scholarly journals Climate and landscape drive the pace and pattern of conifer encroachment into subalpine meadows

2017 ◽  
Vol 27 (6) ◽  
pp. 1876-1887 ◽  
Author(s):  
Kaitlin C. Lubetkin ◽  
Anthony LeRoy Westerling ◽  
Lara M. Kueppers
Keyword(s):  
Subalpine Meadows ◽  
Conifer Encroachment

scholarly journals Conifer Establishment and Encroachment on Subalpine Meadows around Mt. Baker, WA, USA

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1390
Author(s):  
Ben Hagedorn ◽  
Aquila Flower
Keyword(s):  
20Th Century ◽  
Pacific Northwest ◽  
Cross Sections ◽  
Seedling Establishment ◽  
Strongly Correlated ◽  
Subalpine Meadows ◽  
Mountainous Regions ◽  
Conifer Encroachment ◽  
The Pacific ◽  
Conifer Seedling

The subalpine ecotone is experiencing significant changes in habitat availability and connectivity as a result of climate change. The conversion of meadow habitats to forests has been observed in many mountainous regions. Rates of conifer encroachment into meadows appears to have increased in the 20th century, but the patterns of conifer establishment seem highly variable over both space and time. To understand how and why these changes vary temporally and spatially in the Pacific Northwest, we collected cross-sections and whorl counts from conifers along four transects in subalpine meadows around Mt. Baker, Washington. We quantified the relationships between temporal patterns of conifer establishment and a suite of climate variables, and between spatial patterns of conifer density and microsite characteristics. Our results show that establishment occurred in pulses throughout the 20th century, with greater establishment on drier sites during periods of greater precipitation, and greater establishment on wetter sites during periods of higher temperatures. We found that April precipitation and September temperature are particularly strongly correlated with establishment rates, suggesting that the best conditions for conifer seedling establishment occur in years with the warmth and soil moisture needed for the growing season to start earlier or last longer. Within individual meadows, conifer seedling establishment was greater on convex surfaces and in areas with a higher percentage of Vaccinium cover. Our findings at Mt. Baker show that periods of conifer establishment occurred somewhat synchronously across multiple mountains in the region, but we also identified distinct spatial and temporal differences linked to local site conditions.

scholarly journals Net Primary Productivity of Subalpine Meadows in Yosemite National Park in Relation to Climate Variability

2013 ◽  
Vol 73 (4) ◽  
pp. 409-418 ◽  
Author(s):  
Peggy E. Moore ◽  
Jan W. van Wagtendonk ◽  
Julie L. Yee ◽  
Mitchel P. McClaran ◽  
David N. Cole ◽  
...  
Keyword(s):  
Climate Variability ◽  
Primary Productivity ◽  
National Park ◽  
Net Primary Productivity ◽  
Yosemite National Park ◽  
Subalpine Meadows

scholarly journals The effects of tourism on species diversity of subalpine meadows in Dong

2002 ◽  
Vol 10 (2) ◽  
pp. 189-195
Author(s):  
Xianming Gao ◽  
CHEN Ling-Zhi ◽  
LI Di-Qiang ◽  
MA Ke-Ping ◽  
Keyword(s):  
Species Diversity ◽  
Subalpine Meadows

scholarly journals A Landscape Approach to Aspen Restoration: Understanding the Role of Biophysical Setting in Aspen Community Dynamics

2002 ◽  
Vol 26 ◽  
pp. 97-102
Author(s):  
Kathryn Brown ◽  
Andrew Hansen ◽  
Robert Keane ◽  
Lisa Graumlich
Keyword(s):  
Populus Tremuloides ◽  
Community Dynamics ◽  
Rocky Mountain ◽  
Small Sample ◽  
Quaking Aspen ◽  
Climatic Fluctuations ◽  
Conifer Encroachment ◽  
Considerable Debate ◽  
Fire Exclusion

Considerable debate surrounds the persistence of quaking aspen (Populus tremuloides) communities in western North America. Loss of aspen cover has been documented in several studies in various Rocky Mountain ecosystems (Loope and Gruel 1973; Romme et al. 1995; Renkin and Despain 1996; Wirth et al. 1996; Baker et al. 1997; Kay 1997; Bartos and Campbell 1998; White et al. 1998; Gallant et al. 2003). Explanations for loss of aspen include conifer encroachment, fire exclusion, herbivory, and climatic fluctuations (Loope and Gruell 1973; Mueggler 1985; Bartos et al. 1994; Romme et al. 1995; Kay 1997; White et al. 1998). However, many studies documenting aspen decline have been geographically limited or based on a small sample of subjectively chosen stands (Barnett and Stohlgren 2001; Hessl 2002; Kaye et al. 2003).

