Tropical Semi-evergreen Forest Research Articles

Structural diversity and carbon stocks in a tropical semi-evergreen forest in Bangladesh

Tropical forests are well-known as highly productive terrestrial ecosystems, which contribute significantly to the global carbon (C) cycle. Studies indicate a correlation between the structural diversity of forests and carbon stocks in the overall forest carbon stocks, and this relationship varies across tropical ecosystems. Understanding this connection is crucial to preventing the transfer of threats to unprotected areas when safeguarding specific forests. The present study was conducted in the undisturbed natural forests of Rema Kalenga Wildlife Sanctuary, Habigonj, Bangladesh. The study aimed to estimate C stocks within the soil-vegetation system of this forest ecosystem and elucidate relationships with stand structural diversity, focusing on vertical stratification and spatial association of tree species. Stand-level C stock models, constructed through tree-level carbon stocks using allometric equations, were based on stand variables such as basal area and mean or dominant tree height. Results identified five canopy strata, with strata two and three accounting for 60% of C stocks. The importance value index of tree species demonstrated a significant association with the C stocks contribution of tree species. The total ecosystem carbon stock ranged from 185 to 220 Mg ha−1, with aboveground 103 to 132 Mg ha−1, belowground 21 to 26 Mg ha−1, litter 2.4 to 4.4 Mg ha−1, dead wood 0.5 to 4.9 Mg ha−1 and soil 11 to 44 Mg ha−1. Species diversity indices exhibited weaker relationships with C stocks, while Pielou's evenness index demonstrated a strong negative relationship (P < 0.05) to C stocks. This comprehensive assessment provides insights into the C dynamics of the forest ecosystem. It offers valuable information for policymakers devising climate change mitigation strategies through the conservation management of tropical forests as crucial C sinks.

New Suctobelbidae (Acari, Oribatida) from Mexico

ABSTRACT Two new suctobelbid mite species (Oribatida, Suctobelbidae), Suctobelbella (Flagrosuctobelba) crassisetosa sp. nov. and Suctobelbila tetrasetosa sp. nov. are described based on adults collected from leaf litter in secondary semi-evergreen tropical forest in Mexico. Suctobelbella (F.) crassisetosa sp. nov. is similar to S. (F.) muronokiensis and S. (F.) plumosa in having thick notogastral setae and numerous lateral teeth on the rostrum, but differs from both by the number of genital setae, and the morphology and length of some notogastral setae. Suctobelbila tetrasetosa sp. nov. is similar to S-bila dentata in having one pair of notogastral tubercles, three pairs of simple lateral teeth on the rostrum and short notogastral setae, but differs from the later by the number of genital setae and the presence of long notogastral cristae.

New faunistic and taxonomic data on oribatid mites (Acari: Oribatida) of Mexico

This study is based on oribatid mite materials collected from leaf litter in secondary semi-evergreen tropical forests in Mexico; 85 species from 64 genera and 37 families are found; of these, 15 species are recorded for the first time in Mexico, and three species are recorded for the first time in the Neotropical region. A new species of the genus Mucrobates (Scheloribatidae) – Mucrobates solidarensis sp. n. – is described. An identification key to the known representatives of Mucrobates is presented.

New Scheloribates (Topobates) (Acari, Oribatida, Scheloribatidae) from Mexico

The subgenus Scheloribates (Topobates) (Oribatida, Scheloribatidae) is recorded in Mexico for the first time. Two new species of the subgenus—S. (T.) moskovchenkoi sp. nov. and S. (T.) paramoskovchenkoi sp. nov.—are described, based on adults collected from leaf litter from the karst pits in the secondary semi-evergreen tropical forest. Scheloribates (T.) moskovchenkoi is similar to S. (T.) tibetensis in the presence of heterotridactylous legs and long bothridial seta with elongate, lanceolate head having setiform apex, but it differs from the latter by the number of notogastral setae, the different length of notogastral setae, in having sparse small foveolae in dorsoanterior and dorsocentral parts of notogaster, the position of saccule Sa, the presence of tubercle-like process on the trochanter IV, and the absence of translamella. Scheloribates (T.) paramoskovchenkoi is similar to S. (T.) moskovchenkoi in the presence of bothridial seta with elongate, lanceolate head having setiform apex and 13 pairs of notogastral setae, but it differs from the latter in having monodactylous legs and five pairs of notogastral sacculi, strongly reduced pteromorph, the presence of tooth-like process on the trochanter IV, the presence of two longitudinal dorsodistal carinae and concavity between them on the leg tarsi I, II, and in the absence of foveolae on the notogaster and ventrobasal tooth on the leg tibiae I, II.  

