Mapping the Research Landscape of Soil Erosion in Protected Areas: A Systematic Bibliometric Analysis

Abstract

Soil erosion is a pressing global environmental challenge that threatens ecosystem stability, water quality, and biodiversity. While much research has focused on agricultural landscapes, erosion processes within protected areas have received comparatively less attention, despite their implications for conservation and the provision of ecosystem services. This study presents a comprehensive bibliometric analysis of 527 Scopus-indexed journal articles on soil erosion in protected areas and follows the PRISMA protocol. The analysis maps the thematic structure of the field, highlights influential publications and dissemination outlets, and examines global collaboration patterns. Results show a steady growth in research output and a thematic evolution from process-focused, site-specific studies toward integrated approaches that connect erosion processes with ecosystem services, sustainability, and advanced geospatial tools. Influential works draw on two complementary intellectual pillars, namely recreation ecology and soil conservation science. Knowledge dissemination takes place through a diverse range of journals, while collaboration networks link both regional partnerships and transcontinental connections. These findings provide a roadmap for enhancing the scientific and practical relevance of research in this field.

1. Introduction

Soil erosion, the detachment and movement of soil particles by agents such as water, wind, or gravity, is a major global environmental concern [1]. Although erosion is a natural geomorphic process, human activities have accelerated its rate far beyond natural baselines, undermining ecosystem stability, agricultural productivity, and landscape integrity [2,3]. Around the world, it contributes to the loss of fertile topsoil, sedimentation of rivers and reservoirs, declines in water quality, and reductions in biodiversity [4,5]. Current estimates indicate that more than 75 billion tonnes of soil are lost each year, with the most severe rates occurring in areas undergoing rapid land use change, deforestation, or unsustainable management practices [3].

Protected areas are not exempt from the threat of soil erosion [6]. Researchers and park managers consider soil erosion one of the most significant problems in protected areas [7]. Restoring eroded sites is often costly and competes for limited resources needed for other critical conservation priorities [8].

Research on soil erosion in protected areas is substantial yet highly diverse, spanning multiple disciplines such as geomorphology, recreation ecology, conservation biology, and environmental management [9]. Scholars have quantified erosion rates, investigated environmental and use-related drivers, developed spatial models to predict erosion-prone areas, and assessed the effectiveness of management interventions [10,11]. Building on this foundation, a growing number of systematic reviews have sought to synthesize the global research landscape on soil erosion. However, most of these have concentrated on agricultural systems or watershed-scale processes [12], and none has specifically consolidated knowledge within the context of protected areas.

This bibliometric study addresses that gap by providing a data-driven synthesis of scholarship on soil erosion in protected areas. Through mapping publication trends, thematic clusters, influential works, and collaboration networks, bibliometric analysis can illuminate the intellectual structure and evolution of the field. Specifically, this study aims to:

(1)

examine temporal growth patterns and subject area distribution of publications,

(2)

identify major thematic areas and emerging research trends,

(3)

determine the most influential publications and their intellectual foundations,

(4)

analyze leading publication outlets and the scope of research, and

(5)

assess the geographical distribution of studies and patterns of collaboration.

The findings will offer a consolidated knowledge base that provides both scholarly insight and practical guidance for managing and mitigating soil erosion in some of the world’s most valued and ecologically significant landscapes.

2. Literature Review

Protected areas are legally designated to conserve natural landscapes and safeguard biodiversity and ecological integrity. However, they are not immune to the factors that drive soil erosion [2,3]. In protected areas, soil erosion arises from both natural processes and human activities, particularly those linked to recreation, tourism, and infrastructure development [13,14].

Soil erosion in protected areas differs from agricultural landscapes where erosion is typically diffuse, associated with tillage, crop harvesting, and removal of ground cover [15,16]. In contrast, erosion in protected areas is often spatially concentrated, occurring at specific locations where human activity or infrastructure disrupts surface stability [4,5].

Common hotspots of erosion in these environments include recreational trails, unpaved roads, campsites, riverbanks, and construction zones for visitor facilities [17]. Such features create exposed surfaces by removing vegetation and litter, compacting soil, and concentrating surface runoff [7,18]. Trails and roads, by their linear form, channel water flow and increase its velocity, amplifying erosive forces [19]. Campsites and picnic areas contribute through soil compaction and vegetation loss, while riverbanks can experience accelerated erosion due to visitor access and altered hydrological regimes [13]. Soil erosion is especially common and severe on steep slopes or in regions with high rainfall [20].

The severity of erosion in protected areas varies widely with climate, soil type, topography, visitor pressure, and management strategies [21]. Alpine and montane parks, for example, are prone to rapid incision and gullying on steep slopes under high rainfall [22]. Tropical reserves face intense wet-season erosion driven by fragile soils and heavy precipitation [17]. Arid and semi-arid protected areas, although experiencing infrequent rainfall, can suffer severe erosion during episodic storms, with slow vegetation recovery [23]. The ecological consequences extend beyond soil loss, contributing to habitat fragmentation, sedimentation of aquatic ecosystems, spread of invasive species, and declines in biodiversity [24]. These impacts also diminish visitor experiences and increase maintenance costs, placing additional strain on limited conservation resources [25].

Research on soil erosion in protected areas can be broadly grouped into four interconnected domains. The first domain focuses on quantifying soil loss rates, mapping erosion features, and establishing baseline conditions. Traditional field-based techniques such as erosion pins, profile boards, and cross-sectional surveys provide accurate local measurements but are often labor-intensive [26,27]. To enable rapid assessments across extensive trail and road networks, visual survey protocols have been developed [28]. Advances in technology, including GPS mapping, remote sensing, and unmanned aerial vehicles (UAVs), have expanded spatial coverage and improved precision, allowing managers to monitor changes over time more effectively [29].

