Tropical Dry Evergreen Forest Research Articles

Two new species of South Asian Cnemaspis Strauch, 1887 (Squamata: Gekkonidae) from the Gingee Hills, Tamil Nadu, India

Abstract We describe two new small-bodied, sympatric species of south Asian Cnemaspis belonging to the mysoriensis + adii clade from the Gingee Hills in Tamil Nadu, peninsular India. The two new species can be easily distinguished from the other eight described members of the mysoriensis + adii clade by their dorsal pholidosis, the configuration of femoral and precloacal pores in males, a number of meristic characters and subtle differences in colouration, beside 6.7–20.8 % uncorrected pairwise ND2 sequence divergence. The two species represent different ecomorphs, one a stouter, microhabitat generalist and the other a more slender, elongate rock specialist. The discovery of two new species from granite boulder habitats and Tropical Dry Evergreen Forests is indicative of the importance of these areas for biodiversity. It is likely that similar rocky habitats across southern peninsular India will harbour many more undescribed species.

Allometric Models to Estimate the Biomass of Tree Seedlings from Dry Evergreen Forest in Thailand

Seedlings are an important stage for plant populations, as the abundance and rigor of seedlings can indicate a changing forest structure in the future. Studying the different traits of the seedling can represent how the plant grows. Biomass is one of the traits that can represent the plant’s performance and many other growth processes of the seedling. Several allometric equations have been developed to estimate tree biomass. However, allometric equations for the biomass of seedlings remains poorly studied, especially those from the tropics. The objective of this research is to create and develop a model that can be used to predict the biomass of seedlings, including total biomass, aboveground biomass, and belowground biomass, from root collar diameter, shoot height, main stem length, and wood density from 205 two-year-old seedlings from twenty tree species found in dry evergreen forest in Huai Kha Khaeng Wildlife Sanctuary, Uthai Thani, Thailand. The results showed that the root collar diameter, shoot height, and wood density could be used to create a model to best predict the seedling biomass. This model should be tested with other seedlings in the wild and other datasets to evaluate the performance of the model. To our knowledge, this study is among the first to provide the first allometry for seedlings in tropical dry evergreen forest. The results from this study will allow ecologists to monitor and examine the growth of the seedlings at all stages of life in dynamic tropical environments in the future.

Distribution and new records of Myxomycetes from Tropical Dry Evergreen Forests of South India

The present survey is a preliminary study of the diversity of Myxomycetes occurring in the tropical dry evergreen forest vegetation of the southeastern coastal belt of India. A total of 11 taxa belonging to the orders Ceratiomyxales, Trichiales, Stemonitidales and Physarales were collected, studied, and described from this region. The identification was supported using both morphological and microscopic characters. Ceratiomyxa fruticulosa var. arbuscula, Arcyria insignis, Arcyria incarnata, Hemitrichia serpula, Stemonitis flavogenita, Physarum notabile, Fuligo septica var. candida, Fuligo septica var. septica, and Comatricha anomala are reported for the first time from Tamil Nadu, South India.

Increasing liana biomass and carbon stocks in tropical dry evergreen forests of southern India

Tropical forests act as a great carbon reservoir covering about 30% of the global carbon content, however, structural alteration of these forests caused by forest disturbances adversely affects the carbon cycle. One such structural change happening in these tropical forests is the increasing dominance of lianas (woody climbers). Among various tropical forest types, lianas are an integral constituent of the tropical dry evergreen forests (TDEFs) found in peninsular India. A re-inventory of lianas was carried out to observe temporal changes in basal area and carbon stock in two 1-ha permanent plots of two disturbed tropical dry evergreen forest sites (TDEF; Oorani -OR and Puthupet - PP) over a 19-year interval (2001-2020). The total basal area in OR and PP increased respectively by 2.26 m2 ha-1 and 0.93 m2 ha-1. The total biomass and the carbon stock in OR and PP increased by 82% and 51% respectively. The dominant species Strychnos lenticellata showed an increase in its basal area by three-fold in OR, whereas, in PP, a marginal increase of 4% was observed. The lower diameter class (1-6 cm) showed an increase in basal area in OR and PP by 101% and 16% respectively. The mid-diameter class (6-11 cm) was the top contributor of the total biomass/carbon in both OR and PP in the latest re-inventory (2020). The present results show that lianas, although known to negatively affect the forest biomass/carbon stock, play an important role in carbon sequestration, thus providing insights into their ecological importance which will certainly be useful in proposing strategies for the conservation of this forest type dominated by lianas.

