GLAD, Impact of urbanization, sustainable land management, Sikkim Himalaya, Land Use Land Cover.

Land-use and land-cover changes refer to the quantitative variations in the aerial extent (increases or decreases) of specific land use or land cover types. These changes can result from land conversion (a shift from one cover type to another), land modification (alterations in structure or function without a complete change from one type to another), or the maintenance of land in its current state against agents of change (Briassoulis, 2009). Land use promotes sustainability and livelihood security by contributing food, fodder and firewood in the society while the extent of forest cover on the land surface governs many crucial ecological processes and is a key factor in characterizing sustainable forest management (Gupta, 2007; Das et al., 2023). Understanding the LULC dynamics has been an impactful tool to assess the change in ecosystem structure and its land use with climate change (Hussain et al., 2024). With the process of urbanization natural ecosystems and landscapes have led to change in land-use leading to significant social and environmental challenges (Vitousek et al., 1997; Naab et al., 2013; Dar et al., 2017; Liu et al., 2019). Since 1950's the pace, degree and extent of land use and land cover changes have increased as a result of modernized human activities and therefore modifications caused by urbanization are apparent everywhere at unprecedented rates, magnitudes, and spatial scales which could have crossed the self-repair capacity of the natural ecosystem and directly affected and are reported to be the major threat to biodiversity around the globe (Turner et al., 1994; Sala et al., 2000; Lambin and Geist 2001; Hansen et al., 2013; IPBES, 2019; Kalfas et al., 2023). Previous studies have indicated that with the projected global rise in urbanization, conversions of land cover for urban development will increase, thereby altering considerable ecosystem patterns and processes (Seto et al., 2012). It has been estimated that land-use changes and their associated impacts have resulted in a global decline of local species richness by 13.6% and total abundance by 10.7% (Newbold et al., 2016, Kaur, 2017, Rai, 2017). Inevitably, urbanization has become a defining factor and one of the major driving forces shaping contemporary land use systems (Berry, 2008; Nuissl and Siedentop 2021; Zhang et al., 2024). However, there is limited knowledge about how sensitive species extinction projections are to the quality of forest cover data (Pandit et al., 2007).

Land‐use change has led to the fragmentation of natural ecosystems, with major consequences for biodiversity (Liu et al., 2019). Inevitably, understanding the dynamics of land use change is critical for efficient natural resource management, biodiversity conservation, and planning for sustainable development. In tropical regions of the world, large-scale deforestation for agriculture, forestry, wildfires, and urbanization have severely impacted biodiversity, leading to habitat loss and species decline (Mittermeier et al., 1999; Myers et al., 2000; Laurance, 2000; 2015; Sodhi and Brook 2006; Pandit et al., 2007; Miranda et al., 2024). In India, urbanization led land use change has led to ecosystem degradation, habitat destruction, resource depletion and biodiversity loss and cities  in India are facing challenges in terms of availability of green space with implications for biodiversity conservation and climate change adaptation (Uttara et al., 2012; Nagendra et al., 2014). 

Mountain areas differ from plains in various aspects, including topography, physiographic features, elevation, habitat types, diversity of flora and fauna, ethnic diversity, land use systems, and socio-economic conditions. Tiwari (2000) discussed the extensive land-use changes in the Himalayas due to population growth, leading to deforestation and expansion of cultivation, which have significant impacts on the plains' ecosystems. Rao and Pant (2001) asserted that while most studies recognize the loss of vegetal cover as a regional as well as global problem, very little was understood on a local scale about complex relationships between environmental, economic, social and natural resource policy factors that induce changes in land use. Tiwari (2008) argued that the traditional patterns of resource use in the Himalayas have undergone significant changes in recent years, primarily due to population growth and the consequent rise in demand for natural resources in the area.  