The second domain examines the interaction between environmental and anthropogenic factors that influence erosion in protected areas. Key environmental variables include slope, soil texture, drainage patterns, and vegetation cover, while anthropogenic factors encompass visitor numbers, activity types, and infrastructure design [18]. Steep gradients and poorly drained alignments concentrate runoff, increasing its erosive power [14]. Soil compaction from trampling or vehicular traffic reduces infiltration, and vegetation removal decreases soil cohesion, making surfaces more susceptible to detachment [24].

The third domain addresses visualization and modeling, with Geographic Information Systems (GIS) and spatial modeling serving as essential tools. By integrating field measurements with spatial datasets such as slope, aspect, soil type, and vegetation cover, GIS analyses can identify areas at high risk of erosion [29]. Predictive approaches, including the Universal Soil Loss Equation (USLE) and its revised version (RUSLE), have been adapted to model linear features like trails and roads [30]. High-resolution digital elevation models (DEMs) derived from UAV photogrammetry enhance hydrological modeling and improve the accuracy of erosion risk assessments [29,31].

The fourth domain focuses on management strategies aimed at preventing, mitigating, or restoring erosion damage. Preventive measures include sustainable trail and road design, maintaining grades below recommended thresholds, incorporating drainage features, and choosing routes that avoid sensitive soils [7]. Mitigation efforts may involve surface hardening, installing water bars, or re-routing problematic segments. Restoration techniques can include revegetation, recontouring, and the application of geotextiles for stabilization [32]. Adaptive management frameworks integrate monitoring results into decision-making to ensure that interventions remain effective under changing conditions [33].

Only a small number of narrative reviews have addressed soil erosion in protected areas, and these have typically appeared within broader discussions of recreation impacts. For example, one of the earliest syntheses of backcountry recreation effects, identifying soil erosion as a primary concern and outlining associated management practices [34]. Another review examined the impacts of trail infrastructure on soils and vegetation, highlighting that most studies are geographically concentrated in developed countries and that significant gaps remain in tropical and arid regions [33].

By contrast, existing bibliometric reviews on soil erosion have largely focused on agricultural systems [35], erosion modeling [36], or land degradation in general [37]. No study has yet mapped the research landscape of soil erosion specifically within protected areas. This gap is important, as bibliometric analysis can reveal the thematic structure, intellectual foundations, and collaboration patterns of the field. The present study addresses this need by providing a comprehensive bibliometric mapping of the literature on soil erosion in protected areas. Filling this gap is essential for developing an integrated perspective that captures the multifaceted nature of the field and supports future research agendas, management practices, and policy development.

3. Methodology

3.1. Data Collection

This study adopts a systematic approach to data collection and analysis, consistent with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines [38]. The PRISMA flow diagram (Figure 1) illustrates the article selection process.

The Scopus database was selected for data collection for three main reasons. First, Scopus is the largest abstract and citation database of peer-reviewed literature in terms of the number of records, providing comprehensive coverage across a wide range of disciplines [39]. Second, the database includes only scholarly sources that adhere to established peer-review and publication standards, ensuring high-quality data [40]. Third, Scopus integrates seamlessly with VOSviewer (version 1.6.20), the bibliometric visualization software used in this study, enabling efficient export and analysis of metadata.

The data query was conducted on 27 July 2025. Three search criteria were applied:

(1)

Search terms: (“soil erosion” OR “soil loss”) AND (“park” OR “protected area”) were searched within the Title, Abstract, and Keywords fields. This criterion ensures that the selected publications explicitly address soil erosion in the context of protected areas.

(2)

Source type: The search was limited to journal sources. This criterion ensures the inclusion of studies published in reputable, peer-reviewed outlets.

(3)

Document type: Only articles were included, excluding conference papers, reviews, and other formats. This restriction ensures the dataset consists of original research contributions.

The initial query yielded 650 records. 93 non-journal records and 30 non-article records were excluded, leaving 527 records for screening. Screening and eligibility were assessed at the metadata level (titles, abstracts, and keywords), as is standard in bibliometric analysis. No further exclusions were required, and the final dataset comprised 527 journal articles, which formed the basis for subsequent bibliometric analysis.

3.2. Data Analysis

The dataset was cleaned by standardizing author names, keywords, and institutional affiliations, and by merging synonymous terms in the thesaurus to ensure consistency in bibliometric mapping.

The bibliometric analysis included two components. First, performance analysis evaluates the influence or productivity of documents, authors, institutions, and countries. Excel spreadsheets (Microsoft 365, Version 2308) were used to summarize publication counts, citation numbers, keywords, authorship patterns, sources, and geographic distribution. Second, science mapping reveals the structural and dynamic aspects of the research field. This study employed four bibliometric techniques:

(1)

Co-occurrence analysis explores major research themes and trends based on the frequency with which keywords appear together.

(2)

Co-citation analysis explores the intellectual foundation by detecting documents that are cited together by other works.

(3)

Bibliographic coupling analysis explores relationships between journals that cite the same source, characterizing the scopes of dissemination outlets.

(4)

Co-authorship analysis explores collaborative relationships among countries.

Science mapping results were visualized as network maps using VOSviewer. In these maps, nodes represent bibliometric items such as authors, keywords, or publications, and their positions are determined by minimizing the weighted sum of squared Euclidean distances between them. Node size indicates the frequency or magnitude of the bibliometric item, line thickness reflects the strength of a link, and proximity shows the degree of relatedness. Nodes are color-coded into clusters based on similarity measures, with each cluster interpreted as a theme, intellectual foundation, scope, or collaboration network, depending on the bibliometric context.

