Biogeophysical Factors Research Articles

Mapping of Forest Fire Vulnerability Using Information Value Model in West Kalimantan Province

Mapping forest fires became one of the efforts to reduce the fire vulnerability. Spatial model development for fire vulnerability could employ a GIS-based information value model (IVM) that excels in predicting vulnerability by leveraging hotspot inventory data. However, this model remained relatively unexplored. This research aimed to develop a fire vulnerability model of peatland-dominated areas in West Kalimantan Province and identify biogeophysical factors that significantly influence fire vulnerability in the research area. The IVM employed hotspots, accessibility, land cover, distance to settlements, distance to rivers, soil types, peat types, and Normalized Difference Vegetation Index (NDVI) parameters. The results revealed that the medium hazard class dominated forest and land fire vulnerability in West Kalimantan Province (272,663 ha). In addition, the average annual hotspot intensity from 2012 to 2022 negatively correlated with annual rainfall. Factors such as the brackish water topogen peat type, podzolic-cambisol soil type, accessibility, shrub land cover, and NDVI collectively contributed to the high level of vulnerability.

Effects of Wetland Degradation on Community Livelihoods: A Case of Mabengere Wetland in Kisiita Sub County, Kakumiro District, Uganda

Wetlands in Uganda play vital ecological, economic, socio-cultural, scientific and recreational purposes and yet they are currently threatened by anthropogenic and bio geophysical factors. The current study was initiated to determine the drivers of wetland degradation; and to assess the benefits and costs as a result of wetland degradation, to members of the local community in Kakumiro district, Uganda. A cross sectional research design that involved the collection of both quantitative and qualitative data from three hundred and eighty-seven respondents was used. Data were collected using a questionnaire, Key informant interview guide from the key informants and observation check list. Key findings revealed that sand and clay mining, agricultural activities, gathering building materials were the key activities carried out, which significantly affected the wetlands at P<0.05. In addition, the activities carried out in the wetlands significantly improved the livelihoods of the people living around them at P<0.05. The water levels in the wetlands were reduced that led to shortage of portable water and the water for watering animals, and also led to outbreak of fires which contributed to a reduction in the wetland’s biodiversity. This was confirmed by the Chi-square test which revealed that degradation of wetlands contributed to the costs incurred by members of the local community at P<0.05. It was therefore recommended that alternative sources of energy and building materials be availed like planting of upland trees. Also, there should be awareness intensification to members of the local community about the values and uses of wetlands aimed at scaling down their degradation.

Analyzing spatial variability of drivers of coastal wetland loss in the northern Gulf of Mexico using Bayesian multi-level models

ABSTRACT A modeling framework that can quantify the impact of multiple potential drivers on coastal wetland loss while estimating its uncertainties is needed to better conserve and restore these valuable ecosystems. We developed a Bayesian multi-level modeling framework to predict the areal wetland loss in the northern Gulf of Mexico, driven by relative sea-level rise (RSLR), vegetation productivity, tidal range, wave height, and coastal slope. We further investigated how the impact of these site or local-scale biogeophysical factors on wetland loss differed by watershed unit. The results indicate the importance of accounting for watershed boundaries where the coastal wetlands are located when evaluating their loss. The effects of RSLR, wave height, and tidal range on wetland loss differed by watershed. Inclusion of streamflow and land use/land cover at the watershed scale did not improve model predictions while other relevant watershed-scale covariates, such as sediment availability, are not available. Based on the 95% credible intervals of the posteriors of the model coefficients, there were only five watersheds among the 14 studied where RSLR, wave height, or tidal range, showed positive or negative effects on coastal wetland loss. The results demonstrate the complexity of modeling wetland loss processes as no single dominant driver was identified for most of the watersheds. Furthermore, the need to account for multiple drivers simultaneously to ensure the effectiveness of costly wetland restoration projects clearly appears warranted when evaluating wetland loss processes over a broad spatial scale.

How well does random forest analysis model deforestation and forest fragmentation in the Brazilian Atlantic forest?