Three new species of Oppiidae (Acari, Oribatida) from Mexico.

Three new species of Oppiidae (Oribatida)Graptoppia (Apograptoppia) rooensis sp. nov., Neoamerioppia (Neoamerioppia) mexicoensis sp. nov., and Ramusella (Insculptoppia) quintanaensis sp. nov.are described based on adults collected from leaf litter in a large karst pit in the secondary semi-evergreen tropical forest in Mexico. The subgenus Graptoppia (Apograptoppia) is recorded for the first time in the Neotropical region.

Environmental management: a country-level evaluation of atmospheric particulate matter removal by the forests of India.

Particulate matter (PM) is a critical air pollutant, responsible for an array of ailments leading to premature mortality worldwide. Nature-based solutions for mitigation of PM and especially role of forests in mitigating PM from an ecosystem perspective are less explored. Forests provide a natural pollution abatement strategy by providing a surface area for the deposition of PM. Depending on their structure and composition, forests have varying capacities for PM adsorption, which is again less explored. Hence, in the present study, we evaluate the removal capacity of PM by the forest-type groups of India. Deposition flux and total PM removal across sixteen forest types were estimated based on the 2019 dataset of PM using Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) data. Externality values and PM removal costs by industrial equipment were used for associating an economic value to the air pollution abatement service by forests. The total PM2.5 removal by forests in 2019 was estimated to be 1361.28 tons and PM10 was estimated to be 303,658.27 tons. Deposition of PM was found to be high in littoral and swamp forests, tropical semi-evergreen forests, tropical moist deciduous forests, and sub-tropical pine forests. Tropical dry deciduous forests had the highest net weight % removal of PM with 39% removal for PM2.5 and 39% removal for PM10. The air pollution abatement service by forests for PM removal was 188 M US dollars (USD) with externality-based removal service by forests of 2009 M USD. The net PM removed by all forests of India was estimated to be approximately worth ₹ 470-648 Crore (59-81 million dollars) for PM2.5 and worth ₹56,746-1,22,617 Crore (7093-15,327 million dollars) for PM10 based on valuation using value transfer method. The study concludes that forests can be a significant contributor to PM reduction at a global level. Especially for India's National Clean Air Programme and further research and policy considerations, the findings would be extremely useful.

Contribution to the knowledge of the oribatid mite genus Gymnobodes (Acari, Oribatida, Carabodidae), with description of a new species from Mexico

A new species of Gymnobodes (Oribatida, Carabodidae) – G. paraminimus sp. n. – is described from leaf litter of secondary semi-evergreen tropical forest in Mexico. A revised generic diagnosis, identification key and data on distribution and habitats of representatives of the genus are presented.

Effects of thinning and tree enrichment on carbon stocks and tree species diversity in a secondary semi-evergreen tropical forest in Yucatan Peninsula

Effects of thinning and tree enrichment on carbon stocks and tree species diversity in a secondary semi-evergreen tropical forest in Yucatan Peninsula

New species of Plateremaeoidea (Acari, Oribatida) from Mexico

Two new species of plateremaeoid oribatid mites from the genera Jacotella and Plateremaeus, J. alexandrovskiyi n. sp. and P. sedovi n. sp., are described from leaf litter of secondary semi-evergreen tropical forest in Mexico. The description of J. alexandrovskiyi is based on adult and tritonymphal instars, P. sedovi on adult and larval instars. Identification keys to known species of Jacotella and Plateremaeus are provided.

Common Faunal Diversity on Forest Floor and Their Importance in Forest Ecosystem: Bonai Forest Division, Odisha, India

Bonai Forest Division (BFD) is enjoying the tropical moist deciduous, tropical dry deciduous, and tropical semi-evergreen forest. Among the biotic and abiotic factors, faunal species that are found on the forest floor are very important. They are important members of the forest food chain, feed upon the dead and decaying matter, and after death, add organic matter to the soil as a source of nutrients for the floral communities but there is a lack in documentation. For a better understanding of the role and functions of these faunal species, there is a need for study and documentation. Keeping the importance of faunal species of forest floor, we made an attempt to document common faunal species of BFD, Odisha during June 2021- August 2022. From the study, authors observed 54 common faunal species found on the forest floor. It was noticed that the forest floor of BFD is dominated by class Insecta, Reptilia, and Arachnida which helps to maintain a well-balanced food chain and allows the floral and faunal diversity to flourish.

