Understory diversity and floristic differentiation of Kashmir Himalayan coniferous forests: implications for conservation

The temperate Kashmir Himalaya, regardless of its simple representation as a giant temperate forest, exhibits remarkable vegetation dissimilarity being inadequately perceived. We explored the species diversity and taxonomic composition of herbaceous stratum in 147 plots over 36.75 ha of temperate Kashmir Himalayan landscape, describing three heterogeneous forest types, viz., low-level blue pine (BP), mixed-conifer (MC), and subalpine (SA) forests. Regression and constrained ordination (canonical correspondence analysis) analyses are used to quantify the relevance of environmental variables in governing herbaceous species composition and diversity. Landscape-level richness of 245 species ranging from 113 species in BP forest to 173 species in SA forest is documented. Mixed conifer forest manifested maximal species richness and Whittaker-beta score among the forest types. With an aggregate of 42 species, Asteraceae attributed the optimum species richness accompanied by Poaceae (19 spp.), Lamiaceae (16 spp.), and so on, besides 22 monotypic families. Fragaria nubicola proclaims the dominant species, while Trifolium pratens, Pimpinella diversifolia and Impatiens brachycentra represent the most significant indicator species in BP, MC and SA forests. The consequence of elevation gradient on species richness across the landscape proclaims a significant unimodal paradigm (p = 0.005) ascribed to environmental stress at both elevational extremes. Latitude and precipitation proved as influencing ecological gradients underpinning the distribution of species composition in BP forest. However, in MC and SA forests, geographic location and precipitation and elevation and precipitation are highly associated with CCA-1 axis. To optimize biodiversity protection, conservation efforts must take forest scale variations in flora into consideration.