4. Results

4.1. Research Output and Subject Areas

Figure 2 shows an upward trajectory in research output on soil erosion in protected areas since the first article appeared in 1969. Prior to 1991, output remained minimal, rarely exceeding five articles per year. This early stage likely reflects the narrow research scope of the period, when soil erosion was studied primarily in agricultural or watershed contexts rather than within conservation areas [3,15,16].

A moderate increase occurred between 1992 and 2010, coinciding with the expansion of ecological monitoring programs in protected areas and the growing recognition of soil erosion as an important indicator of ecological integrity [41].

After 2010, publication numbers rose sharply, with annual totals surpassing 20 articles in most years after 2013. This growth aligns with the broader adoption of remote sensing, GIS, and modeling techniques in geomorphology and conservation management [29], as well as the influence of global conservation frameworks that emphasize ecosystem services such as soil retention [42]. The peak was reached in 2023 with 48 publications, indicating that soil erosion in protected areas has emerged as a prominent research theme in conservation science. The subsequent decline in 2024, to 34 publications, may reflect a combination of indexing delays and year-to-year fluctuations, rather than a substantive reduction in research activity. The partial count for 2025 (up to 27 July) reinforces that interpretation.

The literature on soil erosion in protected areas spans a wide range of subject areas, reflecting the inherently interdisciplinary nature of the field. As shown in

Table 1. Subject areas of articles on soil erosion in protected areas.

Rank (nth)	Subject Area 1	Number of Articles 2
1	Environmental Science	317
2	Agricultural and Biological Sciences	219
3	Earth and Planetary Sciences	156
4	Social Sciences	106
5	Engineering	30
6	Energy	24
7	Biochemistry, Genetics and Molecular Biology	16
8	Computer Science	15
9	Multidisciplinary	11

¹ Only the subject areas that have at least 10 articles are shown; ² The total count is larger than the total number of articles because some articles belong to more than one subject area.

, most publications are classified under Environmental Sciences (317 articles), followed by Agricultural and Biological Sciences (219 articles) and Earth and Planetary Sciences (156 articles). These dominant categories highlight the core disciplinary anchors of soil erosion research. Environmental sciences provide the overarching framework for understanding erosion processes within ecosystems, agriculture-related research contributes methodological approaches and soil conservation expertise, and earth sciences offer geomorphological and hydrological perspectives [43].

A notable proportion of studies (106 articles) falls within the Social Sciences, underscoring the increasing recognition of human dimensions in soil erosion management in protected areas. Research in this category often addresses community engagement, policy frameworks, and visitor management in recreational landscapes [44].

Several other subject areas, though less represented, indicate meaningful cross-disciplinary linkages. Engineering (30 articles) includes studies on erosion control structures, drainage systems, and slope stabilization. Energy (24 articles) reflects work examining the effects of soil erosion on hydropower and renewable energy development. Biochemistry, Genetics and Molecular Biology (16 articles) focuses on soil microbial communities and nutrient cycling. Computer Science (15 articles) highlights the use of computational modeling, remote sensing, and machine learning for erosion prediction. The Multidisciplinary category (11 articles) captures research that explicitly integrates approaches across several domains. The number of articles in other subject areas is less than 10.

4.2. Keywords

The analyzed articles on soil erosion in protected areas contained 1774 distinct keywords, of which 21 appeared at least 30 times (

Table 2. Most frequently occurred keywords on soil erosion in protected areas.

Rank (nth)	Keyword 1	Occurrences
1	soil erosion	260
2	soils	108
3	erosion	78
4	protected area	72
5	environmental protection	55
6 to 7	national park; soil conservation	50
8	GIS	48
9 to 10	biodiversity; China	47
11	land use	46
12	runoff	43
13 to 14	climate change; forestry	37
15	vegetation	36
16	ecosystem service	35
17 to 19	conservation; environmental monitoring; United States	34
20	land use change	33
21	remote sensing	31

¹ Only the keywords that occurred at least 30 times are shown.

). These frequently occurring terms offer an outlook of the breadth and core concepts of the research field. “Soil Erosion” (260 occurrences), “Soils” (108 occurrences), and “Erosion” (78 occurrences) are dominant keywords in the field.

There are some keywords linked to the conservation context, including protected area (72 occurrences), national park (50 occurrences), environmental protection (55 occurrences), soil conservation (50 occurrences), and conservation (34 occurrences). These keywords highlight that much of this research is situated within formally designated conservation areas, where soil erosion is often studied as a management concern affecting ecological integrity and visitor infrastructure [7,19].

Several keywords are methodologically oriented, such as GIS (48 occurrences) and remote sensing (31 occurrences), indicating the widespread use of geospatial technologies for mapping and monitoring the erosion risk [29,31]. Environmental monitoring (34 occurrences) captures studies on systematic data collection to track erosion trends.

A few keywords are linked to ecology, such as biodiversity (47 occurrences), runoff (43 occurrences), vegetation (37 occurrences), and ecosystem service (35 occurrences), suggesting a multidisciplinary framing that connects soil erosion with habitat health, hydrological processes, and the provisioning of ecosystem services [45].

Broader global change drivers, such as climate change (37 occurrences), land use (46 occurrences), and land use change (33 occurrences), are present, showing that erosion in protected areas is studied within the context of anthropogenic pressures and environmental change [7].

