The impacts of trail infrastructure on vegetation and soils: Current literature and future directions

Tourist Trampling on a Peripheral Plant Population Restricted to an Urban Natural Area in the Capo Sant'Elia Promontory (Sardinia, W-Mediterranean Basin)

Urban natural areas provide important ecological services such as biodiversity conservation, as well as opportunities for people to connect with nature and preserve cultural heritage. However, the increasing demand for access to natural areas and the expansion of human recreational activities, such as hiking and biking, pose threats to these ecosystems, especially for animal and plant species, finally resulting in biodiversity loss. This study explores the intricate link between human trampling, plant density, and the morphological and reproductive characteristics of Globularia alypum L., a plant with a peripheral population in Sardinia restricted to a natural area within an urban context. The study examined trampling effects on 75 plots along a frequently used path crossing the plant's core population. Similar environmental conditions were assumed, with differences attributed to human trampling intensity and plant density, and morphological and reproductive traits were measured within each plot. Our results showed that human trampling caused differences in the morphological traits of plants, whereas, in contrast, reproductive traits are less vulnerable to human trampling than morphological ones. As a result, trampled areas may experience decreased plant recruitment, which can have long-term implications for plant population dynamics. Understanding the relationship between trampling effects and the sensitivity of peripheral plant populations is crucial for effective conservation and management strategies.

Vegetation type and trail use interact to affect the magnitude and extent of recreational trail impacts on plant communities

Protected areas may prohibit large-scale deforestation and development, but still allow recreation via networks of roads and trails. Managers need to understand how the type of trail usage and the habitat the trail traverses influence the nature and extent of the trail impact. We measured the effect of trails on plant communities in a large, protected area in the southern Rocky Mountains of Alberta, Canada. We surveyed 118 transects adjacent to trails and 24 control transects at least 100 m from trails, recording the presence and abundance of all vascular plant species. We modelled changes in species richness, community composition, and the presence of exotic species as a function of trail type, vegetation type, and the distance from the trail edge. Overall, species richness increased with proximity to trails and community composition shifted significantly, with a greater likelihood of exotic species presence closer to trails. Heightened species richness and greater probability of exotic species presence extended a greater distance from off-highway vehicle trails than from footpaths, but only in shrubland and mixed forest vegetation. In addition, exotic species at higher elevations were most often associated with off-highway vehicle trails. Our study shows that the magnitude and extent of trail impacts on plant communities varies depending on trail type, vegetation type, and sometimes interactions between the two. The high frequency and intensity of off-highway vehicle trail use likely increases both propagule pressure and the severity of disturbance, while vegetation type determines light availability and hence invasibility. Managers can use this information to prioritize trail areas for exotic species monitoring and restrict high-intensity off-highway vehicle trails to less sensitive vegetation types at lower elevations.

Road Impact on Plant Colonization in the Arid Timanfaya National Park

Roads have the potential to alter local environmental conditions, such as the availability of water and nutrients, and rapidly create suitable habitats for the establishment of both native and non-native plant species, transforming the ecosystems. This is a challenge in Timanfaya National Park and Los Volcanes Natural Park on Lanzarote Island, protected areas that have experienced primary succession after recent volcanic eruptions. In arid ecosystems, changes in abiotic conditions along roadsides might facilitate colonization and plant growth. We analyzed the effect of roads and road type on plant species composition and richness at a spatiotemporal scale. Vascular plant species were systematically recorded at three distances from the road edge on both sides, across fourteen zones in the wet and dry seasons, for three years. Results showed that there were slight differences on species composition depending on the distance to the road edge, as well as on the zones. Species richness was also determined by the interaction of the position, zones, and season, being higher at the road edge. Furthermore, zones with higher traffic intensity showed a higher presence of both native and non-native species. This study highlights the importance of the awareness about the road impacts on species composition by enhancing the colonization capacity of species while facilitating the entry of invasive ones. Good management practices regarding infrastructures in natural protected areas are crucial for the conservation of their unique flora, landscapes, and natural succession processes.