Over the past few decades, the Himalayas have experienced unprecedented land-use changes driven by rapid population growth and intensifying human activities, such as agriculture and expanding settlements (Pandit et al., 2007). In this regard, remote sensing has emerged as one of the useful tool to monitor land cover features over a period of time. The temporal dataset can provide the changes brought in by prevailing land-use practices in the region. According to Briassoulis (2009), the multiple factors of land use change operates on more than one spatial and temporal level and acts not in isolation but in intricate webs of place and time-specific relationships. Chakraborty et al. (2016) concluded that there is lack of comprehensive detailed assessments of spatial distribution of land use/land cover (LULC) change in the Indian Himalayan Region over an extended period of time.  Tiwari et al., (2018) emphasized the need for integrated urban-rural land use planning in the Himalayas to steer urbanization sustainably, advocating for effective urban land use policies for the conservation of forests, biodiversity, water resources and agricultural land.  Prakasam et al. (2018) found out that forest cover reduced from 81.58% in 1980 to 60.77% in 2017. Same way built-up land has increased from 3.59% to nearly 13.64% in the year 2017 and Agriculture land also increased from 1.91% to 16.51% in the year 2017 at Shimla Tehsil, Himachal Pradesh, Western Himalaya, India. Qadir and Singh (2019) investigated land use/cover changes in the Dal Lake catchment, Srinagar, Western Himalaya, India revealing that urban expansion and solid waste accumulation have adversely affected water quality, underscoring the environmental challenges posed by urbanization. Mishra et al, (2020) utilized remote sensing and GIS techniques to monitor LULC changes in the Rani Khola watershed of Sikkim Himalaya from 1988 to 2017 and revealed that open forest showed increasing trend during 1988-1996 whereas decreasing trend has been observed during 1996-2017. Gurung and Hannan (2021) explored the dynamics of land use change in Sikkim in relation to agricultural practices, noting transitions from traditional through conventional(green revolution) to organic farming and the associated land use implications. Digra and Kaushal (2021) have reported that the combined use of Remote Sensing (RS) with Geographic Information System (GIS) have proved as an important tool which can provide accurate data and information on LU/LC changes.  Anees et al. (2022) examined how urbanization has impacted the Himalayas through two main pathways: directly, by transforming land use and land cover to accommodate growing needs, and indirectly, through infrastructure development to support communication, transportation, and energy demands. Behera et al. (2022) emphasized that in mountainous regions, classifying land use and forest cover (LUFC) using satellite data is challenging due to the varied topography and complexities caused by differing illumination conditions. No single factor can be solely attributed to land use change. Instead, it is typically the result of a complex interplay of multiple factors including economic, social, environmental, technological and policy-related influences. Sohail and Kaushal (2023) reported that monitoring land use and land cover changes enables the implementation of appropriate control strategies for safeguarding the environment and preserving our natural resources. Haokip et al. (2023) observed that the North Eastern Region (NER) of India is equally affected by land degradation, experiencing diverse forms and intensities of environmental damage with different anthropogenic activities such as natural resource extraction, stone quarrying, oil exploration, and various industrial operations have significantly contributed to the degradation of this fragile ecosystem. Phartiyal and Sharma (2024) monitored the LULC changes (1999-2021) in the Himalayan region of Pithoragarh district, Uttarakhand, Western Himalaya and showed that vegetation and built-up have increased whereas cultivation, barren land, and snow cover have decreased. This study provided insights into the shifts in spatial and temporal patterns of landscape of Pithoragarh district. Singh et al. (2024) suggested that if the current trends of urbanization persists, the urban areas will  expand by 63% and forest cover likely to decline by around 9% by 2055 in the Western Himalayan Region. Parida et al. (2024) conducted study from 1990 to 2022 in the Behali Reserve Forest (BRF), Arunachal Pradesh, Eastern Himalaya and have revealed that upper part of Behali Reserve Forest (BRF)  have become degraded due to deforestation and e encroachment of the Arunachali people.

There is a lack of comprehensive studies that integrate socio-economic data with ecological assessments to understand the full impact of urbanization on Sikkim's environment and communities. Few studies provide long-term analyses of urbanization trends and their cumulative environmental impacts in Sikkim Himalaya, which are essential for sustainable planning. While policy recommendations exist, there is limited research evaluating the effectiveness of implemented land use and urbanization policies in Sikkim Himalaya. The interplay between urbanization-induced land use changes and climate change effects in Sikkim Himalaya remains underexplored, necessitating focused research in this area.