Finally, geographic focus is visible through country and region terms such as China (47 occurrences) and United States (34 occurrences), reflecting that these two countries are key contributors to the literature.

Co-occurrence analysis was performed to examine the thematic relationships between keywords. Twenty-seven keywords, each appearing at least five times in the literature, were grouped into five clusters (Figure 3). The most prominent node, soil erosion, positioned at the center of the network map, underscores its pivotal role in the knowledge structure. All other keywords connect directly or indirectly to it, reflecting its integrative function across thematic areas.

The red cluster, “Erosion Processes,” comprises keywords such as runoff, soil, disturbance, land use change, and USLE. These terms indicate a focus on the physical mechanisms of soil erosion, as described and quantified by USLE. Keywords like disturbance and land use change highlight anthropogenic and environmental drivers [3], while USLE and rainfall simulation point to methodological approaches foundational to erosion studies [30,46]. Strong internal linkages within this cluster suggest that researchers frequently integrate process-based modeling with field experimentation.

The green cluster, “Ecological Impacts and Ecosystem Services,” includes keywords such as biodiversity, ecosystem service, erosion control, sediment, trail, and water quality. This grouping links soil erosion to the wider ecosystem services of protected areas. The presence of trail underscores its role as a key source of soil disturbance in recreational settings [18,22], while the connection between water quality and sediment reflects an integrated view of erosion as both a terrestrial and aquatic management challenge.

The blue cluster, “Global Challenges,” offers a broader perspective on environmental change, incorporating keywords such as soil erosion, climate change, fire, conservation, human impact, and vegetation. Terms like climate change, fire, and human impact point to recognition of the ways natural disturbances and visitor activities can accelerate erosion in protected landscapes [12,47].

The yellow cluster, “Geoinformatic Technology,” contains GIS, remote sensing, RUSLE, land use, and sedimentation. This is a clearly methods-oriented group, emphasizing spatial analysis, modeling tools, and geospatial technologies for monitoring and predicting erosion patterns [48]. The combination of GIS and remote sensing with modeling approaches such as RUSLE reflects a growing trend toward large-scale, data-driven assessments in protected areas [49].

The purple cluster, “Sustainability,” is smaller and includes protected area, soil conservation, and sustainability. These terms represent the governance and policy-oriented dimension of the research, framing erosion management within the broader objectives of protected landscape stewardship [50].

A temporal overlay visualization further reveals how research interests within the field have evolved over time (Figure 4). Earlier interests, represented by purple and dark blue keywords, concentrated on foundational topics such as disturbance, rainfall simulation, runoff, soil, land use change, and USLE. These keywords reflect the initial emphasis on quantifying erosion processes, understanding the physical mechanisms, and applying empirical models under various environmental and land use conditions [51,52].

Over time, green-shaded keywords such as protected area, soil conservation, biodiversity, ecosystem service, climate change, and conservation emerged more prominently. This marks a transition from purely biophysical process studies toward integrating ecological and conservation perspectives. The inclusion of biodiversity and ecosystem service indicates that soil erosion was increasingly framed as a threat to ecosystem integrity and human well-being, aligning with the broader ecosystem services discourse [41,45]. The prominence of protected area reflects the growing management imperative in conservation contexts, while climate change denotes the recognition of global environmental change as an important driver of erosion dynamics [12].

The yellow keywords include remote sensing, GIS, RUSLE, sedimentation, sustainability, and land use, representing the recent shifts toward technological, management, and sustainability-oriented approaches. This trend illustrates the incorporation of advanced geospatial technologies, spatial modeling, and integrated management frameworks to assess and mitigate erosion at larger scales [29,31]. The rise in sustainability as a frequent term underscores the alignment of erosion research with global sustainability agendas, such as the UN Sustainable Development Goals [53], which stress the importance of soil conservation in biodiversity protection, water quality maintenance, and climate resilience.

4.3. Documents

Among the 527 studied articles, 17 were cited more than 100 times (

Table 3. Highly cited documents on soil erosion in protected area.

Rank (nth)	Document 1	Title	Year	Journal	Citations
1	Fu et al. [54]	Effects of land use and climate change on ecosystem services in Central Asia’s arid regions: A case study in Altay Prefecture, China	2017	Science of the Total Environment	251
2	Ochoa et al. [55]	Effects of climate, land cover and topography on soil erosion risk in a semiarid basin of the Andes	2016	Catena	194
3	Dunjó et al. [56]	Land use change effects on abandoned terraced soils in a Mediterranean catchment, NE Spain	2003	Catena	183
4	Wang & Dai [60]	Spatial-temporal changes in ecosystem services and the trade-off relationship in mountain regions: A case study of Hengduan Mountain region in Southwest China	2020	Journal of Cleaner Production	178
5	Moreno et al. [61]	Agroforestry systems of high nature and cultural value in Europe: provision of commercial goods and other ecosystem services	2018	Agroforestry Systems	149
6	Zhou et al. [62]	Hydrological impacts of reafforestation with eucalypts and indigenous species: A case study in southern China	2002	Forest Ecology and Management	143
7	Olive & Marion [10]	The influence of use-related, environmental, and managerial factors on soil loss from recreational trails	2009	Journal of Environmental Management	143
8	Barger et al. [63]	Impacts of biological soil crust disturbance and composition on C and N loss from water erosion	2006	Biogeochemistry	142
9	McClanahan & Obura [64]	Sedimentation effects on shallow coral communities in Kenya	1997	Journal of Experimental Marine Biology and Ecology	138
10	Jordan et al. [57]	Historical land use changes and their impact on sediment fluxes in the Balaton basin (Hungary)	2005	Agriculture, Ecosystems and Environment	133
11	Wang et al. [65]	Evaluation of the comprehensive carrying capacity of interprovincial water resources in China and the spatial effect	2019	Journal of Hydrology	131
12	Allen & Sorbel [66]	Assessing the differenced Normalized Burn Ratio’s ability to map burn severity in the boreal forest and tundra ecosystems of Alaska’s national parks	2008	International Journal of Wildland Fire	123
13	Mati et al. [58]	Impacts of land use/cover changes on the hydrology of the transboundary Mara River, Kenya/Tanzania	2008	Lakes and Reservoirs: Science, Policy and Management for Sustainable Use	121
14	Szilassi et al. [59]	Impacts of historical land use changes on erosion and agricultural soil properties in the Kali Basin at Lake Balaton, Hungary	2006	Catena	113
15	Maikhuri et al. [67]	Analysis and resolution of protected area-people conflicts in Nanda Devi Biosphere Reserve, India	2000	Environmental Conservation	111
16	Medley et al. [68]	Landscape change with agricultural intensification in a rural watershed, southwestern Ohio, USA	1995	Landscape Ecology	109
17	Vanwalleghem et al. [69]	A quantitative model for integrating landscape evolution and soil formation	2013	Journal of Geophysical Research: Earth Surface	104

