Lowland Evergreen Forest Research Articles

Comparing tree‐ring and permanent plot estimates of aboveground net primary production in three eastern U.S. forests

AbstractForests account for a large portion of sequestered carbon, much of which is stored as wood in trees. The rate of carbon accumulation in aboveground plant material, or aboveground net primary productivity (aNPP), quantifies annual to decadal variations in forest carbon sequestration. Permanent plots are often used to estimate aNPP but are usually not annually resolved and take many years to develop a long data set. Tree rings are a unique and infrequently used source for measuring aNPP, and benefit from fine spatial (individual trees) and temporal (annual) resolution. Because of this precision, tree rings are complementary to permanent plots and the suite of tools used to study forest productivity. Here we evaluate whether annual estimates of aNPP developed from tree rings approximate estimates derived from colocated permanent plots. We studied a lowland evergreen (Howland, Maine), mixed deciduous (Harvard Forest, Massachusetts), and mixed mesophytic (Fernow, West Virginia) forest in the eastern United States. Permanent plots at the sites cover an area of 2–3 ha, and we use these areas as benchmarks indicative of the forest stand. We simulate random draws of permanent plot subsets to describe the distribution of aNPP estimates given a sampling area size equivalent to the tree‐ring plots. Though mean tree‐ring aNPP underestimates permanent plot aNPP slightly at Howland and Fernow and overestimates at Harvard Forest when compared with the entire permanent plot, it is within the 95% confidence interval of the random draws of equal‐sized sampling area at all sites. To investigate whether tree‐ring aNPP can be upscaled to the stand, we conducted a second random draw of permanent plot subsets simulating a twofold increase in sampling area. aNPP estimates from this distribution were not significantly different from results of the initial sampling area, though variance decreased as sampling area approaches stand area. Despite several concerns to consider when using tree rings to reconstruct aNPP (e.g., upscaling, allometric, and sampling uncertainties), the benefits are apparent, and we call for the continued application of tree rings in carbon cycle studies across a broader range of species diversity, productivity, and disturbance histories to fully develop this potential.

Composición y diversidad de especies arbóreas en transectos de localidades del bosque siempreverde de tierras bajas del Ecuador

El estudio se realizó en 9 transectos de 1000m2 de bosque siempreverde de tierras bajas, ubicado en dos localidades de la Costa y una en el oriente ecuatoriano. Se planteó contribuir al conocimiento de la diversidad y composición de plantas arbóreas mayores de 10 cm de diámetro a la altura del pecho (DAP), además de inferir el estado de conservación de los bosques en base en la composición, el número de especies, índices de diversidad y valor de importancia (IV) localizadas en 9 transectos de 1000 m² de bosque. Se encontraron 156 especies, 107 géneros y 39 familias distribuidas en los 9 transectos, en cada uno la diversidad varía según el índice de diversidad de Simpson de 0.95-0.88, en este caso todos son diversos porque se aproxima a 1. La mayoría de las especies no están presentes en todos los transectos, el índice de valor en cada transecto no sobrepasa el 40%. Agrupando los transectos coinciden con las tres localidades efectuadas a excepción del transecto 5 y 8 que fueron realizados en sitios perturbados, es decir la mayoría de transectos tienen una perturbación intermedia por eso sus altos índices de diversidad.

Seed Rain in Abandoned Clearings in a Lowland Evergreen Rain Forest in Southern Thailand

Some forest restoration techniques treat remnant shrubs as competitors of newly planted tree seedlings, often clearing shrubs and weeds before trees are planted, but such plants may have significant value in attracting seed dispersers. In this study we examined the role of remnant trees and shrubs in grassland as a tool for passive and low cost ecological restoration. We determined the species density and abundance of both seed rain and its vertebrate dispersers in relation to different microhabitats (shrub-like vs. tree-like vegetation vs. grassland patches) in a 20–ha clearing of weeds mixed with early successional woody vegetation in a lowland evergreen forest in southern Thailand. We quantified seed rain from 60 seed traps placed in each microhabitat, and compared differences in seed abundance and species richness, while also examining the effect of distance from the forest edge. We found that seed rain abundance and seed species richness were significantly different among microhabitats. Seed rain was highest under shrubs, followed by under trees and then grassland, whereas seed species richness was highest under trees, followed by under shrubs, and grassland. Distance from the forest edge affected seed rain abundance under trees only. Birds (bulbuls and flowerpeckers) were the main dispersers of seeds at trees and shrubs respectively, while bats were the primary dispersers for the grassland patches. Different seed disperser groups appear to have complementary roles, such that sites containing a mixture of vegetation types including early successional vegetation may attract significantly more seed dispersers.