Sikkim Himalaya as a part of the Eastern Himalayas (EH), India is one of the 36 global biodiversity hotspots (Pullaiah, 2024).  The EH region is also regarded as a part of crisis ecoregions (Hoekstra et al., 2005). Ever since, its merger with the Indian Union in 1975 the Sikkim state has experienced rapid socio-economic transformation. The forests clearing was extensive, practice of cattle grazing in reserve forests depleted the vegetation cover and most of the khas (village forests) was without trees and eroded (Karan, 1987). The scope for industrialisation increased in Sikkim especially after 2007 as Sikkim was incorporated into North East Council and due to the enactment of New Industrial Policy, 2006 by the Government of Sikkim. This transformation has been characterized by shifts in land use patterns, including the expansion of settlements, infrastructure development, agricultural intensification, and changes in forest cover. In recent decades, rapid urbanization, industrialization and population growth have led to profound land use changes, raising concerns about ecological integrity, biodiversity conservation, and socio-economic sustainability in Sikkim Himalaya. While several studies have examined land use changes in the region mainly at the watershed level (Rai and Sharma 1995; Sharma et al., 2007; Mishra et al., 2020; Mishra et al., 2021; Parida et al., 2022; Behera et al., 2022; Roy et al., 2024), there remains a need for comprehensive analyses that capture the spatial and temporal trends, drivers, and impacts of these changes over the past two decades. Such analyses can provide valuable insights into the underlying processes driving land use change, identify vulnerable areas, and inform evidence-based policy interventions to promote ecosystem resilience and sustainable land use practices. Therefore, the current study aims to investigate the patterns and drivers of land use change in Sikkim over the recent last two decades (2000-2020) using RS and GIS techniques. Specifically, the objectives of this study are:

1. To analyze the spatial and temporal dynamics of land use changes in Sikkim during the last two decades (2000-2020).

2. To provide recommendations for sustainable land use planning and management to promote socio-economic and environmental resilience in Sikkim

By addressing these objectives, this study seeks to contribute to the existing body of knowledge on land use change dynamics in Sikkim and provide valuable insights to policymakers, land managers and researchers to support informed decision-making and sustainable development initiatives in the region.

A. Study Area

Sikkim, a part of eastern Himalayas, India is griddled between 27°04'46" and 28°07'48" North latitude and 88' 58" and 88°55'25" East longitude with a total geographical area of 7,096 sq. km with four districts East Sikkim, West Sikkim, North Sikkim and South Sikkim.  The third highest mountain peak Khangchendzonga forms a major part of Sikkim. The Teesta Khangse glacier & Chho Lhamo in North Sikkim and Mt. Kabru in the southern Kangchendzonga region are the main sources of water, which flows through river Teesta and Rangit respectively. The state of Sikkim is bounded by Nepal in the west, parts of Bhutan and Tibetan Autonomous Region (China) in the East, West Bengal in the South and the Tibetan Plateau of the Tibetan Autonomous Region (China), in the North. It extends 114 km from north to south and nearly 64 km from east to west with the altitude ranging from 300 m to 8598 m. The state is inhabited by a number of ethnic groups including its aboriginal people, the Lepchas, Bhutias and Nepalese. The people of Sikkim have been engaged in different economic activities like tourism, forest related jobs, horticulture, floriculture, mining, power units, pharmaceuticals and other industries besides the government jobs.

Fig. 1.  Location of study area in India and urban towns in East District.

B. Methodology

We collected data from secondary sources, including the GLAD Global Land Cover and Land Use Change dataset, which quantifies changes in forest extent and height, cropland, built-up areas, surface water, and perennial snow and ice from 2000 to 2020 at a 30-meter spatial resolution (Potapov et al., 2022). The datasets contain wide range of data under extensive number of parameters and for very large area. As the area under study was restricted to state of Sikkim therefore the data was clipped for Sikkim only. Further to evaluate the variations within the state, the data was further clipped into four districts i.e., East, West, North and South (Fig. 1). We obtained the full disaggregated data along with legend for the original map and the mapping from the disaggregated classes was downloaded from run through a systematic review process. After completing the primary data extraction and analysis, we conducted an extensive review of published journal articles and books concerning the effects of urbanization on biodiversity in Sikkim. This was complemented by systematic web-based searches. Using "Google Scholar," we specifically searched for literature employing terms such as "urbanization," "impacts," "biodiversity," and "Sikkim." Our review covered publications available up to 2024, and additional searches included technical reports, student theses, government publications, agency reports, and databases of ongoing projects. This literature served to validate our analytical findings and to provide broader context on the implications of land use changes in Sikkim.