Not all who wander are lost: Trail bias in community science

The exponential growth and interest in community science programs is producing staggering amounts of biodiversity data across broad temporal and spatial scales. Large community science datasets such as iNaturalist and eBird are allowing ecologists and conservation biologists to answer novel questions that were not possible before. However, the opportunistic nature of many of these enormous datasets leads to biases. Spatial bias is a common problem, where observations are biased towards points of access like roads and trails. iNaturalist-a popular biodiversity community science platform-exhibits strong spatial biases, but it is unclear how these biases affect the quality of biodiversity data collected. Thus, we tested whether fine-scale spatial bias due to sampling from trails affects taxonomic richness estimates. We compared timed transects with experienced iNaturalist observers on and off trails in British Columbia, Canada. Using generalized linear mixed models, we found higher overall taxonomic richness on trails than off trails. In addition, we found more exotic as well as native taxa on trails than off trails. There was no difference between on and off trail observations for species that are rarely observed. Thus, fine-scale spatial bias from trails does not reduce the quality of biodiversity measurements, a promising result for those interested in using iNaturalist data for research and conservation management.

Trail sustainability: A state-of-knowledge review of trail impacts, influential factors, sustainability ratings, and planning and management guidance

Protected areas (PAs) provide many important recreational, social, and economic benefits that are largely dependent on their ability to sustain visitation. Trail networks are a critical tourism infrastructure element that directly accommodate high quality recreation activities and experiences while providing access to and protection of irreplaceable natural and cultural resources. Unfortunately, most trail networks consist of historic "legacy" trails that were not sustainably designed and whose intensive use cause unacceptable impacts to PA resources, experiences, and values. This paper provides an international state-of-knowledge review of trail science research within the field of recreation ecology to describe common trail impacts and factors that influence trail degradation that trail stewards can manipulate to enhance the sustainability of trail networks. Two emerging models that seek to rate trail topographic sustainability are presented to illustrate their potential utility to PA managers. Expanding and incorporating trail science research into the sustainable trail planning, design, and Best Management Practice literature are also discussed.

Trail running events contribute microplastic pollution to conservation and wilderness areas

Clothing and footwear designed for trail running shed microplastics (MPs) during use. Trail running events may therefore present a significant source of MP pollution in conservation and wilderness areas. Microplastics may present long-term risks to biodiversity and endemic plant and animal species in such areas. In this study, we used a before-after-control-impact approach to quantify and characterise MP emissions from clothing and shoe outsoles during trail running events. Microplastic deposition on trail surfaces was assessed using both a controlled study and during two public trail running events in New South Wales, Australia (the Duval Dam Buster and the Washpool World Heritage Trail Race). Microplastics were present on trails after all events and included fibres and rubber fragments. Microplastic counts varied considerably depending on trail surface hardness and gradient, and clothing and footwear properties. The controlled study showed running tights (leggings) and shoes with soft rubber outsoles produced more MPs than shirts and hard rubbers. In the trail running events, abrasive wear to shoe outsoles produced an average of 0.3 ± 0.1 to 0.9 ± 0.2 MPs/linear metre/runner, and clothing produced 0.7 ± 0.3 to 2.0 ± 0.3 fibres/linear metre/runner, with fibres accounting for 63-69% of MPs. Microplastic deposition from both footwear and clothing was higher on sloped and rock trail surfaces than flat and soil surfaces. Laser Direct Infrared (LDIR) Imaging indicated the main types of MPs present on trails were polyurethane, polyethylene terephthalate and polyamide. Trail running is increasing in popularity and large-scale events may cause a rapid and significant input of MPs in protected areas. Land managers, event coordinators and outdoor apparel manufacturers could mitigate MP impacts however, by diverting foot traffic around ecologically sensitive areas, capping participant numbers, and developing abrasion resistant clothing and footwear.

Distribución de plantas nativas y exóticas a lo largo de gradientes de elevación en senderos de montaña en los Andes de Mendoza, Argentina

Introducción y objetivos: El cambio climático, el ganado y el creciente uso turístico favorecen la dispersión de plantas exóticas, amenazando la conservación de los ecosistemas altoandinos. Estudiamos los patrones de distribución de plantas nativas y exóticas en senderos recreativos de montaña. M&M: Implementamos el protocolo MIREN en seis senderos (2400-3600 m s.n.m.) en dos áreas protegidas de los Andes centrales de Mendoza en las Cordilleras Frontal y Principal. Resultados: Encontramos 180 especies nativas y 41 exóticas. La riqueza de especies nativas fue máxima a elevaciones intermedias, mientras que la riqueza de exóticas disminuyó con la elevación. La riqueza regional de nativas fue mayor en la Cordillera Frontal que en la Principal (114 versus 71 nativas, respectivamente) mientras que la riqueza regional de exóticas fue menor en la Frontal que en la Principal (20 versus 28 exóticas, respectivamente). La riqueza de exóticas por parcela fue mayor en la Cordillera Frontal que en la Principal. El rango de distribución altitudinal de exóticas fue mayor en la Cordillera Frontal. Dos exóticas abundantes, Taraxacum officinale y Cerastium arvense, estuvieron a lo largo de todo el gradiente en la Cordillera Frontal, alcanzando los 3600 m s.n.m. Encontramos siete exóticas no citadas anteriormente. Conclusiones: Los nuevos registros amplían los rangos de distribución conocidos para algunas especies exóticas. A pesar de que el número de especies exóticas fue similar cerca y lejos de los senderos, cinco especies sólo estuvieron en los bordes de los mismos, lo que sugiere que los senderos favorecen los procesos de invasión.

