Disturbance intensity plays an important role in influencing the structural and functional dynamics of ecosystems. The present study was undertaken in the tropical dry deciduous forests of Central India under varying disturbance intensities to understand their influence on structure, diversity and compositional attributes. In total, 242 rectangular plots of 0.5 ha each (50 m × 100 m) were laid in each 8 km2 grid for phytosociological analyses and assessment of disturbance factors and levels. The plots were categorized into four types based on the level of disturbance intensity: 0–20 % {undisturbed forest (UDF)}, 21–40 % {least disturbed forest (LDF)}, 41–60 % {moderately disturbed forest (MDF)} and >60 % {highly disturbed forest (HDF)}. Among the 242 plots, 48, 56, 72 and 66 plots come under UDF, LDF, MDF and HDF categories respectively. The predominant disturbance factors in HDF were fire and fuelwood collection, whereas in the case of MDF, grazing and cut stems were dominant. A total of 202 species (120 genera, 45 families) of adult trees (≥10 diameter at breast height (DBH)) were recorded across the disturbance intensity gradient, with highest species richness in UDF (175 species) and the lowest in HDF (145 species). A significant variation in the stand structure, species composition, richness and tree diversity (Shannon (H′) and Simpson (D) index) has been found across the disturbance intensity gradients. The plots with the highest disturbance intensity (HDF) had the significantly lowest tree density (p < 0.001), basal area (p < 0.001), species richness (p < 0.001), and tree diversity: H′ (p < 0.01), D (p < 0.01) than UDF, LDF and MDF intensity gradients. The diameter-class distribution showed high percentage of small-sized (11–30 cm) trees in UDF (68 %) and LDF (60 %), whereas the medium-sized trees (31–60 cm) were high in MDF (48 %) and HDF (53 %) respectively. The current findings highlight the profound impact of varying disturbance intensities on stand structure, composition and diversity, emphasizing an urgent need for restoration, protection, conservation, and sustainable management for long-term ecosystem services.

Tropical forests, known for their biodiversity and carbon (C) richness, face significant threats from biological invasions that disrupt structural and functional processes. Lantana camara (Family: Verbenaceae) is an invasive shrub that has spread across several Indian landscapes. The present study aimed to assess the changes in tree species richness and total ecosystem carbon (TEC) storage in Lantana camara-invaded (LI) and uninvaded (UI) sites in the tropical dry deciduous forests of Madhya Pradesh, India. Significantly lower species richness (SR), C storage of juveniles, total trees, and total biomass C were observed in LI sites than in UI sites. However, significantly higher C storage of shrubs + herbs (understorey), litter, and soil organic carbon (SOC) were found in LI sites than in UI sites. The percent allocation of C in tree juveniles, adults, understorey, detritus, and SOC to the TEC pool was 2.6, 39.1, 1.4, 5.5, and 51.3 in LI sites and 3.8, 49.7, 0.2, 4.0 and 42.3 in UI sites, respectively. The C stocks of tree juveniles, adults, and herbs were lower by 23.3, 15.7 and 20.3%, respectively, in LI sites than in UI sites, whereas shrub, detritus, and SOC stocks were higher by 95.1, 9.1 and 7.9%, respectively, in LI sites than in UI sites. A significant negative relationship was observed between L. camara density and SR, tree juvenile C, herb C, understorey C, and total ecosystem C storage, while the same had a significant positive relationship with shrub C, litter C, and SOC. The present findings revealed that the plant diversity and total C pools were altered by shrub invasion and have important implications for their quantification in these tropical forests.

