Vegetation patterns and environmental gradients in coastal meadows on the Yukon–Kuskokwim delta, Alaska

Kincheloe, Karen L.; Stehn, Robert A.

doi:10.1139/b91-205

Cited by 57 publications

(32 citation statements)

References 22 publications

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“…This region is a coastal salt marsh maintained by large flooding events and daily influxes of brackish water from the numerous rivers and sloughs permeating the landscape (Kincheloe and Stehn, 1991). Species diversity of vegetation is low, and continuous meadows of C. ramenskii and C. rariflora dominate the landscape (Babcock and Ely, 1994;Jorgenson, 2000).…”

Section: Study Areamentioning

confidence: 99%

“…Species diversity of vegetation is low, and continuous meadows of C. ramenskii and C. rariflora dominate the landscape (Babcock and Ely, 1994;Jorgenson, 2000). Along the interface of C. ramenskii meadows and also along coastal margins, riparian mudflats, and pond margins are patchily distributed swards of C. subspathacea (Kincheloe and Stehn, 1991;Jorgenson, 2000), which foraging geese prefer because of its high nutrient content (Sedinger and Raveling, 1984;Laing and Raveling, 1993;Ruess et al, 1997). Grazing pressures on C. subspathacea are high (Person et al, 1998), and adult geese sometimes forage in the adjacent, less nutritious C. ramenskii community (Ruess et al, 1997).…”

Section: Study Areamentioning

confidence: 99%

“…In this paper, we use the term "grazing lawn" to refer both to C. subspathacea and to C. ramenskii that has reverted to a form indistinguishable from C. subspathacea. Other dominant habitats in this region include sloughlevee (consisting of Arctophila fulva, C. lyngbyaei, Deschampsia caespitosa, Elymus arenarius, Poa arctica, and Triglochin palustris) and uplands of Empetrum nigrum, Sphagnum spp., Betula nana, and Cladina rangiferina (Kincheloe and Stehn, 1991;Babcock and Ely, 1994;Jorgenson, 2000).…”

Section: Study Areamentioning

confidence: 99%

“…We chose a priori to limit habitats to eight categories, with the expectation that this would limit classification error yet still provide meaningful resolution. These categories were (1) grazing lawn (C. subspathacea and reverted C. ramenskii), (2) sedge meadow (primarily C. ramenskii and C. rariflora), (3) slough-levee (primarily Elymus arenarius, Poa arctica, and Deschampsia caespitosa), (4) upland (primarily Empetrum nigrum, Sphagnum spp., and Betula nana), (5) mud, (6) pond or lake, (7) river or slough, and (8) other (primarily pieces of driftwood; Kincheloe and Stehn, 1991;Babcock and Ely, 1994;Jorgenson, 2000). While we collected information on all eight categories, our objective was to present only availability of grazing lawns, as this habitat is most relevant to broods of emperor geese (Laing and Raveling, 1993;Schmutz, 2001;Schmutz and Laing, 2002).…”

Section: Sampling Videography Datamentioning

confidence: 99%

“…On the YKD, these grazing lawns range in size from 10 cm wide linear strips to 0.25 km 2 patches (Person et al, 1998). Previous efforts to quantify the availability of this food resource have used ground crews (Kincheloe and Stehn, 1991;Jorgenson, 2000) or a combination of ground crews and color infrared photos (Tande and Jennings, 1986;Babcock and Ely, 1994). However, applying these methods at a landscape level has proved prohibitively difficult because of the large time investment in sampling, the logistical challenges of working in a remote setting, and the high associated costs.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Using Videography to Quantify Landscape-Level Availability of Habitat for Grazers: An Example with Emperor Geese in Western Alaska

Lake

Lindberg²,

Schmutz³

et al. 2009

ARCTIC

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ABSTRACT. We present a videography approach to estimating large-scale availability of grazing lawns, an important food resource used by broods of emperor geese (Chen canagica) on the Yukon-Kuskokwim Delta, Alaska. Sampling was conducted in 1999Sampling was conducted in , 2003Sampling was conducted in , and 2004 at six locations that encompassed ~40% of the North American population of breeding emperor geese. We conducted ground truthing in 2003 and 2004 to estimate how accurately grazing lawn was classified. Overall, classification accuracy for grazing lawn and non-grazing lawn habitat was greater than 91%. Availability of grazing lawns was stable among years, but varied both among and within locations. Some locations have up to three times as much available grazing lawn, which in combination with densities of geese, likely represents dramatic variation in per capita food availability. Our results suggest that videography is a useful way to sample quickly across a large region and accurately identify fine-scale habitats. We present its use for estimating the availability of a preferred food resource for emperor geese, but the method could be applied to many other cases.