A comparative analysis of the past and present occurrences of some species of Paphiopedilum (Orchidaceae) in northeastern India using MaxEnt and GeoCAT

Members of the genus Paphiopedilum are well known for their long-lasting unique flowers. They are becoming rare due to over-collection and habitat loss because of human disturbances and deforestation. The present study aimed to compare the past and present occurrences of the genus Paphiopedilum in northeastern India using MaxEnt and GeoCAT. A historical occurrence model (HOM) was prepared using secondary data, and an actual occurrence model (AOM) was constructed with primary field data. The HOM and AOM revealed that bioclimatic factors, topography and precipitation play a significant role in the survival of Paphiopedilum populations in northeastern India in both the current and historical distributions. The other vital environmental variables were elevation (h_dem), mean diurnal range (bio_2), annual mean temperature (bio_1), temperature annual range (bio_5) and annual precipitation (bio_12). The results showed a sharp decline in the extent of occurrence and the area of occupancy of Paphiopedilum in the study area. The extent of occurrence and area of occupancy for HOM were 170,972 km2 and 18 km2. For the AOM, they were 125,315 km2 and 12 km2, respectively. The HOM model indicated that Paphiopedilum was earlier growing sporadically. On the other hand, the AOM result indicates that it is presently growing sparsely in isolated pockets that are more prone to extinction. Paphiopedilum can be conserved successfully using an integrative conservation approach, comprising ecological modeling techniques to search for additional locations, ex situ propagation techniques, and possible reintroduction in selected areas.

Response of Sediment Connectivity to Altered Convergence Processes Induced by Forest Roads in Mountainous Watershed

Forest roads significantly affect sediment connectivity in mountainous catchments by contributing to the production of and disturbing the confluence of sediment-loaded runoff. This study considered forest roads as pathways and sinks of sediment-loaded runoff to understand the effects of forest roads on the confluence characteristics and sediment connectivity in mountainous a catchment using a scenario simulation. In order to determine the contribution and spatial relationship between sediment connectivity and influencing factors, this study utilized buffer analysis, an extremely randomized tree model, and multiscale geographically weighted regression. The results show that the presence of forest roads significantly changes the transport process and connectivity of runoff and sediment in the mountainous catchment. Specifically, flow length increases, but flow accumulation, upslope contributing area, and topographic index decrease with increasing distance from roads and streams. Meanwhile, the effects of roads on convergence characteristics and sediment connectivity are mainly manifested within a certain threshold that varies with different confluence characteristics. Moreover, sediment connectivity increases when considering roads as pathways and sinks of sediment-loaded runoff, especially on the upper hillslopes intercepted by roads and at the road–stream crossings. In addition, the closer the distance to the roads, the greater the impact of road on the confluence characteristics and sediment connectivity. Change in flow length is the most important factor affecting the sediment connectivity among all of the other convergence, terrain, and spatial distance characteristics. The longer the flow length, the lower the sediment connectivity. In conclusion, this study demonstrates that the altered confluence processes by roads increases the possibility that sediment-loaded runoff will be transported to the catchment outlet, which is of significance for the proper management of forest roads in mountainous catchments.

