicolas; Ciutat, Aurelie; Gremare, Antoine; Masse, Cecile; Maire, Olivier (2020)
    The invasive mussel Arcuatula senhousia has successfully colonized shallow soft sediments worldwide. This filter feeding mussel modifies sedimentary habitats while forming dense populations and efficiently contributes to nutrient cycling. In the present study, the density of A. senhousia was manipulated in intact sediment cores taken within an intertidal Zostera noltei seagrass meadow in Arcachon Bay (French Atlantic coast), where the species currently occurs at levels corresponding to an early invasion stage. It aimed at testing the effects of a future invasion on (1) bioturbation (bioirrigation and sediment mixing) as well as on (2) total benthic solute fluxes across the sediment-water interface. Results showed that increasing densities of A. senhousia clearly enhanced phosphate and ammonium effluxes, but conversely did not significantly affect community bioturbation rates, highlighting the ability of A. senhousia to control nutrient cycling through strong excretion rates with potential important consequences for nutrient cycling and benthic-pelagic coupling at a broader scale. However, it appears that the variability in the different measured solute fluxes were underpinned by different interactions between the manipulated density of A. senhousia and several faunal and/or environmental drivers, therefore underlining the complexity of anticipating the effects of an invasion process on ecosystem functioning within a realistic context.
  • Pieterse, Arnold; Rytkönen, Mari; Hellsten, Seppo (Finnish Environment Institute, 2009)
    Reports of the Finnish Environment Institute 15/2009
  • Rolls, Robert J.; Hayden, Brian; Kahilainen, Kimmo K. (2017)
    Climate change and species invasions represent key threats to global biodiversity. Subarctic freshwaters are sentinels for understanding both stressors because the effects of climate change are disproportionately strong at high latitudes and invasion of temperate species is prevalent. Here, we summarize the environmental effects of climate change and illustrate the ecological responses of freshwater fishes to these effects, spanning individual, population, community and ecosystem levels. Climate change is modifying hydrological cycles across atmospheric, terrestrial and aquatic components of subarctic ecosystems, causing increases in ambient water temperature and nutrient availability. These changes affect the individual behavior, habitat use, growth and metabolism, alter population spawning and recruitment dynamics, leading to changes in species abundance and distribution, modify food web structure, trophic interactions and energy flow within communities and change the sources, quantity and quality of energy and nutrients in ecosystems. Increases in temperature and its variability in aquatic environments underpin many ecological responses; however, altered hydrological regimes, increasing nutrient inputs and shortened ice cover are also important drivers of climate change effects and likely contribute to context-dependent responses. Species invasions are a complex aspect of the ecology of climate change because the phenomena of invasion are both an effect and a driver of the ecological consequences of climate change. Using subarctic freshwaters as an example, we illustrate how climate change can alter three distinct aspects of species invasions: (1) the vulnerability of ecosystems to be invaded, (2) the potential for species to spread and invade new habitats, and (3) the subsequent ecological effects of invaders. We identify three fundamental knowledge gaps focused on the need to determine (1) how environmental and landscape characteristics influence the ecological impact of climate change, (2) the separate and combined effects of climate and non-native invading species and (3) the underlying ecological processes or mechanisms responsible for changes in patterns of biodiversity.
  • Puntila-Dodd, R.; Bekkevold, D.; Behrens, J. W. (Springer, 2021)
    Hydrobiologia 848: 2
    Species invasions often occur on coasts and estuaries where abiotic conditions vary, e.g. salinity, temperature, runoff etc. Successful establishment and dispersal of non-indigenous species in many such systems are poorly understood, partially since the species tend to show genetic and ecological plasticity at population level towards many abiotic conditions, including salinity tolerance. Plasticity may be driven by shifting expression of heat shock proteins such as Hsp70, which is widely recognized as indicator of physical stress. In this study, we developed a qPCR assay for expression of the hsp70 gene in the invasive round goby (Neogobius melanostomus) and tested the expression response of fish collected from a brackish environment in the western Baltic Sea to three different salinities, 0, 10 and 30. hsp70 expression was highest in fresh water, indicating higher stress, and lower at brackish (ambient condition for the sampled population) and oceanic salinities, suggestive of low stress response to salinities above the population’s current distribution. The highest stress in fresh water was surprising since populations in fresh water exist, e.g. large European rivers and Laurentian Great Lakes. The results have implications to predictions for the species’ plasticity potential and possible range expansion of the species into other salinity regimes.