We assessed the value of applying random forest analysis (RF) to relating metrics of deforestation (DF) and forest fragmentation (FF) to socioeconomic (SE) and biogeophysical (BGP) factors, in the Brazilian Atlantic Forest of Minas Gerais, Brazil. A vegetation-monitoring project provided land cover maps, from which we derived DF and FF metrics. An ecologic-economical zoning project provided more than 300 SE and BGP factors. We used RF to identify relationships between these sets of variables and compared its performance in this task to that of a more traditional multiple linear regression approach. We found that RF modelled relatively-well variance in all metrics used (the rate of deforestation, the amount of forest and the density and isolation of forest patches), presenting a better performance when compared to the classical approach. RF also identified geographical location and topographic factors as being most closely associated with patterns of DF and FF metrics. Both analyses found factors associated with economic productivity, social institutions, accessibility and exploration to have little relationship with forest metrics. RF was better at explaining variations in rates of deforestation, remaining forest and patch patterns, than the multiple linear regression approach. We conclude that RF provides a promising methodology for elucidating the relationships between land use and cover changes and potential drivers.

Dietary flexibility in small carnivores: a case study on the endangered northern quoll, Dasyurus hallucatus

The endangered northern quoll (Dasyurus hallucatus) is a predatory marsupial with a wide and disjointed distribution across northern Australia. The disjunct Pilbara population occurs in a uniquely arid area, and faces different threatening processes to populations elsewhere. To better understand the ecology of this small carnivore, we undertook a dietary analysis of 498 scats collected across ∼100,000 km2. We calculated dietary composition and niche breadth and modeled these against biogeophysical factors (latitude, longitude, rainfall, elevation, and distance to coast) for 10 study landscapes. We also conducted pairwise comparisons of diet groups to evaluate regional dietary differences. Quolls were highly omnivorous, consuming at least 23 species of vertebrates (mammals, birds, reptiles, frogs), as well as arthropods, molluscs, fruit, and carrion. Diet varied widely across the region, with up to 3-fold differences in dietary niche breadth between study landscapes. We found few clear environmental drivers of the diet of D. hallucatus. The most frequently consumed food type was insects, but their occurrence in diets decreased as that of rodents and vegetation increased, indicating potential dietary preferences. The broad and variable diet of D. hallucatus indicates opportunism similar to that of other small carnivores. Given this broad dietary niche, conservation managers will need a priori knowledge of local prey abundance if they are to accurately predict the composition of D. hallucatus diets.

Flow routing in mangrove forests: A field study in Trang province, Thailand

Flow routing in mangrove forests has great implications for the transport and distribution of sediments and nutrients and hence for mangroves' development and persistence. Whereas previous studies were limited to the creeks, supposedly feeding the surrounding mangroves, this study demonstrates the contribution of biogeophysical impacts on flow routing through estuarine mangroves. We present the results of a field campaign covering three pristine mangrove sites in two estuaries in Trang province, Thailand. The sites range from a mangrove forest elevated above mean sea level with steep cliffs and incised by tidal creeks, to smoothly inclining mangroves fronted by extensive mudflats and showing a clear vegetation zonation starting below mean sea level. It is shown how flow routing through estuarine mangroves is impacted by biogeophysical factors; elevation, exposure and vegetation. Within the higher elevated mangroves, creek flow prevails when water levels remain below a dense vegetation layer at the mangrove fringe bordering the estuary. Sheet flow prevails when this threshold is exceeded and direct water exchange takes place. The low-lying sites do not feature creeks and tidal flows are typically sheet flows, being susceptible to forcing by river discharges. With decreasing water depths and/or increasing vegetation densities, the effects of this forcing are reduced and flow velocities follow the vegetation induced cross-shore water level gradients. Flow velocities within the creeks are up to an order of magnitude greater than those within the vegetation, where velocities decrease progressively with increasing vegetation densities. Particular vegetation and elevation characteristics cause irregular velocity variations along the vertical, within the vegetation as well as in the creeks. Tentative tidal flux calculations demonstrate the significant contribution of creek flow to the total tidal prism in higher elevated mangroves. By explicitly quantifying and mapping flow routing through mangrove forests, this study provides observational evidence for flow routing phenomena that have been postulated in previous studies.

