Trisurat Y.,Kasetsart University |
Eawpanich P.,Wildlife and Plant Conservation |
Kalliola R.,University of Turku
Environmental Research | Year: 2016
The Thadee watershed, covering 112 km2, is the main source of water for agriculture and household consumption in the Nakhon Srithammarat Province in Southern Thailand. As the natural forests upstream have been largely degraded and transformed to fruit tree and rubber plantations, problems with landslides and flooding have resulted. This research attempts to predict how further land-use/land-cover changes during 2009-2020 and conceivable changes in rainfall may influence the future levels of water yield and sediment load in the Thadee River. Three different land use scenarios (trend, development and conservation) were defined in collaboration with the local stakeholders, and three different rainfall scenarios (average rainfall, climate change and extreme wet) were determined on the basis of literature sources. Spatially explicit empirical modelling was employed to allocate future land demands and to assess the contributions of land use and rainfall changes, considering both their separate and combined effects. The results suggest that substantial land use changes may occur from a large expansion of rubber plantations in the upper sub-watersheds, especially under the development land use scenario. The reduction of the current annual rainfall by approximately 30% would decrease the predicted water yields by 38% from 2009. According to the extreme rainfall scenario (an increase of 36% with respect to current rainfall), an amplification of 50% of the current runoff could result. Sensitivity analyses showed that the predicted soil loss is more responsive to changes in rainfall than to the compared land use scenarios alone. However, very high sediment load and runoff levels were predicted on the basis of combined intensified land use and extreme rainfall scenarios. Three conservation activities-protection, reforestation and a mixed-cropping system-are proposed to maintain the functional watershed services of the Thadee watershed region. © 2016 Elsevier Inc..
Vlam M.,Wageningen University |
Baker P.J.,University of Melbourne |
Bunyavejchewin S.,Wildlife and Plant Conservation |
Zuidema P.A.,Wageningen University
Oecologia | Year: 2014
Climate change effects on growth rates of tropical trees may lead to alterations in carbon cycling of carbon-rich tropical forests. However, climate sensitivity of broad-leaved lowland tropical trees is poorly understood. Dendrochronology (tree-ring analysis) provides a powerful tool to study the relationship between tropical tree growth and annual climate variability. We aimed to establish climate-growth relationships for five annual-ring forming tree species, using ring-width data from 459 canopy and understory trees from a seasonal tropical forest in western Thailand. Based on 183/459 trees, chronologies with total lengths between 29 and 62 years were produced for four out of five species. Bootstrapped correlation analysis revealed that climate-growth responses were similar among these four species. Growth was significantly negatively correlated with current-year maximum and minimum temperatures, and positively correlated with dry-season precipitation levels. Negative correlations between growth and temperature may be attributed to a positive relationship between temperature and autotrophic respiration rates. The positive relationship between growth and dry-season precipitation levels likely reflects the strong water demand during leaf flush. Mixed-effect models yielded results that were consistent across species: a negative effect of current wet-season maximum temperatures on growth, but also additive positive effects of, for example, prior dry-season maximum temperatures. Our analyses showed that annual growth variability in tropical trees is determined by a combination of both temperature and precipitation variability. With rising temperature, the predominantly negative relationship between temperature and growth may imply decreasing growth rates of tropical trees as a result of global warming. © 2013 Springer-Verlag Berlin Heidelberg.
Matsui N.,Kanso Technos Co. |
Morimune K.,Kansai Electric Power Co. |
Meepol W.,Ranong Mangrove Forest Research Center |
Chukwamdee J.,Wildlife and Plant Conservation
Forests | Year: 2012
Forest carbon stocks-both in terms of the standing biomass and the soil organic carbon (OC)-were monitored in the mangrove plantation reforested from an abandoned shrimp pond for the 10 years following land excavation. Excavation to a level of 25 cm below the existing ground level increased the inundation time of tidal water from 463 to 7,597 hours per year, resulting in a significant increase of survival/growth rates for planted mangrove species, Rhizophora mucronata (RM) and Bruguiera cylindrica (BC), and of carbon stocks as well. RM showed high rates of standing biomass accumulation with 98.7 ton/ha while 28.8 ton/ha for BC was measured over 10 years in the excavated area. In contrast, the unexcavated area showed low rates of biomass accumulation, 1.04 ton/ha for RM and 0.53 ton/ha for BC in the same period. The excavated area recorded a twofold increase of soil OC in the upper 5 cm of the surface soil from 71.8 to 154.8 ton/ha in 10 years, however it decreased to 68.3 ton/ha in the unexcavated area where soil OC is susceptible to decomposition. These results imply that the potential of carbon sinks in reforested land from abandoned areas cannot be developed unless hydraulic conditions are properly recovered. The fast growing species Avicennia marina (AM) grew quickly for the first two years after colonization but its growth slowed down afterwards, showing a limited ability of carbon capture. © 2012 by the authors.