Bat populations in lowland dry evergreen forests of the Central Cardamom Protected Forest in Cambodia

This study was conducted to clarify the characteristics of bat populations in lowland dry evergreen forests of the Central Cardamom Protected Forest in Cambodia during the rainy seasons of 2011–2013 and the dry seasons of 2012–2013. In five study sites of the forest, data from 160 individuals of six bat species were recorded. The Sunda short-nosed fruit bat (Cynopterus brachyotis Sunda) was the most dominant species in all study sites. Most captured bats were adults, and captured females outnumbered captured males. In this study, populations of the bats, except for that of the Sunda short-nosed fruit bats, were not stable. Therefore, forest loss and degradation should be prohibited in the study areas to ensure stable bat populations. Further studies are required to investigate the ecological characteristics of fruit bats in various forest types for the conservation of the mammals and their habitats.

Forest ecosystem changes from annual methane source to sink depending on late summer water balance

AbstractForests dominate the global carbon cycle, but their role in methane (CH4) biogeochemistry remains uncertain. We analyzed whole‐ecosystem CH4fluxes from 2 years, obtained over a lowland evergreen forest in Maine, USA. Gross primary productivity provided the strongest correlation with the CH4flux in both years, with an additional significant effect of soil moisture in the second, drier year. This forest was a neutral to net source of CH4in 2011 and a small net sink in 2012. Interannual variability in the summer hydrologic cycle apparently shifts the ecosystem from being a net source to a sink for CH4. The small magnitude of the CH4fluxes and observed control or CH4fluxes by forest productivity and summer precipitation provide novel insight into the CH4cycle in this globally important forest ecosystem.

Transpiration and Crown Level-stomatal Conductance of Successively and Irregularly Leaf-exchanging Species in a Cambodian Lowland Evergreen Forest

Transpiration and Crown Level-stomatal Conductance of Successively and Irregularly Leaf-exchanging Species in a Cambodian Lowland Evergreen Forest

Physicochemical Surface-soil Properties after Litter-removal Manipulation in a Cambodian Lowland Dry Evergreen Forest

Litter plays key roles in forest ecosystems, and forest degradation is likely to spur a further decline in leaf litterfall inputs to forest soils. However, the effects on physicochemical surface-soil properties remain largely unknown, especially in seasonal tropical forest ecosystems. We initiated a litterremoval manipulation experiment in a Cambodian lowland evergreen forest undergoing intensive selective logging. Litter removal performed for 2 and 4.4 years respectively triggered an increase in bulk density and decrease in surface-soil carbon (C) and nitrogen (N) contents to 67 and 73% of the original levels, respectively. After only 2 years of treatment, bulk density rose to very high value (>1.40 Mg m–3) likely preventing further soil compaction, while the C and N reduction effects lasted over 2 years. Greater soil compaction occurs in stands with a smaller initial bulk density. However, C (N)-rich soils did not necessarily lose a greater relative proportion of C (N) than C (N)-poor soils. Although N remained above C following the litter removal, conservative trends in the C:N ratio suggested a limited capacity for N retention. Together, our data suggest that shifts in leaf litter inputs in response to localized human disturbances may have rapid and lasting consequences on physicochemical surface-soil properties; possibly accelerated by a tropical climate. Moreover, a speedy recovery to an adequate litter supply, at least before reaching the upper soil compaction limit, is essential to conserve forest ecosystems.

A new species of Murina (Mammalia: Chiroptera: Vespertilionidae) from peninsular Thailand.

A new species of Murina belonging to 'suilla-group' is described based on two specimens collected with harp traps in lowland evergreen forest in the southernmost part of peninsular Thailand. Morphology and molecular (mitochondrial COI) data suggest that the new species is most closely related to M. eleryi, which is currently known from Indochina. The new species, however, can be distinguished by the size and shape of the upper canine, the shape of the upper and lower premolars, and the colour of the ventral pelage. Additional data on bacular morphology, echolocation, ecology, and distribution are included.

Three new or resurrected species of Leptonychia (Sterculiaceae- Byttneriaceae-Malvaceae) from West-Central Africa

The name Leptonychia kamerunensis Engl. & K. Krause is resurrected for an understorey tree of submontane forest in the Cameroon Highlands. L. subtomentosa K. Schum. is resurrected for a tree of the hilly semi-deciduous forests around Yaounde in Central Province, Cameroon. L. moyesiae Cheek, a shrub of lowland coastal evergreen forest of SE Nigeria, SW Province Cameroon and Bioko, is newly described. The taxonomic affinities and conservation status of these three species are assessed.

