Two dominant biomes that occur across the southern Indian peninsula are dry deciduous "forests" and evergreen forests, with the former occurring in drier regions and the latter in wetter regions, sometimes in close proximity to each other. Here we compare stem and leaf traits of trees from multiple sites across these biomes to show that dry deciduous "forest" species have, on average, lower height: diameter ratios, lower specific leaf areas, higher wood densities and higher relative bark thickness, than evergreen forest species. These traits are diagnostic of these dry deciduous "forests" as open, well-lit, drought-, and fire-prone habitats where trees are conservative in their growth strategies and invest heavily in protective bark tissue. These tree traits together with the occurrence of a C 4 grass-dominated understory, diverse mammalian grazers, and frequent fires indicate that large tracts of dry deciduous "forests" of southern India are more accurately classified as mesic deciduous "savannas."

Aim How seasonal drought influences tree species distributions might shape future vegetation composition with impending changes to rainfall patterns. Theory suggests that across a seasonal drought gradient, dry‐tolerant species might have wider distributions than species sensitive to seasonal drought, which will be restricted to less seasonal conditions. As wet‐associated species drop out with increasing seasonality, the community will contain mainly dry‐tolerant species. Time period Present. Location Western Ghats Biodiversity Hotspot in peninsular India. Major taxa studied Woody angiosperms. Methods Across a 1,200 km seasonal drought gradient, we modelled occurrences of 183 species using Gaussian logistic regression in a hierarchical Bayesian framework. We used the first‐order model coefficients to attribute the association of species to seasonality (dry/wet) and second‐order coefficients to assess modal responses. For 92 species, we checked for an interaction between dry/wet association and two traits: wood density and specific leaf area (SLA). Finally, we assessed the consequences of the seasonality associations of species for regional community assembly. Results Of 183 species, 38% were significantly wet associated, 27% dry associated and 34% indifferent to seasonality. Nearly 80% of species had estimated modes of occurrence within the seasonality range considered here. Species with lower SLA and lower wood density were more likely to occur in more seasonal sites where dry‐associated species formed the majority of co‐occurring species. The proportion of wet‐associated species increased only after intermediate levels of seasonality. The community proportion of extreme wet‐associated species decreased prominently from less to more seasonal sites. Main conclusions Dry‐associated species persisted in less seasonal sites, but not vice versa. A shift toward more seasonal rainfall might favour dry‐associated species and shrink the ranges of wet‐associated species. Future work should assess how the intensity and duration of drought and interactions with other drivers of global change regulate the relative performance of species at more and less seasonal sites.

Adaptation to changing environmental conditions is a driver of plant diversification. Elevational gradients offer a unique opportunity for investigating adaptation to a range of climatic conditions. The use of specialized metabolites as volatile and phenolic compounds is a major adaptation in plants, affecting their reproductive success and survival by attracting pollinators and protecting themselves from herbivores and other stressors. The wormseed Artemisia brevifolia can be found across multiple elevations in the Western Himalayas, a region that is considered a biodiversity hotspot and is highly impacted by climate change. This study aims at understanding the volatile and phenolic compounds produced by A. brevifolia in the high elevation cold deserts of the Western Himalayas with the view to understanding the survival strategies employed by plants under harsh conditions. Across four sampling sites with different elevations, polydimethylsiloxane (PDMS) sampling and subsequent GCMS analyses showed that the total number of volatile compounds in the plant headspace increased with elevation and that this trend was largely driven by an increase in compounds with low volatility, which might improve the plant’s resilience to abiotic stress. HPLC analyses showed no effect of elevation on the total number of phenolic compounds detected in both young and mature leaves. However, the concentration of the majority of phenolic compounds decreased with elevation. As the production of phenolic defense compounds is a costly trait, plants at higher elevations might face a trade-off between energy expenditure and protecting themselves from herbivores. This study can therefore help us understand how plants adjust secondary metabolite production to cope with harsh environments and reveal the climate adaptability of such species in highly threatened regions of our planet such as the Himalayas.