Trisurat Y.,Kasetsart University |
Bhumpakphan N.,Kasetsart University |
Reed D.H.,University of Louisville |
Kanchanasaka B.,Wildlife and Plant Conservation
Journal for Nature Conservation | Year: 2012
Rapid deforestation has occurred in northern Thailand and is expected to continue. Thus, identification and protection of sufficient amounts of the highest quality habitat is urgent. Wildlife occurrence data were gathered along wildlife trails and patrolling routes in protected areas and forest patches outside of protected areas. Geographic Information Systems, bio-physical and anthropogenic variables were used to generate suitable habitats for 17 mammal species using maximum entropy theory (MAXENT). Suitable habitats for all species were aggregated, and used to set priorities for wildlife conservation in northern Thailand. In addition, predicted deforestation was overlaid on moderate and high priority areas to determine future wildlife threats and aid decision-making concerning which areas to protect. The results revealed that the total extent of suitable habitats for the studied species covers approximately 37% of the region. Nearly 70% of the total habitat for endangered and vulnerable species is predicted in large and contiguous protected areas. Threatened areas with high biodiversity encompass approximately 1.9% of the region, and 66% of this figure is predicted to occur in existing protected areas. Based on the model outcomes, we recommend reducing human pressures, enhancing the density of prey species and conservation outside protected areas, as well as increasing connectivity of suitable habitats among protected areas that are too small to maintain viable populations in isolation. © 2012 Elsevier GmbH.
The study by the wildlife trade monitoring network, TRAFFIC, and the Center for International Forestry Research (CIFOR) is based on research by Lancaster University's Dr Jacob Phelps. Conservative trade figures documented during the study suggest that tens of thousands of orchids are illegally traded across Thailand's borders every year, without either domestic harvest permits or Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) permits, violating range State and international restrictions on wild orchid harvest. Surveys during 2011–2012 in four of the largest wild plant markets in Thailand, including along the country's borders with Myanmar and Lao PDR, recorded 348 species of orchid for sale, representing 13 to 22 percent of the target countries' known orchid flora. The survey even found significant trade of species from the genus Paphiopedilum, all of which are listed in Appendix I of CITES, which bans the international trade of wild-collected specimens. At least 16 percent of the orchid species observed could be classified under some category of threat or were species found only in small or specific areas. The threat, however, is likely much higher since conservation status assessments have not been conducted for most of the species encountered. Several of the orchids first found in the markets were new to science. 'A Blooming Trade: Illegal trade of ornamental orchids in mainland Southeast Asia' identified Bangkok's Chatuchak market as a regional centre of botanical trade, hosting a large and unique richness of wild plant species, many of them illegally harvested. "The Chatuchak market has long been notorious as a major hub for the illegal trade in a wide variety of plants and animals—everything from orchids to tortoises, from ivory to eagles," said Dr Chris R. Shepherd, Regional Director for TRAFFIC in Southeast Asia. "We strongly urge the authorities in Thailand to shut down the illegal trade in this market for good." Report author Dr Phelps said: "The commercial trade of wild-collected ornamental plants in Southeast Asia is part of a global horticultural trade in beautiful, fragrant and unusual plant species but it has been almost completely overlooked. Despite being among the most protected group of plants in the world, we found clear evidence of an open, illegal trade. It is time to take botanical trade and conservation seriously - alongside efforts to reduce the illegal trades in elephant ivory, rhinoceros horn and pangolin scales. This is no different." Interviews with plant harvesters, traders and middlemen identified significant illegal international trade from Lao PDR and Myanmar into Thailand, highlighting demand for wild ornamental plants from local and regional sources. It also revealed complex trade chains involving highly organized middlemen specialized in the orchid and ornamental plant trade. Growing internet based trade and laundering of wild plants via registered commercial greenhouses was observed, as was a medicinal trade in orchids for consumption in Viet Nam and China. The report calls on Thai government agencies, CITES parties, the ASEAN Wildlife Enforcement Network and conservation organizations to formally recognize the phenomenon, and urgently improve monitoring of not only the trade in charismatic animals species, but also of wild plants. The author also argues that the considerable implications of the illegal trade warrant far greater attention from Thailand's CITES management authority for plants, as well as the Department of National Parks, Wildlife and Plant Conservation and the Royal Forest Department. More information: A blooming trade: Illegal trade of ornamental orchids in mainland Southeast Asia (Thailand, Lao PDR, Myanmar). static1.1.sqspcdn.com/static/f/157301/26694012/1448362157923/A+blooming+trade+Report+_+17th+Nov_FINAL.pdf?token=YeQt5ctv%2FbPNaRO8QJECOl%2BYPNQ%3D