Data from: Floristic diversity and indicator species analysis along altitudinal gradients of the Upper Indus Basin, northern Pakistan

Understanding how altitudinal gradients influence floristic diversity and
indicator species is essential for unlocking the ecological dynamics of
biodiversity-rich regions. We examined the floristic diversity,
communities’ formation and their respective indicator species across
defined altitudinal zones of the Upper Indus Basin region in Indus
Kohistan Valley, northern Pakistan. Vegetation was sampled along transects
ranging from 1957-3380 m using quadrat, with a total of 600 quadrats from
30 different sites surveyed during the summer season (June-August). Most
plants belonged to family Asteraceae, Pinaceae, Lamiaceae and
Berberidaceae, with chamaephytes as the dominant life forms, followed by
geophyte and Phanerophytes. Cluster Analysis classified the vegetation
into three communities: Taxus-Rumex-Mentha (TRM),
Pinus-Indigofera-Leontice (PIL), and Pinus-Phyllanthus-Valeriana (PPV).
Species attributes plots identified based on Canonical Correspondence
Analysis demonstrated that TRM community is primarily influenced by
calcium, pH and salinity. The PIL community is limited by potassium,
oxygen reduction potential, sand and silt while the PPV community by
sodium, MWHC, soil moisture and carbon content. Tukey showed that the TRM
community had the highest mean dominance, the PIL community exhibited the
highest Simpson, Shannon and Evenness indices, and the PPV community had
the lowest values, indicating that soil properties and microclimatic
factors along the altitudinal gradients shape the species composition and
association. Detrended correspondence analysis explained a total of 23.89%
of the variance, as the first axis illustrated the maximum gradient length
(3.07) further strengthen the influence of environmental variables on
species distribution and association. The DCA indicated that
environmnental variables such as salinity, pH, carbon content, soil
texture, and calcium substantially influenced species distribution and
association, a pattern supported by the Mantel test. It is recommended
that reforestation efforts should prioritize the PPV community at
high-altitudes zone (2390–3380 m) and consider sodium, MWHC, Soil moisture
and carbon content when selecting suitable indicator species for
restoration.