The historical background of urbanization in Sikkim, reflects a trajectory influenced by various socio-political and economic factors. Prior to its merger with India, Sikkim was a kingdom ruled by the Chogyal monarchy (Gupta, 1975). Following Sikkim's accession to India in 1975, urbanization gained momentum with the establishment of government institutions, educational facilities, and infrastructure projects. The construction of roads, bridges, and utilities accelerated urban growth, attracting migrants from neighboring states and countries. 

Over the past two decades, substantial shifts in land use and vegetation cover have been observed across various regions, reflecting both anthropogenic influences and environmental processes. The data under study captured a comprehensive assessment of land cover transformations in Sikkim for the year 2000 and 2020 (Fig. 2, Table 1).

Fig. 2. Land Use Changes in Sikkim between (A) 2000 and (B) 2020.

Table 1: Land Use and Land Cover Changes in Sikkim for 2000 and 2020.

B. Vegetation Cover Changes

The structure and development of vegetation in a region is affected by both the anthropogenic and environmental factors (Sharma et al., 2010). Over the span of two decades from 2000 to 2020, the dynamics of vegetation cover have undergone notable shifts across the diverse landscapes of the East, South, North, West and Sikkim regions. A primary focus lies on the alterations observed in dense short vegetation cover, defined as areas with over 79% vegetation cover, which serves as a crucial indicator of ecosystem health and vitality (Styers et al., 2010). The data reveals intriguing trends in dense short vegetation cover, showcasing both gains and losses in different regions. For instance, between 2000 and 2020, the East region experienced a reduction from 13,149.64 hectares to 12,068.67 hectares, indicating a decline in dense vegetation cover (Fig. 2). Similarly, in the North region, there was a decrease from 16,761.73 hectares to 15,540.43 hectares over the same period, reflecting a diminishing extent of dense short vegetation. Conversely, certain regions witnessed a contrasting trajectory. Notably, in Sikkim there was a marginal increase from 107,376.26 hectares to 103,993.66 hectares, suggesting a modest expansion of dense vegetation cover despite potential anthropogenic pressures. Studies show that vegetation changes in response to factors like land use, climate change, and disturbance regimes (Atherden and Hal 1999; Chen et al., 2024). For instance, vegetation alterations due to land use changes can lead to shifts in plant communities and a decrease in species diversity (Erich et al., 2002; Tan et al., 2024). Moreover, vegetation cover plays a key role in controlling erosion rates, with areas of high vegetation density exhibiting lower erosion rates, emphasizing the protective role of vegetation against soil erosion in mountain environments (Sun et al., 2021; Ashraf and Ahmad 2024). Therefore, decrease in short dense vegetation can disrupt ecosystem dynamics, biodiversity, and erosion control mechanisms in mountainous regions. Moreover, alongside the assessment of dense short vegetation, it is imperative to delve into the intricacies of tree cover density, which comprises varying height categories ranging from 3-15 meters, 16-25 meters, to greater than 25 meters. 

Though there is an increase in the area under tree cover of 16-25 meters however across the height categories, discernible trends emerge, elucidating the nuances of tree cover density changes. In particular, the data indicates fluctuations in tree cover density across different height categories, with notable variations observed between 2000 and 2020. For instance, there was a significantly higher decrease in tree cover density for trees ranging between 3-15 meters in East, West and South districts as compared to the decrease in density of taller trees (>25 meters). It is important to emphasise that large trees are much more important for the forest ecosystems than the smaller trees. Large trees play a decisive role in forest ecosystems due to their disproportionate contribution to aboveground carbon storage (David et al., 2023; Romero et al., 2024). They regulate forest diversity, structure, function and aboveground biomass, especially in early successional forests, influencing the total vegetation's biomass significantly (Melinda et al., 2022; Lee et al., 2022; Ralhan et al., 2024). Such insights underscore the multifaceted nature of vegetation dynamics and its intricate interplay with factors such as land use changes, climate variability, and anthropogenic pressures. By juxtaposing these trends with other parameters such as water bodies, snow/ice cover, and land use patterns, a holistic understanding of landscape transformations emerges, offering invaluable insights for ecosystem management and biodiversity conservation efforts.