Aim: We used an eco-phylogenetic approach to investigate the diversity and assembly patterns of tropical dry forests (TDFs) in Central India. We aimed at informing conservation and restoration practices in these anthropogenically disturbed forests by identifying potential habitats of conservation significance and elements of regional biodiversity most vulnerable to human impact and climate change. Location: Tropical dry forests of Madhya Pradesh, Central India. Methods: We analysed the species richness, stem density, basal area and phylogenetic structure (standardized effect size of MNTD, MPD, PD and community evolutionary distinctiveness cED) of 117 tree species assemblages distributed across a ~230 to ~940 m elevational gradient. We examined how these community measures and taxonomic (Sørensen) and phylogenetic (UniFrac) beta diversity varied with elevation, precipitation, temperature and climatic stress. Results: Species richness, phylogenetic diversity, stem density and basal area were positively correlated with elevation, with high-elevation plots exhibiting cooler temperatures, higher precipitation and lower stress. High-elevation assemblages also trended towards greater phylogenetic dispersion, which diminished at lower elevations and in drier, more stressful plots. Phylogenetic turnover was observed across the elevation gradient, and species evolutionary distinctiveness increased at lower elevations and under harsher abiotic conditions. Main Conclusions: Harsher abiotic conditions at low elevations may act as a selective filter on plant lineages, leading to phylogenetically clustered low-diversity assemblages. These assemblages contained more evolutionarily distinct species that may contribute disproportionately to biodiversity. Conversely, milder abiotic conditions at high elevations may serve as refuges for drought-sensitive species, resulting in more diverse assemblages. Conservation practices that prioritize both high- and low-elevation habitats could promote the persistence of evolutionarily distinct species and areas of high biodiversity within the Central Indian landscape. Establishing connectivity between these habitats may provide a range of climatic conditions for species to retreat to or persist within as climates change.

Rising global atmospheric carbon dioxide (CO2) concentrations has been a major driver of global climate change. In response, several parties to the Paris Agreement have pledged to achieve “carbon neutrality” where CO2 emissions are balanced by various CO2 removal activities. Sequestration of atmospheric CO2 by trees and locking it in different pools (live biomass, detritus, wood products and soil) is widely seen as an easy, cost-effective strategy that would lead to carbon neutrality. Together with attractive carbon incentives, this strategy has led to the mushrooming of several tree plantation projects all over the world. The carbon sequestration potential of a plantation depends upon several factors like species planted, site history, climate, and management practices. While well-planned tree plantations would enable the harvesting of environmental and socioeconomic benefits, ill-conceived tree planting initiatives may turn into an environmental disaster. Prior risk assessments and adoption of an integrated approach in tree plantations would help in reducing the uncertainties and achieving the desired targets. Diversified climate action plans which also include tree plantation as an integral component are necessary to achieve carbon neutrality and climate change mitigation goals.

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers.

Lantana camara (hereafter Lantana) is a highly noxious invasive weed species of global concern. However, its impacts on floristic and soil properties in tropical dry deciduous forests are elusive and fragmented. We aimed to assess the changes in the flora and soil properties following the invasion by Lantana in Central Indian forest ecosystems. Three study sites were selected, and each site was further divided into two subsites: Lantana-invaded (LI) and uninvaded (UI). In total, 60 plots of 0.25 ha each (10 plots in each subsite) were laid randomly. Within each plot, floristic structure, composition, diversity, soil organic carbon (SOC), soil total nitrogen (STN), moisture (M%), pH, and bulk density (BD) were assessed. Lantana-invaded sites showed a significant decrease in density (D), basal area (BA), species richness (SR), and evenness (E) of saplings (<3 cm diameter at breast height [DBH]), juveniles (between 3 and 9.9 cm DBH), and herbs. In LI sites, a reduction of 57% and 25% was observed in lower DBH class of trees (saplings and juveniles). In all the LI sites, significant increase in SOC, STN, and M%, and a significant decrease in pH were recorded. Lantana may greatly impact the vegetation and soil properties, and successively, these strong changes may increase its invasive potential and ability to replace native species by averting their natural regeneration potential. Therefore, a proper management strategy of this noxious weed is imperative to prevent its further expansion and future problems.

Sacred groves (SGs) play an important role in the conservation of local biodiversity and provide numerous ecosystem services worldwide. We studied how the ecological status of Central Indian SGs contributes to regional tree diversity and carbon (C) storage. We inventoried the trees in fifty-nine SGs of Madhya Pradesh and recorded a total of 109 tree species (90 genera, 40 families). The most species-rich families were Fabaceae, Combretaceae, Malvaceae, and Moraceae. The tree density ranged from 75 to 925 individuals ha−1 (mean: 398 ± 32 individuals ha−1), while basal area varied from 2.5 to 69.2 m2 ha−1 (mean: 24.2 ± 1.9 m2 ha−1). The total C stock {tree C + soil organic C (SOC; 0–30 cm)} ranged from 44.7 to 455.4 Mg C ha−1 (mean: 153.8 ± 9.6 Mg C ha−1) across the SGs. The studied SGs represented 74.7% of the total tree diversity and contained 33.1% higher total C stock than the forests of the state. Tree C stock was significantly positively correlated with tree basal area, distance from the nearest village, and number of years of existence. The present study highlights the crucial role of SGs in sustaining regional biodiversity and storing C in biomass and soil. Continued conservation efforts and contained interventions by people are necessary in order to maintain the current role of these SGs as biodiversity and carbon reservoirs of Central India.