Predicted distributions and conservation status of two threatened Southeast Asian small carnivores: the banded civet and Hose’s civet

Abstract Knowledge of the distribution and habitat preferences of a species is of paramount importance when assessing its conservation status. We used accurately recorded occurrence records and ecological niche modelling to predict the distribution of two threatened and poorly known small carnivore species that occur in Southeast Asia, the banded civet (Hemigalus derbyanus) and Hose’s civet (Diplogale hosei), and analysed their spatial niche differentiation for habitat and elevation. We then identified possible anthropogenic threats, and used our modelling predictions to recommend surveying priorities. The predicted distribution of the banded civet was principally in lowland evergreen forest in southern Myanmar/Thailand, Peninsular Malaysia, Sumatra, Borneo and three Mentawai Islands (Siberut, Sipora and South Pagai), and for Hose’s civet in evergreen forest across the higher elevation regions of Borneo. Our niche analyses suggested that there is a tendency for these two species to separate spatially along an elevation gradient: the banded civet is mainly found in lowland areas, whereas Hose’s civet primarily occurs at higher elevations. Our study strongly indicated that these two viverrids are forest-dependent species that may be threatened by forest loss, degradation and fragmentation. Field surveys should be prioritised in areas where each species is predicted to occur and no records currently exist.

Year-to-Year Differences in Sap Flow and Crown-Level Stomatal Conductance of Two Species in a Lowland Evergreen Forest, Central Cambodia

Although information about the hydrologic and ecological features of lowland evergreen forests in central Cambodia has been collected since the beginning of the 21st century, measurements of the transpiration process remain very limited. This paper describes the differences detected in transpiration (q) and crown-level stomatal conductance (GS) between Calophyllum inophyllum (which undergoes successive leaf exchange) and Drypetes sp. (which performs irregular leaf exchange) (hereafter referred to as Calophyllum and Drypetes, respectively), and the analysis of these differences in consideration of their contrasting leaf phenologies. We evaluated q using sap flow measurements and obtained daily GS values. Calophyllum and Drypetes had high and low periods between which q and GS differed significantly. Within high/low periods, smaller scatter in the plot of GS versus vapour pressure deficit (D) was found in Calophyllum compared to Drypetes. For a given value of D, q in high periods was 1.3 and 1.9 times larger than in low periods for Calophyllum and Drypetes, respectively. The smaller scatter for Calophyllum was the result of relatively constant physiological activity that was maintained by successive leaf fall.For both species, high periods were recorded after remarkable leaf-fall events; thus, our current data implied that leaf phenology is one of the most important factors affecting transpiration.

New molecular data on Pyrenulaceae from Sri Lanka reveal two well-supported groups within this family

AbstractPyrenulaceae is one of the dominant lichen families in the tropics, especially in lowland evergreen forests. Although very species-rich, phylogenetic relationships within Pyrenulaceae have not been extensively studied using molecular data, and its morphology-based generic delimitation remains untested. A recent lichenological survey carried out in the Knuckles Mountain Range in Sri Lanka allowed the first author to collect fresh specimens of different species of Pyrenula, and to investigate the phylogenetic relationships within the family Pyrenulaceae using a multigene analysis (ITS, nuLSU and mtSSU) and a preliminary dataset of 21 taxa. This data shows that the family Pyrenulaceae can be divided into two well-supported groups and suggests that the genus Pyrenula is not monophyletic. Characters usually used for generic classification in this family (ascospore colour and septation, structure of the ascospore locules, secondary chemistry, hamathecium structure, ostiole position) do not correlate with these two groups. However, the presence of pseudocyphellae is restricted to species of Pyrenula from one group.

ANALISIS TATA RUANG (ZONASI) PENGEMBANGAN EKOWISATA DI KAWASAN TAMAN NASIONAL BALURAN JAWA TIMUR

Research on potential ecotourism development at Baluran National Park which consists more than 25.000 Hectares area and coast line about 42 km long has been conducted from June to September 2003 in the local communities area around Baluran National Park and 5 ecosystems type such as mangrove forest, lowland tropical forest, deciduous forest, evergreen forest, and grassland. The objectives of this study were to definited the zonation for ecotourism. For these, research was initiated to inventory ecotourism supply such are biophysic attractions, socio culture local people attractions, tour object around Baluran National Park and facilities attractions. In order to obtain data and information for ecotourism demand of tourist and local people characteristic included activity, interest and opinion data were collected through questionnaires and open-ended interviews. The collected data were analyzed by using zonation analysis for ecotorism landscape. Based on the zonation analysis revealed that at Baluran National park obtained 3 zonation that could further develop for ecotourism: (1) mangrove and coral reef ecotourism zonation, (2) savana and forest ecotourism zonation, (3) village ecotourism zonation. Kind of attraction for ecotourism on each zonation are biodiversity of flora and fauna, coral reef, etnobotany information and cultural local people activities.