Fluxes of energy, water and CO2 above a tropical monsoon forest in Dong Nai: results of 10 years of measurements

This paper explores more than 10-year continuous measurements of energy, water and carbon dioxide fluxes on a first-established eddy covariance site in Vietnam above a mature semi-evergreen tropical seasonal forest. Daily, seasonal and interannual variations of turbulent fluxes and meteorological parameters were studied. Evapotranspiration decreased in the second half of a dry season and net ecosystem exchange of CO2 increased to positive values (the tropical forest becomes a source of CO2 instead of a sink) in a hot-dry period of a year (March-May). Net radiation was the parameter with minor interannual and seasonal variation. Precipitation varied significantly from year to year and the variation was great between dry seasons. Variations of precipitation affected the annual rate of evapotranspiration but had no proven effect on the annual net ecosystem exchange of CO2. The ecosystem of tropical forest was the considerable net sink of CO2 from the atmosphere.

Modelling Species Richness and Functional Diversity in Tropical Dry Forests Using Multispectral Remotely Sensed and Topographic Data

Efforts to assess and understand changes in plant diversity and ecosystem functioning focus on the analysis of taxonomic diversity. However, the resilience of ecosystems depends not only on species richness but also on the functions (responses and effects) of species within communities and ecosystems. Therefore, a functional approach is required to estimate functional diversity through functional traits and to model its changes in space and time. This study aims to: (i) assess the accuracy of estimates of species richness and tree functional richness obtained from field data and Sentinel-2 imagery in tropical dry forests of the Yucatan Peninsula; (ii) map and analyze the relationships between these two variables. We calculated species richness and functional richness (from six functional traits) of trees from 87 plots of the National Forest Inventory in a semi-deciduous tropical forest and 107 in a semi-evergreen tropical forest. Species richness and functional richness were mapped using reflectance values, vegetation indices, and texture measurements from Sentinel-2 imagery as explanatory variables. Validation of the models to map these two variables yielded a coefficient of determination (R2) of 0.43 and 0.50, and a mean squared relative error of 25.4% and 48.8%, for tree species richness and functional richness, respectively. For both response variables, the most important explanatory variables were Sentinel-2 texture measurements and spectral bands. Tree species richness and functional richness were positively correlated in both forest types. Bivariate maps showed that 44.9% and 26.5% of the forests studied had high species richness and functional richness values. Our findings highlight the importance of integrating field data and remotely sensed variables for estimating tree species richness and functional richness. In addition, the combination of species richness and functional richness maps presented here is potentially valuable for planning, conservation, and restoration strategies by identifying areas that maximize ecosystem service provisioning, carbon storage, and biodiversity conservation.

Ecological legacies of past fire and human activity in a Panamanian forest

Societal Impact StatementTropical forests provide global ecosystem services and harbor much of Earth's terrestrial biodiversity, but the mechanisms driving the patterns of biodiversity remain uncertain. Palms are one of the most abundant and most widely used plant groups, particularly in the Neotropics. Our data highlight how both direct and indirect human influence that occurred decades to hundreds of years ago can affect the abundances of palm species in modern tropical forests. Our results highlight that biodiversity is dynamic, and changes through time, and that human activities can affect species composition for centuries in tropical forests.Summary Human activities over the past decades and centuries, including fire, cultivation, and forest opening, may have left ecological legacies that persist in modern tropical forests, particularly among palms. We investigated whether past human activities affected modern palm abundances in a well‐studied plot located in a tropical semievergreen forest of Panama. We analyzed soil cores for charcoal to reconstruct past fire events and phytoliths to reconstruct past vegetation changes. We dated as many charcoal fragments as possible to place a temporal framework on past fire events. Our analysis documented widespread fires that occurred 600–900 years ago across the plot. Oenocarpus mapora increased in abundance as a result of these fires, though other palms did not. A subsequent increase in O. mapora occurred later in the relative absence of fire and was likely due to game hunting during the construction of the Panama Canal. Our results showed that the enrichment of O. mapora was determined by disturbance characteristics (e.g., timing, type, and intensity), but the persistence of increased abundances was likely determined by traits (life history characteristics). These data highlight the complexity of human–environment interactions and how they can persist for centuries in settings with long‐lived trees such as tropical forests. These data highlight the importance of adding a historical context to further understand modern ecological patterns and processes.

