Changes in vegetative cover on Western Arctic Herd winter range from 1981 to 2005: potential effects of grazing and climate change

Kyle Joly; Randi R. Jandt; Cynthia R. Meyers; Martha J. Cole

doi:10.7557/2.27.4.345

Changes in vegetative cover on Western Arctic Herd winter range from 1981 to 2005: potential effects of grazing and climate change

Rangifer ◽

10.7557/2.27.4.345 ◽

2007 ◽

Vol 27 (4) ◽

pp. 199 ◽

Cited By ~ 24

Author(s):

Kyle Joly ◽

Randi R. Jandt ◽

Cynthia R. Meyers ◽

Martha J. Cole

Keyword(s):

Climate Change ◽

Rangifer Tarandus ◽

Global Climate ◽

Shrub Cover ◽

Population Declines ◽

Vegetative Cover ◽

Habitat Condition ◽

Winter Range ◽

Lichen Cover ◽

Western Arctic

The population of the Western Arctic Herd, estimated at 490 000 caribou (Rangifer tarandus granti) in 2003, is at its highest level in 30 years. Twenty permanent range transects were established in the winter range of the Western Arctic Herd in 1981 to assess the impacts of grazing. These transects were revisited in 1995 and 1996 (1995/96). Only 18 of the transects were re-located, so an additional 7 transects were established in 1996. In 2005, all 25 remaining transects were revisited. Lichen coverage dropped by a relative 45.1% between 1981 and 1995/96 and by an additional relative 25.6% between 1995/96 and 2005. There was a significant decline in primary forage lichens between 1995/96 and 2005. Caribou use was greater in areas with high lichen abundance. Graminoid cover increased by a relative 118.4% from 1981 to 1995/96 and again by a relative 26.1% from 1995/96 to 2005. Shrub cover increased during the study whereas forb cover declined. The decline in lichen abundance on the winter range of the Western Arctic Herd over 24 years is an index of caribou habitat condition. The observed changes in vegetation cover can be attributed to caribou grazing, fire, and possibly global climate change. Continued declines in lichen cover could lead to population declines within the herd, range shifts, or both.

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Historical species losses in bumblebee evolution

Biology Letters ◽

10.1098/rsbl.2014.1049 ◽

2015 ◽

Vol 11 (3) ◽

pp. 20141049 ◽

Cited By ~ 11

Author(s):

Fabien L. Condamine ◽

Heather M. Hines

Keyword(s):

Climate Change ◽

Environmental Changes ◽

Global Climate ◽

Global Changes ◽

Species Loss ◽

Population Declines ◽

Modern Species ◽

Dominant Feature ◽

History Of ◽

Species Dynamics

Investigating how species coped with past environmental changes informs how modern species might face human-induced global changes, notably via the study of historical extinction, a dominant feature that has shaped current biodiversity patterns. The genus Bombus , which comprises 250 mostly cold-adapted species, is an iconic insect group sensitive to current global changes. Through a combination of habitat loss, pathogens and climate change, bumblebees have experienced major population declines, and several species are threatened with extinction. Using a time-calibrated tree of Bombus , we analyse their diversification dynamics and test hypotheses about the role of extinction during major environmental changes in their evolutionary history. These analyses support a history of fluctuating species dynamics with two periods of historical species loss in bumblebees. Dating estimates gauge that one of these events started after the middle Miocene climatic optimum and one during the early Pliocene. Both periods are coincident with global climate change that may have extirpated Bombus species. Interestingly, bumblebees experienced high diversification rates during the Plio-Pleistocene glaciations. We also found evidence for a major species loss in the past one million years that may be continuing today.