¹ Only the articles with more than 100 citations are shown.

). Despite the diversity of topics covered in these articles, a few patterns which echo the thematic findings of the keyword co-occurrence analysis are identified. First, the dominance of land use and climate change themes is evident. Specifically, six out of the seventeen most cited articles investigate the effects of land use and/or climate change on various aspects of soil erosion [54,55,56,57,58,59]. This aligns with broader literature emphasizing the intertwined roles of anthropogenic land transformations and climate variability in shaping soil erosion dynamics, especially in vulnerable landscapes [52].

Second, geographical diversity is a defining characteristic. Highly cited works span diverse ecosystems, ranging from semiarid Andean basins [55] to Mediterranean terraced catchments [56], Alaska tundra [66] to tropical reserve [67], and various regions in China [54,60,62]. This geographic breadth reflects the global relevance of soil erosion issues in protected areas, yet also points to region-specific processes and management challenges.

Third, integration of ecosystem services and conservation values is a recurring focus. Some studies frame soil erosion within broader conservation, livelihood, and socio-ecological contexts [60,61,67]. This signals a shift from purely geomorphological investigations toward multidisciplinary research linking erosion to biodiversity, livelihoods, and cultural values [42].

Finally, cross-sectoral drivers such as hydrological change and fire regimes are also popular in this field [58,66], indicating that integrated approaches are also valued by the academic community.

Co-citation analysis was conducted to identify the clusters which represent the coherent intellectual foundation of the research on soil erosion in protected areas. A total of 11 articles co-cited at least four times were grouped into two clusters (Figure 5).

The red cluster is titled “Recreation Ecology and Trail Assessment.” Early foundational contributions include work on backcountry trail condition monitoring [26] and on wildland recreation ecology and management [70,71]. These are complemented by research on methodological refinements [72], trail monitoring [27,28], and analysis of environmental, managerial, and use-related factors influencing soil loss [18]. Broader review of the ecological impacts of outdoor recreation further widens the cluster’s breadth and depth [73]. Collectively, this body of work emphasizes understanding, measuring, and mitigating recreational impacts, particularly trail erosion in protected areas, while highlighting applied management tools and field-based monitoring protocols.

The green cluster focuses on “Soil Management and Conservation Strategies.” While some studies synthesize soil management challenges and solutions [74], others focus on soil erosion and conservation [75], and still others exemplify integrated management planning in a protected area context [76]. The inclusion of the manual of R statistics [77] reflects the methodological and analytical advances that support this research area. Overall, the cluster represents a broader soil conservation and management perspective, with emphasis on conceptual frameworks, conservation planning, and the application of statistical tools for data analysis.

4.4. Journals

The 527 articles on soil erosion in protected areas were published in 290 journals.

Table 4. Productive journals on soil erosion in protected areas.

Rank (nth)	Journal 1	Articles
1	Catena	17
2	Journal of Environmental Management	15
3	Sustainability (Switzerland)	14
4	Science of the Total Environment	13
5 to 6	Forests; Science of Soil and Water Conservation	9
7 to 8	Environmental Management; Land	8
9	Water Switzerland	7
10 to 16	Earth Surface Processes and Landforms; Ecological Engineering; Erosion Control; Journal of Hydrology; Land Degradation and Development; Scientific Reports; Shengtai Xuebao	6
17 to 18	International Journal of Environmental Research and Public Health; Remote Sensing	5

¹ Only the journals that published at least five articles are shown.

lists the most productive journals that have published at least five papers. Catena emerges as the top publishing journal with 17 articles. Known for its focus on soil science, geomorphology, and hydrological processes, Catena is a natural outlet for erosion-related studies, especially those addressing soil loss processes, modeling, and land management strategies. Journal of Environmental Management (15 articles), Sustainability (Switzerland) (14 articles), and Science of the Total Environment (13 articles) follow closely, indicating a strong policy and sustainability dimension in the research, with these journals frequently publishing applied studies on conservation measures and integrated management approaches.

Forests highlight the linkages between soil degradation, ecosystem services, and forest management, demonstrating the integration of erosion studies into the contexts of forest and national parks. The presence of Land, Water, and Earth Surface Processes and Landforms reflect a solid representation in land use science and hydrological modeling domains, while Ecological Engineering and Environmental Management underscore the application of engineering solutions and adaptive management to mitigate erosion in sensitive areas.