Tree Diversity and Timber Resources Richness of Reserve Forests under Pasighat Forest Division, Arunachal Pradesh, India

A combined study on the tree diversity and timber resources richness was carried out in five reserve forestsof tropical moist and tropical semi evergreen forests under Pasighat forest division, Arunachal Pradesh.Total tree species richness was 92 and varied from 44 to 55. The total stem density ranged from 282.50 to426.25 individuals per ha and basal area from 18.23 to 58.56 m2 ha-1. The Shannon Index of diversity waslow in all reserves ranging from 1.24 to 1.46. Terminalia myriocarpa is a dominant species in three reserveforests while Gmelina arborea in the other two. Based on the Arunachal Pradesh Gazette notification numberNo. FOR.220/IND/2005/ Royalty/4391-4591 dated 8th March 2018 trees were categorised in one of the 7royalty classes or designated unclassed. The highest number of species was found under B2 category in allreserves. Tree density of timber species ranged from 178.33 to 316.25 individuals ha-1 and basal area from14.10 to 55.72 m2 ha-1. Among different timber classes, tree density and basal area per ha were the highestfor A4 timber class in four reserves contributing 33% to 66.49% in terms of basal area. The species includedin the A4 class are Teminalia myriocarpa, Phoebe goalparensis, Gmelina arborea and Mesua ferrea. The studyexhibits that reserve forests of Pasighat division are rich in terms of tree composition and wealth of timberresources. The study is first of a kind to include both ecological information as well as economic wealth offorest communities that can be applied in forest management and conservation.

Population density and nesting behaviour of Indian Giant Squirrel Ratufa indica (Erxlebeln, 1777) in Bhimashankar Wildlife Sanctuary, Western Ghats of Maharashtra, India

The Indian Giant Squirrel Ratufa indica (Erxlebeln, 1777) has been officially designated as Maharashtra’s state animal. It is restricted to the eco-sensitive Western Ghats region and is currently classified as Least Concern species on the IUCN Red List. However, the species is dependent on intact habitat and is negatively impacted by habitat fragmentation. Population density and nesting behavior were studied in a major habitat in the tropical semi-evergreen and evergreen forest of India’s Bhimashankar Wildlife Sanctuary. Two-hundred-and-twenty-three direct sighting along 60 km line transects were used to estimate squirrel density. It averaged 13.9±0.18 squirrels/km2. Nesting characteristics were evaluated using 4,224 nests. The squirrel uses 52 different tree species for nesting, with Mangifera indica (15.57%), Olea dioica (14.65%), and Mallotus phillippensis (9.78%) being the most popular. The drays were found on trees that are taller than average, have a massive girth at the breast height, and have continuous closed canopies. To avoid predators, Indian Giant Squirrels usually flee to the nearest adjacent tree. 

Glimpse of Herbaceous and Woody Climbers of Hassan District, Karnataka

The study was carried out to document the species of herbaceous and woody climbers in the Western Ghats region of the Hassan district. A total of 170 species of climbers were documented belonging to 126 genera under 46 families. The dominant climber families are Leguminosae (26 spp.), Convolvulaceae (18 spp.), followed by Cucurbitaceae (17 spp.). Of the total climbers documented, 76 species belongs to herbaceous climbers and 94 species belongs to woody climbers. Of the six climbing mechanisms, twiners (54 %) are most predominant, followed by tendril climbers (21 %), stragglers-armed (13 %), stragglers-unarmed (8 %), root climbers (3 %), and hook climbers (1 %). Distribution among the vegetation revealed that a maximum number of species inhabit tropical dry deciduous forest (52 spp.), scrub forest (39 spp.), and wasteland (33 spp.) have the most species, followed by home garden (28 spp.), tropical semi-evergreen forest, (21 spp.), tropical moist deciduous forest (16 spp.), and other vegetation types. The study also documented the various uses of climbers for human consumption (42 spp.), medicinal purpose (98 spp.), ornamental purpose (26 spp.), and other uses (4 spp.).

Plant species diversity in a tropical semi-evergreen forest in Mizoram (northeastern India): assessing the effectiveness of community conservation

Community conservation of forest as a means of biodiversity conservation has gained broad acceptance in recent years. However, there are not many studies in India on how effective they really are for conservation of plants and how they compare to formal protected areas. This study was carried out in Reiek forest, a community conserved forest protected for more than a century, initially by the village Chiefs and after the abolishment of chieftainship, by the community of the nearby villages. An attempt was made to study the plant species diversity of this forest which falls under the Indo-Myanmar diversity hotspot and it was compared to two ecologically similar formal protected areas within Mizoram. A total of 265 species belonging to 213 genera and 89 families were recorded. Two vulnerable species Eleocarpus rogusus and Saraca asocas were identified. It was found that this community conserved forest contained more plant species than the two protected areas. But endemic and threatened species were found to decline in the community conserved forest. 