  • Laiho, Elina (Helsingin yliopisto, 2021)
    The European rabbit (Oryctolagus cuniculus) is a small mammal native to the Iberian Peninsula, but introduced by humans to all continents except Antarctica. The rabbit has been a remarkably successful invasive species due to its generalist nature and fast reproduction. Its spreading has mostly been destructive to the local nature, and humans have used fatal rabbit diseases such as rabbit haemorrhagic disease (RHD) to control harmful populations. The rabbit population in Helsinki is one of the most northern annually surviving rabbit populations in the world. It is believed to have originated from escaped pet rabbits in the late 1980s, and in the early 2000s, the rabbits spread rapidly around the Helsinki area. RHD spread unintentionally to Finland in 2016, and the disease caused a significant reduction in the Helsinki rabbit population. Rabbit population genetics has previously been studied in several countries, but never before in Finland. The aim of the thesis was to examine the genetic diversity and population structure of the Helsinki rabbit population before and after the RHD epidemic, and to compare the results to similar preceding rabbit population genetic studies. Rabbit populations have previously been found to recover from major population crashes without a notable loss in genetic diversity using DNA microsatellite markers. The recent RHD epidemic in Helsinki provided an opportunity to study, whether a rabbit population can recover from a population crash even in a harsher environment without losing genetic diversity. To conduct genetic analysis, fourteen DNA microsatellite loci were genotyped from individuals caught during two distinct time periods, in 2008-2009 (n=130) and in 2019-2020 (n=59). Population structure was observed in both temporal rabbit populations with small but significant FST values. The 2019-2020 population was more diverse than the 2008-2009 population in terms of allele numbers and expected heterozygosity. This result was unexpected considering the recent RHD-epidemic but could be explained by gene flow from new escaped rabbits. Compared to other wild rabbit populations around the world, the Helsinki area rabbits exhibit significantly lower genetic diversity. Bottleneck tests showed a significant signal separately in both temporal populations, but the RHD bottleneck cannot be distinguished based on the tests. The results could be biased by new gene flow, or the initial bottleneck caused by the founder effect of only a few pet rabbits. The rabbits have demonstrated their adaptation and survival skills in the cold climate of Helsinki. The population has significantly lower genetic diversity compared to other wild populations, yet recovered from a major RHD epidemic without reduction in genetic diversity under these more extreme environmental conditions. It has been proven again; the rabbit is a thriving invasive species.
  • Zalnierius, Tautvydas; Sveikauskas, Vaidevutis; Aphalo, Pedro J.; Gaveliene, Virgilija; Buda, Vincas; Jurkoniene, Sigita (2022)
    Sosnowsky's hogweed (Heracleum sosnowskyi Manden.), an important invasive species in Eastern Europe, is a monocarpic perennial plant that propagates exclusively by seeds. Hence, interfering with seed viability could help control its spread. In the present study, we investigated the effect of exogenous GA(3) (25, 100 and 150 mg/L) sprayed twice onto flowering H. sosnowskyi plants on the development of fruits (mericarps) and their ability to germinate under field conditions over the growing seasons of 2018 and 2019. Mericarps from plants sprayed with GA(3) failed to develop normally. The width/length ratio of mericarps decreased by 23% to 25% after 150 mg/L GA(3) application and their average weight decreased between 7% and 39% under all GA(3) treatments. X-ray radiographs revealed that the internal structure was malformed, with many of the mericarps lacking well-developed seeds. Proportionally fewer well-developed mericarps were produced by GA(3)-treated plants than water-sprayed control plants in 2018. Seed germination assessed outdoors in seeds buried in the ground was also severely reduced (from 58% to 99% after 150 mg/L GA(3) application). This indicates that exogenous GA(3) sprays result in incomplete seed development and a consequent decrease in viability and germination. As the highest GA(3) dose used resulted in significantly reduced propagation of Sosnowsky's hogweed through seeds in the field, GA(3) provides a promising approach to the control of the spread of this invasive weed species.