Diversity, stand structure and regeneration potential are the key elements of any forest ecosystem. For the present study, seven sites were selected with the aims of assessing plant diversity, structure and regeneration potential in tropical forests across Kanyakumari Wildlife Sanctuary (KWLS), Western Ghats, India. The sites were classified based on the similarity: tropical dry deciduous sites (TDDs I and II), tropical semi-evergreen sites (TSEs I and II) and tropical evergreen sites (TEFs I-III). The phytosociological survey was done by laying a total of 70 plots (10 plots in each study site). Standard methods were followed for the assessment of diversity, structure and regeneration patterns. A total of 267 species (205 genera, 70 families) were recorded. The tree species richness ranged 24 (TDD II) - 76 (TEF III). Of the vegetation spectrum, trees, vines and understorey accounted 56.5, 15.3 and 28.2% respectively to the total flora documented. A total of 66 species were endemic. The total tree density and tree basal area (seedlings, saplings, juveniles and adults) were 18,790 individuals (mean 2684) and 137.6 m2 (mean 19.7 m2) in 70 plots respectively. The mean tree adult density and basal area ranged 370 (TDD I) - 900 (TEF I) individuals/ha and 24.2 (TDD I) - 75.3 (TEF III) m2/ha respectively. The overall species richness was highest in TDD I, but TEF III had the highest tree species richness. The diameter class-wise distribution showed the characteristic 'reverse J-shaped' curve. Most tree species were 'newly recruited'. The dominant species had 'fair' to 'good' regeneration potential. However, 12 tree species showed 'no' regeneration. The overall regeneration pattern of trees was 'good', but 'no' or 'poor' regeneration patterns in some tree species, especially endemics is a point of concern. Since a majority of tree species were 'new recruits', species composition may likely change in the future. The results obtained would help in understanding diversity patterns, structural attributes and regeneration potential in tropical forests of protected areas for better forest management and conservation.

The rapid alteration in the global climate due to anthropogenic activities has profound eco-biological impacts, which invariably affect the ability of natural communities to effectively perform ecosystem services. The eco-biological impacts could be viewed across various dimensions including loss of biodiversity as well as ecosystem goods and services, changes in phenology, prevalence of droughts and forest fires, disease outbreaks, reduced crop yields and increase in intensity and frequency of extreme weather events. Although, the natural ecosystems are innately endowed with the ability to maintain homeostasis by means of resistance and resilience, this ability to cope up is severely impacted by various other factors like deforestation, habitat fragmentation, land-use change and biological invasion, which exacerbate the effects of climate change. The eco-biological impacts of climate change are tied with socio-economic aspects by means of market values of the produce, poverty, undernourishment, livelihood security, etc. At this crucial juncture, forest biomes offer an immense ecosystem service towards climate change mitigation through carbon sequestration. Nevertheless, the three major forest biomes, viz. tropical, temperate and boreal, with their unique characteristics, vary in their response to climate change as well as mitigation potential and response. This review chapter aims to understand the varied climate change impacts and the crucial roles of major forest biomes in climate change mitigation and their various ecological services to formulate better forest management strategies.

Tropical forests are rich in biodiversity with great potential for carbon (C) storage. We estimated ecosystem-level C stock using data from 70 forest plots in three major forest types: tropical dry deciduous (TDD I and TDD II), tropical semi-evergreen (TSE I and TSE II) and tropical evergreen forests (TEF I, TEF II and TEF III) of Kanyakumari Wildlife Sanctuary, Western Ghats, India. The average C stock in these forests was 336.8 Mg C/ha, of which 231.3, 3.0, 2.4, 15.2 and 84.9 Mg C/ha were stored in woody vegetation, understorey, litter, deadwood and soil respectively. The live vegetation, detritus and soil contributed 65.5%, 5.5% and 29% respectively to the total ecosystem-level C stock and distributed in forest types in the order: TEF III > TEF II > TEF I > TSE I > TDD II > TSE II > TDD I. The plant diversity, structural attributes and environmental factors showed significant positive correlations with C stocks and accounted for 6.7, 77.2 and 16% of variance. These findings indicate that the tropical forests in the Western Ghats store large amount of C, and resulting data are invaluable for planning and monitoring forest conservation and management programs to enhance C storage in tropical forests.

