Reke Srbije kao putevi invazije - istočni koridor invazije Reynoutria spp.

Increasing levels of invasion worldwide have been the source of concern for scientists, due to significant costs and efforts required for managing them. The knowledge of invasion pathways, both those of initial introduction and subsequent spread, is of key importance, since further increase in the number of pathways and vectors of invasion is predicted for the 21st century. At regional scales habitat type has proven to be a reliable predictor of the level of invasion, as certain habitat types (i.e. frequently disturbed, under strong anthropogenic influence) is characterized by high invasion levels. Riparian habitats, as hotspots of alien species diversity and primary sources of their spread, represent some of the most important invasion corridors, where water acts as an effective dispersal mechanism. Some invasive plant species, like Reynoutria spp. show a strong tendency to invade riparian habitats. Preliminary findings of field surveys aimed to assess the level of riparian invasion by Reynoutria spp. in Serbia suggest that some river basins are significantly affected by the presence of these invasive species. Bearing in mind the principal means of their propagation, further spread of Reynoutria spp. along the rivers in Serbia is to be expected over the following years.Stepen invazija koji je u porastu širom sveta zabrinjava naučnike, zbog značajnih troškova i napora koji su neophodni u njihovom kontrolisanju. Poznavanje puteva invazije, kako početnog unosa tako i naknadnog širenja vrsta, od ključnog je značaja, jer je u 21. veku prognoziran dalji porast broja puteva i vektora invazije. Na regionalnom nivou tip staništa se pokazao kao pouzdani pokazatelj nivoa invazije, jer određene tipove staništa (često remećena, pod snažnim antropogenim uticajem) karakteriše visok nivo invazije. Riparijalna staništa, kao centri diverziteta alohtonih vrsta i primarni izvor njihovog širenja, predstavljaju neke od najznačajnijih koridora invazije, u kojima voda deluje kao uspešan mehanizam disperzije. Neke invazivne vrste biljaka, poput Reynoutria spp. pokazuju snažnu tendenciju ka invaziji riparijalnih staništa. Preliminarni rezultati terenskih istraživanja koji su za cilj imali procenu nivoa invazije riparijalnih staništa vrstama roda Reynoutria u Srbiji ukazuju na to da su slivovi nekih reka pod značajnim uticajem prisustva ovih invazivnih vrsta. Imajući u vidu osnovni vid njihove propagacije, dalje širenje Reynoutria spp. duž reka u Srbiji može se očekivati tokom narednih godina

The faunal Ponto-Caspianization of central and western European waterways

As alien invasive species are a key driver of biodiversity loss, understanding patterns of rapidly changing global species compositions depends upon knowledge of invasive species population dynamics and trends at large scales. Within this context, the Ponto-Caspian region is among the most notable donor regions for aquatic invasive species in Europe. Using macroinvertebrate time series collected over 52 years (1968–2020) at 265 sites across 11 central and western European countries, we examined the occurrences, invasion rates, and abundances of freshwater Ponto-Caspian fauna. We examined whether: (i) successive Ponto-Caspian invasions follow a consistent pattern of composition pioneered by the same species, and (ii) Ponto-Caspian invasion accelerates subsequent invasion rates. In our dataset, Ponto-Caspian macroinvertebrates increased from two species in 1972 to 29 species in 2012. This trend was parallelled by a non-significant increasing trend in the abundances of Ponto-Caspian taxa. Trends in Ponto-Caspian invader richness increased significantly over time. We found a relatively uniform distribution of Ponto-Caspian macroinvertebrates across Europe without any relation to the distance to their native region. The Ponto-Caspian species that arrived first were often bivalves (46.5% of cases), particularly Dreissena polymorpha, followed secondarily by amphipods (83.8%; primarily Chelicorophium curvispinum and Dikerogammarus villosus). The time between consecutive invasions decreased significantly at our coarse regional scale, suggesting that previous alien establishments may facilitate invasions of subsequent taxa. Should alien species continue to translocate from the Ponto-Caspian region, our results suggest a high potential for their future invasion success highly connected central and western European waters. However, each species’ population may decline after an initial 'boom' phase or after the arrival of new invasive species, resulting in different alien species dominating over time