Some journals cater to highly specific audiences, such as Science of Soil and Water Conservation and Erosion Control, which focus on technical and applied aspects of erosion mitigation, and Shengtai Xuebao (Acta Ecologica Sinica), which emphasizes Chinese-language publications reflecting regional priorities in protected area conservation. The inclusion of Remote Sensing aligns with the increasing reliance on geospatial technologies for monitoring erosion patterns and impacts.

The bibliographic coupling analysis, which examined journals contributing to the literature on soil erosion in protected areas, identified 36 journals with at least three times of bibliographic coupling, grouped into five distinct clusters (Figure 6). Each cluster reflects thematic and scopic affinities among journals.

The red cluster represents a “Land-multidisciplinary” domain that integrates geomorphology, forestry management, hydrological processes, and land-use policy within soil erosion research. Key journals in this area include Sustainability (Switzerland), Forests, Land, Land Degradation and Development, Earth Surface Processes and Landform, and Land Use Policy. This cluster places strong emphasis on the physical processes of erosion, its drivers (e.g., deforestation, land use change), and land management strategies for conservation areas.

The green cluster includes Science of the Total Environment, Journal of Cleaner Production, International Journal of Environmental Research and Public Health, Scientific Reports, Water, Ecological Indicators, Landscape Ecology, PeerJ, and Shengtai Xuebao. This cluster, which can be described as “broader environmental research,” integrates studies on soil erosion in protected areas within a wider environmental framework.

The blue cluster, “environmental management and assessment,” encompasses Journal of Environmental Management, Environmental Management, Environmental Monitoring and Assessment, Journal of Environmental Studies, and Ecopersia. This cluster focuses on applied environmental management, conservation planning, and policy-driven erosion mitigation. This group of journals bridges biophysical erosion research with planning and governance approaches, reflecting bibliographically coupled work that frequently addresses management frameworks, mitigation interventions, and monitoring in protected landscapes.

The yellow cluster, “soil science,” includes Catena, Journal of Arid Environments, Ecological Engineering, Restoration Ecology, and Forest Ecology and Management. These journals are strongly aligned with soil science, ecological restoration. This cluster also includes Geoderma and Remote Sensing, reflecting an emphasis on advanced geoinformatics and spatial analysis.

Finally, the purple cluster, represented by Revista Brasileira de Geomorfologia and Soil Systems, has a narrower but more specialized focus on “soil dynamics.” This small cluster likely represents regionally concentrated research communities contributing context-specific erosion studies, particularly from Latin America and related geographies.

4.5. Countries

Figure 7 illustrates the geographic distribution of research articles on soil erosion in protected areas, revealing global leadership and distinct regional focuses. China leads the list with 99 publications, reflecting its growing scientific capacity and urgent environmental challenges in protected landscapes. Rapid economic development, extensive protected area networks, and heightened concerns about ecosystem degradation have motivated Chinese researchers to address erosion control and conservation strategies [78].

The United States follows with 82 articles, reflecting its long-standing research tradition in soil science, conservation, and recreation ecology [44]. The U.S. National Park System and related protected area agencies have been particularly active in funding and conducting studies on erosion processes and mitigation, with a focus on trails, visitor impacts, and habitat protection.

Spain (41 articles) and Australia (37 articles) reflect region-specific priorities. In Spain, face high erosion risk due to steep slopes and intensive visitor use [79]. In Australia, research indicates that soil erosion should be prioritize in the management of national parks [80]. Brazil (35 articles) emphasizes tropical protected area conservation, where soil erosion is a major cause of land degradation [17].

Germany and the United Kingdom, with 28 articles each, contribute substantially through research on soil erosion modeling, GIS applications, and conservation policy integration, often supported by European Union-funded initiatives. Italy (21 articles) and South Africa (19 articles) reflect the Mediterranean and savannah contexts, respectively, with strong emphases on erosion dynamics in biodiversity-rich protected areas.

Iran (18 articles) and India (17 articles) represent emerging contributors, frequently addressing erosion risks in mountainous national parks and protected watersheds. France (13 articles), Canada (12 articles), and Poland (10 articles) complete the list, often providing methodologically advanced or regionally focused studies that enhance global comparative analyses.

The co-authorship analysis across 31 countries reveals a network of international collaborations of soil erosion in protected areas research. There are five clusters identified (Figure 8). Each representing a set of nations with stronger collaborative ties internally than with countries outside the cluster.

The red cluster, “Trans-Atlantic Group,” is anchored by the United States, one of the most influential and well-connected hubs in the field. It also includes major research economies such as Germany, France, Switzerland, and Poland, along with South American countries like Argentina and Brazil. The dense interconnections in the diagram suggest that the United States acts as a key bridge linking European and South American research communities, often through large-scale projects, knowledge-sharing platforms, and multi-country field studies [71,81].

The green cluster, “Asia–Pacific Group,” brings together nations including China, Australia, Japan, Malaysia, and Canada. This configuration reflects both regional collaborations within the Asia–Pacific and the rise in research partnerships between developed and developing economies [82]. China’s central role in this cluster is consistent with its position as the most productive country in the field, driven by large-scale environmental challenges and significant government-funded initiatives in protected area management [78].

The blue cluster, “Commonwealth and South European Group,” includes the United Kingdom, India, South Africa, and Kenya. This network, having a good mix of high-income and lower-income countries, reflects historical ties and ongoing international collaboration [83].