Tropical forests are the richest biodiversity hotspots and are under immense natural and anthropogenic pressures that lead to biodiversity loss. One such cause is alien plant invasion that alters the native forest stand structure and composition and disrupts the vital ecosystem functions. Central India, which mainly spans across the three states, viz. Madhya Pradesh, Chhattisgarh and some parts of Maharashtra, is well-known for its sprawling tropical deciduous forests, which are also no less immune to the present-day pressures, including the plant invasion. Alien invasive plants arrive via several pathways and possess unique traits that help them to surpass the barriers in the new habitats, where many influentialfactors might operate upon them. Once established, they may profoundly impact the invaded ecosystem. Most of the studies from Central India have been focused on floristics, forest structure, impact of disturbances, etc., and relatively few studies have addressed plant invasion. Overall, there are 179 invasive taxa in Central India, mostly from the Asteraceae (17.3%) and Fabaceae (14.5%) families. Majority of them are from Tropical America (52%), and most are herbs (69%). An outline of the most common top ten Central Indian invaders has been presented. Climate change might influence invasive plants, and constant monitoring and modelling is required to understand invasive species dynamics for effective management. Invasive alien species are to be tended with extreme caution and smart and novel approaches of putting them to use might help in better management for controlling them. This review will also provide a conceptual basis for improving our general understanding on invasive species and their impact on tropical forest ecosystems.

Sequestration of atmospheric carbon-dioxide in biospheric carbon (C) pools is a key strategy towards climate change mitigation. Soil is a huge C reservoir and its storage potential varies greatly with forest types. Therefore, in the present study, the soil organic carbon (SOC) storage pattern was assessed from 70 plots laid at three selected forest types comprising seven study sites at Kanyakumari Wildlife Sanctuary, Western Ghats, India: tropical dry deciduous (TDD I and TDD II), tropical semi-evergreen (TSE I and TSE II) and tropical evergreen forest (TEF I, TEF II and TEF III) at three depths (0–10, 10.1–20 and 20.1–30 cm). Statistical analyses were performed to understand the relationships between SOC stocks with other predictor variables. The SOC stock varied markedly with forest type and site-wise. The SOC ranged from 58 (TEF III) to 123.6 (TDD I) Mg C/ha with a mean of 84.9 ± 4.4 Mg C/ha at 0–30 cm depth. SOC stock decreased, while soil bulk density increased with increase in soil depth. The TDD forest type (115.6 Mg C/ha) stocked the highest SOC compared to TEF (75.1 Mg C/ha) and TSE (68.9 Mg C/ha) forest types. Of the total SOC stock (0–30 cm), 44.2, 32.0 and 23.8% were stored in 0–10, 10.1–20 and 20.1–30 cm respectively in all the forest types. In contrast, litter C stock were high in TEF and TSE forest types and low in TDD forest type. SOC showed significant (P < 0.01) negative relationships with bulk density, litter C, and vegetation attributes. The SOC stock stored in the study sites amount to 212.9 (TEF III) to 453.6 (TDD I) Mg of CO2 equivalents. The present study reveals that forest type and site characteristics have a profound impact on SOC stock, which would, in turn, exert a great bearing on the ecosystem C cycling. These results would also enhance our ability to evaluate the role of these forest types in soil C sequestration and for developing and validating SOC models for tropical forest ecosystems.

Sacred groves are small or large patches of forest and are rich in biodiversity, store carbon (C) in biomass and soil, besides providing important ecosystem services. However, the information on tree species diversity, biomass, and C storage in sacred groves of Central India, Madhya Pradesh is elusive and fragmented. In the present study, 41 sacred groves were inventoried for tree species diversity, biomass, and C storage in vegetation and soil. A total of 103 tree species from 81 genera belonging to 37 families were recorded. Shannon’s diversity, Dominance, Fisher’s alpha, and species evenness indices for trees varied: 0.77–2.53, 0.07–0.64, 1.58–20.37, and 0.28–0.90 respectively. Tree density ranged 75–675 no. of stems ha−1 with a mean of 271 no. of stems ha−1, while basal area ranged 6.8–47 m2 ha−1 with a mean value of 27 m2 ha−1. Tree biomass ranged 34.9–409.8 Mg ha−1 with a mean value of 194.01 Mg ha−1, while, tree C ranged between 17.5 and 204.9 Mg C ha−1 with a mean value of 97.0 Mg C ha−1. The total soil organic carbon stock (0–30 cm) ranged from 22.4 to 112.5 Mg C ha−1 with the mean value of 62 Mg C ha−1. Biomass C and SOC contributed 61% and 39% of the total C stocks, respectively. Tree C stock showed a significant positive relationship with tree basal area (R2 = 0.968). A total of five tree species belonging to four families were found to be vulnerable in Central India. The present study reveals that the sacred groves of Central India are species rich, have higher C stocks and sequestration potential in both vegetation and soil, and calls for an immediate attention for conservation and planning for long-term C sequestration.

