Browsing by SDGs "[SDGs]SDG15"

Multi-use forest planning is not an easy task for forest managers because of the difficulty in defining a clear set of competing goals. Multi-choice goal programming (MCGP) can get an ideal solution more quickly for the multi-use forest problems by setting various target goal values for each goal. However, decision-makers may miss a better one if the set of target goal values are far from the best ideal solution. The purpose of this paper is to propose a new algorithm (3-level MCGP) which can complete the insufficiency of the MCGP technique by combining binary search algorithm to reduce the number of comparison in MCGP method and then achieve the best ideal solution as close as possible. Building on the results of a published case by goal programming (GP), this paper demonstrates that a more favorable alternative could be discovered by the new algorithm in a few steps. Through the re-allocation of forestland by the 3-level MCGP, forest managers can increase preferred forest production without losing the other minor production. The results of this study also indicated that, the 3-level MCGP is an efficient technique that can help forest managers to obtain an appropriate resource allocation and even achieve more forest production. © 2011 Taylor & Francis.

Steep terrain and fragile geology in the mountainous area in Taiwan makes the slope susceptible to landslides during heavy rainfall and earthquakes. In 1999, the Chi-Chi Earthquake induced a great deal of landslides in central Taiwan. It is dubious if the weakening of the slope material by the earthquake still influences slope stability and changes the landslide-triggering threshold in some rainfall characteristics. Typhoon Polly in 1992, Herb in 1996, Toraji in 2001 and Mindulle in 2004 are selected for study. The former two took place before the Chi-Chi Earthquake, while the other two occurred after it. Aerial photos are interpreted to identify landslides triggered by each of the typhoons, and individual landslide is then delineated and digitized. Based on the 40 meter resolution DEM, terrain attributes such as size, slope, slope location and specific catchment area for each landslide are calculated using and the results are statistically analyzed. In addition, SINMAP is applied to back calculate the internal frictional angle of each geologic stratum during corresponding typhoon. It is concluded on the calculation results that (1) the fragile metamorphic strata are more subjected to landslides than the sedimentary strata. However, after the Chi-Chi Earthquake, landslides in the sedimentary strata have increased a lot. (2) Both before and after the Chi-Chi Earthquake, the number and area of the landslides increase with increasing rainfall intensities. (3) In all the three sub-watersheds, the estimated internal frictional angles of the slope material after the earthquake tend to be smaller than those took place before the earthquake. (4) The average specific catchment area for the landslides which took place after the earthquake also tends to be smaller than those before the quake. (5) The internal frictional angles of the metamorphic rock after the earthquake are also smaller than it was before. It is shown that the Chi-Chi Earthquake weakened slope material, but since most part of the loose materials has slipped away and vegetation has colonized the once stripped ground surface, the after effects of the Chi-Chi Earthquake have been alleviated.

How diversity influences the stability of a community function is a major question in ecology. However, only limited empirical investigations of the diversity-stability relationship in soil microbial communities have been undertaken, despite the fundamental role of microbial communities in driving carbon and nutrient cycling in terrestrial ecosystems. In this study, we conducted a microcosm experiment to investigate the relationship between microbial diversity and stability of soil decomposition activities against changes in decomposition substrate quality by manipulating microbial community using selective biocides. We found that soil respiration rates and degradation enzyme activities by a coexisting fungal and bacterial community (a taxonomically diverse community) are more stable against changes in substrate quality (plant leaf materials) than those of a fungi-dominated or a bacteria-dominated community (less diverse community). Flexible changes in the microbial community composition and/or physiological state in the coexisting community against changes in substrate quality, as inferred by the soil lipid profile, may be the mechanism underlying this positive diversity-stability relationship. Our experiment demonstrated that the previously found positive diversity-stability relationship could also be valid in the soil microbial community. Our results also imply that the functional/taxonomic diversity and community ecology of soil microbes should be incorporated into the context of climate-ecosystem feedbacks. Changes in substrate quality, which could be induced by climate change, have impacts on decomposition process and carbon dioxide emission from soils, but such impacts may be attenuated by the functional diversity of soil microbial communities. © 2013 Ushio et al.