Effects of road and river networks on sediment connectivity in mountainous watersheds

Road and river networks in mountainous watersheds play an important role in transporting eroded sediments. However, the underlying transport mechanisms remain poorly understood, particularly in terms of how alterations to flow paths caused by road and river networks influence sediment connectivity. Therefore, using data from the Dongshuanghe (DSH) watershed in the Dabie Mountain in Central China, this study investigated the spatial relationships between road and river networks, analyzed the effects of road and river networks on the spatial distribution of sediment connectivity, and determined the primary factors influencing sediment connectivity. The primary factors were identified using the index of connectivity (IC), buffer analysis, a random forest (RF) model, and a geographical detector model (GDM). The results indicated that road and river networks were spatially closely associated: closer to rivers, the density of high-grade roads increased, while farther from road-river crossings, the length and density of rivers and high-grade roads decreased. Both road and river networks affected the IC. In particular, for permanent drainage lines or local sinks, the average value of IC_R (i.e., IC affected by road networks, -0.97) was higher than that of IC (-2.17). Thus, values of IC_R decreased substantially with increasing distance to the closest roads (R² = 0.73). However, beyond a threshold of 150 m, the effect of roads on IC_R gradually diminished. In addition, the structural characteristics of road networks, particularly slope (Road_S), had greater explanatory power for spatial variation in the IC_R. In conclusion, compared to the river networks, the effect of road networks on IC_R was more important, which was not only reflected in the spatial distribution of IC_R, but also in the factors influencing IC_R.

The Effect of the Distance from a Path on Abiotic Conditions and Vascular Plant Species in the Undergrowth of Urban Forests and Parks

Urban forests and parks are essential for the maintenance of biodiversity as well as human health and well-being. Residents and tourists commonly use urban forests and parks for recreational and sport purposes, contributing to changes in vegetation. This study aimed to assess the effect of distance from formal paths on the abiotic conditions, vegetation cover, as well as ecological diversity of vascular plant species in the undergrowth of urban forests and parks. The investigations were carried out in 2021 in 10 urban forests and 10 urban parks located in Kraków (southern Poland), using a total of 400 plots (1 × 1 m) situated in close (CL) and further (FU) vicinity of formal paths. We found a positive effect of the distance from the path on the depth of the compact soil layer, vegetation cover and height of the tallest shoot in the undergrowth of urban forests and parks. On the other hand, the distance from the path had a negative effect on the number of vascular plant species in the undergrowth in both forests and parks. Forests and parks differed significantly from each other in light intensity, the content of P in soil, depth of compact soil layer, number of species, as well as in cover-abundance of species representing different life forms, dispersal types, habitat affiliations and origins. Trampling leads to low plant cover and height of the undergrowth, as well as contributing to shallow localization of the compact soil layer near paths. Human movement on paths (walking, running, biking) with accompanying pets contributes to the successful dispersal of plants, resulting in high species richness. High light intensity in urban parks enhances the total number of species, cover-abundance of meadow and grassland plants, as well as cover-abundance of hemicryptophytes. The number of alien species was higher in parks than in forests, but the cover-abundance of alien plants was higher in forests than in parks. Urban forests are more suitable for the growth and biomass production of some alien herbs than urban parks, as mowing commonly used in parks appears to be an important factor in reducing their cover abundance. Regular fertilization and irrigation contribute to the high content of phosphorus in the soil, as well as to the high cover-abundance of meadow and grassland plants in urban parks. Urban forests enhance cover abundance of plants with dispersal mechanisms of the Bidens and Lycopodium types, whereas urban parks promote cover abundance of plants with the dispersal of the Allium type. Further study is needed to confirm the role of urban forests and parks in the preservation of ancient forest species, as well as to develop an appropriate design of paths that will allow the protection of vegetation and soil in urban forests and parks.

Severe vegetation degradation associated with different disturbance types in a poorly managed urban recreation destination in Iran

Recreational activities worldwide have major impacts on the environment. This study examined the impact of different kinds of recreational activities on plant communities in a highly visited park in Mashhad, Iran. Vegetation in the park was sampled along 41 random 10-m transects with different human disturbances (trails, dirt roads, campsites) and undisturbed communities. Life form spectrum, species composition, species and phylogenetic diversity were determined for all communities. Disturbance increased the frequency of therophytes, but decreased the frequency of chamaephytes and percentage vegetated area. Recreational-mediated disturbance had variable impact on species composition, but decreased species and phylogenetic diversity compared with undisturbed areas. Roads and campsites caused the greatest damage, while trails had the smallest negative impact on vegetation. This study showed that damage to (semi-)natural park vegetation differs with recreation activity. This finding can help prioritise management activities to minimise negative impacts of recreation activities on local vegetation. The current visitor load to the urban park studied here appears too high to be sustainable over time, so better monitoring and restrictions on visitor numbers may be needed to minimise the negative impacts on park vegetation. The camping impacts can be managed by creating clusters of designated campsites to spatially concentrate the impact area. Low-impact practices should be communicated to visitors.