Euryhalinity of Ponto-Caspian invaders in their native and introduced regions

In the past several decades, Ponto-Caspian species have established in freshwater and brackish habitats of the North and Baltic Sea and Great Lakes-St. Lawrence River region in much higher numbers than expected based on introduction effort (i.e. shipping frequency) and environmental conditions between these regions. Several studies have suggested that Ponto-Caspian taxa are euryhaline and might be able to adapt rapidly to changing salinity conditions, and therefore may be more successful colonizers than species from other regions. To determine the realized niche in the native and introduced habitats of Ponto-Caspian invaders and to assess whether they have expanded their salinity tolerance during the invasion process, we conducted a literature search to assess the salinity ranges of 55 Ponto-Caspian species in their native and introduced ranges. Our results confirmed that the majority of those species occupied a wide range of salinity in their native and introduced habitats. Approximately 50% of species were reported from both freshwater and brackish habitats (0–18 PSU) in their native region, occupying a salinity range of at least 10 PSU difference. In general, the number of species tended to decline as salinity increased in both native and introduced habitats. More than 90% of Ponto-Caspian invaders occupied freshwater (< 0–0.5 PSU) habitats, while 18% did not occur above 18 PSU. Overall, 46% of species were reported from a narrower salinity range in their introduced compared to their native region. Consequently, our study revealed significantly broader salinity ranges in native compared to introduced habitats. As our results suggest that the majority of Ponto-Caspian invaders occupy freshwater and brackish habitats in their native region, the recent numerous invasions of freshwater and brackish areas by these species should not be a surprise. Therefore, managers and policy makers should take into account that the majority of Ponto-Caspian invaders originate from fresh water or low salinities and develop new regulations to prevent future invasions from the Ponto-Caspian region, as well as from areas highly invaded by Ponto-Caspian taxa such as Northern Europe

Using Remote Sensing and GIS to Assess the Effects of Land Use/Cover Change and Geographic Variables on the Spread of Poisonous Invasive Giant Hogweed in Latvia

Land-use land-cover change (LULCC) especially those caused by human activities, is one of the most important components of global environmental change (Jessen, 2005). This dissertation analyses the effects of geographic, biographical, and demographic factors on LULCC and how LULCC and geographic variables influence the spread of invasive Giant Hogweed in northeastern Latvia. Data sets used in this study include: remote sensing images (Landsat Thematic Mapper acquired in 1992 and 2007), global positioning system (GPS data), census data, and data from public participation geographic information systems (PPGIS). These data were processed and analysed in a geographic information system (GIS). Six categories of land-cover were studied to determine land-cover change (LCC) and the relationship to population change between 1992 and 2007. Classification and analyis of the 1992 and 2007 Landsat images revealed that land-cover changing to forest is the most common type of change (17.1% of pixels) followed by changes to agriculture (8.6% of pixels) and the least was changes to urban/suburban (0.8% of pixels). Integration of the census data and land-cover classification revealed interesting patterns, for example, that population density is positively correlated with percent change to forest, agriculture and urban. Modeling the spread of Giant Hogweed was achieved using logistic regression and a novel cluster analysis approach. The logistic regression model was used to model the spread of Giant Hogweed using presence and pseudo-absence data of Giant Hogweed, while cluster analysis used only Giant Hogweed presence data. Both models were run using data from a series of GIS layers including topographic and LULCC information. The results from logistic regression and cluster analysis show that Giant Hogweed is more likely to grow near roads, near rivers, in proximity to urban centers and in low elevation areas. Habitat suitability maps produced from both models indicate where Giant Hogweed is more likely to spread in the future and can serve as useful tools for policy makers and land managers to focus their efforts to manage weed invasions, and identify similar habitats where Giant Hogweed may occur in the future

Strategy and Action Plan for Mire and Peatland Conservation in Central Europe

Western Europe has now lost most of its natural peatlands, largely as a result of agricultural and industrial development. Whilst similar influences have affected peatlands in Central Europe (CE), losses have so far been less severe, so that this region still harbours many excellent examples of peatland types that are virtually extinct further west. This report acts as a strategy and action plan to support conservation in CE