Plant community structure of two tropical deciduous forest sites (I and II which are in different locations with different terrain characteristics viz., elevation and slope pattern) in Kanyakumari Wildlife Sanctuary, Western Ghats were assessed using standard phytosociological methods. Ten plots of 20 m x 20 m each were laid for woody species enumeration and 40 quadrats of 1 m x 1 m (4 in each plot) for understorey vegetation (herbs and plant species that are < 1 m in height) in each site. Overall, 76 plant species were recorded from 41 families, of which 23 contribute to understory. Site I (62) was twice as speciose as site II (31). Greater diversity index of adult woody vegetation was observed in site I (2.30) than site II (2.01). The woody individuals (diameter at breast height, DBH ≥ 10 cm) were more abundant in site I (518 individuals ha-1) than site II (448 individuals ha-1). The basal area of adult trees in sites I and II are 34.7 m2 ha-1 and 30.8 m2 ha-1 respectively. Euphorbiaceae was the most speciose family in both the sites. Twenty-five families in site I and seventeen families in site II were represented by singletons. Diameter classwise distribution of adult trees showed a typical ‘reverse J-shaped’ curve indicating good regeneration status. Concerning understory, site I (19 species) has a greater diversity than site II (six species). The observed differences in the vegetation patterns between the two deciduous forest sites are possibly due to variations in elevation, terrain features and edaphic characteristics.

Carbon inventory was done on two savannah ecosystems (sites I & II) of Kanyakumari Wildlife Sanctuary, Western Ghats, India. Ten plots of 20 m × 20 m each were laid in each site to study woody vegetation and a total of forty quadrats (4 in each plot) of 1 m × 1 m were laid in each site for the understorey. Both sites showed remarkable variations in biomass and carbon accumulation patterns. Site I (213 Mg C/ha) had higher woody biomass carbon than site II (185.9 Mg C/ha). However, the latter had greater understorey biomass carbon (site I – 3.2 Mg C/ha; site II –20.7 Mg C/ha). Overall, the total vegetation carbon accounted to 216.2 Mg C/ha in site I and 206.6 Mg C/ha in site II. On the other hand, soil carbon was higher in site II (183.5 Mg C/ha) than site I (172.3 Mg C/ha). Soil bulk density increased with increase in soil depth in both sites. Cumulatively, even though both sites had almost equal carbon stocks, they show considerable variation in the amount of carbon stocked in their carbon pools. Woody biomass was the largest carbon pool, followed by soil and understorey biomass. The observed variations could be due to differences in terrain characteristics, edaphic factors, incidence of fires, etc. The study emphasizes the important role of savannahs in stocking considerable amounts of carbon in their different carbon pools.

Forest biomass pools are the major reservoirs of atmospheric carbon in both coniferous and broad-leaved forest ecosystems and thus play an important role in regulating the regional and global carbon cycle. In this study, we measured the biomass of trees, understorey, and detritus in temperate (coniferous and broad-leaved) forests of Kashmir Himalaya. Total ecosystem dry biomass averaged 234.2 t/ha (ranging from 99.5 to 305.2 t/ha) across all the forest stands, of which 223 t/ha (91.9–283.2 t/ha) were stored in above- and below-ground biomass of trees, 1.3 t/ha (0.18–3.3 t/ha) in understorey vegetation (shrubs and herbaceous), and 9.9 t/ha (4.8–20.9 t/ha) in detritus (including standing and fallen dead trees, and forest floor litter). Among all the forests, the highest tree, understorey, and detritus biomass were observed in mid-altitude Abies pindrow and Pinus wallichiana coniferous forests, whereas the lowest were observed in high-altitude Betula utilis broad-leaved forests. Basal area has showed significant positive relationship with biomass (R2 = 0.84–0.97, P < 0.001) and density (R2 = 0.49–0.87). The present study will improve our understanding of distribution of biomass (trees, understorey, and detritus) in coniferous and broad-leaved forests and can be used in forest management activities to enhance C sequestration.