Forest disturbance by an ecosystem engineer : beaver in boreal forest landscapes

Natural disturbances are important for forest ecosystem dynamics and maintenance of biodiversity. In the boreal forest, large-scale disturbances such as wildfires and windstorms have been emphasized, while disturbance agents acting at smaller scales have received less attention. Especially in Europe beavers have long been neglected as forest disturbance agents because they were extirpated from most of their range centuries ago. However, now they are returning to many parts of their former distribution range. As a disturbance agent, beaver plays two roles: of an ecosystem engineer and of a herbivore. The engineering impact is realized through dam construction resulting in a transformation of an originally terrestrial ecosystem into an aquatic one. As herbivores, beavers affect stand structure and tree species composition by preferring deciduous trees over coniferous ones. After abandonment, a beaver pond gradually turns into a terrestrial habitat again. At well-drained sites, forest will return in due course, first dominated by deciduous trees. At poorly drained sites, moistness of beaver patches may result in fen development. We conclude that beaver has an important impact on ecosystem processes and biodiversity in boreal forest ecosystems because it creates and maintains a spatio-temporal mosaic of successional habitats and associated species communities that would otherwise not exist in the landscape.Peer reviewe

Restoring wetland biodiversity using research : Whole-community facilitation by beaver as framework

Wetlands are declining worldwide, and there is a great need for their restoration and creation. One natural agent of wetland engineering is beavers,Castorspp., which have returned or are returning to many parts of their former range. We initially studied the facilitative effect of the beaverCastor canadensison a waterbird community consisting of three waders and four ducks in boreal wetlands in southern Finland. Both waterbird species diversity and abundance increased when beavers impounded a pond. Common tealAnas creccaand green sandpiperTringa ochropuswere the species showing the most positive numerical response, but the other five species also increased upon flooding. This article evaluates how the results of the study have been used in management, both in theory and practice. The whole-community facilitation concept has been taken up in numerous articles considering the restorative effects of beavers. It has also been used as ecological background when planning and executing man-made wetland projects in Finland within both the public and the private sectors. Our study and its publication inAquatic Conservation: Marine and Freshwater Ecosystemshave set a foundation for further evidence-based management of waterbird communities. As the results show, having beavers as wetland managers is a feasible tool for creating and restoring wetlands for waterbirds and other biota. Moreover, wetland restoration projects are becoming more popular endeavours, owing to an understanding of the diverse benefits of wetlands. Flooding by beavers is used as a model for managers when creating man-made wetlands; for example, in urban areas where it is difficult to maintain beavers. 1.2.3.4.Peer reviewe

Populations in stable and variable habitats : Green and common sandpiper in a beaver-influenced landscape

Stability of breeding habitat use and population variability was studied in two common wader species: green sandpiper Tringa ochropus and common sandpiper Actitis hypoleucos in a boreal lake area in southern Finland. The main natural driver of habitat disturbance in the area is an ecosystem engineer, the North American beaver Castor canadensis. We also studied the presence and abundance of green sandpipers before, during and after beaver-induced floods. In the studied landscape, the variable habitat created by beaver flooding appeared to have carrying capacity for a larger green sandpiper population than the more stable habitat for that of the common sandpiper. Common sandpipers made much use of the same lakes from year to year whereas the occupation of wetlands by the green sandpiper was more variable. The population of common sandpipers fluctuated more, although they inhabited the more stable environment. Green sandpiper pair numbers increased during beaver flooding, which suggests that they adapt rapidly to changes in breeding site availability. Some of the facilitating effects of the beaver appeared to remain 1-2 years after the flooding.Peer reviewe

Urban Wetlands: A Review on Ecological and Cultural Values

Wetlands are a critical part of natural environments that offer a wide range of ecosystem services. In urban areas, wetlands contribute to the livability of cities through improving the water quality, carbon sequestration, providing habitats for wildlife species, reducing the effects of urban heat islands, and creating recreation opportunities. However, maintaining wetlands in urban areas faces many challenges, such as the reduction of hydrological functions, changed water regimes due to barriers, contamination by wastewater, habitat loss due to land-use change, and loss of biodiversity due to the entry of alien species. In this article, we review the theoretical background of wetlands in urban areas through the existing studies in the literature. We provide knowledge on urban wetlands and highlight the benefits of these wetlands in urban areas. These benefits include sustainability, biodiversity, urban heat islands, social perception, and recreation values. We also summarize the objectives, methodologies, and findings of the reviewed articles in five tables. In addition, we summarize the critical research gaps addressed in the reviewed articles. Our review study addresses the research gaps by performing a rigorous analysis to identify significant open research challenges, showing the path toward future research in the field. We further discuss and highlight the role of policymakers and stakeholders in preserving wetlands and finally present our conclusions

Urban water bodies and recreational opportunities in Finland

Urban water bodies provide recreational opportunities to residents such as swimming, boating, fishing and spending leisure time. The recreational opportunities offered by water bodies contributes to both physical and mental health. In Finland, there are almost unlimited possibilities to enjoy water bodies in urban areas by having 3.4 million hectares of inland water resources, e.g., lakes, ponds, and coastal wetland and 5.2 million hectares of marine waters. In this paper, we highlight the recreational values offered by these water areas in the urban context. We use water-based outdoor recreation statistics collected from the three provinces in Finland called Uusimaa, Pirkanmaa, and Pohjanmaa. As a result, we show that the demographic structure, access to the water areas are linked to the type of recreation activities such as swimming, fishing and boating. Thus, resulting in the well-being of people living in cities.Peer reviewe

Urban Wetlands: A Review on Ecological and Cultural Values

Wetlands are a critical part of natural environments that offer a wide range of ecosystem services. In urban areas, wetlands contribute to the livability of cities through improving the water quality, carbon sequestration, providing habitats for wildlife species, reducing the effects of urban heat islands, and creating recreation opportunities. However, maintaining wetlands in urban areas faces many challenges, such as the reduction of hydrological functions, changed water regimes due to barriers, contamination by wastewater, habitat loss due to land-use change, and loss of biodiversity due to the entry of alien species. In this article, we review the theoretical background of wetlands in urban areas through the existing studies in the literature. We provide knowledge on urban wetlands and highlight the benefits of these wetlands in urban areas. These benefits include sustainability, biodiversity, urban heat islands, social perception, and recreation values. We also summarize the objectives, methodologies, and findings of the reviewed articles in five tables. In addition, we summarize the critical research gaps addressed in the reviewed articles. Our review study addresses the research gaps by performing a rigorous analysis to identify significant open research challenges, showing the path toward future research in the field. We further discuss and highlight the role of policymakers and stakeholders in preserving wetlands and finally present our conclusions

Muukalaisia Maa-planeetalta

Laiduntavia lampaita Havaijilla, saalistaja-kissoja Australiassa, jokireitit valtaava vesihyasinttimatto Afrikassa ja alkuperäislajien kanssa risteytyviä sinisorsia Uudessa Seelannissa. Ihmisen siirtämät eläimet muuttavat pallomme eläimistöä ja kasvillisuutta monin tavoin ja yhä kiihtyvään tahtiin. On väitetty, että ensi vuosituhannen alkaessa tulokaslajien vaikutus luontoon olisi suurempi kuin kasvihuoneilmiön