Dry Evergreen Research Articles

Changes in breeding activity of Southeast Asian songbirds in response to the severity of the dry season

Droughts are expected to become more frequent and severe as the climate changes. Tropical songbirds likely reduce reproductive output during extreme droughts such as El Niño events in Southeast Asia as a tradeoff for reducing mortality risks. However, the timing of these rainfall responses and the extent of these reproductive costs are largely unknown in this region. Here we quantified how the amount and frequency of rainfall impacted nest initiation (first egg dates), and how the amount of rainfall may impact the duration of nesting in a given season (last expected fledging date). We tested these hypotheses on seven species of understory passerines in a secondary dry evergreen forest in northeastern Thailand. Using ten years of data (2014–2023) we examined the relationship between rainfall examining both total amounts occurring at key parts of the year (such as just prior to the breeding season) as well the number of “no-rain” days (rainfall gap) on (1) first egg dates and the (2) last expected fledging date of a given season. More severe dry seasons (longer time gaps in rainfall) caused longer delays in the start of egg laying and gap days tended to have a stronger effect than total rainfall. Lower breeding season rainfall resulted in later fledge dates for four species; lower rainfall amounts during the dry season resulted in later fledge dates for three species. There was no relationship between first egg dates and last expected fledging dates for any target species. Overall, it appears that droughts are likely shortening the breeding seasons of many tropical forest birds, but the reproductive costs are still difficult to estimate precisely. Further investigation is also recommended as to how rainfall is affecting nesting success particularly whether greater rainfall is regularly associated with earlier end of season fledging dates.

Correlation between Woody Species and Environmental Variables in a Tropical Forest in Central Laos

The tropical forest biome serves as a significant focal point for conservation endeavors. However, understanding the variations in woody plant composition and the underlying driving factors remains limited. The vegetation gradient within Phou Khao Khouay (PKK) National Park in central Laos presents an intriguing environmental model for investigating these patterns. This study, conducted within PKK National Park, aims to classify woody plant communities of three different forest types: mixed deciduous forest (MDF), dry evergreen forest (DEF), and mixed coniferous forest (MCF), utilizing both the phytosociology approach and multivariate analysis. Data from 32 permanent plots (each measuring 50 m × 50 m) were analyzed, revealing 5,477 tree individuals with a diameter at breast height (DBH) ≥ 5 cm, representing 194 woody species from 64 families and 133 genera. The results indicate significant diversity at the family and genus levels, identifying four distinct plant communities and 44 indicator species based on Tichy and Chytry's phi coefficient method. Stability characterizes the MCF forest type, while the stands of DEF and MDF exhibit differentiation into three communities each. Notably, high heterogeneity in species composition and environmental conditions is evident, with elevation and soil nutrient levels (specifically total phosphorus and total potassium) emerging as primary influencers on species coexistence. The study also highlights correlations between woody plant species composition and topographic and soil variables. These findings underscore the importance of identifying microhabitats conducive to growing and conserving woody plant species within PKK National Park for future research and conservation efforts.

Diversity of Butterflies in Guindy National Park-Butterfly Garden in Guindy Children’s Park

Guindy National Park is the only protected forest oasis holding good tropical dry evergreen forest vegetation sheltering many wild Fauna, and flora amidst the city. The literature survey provides a limited information analysis earlier before, on various aspects of Ecology & Conservation Management, Habitat analysis & assessment, distribution of Vegetation, diversity of fauna like Black buck, spotted deer, Birds, Jackal including lower vertebrates & Butterflies. Butterflies are the sensitive insects which react quickly to any kind of disturbances like changes in the habitat quality and environmental variation. Apart from pollinators they play a major key role in food chain, being prey for birds, reptiles, spiders and predatory insects. Many species of butterflies are strictly seasonal in their occurrence and prefer a particular set of habitats and host plants for their survival. Notably these biological indicators are slowly disappearing due to changes in land pattern and habitat as they are closely dependent on plants.

