The Holocene vegetation history of Isle Royale National Park, Michigan, U.S.A.

2003 ◽  
Vol 33 (6) ◽  
pp. 1144-1166 ◽  
Author(s):  
Robyn Flakne
Keyword(s):  
National Park ◽  
Vegetation History ◽  
Sediment Cores ◽  
Forest Composition ◽  
Isle Royale ◽  
Main Island ◽  
Isle Royale National Park ◽  
Forest Lake ◽  
History Of ◽  
Lake Ojibway

A vegetation history for Isle Royale National Park, Michigan, U.S.A., is reconstructed using pollen and spores extracted from two lake sediment cores. Lily Lake is on the southwestern end of the main island of Isle Royale surrounded by northern hardwoods forest. Lake Ojibway is on the northeastern end of the main island surrounded by boreal forest. Pollen and spore records were analyzed using pollen percentage diagrams, nonmetric multidimensional scaling ordination, and modern analog analysis. Squared chord distances for temporally paired subsamples from each site were calculated to determine palynological dissimilarities between the sites through time. These analyses revealed an overall vegetation history that is consistent with other regional reconstructions. High percentages of spruce pollen, indicating a cool climate, are present in the early Holocene, whereas high percentages of pine pollen, indicating a dry climate, occur in the mid-Holocene. The pollen records from the two sites diverge with increased precipitation during the late Holocene. At this time, birch-dominated forest is established near Lily Lake on till-derived soils. At Lake Ojibway, a mixed birch, pine, spruce, and fir forest is established on bedrock-derived soils. The divergence in forest composition is most pronounced within the last 500 years, and this divergence is tentatively attributed to the response of taxa on different substrates to increasing precipitation. Other possible explanations for the recent divergence include changing microclimates or disturbance regimes.

scholarly journals The Moose of Isle Royale: An Unnatural Condition?

2015 ◽  
Author(s):  
Samuel V Scarpino ◽  
Rafael F Guerrero ◽  
Philip V Scarpino
Keyword(s):  
National Park ◽  
Lake Superior ◽  
Local Extinction ◽  
Isle Royale ◽  
Predator Prey ◽  
Isle Royale National Park ◽  
Population Crash ◽  
History Of

The now iconic moose of Isle Royale National Park arrived on the island sometime between 1910 and 1915. Prior to that period there is no evidence of moose in either naturalist reports or in the archaeological history of the island. Early naturalists—while observing the moose during their first 20 years on the island—noted both their dramatic expansion, and equally dramatic population crash in the 1930s, see Figure 1. Around 1950, and just as the moose were rebounding, wolves crossed a frozen Lake Superior and began what is now one of our most emblematic predator/prey systems. Recently, the wolves on Isle Royale appear headed for local extinction. Calls to repopulate the island have renewed the vigorous debate surrounding what is and what is not wild about Isle Royale.

Moose Browsing and Soil Fertility in the Boreal Forests of Isle Royale National Park

Ecology ◽  
1993 ◽  
Vol 74 (2) ◽  
pp. 467-480 ◽  
Author(s):  
J. Pastor ◽  
B. Dewey ◽  
R. J. Naiman ◽  
P. F. McInnes ◽  
Y. Cohen
Keyword(s):  
Soil Fertility ◽  
Boreal Forests ◽  
National Park ◽  
Isle Royale ◽  
Isle Royale National Park ◽  
Moose Browsing

A palynological study of postglacial vegetation changes in the University Research Forest, southwestern British Columbia

1973 ◽  
Vol 51 (11) ◽  
pp. 2085-2103 ◽  
Author(s):  
Rolf W. Mathewes
Keyword(s):  
British Columbia ◽  
Pinus Contorta ◽  
Vegetation Change ◽  
Vegetation History ◽  
Sediment Cores ◽  
Silty Clay ◽  
Pollen Diagram ◽  
History Of ◽  
Palynological Study ◽  
The University

The postglacial vegetation history of the University of British Columbia Research Forest was investigated using percentage and absolute pollen analysis, macrofossil analysis, and radiocarbon dating. A marine silty clay deposit records the oldest (12 690 ± 190 years before present (B.P.)) assemblage of terrestrial plant remains so far recovered from the postglacial of south-coastal British Columbia. Lodge-pole pine (Pinus contorta) dominated this early vegetation, although some Abies, Picea, Alnus, and herbs were also present. Sediment cores from two lakes were also studied. The older is Marion Lake, where five pollen assemblage zones are recognized, beginning with a previously undescribed assemblage of Pinus contorta, Salix, and Shepherdia in clay older than 12 350 ± 190 B.P. The pollen diagram from Surprise Lake (11 230 ± 230 B.P.) is divided into three pollen zones which show the same major trends of vegetation change as the Marion Lake diagram.The first report of the postglacial vegetation history of cedar (Thuja and perhaps Chamaecyparis) in southwestern British Columbia is presented from pollen and macrofossil analyses.At about 10 500 B.P. in both lakes, pollen of Douglas fir (Pseudotsuga menziesii) began a rapid increase, probably in response to climatic amelioration. The palynological evidence, supported by well-preserved bryophyte subfossils, suggests that humid coastal conditions have prevailed in the study area since about 10 500 B.P., with virtually no evidence for a classical Hypsithermal interval between 8500 B.P. and 3000 B.P.

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