  • Pena-Peniche, Alexander; Mota-Vargas, Claudio; Garcia-Arroyo, Michelle; MacGregor-Fors, Ian (2021)
    Biological invasions occur when individuals of alien species establish and colonize new locations. The House Sparrow (Passer domesticus) is one of the most widespread invasive birds, native to Eurasia and North Africa, and has successfully invaded many regions from across the world. The House Sparrow was successfully introduced in 1852 into North America and quickly invaded most of the North American continent, except the Florida Peninsula. Currently, the species is found throughout agricultural and urban landscapes of North America except the Yucatan Peninsula. We analyzed the invasion process of the House Sparrow in order to determine why it is absent from the Yucatan Peninsula. For this, we focused our assessment on historical records of the species together with climatic variables. Using an ordination analysis, we compared the climatic space of the North American records for the House Sparrow with that of the Yucatan Peninsula, as well as those before and after the Florida Peninsula invasion, which took sparrows longer to fully colonize. We found that climate may represent an important driver in the process of invasion in the North American invasion of House Sparrows, probably delaying the Florida invasion, and so far, preventing the Yucatan Peninsula invasion. Our results suggest that the absence of the House Sparrow in the Yucatan Peninsula could be a temporal delay, as occurred in the Florida Peninsula; yet, climatic conditions in the Yucatan Peninsula show important differences from those of the Florida Peninsula. Given the species' plasticity and generalist life history traits, it is possible that the House Sparrow may overcome present climatic restrictions and invade the Yucatan Peninsula if proper management is not set in action.
  • Linnakoski, Riikka; Forbes, Kristian M. (2019)
  • Marton, Ana-Maria (Helsingfors universitet, 2011)
    Biological invasions affect biodiversity worldwide, and, consequently, the invaded ecosystems may suffer from significant losses in economic and cultural values. Impatiens glandulifera Royle (Balsaminaceae) is an invasive annual herb, native to the western Himalayas and introduced into Europe in the 19th century as a garden ornamental plant. The massive invasion of I. glandulifera is due to its high reproductive output, rapid growth and its ability to outcompete native species. In Finland, the first observations regarding the presence of I. glandulifera date from the year 1947, and today it is considered a serious problem in riparian habitats. The aim of this master’s thesis research is to reveal the population genetic structure of I. glandulifera in Finland and to find out whether there have been one or multiple invasions in Finland. The study focuses on investigating the origin of I. glandulifera in Southern Finland, by comparing plant samples from the Helsinki region with those from its native region and other regions of invasion. Samples from four populations in Helsinki and from the United Kingdom, Canada, India and Pakistan were collected and genotyped using 11 microsatellite markers. The genetic analyses were evaluated using the programs Arlequin and Structure. The results of the genetic analyses suggested that I. glandulifera has been introduced to Finland more than once. Multiple introductions are supported by the higher level of genetic diversity detected within and among Finnish populations than would be expected for a single introduction. Results of the Bayesian Structure analysis divided the four Finnish populations into four clusters. This geographical structure was further supported by pairwise Fst values among populations. The causes and potential consequences of such multiple introductions of I. glandulifera in Finland and further perspectives are discussed.
  • Lehmann, Philipp; Westberg, Melissa; Tang, Patrik; Lindstrom, Leena; Kakela, Reijo (2020)
    During winter insects face energetic stress driven by lack of food, and thermal stress due to sub-optimal and even lethal temperatures. To survive, most insects living in seasonal environments such as high latitudes, enter diapause, a deep resting stage characterized by a cessation of development, metabolic suppression and increased stress tolerance. The current study explores physiological adaptations related to diapause in three beetle species at high latitudes in Europe. From an ecological perspective, the comparison is interesting since one species (Leptinotarsa decemlineata) is an invasive pest that has recently expanded its range into northern Europe, where a retardation in range expansion is seen. By comparing its physiological toolkit to that of two closely related native beetles (Agelastica alniandChrysolina polita) with similar overwintering ecology and collected from similar latitude, we can study if harsh winters might be constraining further expansion. Our results suggest all species suppress metabolism during diapause and build large lipid stores before diapause, which then are used sparingly. In all species diapause is associated with temporal shifts in storage and membrane lipid profiles, mostly in accordance with the homeoviscous adaptation hypothesis, stating that low temperatures necessitate acclimation responses that increase fluidity of storage lipids, allowing their enzymatic hydrolysis, and ensure integral protein functions. Overall, the two native species had similar lipidomic profiles when compared to the invasive species, but all species showed specific shifts in their lipid profiles after entering diapause. Taken together, all three species show adaptations that improve energy saving and storage and membrane lipid fluidity during overwintering diapause. While the three species differed in the specific strategies used to increase lipid viscosity, the two native beetle species showed a more canalized lipidomic response, than the recent invader. Since close relatives with similar winter ecology can have different winter ecophysiology, extrapolations among species should be done with care. Still, range expansion of the recent invader into high latitude habitats might indeed be retarded by lack of physiological tools to manage especially thermal stress during winter, but conversely species adapted to long cold winters may face these stressors as a consequence of ongoing climate warming.