Physicochemical Soil Properties Following Selective Cutting of Large-Diameter Trees in a Lowland Dry Evergreen Forest in Cambodia

Physicochemical Soil Properties Following Selective Cutting of Large-Diameter Trees in a Lowland Dry Evergreen Forest in Cambodia

Transformation of dry dipterocarp to dry evergreen forests alters food webs of web-building spiders and their prey

Anthropogenic habitat modification is a major contributor to global change. While the modification of natural habitats to agroecosystems attracts most of the attention, little is known about the conversion of one natural ecosystem to another. Dry dipterocarp forest is the key dry forest type across Southeast Asia. Moderate fire disturbance is essential for its regeneration, but humans often prevent fire in these forests. Consequently, dry dipterocarps can change to dry evergreen forests through succession. The consequences of this conversion on food webs are unknown. Using the network approach, we compared the food webs of web-building spiders and their prey in the understory between dry dipterocarp (open canopy, uniform understory) and dry evergreen forests (closed canopy, heterogeneous understory) in north-eastern Thailand. Overall, we collected 560 individual web-building spiders belonging to 37 genera. Further, we collected 1139 prey items from spider webs belonging to 16 arthropod orders. The composition of captured prey and the network structure differed between the forest types. Specifically, the web-building spiders were more specialized and their niches overlapped less in dry dipterocarps than in dry evergreens. The differences in food-web structure were driven mostly by trophic groups turnover rather than interaction rewiring. Implications for insect conservation: The transformation of dry dipterocarp to dry evergreen forests from the prevention of fire disturbance may lead to an altered ecological function of web-building spiders in forest understories. As trophic links and their strength are rewired, habitat modification may also lead to changes in nutrient and energy flow in forest understories.

Challenges and a Strategy for Successful Restoration of Dry Evergreen Afromontane Forests of Ethiopia

Challenges and a Strategy for Successful Restoration of Dry Evergreen Afromontane Forests of Ethiopia

Spatial distribution of the ethnomedicinal plant Aglaonema simplex at the Sakaerat Environmental Research Station, Northeastern Thailand

Abstract. O-thong N, Tasen W, Marod D, Thinkampheang S, Phumphuang W. 2024. Spatial distribution of the ethnomedicinal plant Aglaonema simplex at the Sakaerat Environmental Research Station, Northeastern Thailand. Biodiversitas 25: 3043-3050. Aglaonema simplex Blume (Araceae) is an evergreen herbaceous plant used ornamentally and in traditional medicine. Although the usefulness of this plant has been widely studied and reported, its ecology remains poorly understood. In this study, we examined the effects of various environmental factors on the spatial distribution of A. simplex in a Dry Evergreen Forest (DEF) at the Sakaerat Environmental Research Station (SERS) in Northeastern Thailand. All individual plants were counted; their positions were recorded within a 16-ha Forest Dynamics Plot (FDP), and their distribution pattern was analyzed using Ripley's K function. The spatial distribution of A. simplex was determined using a generalized linear model that incorporated plant density and topographic and edaphic variables within the 16-ha study plot. We found a total of 11,232 A. simplex individuals with a density of 702 individuals ha-1, with a clumped distribution pattern. The modeling results showed that the spatial distribution of A. simplex was positively influenced by soil clay content, soil pH, exchangeable magnesium, and adult tree density; it was negatively influenced by sapling density and rocky outcrops. These findings contribute to the broader understanding of the ecological niche of A. simplex. They can be used to design integrated land management approaches that balance ecological conservation with economic development goals.

The Eastern Ghat of India: A review on plant ecological perspectives

The Eastern Ghats, a discontinuous range of mountains spanning Odisha, Andhra Pradesh, Telangana, Tamil Nadu, and Karnataka has a humid tropical monsoon climate with moderate to high temperatures and heavy rainfall. The Eastern Ghats offer a diverse range of flora and fauna, including endemics. The vegetation is classified into various forest types, including moist deciduous, dry deciduous, dry evergreen, evergreen, semi-evergreen, scrub jungles, and savannah. Eastern Ghat reflects the healthy carrying capacity of the ecosystem. The Eastern Ghats boasts a diverse plant community, with over 3200 flowering plant species, largely due to geographic factors, high seasonality, and elevational variations. The Eastern Ghats, a significant biodiversity granary in India, has been the subject of numerous taxonomic and quantitative surveys. The eastern coast of India's eastern forest (Eastern Ghats) is facing a decline in plant diversity due to overexploitation, habitat destruction, and rampant grazing. This has led to species loss and extinction. The forest cover has also decreased due to anthropogenic pressures. However, there is a lack of significant research on plant species population dynamics, soil surveys, soil chemistry, geomorphology, geobotany, pedology, edaphology, and phytochemistry. To address this, modern science and technology approaches, such as geomorphometry and geobotanical studies using Remote Sensing and GIS techniques, are the need of the hour.