Strategy and Action Plan for Mire and Peatland Conservation in Central Europe: Central European Peatland Project (CEPP)

Peatlands are vital economic and ecological resources which contribute to biological, landscape and cultural diversity. They comprise characteristic assemblages of species which can exhibit intense patterning of plant and animal communities. Peatlands are also the best ecosystem for sequestering carbon (with current stores far exceeding those held in rainforests). Guidelines for Global Action on Peatlands were agreed at the last Conference of Parties to the Ramsar Convention. These guidelines note that “There is a wide range of threats to peatlands that require urgent national and/or international action”. To help counter these threats, the Ramsar Convention is working with its sister conventions, on biodiversity and climate change. The Ramsar Secretariat is pleased to see this report, which provides a significant step forward by presenting a summary of current knowledge and a Strategy and an Action Plan for Central Europe; a region that still harbours large peatland areas and types which are virtually extinct elsewhere. But changes in land management, ownership and the nature of economic exploitation are now placing peatland in this region under increasing threat. This present publication will help inform all concerned to achieve better governance, and thereby management and conservation, for Peatlands in Central Europe

Predicting future changes in the distribution of wandering spiders - Habitat requirement, cold tolerance, and dispersal are crucial traits for Dolomedes species.

Å forstå dynamikken i en arts utbredelsesområde er viktig for å kunne forvalte den best mulig. Teoretiske modeller forutsier ekspansjon av utbredelsen til arters habitater mot polene i takt med klimaendringene. Noen arter er i stand til å tilpasse seg sine nye klimatiske forhold, andre arter vil det bli mindre vanlige, og andre igjen er i stand til å følge etter den geografiske habitatutbredelsen. Disse tre mulighetene er ikke gjensidig utelukkende for en art. Denne oppgaven tar sikte på å evaluere de to europeiske fiskeedderkoppene sine evner til å følge fremtidig habitatsutbredelse. Dolomedes plantarius og Dolomedes fimbriatus er begge utbredt i Europa, men førstnevnte har færre populasjoner og er klassifisert som sårbar på IUCNs rødliste for trua arter. Begge artene er semi-akvatiske og er derfor avhengig av våtmarker, som er truet av klimaendringer og menneskelig aktivitet. Hovedmålet med oppgaven var å undersøke habitatkravene, tilbøyeligheten for spredning og kuldetoleransen til begge nevnte arter for å effektivt kunne forutsi deres fremtidige habitatutvalg samt deres evne til å forflytte seg for å nå disse innenfor Fennoscandia. Vi gjennom gikk hvordan og i hvilket omfang artsdistribusjonsmodeller (SDMer) benyttes I studier på leddyr, og gjorde tilnærminger for å redusere forstyrrelsene i SDM-prediksjonene. Vi viste at bruk av hybride artsdistribusjonsmodeller (hybride SDMer) bør favoriseres over enkle korrelative SDMer ved å inkludere prosessbasert informasjon i korrelasjonsmodeller. Vi bestemte oss for å utvikle hybride SDMer for å forutsi innvirkningen klimaendringer vil kunne ha på Dolomedes. For å gjøre dette, samlet vi forekomstdata påbegge arter og kjørte fysiologiske og eksperimentelle tester for å utforske henholdsvis deres habitatkrav, kuldetoleranse og tilbøyelighet til spredning. Vi fant smalere habitatkrav for D. plantarius enn for D. fimbriatus; sympatriske leveområder var faktisk mer lik D. plantarius-leveområder enn D. fimbriatus-leveområder. Løvskog, (langsomtflytende) vann og lavereliggende områder er nødvendig for D. plantarius, mens D. fimbriatus tåler lavere pH (barskog), fravær av vann og kan okkupere i høyereliggende områder. Når det gjelder kuldetoleranse for fiskeedderkopper, fant vi at ungdommer av D. fimbriatus fra nordlige (kontinentale) populasjoner var mer tolerante enn ungdommer fra sørlige (tempererte) populasjoner. Videre var D. plantarius litt mindre kuldetolerant enn D. fimbriatus I Fennoscandia. D. fimbriatus hadde en høyere tilbøyelighet til spredning av langdistanse (balloning) og vannbåren (seilende), mens tilbøyeligheten for kortdistansespredning (rappellering) ikke var forskjellig mellom arter. For kortreist vannbåren spredning, derimot, fant