Reaching over the gap: A review of trends in and status of red panda research over 193 years (1827-2020)

The red panda is a unique species taxonomically known for its peculiar biological and ecological characteristics, and extreme attractiveness. Despite being highly significant from conservation, scientific and economic perspectives, this species has experienced a declining population in the wild. Thus, to direct further research priorities and conservation actions and assess gaps in the current research trend of this species, a systematic literature review was conducted covering 175 journal articles published in English over 193 years (1827-2020). This review revealed that (1) the biological aspect was highly studied compared to other thematic areas of red panda (2) captive-based studies are relatively higher than the studies based in wild populations (3) China is leading the red panda studies amongst all red panda range (4) The universities were found contributing more to red panda studies than other institutions. Surprisingly, we found that the researchers from the non-range country were leading red panda study than those from range countries. Our review highlighted the need of prioritising studies in underrepresented locations and understudied thematic areas focusing on the assessment of climate change impact, bamboo distribution status, ecosystem services of red panda habitat, behavior and movement ecology, population estimation, and metapopulation dynamics. We urge landscape-level studies and long-term population monitoring. Besides, we also suggest the documentation and evaluation of the effectiveness of ongoing red panda-focused conservation programs. We also stress the need for strengthening the capacity of institutions and people from range countries.

Impact of recreational transformation of soil physical properties on micromolluscs in an urban park

The paper assesses the effect of transformation of soil physical properties on the abundance of micromolluscs in the conditions of an urban park. The studies were carried out in Novooleksandrivskiy Park (Melitopol, Ukraine). An experimental polygon was represented by 7 transects with 18 sampling points in each. The interval between the points in the transect, as well as the interval between transects, was 3 meters. The total area of the polygon was 1,134 m2. The tree species growing within the polygon were Quercus robur, Sophora japonica, and Acer campestre. Shrubs were represented by Ulmus laevis, Tilia cordata, Celtis occidentalis, and Morus nigra. The locations of the trees and shrubs were mapped. The crowns of tree and shrub plants formed a dense canopy and a shady light regime. The grass cover was practically absent. The soil mechanical resistance, soil aggregate-size distribution, electrical conductivity of soil, soil moisture and bulk density were measured. We recorded 618 individuals of Vallonia pulchella, 120 individuals of Cochlicopa lubrica, and 58 individuals of Acanthinula aculeata within the surveyed polygon. We extracted three principal components, which could explain 60.9% of the variation in the feature space of the soil properties. The principal component 1 explained 42.0% of the variation of the feature space and depended on the soil penetration resistance throughout the whole profile, aggregate composition, density, electric conductivity and moisture content of soil. This component reflected a tendency for soil penetration resistance and soil density to increase near recreational trails. The principal component 1 was used to indicate the gradient of recreational transformation of the soil. The principal component 2 was able to explain 10.6% of the variation in the feature space. It negatively correlated with the distance from the recreational trail, soil penetration resistance at the depth of 35 cm or more, soil electrical conductivity, and the proportion of aggregates greater than 3 mm in size. This component positively correlated with soil penetration resistance at 0–5 cm depth and the proportion of aggregates less than 0.5 mm in size. This component can be interpreted as a "halo" from the recreational trail, or a gradient of indirect soil transformations adjacent to the zone of intense recreational load. The principal component 3 was able to explain 8.3% of the variation in the feature space. It positively correlated with soil penetration resistance at the depth of 20–40 cm, the proportion of 0.5–7.0 mm aggregates, and soil moisture. It negatively correlated with the proportion of aggregates larger than 7 mm and smaller than 0.25 mm. This component indicated a variation in soil properties that was induced by causes independent of recreational exposure. The extracted gradients of soil properties significantly influenced the abundance of micromollusc populations. The abundance of all species decreased after increase in recreational load. Micromollusc species responded to direct recreational exposure as plateau (C. lubrica) and asymmetric unimodal responses (V. pulchella and A. aculeata).