Although comprehensive biodiversity studies have not yet been conducted in Sikkim, a significant number of species have been recorded in its forest areas and wetlands (SBFP, 2012). The significant decrease observed in tree cover, particularly in the categories of "Tree cover 3-15m trees" and "Tree cover >25m trees," between 2000 and 2020, raises several pertinent questions regarding the underlying drivers and implications of such changes. Firstly, the decline in tree cover within the 3-15 meter height category suggests potential disturbances or alterations in forest ecosystems. This range often represents younger or secondary growth forests, which are susceptible to changes in land use such as deforestation, agricultural expansion, or urbanization. The reduction in this category may signify the habitat loss for various species, disruption of ecological processes, and a decline in biodiversity. Land-use modifications have been shown to increase understorey species composition, affecting the overall functioning and stability of ecosystem (Sandra et al., 2006; Tonleu et al., 2024). Additionally, the enlargement of woodlands due to factors like fire suppression can lead to the establishment of invasive pathogens, impacting the inoculum load and disease prevalence in certain tree species within the forest ecosystem (Singh and Chaturvedi 2017). Invasive Alien Species Titebati (Artemesia milagirica) and Banmara (Eupatorium adenophorum) have spread uncontrollably in different parts of Sikkim (SoER, 2016). During the last decade, forest fire has emerged as a potential environmental threat (Sharma et al., 2014; Dahal, 2024). In Sikkim, studies have shown that forest fires are predominantly ground fires, which significantly damage the biodiversity of the forests (Sharma and Thapa 2021; Dahal, 2024; Singh and Singha  2024). Forest cover in Sikkim has shown no significant improvement since 2011 and natural hazards have had a significantly negative impact on Sikkim’s verdant forests and the Hindu Kush Himalayan region (Banerjee et al., 2019; Adhikari et al., 2024). 

Despite the ecological significance, Sikkim Himalaya faces numerous threats to biodiversity. Increase in population, infrastructure development, urbanization, and climate change, unplanned and mass tourism, loss of rich traditional knowledge (Chettri and Lama 2014; SoER; 2016; Pandey and Priya 2021; Chandra et al., 2024) are among the key threats to biodiversity in the region. The construction of the mega four-lane road in Sikkim has had profound negative impacts on local flora and fauna (Banerjee et al., 2019). Furthermore, the ongoing Sevok-Rangpo railway project (45 kms approx), linking West Bengal and Sikkim will fragment the forests habitat and change the  vegetation  structure and composition along this Sevok-Rangpo route.  The implications of these decreases in tree cover are far-reaching and multifaceted. The hill ecosystem is always under the transition due to the change in frequency, density, abundance, structure and composition of vegetation along forest to urban gradient due to land use change accelerated by various developmental activities including tourism. Previous vegetation studies conducted along a Deorali-Gangtok Ridge in East Sikkim showed high frequency, rich density and abundance of Alnus nepalensis, Saurauia napaulensis, Prunus cerasoides, Schima wallichi, Macaranga pustulata etc (Sharma et al., 2010). However, with the establishment of tourist resorts and urbanization, there has been change in the structure, composition, density, abundance of forest cover during from the last decade along this gradient. With the prospering of tourism industry and rapid urbanization, the changed in structure, composition, density, abundance of vegetation has occurred at rapid pace in Sikkim Himalaya. Ecologically, the loss of tree cover threatens the stability and functioning of ecosystems, leading to altered hydrological cycles, soil erosion, and reduced carbon storage capacity (Kumar et al., 2022). Moreover, the decline in habitat availability can exacerbate biodiversity loss, contributing to species extinctions (Sandor et al., 2022; Premlata et al., 2024) and disrupting trophic cascades. Socioeconomically, the degradation of forest ecosystems can impact local communities dependent on forest resources for livelihoods (Oldekop et al., 2020; Mae et al., 2024), as well as affect global climate regulation (Tian et al., 2022;  Rabbi & Kovács 2024) and resilience to natural disasters (Kumar et al., 2022; Xu, 2024). Addressing the drivers behind the decrease in tree cover requires comprehensive strategies that prioritize sustainable land management practices, conservation efforts, and policy interventions (Pandit et al., 2020). This includes promoting reforestation and afforestation initiatives, implementing effective land-use planning and zoning regulations, incentivizing sustainable forestry practices, and raising awareness about the importance of preserving forest ecosystems for present and future generations. In essence, the drastic decrease in tree cover, particularly in critical height categories, underscores the urgent need for rigorous action to reduce further loss and maintain the invaluable ecological, social, and economic benefits and ecosystem services provided by forests.