Temporal changes in tree community structure and carbon stocks in a human-impacted tropical dry evergreen forest, South India

Long-term studies in forest ecosystems are crucial to interpret the dynamics and are essential for conservation and management. However, characterizing long-term dynamics in relation to disturbance across dry tropics is often constrained by a dearth of data particularly from Indian tropics. In this context, a one-hectare permanent plot established in 2001 was revisited in 2011 and further re-censused in 2020 to ascertain species composition, stand structure and carbon stock dynamics of tree community over a 19-year period (2001−2020). Although species richness remained more or less unaffected, tree species composition did vary with the addition and loss of five and 10 species over this period. Species-level mortality rates overshadow the annual recruitment rate resulting in a net decrease in structural components. The results revealed that tree density decreased profoundly to 583 individuals ha−1 in 2020, roughly 46% of the initial inventory. Similarly, basal area is reduced by 40% (from 58.27 m2 ha−1 to 34.91 m2 ha−1), highlighting the impact of increased site disturbance over 19 years. The distribution of individuals and basal area to various diameter classes displayed a reverse J-shaped trend in both the inventories suggesting that all the size classes suffered equally over the years. The total carbon stock was as high as 416.01 Mg ha−1 in the initial inventory and reduced to 250.70 Mg ha−1 in the present re-census. Relative carbon stock calculations revealed that Ficus benghalensis (−46.05 Mg ha−1), Drypetes sepiaria (−22.68 Mg ha−1) and Pterospermum canescens (−14.98 Mg ha−1) represented 64.84% of total carbon stock loss over the period. Among the 29 resourceful species, Memecylon umbellatum, Drypetes sepiaria and Glycosmis mauritiana represented the highly targeted species with varied dietary and medicinal importance. These findings attest the impact of anthropogenic disturbances on species composition and carbon stock potential of the present site, which underline the need for such long-term monitoring efforts useful to forest management and conservation.

Phytochemical, In vitro Anti-inflammatory and Antimicrobial Potential of Hugonia mystax L.

Hugonia mystax L., (Linaceae), is commonly distributed in the thorny scrubs and tropical dry evergreen forests of Tamil Nadu, which has been valued for centuries in traditional system of medicine for the treatment of various ailments. In the present study was an attempt to investigate the phytochemical nature and anti-inflammatory, antimicrobial potential by adopting suitable methods. Phytochemical analysis of Hugonia mystax L., plant extracts revealed the presence of various biochemical compounds such as alkaloids, flavonoids, glycosides, triterpenoids and saponins etc. Since triterpenoids and flavonoids have remarkable anti-inflammatory activity, so our present work aims at evaluating in vitro anti inflammatory activity of Hugonia mystax L., by HRBC membrane stabilization method. The inhibition of hypotonicity induced HRBC membrane lysis was taken as a measure of the anti-inflammatory activity. The percentage of membrane stabilization for ethanolic extracts and Diclofenac sodium were done at different concentrations. The maximum membrane stabilization of Hugonia mystax L., extracts was found to be 94.97 % at a dose of 2000 μg/ml. Therefore, our studies support the isolation and the use of active constituents from Hugonia mystax L., in treating inflammations.