The yellow cluster, “Mediterranean and Middle Eastern Group,” includes Spain, Italy, Romania, and Iran. Collaboration in this group is likely shaped by shared semi-arid to arid climatic conditions, which pose similar soil erosion challenges in protected areas [52]. Research partnerships often concentrate on practical erosion control solutions in fragile ecosystems, especially under the pressure of land use change [56].

The purple cluster, “Central and Eastern European Group,” consists of Belgium, Hungary, the Netherlands, and Portugal. Although smaller, this network is highly specialized and well regarded for methodological innovation in geomorphology and environmental monitoring. Their collaborations may be geographically limited but have significant influence in setting research standards [5].

5. Discussion

5.1. Development and Composition of the Field

The bibliometric results reveal that soil erosion research in protected areas has evolved from a marginal niche into a well-recognized interdisciplinary field over the past five decades. The sporadic publications before 1991 reflected the traditional emphasis on agricultural landscapes and watershed management [3]. The subsequent expansion in the 1990s mirrors the broader incorporation of ecological indicators into conservation monitoring programs and the recognition of soil erosion as a critical threat to ecosystem integrity [40]. The marked post-2010 surge, coinciding with the adoption of remote sensing, GIS, and modeling [29], illustrates the technological shift that has broadened research capabilities and geographic reach.

The subject area distribution further highlights the inherently interdisciplinary composition of the field. While Environmental Sciences, Agricultural and Biological Sciences, and Earth and Planetary Sciences form the disciplinary core, the notable presence of Social Sciences aligns with the recent call for integrating human dimensions into conservation science [44]. The list of productive journals and the clustering result of bibliographic coupling echoes similar findings. The interdisciplinarity of the field implies a conceptual maturity, where biophysical and socio-ecological perspectives are increasingly integrated to address complex conservation challenges [84].

5.2. Research Themes and Trends

The soil erosion research in protected areas revolves around five interconnected themes. They have developed in a mutually reinforcing way over time, responding to both methodological innovations and shifts in environmental priorities. Early work was dominated by “Erosion Processes,” with emphasis on soil loss measurement, erosion mechanism, and runoff dynamics. These process-focused studies provided the empirical and theoretical foundation for other themes. As understanding of biophysical processes deepened, researchers increasingly linked them to “Ecological Impacts and Ecosystem Services,” exploring how erosion alters biodiversity, vegetation, hydrology, and the provisioning of ecosystem services in protected landscapes. This ecological framing naturally connected with the “Global Challenges,” where soil erosion was studied alongside broader conservation goals such as biodiversity preservation, climate change mitigation, and land use policy. Here, soil erosion became one component of integrated conservation planning, especially in national parks and other high-value landscapes [10,19].

The rise in “Geoinformatic Technology,” notably GIS, remote sensing, and spatial modeling, transformed the field, enabling finer-scale erosion mapping, monitoring over time, and integration with climate and land-cover datasets. These tools bridged process-based and conservation-oriented research, making it possible to evaluate erosion risks and mitigation strategies in complex, heterogeneous protected areas. In recent years, the emergence of “Sustainability” as a distinct theme reflects a normative turn in the literature, embedding soil erosion within the larger discourse on sustainable land management and socio-ecological resilience. This has brought stronger connections to policy, participatory governance, and global sustainability frameworks [50].

The chronological patterns suggest a shift from narrowly defined physical science toward integrative, interdisciplinary approaches that combine process understanding, ecological outcomes, and governance mechanisms. Geoinformatic advances accelerated this integration, while sustainability framing has linked the field more explicitly to global policy agendas [49]. This co-evolution of themes indicates that the future trajectory of soil erosion research in protected areas will likely continue blending physical science with socio-ecological and technological perspectives, in line with broader conservation science trends [44].

5.3. Seminal Documents and Intellectual Foundation

The co-citation clusters reveal two complementary intellectual pillars of the field. One centers on recreation ecology and trail impact assessment [18,26,27], which directly addresses soil erosion as a management concern in high-use protected areas. The other focuses on soil conservation strategies and management frameworks [74,75], reflecting the broader disciplinary heritage of soil science.

Crucially, the most cited documents tend to sit at the intersection of these pillars. These papers often import the measurement rigor or modeling discipline of soil conservation while framing questions through the situational lens of recreation ecology and conservation management. For example, one study integrated climate change and land use dynamics with ecosystem service assessments in a Central Asian protected landscape, blending biophysical modeling with conservation priorities [54]. Similarly, another study examined land use change effects on erosion in a Mediterranean catchment, combining empirical soil loss measurement with management implications for semi-natural and protected areas [56]. These works illustrate how methodological robustness coupled with conservation framing tends to yield high impact. Conversely, studies that remain siloed either in technique without conservation framing, or in management rhetoric without measurement depth, are less likely to propagate as seminal works.

5.4. Geography of Soil Erosion Research in Protected Areas

The spatial distribution of research output in this field is shaped by both regional environmental imperatives and international scientific networks. A handful of countries, particularly China and the United States, emerge as dominant contributors, supported by their research infrastructure and the urgency of managing soil erosion within extensive protected landscapes. A secondary cluster, including Spain, Australia, Brazil, and Germany, also supplies significant scholarly output, often focused on regionally relevant erosion challenges.

Geographic patterns are also evident. In Mediterranean regions, notably Spain and Italy, research often addresses erosion under seasonal droughts and intense rain events, as seen in studies on soil loss dynamics in terraced arable land [56]. In tropical and biodiversity-rich zones such as Brazil, erosion research frequently intersects with ecosystem service assessment and conservation goals [17]. Research focused on mountain and high-altitude ecosystems, such as the Himalayas, often highlights the combined effects of steep terrain, fragile soils, and climate change [14].

