Scientific names: Acer negundo L., Aceraceae. Synonyms: Negundo aceroides Moench (1794), Negundo fraxinifolium (Nutt.) DC. (1824). Common names: Box-elder, ash-leaved maple, manitoba maple (GB and US), Eschen-Ahorn (DE), askbladet lon (DK), saarvaher (EE), Saarnivaahtera (FI), askhlynur (IS), uosialapis klevas (LT), Oslapu kļava (LV), Vederesdoorn (NL), asklonn (NO), klon jesionolistny, jesioklon (PL), asklonn (SE).

/pdf/nobanis-invasive-alien-species-fact-sheet-2w2t03ah18.pdf

NOBANIS -Invasive Alien Species Fact Sheet

Spatial and temporal variability of streambed hydraulic conductivity in West Bear Creek, North Carolina, USA

Beaver (Castor canadensis) mitigate the effects of climate on the area of open water in boreal wetlands in western Canada

Billions of dollars are being spent in the United States to restore rivers to a desired, yet often unknown, reference condition. In lieu of a known reference, practitioners typically assume the paradigm of a connected watercourse. Geological and ecological processes, however, create patchy and discontinuous fluvial systems. One of these processes, dam building by North American beavers (Castor canadensis), generated discontinuities throughout precolonial river systems of northern North America. Under modern conditions, beaver dams create dynamic sequences of ponds and wet meadows among free-flowing segments. One beaver impoundment alone can exceed 1000 meters along the river, flood the valley laterally, and fundamentally alter biogeochemical cycles and ecological structures. In this article, we use hierarchical patch dynamics to investigate beaver-mediated discontinuity across spatial and temporal scales. We then use this conceptual model to generate testable hypotheses addressing channel geomorphology, n...

/pdf/the-river-discontinuum-applying-beaver-modifications-to-4awbeoit0i.pdf

The River Discontinuum: Applying Beaver Modifications to Baseline Conditions for Restoration of Forested Headwaters

/pdf/natural-vs-anthropogenic-streams-in-europe-history-ecology-2tasuefx10.pdf

Natural vs anthropogenic streams in Europe: History, ecology and implications for restoration, river-rewilding and riverine ecosystem services

The genus Castor comprises two species: the Eurasian beaver Castor fibre , and the North American beaver Castor canadensis . Both species suffered from overexploitation, but have seen a revival since the 1920s due to increased protection and reintroduction programmes. Increases in the populations and distributions of species that are able to modify ecosystems have generated much scientific interest. Here we review the available literature concerning the possible ecological impact of beaver species in the Old and New World. 2. Beavers, being ecosystem engineers, are among the few species besides humans that can significantly change the geomorphology, and consequently the hydrological characteristics and biotic properties of the landscape. In so doing, beavers increase heterogeneity, and habitat and species diversity at the landscape scale. Beaver foraging also has a considerable impact on the course of ecological succession, species composition and structure of plant commu- nities, making them a good example of ecologically dominant species (e.g. keystone species). 3. Nevertheless, the strength of beavers' impact varies from site to site, depending on the geographical location, relief and the impounded habitat type. Consequently, they may not be significant controlling agents of the ecosystem in all parts of their distribution, but have strong interactions only under certain circumstances. We suggest that beavers can create important management opportunities in the Holarctic, and this review will help land man- agers determine the likely outcome of beaver activity.

/pdf/ecological-impact-of-beavers-castor-fiber-and-castor-4vncs5wi7u.pdf

Orsolya Bozsér

Papers

Ecological impact of beavers Castor fiber and Castor canadensis and their ability to modify ecosystems