A Hybrid Method for Citizen Science Monitoring of Recreational Trampling in Urban Remnants: A Case Study from Perth, Western Australia

Vegetation trampling that arises from off-trail excursions by people walking for recreation can negatively impact the structure of understory plants in natural spaces that are an essential element of urban green infrastructure in a modern city. In addition to reducing the esthetic quality and environmental values of urban remnant and replanted native vegetation, such trampling reduces the habitat that supports wildlife populations within the urban fabric. This case study draws upon several disparate methods for measuring vegetation structure and trampling impacts to produce a hybrid method that community-based citizen scientists (and land managers and other researchers) could use to simply, rapidly, and reproducibly monitor how trampling associated with urban recreation trails impacts the structure of understory vegetation. Applying the novel hybrid method provided evidence that trampling had reduced the vegetation structure adjacent to a recreational walking trail in an urban woodland remnant in Perth, Western Australia. The hybrid method also detected ecological variability at the local ecosystem-scale at a second similar woodland remnant in Perth. The hybrid sampling method utilized in this case study provides an effective, efficient, and reproducible data collection method that can be applied to recreation ecology research into aspects of trampling associated with trail infrastructure.

Differential responses of prairie rodents to edge effects from recreational trails

Edge effects are a common phenomenon in which an ecological variable changes with respect to distance from a habitat edge. Recreational trails may constitute a habitat edge for prairie rodents because of high human presence, high predator presence, or limited shelter compared to the prairie core. Despite the prevalence of trails in conservation parcels, their effect on wildlife distribution remains largely unstudied. We examined the impacts of recreational trails on small mammal activity in the restored prairies of the Cowling Arboretum at Carleton College. The prairies were restored from 1995 to 2008 and now comprise a contiguous prairie block of approximately 155 ha. Over 2 consecutive summers, we used infrared motion-sensing cameras to record the relative amount of time rodents spend at baited stations placed at different distances from the trail. The results varied between taxa: voles (Microtus spp.) avoided trail edges whereas mouse (Cricetidae and Dipodidae) and thirteen-lined ground squirrel (Ictidomys tridecemlineatus) activity was unaffected by trail proximity. Trails may therefore have species-specific effects on small mammals, with potential consequences for the connectivity and distribution of populations.

Going off trails: How dispersed visitor use affects alpine vegetation

Mountain protected areas provide a range of ecosystem services including conserving biodiversity, while often providing recreation and tourism opportunities. Unfortunately, tourists and pack animals used to transport equipment can damage sensitive alpine vegetation particularly when they leave trails. This study assessed the impacts of disturbance from off trail use on alpine vegetation in a popular park in the Andes. The effect of different levels of disturbance as well as abiotic factors on alpine steppe vegetation was assessed using generalized linear models and ordinations in 91 plots (20 m²) in the popular Horcones Valley that is used to access remote areas in Aconcagua Provincial Park in Argentina. Disturbance off trails resulted in declines in the cover of native plants, including the endemic shrub Adesmia aegiceras but increases in the cover of herbs including the non-native Convolvulus arvensis. Increased disturbance was associated with shifts from stress tolerant species to ruderal plants characterized by more acquisitive traits, including shorter plants with greater Specific Leaf Area. The research demonstrates the severity of impacts from off trail trampling including how trampling favours some species with specific traits over others and why it is important to limit off track use in areas of high conservation value.

Hiking trails as conduits for the spread of non-native species in mountain areas

Roadsides are major pathways of plant invasions in mountain regions. However, the increasing importance of tourism may also turn hiking trails into conduits of non-native plant spread to remote mountain landscapes. Here, we evaluated the importance of such trails for plant invasion in five protected mountain areas of southern central Chile. We therefore sampled native and non-native species along 17 trails and in the adjacent undisturbed vegetation. We analyzed whether the number and cover of non-native species in local plant assemblages is related to distance to trail and a number of additional variables that characterize the abiotic and biotic environment as well as the usage of the trail. We found that non-native species at higher elevations are a subset of the lowland source pool and that their number and cover decreases with increasing elevation and with distance to trails, although this latter variable only explained 4–8% of the variation in the data. In addition, non-native richness and cover were positively correlated with signs of livestock presence but negatively with the presence of intact forest vegetation. These results suggest that, at least in the region studied, hiking trails have indeed fostered non-native species spread to higher elevations, although less efficiently than roadsides. As a corollary, appropriate planning and management of trails could become increasingly important to control plant invasions into mountains in a world which is warming and where visitation and recreational use of mountainous areas is expected to increase.

