Grasslands half‐full: investigating drivers of spatial heterogeneity in ungulate occurrence in Indian Terai

Abstract

Grassland ecosystems have declined in their extent globally, driving declines in wild ungulate populations. Even within the remnant grasslands, ungulate distribution is highly heterogeneous for reasons that are not well understood. This in turn undermines both local and landscape level conservation efforts for these often‐neglected ecosystems and the herbivores they support. We investigated grassland‐ungulate relationships in the Terai region of North India, where wild ungulates are patchily distributed across alluvial grasslands, a besieged ecosystem. Specifically, we posited that spatial variation in grassland habitat use by swamp deer (Rucervus duvaucelii duvaucelii), hog deer (Axis porcinus) and spotted deer (Axis axis) would be explained by community composition, palatability of key grasses, and fire and flooding regimes in grasslands. Hierarchical clustering and multivariate ordination revealed that three dominant tall‐grass communities and the narrowly distributed and more palatable short grass Cynodon‐Oryza community were only marginally influenced by fire and flood histories. Ungulate habitat use, assessed using occupancy models for spatially correlated data, indicated that hog deer were ubiquitously distributed across the grasslands in the park (habitat use probability, ᴪ = 0.92, se = 0.05) utilizing a diverse range of grassland types, while spotted deer (ᴪ = 0.80, se = 0.17) and swamp deer (ᴪ = 0.45, se = 0.10) occurrence within grasslands was relatively lower. Grass height and grassland extent positively influenced habitat use of swamp deer and spotted deer, respectively. However, grassland community composition, fire history, flood history and palatability were relatively uninformative predictors of fine‐scale habitat use. Our study provides a robust baseline for future monitoring of grasslands and ungulates as well as insights for the design and implementation of grassland management interventions.

Grassland conservation and restoration in India: a governance crisis

“…Besides multiple ecosystem services, grasslands support immense biodiversity and endemism, reflecting their ancient Indian roots. Endemic species like the critically endangered Great Indian Bustard ( Ardeotis nigriceps ), Swamp Grass Babbler ( Prinia cinerascens ), the vulnerable One‐horned rhinoceros ( Rhinoceros unicornis ), and the Swamp deer ( Rucervus duvaucelii ), as well as reptiles like Ophisops lizards, indicate the antiquity of the Indian grassland biomes (Dutta et al 2010; Agarwal & Ramakrishnan 2017; Rastogi et al 2022). Grasslands support the livelihoods and food security of millions of people through agriculture, collection of grass for various purposes, cattle grazing, and sustenance of pastoralism throughout the nation.…”

Influence of resource gradients and habitat edges on density variation in tiger populations in a multi-use landscape

“…The exceptions were grasslands where both short and tall grasses were found, including some areas with extensive livestock grazing. A likely explanation for low herbivore densities in tall grasslands is that palatable grasses for wild ungulates sharply declines within about three months of prescribed winter burning both in PAs and MUFs (Rastogi et al, 2022). We did not find a statistically significant relationship between tiger densities and proximity to edges, with tiger density hotspots both occurring forest edges and within the forest-interior (Appendix S6).…”

Status of Swamp Deer Rucervus duvaucelii duvaucelii (G. Cuvier, 1823) in grassland-wetland habitats in Dudhwa Tiger Reserve, India

“…Swamp Deer are indicator species of the alluvial floodplains (Ahmed 2007;Singh & Prasad 2013). Many wetlands/swamps in the study area are threatened due (Rastogi et al 2022). The results from the study revealed that about 30% of the overall grasslands were used by the species, with an occurrence probability of more than 40%.…”