Nest site vegetation structure influences nest predators and nesting success of understory birds in a dry evergreen forest in northeastern Thailand

Abstract Nest predation is typically the main cause of nest failure in forest understory birds; thus, identification of primary nest predators is key to understanding nest predation patterns. Furthermore, the responses of predators are likely affected by vegetation structure, but predator responses to micro-scale habitat characteristics are largely unknown, especially in tropical forests. We used a long-term study with one of the largest datasets of its kind to investigate the extent to which micro-habitat structure (5-m radius surrounding a nest) can predict the likelihood of predation and by which predator. In a secondary evergreen forest in northeastern Thailand, 2013–2021, we found 1,016 active nests of 13 species and 24-hour video-monitored 500 of them. We recorded 336 predation events from 16 nest predator species. From this and previous studies at our site, we identified the top 4 predator species/species groups accounting for ~83% of predation events: Macaca leonina (northern pig-tailed macaque, 36% of predation events), cat snakes (Boiga cyanea [green cat snake] and B. siamensis [gray cat snake]; 20%), Lycodon cf. davisonii (Blandford’s bridle snake, 18%), and accipiters (Accipiter trivirgatus [Crested Goshawk] and A. badius [Shikra]; 9%). These 4 predator species differed in their responses to vegetation structure likely reflecting differences in foraging behaviors. Macaque and accipiters, both diurnal and visually oriented, tended to depredate more visible/open nests, but macaque depredated nests surrounded by more trees and short woody stems (<3 m tall) compared to raptors. For snakes, both nocturnal, cat snakes depredated nests with higher numbers of both short woody stems and woody climbers, whereas bridle snake depredated nests with more trees and fewer climbers. As noted previously, nest predator identity is critical to understanding habitat-predation patterns. Our data suggest that nest site vegetation characteristics influence the likelihood of a given species of predator locating a nest and that even small changes in vegetation structure could significantly alter predation patterns.

A taxonomic revision of GarciniasectionGarcinia (Clusiaceae) in Thailand.

GarciniasectionGarcinia (Clusiaceae) is revised for Thailand with three species and one variety, i.e., two native species: G.celebica and G.exigua, and one cultivated species: G.mangostanavar.mangostana. Detailed morphological descriptions, illustrations, and an identification key to the species are presented, along with notes on distributions, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses, and specimens examined. The section is recognized by its terminal inflorescences of simple cymes, or sometimes a solitary flower; flowers with 4 sepals and 4 petals; male flowers often with a pistillode, and stamens united into a single 4-lobed or 4-angled bundle, and with 2-thecous anthers; usually multilocular ovaries and stigmas with distinct or weak lobes and smooth or rough; and fruits with a smooth surface. Three associated synonyms of G.celebica: G.ferrea, G.basacensis, and G.hombroniana, are lectotypified here in a second-step. In Thailand, Garciniacelebica is found in a very wide variety of habitats, at elevations of 0-1,500 m amsl., and is known to be naturally distributed in all floristic regions. G.exigua is found in dry evergreen forest on limestone hills and in littoral dry evergreen forest on limestone hills, at elevations of 50-100 m amsl. in Krabi Province, the peninsular region. G.mangostanavar.mangostana is found only in cultivation. Garciniaexigua has a conservation status of Vulnerable [VU B2ab(iii)] and the other two species have a conservation status of Least Concern [LC]. The fleshy pulp surrounding the seeds of two species, G.celebica and G.mangostanavar.mangostana is edible and has a sweet-sour taste.