B. Land Use Changes

The analysis of land use changes between 2000 and 2020 reveals notable shifts in cropland areas and built-up (urbanized) areas across the North, South, East, and West districts. These changes have multifaceted implications for agricultural practices, urban development, and habitat fragmentation, reflecting the complicated interaction between anthropogenic activities and natural landscapes. The analysis of built-up areas unveils significant transformations in urban landscapes across the districts. Notably, the South district witnessed a substantial increase from 5776.84 hectares to 7897.43 hectares, indicative of infrastructure development due to rapid urbanization (Table 1). Similarly, the West district exhibited a notable increase in built-up areas, reflecting urban sprawl and population growth trends. The west district has the major towns including the state capital Gangtok. Conversely, the North and East districts displayed relatively modest changes in built-up areas, suggesting varying degrees of urbanization pressures and land use planning policies. However, it is essential to note that even incremental changes in built-up areas can have profound implications for land cover, ecosystem services, and habitat fragmentation. In Sikkim, majority of the population subsists in the urban areas of East district (80 %) followed by South district (13%) followed by west (4%) and North (3%) (Paul et al., 2016). The population of Gangtok has surged in recent decades (Rai  and Singh 2022), fuelled by in-migration and tourism (Chakraborty and Ghosal 2024). This influx of people has led to the increase of built-up areas, the proliferation of informal settlements, and the intensification of land-use activities. The impacts of population growth and migration on urban expansion in Gangtok are multifaceted. On one hand, they contribute to economic dynamism, cultural diversity, and social vibrancy, enhancing the city's livability and attractiveness. On the other hand, they exert pressure on natural resources, strain infrastructure systems, and exacerbate environmental degradation.

In addition to Gangtok, other towns of Sikkim Namchi - the capital town of South Sikkim has also transformed rapidly due to urbanization (McDui and Chettri 2018). Likewise, Chungthang - in North Sikkim has also been on the path to urbanization due to state induced development (Chettri, 2017). Similarly, other towns of Sikkim for instance, Jorethang, Rangpo, Singtam, Rhenock, Rongli, Mangan, Pakyong etc are also have taken rapid strides in urbanization. The urban town of Gangtok reflects the impact of urbanization on the environment as urban development has led to changes such as alterations in land use, slope modification, and fragmentation of natural habitats, thereby modifying the habitat's character and introducing man-made habitats (Das et al., 2013; Kumar et al., 2024). During the decade of 1991 and 2001, the population growth rate of this town was only 17.30 % which increased to 1,00,286 in 2011 from 29,354 in 2001 which was around 241 % increase (Paul et al., 2016). Post-2011, Gangtok has witnessed a noticeable suburban sprawl, with rapid expansion of built-up areas beyond the traditional city limits into surrounding rural and semi-urban zones such as Burtuk, Bojoghari, Pangthang, Tadong, Ranipool, and 5th Mile. The trends and patterns of urbanization in Sikkim Himalaya, particularly in Gangtok, are characterized by rapid population growth, spatial expansion, and vertical development (Kumar, 2017).  A shift from vertical growth within Gangtok to horizontal expansion outside city boundaries reflects the limited carrying capacity of the urban core, driving sprawl into previously undisturbed slopes contributing to strain on infrastructure, waste management systems, and local ecosystems in the adjoining areas. 