Status of important coastal habitats of North Tamil Nadu: Diversity, current threats and approaches for conservation

Coasts are among the most vulnerable ecosystems to the effects of climate change and the impacts of strong weather events. At the same time, they are also crucial buffers of these phenomena around the world. The current study describes the is ecological and geomorphological uniqueness of North Tamil Nadu’s coast. Five important coastal wetlands were identified in this region, namely Pulicat Lagoon, Adyar Estuary, Kovalam-Muttukadu Backwaters, Odiyur-Mudhaliyarkuppam Lagoon and Kaliveli Lake, which were survyed. The variety of habitats found here include mangroves, backwaters and creeks, estuarine areas, oyster reefs, sandy beaches and sand dunes, seagrass beds, salt marshes, and tropical dry evergreen forests. A total of 913 species from eight animals’ classes were recorded from these hotspots, of which 709 species were recorded during the study. Species recorded as bycatch have also been identified and marked so in the checklist The hotspots were assessed using a detailed criteria matrix. This study also highlights the ecological importance of these wetlands, discusses the current threats to them and explores conservation challenges and approaches from a socio-ecological and legal-policy framework.

Assessment of tree species diversity and above-ground biomass in two disturbed tropical dry evergreen forests of Coromandel coast of India

The tree diversity and carbon stock of all woody plants were investigated in two-hectare square plots (100 m x 100 m) were established in Suryanpet (SP) and Velleripet (VP) which is tropical dry evergreen forest (TDEF) sites on the Coromandel Coast of peninsular India. All trees ? 10 cm girth at breast height measured at 1.3 m from the rooting point were enumerated. A total of 35 tree species (? 10 cm gbh) belonging to 34 genera and 23 families were recorded in tropical dry evergreen forests. Tree species richness in 27 (dominant species Dimorphocalyx glabellus Thw.) and 18 (dominant species Strychnos nux-vomica L.) in SP and VP respectively. A total density of woody plants 671 and 1154 individuals in SP and VP respectively. The basal area of trees in the two study sites SP (40.70 m2 ha-1) and VP (45.46 m2 ha-1). Most abundant families are Loganiaceae, Euphorbiaceae and Rutaceae and its family index value (FIV) is 56.14, 39.12 and 21.40 respectively. The aboveground biomass (AGB) of trees totaled in site SP (405.3 Mg ha-1) and VP (721.3 Mg ha-1). The extent of tree species diversity and estimated carbon stock of the TDEF sites, which provides the baseline data on the floristic structure and diversity of this forest for better management and conservation.

Leaf Traits of Trees in Tropical Dry Evergreen Forests of Peninsular India

A plant functional trait study was conducted to know the existing relationship between important leaf traits namely, specific leaf area (SLA), leaf dry matter content (LDMC), and leaf life span (LL) in tropical dry evergreen forest (TDEFs) of Peninsular India. Widely accepted methodologies were employed to record functional traits. The relationships between SLA and LDMC, LDMC and LL, and SLA and LL were measured. Pearson’s coefficient of correlation showed a significant negative relationship between SLA and LDMC, and SLA and LL, whereas a significant positive relationship was prevailed between LDMC and LL. The mean trait values (SLA, LDMC, and LL) of evergreens varied significantly from deciduous species. SLA had a closer relationship with LDMC than LL. Similarly, LL had a closer relationship with SLA than LDMC. Species with evergreen leaf habits dominated forest sites under study. Evergreen species dominate the study area with a high evergreen-deciduous ratio of 5.34:1. The S strategy score of trees indicated a relatively higher biomass allocation to persistent tissues. TDEFs occur in low elevation, semiarid environment, but with the combination of oligotrophic habitat, high temperature and longer dry season these forests were flourishing as a unique evergreen ecosystem in the drier environment. The relationships found between leaf traits were in concurrence with earlier findings. Trees of TDEFs survive on the poor-nutrient habitat with a low SLA, high LDMC, and LL. This study adds baseline data on key leaf traits to plant functional trait database of India.

First report of the fleshy mushroom Trichaleurina javanica (Rehm) M. Carbone et al. (Ascomycota: Pezizales: Chorioactidaceae) from southern India

Trichaleurina javanica was collected from tropical dry evergreen forests, located in the southeastern coastal belt of India. This is the first report of the species from southern India. Trichaleurina javanica is a fleshy and rubbery cup-like mushroom, brownish-grey in colour with a brilliant yellowish-orange disc. The identification is supported using morphological and microscopical characters. It is one of the less known wild edible mushrooms belonging to Ascomycota.