Landscape Ecological Structures and Patterns for Green Space Conservation in Forest Monasteries in Northeast Thailand

The green spaces in Wat Pah play an important role in forest conservation in Thailand. This study identified and analyzed the structures and patterns of landscape ecology in Wat Pah Nanachart, Ubon Ratchathani Province, to guide a conceptual framework for green space conservation in forest monasteries. Spatial analysis and modeling using geoinformatics technology were employed to recognize and characterize these landscapes. Information on the green space conservation and management of Wat Pah was also obtained using an in-depth interview and site observation. The results revealed that most of the green space in Wat Pah is forest, characterized by an ecological matrix and a dry evergreen forest. The forest structure can be divided into three canopies, dominated by the Dipterocarpaceae family, which has regenerated into upper and lower canopies. It is an edge matrix and ecological corridor connected to the internal and external green spaces of Wat Pah. It plays an important role in supporting cultural, religious, and aesthetic activities for ordained monks and Buddhists. The spatial landscape model can be divided into three main zones: Thoranisangha, Buddhawas, Sanghawas. Thoranisangha is an open space covered with traditional and artificially planted tree species. It is located in front of the temple and designed for public utilities in the context of managing and conserving the remaining trees. Buddhawas is a semi-open space mostly covered with traditional tree species. It represents Buddhism’s identity and uniqueness and is used for religious ceremonies and dissemination—listening to sermons, meditating, and praying. Meanwhile, Sanghawas is covered with natural forest and contains residences for monks that are designed to be in harmony with the forest ecosystem.

Linkages among forests, food security and livelihoods: A comparative analysis of tropical dry forests and tropical wet evergreen forests in Sri Lanka

Forests are increasingly recognised as an important contributor to food security and nutrition, especially for the poorest people, in various ways. Their roles and impacts including the degree of access to forest-based nutrition to the poorer segments however vary depending on the specific geographic and socio-political contexts and forest types. This study examines the nature of forest dependence for food security and nutrition in two dominant forest types in Sri Lanka, namely dry humid forest and wet evergreen forests. Proportionate to the forest cover area in either forest system, this study enumerated 500 households in the dry forest ecology and 190 households in the wet evergreen forest ecology. The findings provide a first quantitative benchmarking of the nature of forest food collection and modelling of the socio-demographic factors determining the forest food collection in the Sri Lankan context. The results show that food produce collection in terms of quantity and value are significantly higher in the wet evergreen forest system and the factors driving the dependence on forests are tied to agricultural involvement of the households. Other factors such as economic status, education, accessibility of the forest emerge statistically insignificant. On the other hand, in dry humid forests, economic status and access to forest become significant factors. Evidence confirms the location specific nature of forest food connection and make the case for context-relevant interventions to foster forest-food interface.

A Contribution to the Vascular Flora of Vedharanyam and Talaignayar Reserve Forests, Tanjore District, Madras State

The two reserves dealt with in this paper lie between 70°31'-80° E and 10°-11° N on the eastern coast of peninsular India in Tanjore District, Madras State. The two are separated from each other by about 18 kilometers; the Vedharanyam R. F. lying a little south of Talaignayar. The Vedharanyam R. F. has a Tropical Dry Evergreen type of forest, whereas Talaignayar shows characteristic salt-marsh or swamp vegetation. One new species and 3 new records have been noted.Two botanical tours were conducted in August 1960 and January 1961 and altogether 218 taxa were collected. All the specimens have been deposited in the Southern Circle Herbarium of Botanical Survey of India, Coimbatore (MH).

Hysterium madraspatanum (Hysteriaceae), a new species from Tropical Dry Evergreen Forest of Tamil Nadu, India

A new species of Hysterium, is described from tropical dry evergreen forest region of Chennai, Tamil Nadu, India, based on both morphological characteristics and molecular phylogenetic analysis using the Internal Transcribed Spacers (ITS) region of nuclear ribosomal DNA. The key morphological characters of the ascomata include the presence of a longitudinal slit remaining closed even at maturity. The ascospores biseriate having three septa with all the cells evenly pigmented including the terminal cells. The ascus measuring 115–122 × 20–22 μm. Ascospores initially two celled and finally become four celled, hyaline first, later changing to yellow and then dark brown, oblong to ellipsoid, 28–39 × 7–12 μm. The nrITS-based phylogenetic tree inferred from the Bayesian posterior probabilities indicate that H. madraspatanum is closely related to Hysterium pulicare, H. angustatum and H. rhizophorae. However, H. madraspatanum is morphologically distinct from them by having relatively larger spore size, shallow groove in the ascomata, spores with concolorous terminal cells. Therefore, is a novel species under the genus Hysterium. Azadirachta indica is reported in the study as a new host for the genus Hysterium.