Effects of seed traits on the success of direct seeding for restoring southern Thailand’s lowland evergreen forest ecosystem

The success of direct seeding, as a low-cost approach to forest restoration, varies with tree species and seed characteristics. A system to predict which tree species are likely to be suitable for direct seeding would therefore be useful for improving forest restoration projects. Therefore, this study aimed to determine the effects of seed traits on the success of direct seeding to restore tropical forest in southern Thailand. Seeds of 19 indigenous lowland tropical forest tree species were collected, from both the east and west sides of the Thailand peninsular and the following parameters measured: seed size, shape, coat thickness and moisture content. Field trials were established to determine seed germination rates and to calculate a “direct seeding suitability score” for each species, which combined seedling establishment and growth rates. Seed size, shape and moisture content were associated with germination percentage. Species with higher seedling survival tended to have large or intermediate-sized seeds, round or oval seeds and seeds with low or medium moisture content. Only seed coat thickness was significantly correlated with the suitability score (r = 0.65, p 0.4 mm coincided with higher rank suitability score. These conditions successfully predicted the success or failure of direct seeding for 15 out of 19 species tested. Eight tree species are recommended as suitable for restoring lowland evergreen forest ecosystems in southern Thailand, by direct seeding.

Eocene out-of-India dispersal of Asian dipterocarps

The Dipterocarpaceae, a well known and economically important family of trees of the tropical rain forests of Asia, comprise over 470 species. These angiosperm trees contribute to 30% of the total area in typical lowland evergreen forests in Southeast Asia. Despite their remarkable diversity and regional ecological dominance, the origins and phytogeographical evolution of the family are poorly understood. The earliest dipterocarp fossils recorded in SE Asia come from Oligocene (34–23 Ma) sediments of Borneo. Here, we report an occurrence of Asian dipterocarps from approximately 53 Ma old sediments from western India based on fossil resin chemistry and palynological data. An important implication of our finding is that Asian dipterocarps must have originated in Gondwana and dispersed from India into Asia once the land connection between the Indian and Asian plate was well established during the middle Eocene (49–41 Ma). Moreover, the present study supports the hypothesis which suggests that many angiosperms did not originate in the SE Asian region, but dispersed into the area from western Gondwanaland.

Deforestation rates in insular Southeast Asia between 2000 and 2010

Insular Southeast Asia experienced the highest level of deforestation among all humid tropical regions of the world during the 1990s. Owing to the exceptionally high biodiversity in Southeast Asian forest ecosystems and the immense amount of carbon stored in forested peatlands, deforestation in this region has the potential to cause serious global consequences. In this study, we analysed deforestation rates in insular Southeast Asia between 2000 and 2010 utilizing a pair of 250 m spatial resolution land cover maps produced with regional methodology and classification scheme. The results revealed an overall 1.0% yearly decline in forest cover in insular Southeast Asia (including the Indonesian part of New Guinea) with main change trajectories to plantations and secondary vegetation. Throughout the region, peat swamp forests experienced clearly the highest deforestation rates at an average annual rate of 2.2%, while lowland evergreen forests declined by 1.2%/yr. In addition, the analysis showed remarkable spatial variation in deforestation levels within the region and exposed two extreme concentration areas with over 5.0% annual forest loss: the eastern lowlands of Sumatra and the peatlands of Sarawak, Borneo. Both of these areas lost around half of their year 2000 peat swamp forest cover by 2010. As a whole this study has shown that deforestation has continued to take place on high level in insular Southeast Asia since the turn of the millennium. These on-going changes not only endanger the existence of numerous forest species endemic to this region, but they further increase the elevated carbon emissions from deforested peatlands of insular Southeast Asia thereby directly contributing to the rising carbon dioxide concentration in the atmosphere.

Psychotria monensissp. nov (Rubiaceae), a tree species from Cameroon

Psychotria monensis Cheek & Séné (Rubiaceae) from lowland evergreen forest in western Cameroon is described and illustrated. Its conservation status is assessed as ‘Critically Endangered’ according to the IUCN criteria, and its taxonomic affinities are discussed.