Greater biodiversity in regenerated native tropical dry evergreen forest compared to non-native Acacia regeneration in Southeastern India

The 20 km-50 km-wide belt of tropical dry evergreen forest inland from the southeastern coastline of India has undergone biodiversity loss due to timber harvest and agriculture in the last 200 years. Reforestation restores ecosystem function and increases population sizes and diversity. Sadhana Forest reforested an area of 28 ha and replenished the water table through intensive soil moisture conservation. Results show rapid growth of planted native species and germination of two species of dormant Acacia seeds. Using standardised inventory methods, we documented 75 bird, eight mammal, 12 reptile, five amphibian, 55 invertebrate species, and 22 invertebrate orders. Bird abundance at point count stations, invertebrate sweep net captures and leaf count detections, and Odonate and Lepidopteran visual detections along fixed-paced transects were significantly greater in areas with native plants. Sadhana Forest's reforestation demonstrates the potential to restore ecosystems and replenish water tables, vital components to reversing ecosystem degradation, and corroborates reforestation efforts in other regions of the world.

Greater biodiversity in regenerated native tropical dry evergreen forest compared to non-native <i>Acacia</i> regeneration in Southeastern India

The 20 km-50 km-wide belt of tropical dry evergreen forest inland from the southeastern coastline of India has undergone biodiversity loss due to timber harvest and agriculture in the last 200 years. Reforestation restores ecosystem function and increases population sizes and diversity. Sadhana Forest reforested an area of 28 ha and replenished the water table through intensive soil moisture conservation. Results show rapid growth of planted native species and germination of two species of dormant Acacia seeds. Using standardised inventory methods, we documented 75 bird, eight mammal, 12 reptile, five amphibian, 55 invertebrate species, and 22 invertebrate orders. Bird abundance at point count stations, invertebrate sweep net captures and leaf count detections, and Odonate and Lepidopteran visual detections along fixed-paced transects were significantly greater in areas with native plants. Sadhana Forest's reforestation demonstrates the potential to restore ecosystems and replenish water tables, vital components to reversing ecosystem degradation, and corroborates reforestation efforts in other regions of the world.

Butterfly diversity of Chennai, Kancheepuram, Chengalpet and Thiruvallur districts in Tamil Nadu, India

A long term butterfly study was conducted from January 2014 to March 2020 at 17 locations with varied habitats namely Tropical Dry Evergreen forests, Grasslands, Scrubland, Wetland and Community park covering four districts namely Chennai, Kancheepuram, Chengalpet and Thiruvallur of Tamil Nadu, India. A total of 128 species from the Chennai district, 114 species from the Chengalpet district, 67 species from Thiruvallur district, and 66 species from Kancheepuram district were recorded. The habitat of Tropical dry Evergreen Forest habitat recorded the highest butterfly number with 118 species. The sighting of the Red-spot Jezebel (Deliasdes combesi) was the most significant record from this study. The butterfly diversity in the month of November was seen to be the highest. We also assessed the relative abundance and species distribution patterns of butterflies in the study area.

Ecosystem-level carbon storage and its links to diversity, structural and environmental drivers in tropical forests of Western Ghats, India

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.

Changes in tree diversity and carbon stock over a decade in two Indian tropical dry evergreen forests

ABSTRACT Repeated and continuous monitoring of changes in a habitat provides a platform to investigate concurrent variation in the structure, species composition, and function of a forest. We assessed tree diversity and carbon stock changes in two Indian tropical dry evergreen forest (TDEF) sites namely Sendhirakillai (SK) and Palvathunnan (PT) after 10-year time scale. Two 1-ha plots were delimited one in each disturbed and undisturbed site in 2007 and re-measurements were undertaken in 2017. Over the sampling period, species richness showed little variation in both the sites. Out of 38 species identified, 26 species decreased in abundance, nine increased, and three remained unchanged. A total of 860 trees were lost from both the sites in 10-year interval. Site PT witnessed maximum loss (44% – 559 stems). Tree species density, basal area, and carbon stocks decreased tremendously in all girth classes at site PT. Total biomass and carbon stocks were decreased by 42% in site PT and conversely, they increased by 9% in site SK. The substantial difference noticed between the two sites highlights the impact of human disturbance and the need for periodical biodiversity assessment through re-census in Indian TDEFs and also in similar global dry tropical forests.

