•Start of season (SOS) shows different responses to daytime and nighttime warming.•Such responses also display geographical variations from cold to warm regions.•A new phenology framework considering ...such responses has been proposed.
Spring phenology (i.e., start of season, SOS) of plants in temperate regions has shifted earlier in response to increasing temperature. However, the respective influences of daytime and nighttime warming on the changes in SOS remain poorly understood although an ongoing asymmetric diurnal warming has been observed. In this study, we characterized the responses of satellite-derived SOS to daily minimum temperature (Tmin) and maximum temperature (Tmax) across Appalachian Trail regions in the Eastern United States between 2001 and 2013 using a partial correlation analysis. We found that the partial correlation coefficients between SOS and Tmin(RSOS−Tmin) are opposite in sign compared to that between SOS and Tmax(RSOS−Tmax) in 81.5% of study area. Furthermore, we found a significant decrease in RSOS−Tmin and an increase in RSOS−Tmax from cold to warm regions (P < 0.001). These results suggest that daytime and nighttime warmings play distinct or even contrasting roles in spring phenological changes, which should be considered in phenology models. Thus, we proposed a new framework utilizing both Tmin and Tmax, instead of daily average temperature (Tavg), in modeling phenology, and tested this framework using modified CMIP temperatures projections by 2100 with the consideration of changes in diurnal temperature range. The SOS advancement was less pronounced in TmaxTmin–based projection using this new framework at the mild and warm zones, compared to original Tavg –based projection, and such discrepancy between these two projections increased with time. This study disentangled phenological responses to daytime warming from nighttime warming across a wide range of temperature conditions. Our findings suggest that phenology models should incorporate such divergent phenology responses to improve future phenology projection in light of asymmetric diurnal warming, for an improved representation of land–atmosphere interactions in Earth system models.
Recent research has examined the long-distance hiking community on the Appalachian Trail (AT) and attempted to understand members of this leisure subculture in terms of their sociality and social ...practices. Using Gelder's subcultural perspective, we continue this line of research by comparing hikers' interactions and experiences on the AT to a second well-known long-distance hiking trail, the Pacific Crest Trail (PCT). Analysis of ethnographic field notes and interviews with 72 long-distance hikers suggests that while there are unique experiences associated with each trail, there is a more general long-distance hiking subculture. More specifically, the long-distance hiking subcultures on the AT and PCT are nested or geographically situated subcultures within a larger hiking subculture. This article contributes to scholarship on place attachment, place identity, and leisure subcultures by further examining the long-distance hiking community as well as the role of specific recreational settings in the formation of leisure subcultures and subcultural identities.
•Regression modeling of soil loss on the AT identified seven significant factors.•Incorporation of GIS and LiDAR-derived variables increased explained variation.•Precipitation, landform slope, trail ...grade, and soil substrates were most influential.•Soil loss can be minimized by designing side-hill trails with lower grades.
Recreational activities can negatively affect protected area landscapes and resources and soil erosion is frequently cited as the most significant long-term impact to recreational trails. This study applied extensive multiple regression modeling of trail soil loss to identify influential factors that managers can manipulate to improve the sustainability of trail design and management. Field measurements assessed soil loss as the mean vertical depth along 135 trail transects across the Appalachian Trail sampled along three 5 km trail segments in New Hampshire’s White Mountains National Forest, chosen due to its exceptionally high use and impact. GIS and LiDAR data were used to create many new variables reflecting terrain characteristics that were expected to influence trail erosion and improve predictive models of trail system soil loss. A variety of terrain and hydrology characteristics were applied to model trail soil loss at three spatial scales: transect, trail corridor, and watershed. The model for each spatial scale and a combined model are presented. The adjusted R2 explaining variation in soil loss is 0.57 using variables from all spatial scales, improving on predictive modeling from earlier studies. Environmental and trail design factors such as slope and watershed flow length were found to be significantly correlated to soil loss and have implications for improved sustainable trail design and management.