Estimating Diameter at Breast Height from Measurements of Illegally Logged Stumps in Cambodian Lowland Dry Evergreen Forest

The Reducing Emissions from Deforestation and Forest Degradation in Developing Countries (REDD) initiative requires accurate estimates of carbon stock changes in forested areas. However, estimating carbon emissions from stumps of various heights left by illegal loggers is difficult. To remedy this problem, we examined two methods of estimating diameter at breast height (DBH) from a reference diameter observation measured at any stump height. The one-reference diameter (OD) observation model estimates DBH from a single diameter observation using empirical coefficients derived mainly from emergent dipterocarp trees. The two-reference diameter (TD) observation model estimates DBH from two diameter observations and assumes a logarithmic relationship between diameter and height. Prediction data to establish the models were collected in Cambodian lowland evergreen forests that are undergoing intensive illegal logging of emergent dipterocarp trees for timber. The OD model performed better than the TD model in predicting DBH and is extremely practical, as it requires only a single diameter observation. Validation data previously collected in the Southeast Asian tropical forests established the general validity of the OD model. This study may improve the reliability of the REDD scheme by providing a reliable method to assess carbon emissions from Southeast Asian tropical forests.

Bio‐indicator species and Central African rain forest refuges in the Campo‐Ma'an area, Cameroon

This study aims to examine the geographical position of late Pleistocene forest refuges in the tropical lowland rain forest in southern Cameroon by analysing the distribution of 178 selected bio‐indicator species. We studied the distribution patterns of these species, such as strict and narrow endemics, as well as a number of well‐known slow dispersal species, to test whether the entire Campo‐Ma'an rain forest was part of a late Pleistocene rain forest refuge. Special attention was given to taxa with slow dispersal abilities such as those within Begonia sect. Loasibego‐nia and sect. Scutobegonia, Rinorea spp. , Caesalpinioideae and Rubiaceae. Species that occur in other rain forest refuges and that reach their northern limit of distribution in the Campo‐Ma'an area were also included in the analysis. The distribution patterns of the 178 bio‐indicator species were displayed in several maps. There was a high concentration of bio‐indicator species in the lowland evergreen forest rich in Caesalpinioideae, and in the submontane forests in the National Park and in the Kribi‐Campo‐Mvini area, and a relatively low concentration of these species in the Ma'an area. Similar patterns were observed for the distribution of strict and narrow endemic species, Begonia, Caesalpinioideae and Rubiaceae. Most of these species were particularly frequent on higher altitudes in the lowland rain forests, especially along the upper slopes of hills near the top, or along riverbanks. There was a relatively even distribution of bio‐indicator species from the Rubiaceae family within the Campo‐Ma'an area. The distribution of Begonia showed that some species were frequent in mountainous areas, along slopes near hilltops in the lowland forest and others were located along small streams in the lowland forest. As for the Caesalps, their distribution showed a high concentration of species in the evergreen forest rich in Caesalpinioideae with a decrease in number in the coastal forest and the mixed evergreen and semi‐deciduous forest. As for the Rinorea, many indicator species were mostly confined to the lowland forest, particularly in the evergreen forest rich in Caesalpinioideae. These species distribution patterns corroborate the view of many authors who argue that during glacial times forests were restricted to the upper slopes of hills, upper altitudinal zones in the lowland forests, or along riverbanks. Our findings, therefore, suggest that the Campo‐Ma'an area falls within a series of postulated rain forest refuges in Central Africa as proposed by previous authors.

Evapotranspiration Characteristics of a Lowland Dry Evergreen Forest in Central Cambodia Examined Using a Multilayer Model

Development pressure has led to serious deforestation on the Indochina Peninsula. Particularly rapid defor-estation has occurred in easily accessible lowland areas, and it is thus important to accumulate knowledge about these forests immediately. We measured evapotranspiration rates for a lowland dry evergreen forest in Kampong Thom Province, central Cambodia, using the energy balance Bowen ratio (EBBR) method based on meteorological data collected from a 60-m-high observation tower. Daily evapotranspiration was higher during the dry season than during the rainy season of the Asian monsoon climate. The seasonal variation in evapotranspiration generally corresponded to the seasonal difference in the vapor pressure deficit. A multi-layer model was used to simulate the seasonal variation in evapotranspiration. The multilayer model also reproduced the larger evapotranspiration rate in the dry season than in the rainy season. However, observed values substantially exceeded model-calculated results during certain periods at the beginning of the dry season and in the late dry season. Moreover, during the rainy season, the model tended to overestimate evapotranspiration. The differences between these observed and simulated values may have been caused by seasonal characteristics of photosynthesis and transpiration in the lowland dry evergreen forest that were not considered in the model simulation.