Collaboration patterns reflect these geographic clusters. Regional networks, such as the Spain–Italy–France corridor or the Brazil–Argentina–Chile group, facilitate methodological sharing in similar environments [5]. Transcontinental partnerships, no matter of Asia-Pacific, the Commonwealth, or Trans-Atlantic collaborations, promote the exchange of knowledge and experiences. For example, comparative research on the trail environments in Australia and North America reveals shared erosion dynamics, which can inform cross-regional methodological adaptation [22].

5.5. Research Gaps and Future Directions

The thematic evolution of soil erosion research in protected areas points to several important avenues for future investigation. First, although ecosystem service concepts are increasingly invoked in the literature, empirical studies that explicitly quantify the service losses from erosion, such as reduced carbon sequestration, diminished water regulation, or biodiversity decline, are rare. Addressing this gap would allow for more robust integration of erosion control measures into conservation planning and provide decision-makers with evidence of tangible ecological and socio-economic benefits [41,45].

Second, climate change is recognized as an important driver of erosion processes, yet the incorporation of high-resolution, downscaled climate projections into erosion risk assessments for protected areas remains limited. Future studies could merge climate scenario modeling with erosion simulations to anticipate and mitigate emerging risks under changing precipitation regimes and extreme events [12].

Third, while trail erosion research has yielded valuable insights, it is often conducted in isolation from broader soil erosion studies, with different methodological frameworks and disciplinary assumptions [7,26]. This line of inquiry is largely driven by recreation ecologists who adopt different logics and methods, such as visitor behavior analysis, experimental trail design, and wear–resistance testing, compared to mainstream soil science [7,21,44]. Integrating recreation ecology perspectives with mainstream erosion modeling could yield more comprehensive assessments of localized and landscape-scale impacts, as well as more effective management strategies.

Fourth, international collaboration patterns reveal significant regional imbalances, with underrepresentation from parts of Africa, Southeast Asia, and South America despite these regions facing acute erosion risks. Expanding collaborative networks and capacity-building initiatives in these areas would enhance the global representativeness of research outputs and foster more context-specific solutions.

5.6. Practical Implications

The findings of this bibliometric analysis also hold practical value for decision-makers and protected area managers. First, the identification of long-term publication trends enables managers to anticipate emerging research priorities and incorporate them into conservation strategies. Climate change impacts, visitor management, and ecosystem restoration have emerged as key research priorities that can be translated into practical conservation measures. Second, the delineation of thematic clusters clarifies where knowledge is well established, including erosion processes and monitoring methods, and where important gaps remain, such as tropical and arid biomes or socio-ecological dimensions of erosion. This information can guide targeted investments in research, capacity building, and policy development. Third, mapping patterns of authorship and collaboration highlights opportunities for knowledge exchange and partnership, particularly across regions facing similar erosion challenges. By integrating these insights into planning and decision-making, conservation agencies can align management practices more closely with the evolving scientific evidence base and foster evidence-based strategies to mitigate soil erosion in protected landscapes.

5.7. Limitations and Recommendations

The present study is not without limitations, and these constraints provide direction for future research in the field of soil erosion in protected areas. First, the bibliometric analysis relied solely on the Scopus database. While Scopus offers extensive coverage, it does not index all relevant literature, particularly works in regional or non-English journals. This reliance may lead to the exclusion of important contributions from other databases such as Web of Science. Future research could adopt a multi-database search strategy, integrating different indexing sources to enhance coverage and reduce the risk of overlooking significant publications.

Second, the study included only peer-reviewed journal articles, excluding conference proceedings, book chapters, reports, and theses. This focus ensures consistency and quality but limits the scope, as gray literature often contains valuable case studies, technical guidelines, and policy-oriented findings relevant to soil erosion management in protected areas. Expanding the document types in future research would help create a more comprehensive understanding of the field.

Third, the bibliometric approach primarily provided quantitative indicators and network visualizations without engaging in detailed qualitative content analysis. As a result, the study identifies research patterns and linkages but does not deeply analyze the thematic nuances, methodologies, or contextual variations in the literature. Integrating bibliometric mapping with systematic content analysis in future studies could yield richer insights into the intellectual and conceptual development of the field.

Fourth, the keyword-based search strategy, while carefully constructed, may still suffer from inclusion or exclusion bias. Relevant studies may use alternative terminology or local language expressions for soil erosion and protected areas, which could result in the omission of some works. Refining search terms through controlled vocabularies, the inclusion of synonyms, and multilingual keywords could improve retrieval accuracy in subsequent studies.

6. Conclusions

This study presents a comprehensive bibliometric analysis of 527 Scopus-indexed journal articles on soil erosion in protected areas. Guided by the PRISMA protocols, it maps key research themes and trends, seminal works and intellectual foundations, dissemination outlets, and global collaboration patterns, offering a nuanced understanding of the field.

The findings show steady growth in publication output, a thematic shift from process-focused and site-specific investigations toward integrated approaches that incorporate ecosystem services, sustainability, and advanced geospatial methods. Influential works are anchored in two complementary intellectual pillars, recreation ecology and soil conservation science, while knowledge dissemination is shaped by a diverse set of journals and strong international collaborations.

The achievement of this study lies in its systematic mapping of soil erosion research in protected areas. It provides valuable insights into the field’s growth, thematic evolution, intellectual structure, and collaborative networks. These insights form a roadmap for scholars and practitioners to navigate the current research landscape, address identified gaps, and pursue future directions that enhance both the scientific and practical relevance of the field.