Tangled Roots Middlefehldt, Sarah; Cronon, William
12/2013
eBook
The Appalachian Trail, a thin ribbon of wilderness running through the densely populated eastern United States, offers a refuge from modern society and a place apart from human ideas and ...institutions. But as environmental historian and thru-hiker Sarah Mittlefehldt argues, the trail is also a conduit for community engagement and a model for public-private cooperation and environmental stewardship.
In Tangled Roots, Mittlefehldt tells the story of the trail s creation. The project was one of the first in which the National Park Service attempted to create public wilderness space within heavily populated, privately owned lands. Originally a regional grassroots endeavor, under federal leadership the trail project retained unprecedented levels of community involvement. As citizen volunteers came together and entered into conversation with the National Parks Service, boundaries between local and nonlocal, public and private, amateur and expert frequently broke down. Today, as Mittlefehldt tells us, the Appalachian Trail remains an unusual hybrid of public and private efforts and an inspiring success story of environmental protection.
Watch the trailer: http://www.youtube.com/watch?v=AFyhuGqbCGc
The wildland-urban interface (WUI) represents landscapes where human settlements coexist with natural features. Trails within the WUI areas, valued for their ecological, recreational, and educational ...values, lack comprehensive research on landscape sensitivity influenced by both landscape and urban development. This paper addresses the gap by proposing a comprehensive landscape sensitivity index (CLSI) using multiple regression, cluster analysis, and correlation analysis. The Appalachian Trail (AT) serves as a case study to explore the characteristics of high sensitivity areas, considering various attributes and their connection with federal reserved land. Results show that eliminating covariance in landscape indices refines the landscape aggregation pattern, with Moran's I decreasing from 0.776 to 0.449, aligning with the observed fragmented landscape. In comparison to modified landscape indices (MLSI), the CLSI reveals that 85.6% of the area experiences changes in landscape sensitivity, with 42.5% of the AT region displaying significant landscape sensitivity, including 4.9% as having high landscape sensitivity (HLS), influenced by rock formations, wetlands, and biodiversity. A spatial mismatch is identified between HLS and current federal preservation efforts, with a correlation of only 0.011. The paper proposes tailored conservation strategies for HLS areas in urban, wilderness, and protected regions. Considering the combined impact of ecological and urbanization forces, this study assists in prioritizing land conservation objectives and finding a balance between wilderness protection and urban development.
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•The comprehensive landscape sensitivity index is applicable in the WUI region.•Rock, wetlands, and biodiversity are the key factors of high landscape sensitivity.•Only 14.3% of the landscape sensitivity is agreed considering urban disturbances.•Elimination of co-linear landscape indices reveals fragmented landscape pattern.•Spatial mismatch exists between federal land and high landscape sensitivity areas.
•Techniques quantified relationships between trail conditions and hiking experiences.•Hiking experiences can change based on trail conditions.•Mapping trail conditions and hiking experiences is ...important for sustainability.•Managers can use results to design trails for specific hiking experiences.
Trail users that experience acceptable social and ecological conditions are more likely to act as trail stewards, exhibit proper trail etiquette, and use low-impact practices. However, the relationships between specific trail conditions and experiential elements of long-distance hiking are not well understood. Therefore, the purpose of this study was to identify how trail conditions influence particular elements of the long-distance hiking experience. The researchers used a mixed-methods approach involving semi-structured interviews (n = 17), quantitative questionnaires (n = 336), ecological measurements of trail conditions (n = 21–5 km sections), and modified Recreation Suitability Mapping (RSM) techniques to quantify the relationships between five trail conditions (trail incision, muddiness, rugosity, trail width, and gradient) and four experiential elements of long-distance hiking (level of challenge, perceived impact to musculoskeletal system, valuation of tread aesthetics, and ability to maintain an ideal hiking pace). Quantified values were weighted, analyzed, and mapped using SPSS 22.0 and ArcMap 10.2.2. Significant differences exist in the scores and distributions of ecological measures across all sections, indicating that trail conditions vary significantly across sampled trail sections. Although, long-distance hikers felt all four experiential elements were important, tread aesthetics was ranked by 50.2% of sampled hikers as the most important experiential element to the overall experience. The resulting information after applying the weights suggests what particular type of experience is likely for each trail section considering the presence of trail conditions.