In this study we chose Fujian and Taiwan for a comparative case study of cultivated land changes. Separated by a short strait, these two regions are similar in biophysical and cultural characteristics but differ in the level of economic development. Taiwan is ahead of Fujian by 15 to 20 years in economic development. We compared quantitative and qualitative changes of cultivated land in these two regions, and analyzed the proximate causes and the driving forces for cultivated land changes over time. The study showed a time lag, similar to that of economic development, in the dynamic (i.e., greater rates of change) period of cultivated land changes and the ranking of major driving forces. The results suggest that similar land-use changes can occur in different regions as the regions pass through comparable stages of economic development at different times. © 2006 Elsevier Ltd. All rights reserved.

Two contrasting localized heavy rainfall events during Taiwan's early summer rainy season with the daily rainfall maximum along the windward mountain range and coast were studied and compared using a combination of observations and numerical simulations. Both events occurred under favorable large-scale settings including the existence of amoisture tongue from the tropics. For the 31 May case, heavy rainfall occurred in the afternoon hours over the southwestern windward slopes after a shallowsurface front passed central Taiwan. The orographic lifting of the prevailing warm, moist, west-southwesterly flow aloft, combined with a sea breeze-upslope flow at the surface provided the localized lifting needed for the development of heavy precipitation. On 16 June before sunrise, pronounced orographic blocking of the warm, moist, south-southwesterly flow occurred because of the presence of relatively cold air at low levels as a result of nocturnal and rain evaporative cooling. As a result, convective systems intensified as they moved toward the southwestern coast. During the daytime, the cold pool remained over southwestern Taiwan without the development of onshore/upslope flow. Furthermore, with a south-southwesterly flow aloft parallel to terrain contours, orographic lifting aloft was absent and preexisting rain cells offshore diminished after theymoved inland.Over northern Taiwan on the lee side, a sea breeze/onshore flow developed in the afternoon hours, resulting in heavy thundershowers. These results demonstrate the importance of diurnal and local effects on determining the location and timing of the occurrences of localized heavy precipitation during the early summer rainy season over Taiwan. © 2014 American Meteorological Society.

This work utilizes bird survey data, regression modeling, land-use modeling and landscape metrics to evaluate the effects of various spatial bird diversity conservation approaches on land-use allocation, land-use patterns, and biodiversity in the Shangan sub-watershed in central Taiwan. A survey of the distribution of species revealed that bird species are concentrated in the central and western parts of the sub-watershed. The results obtained using a Shannon-Weaver diversity regression model suggest that diversity of land-use increases the diversity of bird species. Logistic regression results verify that socio-economic factors determine the potential advantages of designating a particular type of land-use in certain parts of the study area. The results of land-use simulation modeling indicate that the eastern and southwestern areas of the sub-watershed will change most frequently between 2007 and 2017. Additionally, increasing the areas to protect bird diversity will effectively increase the patch size, habitat core area, edge effect and habitat connectivity. The Shannon-Weaver diversity regression model shows that protecting bird species diversity in large areas increases bird diversity. The proposed modeling approach is an effective tool that provides useful information for ecological planning and policymaking related to watersheds. © 2011.

This study aimed at developing a location-allocation model for senior citizens communities planning. The developed model was applied to the case study of Wanhua District, Taipei City, to verify the applicability and reasonableness of model. The planning results of case study offer concrete recommendations to Taipei City Government. This study employed land-use suitability analysis and mathematical programming approach to design the model as a multi-objective mixed integer programming problem. The model considers three objectives for different stakeholders: maximizing environmental suitability, maximizing developed dwelling units and minimizing development costs, with the following constraints: upper and lower bounds of development scale for each site, dwelling unit demands and value ranges of decision variables. According to the model characteristics, this study applied ε-constraint method to solve the developed model.

Widely distributed groups of living animals, such as the predominantly marine fish family Sciaenidae, have always attracted the attention of biogeographers to document the origins and patterns of diversification in time and space. In this study, the historical biogeography of the global Sciaenidae is reconstructed within a molecular phylogenetic framework to investigate their origin and to test the hypotheses explaining the present-day biogeographic patterns. Our data matrix comprises six mitochondrial and nuclear genes in 93 globally sampled sciaenid species from 52 genera. Within the inferred phylogenetic tree of the Sciaenidae, we identify 15 main and well-supported lineages; some of which have not been recognized previously. Reconstruction of habitat preferences shows repeated habitat transitions between marine and euryhaline environments. This implies that sciaenids can easily adapt to some variations in salinity, possibly as the consequence of their nearshore habitats and migratory life history. Conversely, complete marine/euryhaline to freshwater transitions occurred only three times, in South America, North America and South Asia. Ancestral range reconstruction analysis concomitant with fossil evidence indicates that sciaenids first originated and diversified in the tropical America during the Oligocene to Early Miocene before undergoing two range expansions, to Eastern Atlantic and to the Indo-West Pacific where a maximum species richness is observed. The uncommon biogeographic pattern identified is discussed in relation to current knowledge on origin of gradients of marine biodiversity toward the center of origin hypothesis in the Indo-West Pacific. © 2015 Elsevier Inc.

