Fates of Added Nitrogen in Freshwater Arctic Wetlands Grazed by Snow Geese: The Role of Mosses

2002 ◽  
Vol 34 (2) ◽  
pp. 219-225 ◽  
Author(s):  
Peter M. Kotanen
Keyword(s):  
Snow Geese ◽  
Arctic Wetlands

Fates of Added Nitrogen in Freshwater Arctic Wetlands Grazed by Snow Geese: The Role of Mosses

2002 ◽  
Vol 34 (2) ◽  
pp. 219 ◽  
Author(s):  
Peter M. Kotanen
Keyword(s):  
Snow Geese ◽  
Arctic Wetlands

The role of lesser snow geese as nitrogen processors in a sub-arctic salt marsh

Oecologia ◽  
1989 ◽  
Vol 79 (1) ◽  
pp. 23-29 ◽  
Author(s):  
R. W. Ruess ◽  
D. S. Hik ◽  
R. L. Jefferies
Keyword(s):  
Salt Marsh ◽  
Snow Geese ◽  
Lesser Snow Geese

The role of phenolic compounds and nutrients in determining food preference in greater snow geese

Oecologia ◽  
1990 ◽  
Vol 84 (4) ◽  
pp. 553-558 ◽  
Author(s):  
Gilles Gauthier ◽  
Jean Bédard
Keyword(s):  
Phenolic Compounds ◽  
Food Preference ◽  
Snow Geese

The palatability of Arctic willow for greater snow geese: the role of nutrients and deterring factors

Oecologia ◽  
1995 ◽  
Vol 103 (3) ◽  
pp. 390-392 ◽  
Author(s):  
Gilles Gauthier ◽  
R. John Hughes
Keyword(s):  
Snow Geese

The embarrassment of riches: agricultural food subsidies, high goose numbers, and loss of Arctic wetlands – a continuing saga

2004 ◽  
Vol 11 (4) ◽  
pp. 193-232 ◽  
Author(s):  
R L Jefferies ◽  
R F Rockwell ◽  
K F Abraham
Keyword(s):  
Canadian Arctic ◽  
Agricultural Landscapes ◽  
The Arctic ◽  
Coastal Marshes ◽  
Migratory Connectivity ◽  
Snow Geese ◽  
Lesser Snow Geese ◽  
Breeding Grounds ◽  
Arctic Wetlands ◽  
Agricultural Food

Agriculture has provided a nutritional subsidy to the Anatidae (swans, geese, ducks), which has affected their trophic relationships and the Arctic wetlands where they breed. The Mid-Continent Population of lesser snow geese, which breeds in the Canadian Arctic and which traditionally wintered in the coastal marshes of the Gulf States, now feeds in agricultural landscapes. The geometric growth of this population since 1970 is coincident with increased application of nitrogen to farmland and high crop yields. Widespread availability of agricultural foods allows the birds to meet much of their energy demand for migration and reproduction. Their migration conforms to a stepping stone model linked to land use, but feeding also takes place upon arrival on the Arctic breeding grounds. High bird numbers have dramatically affected coastal marshes of the Canadian Arctic. Foraging has produced alternative stable states characterized by sward destruction and near irreversible changes in soil properties of exposed sediments. Locally, this loss of resilience has adversely affected different groups of organisms, resulting in an apparent trophic cascade. A spring hunt was introduced in 1999 in an attempt to check population growth. The current annual cull is now thought to be higher than the replacement rate. Much of the decline of the Mid-Continent Population is probably linked to shooting, but the harassment of birds that fail to acquire sufficient food for reproduction may contribute. The agricultural food subsidy has led to a mismatch between this avian herbivore and its environment — a consequence of migratory connectivity that links wintering and breeding grounds. Key words: agricultural crops, lesser snow geese, migratory connectivity, Arctic coastal marshes, grubbing, hypersalinity, the spring hunt.

Effects of labile carbon on anaerobic decomposition processes in permafrost wetlands

2021 ◽  
Author(s):  
Maija E. Marushchak ◽  
Hannu Nykänen ◽  
Jukka Pumpanen ◽  
A. Britta K. Sannel ◽  
Lena Ström ◽  
...  
Keyword(s):  
Active Layer ◽  
Soil Incubation ◽  
Labile Carbon ◽  
Soil Layers ◽  
Anaerobic Decomposition ◽  
Permafrost Thaw ◽  
Ground Collapse ◽  
Decomposition Processes ◽  
Arctic Wetlands

<p>Climate warming and permafrost thaw are exposing the large carbon (C) pools of northern wetlands to enhanced decomposition, potentially increasing the release of the greenhouse gases carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>). Permafrost thaw is usually associated with changes in hydrology and vegetation: Ground collapse leads to the formation of new, productive thermokarst wetlands, and active layer deepening allows plant roots to penetrate to deeper soil layers. These processes promote interaction between old permafrost carbon and recent plant-derived carbon, but the effect of this interaction on anaerobic decomposition processes is poorly known.</p><p>Here, we report the preliminary results of a 1+-year-long soil incubation experiment where we investigated the role of fresh organics on anaerobic decomposition in arctic wetlands. We sampled mineral subsoil of Greenlandic wetland sites and the active layer and permafrost peat in a Swedish palsa mire, and incubated them with and without repeated amendments of <sup>13</sup>C enriched glucose and cellulose. We determined the rate and isotopic composition of CO<sub>2</sub> and CH<sub>4</sub> with an isotopic laser, and estimated the contribution of soil organic matter decomposition vs. added carbon to the total C gas release. These results represent new understanding on how plant-derived organics change the magnitude and composition of C gas, thus affecting the climatic feedbacks from permafrost wetland C pool.</p>

Deterring arctic fox predation: the role of parental nest attendance by lesser snow geese

2001 ◽  
Vol 79 (5) ◽  
pp. 861-866 ◽  
Author(s):  
Gustaf Samelius ◽  
Ray T Alisauskas
Keyword(s):  
Arctic Fox ◽  
Nest Attendance ◽  
Alopex Lagopus ◽  
Chen Caerulescens ◽  
Banks Island ◽  
Snow Geese ◽  
Lesser Snow Geese ◽  
Arctic Foxes ◽  
Chen Caerulescens Caerulescens

High parental attendance at nests can improve nesting performance in birds by shortening the nesting period and by deterring predators that do not force birds off of nests. We examined how parental nest attendance by lesser snow geese (Chen caerulescens caerulescens) affected (i) foraging behaviours of arctic foxes (Alopex lagopus) and (ii) egg loss by geese exposed to arctic foxes at a large goose colony on Banks Island, N.W.T., Canada. Unattended nests and nests attended by single females suffered much greater egg loss to foxes than nests attended by paired geese. This resulted from foxes attacking unattended nests and single females far more frequently than expected by chance and from geese associated with such nests offering little or no resistance to foxes. Paired geese, in contrast, were avoided by foxes and also showed greater resistance to foxes than single females and unattended nests. Nest attendance by male geese can therefore be important in reducing egg loss to arctic foxes, but it may play an even greater role in reducing egg loss to arctic foxes in small colonies or during colony formation, when the ratio of predators to nests is generally high.

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor

Role of the allergist in diagnosis and management of patients with uveitis

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre
Keyword(s):  
Diagnosis And Management
Sign in / Sign up

Export Citation Format

Share Document