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Environmental noise knows no boundaries, affecting even protected areas. Noise pollution, originating from both external and internal sources, imposes costs on these areas. It is associated with adverse health effects, while natural sounds contribute to cognitive and emotional improvements as ecosystem services. When it comes to parks, individual visitors hold unique perceptions of soundscapes, which can be shaped by various factors such as their motivations for visiting, personal norms, attitudes towards specific sounds, and expectations. In this study, we utilized linear models and geospatial data to evaluate how visitors’ personal norms and attitudes, the park’s acoustic environment, visitor counts, and the acoustic environment of visitors’ neighborhoods influenced their perception of soundscapes at Muir Woods National Monument. Our findings indicate that visitors’ subjective experiences had a greater impact on their perception of the park’s soundscape compared to purely acoustic factors like sound level of the park itself. Specifically, we found that motivations to hear natural sounds, interference caused by noise, sensitivity to noise, and the sound levels of visitors’ home neighborhoods influenced visitors’ perception of the park’s soundscape. Understanding how personal factors shape visitors’ soundscape perception can assist urban and non-urban park planners in effectively managing visitor experiences and expectations.

Experiments with controlled levels of recreational camping were conducted on previously undisturbed sites in two different plant communities in the subalpine zone of the Wind River Mountains, Wyoming, USA. The plant communities were coniferous forest with understory dominated by the low shrub Vaccinium scoparium and a riparian meadow of intermixed grasses and forbs, of which Deschampsia cespitosa was most abundant. Sites were camped on at intensities of either one or four nights per year, for either one (acute disturbance) or three consecutive years (chronic disturbance). Recovery was followed for three years on sites camped on for one year and for one year on sites camped on for three years. Reductions in vegetation cover and vegetation height were much more pronounced on sites in the forest than on sites in the meadow. In both plant communities, increases in vegetation impact were not proportional to increases in either years of camping or nights per year of camping. Close to the center of campsites, near-maximum levels of impact occurred after the first year of camping on forested sites and after the second year on meadow sites. Meadow sites recovered completely within a year, at the camping intensities employed in the experiments. Forest sites, even those camped on for just one night, did not recover completely within three years. Differences between acute and chronic disturbance were not pronounced.

Trampling experiments were conducted in five high-elevation plant communities in the Wind River Mountains. In one experiment (simulating infrequent acute disturbance), plots were trampled once and recovery was followed for 3 yr. In another experiment (simulating chronic disturbance), plots were trampled for three successive years and recovery was followed for one year. Yearly trampling intensities were 0 to 500 passes (up to 800 and 1000 in two communities). Structural responses (reductions in cover and height) were more pronounced than compositional responses. Low levels of trampling caused substantial reductions in cover and height, but rates of change decreased as trampling intensity increased. The ability of different plant communities to tolerate trampling disturbance varied by at least an order of magnitude, suggesting that impacts can be reduced by directing use to more tolerant plant communities. Moreover, tolerance can be gauged on the basis of readily observable plant characteristics. Plant communities with groundcover dominated by chamaephytes (primarily low, woody shrubs) or by erect, caulescent forbs were less resistant than those with groundcovers dominated by turf-forming or caespitose graminoids, or by forbs with matted, caespitose or rosette growth forms. Plant communities with woody, chamaephytic groundcover were less resilient than other plant communities.

Large intact soil cores of nearly pure stands of Pascopyrum smithii (western wheatgrass, C₃) and Bouteloua gracilis (blue grama, C₄) were extracted from the Central Plains Experimental Range in northeastern Colorado, USA and transferred to controlled environment chambers. Cores were exposed to a variety of water, temperature and CO₂ regimes for a total of four annual growth cycles. Root subsamples were harvested after the completion of the second and fourth growth cycles at a time corresponding to late winter, and were examined microscopically for the presence of mycorrhizae. After two growth cycles in the growth chambers, 54% of the root length was colonized in P. smithii, compared to 35% in blue grama. Field control plants had significantly lower colonization. Elevation of CO₂ increased mycorrhizal colonization in B. gracilis by 46% but had no effect in P. smithii. Temperatures 4°C higher than normal decreased colonization in P. smithii by 15%. Increased annual precipitation decreased colonization in both species. Simulated climate change conditions of elevated CO₂, elevated temperature and lowered precipitation decreased colonization in P. smithii but had less effect on B. gracilis. After four growth cycles in P. smithii, trends of treatments remained similar, but overall colonization rate decreased.

In many back-country areas of the US, where recreational use is increasing dramatically, the disposal of human waste is a problem that has received little attention. However, the transmission of disease-causing pathogens from human feces is a serious health problem. The significance of the problem is considered in terms of Giardia sp., Cryptosporidium, Salmonella sp., Campylobacter jejuni, and Yersinia enterocolitica. A review is presented of the fate and health impacts of pathogens in soil and in water. Recommendations for human-waste disposal under these conditions are proposed, based on a philosophy of minimum impact.

The rate of acetylene reduction was measured as a function of time after addition of 10% acetylene in Alnus, Casuarina, Ceanothus, Datisca, and Myrica. The maximum rate occurred after 45 to 60 seconds and was maintained for an additional 0.5 to 4 minutes before a decline in rate to 30 to 90% of the maximum. The rate then recovered to a value of 63 to 98% of the maximum. Removal of the shoot and lower roots did not affect nodule activity.

/ Proper disposal of human waste is an important concern for the appropriate management of wildlands. This paper reviews the state of knowledge regarding pathogens and human waste disposal in dispersed backcountry recreation areas in the United States. Of concern is the impact of travelers, such as backpackers, backcountry skiers, and mountaineers, in areas where toilets are not provided. At this time, the magnitude of problems related to human waste disposal in wildlands is unclear. Aesthetics and water contamination with the resultant potential for disease transmission are the predominant issues. Few studies have analyzed the aesthetics of human waste disposal. In wildlands, contamination of water sources primarily originates from surface soil. The fate of enteric pathogens on or in soils is highly variable and dependent on the complex interactions of many factors, most importantly soil type, moisture, and temperature. It is difficult to make general recommendations that apply to all ecosystems. There is still a relative dearth of studies that allow the manager or visitor to come up with specific practices that are the best for their area. The preferred method of disposal remains to dig a small hole (cat hole) and bury the waste. Other site specific methods are also discussed. Treatment of drinking water has become standard practice for most backcountry travel. With such treatment, there is little evidence currently to suggest that the health hazard to humans is great enough to impose further regulation in areas currently using cat holes.

Recent years have witnessed considerable advances in information retrieval for European languages other than English. We give an overview of commonly used techniques and we analyze them with respect to their impact on retrieval effectiveness. The techniques considered range from linguistically motivated techniques, such as morphological normalization and compound splitting, to knowledge-free approaches, such as n-gram indexing. Evaluations are carried out against data from the CLEF campaign, covering eight European languages. Our results show that for many of these languages a modicum of linguistic techniques may lead to improvements in retrieval effectiveness, as can the use of language independent techniques.