vi høyere tilbøyelighet for roing og lavere tilbøyelighet til å løpe for D. plantarius enn for D. fimbriatus. Til slutt, med korrelative SDM-er, viste vi at utbredelsen av egnede habitat og klima vil utvide seg nordover i takt med klimaendringene, og at dette skiftet vil være viktigere under scenarioer med større klimaendringer. Likevel estimerte vi med bruk av hybrid SDM at muligheten for begge artene til å spore egnede habitater vil være begrenset. Det skyldtes hovedsakelig begrenset spredningsevne og/eller fragmentering av landskapet. Forsinkelsen Dolomedes viste i forhold til å følge endringene i habitatutbredelsen understreker behovet for en oppdatering av deres rødliste-status, samt behov for planlegging av forvaltningen av arten for å bevare den. Å bevare forbindelsen mellom leveområder er avgjørende, samt å utforske Dolomedes sin vinteroverlevelse.Abstract Understanding the dynamic of the range of a species is important for its conservation and management planning. Theoretical models predict poleward expansions of the suitable habitat of species under climate change. Some species are able to adapt to their new climatic conditions, others species will decline and others are able to track their suitable habitats. These three responses are not mutually exclusive along the range of a species. This thesis aimed at evaluating the abilities of the two European fishing spiders to track their suitable range in the future. Dolomedes plantarius and Dolomedes fimbriatus are widespread in Europe but the former has scarcer populations and is classified as vulnerable by the IUCN red list of species. Both species are semi-aquatic and consequently inhabit wetlands, which are threatened by climate change and human activities. The main goal of this thesis was to explore the habitat requirements, the propensity for dispersal and the cold tolerance of both species to efficiently predict their range of habitat suitability and reachability in Fennoscandia. We reviewed scopes and ways species distribution models (SDMs) are used in arthropods studies and provided approaches to mitigate the biases of SDMs predictions. We showed that using hybrid species distribution models (hybrid SDMs) should be favoured over simple correlative SDMs by including process-based information in correlative models. We decided to develop hybrid SDMs to predict the impact of climate change on Dolomedes. To do so, we sampled occurrence data on both species and ran physiological and experimental tests to explore their habitat requirements, cold tolerance and propensity for dispersal. We found narrower habitat requirements for D. plantarius compared to D. fimbriatus; sympatric sites were indeed more similar to D. plantarius sites than to D. fimbriatus sites. Deciduous forest, (slow-flowing) water, and low altitude are needed for D. plantarius, whereas D. fimbriatus tolerate lower pH (coniferous forest), absence of water, and can occupy higher altitudes. Regarding cold tolerance of juveniles fishing spiders, we showed that D. fimbriatus from northern (continental) populations were more tolerant than from southern (temperate) populations. Moreover, D. plantarius was slightly less cold tolerant than D. fimbriatus in Fennoscandia. D. fimbriatus had a higher propensity for long-distance airborne (ballooning) and waterborne (sailing) dispersal, while the propensity for short-distance airborne dispersal (rappelling) did not differ between species. However, we found contrasting results for shortdistance waterborne dispersal, with a higher propensity for rowing and a lower propensity for running for D. plantarius than for D. fimbriatus. Finally, with correlative SDMs we showed that climatic suitability and habitat suitability will expand northward with climate change and that this shift will be more important under stronger climate change. Nonetheless, with hybrid SDMs we predicted that the ability for both species to track their suitable habitats will be limited due to limited dispersal abilities and/or fragmentation of the landscape. The lag of Dolomedes behind their suitable range underscores the urgent need for an update of their red-listed status, as well as the needs for planning of conservation and management strategies. Conserving the connectivity between sites is crucial, as well as exploring winter survival of Dolomedes