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Phenolic Responses of Mountain Crowberry (Empetrum nigrum ssp. hermaphroditum) to Global Climate Change are Compound Specific and Depend on Grazing by Reindeer (Rangifer tarandus)

Journal of Chemical Ecology ◽

10.1007/s10886-013-0367-z ◽

2013 ◽

Vol 39 (11-12) ◽

pp. 1390-1399 ◽

Cited By ~ 11

Author(s):

Maria Väisänen ◽

Françoise Martz ◽

Elina Kaarlejärvi ◽

Riitta Julkunen-Tiitto ◽

Sari Stark

Keyword(s):

Climate Change ◽

Global Climate Change ◽

Rangifer Tarandus ◽

Global Climate ◽

Empetrum Nigrum

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Climate change impacts and vegetation response on the island of Madagascar

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2004.1476 ◽

2005 ◽

Vol 363 (1826) ◽

pp. 55-59 ◽

Cited By ~ 46

Author(s):

J. Carter Ingram ◽

Terence P. Dawson

Keyword(s):

Climate Change ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Southern Oscillation ◽

Global Climate ◽

Hot Spot ◽

Vegetative Cover ◽

Vegetation Response ◽

Natural Habitats ◽

Strong Negative Correlation

The island of Madagascar has been labelled the world's number one conservation ‘hot spot’ because of increasing anthropogenic degradation of its natural habitats, which support a high level of species endemism. However, climatic phenomena may also have a significant impact upon the island's flora and fauna. An analysis of 18 years of monthly satellite images from the National Oceanographic and Atmospheric Administration's (NOAA) Advanced Very High Resolution Radiometer (AVHRR) have demonstrated that there is a dynamic pattern in Madagascar's vegetative cover both annually and seasonally throughout 1982–1999. Over interannual time–scales, we show that this vegetation response, calculated using the normalized difference vegetation index (NDVI), has a strong negative correlation with the El Niño Southern Oscillation (ENSO), which can be attributable to drought events and associated wildfires. Global climate change is predicted to increase the frequency of the ENSO phenomenon, resulting in further decline of Madagascar's natural environment.

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Two caribou mortality events in Northwest Alaska: possible causes and management implications

Rangifer ◽

10.7557/2.25.4.1769 ◽

2005 ◽

Vol 25 (4) ◽

pp. 37 ◽

Cited By ~ 5

Author(s):

Jim Dau

Keyword(s):

High Mortality ◽

Rangifer Tarandus ◽

Ambient Air ◽

Management Implications ◽

Severe Storms ◽

Ovibos Moschatus ◽

Winter Range ◽

Local Residents ◽

Western Arctic ◽

Snow Conditions

During fall and winter 1994—1995 and winter 1999—2000, caribou (Rangifer tarandus granti) from the Western Arctic Herd experienced high, localized mortality in northwest Alaska near Cape Thompson. Substantial numbers of caribou wintered in this area during 1986—1987, 2001—2002, and 2002—2003 without suffering high mortality. During the 1994—1995 event, 2000 to 3000 caribou died out of roughly 10 000 that wintered in this area. About 4000 caribou perished out of approximately 20 000 that wintered here during 1999—2000. During both mortality events, gross characteristics and tissue analyses indicated caribou in this area were malnourished. Weather near Cape Thompson during winter 1994—1995 was colder, windier, and had more snow than other years when caribou wintered in this area; in contrast, conditions during 1999—2000 were not unusually severe. Additionally, Cape Thompson experienced 2—5 occurrences of severe conditions during winter 1994—1995 while 1999—2000 experienced only 1 such occurrence at most. Several indicators suggested severe storms killed some caribou before starvation was fatal. Cape Thompson consistently experienced higher wind, lower ambient air temperature, and shallower snow cover than other portions of winter range used by this herd. Unlike years when caribou wintered in this area without experiencing high mortality, caribou were in relatively poor body condition during the autumn that preceded each die-off. Although these mortality events were inconsequential to size of this caribou herd, they raised local residents' concerns that contaminants had poisoned caribou and possibly jeopardized human health. Muskoxen (Ovibos moschatus) in this area were not affected by weather or snow conditions during either caribou mortality event.

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