The observed shifts in built-up areas have far-reaching implications for urban development and habitat fragmentation (Dai et al., 2018; Mansingh et al., 2025). The proliferation of built-up areas can fragment natural habitats, disrupting ecological connectivity and species migration patterns (Jaeger et al., 2016; Wang et al., 2020; Ding et al., 2024). This fragmentation poses challenges for biodiversity conservation, as it isolates populations, reduces genetic diversity, and increases the vulnerability of ecosystems to environmental stressors (Liu et al., 2019; Faye et al., 2024). Correlating these land use changes with other parameters such as tree cover dynamics reveals complex relationships between human activities and ecosystem integrity (Yang, 2021). For instance, the expansion of built-up areas often correlates with declines in tree cover, highlighting the trade-offs between green spaces and urban development (Han et al., 2022; He et al., 2023). Such correlations underscore the need for integrated land use planning approaches that balance economic development with environmental conservation objectives. The analysis of land use changes underscores the dynamic nature of human-environment interactions and the imperative of sustainable land management practices. 

Plate 1: Some of the plates of urban, suburban, rural and riverine ecosystem in Sikkim with urbanization at various stages (A: 17.06.2012; B: 11.12.2016; C: 10.11.2015 D: 13.06.2015).

C. Water Bodies and Snow/Ice Cover

The pristine mountain landscapes of Sikkim, nestled in the Himalayas, have long been characterized by their shimmering snow-capped peaks and glistening glaciers (Starkel and Sarkar 2014). However, the data spanning from 2000 to 2020 of present study paints a concerning picture of dwindling snow and ice cover in this ecologically fragile region. Over this two-decade period, a noticeable reduction in snow/ice cover across Sikkim's mountainous terrain was observed. In 2000, the snow/ice cover in Sikkim's mountains stood at 89,431.38 ha. By 2020, this figure had diminished to 83,482.31ha, reflecting a substantial reduction over the study period. Such a decline in snow and ice cover raises significant concerns regarding the implications for aquatic ecosystems, regional climates, and hydrological cycles (Stewart, 2009; Huss et al., 2017). The implications of this decrease in snow/ice cover are manifold and far-reaching. Aquatic ecosystems, including rivers and streams fed by snowmelt, are particularly vulnerable to alterations in freshwater input (Slemmons et al., 2013; Yan et al., 2021; Leathers et al., 2024). The decline in snow cover can disrupt river flows, exacerbate water scarcity during dry seasons, and heighten the risk of water-related conflicts and socio-economic challenges (Beniston and Stoffel 2014). Reduced snow accumulation alters surface albedo, or reflectivity, leading to increase in absorption of solar radiation and localized warming effects (Skiles et al., 2018). 

The snow cover in North Sikkim, a region renowned for its rugged terrain and high-altitude landscapes (Basnett et al., 2012), has witnessed significant fluctuations over the past two decades. In 2000, the snow cover in North Sikkim encompassed approximately 82061.04 Hectare. However, by 2020, this figure had experienced a noticeable decline, diminishing to 76424.71 Hectares (Table 1). This decrease in snow cover highlights the vulnerability of North Sikkim's mountain ecosystems to changing climatic conditions and underscores the challenges posed by climate change in high-altitude regions (Krishna, 2005; Notarnicola, 2022). The implications of reduced snow cover in North Sikkim are multifaceted and far-reaching (Bawa and Ingty 2012). Moreover, the loss of snow cover in North Sikkim's mountains has implications for regional climates and weather patterns. Snow acts as an insulating blanket, regulating surface temperatures and influencing local microclimates (Roberts et al., 2017). Reduced snow accumulation can exacerbate warming trends, leading to changes in precipitation patterns, cloud cover and atmospheric circulation in North Sikkim and surrounding areas. The rapid melting of snow and ice, along with heavy rainfall, has led to the formation and expansion of moraine-dammed lakes. This has caused glacial lake outburst floods (GLOFs) in the Teesta River in North Sikkim, altering the landscape in many areas of the upper reaches of Sikkim (Dahal et al., 2024).

