scholarly journals Beavers

2017 ◽  
Author(s):  
Jimmy D. Taylor ◽  
Greg K. Yarrow ◽  
James E. Miller

The American beaver (Castor canadensis) is known as an “ecosystem engineer” because of the benefits their dams provide to biological diversity and ecosystem function. It also is considered a “keystone species” because of its ability to transform its environment, creating new habitats upon which other species depend. Despite the many positive benefits beavers provide through foraging and dam building, beavers also create conflict with people when their activities cause damage. The focus of this publication is to provide basic information on beaver ecology, damage, and management.

1998 ◽  
Vol 22 (2) ◽  
pp. 167-189 ◽  
Author(s):  
Angela M. Gurnell

A characteristic of beaver ecology is their ability to build dams and, thus, to modify the landscape to increase its suitability for their occupation. This ability gives beaver great significance as a geomorphic agent. In order to review the hydrogeomorphological effects of beaver dam-building activity, this article places a context on the likely distribution and magnitude of beaver activity by considering the spatial and temporal variability of distributions of beaver and the habitat characteristics which might favour the establishment of substantial beaver populations. A description is then given of the nature and potential dimensions of instream structures built by beaver and the environmental conditions under which dam building has been observed to occur. The hydrogeomorphological impact of dam building is then appraised both locally and at the landscape scale, illustrating the very significant process modification caused by beaver. While the European beaver, Castor fiber, is the main focus of this review, it necessarily draws extensively on the much larger literature concerning the North American beaver (Castor canadensis).


2021 ◽  
Vol 2 ◽  
Author(s):  
Jonathan Q. Richmond ◽  
Camm C. Swift ◽  
Thomas A. Wake ◽  
Cheryl S. Brehme ◽  
Kristine L. Preston ◽  
...  

Non-native species having high per capita impacts in invaded communities are those that modulate resource availability and alter disturbance regimes in ways that are biologically incompatible with the native biota. In areas where it has been introduced by humans, American beaver (Castor canadensis) is an iconic example of such species due to its capacity to alter trophic dynamics of entire ecosystems and create new invasional pathways for other non-native species. The species is problematic in several watersheds within the Southern California-Northern Baja California Coast Ecoregion, a recognized hotspot of biodiversity, due to its ability to modify habitat in ways that favor invasive predators and competitors over the region's native species and habitat. Beaver was deliberately introduced across California in the mid-1900s and generally accepted as non-native to the region up to the early 2000s; however, articles promoting the idea that beaver may be a natural resident have gained traction in recent years, due in large part to the species' charismatic nature rather than by presentation of sound evidence. Here, we discuss the problems associated with beaver disturbance and its effects on conserving the region's native fauna and flora. We refute arguments underlying the claim that beaver is native to the region, and review paleontological, zooarchaeological, and historical survey data from renowned field biologists and naturalists over the past ~160 years to show that no evidence exists that beaver arrived by any means other than deliberate human introduction. Managing this ecosystem engineer has potential to reduce the richness and abundance of other non-native species because the novel, engineered habitat now supporting these species would diminish in beaver-occupied watersheds. At the same time, hydrologic functionality would shift toward more natural, ephemeral conditions that favor the regions' native species while suppressing the dominance of the most insidious invaders.


Author(s):  
Christer Brönmark ◽  
Lars-Anders Hansson

If biological interactions, such as competition and predation, have any effect on population dynamics, or if abiotic factors alone determine which organisms, how many of them do we see in a specific ecosystem, was for long a controversial question. This chapter aims at providing the basis for the understanding of biological interactions, as well as showing ample examples of how important those interactions are in shaping both population dynamics and ecosystem function of natural systems. In addition to the many examples, the reader is introduced to the history and the theoretical basis for biological interactions.


1997 ◽  
Vol 34 (1) ◽  
pp. 268
Author(s):  
P. D. Carey ◽  
P. M. Vitousek ◽  
L. L. Loope ◽  
J. Adsersen

Botany ◽  
2009 ◽  
Vol 87 (1) ◽  
pp. 22-25 ◽  
Author(s):  
M. E. Ostry ◽  
G. Laflamme

Forest health is described and perceived in different ways by the general public, land owners, managers, politicians, and scientists, depending on their values and objectives. Native tree pathogens and diseases are often associated with negative impacts even though damage is limited or not widespread. Too often, the concepts of tree health and forest health are used interchangeably and are not related to scale. Similar to fire, occurrences of disease outbreaks focus on the negative effects. However, native pathogens often exist in equilibrium with natural forest communities so their critical ecological roles are not easily discernible. Examined holistically, native fungi and diseases, dead and dying trees, and the many complex ecological interactions among them provide valuable benefits that ultimately contribute to sustainable, healthy forest ecosystems.


2017 ◽  
Vol 130 (4) ◽  
pp. 332 ◽  
Author(s):  
Thomas S Jung ◽  
Jay Frandsen ◽  
Danny C Gordon ◽  
David H Mossop

A consequence of rapid global warming has been the shrubification (increase in shrub abundance, cover, and biomass) of arctic and alpine tundra ecosystems. Shrubification is likely a key driver of predicted and observed changes in the biodiversity of the Arctic. The American Beaver (Castor canadensis) has a vast distributional range, covering most of north America below the tree line; however, it has not been recorded in tundra habitat of the Beaufort Coastal Plain of Yukon and Alaska. in 2015, we observed a beaver dam, lodge, and winter food cache on the Babbage River in Ivvavik National Park, Yukon, Canada. Local Inuvialuit hunters first observed beavers on two rivers immediately east of the Babbage River in 2008 and 2009. Together, these are the first observations of beavers on the Beaufort Coastal Plain and indicate initial attempts at colonization. Colonization of the Beaufort Coastal Plain by beavers may have been facilitated by shrubification of river valleys on the tundra of northern Yukon and adjacent Alaska, which is a consequence of rapid climate warming in the western Arctic.


2020 ◽  
Vol 134 (1) ◽  
pp. 45-51
Author(s):  
Juliana Balluffi-Fry ◽  
Liane B. Nowell ◽  
Murray M. Humphries

The feeding habits of generalist predators often vary among populations and regions. For example, Coyote (Canis latrans), which is a generalist predator distributed across North America, occupies a wide range of habitats and has a highly varied diet. In this observational study, we quantified the presence of mammalian prey items in 50 Eastern Coyote (Canis latrans var.) scats collected in late spring and summer in a private game reserve in southwestern Quebec. Nearly all scats contained hair of White-tailed Deer (Odocoileus virginianus; 44%), Moose (Alces americanus; 38%), or American Beaver (Castor canadensis; 38%). Although all three species are known to be consumed by coyotes, such a high proportion of Moose and White-tailed Deer simultaneously occurring in the diet of coyotes has not been previously reported. The uniqueness of the study area, with its relatively high abundance of all three prey species, may account for the uniqueness of the diet of Eastern Coyotes living there.


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