Soil carbon enhancing practices: a systematic review of barriers and enablers of adoption

Sustained adoption of soil carbon enhancing practices (SCEPs) at scale remains an aspiration goal to maintain sufficient amount of soil carbon in household farms in order to impact on the sustained farm productivity caused by sustained soil fertility. The objective of this study is to systematically evaluate the current evidence base to identify: (a) which factors enable or constrain adoption of SCEPs and hence maintain soil carbon in Kenya and Ethiopia; (b) to be able to lessons learnt concerning what influences the adoption of the SCEPs for the purpose of maintaining soil fertility among smallholder farms; and (c) how this can be improved going into the future for the purpose of formulating appropriate policies in Kenya and Ethiopia in both the short and long run. A systematic review was conducted using established review methodology and extensive searches of published and unpublished literature sources. Data extraction and quality appraisal of quantitative, qualitative and case studies that met the inclusion criteria were conducted while checking for reliability. A broad range of interrelated enabling and constraining factors was identified for the SCEPs. All the factors matter, and some of most of these factors are important to be considered during planning and implementation of SCEPs aiming at promoting soil carbon sequestration. Despite the limitation in the quantity of evidence, this systematic review provides a useful starting point for the scaling up programmes to ensure more effective adoption of SCEPs. This review also underscores the need for a multidisciplinary approach in understanding what determines the adoption of SCEPs to capture a holistic view.

Nature Conservation and Nature-Based Tourism: A Paradox?

Throughout the world, areas have been reserved for their exceptional environmental values, such as high biodiversity. Financial, political and community support for these protected areas is often dependent on visitation by nature-based tourists. This visitation inevitably creates environmental impacts, such as the construction and maintenance of roads, tracks and trails; trampling of vegetation and erosion of soils; and propagation of disturbance of resilient species, such as weeds. This creates tension between the conservation of environmental values and visitation. This review examines some of the main features of environmental impacts by nature-based tourists through a discussion of observational and manipulative studies. It explores the disturbance context and unravels the management implications of detecting impacts and understanding their causes. Regulation of access to visitor areas is a typical management response, qualified by the mode of access (e.g., vehicular, ambulatory). Managing access and associated impacts are reviewed in relation to roads, tracks and trails; wildlife viewing; and accommodations. Responses to visitor impacts, such as environmental education and sustainable tour experiences are explored. The review concludes with ten recommendations for further research in order to better resolve the tension between nature conservation and nature-based tourism.

Walking in Each Other’s Footsteps: Do Animal Trail Makers Confer Resilience against Trampling Tourists?

Modern humans, and other hominins before them, have walked across the landscapes of most continents for many millennia. They shared these landscapes with other large animals, especially mammalian herbivores and their predators, whose footsteps defined trails through the vegetation. Most of the diversity in the wild species is now concentrated in protected areas and visited by large numbers of tourists who may walk amongst them. This review examines the literature about medium-large animal and tourist trampling impacts to uncover any marriage between animal ecology and nature-based tourism research. Methodology is comparable. Animal ecology has focused on the propagation of grazing and trampling effects from a point source (usually water). Tourism research has focused on trail structure (formal/informal, hardened, wide/narrow) and the propagation of effects (especially weeds) into the hinterland and along the trail. There is little research to substantiate an evolutionary view of trampling impacts. At least tourists venturing off formed trails may reduce impacts by following animal trails with caveats, such as risk of encounters with dangerous animals and disruption of animal behavior. This is an under-studied topic but a fertile ground for research, aided by modern tools like trail cameras and geographically enabled devices borne by tourists.

Recreational Ecology: A Review of Research and Gap Analysis

Recreational ecology is an internationally evolving research field addressing the high demand for nature-based tourism and recreation, and its environmental impacts. This review aimed to analyze the research effort of recreational ecology studies published in four renowned journals in the field, the Journal of Sustainable Tourism, Tourism Management, the Journal of Environmental Management, and Environmental Management. Between 1976 and 2017, this review identified 145 papers focused on recreational ecology. The majority of research investigated the direct impacts of terrestrial activities in protected areas, in particular the impacts of walking and hiking on vegetation and trail conditions, and the impacts of wildlife viewing. A conceptual model was developed to describe the varied relationships between nature-based tourists and recreationists and the environment. Future research in recreational ecology should broaden its agenda to increase knowledge on indirect and long-term impacts; including on cryptic or less popular species; establish more specifically how the intensity of impacts depends on the amount of use other than in trampling studies; extend to other geographic areas such as developing countries, and nature-based spaces that are less protected and exposed to high visitation such as urban environments. Importantly, a much stronger focus needs to be on interdisciplinary approaches incorporating both environmental and social science techniques to determine ways of how visitor experiential needs can be reconciled with environmental conservation concerns in a rapidly increasing tourism and recreation economy.