Variation in soil organic carbon stock with forest type in tropical forests of Kanyakumari Wildlife Sanctuary, Western Ghats, India.

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.

Diel activity pattern of meso-carnivores in the suburban tropical dry evergreen forest of the Coromandel Coast, India

Sympatric and similar body-sized species exhibit interspecific competition for resources. The present study investigated diel activity of five meso-carnivore species (Canis aureus, Felis chaus, Paradoxurus hermaphroditus, Viverricula indica, and Herpestes edwardsii) in a human-dominated region of Auroville and around Pondicherry University using camera-trap survey data. Diel activity pattern and overlap were estimated using the kernel density method. The Jungle Cat Felis chaus and the Golden Jackal Canis aureus exhibited cathemeral diel activity with a high overlap between them (Δ̂1 = 0.78). The Indian Grey Mongoose Herpestes edwardsii displayed a diurnal activity pattern and had low overlap with the Small Indian Civet Viverricula indica (Δ̂1 = 0.34). Moderate overlap was found between the Small Indian Civet and the Palm Civet Paradoxurus hermaphroditus (Δ̂1 = 0.32). Therefore, diel activity patterns of mesocarnivores indicate inter- and intra-specific trade-off competition avoidance resulting in successful foraging. The present camera-trap survey has provided insights into diel activity patterns and more attention is required to be paid to the study of feeding and breeding ecology of these species in human-dominated landscapes.

Assessment of liana diversity and carbon stock in differently disturbed tropical dry evergreen forests of southern India

Assessment of liana diversity and carbon stock in differently disturbed tropical dry evergreen forests of southern India

Late Pleistocene and Holocene vegetation changes and anthropogenic impacts in the Cauvery delta plains, southern India

A 5 m long core from Uttarangudi in the distal plain of Cauvery delta in South India provides evidences of vegetation, climate and anthropogenic activities during the late Pleistocene and Holocene. The pollen catchment area for this region is the localised sources, including the adjoining Tertiary upland plateau. The recorded variation in pollen assemblages and sediments indicates that the environmental conditions have changed over time from aerial oxidising to lacustrine or ponded environment. The lack of pollen records from 17,802 cal BP until 11,535 cal BP suggests severe drier conditions and an extremely patchy, species-poor Tropical Dry Evergreen Forest (TDEF) vegetation community associated with an arid climate. Between 11,535 and 8487 cal BP, partial climatic amelioration appears to have occurred, and the trend become humid until 7034 cal BP characterised by the expansion of the TDEF vegetation and strengthening of the monsoon precipitation. The period from 7034–3553 cal yr BP recorded a regressive transition of the forest taxa influenced by a weakened monsoon precipitation and enhanced anthropogenic activity. The subsequent increase of disturbance signals post 3553 cal yr BP is in agreement with independent archaeological evidences obtained from this region.

Endemic plants of tropical dry evergreen forest, Southern India

Abstract During the last two decades of intensive botanical survey of the tropical dry evergreen forest, a total of 82 endemic taxa were found out of 1142 species enumerated from 85 sites in the three Coromandel Coastal districts of the state Tamil Nadu: Cuddalore, Kancheepurm and Villupuram, and in the Pondicherry district. Of 82 species, 17 are trees, 11 shrubs, 9 climbers and 45 herbs. Distribution of these endemic species was analyzed and categorised as endemic to the country, peninsular India, southern India, Eastern and Western Ghats, and at the state and district level. Interestingly, the study found that some endemic species were disjunctly distributed between districts, states, ghats, climatic regimes and bioregions. Anthropogenic disturbance and species threat status were also studied and discussed.