Do remnant forest patches provide microclimate buffering? A case study from Sri Lanka

Tropical forests have declined in extent considerably owing to large scale deforestation for providing land for multiple uses, and this has reduced their collective capacity to provide many important ecological functions. In the present study, conducted in the tropical island of Sri Lanka, we focus on remnant patches of two common and co-occurring vegetation types in the dry zone, Dry Mixed Evergreen Forest and Scrub Forest, to test (a) whether small remnant forest patches facilitate microclimate buffering and, if so, (b) whether the two forest types differ in terms of their potential to buffer the microclimate, and (c) whether the extent of canopy cover influences the microclimate buffering capacity. Co-occurring Grasslands were used as reference habitats. We used multiple temperature, relative humidity and vapour pressure deficit related metrics, and showed that Dry mixed Evergreen Forest and Scrub Forest had significant microclimate buffering potential, the latter to a lesser extent than the former (Dry mixed Evergreen Forest > Scrub Forest). These results are noteworthy, given that the patches of both forest types were relatively small (mean ± standard deviation: Dry Mixed Evergreen Forest = 0.63 ± 0.13 km2 and Scrub Forest = 0.10 ± 0.07 km2), intermixed and scattered across the same landscape. The study also showed that, after controlling for effects of patch size, the extent of canopy cover had a significant impact on most of the microclimate metrics. The impact of patch size on microclimate metrics was less pronounced. These findings highlight the need for conserving remnant forest patches, especially of the Dry Mixed Evergreen Forest, as refuges of biodiversity, particularly in the context of tropical forests in developing countries facing severe threats of deforestation.

Variation in water utilization by mammal diversity in Khao Phaeng Ma Non-hunting area, Thailand

Access to suitable water sources is important for mammals. This study aimed to compared mammal diversity and water use among water springs, standard artificial ponds, and water pans within the Khao Phaeng Ma Non-Hunting Area in 2020 and 2021. Two camera traps were installed at each water sources for 749 nights with a total of 12 camera traps of 6 water sources. A total of 19,467 photographs were recorded comprising 13,777 photographs of gaur (Bos gaurus, vulnerable and the most important species in the area), and 5690 photographs of other mammals. In the wet season, relative use was highest at standard artificial pond number 2, which is established in the forest plantation area (4 × 4 m spacing, 12–20 m height, and 60%–80 % crown cover) and has a high volume of water, and at water pan number 1, which mimics a natural water spring in the man-made grassland and can supply water to mammals throughout the year. In the dry seasons, relative use was highest at water pan numbers 1 and 2; at the same time, other water sources dried up. During the study period, the number of mammal species was highest at water pan number 1 (10 species, diversity index [H′] = 1.38), and water pan number 2 (11 species, H′ = 1.75). Grazers and browsers, including gaur, sambar deer (Rusa unicolor), northern red muntjac (Muntiacus vaginalis), omnivores (e.g. wild boar, Sus scrofa), and Asian black bear (Ursus thibetanus), used the water pan in the artificial grassland and standard artificial pond in the forest plantation rather than the water spring in the dry evergreen forest. Beside forest types, the use of water springs was associated with water period (months), while the use of standard artificial pond and water pans was associated with water surface area, water depth, altitude, species diversity, and species richness, and number of mammals photographed. The results show that water pans were more suitable for utilization by mammals than are other water sources.

Environmental factors differentially influence species distributions across tree size classes in a dry evergreen forest in Sakaerat Biosphere Reserve, northeastern Thailand

ABSTRACT Plant communities in tropical forests are influenced by multiple environmental variables. For trees, soil and topographic characteristics are key factors that impact the establishment of many species. In this study, the impacts of soil properties and topography on forest structure, species composition, α- and β-diversity, and tree species distribution across size classes were investigated in a dry evergreen forest (DEF) in the Sakaerat Biosphere Reserve, northeastern Thailand. Within a 16 ha permanent plot, all trees with a diameter at breast height (DBH) ≥ 1 cm were recorded. Tree species distributions mostly respected gradients of plot elevation and soil nutrient, including available P; these variables were strongly associated for most size classes. Structural attributes (basal area and tree density) of trees with a DBH of 5–10 cm were highly sensitive to these variables. For trees with a DBH of 2–5 cm, α-diversity was negatively associated with available P while β-diversity was associated with topography and available P. These findings demonstrate the strong influence of topographic and edaphic variables in shaping the DEF. Sensitivity to these variables, particularly elevation and increases in available P, increased with increasing tree size among size classes, as small trees were less sensitive than were larger trees. Our study provides an example of how different environments affect many of the features of tropical forest structure, such as tree size class and species composition.