A 3-D hydrodynamic model (Regional Ocean Modeling System) is used to investigate the dynamics and structure of hyperpycnal river plumes over sloping continental shelves. The focus is on the plume's response to varying slopes and settling velocities (ws). The idealized model is configured to represent small mountainous river systems during a flood event. A hyperpycnal sediment concentration of 60 g/L is specified at the river mouth such that the sediment-freshwater mixture is denser than the seawater, causing the plumes to traverse the shelves as undercurrents. A realistic range of shelf slope of 0.001-0.03 is chosen. The settling velocity is varied based on river's carrying capacity. The model-derived velocity profiles and the entrainment rate compare favorably against prior laboratory experiments. Both cross-shore and alongshore momentum balances are primarily between gravitational forcing and bottom friction. But, the Coriolis deflection is significant at the plume core in the alongshore momentum budget (i.e., Ekman balance). As the slope increases and settling velocity decreases, hyperpycnal plumes transition from depositional to autosuspending regime. An estimate of critical slope governed by a dimensionless parameter ws3/qb (qb is buoyancy input) reasonably captures the regime transition. In the depositional regime, the plume's runout (cross-shore penetration) scales with advective distance: increasing slopes and discharge enhance the gravitational forcing and plume velocity, leading to an increase in runout. In contrast, increasing settling velocity shortens the vertical settling time, thereby reducing the plume's horizontal footprint. For the range of parameters considered, the runout of depositional plumes is confined within 15 km from the mouth, whereas the penetration of autosuspending plumes is essentially unlimited. ©2013. American Geophysical Union. All Rights Reserved.

Understanding the spatial characteristics of dengue fever (DF) incidences is crucial for governmental agencies to implement effective disease control strategies. We investigated the associations between environmental and socioeconomic factors and DF geographic distribution, are proposed a probabilistic risk assessment approach that uses threshold-based quantile regression to identify the significant risk factors for DF transmission and estimate the spatial distribution of DF risk regarding full probability distributions. To interpret risk, return period was also included to characterize the frequency pattern of DF geographic occurrences. The study area included old Kaohsiung City and Fongshan District, two areas in Taiwan that have been affected by severe DF infections in recent decades. Results indicated that water-related facilities, including canals and ditches, and various types of residential area, as well as the interactions between them, were significant factors that elevated DF risk. By contrast, the increase of per capita income and its associated interactions with residential areas mitigated the DF risk in the study area. Nonlinear associations between these factors and DF risk were present in various quantiles, implying that water-related factors characterized the underlying spatial patterns of DF, and high-density residential areas indicated the potential for high DF incidence (e.g., clustered infections). The spatial distributions of DF risks were assessed in terms of three distinct map presentations: expected incidence rates, incidence rates in various return periods, and return periods at distinct incidence rates. These probability-based spatial risk maps exhibited distinct DF risks associated with environmental factors, expressed as various DF magnitudes and occurrence probabilities across Kaohsiung, and can serve as a reference for local governmental agencies. © 2014 Chiu et al.

We found some obvious abnormal strain induced by heavy rainfall from borehole strain-meters deployed in Western Taiwan. The strain induced by rainfall can be divided into two parts, one is the quick response for extra loads of rainwater on the ground, and another one is the slow response for rainwater infiltrating into the strata. The quick and slow rainfall responses of areal strain data are analyzed using the technique of recursive digital filtering. Moreover, the rainfall impact functions of the studied stations are calculated using deconvolution. We found, in most cases, the response strain will reach the maximum in half an hour after heavy rainfall, and then show an exponential decay, it might persist more than 200 h depending on the hydrogeological condition around the station. Whereas the river flowing beside the station will help accelerating the runoff dispersion and reducing rainfall decay time in the hill or mountain region. We also compare the results after calibration in term of isotropic and vertical coupling individually. We found that the response strains are smaller in vertical coupling rather than isotropic coupling. The effects of debris avalanches caused by intensive rainfall in the mountain areas can be viewed as two types of rock deformation: generated only under the influence of rainfall and generated by the increased load in the river channels due to rainfall-induced landslides or debris flow. When the cumulative rainfall exceeds a certain threshold, the strain response curves show a noticeable anomaly likely due to the effects of the debris flow events in places prone to landslides. ? 2021 by the authors. Licensee MDPI, Basel, Switzerland.