Acidic atmospheric deposition has adversely affected aquatic ecosystems globally. As emissions and deposition of sulfur (S) and nitrogen (N) have declined in recent decades across North America and ...Europe, ecosystem recovery is evident in many surface waters. However, persistent chronic and episodic acidification remain important concerns in vulnerable regions. We evaluated acidification in 269 headwater streams during 2010–2012 along the Appalachian Trail (AT) that transits several ecoregions and is located downwind of high levels of S and N emission sources. Discharge was estimated by matching sampled streams to those of a nearby gaged stream and assuming equivalent daily mean flow percentiles. Charge balance acid‐neutralizing capacity (ANC) values were adjusted to the 15th (Q15) and 85th flow percentiles (Q85) by applying the ANC/discharge slope among sample pairs collected at each stream. A site‐based approach was applied to streams sampled twice or more and a second regression‐based approach to streams sampled once to estimate episodic acidification magnitudes as the ANC difference from Q15 to Q85. Streams with ANC <0 μeq/L doubled from 16% to 32% as discharge increased from Q15 to Q85 according to the site‐based approach. The proportion of streams with ANC <0 μeq/L at low flow and high flow decreased from north to south. Base cation dilution explained the greatest amount of episodic acidification among streams and variation in sulfate (SO42−) concentrations was a secondary explanatory variable. Episodic SO42− patterns varied geographically with dilution dominant in northern streams underlain by soils developed in glacial sediment and increased concentrations dominant in southern streams with older, highly weathered soils. Episodic acidification increased as low‐flow ANC increased, exceeding 90 μeq/L in 25% of streams. Episodic increases in ANC were the dominant pattern in streams with low‐flow ANC values <30 μeq/L. Chronic and episodic acidification remain an ecological concern among AT streams. The approach developed here could be applied to estimate the magnitude and extent of chronic and episodic acidification in other regions recovering from decreasing levels of atmospheric S and N deposition.
Despite recent declines in acidic atmospheric deposition across North America, stream acidification remains a concern. Chronic and episodic acidification were evaluated in 269 headwater streams along the Appalachian Trail in the eastern United States. Acidic streams doubled to about one third of all streams from low flow to high flow. Base cation dilution was the major episodic acidification driver, but changes in sulfate concentrations were an important secondary driver with dilution dominant in the north and increased concentrations dominant in the south.
Cultural geographers working with non-representational theories have recently returned to thinking about representations as actors in the relational processes of making spaces, selfhood and ...communities. A particular focus for studies of literary texts is examining how representation 'takes place', how texts are part of what happens in the world, and how we can better understand the force of representations-in-relation at work. In this paper I will address this question, by examining the role that representations play as actors in the production of community and selfhood among hikers on the Appalachian Trail. As hiker representations straddle digital and non-digital media in the twenty-first century, scholarly approaches continue to view them as little more than mediators, or ersatz forms of, in-person speech. Here, I take a non-representational approach to hiker writings to focus on the relationships that develop between AT hikers and the writings they encounter as a means of understanding how these representations-in-relation take place on the trail, and how they contribute to what happens - that is, to the production of community and subjectivity among Appalachian Trail hikers.
Abstract
The Appalachian Trail is a 2,000-mile-long wilderness trail shared by hikers and numerous nonhuman animal species, including the American Black Bear (Ursus americanus). In many areas of the ...trail, bears have become habituated to humans, occasionally leading to conflict between them. Some hikers choose to blog about their experiences on the trail, including their experience of living among bears. Their narratives center around space-oriented themes of proximity, dwelling, and segregation. The concept of dwelling is useful in understanding how hikers and bears come to share a lifeworld in which each species is usually given enough room to dwell in their own way. A hiker's immersion in the spaces belonging to bears can lead them to a more nuanced appreciation of bears as autonomous beings. Dwelling also points towards a way of being with nonhuman animals that avoids doing harm to them or to their homes.
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