  • Länsipuro, Anna-Roosa (Helsingfors universitet, 2017)
    Kirjallisuustieteellinen tutkielma erittelee puutarhan käsitettä ja sen monimerkityksellistä suhdetta luonnon ja kulttuurin väliseen dikotomiaan. Puutarha voidaan nähdä luonnon ja kulttuurin välisenä kohtaamispaikkana ja yhteensovittajana, sekä metaforisella tasolla että käytännössä. Tutkielman lähtökohtana ja pääaineistona on laguna pueblo intiaanikirjailija Leslie Marmon Silkon teos Gardens in the Dunes (1999), jossa puutarhat ovat keskeisessä roolissa myös luonto/kulttuuri-dikotomian neuvottelemisessa. Romaanin päähenkilöiden suhteet omiin puutarhoihinsa kuvastavat sekä heidän luontosuhdettaan että ajatusmaailmaansa laajemmallakin tasolla. Nämä puolestaan näkyvät siinä, minkälaisin keinoin henkilöhahmot viljelevät ja hoitavat maata, sekä puutarhojen erilaisissa sosiaalisissa ja kasvatuksellisissa merkityksissä. Silkon teos sijoittuu pitkälti 1890-luvun Yhdysvaltojen läntisille alueille, muun muassa Sonoran aavikolle Kalifornian ja Arizonan osavaltioiden rajalla. Tämä on kulttuurihistoriallisesti ja maantieteellisesti kriittinen ajanjakso myös alkuperäiskansojen näkökulmasta, sillä virallisesti katsottiin "rajaseudun" (engl. Frontier) pysähtyneen vuoteen 1890 - samalla intiaaniheimot pakotettiin reservaatteihin, sisäoppilaitoksiin, tai pakkotöihin, ja yleisesti miellettiin intiaanien ns. perinteisen kulttuurihistorian myös käytännössä "pysähtyneen" tähän ajanjaksoon. Teoksessaan Silko kuitenkin kulkee rajaseudun jälkiä taaksepäin, vieden kirjan päähenkilöitä pitkälle matkalle kohti Yhdysvaltain itärannikkoa, aina Englantiin ja Italiaan asti. Kulttuurinen ja poliittinen ajankuva näkyy vahvasti myös matkan aikana kohdatuissa puutarhoissa. Tutkielma nostaa esille myös muutamia ekokritisismissä vakiintuneita käsitteitä kuten erämaa, pastoraali ja "ekologinen Intiaani" (engl. wilderness, pastoral ja "ecological Indian"). Nämä käsitteet ovat saaneet paljon huomiota niin kirjallisuus- kuin kulttuuritutkimuksessa yleensäkin, ja ne sisältävät vaikutusvaltaisia metaforia ja mielikuvia, jotka puolestaan näkyvät eri kulttuurien luontokäsitysten muodostamisessa. Tutkielma vertaa puutarhan käsitettä myös erämaan ja pastoraalin keskisiin piirteisiin, sekä puutarhan mahdollisuuksia paljastaa uusia, merkityksellisiä näkemyksiä ihmisen ja (ei-inhimillisen) luonnon väliseen suhteeseen. Tutkielman teoreettiinen aineisto koostuu useasta eri ekokriittisestä lähteestä. Kirjallisuusteorian osalta keskeiseen aineistoon kuuluvut muun muassa Laura Coltellin (toim.) Reading Leslie Marmon Silko: Critical Perspectives Through Gardens in the Dunes (2007); Mary Ellen Snodgrassin Leslie Marmon Silko: A Literary Companion (2011) Cheryl Glotfelteyin ja Harold Frommin (toim.) The Ecocriticism Reader: Landmarks in Literary Ecology (1996); Laurence Buellin The Environmental Imagination: Thoreau, Nature Writing and the Formation of American Culture (1995); Greg Garrardin Ecocriticism (2004); sekä Nancy Easterlinin A Biocultural Approach to Literary Theory and Interpretation (2012). Kirjallisuustieteen ulkopuolelta tulevaa aineistoa ovat muun muassa Mara Millerin taidefilosifinen tutkielma The Garden as an Art (1993), ja Ken Thompsonin Where Do Camels Belong? The Story and Science of Invasive Species (2015).