Variation of fatty oil content in different populations of &lt;em&gt;Mallotus nudiflorus &lt;/em&gt;(L.) Kulju &amp;amp; Welzen occurring in diverse agro climatic zones of Assam

Mallotus nudiflorus (L.) Kulju & Welzen is a medium sized deciduous tree under the family Euphorbiaceae with Nativity from the Himalaya to Hainan Island. In India it is distribution throughout the hotter parts, moist semi-evergreen tropical forests along river and water courses. The plant is traditionally used in Indian Ayurvedic medicine. Lipid classes and fatty acid compositions of seed oil considered a cheap raw material in surface coating industry. The present study investigated the variation of fatty oil content of M. nudiflora from populations of different agro climatic zone of Assam. Five Agro climatic zone of Assam were selected, extensive field surveys were done for authentication of extent of population and distribution maps were prepared accordingly. Twenty (20) populations were studied; fruits were de pulped and pale yellow coloured oil was extracted with Soxhlet apparatus using hexane as solvent. The highest percentage of oil found in Bilasipara population (25.12±0.17%) of Lower Brahmaputra Valley Zone, and lowest in Kolajan of North Bank Zone (1.51±0.52%). Diversity in specific climato-ecological characteristics of agro climatic zones influenced the variation in oil content of studied populations. Present results facilitated a great opportunity intended for selection of superior population in favour of obtaining high fatty oil yield from seeds M. nudiflorus at commercial scale.

Sinergia de datos espectrales Landsat, climáticos y LiDAR para el mapeo de biomasa aérea en selvas medianas de la península de Yucatán, México

Introduction: Tropical forests represent complex and dynamic ecosystems that cover extensive areas, hence the importance of determining biomass content and representing spatial variability. Objective: Estimating and mapping aboveground biomass and its associated uncertainty for medium-stature semi-evergreen (SMSP) and semi-deciduous (SMSC) tropical forests of the Yucatan Peninsula. Materials and methods: Aboveground biomass was estimated as a function of explanatory variables taken from Landsat images and climatic variables, using the random Forest algorithm. Aboveground biomass was mapped from previous biomass estimates for stripes of the territory with the presence of LiDAR (Light Detection And Ranging) and field data. Uncertainty at the pixel level was estimated as the coefficient of variation. Results and discussion: A combination of climatic and spectral variables showed acceptable capacity to estimate biomass in the medium-stature semi-evergreen and semi-deciduous tropical forest with an explained variance of 50 % and RMSE (root mean squared error) of 34.2 Mg·ha -1 and 26.2 Mg·ha -1 , respectively, prevailing climate variables. SMSP biomass ranged from 4.0 to 185.7 Mg·ha -1 and SMSC ranged from 11.7 to 117 Mg·ha -1 . The lowest values of uncertainty were recorded for the medium-stature semi-evergreen tropical forest, being higher in areas with lower amounts of aboveground biomass. Conclusion: Aboveground biomass was estimated and mapped by the combined use of auxiliary variables with an acceptable accuracy, against uncertainty of predictions, which represents an opportunity for future improvement.

Timorese archaeobotany: An anthracological pilot study at the late Holocene Lepu-Kina rockshelter, Atauro Island, East Timor

This paper details an anthracological pilot study for the Lepu-Kina rockshelter site (AT-7), located on Atauro Island, East Timor and considers the implications of the preliminary results for the archaeology of the region. Archaeological wood charcoal analysis can reveal aspects of fuel selection, human landscape modifications and management of vegetal resources. The difficulties inherent in tropical archaeobotany have, however, constrained anthracological research in Island Southeast Asia. This study is therefore principally an attempt to assess the potential for future anthracological investigations to address archaeological questions related to vegetation resource uses and horticultural practices in Island Southeast Asia. Results reveal that the occupants of the Lepu-Kina rockshelter 2500 years ago had access to abundant semi-evergreen tropical forests and savannah. The presence of Artocarpus, identified as either breadnut or breadfruit (A. cf. altilis/camansi) is also recorded. These results confirm that a more expansive anthracological investigation of the Lepu-Kina rockshelter, accompanied by a local or regional reference collection and wood anatomy resource, has significant potential to expand on these initial observations.