Use of remote sensing and GIS in assessing the impact of Prosopis juliflora proliferation on land use, land cover and diversity of native flora at Point Calimere Wildlife Sanctuary, India

It is crucial to accurately quantify land use and land cover (LULC) within a protected area to understand the implications of habitat changes on biodiversity. Today’s remote sensing and GIS technologies greatly facilitate analysis of LULC, especially with regards to tracing changes over space and time. This study uses remote sensing and GIS to examine the impact of climate, herbivore, and anthropogenic pressures including invasive Mesquite Prosopis juliflora on native plant communities at Point Calimere Wildlife Sanctuary. Classification of satellite images revealed that dry evergreen, mudflat, and water bodies had transformed into open scrub from 1995 to 2018 and the shift in LULC is detected with optimal accuracy (85%). Changes in LULC are largely attributable to a rise in open scrub caused by the growth in P. juliflora from 3 to 6 km2 since 1995. GLM-based regression to examine the influence of climate, herbivores, and anthropogenic pressure including P. juliflora on native flora show native tree density, shrub density, shrub diversity, herb, and grass cover decreasing with P. juliflora cover or density. These findings imply that as the P. juliflora spreads the native plant diversity and density at Point Calimere Wildlife Sanctuary will continue to decline. P. juliflora is being eradicated in phases through management efforts, however, here we recommend a coordinated effort to curb further expansion in order to reverse ecological decline.

Species composition, relative abundance, and habitat association of birds in Dodola dry evergreen afro-montane forest and sub-afro-alpine scrubland vegetation, southeast Ethiopia.

Birds' functional groups are useful for maintaining fundamental ecological processes, ecosystem services, and economic benefits. Negative consequences of loss of functional groups are substantial. Birds are usually found at a high trophic level in food webs and are relatively sensitive to environmental change. The first surveillance bird study was carried out southeast of Ethiopia adjacent to Bale Mountain National Park aimed at investigating the composition, relative abundance, and distribution of Aves. Using regular systematic point transact sampling, the density and species composition were analyzed through the mark recapture distance sampling engine assisted by R statistical software. This study recorded a total of seventy-eight bird species over two distinct seasons. Among these, fifteen species were exclusive to Erica habitats, twenty-six were found in natural forest habitats, and three were specific to plantation forest habitats. The study also discovered three endemic species. Based on the 2018 IUCN Red List categories, six of the species are globally threatened, three are near threatened, and the remaining sixty-nine are classified as least concern. The relative abundance of birds did not significantly differ across habitats and seasons, but variations were observed among blocks. Bird density was found to fluctuate across the three habitats and two seasons; however, these habitat differences were not influenced by seasonal changes. The findings of this study reveal that the differences in composition and relative abundance are not merely seasonal changes in the forest and Erica habitats. Instead, these habitats create microclimates that cater to specific bird species. However, this localized endemism also presents challenges. The concentration of endemic species and potential resource constraints could pose a threat to these habitat-specialist birds.

Ardisiacrenatasubsp.mukdahanensis, a new subspecies of Primulaceae from Thailand.

A new subspecies, ArdisiacrenataSimssubsp.mukdahanensis Chatan & Promprom (Primulaceae), is described from Mukdahan Province, Thailand. This discovery was made during field studies conducted from 2021 to 2023, during which the authors collected and analysed specimens, comparing them with relevant taxonomic literature and herbarium collections. A.crenatasubsp.mukdahanensis is distinct from its closest relative, A.crenatasubsp.crassinervosa by a combination of morphological traits, such as moderately dense minute hairs on young shoots, abaxial side of young lamina and calyx, peduncles and pedicels; larger flowers (7.0-7.5 mm) that are pure white or pinkish; larger fruits (7-8 mm) and absence of glandular punctation in organs such as lamina, calyx, corolla, anther and fruit. This new subspecies grows in slightly dense dry evergreen forests or open areas near streams and is preliminarily assigned to the Data Deficient (DD) category according to IUCN guidelines.