[1] Abrupt decreases of the Atlantic meridional overturning circulation (MOC) during the Late Pleistocene have been directly linked to catastrophic discharges of glacimarine freshwater, triggering disruption of northward marine heat transport and causing global climate changes. Here we provide measurements of excess sedimentary 231Pa/230Th from a high-accumulation sediment drift deposit in the NE Atlantic that record a sequence of sudden variations in the rate of MOC, associated deep ocean ventilation and surface-ocean climatology. The data series reveal a sequential decrease in the MOC rate at ∼18.0 ka BP ago that coincides with only transient and localized freshwater inputs. This change represents a substantial, though not total, cessation in MOC that predates the major Heinrich (H1) meltwater event by at least 1,200 years. These results highlight the potential of targeted freshwater perturbations in promoting substantial MOC changes without a direct linking with catastrophic freshwater surges. Copyright 2006 by the American Geophysical Union.

Sediment samples (213 sites) collected from the tectonic-active continental margin, offshore southwestern Taiwan were analyzed for grain sizes, organic carbon, nitrogen and carbon isotopic composition to obtain mass accumulation rate of terrestrial organic carbon and carbon budget to evaluate fate of terrestrial organic carbon from small mountainous rivers on the continental margin offshore southwestern Taiwan. Terrestrial organic carbon accumulation rates range from 0.29 to 45.6gCm-2yr-1 with a total accumulation budget of 0.063Mtyr-1, which accounts for less than 13% of total river particulate organic carbon loads exported from the adjacent rivers, the Gaoping (a.k.a., Kaoping), Erhjen and Tsengwen rivers. This low burial efficiency of terrestrial organic carbon demonstrated that a majority of river-borne particles together with organic materials was moved away from the study area. For the river-borne particles from the Gaoping river, a pair of depocenters in the upper slope flanking the Gaoping submarine canyon are the locations where the maximum TCorg accumulation rate were observed which hold up to 45% (0.016Mtyr-1) of the calculated accumulation found in the study region. On the other hand, the occurrence of higher-fraction terrestrial organic carbon in the upper and middle Gaoping submarine canyon suggests that a majority of particulate organic carbon of the Gaoping river was transported directly into the deep-sea basin through the Gaoping submarine canyon. Our results demonstrated that active margin with narrow shelf and slope is not an efficient sink for the large amount of terrigenous organic carbon supplied by the small rivers, but, a transient environment for these river derived particles. © 2014 Elsevier Ltd.

Arsenic is a potent human carcinogen of skin, lung, and urinary bladder. Freshwater clam Corbicula fluminea is a commercially important native species in Taiwan. C. fluminea is also a suitable biomonitoring test organism. Little is known, however, about the actual effects of arsenic on C. fluminea. The objectives of this study were to provide information on the acute toxicity and bioaccumulation kinetics of arsenic in C. fluminea. We carried out a 14-day exposure experiment to obtain bioaccumulation parameters. Uptake was very rapid when C. fluminea was first exposed and then slightly decayed during the uptake phase of the experiment and an uptake rate constant of 1.718 ± 6.70 (mean ± SE) mL g-1 d-1 was estimated. The elimination of arsenic from C. fluminea obeyed first-order depuration kinetics (r2 = 0.85, p < 0.05) with a calculated half-life of 6.80 days. The derived bioaccumulation factor of 16.84 suggests that arsenic has a high potential for bioaccumulation in C. fluminea. This had important implications for dietary exposure of arsenic to humans who eat contaminated clams, because the soft tissue usually constitutes the majority of tissue consumed. The 96-h LC50 value was estimated to be 20.74 (95% CI: 11.74-30.79) mg L-1 obtained from a 7-day acute toxicity bioassay. We also kinetically linked an acute toxicity model and a Hill sigmoid model to reconstruct an internal effect concentration based dose-response profile to assess the effect of soft tissue arsenic burden on the C. fluminea mortality. This result could be used to support the establishment of an ecological risk assessment to prevent possible ecosystem and human health consequences. © 2008 Wiley Periodicals, Inc.