Vegetation responses to conifer encroachment in a western Cascade meadow: a chronosequence approach

2007 ◽  
Vol 85 (3) ◽  
pp. 285-298 ◽  
Author(s):  
Ryan D. Haugo ◽  
Charles B. Halpern
Keyword(s):  
Forest Structure ◽  
Vegetation Change ◽  
Light Availability ◽  
Basal Area ◽  
Tree Age ◽  
Long Term Effects ◽  
Conifer Encroachment ◽  
Forest Herbs ◽  
Meadow Species ◽  
Chronosequence Approach

Conifer invasion of mountain meadows is pervasive in western North America, but its consequences for plant composition and diversity have not been studied. We used a chronosequence approach to reconstruct temporal patterns of vegetation change in response to ~200 years of conifer encroachment of a dry, montane meadow in the western Cascade Range, Oregon. Tree age distributions, forest structure, light, and vegetation composition were determined for three hundred and fifty-six 10 m × 10 m samples representing a gradient from open meadow to old forest (>90 years). Nonmetric multidimensional scaling revealed strong turnover in species composition from open meadow to old forest. Ordination axes were highly correlated with light availability and density/basal area of encroaching grand fir, Abies grandis (Dougl. ex D. Don) Lindl., and lodgepole pine, Pinus contorta Dougl. ex Loud. Cover of meadow species declined steeply with establishment of A. grandis ; richness declined more gradually and extirpations of meadow species were rare. Forest herbs colonized within two decades of tree establishment and within 60–80 years dominated the understory flora. In contrast with meadow species, changes in richness and cover of forest herbs were weakly related to changes in forest structure. Rapid replacement of meadow by forest species and long-term effects of trees on soils may limit potential for restoration of these unique habitats.

scholarly journals Actual evapotranspiration of subalpine meadows in the Qilian Mountains, Northwest China

2019 ◽  
Vol 11 (3) ◽  
pp. 371-384
Author(s):  
Yunfei Gao ◽  
Chuanyan Zhao ◽  
Muhammad W. Ashiq ◽  
Qingtao Wang ◽  
Zhanlei Rong ◽  
...  
Keyword(s):  
Northwest China ◽  
Qilian Mountains ◽  
Actual Evapotranspiration ◽  
Subalpine Meadows ◽  
The Qilian Mountains

Seed banks trigger ecological resilience in subalpine meadows abandoned after arable farming on the Tibetan Plateau

2019 ◽  
Vol 29 (7) ◽  
Author(s):  
Miaojun Ma ◽  
Carol C. Baskin ◽  
Wenjin Li ◽  
Yunpeng Zhao ◽  
Yin Zhao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Seed Banks ◽  
Ecological Resilience ◽  
The Tibetan Plateau ◽  
Subalpine Meadows ◽  
Arable Farming

scholarly journals Fire Exclusion Destroys Habitats for At-Risk Species in a British Columbia Protected Area

Fire ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 48
Author(s):  
Kira M. Hoffman ◽  
Sara B. Wickham ◽  
William S. McInnes ◽  
Brian M. Starzomski
Keyword(s):  
British Columbia ◽  
Fire History ◽  
Prescribed Burning ◽  
Douglas Fir ◽  
Conifer Encroachment ◽  
Oak Trees ◽  
Composition And Structure ◽  
Fire Exclusion ◽  
History Of

Fire exclusion and suppression has altered the composition and structure of Garry oak and associated ecosystems in British Columbia. The absence of frequent low severity ground fires has been one of the main contributors to dense patches of non-native grasses, shrubs, and encroaching Douglas-fir trees in historical Garry oak dominated meadows. This case study uses remote sensing and dendrochronology to reconstruct the stand dynamics and long-term fire history of a Garry oak meadow situated within Helliwell Provincial Park located on Hornby Island, British Columbia. The Garry oak habitat in Helliwell Park has decreased by 50% since 1950 due to conifer encroachment. Lower densities and mortalities of Garry oak trees were associated with the presence of overstory Douglas-fir trees. To slow conifer encroachment into the remaining Garry oak meadows, we recommend that mechanical thinning of Douglas-fir be followed by a prescribed burning program. Reintroducing fire to Garry oak ecosystems can restore and maintain populations of plants, mammals, and insects that rely on these fire resilient habitats.

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