D. Ecological and Biodiversity Implications

The period from 2000 to 2020 has witnessed profound land cover changes, with significant implications for biodiversity conservation and ecosystem functioning. These changes, including habitat loss, fragmentation, and alterations in ecosystem services, pose considerable challenges to maintaining biodiversity hotspots and key ecological processes (Hasan et al., 2020). The data from table 1 reveals shifts in land cover, such as the reduction in dense short vegetation cover (>79% vegetation) in certain regions. For instance, the East district experienced a decline from 13,149.64 square kilometers to 12,068.67 square kilometers. This loss of dense vegetation indicates habitat degradation and potential fragmentation, which can exacerbate the vulnerability of species and contribute to biodiversity decline (Zambrano et al., 2019; Liu et al., 2019; Tulloch et al., 2016; Faye et al., 2024; Alshayeb, 2025). In addition, , the decrease in tree cover density results in the fragmentation of habitats and the loss of essential wildlife corridors (Laurance, 2004; Theobald  et al., 2011; Hendling et al., 2023). Changes in land cover, including the increase of built-up areas and croplands, can disrupt the provision of ecosystem services critical for human well-being (Mathewos and Aga 2023; Simeon and Wana 2024). The increase in built-up areas, as seen in the South district from 5776.84 square kilometers to 7897.43 square kilometers, results in habitat loss and degradation, compromising ecosystem functions such as water purification and carbon sequestration (Ekka et al., 2023; Assennato et al., 2022; Simeon  and Wana 2024). Given the significant ecological and biodiversity implications of land cover changes, continuous monitoring and mitigation efforts are essential (Schirpke et al., 2017; Li et al., 2022). By tracking changes in vegetation cover, land use, and species populations, conservationists can identify areas at risk and prioritize conservation actions. Moreover, implementing mitigation measures such as habitat restoration, reforestation, and sustainable land management practices can help mitigate the adverse effects of habitat loss and fragmentation, promoting ecosystem resilience and biodiversity conservation.

Biodiversity is essential for sustaining health of ecosystem and achieving Sustainable Development Goals (SDGs) (Lu et al., 2020; Reyers et al., 2020; Saleh et al., 2024). On the contrary, urbanization leads to changes in species composition, diversity and community structure and is a major driver of the rapid decline and extinction of many native species due to habitat loss and degradation (Boivin et al., 2016; Li et al., 2022; Hessen, 2024). Understanding the dynamics of urbanization is crucial for addressing its impacts on the environment and ensuring sustainable development (Bai et al., 2017; James, 2024). Anthropogenic disturbances are generally harmful to species richness, population structure, and the regeneration of tree species. However, moderate disturbances can sometimes benefit the regeneration of certain selected species (Gautam et al., 2016). While numerous studies have explored how urbanization affects ecological patterns and processes, there is still limited understanding of the spatial and temporal distribution of biodiversity (Chen, 2007; Seto et al., 2012; Sun et al., 2022; Ruas et al., 2024). Our understanding of the relationships between urbanization and biodiversity remains inadequate, particularly in the Global South (Batty, 2008; Güeneralp and Seto 2013; McDonald et al., 2020; Sun et al., 2022). As the total urban area is expected to more than double by 2050, understanding the impact of urbanization on species communities becomes increasingly crucial for biodiversity conservation (Zhou et al., 2019; Sidemo et al., 2022). 

Sustainable Land Use Planning and Management in Sikkim: Promoting Socio-Economic and Environmental Resilience

In order to ensure long-term socio-economic, environmental resilience and sustainable land management in Sikkim, a comprehensive and integrated approach to land use planning is essential (Table 2).

Table 2: Strategy and Mechanism for ensure sustainable land management in Sikkim.

Source: Compiled by authors, 2024

With the creation of two more districts in Sikkim (Soreng and Pakyong) few yrs ago (2021), the pace of urbanization and land use change is going to impact biodiversity, ecosystem services in Sikkim. Therefore, future research on Land Use Land Cover (LULC) changes in the Sikkim Himalaya should focus on high-resolution and real-time monitoring, integrating climate change variables to better understand environmental transformations. Predictive modeling tools can help simulate future scenarios, while assessments of biodiversity, ecosystem services, and socio-economic impacts will support holistic planning. There's a need to examine disaster risks linked to land degradation and evaluate existing governance frameworks for adaptive and inclusive management. Community-based monitoring and participatory GIS can enhance local engagement and data accuracy. Additionally, focused research on the impacts of infrastructure and tourism development in Sikkim can offer valuable insights for sustainable land use planning and policy-making.

Santosh Sharma and Sachin Kumar (2025). Land Use changes and the Impact of Urbanization During Recent Decades in Sikkim, Eastern Himalaya, India. Biological Forum, 17(4): 65-78.