Changing landscape configuration demands ecological planning: Retrospect and prospect for megaherbivores of North Bengal

The Gorumara National Park (GNP) is an important conservation area located in the northern region of West Bengal State, India, as it provides habitat for three megaherbivores: Indian One-horned rhinoceros (Rhinoceros unicornis), Asian elephants (Elephas maximus) and Gaurs (Bos gaurus). It harbours one of the last population of the one-horned rhino. In the present study, landscape change and configuration were investigated by comparing three Landsat images, from 1998, 2008 and 2018. The images were classified into six different landcover classes following standard methodology. The present study also involves evaluation of landscape and anthropogenic predictors influence on the megaherbivores of GNP, followed by future landcover simulation for the year 2028. The result shows a significant decrease in the grassland cover from 18.87 km2 to 8.27 km2 from 1998 to 2018, whereas the woodland cover has increased from 50.14 km2 to 62.09 km2 between 1998 and 2018. The landscape configuration indices such as Number of Patches (NP), Patch Density (PD), Interspersion and Juxtaposition (IJI), Aggregation Index (AI) and Mean Shape Index (SHAPE AM) indicated that the landscapes has lost complexity in the spatial placement of patches of different Land Use and Land Cover (LULC) classes. Also, the landscape over the three decades has become uniform in terms of diversity of patches, because of earlier plantation activities by the forest managers. Result also indicated that grassland, along with its class metrics are the top predictors contributing 43.6% in explaining the spatial distribution of megaherbivores in GNP. Results from the simulated landcover of 2028 suggest a possible decline in overall grassland by 6.23% and a subsequent upsurge in woodland by 6.09% from 2018. The present result will be useful in guiding the forest management in developing habitat improvement strategies for the long- term viability of megaherbivore populations of rhino, gaur and elephant in the GNP.

Gorumara国家公园（Gorumara National Park, GNP）是印度西孟加拉邦北部的重要保护区域，作为印度独角犀（Indian One-horned rhinoceros, Rhinoceros unicornis）、亚洲象（Asian elephants, Elephas maximus）与印度野牛（Gaurs, Bos gaurus）三种大型植食动物的栖息地，具有极高的保护价值。该区域是现存为数不多的独角犀种群栖息地之一。
本研究通过对比1998年、2008年与2018年的三景Landsat影像（Landsat），对该区域的景观变化与景观格局展开了调查。研究按照标准方法将影像划分为6类不同的土地覆被（landcover）类型。
此外，本研究还评估了景观因子与人为预测因子对GNP内大型植食动物的影响，并对2028年的土地覆被情况进行了未来模拟。
研究结果显示：1998年至2018年间，草地覆被面积从18.87 km²显著缩减至8.27 km²；而同期林地覆被面积则从50.14 km²增长至62.09 km²。
景观格局指数方面，斑块数量（Number of Patches, NP）、斑块密度（Patch Density, PD）、散布与并列指数（Interspersion and Juxtaposition, IJI）、聚集度指数（Aggregation Index, AI）以及平均形状指数（Mean Shape Index, SHAPE AM）均表明，不同土地利用与土地覆被（Land Use and Land Cover, LULC）类型的斑块空间分布复杂性有所降低。
同时，近三十年来，受森林管理者此前开展的造林活动影响，该区域景观斑块的多样性趋于同质化。
研究结果还表明，草地及其类别指数是解释GNP内大型植食动物空间分布的首要预测因子，贡献率达43.6%。
2028年的模拟土地覆被结果显示，相较于2018年，整体草地面积或将下降6.23%，而林地面积则将相应增长6.09%。
本研究结果可为森林管理工作提供科学指导，助力制定栖息地改善策略，以保障GNP内独角犀、印度野牛及亚洲象等大型植食动物种群的长期存续。