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Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Sampling Videography Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Using Videography to Quantify Landscape-Level Availability of Habitat for Grazers: An Example with Emperor Geese in Western Alaska

Lake

Lindberg²,

Schmutz³

et al. 2009

ARCTIC

View full text Add to dashboard Cite

show abstract

Interactions among vegetation, climate, and herbivory control greenhouse gas fluxes in a subarctic coastal wetland

et al. 2016

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High‐latitude ecosystems are experiencing the most rapid climate changes globally, and in many areas these changes are concurrent with shifts in patterns of herbivory. Individually, climate and herbivory are known to influence biosphere‐atmosphere greenhouse gas (GHG) exchange; however, the interactive effects of climate and herbivory in driving GHG fluxes have been poorly quantified, especially in coastal systems that support large populations of migratory waterfowl. We investigated the magnitude and the climatic and physical controls of GHG exchange within the Yukon‐Kuskokwim Delta in western Alaska across four distinct vegetation communities formed by herbivory and local microtopography. Net CO2 flux was greatest in the ungrazed Carex meadow community (3.97 ± 0.58 [SE] µmol CO2 m−2 s−1), but CH4 flux was greatest in the grazed community (14.00 ± 6.56 nmol CH4 m−2 s−1). The grazed community is also the only vegetation type where CH4 was a larger contributor than CO2 to overall GHG forcing. We found that vegetation community was an important predictor of CO2 and CH4 exchange, demonstrating that variation in regional gas exchange is best explained when the effect of grazing, determined by the difference between grazed and ungrazed communities, is included. Further, we identified an interaction between temperature and vegetation community, indicating that grazed regions could experience the greatest increases in CH4 emissions with warming. These results suggest that future GHG fluxes could be influenced by both climate and by changes in herbivore population dynamics that expand or contract the vegetation community most responsive to future temperature change.

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Direct effects of warming increase woody plant abundance in a subarctic wetland

Carlson

Beard

Adler

2018

Ecology and Evolution

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Both the direct effects of warming on a species’ vital rates and indirect effects of warming caused by interactions with neighboring species can influence plant populations. Furthermore, herbivory mediates the effects of warming on plant community composition in many systems. Thus, determining the importance of direct and indirect effects of warming, while considering the role of herbivory, can help predict long‐term plant community dynamics. We conducted a field experiment in the coastal wetlands of western Alaska to investigate how warming and herbivory influence the interactions and abundances of two common plant species, a sedge, Carex ramenskii, and a dwarf shrub, Salix ovalifolia. We used results from the experiment to model the equilibrium abundances of the species under different warming and grazing scenarios and to determine the contribution of direct and indirect effects to predict population changes. Consistent with the current composition of the landscape, model predictions suggest that Carex is more abundant than Salix under ambient temperatures with grazing (53% and 27% cover, respectively). However, with warming and grazing, Salix becomes more abundant than Carex (57% and 41% cover, respectively), reflecting both a negative response of Carex and a positive response of Salix to warming. While grazing reduced the cover of both species, herbivory did not prevent a shift in dominance from sedges to the dwarf shrub. Direct effects of climate change explained about 97% of the total predicted change in species cover, whereas indirect effects explained only 3% of the predicted change. Thus, indirect effects, mediated by interactions between Carex and Salix, were negligible, likely due to use of different niches and weak interspecific interactions. Results suggest that a 2°C increase could cause a shift in dominance from sedges to woody plants on the coast of western Alaska over decadal timescales, and this shift was largely a result of the direct effects of warming. Models predict this shift with or without goose herbivory. Our results are consistent with other studies showing an increase in woody plant abundance in the Arctic and suggest that shifts in plant–plant interactions are not driving this change.

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Vegetation patterns and environmental gradients in coastal meadows on the Yukon–Kuskokwim delta, Alaska

Cited by 57 publications

References 22 publications

Using Videography to Quantify Landscape-Level Availability of Habitat for Grazers: An Example with Emperor Geese in Western Alaska

Using Videography to Quantify Landscape-Level Availability of Habitat for Grazers: An Example with Emperor Geese in Western Alaska

Interactions among vegetation, climate, and herbivory control greenhouse gas fluxes in a subarctic coastal wetland

Direct effects of warming increase woody plant abundance in a subarctic wetland

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