Physiological Characteristics of Southern Appalachian High-Elevation Rock Outcrop Herbs on Clear and Cloudy Days

Horton, Jonathan L.; Culatta, Katherine E.

doi:10.2179/15-081

Cited by 4 publications

(4 citation statements)

References 23 publications

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“…The climate at high elevation is characterized by strong seasonal variation with short, moderately warm, and moist summers, and long, extremely cold, and dry winters [23][24][25][26]. In general, alpine plants adapted to dry conditions can use water very sparingly [27][28][29]. Wind conditions have the greatest influence on physiological change and damage of plants at the treeline, and rocks can provide shelter to tree seedlings from wind during the germination and early growth stages [30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Dynamics of Abies nephrolepis Seedlings in Relation to Environmental Factors in Seorak Mountain, South Korea

Kim¹,

Lim

Yun

2019

Forests

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We present novel evidence of environmental drivers of seedling density in Abies nephrolepis, an alpine and subalpine tree species. Continuous monitoring of natural conditions is required to understand forest ecosystem dynamics. We investigated Abies nephrolepis seedling dynamics in relation to biotic and abiotic factors. The survey, which included the measurement of trees and seedlings, was carried out from March to October in 2016 and 2018. Monitoring sites in the coniferous forests of Seorak Mountain were divided into 27 quadrats. We analyzed relationships using simple and multiple linear regression. The majority of Abies nephrolepis individuals had a diameter at breast height less than l0 cm, and the number of seedlings increased over the study period. This reflects survival and growth due to successive annual mast seeding events. Aspect direction (R2 = 0.201, p < 0.05), rock exposure (R2 = 0.364, p < 0.001), canopy openness (R2 = 0.322, p < 0.05), herbaceous cover (R2 = 0.268, p < 0.01), and basal area (R2 = 0.199, p < 0.05) show significant linear relationships with seedling density. Seedling density was positively related to rock exposure, canopy openness, and species richness, and there was a negative relationship between herbaceous cover and basal area (p < 0.0001). The relative importance of predictor variables was as follows: Rock exposure (40.3%), canopy openness (30.2%), basal area (13.9%), herbaceous cover (11.5%), and species richness (4.1%). Seedling density was most strongly influenced by the presence of large rocks, which provide shelter from harsh winds and a substrate for moss. We conclude that appropriate canopy openness creates a synergistic relationship. We found a positive association between the Abies nephrolepis seedling density in subalpine forests and certain physical environmental factors. Therefore, environmental gradients about the roles of rocks and canopies apply, even in this habitat.

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Section: Introductionmentioning

confidence: 99%

Dynamics of Abies nephrolepis Seedlings in Relation to Environmental Factors in Seorak Mountain, South Korea

Kim¹,

Lim

Yun

2019

Forests

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“…S. tridentata is distributed in a variety of habitats and elevations across its range, including exposed mountaintop habitats in the northeastern US, rocky coastal headlands on the Maine shoreline, high-elevation rock outcrops and exposed rocky balds in the southern Appalachians, and outcrops and high-elevation plateaus in West Virginia (Bresowar & Walker 2011). Many of these habitat types are characterized by shallow soils that do not retain water well, minimal canopy cover, high sun exposure, and a relatively short growing season (Horton & Culatta 2016). S. tridentata can grow on a variety of soil and rock substrates but is thought to be a calcifuge (Wiser 1998).…”

Section: Three-toothed Cinquefoilmentioning

confidence: 99%

“…In Acadia National Park, S. tridentata spring leaf-out was shown to be earlier in warmer microclimates (MacKenzie et al 2018), indicating a future phenological response to climate change. In general, plant species in rock outcrop communities may be particularly impacted by reduced water availability in the future, given the higher cloud ceiling, reduced cloud immersion and greater evaporative demands that are expected to accompany climate change in many regions (Horton & Culatta 2016).…”

Section: Three-toothed Cinquefoilmentioning

confidence: 99%

Second Century Stewardship Refugia Products

Smetzer¹

2019

Climate Change Refugia in the Acadia National Park Region

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“…Epilithic bryophytes generally lack a non-bryophyte substrate (e.g., humus, soil) to hold moisture and are poikilohydric, resulting in potential fluctuations between insufficient and excessive moisture (Glime 2017, Norris 1974, which may make them sensitive to changes in under-canopy climatic conditions. Southern Appalachian spruce-fir forests are immersed in low clouds for a significant proportion of the year Smith 2012, 2013;Horton and Culatta 2016), thereby providing moist conditions for bryophytes in this system (Norris 1974). However, Richardson et al (2003) observed that cloud ceiling height has increased in recent years in the eastern United States, possibly due to climate change.…”

Section: Introductionmentioning

confidence: 99%

Effects of Surveying for the Federally Endangered Spruce-Fir Moss Spider (Microhexura montivaga Crosby & Bishop) on its Bryophyte Habitat

Diggins

Ford

2021

Southeastern Naturalist

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Microhexura montivaga (Spruce-fir Moss Spider) is a federally endangered arachnid endemic to high-elevation montane conifer forests of the southern Appalachian Mountains. The spider is cryptic and difficult to monitor because this species lives in the interface between the bryophyte mat and the rock surface. Since temporary removal of the bryophyte mat is necessary to monitor the spider, surveyors may negatively impact the spider's habitat during monitoring. To help inform survey protocol for this endangered species, we studied reattachment rates of bryophyte mats to rock surfaces after their removal. In 2017, we surveyed sixty 10 cm x 10 cm plots, assigning a plot to either control or treatment (i.e., application of water post-reattachment). We monitored plots for 1 year post-survey to determine reattachment rates. The majority of plots (70%) reestablished after 1 year, whereas 15% did not reattach or showed substantial prolonged (e.g., ~1 year) desiccation and 15% completely fell off or had 100% prolonged desiccation and were chlorotic. We found that mat depth and overstory canopy cover had no effect on mat reestablishment, although bryophyte type did. We found no difference between treatment and control plots, suggesting that no treatment is needed for mats to reestablish under the conditions described. Rock slope significantly influenced reestablishment rates, highlighting that surveying bryophyte mats on slopes >80% may diminish or destroy habitat. Further research is needed to determine long-term monitoring effects on the spider and its habitat, especially in relation to disturbance regimes and ecological restoration of Picea rubens (Red Spruce).

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Physiological Characteristics of Southern Appalachian High-Elevation Rock Outcrop Herbs on Clear and Cloudy Days

Cited by 4 publications

References 23 publications

Dynamics of Abies nephrolepis Seedlings in Relation to Environmental Factors in Seorak Mountain, South Korea

Dynamics of Abies nephrolepis Seedlings in Relation to Environmental Factors in Seorak Mountain, South Korea

Second Century Stewardship Refugia Products

Effects of Surveying for the Federally Endangered Spruce-Fir Moss Spider (Microhexura montivaga Crosby & Bishop) on its Bryophyte Habitat

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