Using crowd-sourced photos to assess seasonal patterns of visitor use in mountain-protected areas

Managing protected areas effectively requires information about patterns of visitor use, but these data are often limited. We explore how geotagged photos on Flickr, a popular photo-sharing social-media site, can generate hotspot maps and distribution models of temporal and spatial patterns of use in two mountain-protected areas of high conservation value. In Aconcagua Provincial Park (Argentina), two routes to the summit of Aconcagua were used in summer, but most visitors stayed close to the main road, using formal and informal walking trails and the Visitor Centre, while in winter, there was very limited visitation. In Kosciuszko National Park (Australia), alpine walking trails were popular in summer, but in winter, most visitors stayed in the lower altitude ski resorts and ski trails. Results demonstrate the usefulness of social-media data alone as well as a complement for visitor monitoring, providing spatial and temporal information for site-specific and park-level management of visitors and potential impacts in conservation areas.

Local trampling disturbance effects on alpine plant populations and communities: Negative implications for climate change vulnerability

Global change is modifying species communities from local to landscape scales, with alterations in the abiotic and biotic determinants of geographic range limits causing species range shifts along both latitudinal and elevational gradients. An important but often overlooked component of global change is the effect of anthropogenic disturbance, and how it interacts with the effects of climate to affect both species and communities, as well as interspecies interactions, such as facilitation and competition. We examined the effects of frequent human trampling disturbances on alpine plant communities in Switzerland, focusing on the elevational range of the widely distributed cushion plant Silene acaulis and the interactions of this facilitator species with other plants. Examining size distributions and densities, we found that disturbance appears to favor individual Silene growth at middle elevations. However, it has negative effects at the population level, as evidenced by a reduction in population density and reproductive indices. Disturbance synergistically interacts with the effects of elevation to reduce species richness at low and high elevations, an effect not mitigated by Silene. In fact, we find predominantly competitive interactions, both by Silene on its hosted and neighboring species and by neighboring (but not hosted) species on Silene. Our results indicate that disturbance can be beneficial for Silene individual performance, potentially through changes in its neighboring species community. However, possible reduced recruitment in disturbed areas could eventually lead to population declines. While other studies have shown that light to moderate disturbances can maintain high species diversity, our results emphasize that heavier disturbance reduces species richness, diversity, as well as percent cover, and adversely affects cushion plants and that these effects are not substantially reduced by plant-plant interactions. Heavily disturbed alpine systems could therefore be at greater risk for upward encroachment of lower elevation species in a warming world.

Economic effects of ocean acidification: Publication patterns and directions for future research

Human societies derive economic benefit from marine systems, yet these benefits may be modified as humans drive environmental change. Here, we conducted the first systematic review of literature on the potential economic effects of ocean acidification. We identified that while there is a growing literature discussing this topic, assessments of the direction and magnitude of anticipated economic change remain limited. The few assessments which have been conducted indicate largely negative economic effects of ocean acidification. Insights are, however, limited as the scope of the studies remains restricted. We propose that understanding of this topic will benefit from using standard approaches (e.g. timescales and emissions scenarios) to consider an increasing range of species/habitats and ecosystem services over a range of spatial scales. The resulting understanding could inform decisions such that we maintain, or enhance, economic services obtained from future marine environments.

How Networks of Informal Trails Cause Landscape Level Damage to Vegetation

When visitors are not constrained to remain on formal trails, informal trail networks can develop and damage plant communities in protected areas. These networks can form in areas with low growing vegetation, where formal trails are limited, where there is limited regulation and where vegetation is slow to recover once disturbed. To demonstrate the extent of impacts from unregulated recreational use, we assessed damage to alpine vegetation by hikers and pack animals in the highest protected area in the southern Hemisphere: Aconcagua Park, in the Andes. Within the 237 ha area surveyed in the Horcones Valley, over 19 km of trails were found, nearly all of which (94%) were informal. This network of trails resulted in the direct loss of 11.5 ha of vegetation and extensive fragmentation of alpine meadows (21 fragments) and steppe vegetation (68 fragments). When levels of disturbance off these trails were quantified using rapid visual assessments, 81% of 102 randomly located plots showed evidence of disturbance, with the severity of disturbance greatest close to trails. As a result, vegetation in 90% of the Valley has been damaged by visitor use, nearly all of it from unregulated use. These results highlight the extent to which informal trails and trampling off-trail can cause landscape damage to areas of high conservation value, and hence the importance of better regulation of visitor use. The methodology used for off-trail impact assessment can be easily applied or adapted for other popular protected areas where trampling off-trail is also an issue.