Forest dynamics in Mississippi, USA: a hybrid statistical and geospatial analysis

Understanding forest changes and its trajectory is important to develop policy options and future scenarios for climate analysis. This research is conducted to gain insights on secondary forests change using Mississippi, USA, as a case study. We investigate the spatial patterns and temporal dynamics of secondary forests at high resolution and examine the forces driving their changes. An extensive literature review is conducted to refine the conceptual framework of forest changes and identify the underlying key factors. Forest changes are quantified at high spatial (30-m) and temporal (biennial) resolutions, using time series remotely sensed data between 1984 and 2007. A number of geospatial and socioeconomic data were compiled to analyze the spatial variations of forest disturbances and their linkages to various socioeconomic, political, and biogeophysical factors. The results show that the secondary forests are highly dynamic and variable. Disturbances and regeneration occur continuously everywhere in a systematic and coordinated fashion. This pattern prevents an extensive disturbance and increases total forest cover. Market conditions (i.e., timber price) are the key predictor of the level and overall trend of forest disturbances. However, spatial patterns of forest dynamics cannot be explained by location-specific biophysical, socioeconomic, and policy factors identified in the literature. They can best be described by the ecological characteristics of the forests (i.e., the forest type and age distribution), which have a clear economic linkage. The research shows that regenerated forests frequently experience loss and gain of their extent, and their ecological characteristics change drastically on a short-term basis. These results point out challenges and opportunities in forest management and policy with regard to reforestation.

In situ flume measurements of resuspension in the North Sea

The in situ annular flume, Voyager II, was deployed at three sites in the North Sea in order to investigate resuspension events, to determine the physical characteristics of the seabed, to determine the threshold of resuspension of the bed and to quantify erosion rates and erosion depths. These are the first controlled, in situ flume experiments to study resuspension in the North Sea, and were combined with long-term measurements of waves and currents. Resuspension experiments were undertaken at two muddy, and one sandy site: north of the Dogger Bank (DG: water depths ∼80 m, very fine, poorly sorted, very fine-skewed sediment experiencing seasonal thermal stratification of the water column along with oxygen depletion); the Oyster Grounds (OG: ∼40 m, similar bed properties, year round water column thermal stratification, Atlantic forcing); and in the Sean Gas Field (SGF: ∼20 m, moderately sorted, very coarse-skewed sand, and well mixed water column). The erosion thresholds of the bed were found to be 0.66–1.04 Pa (DG) and 0.91–1.27 Pa (OG), with corresponding erosion depths of 0.1–0.15 mm and 0.02–0.06 mm throughout the experiments. Evaluation of a year of current velocities from 2007 indicated that at OG, resuspension of the consolidated bed was limited to on average ∼8% of the time as a result of tidal forcing alone for short (<30 min) durations, but would potentially increase during the winter as a result of wave influences. At DG, under similar conditions this would increase to 13%, and in the SGF, wave-induced resuspension events occurred throughout the year, with the potential exceedance of the threshold for suspension greater than 50% in January and March. Resuspension of bed material and erosion rates were closely related to applied bed shear stresses, and eroded depths were significantly correlated with the physical properties of the bed. Therefore, while complex variations in biogeophysical factors affected the critical threshold of erosion, once exceeded, erosion rates were related to the nature of the sediment.

Preface to special section on Past and Future Trends in Nutrient Export From Global Watersheds and Impacts on Water Quality and Eutrophication

[1] Coastal eutrophication is a worldwide problem [Diaz and Rosenberg, 2008; Selman et al., 2008]. It is largely caused by increased river transport of nutrients such as nitrogen (N), phosphorus (P), and carbon (C). Further distortion of coastal marine ecosystems is related to changing element ratios as a result of increasing N and P loading and decreasing river export of silica (Si). The main causes of increased river nutrient loading are the increasing livestock and crop production and fertilizer use, and increasing wastewater flows. There have been considerable gains in knowledge of current amounts and sources of N and P entering the terrestrial biosphere, and biogeophysical factors that control the amount of N and P ultimately exported by rivers to coastal ecosystems. Considerably less work has addressed how various socioeconomic factors and approaches to nutrient management affect N and P inputs to the terrestrial biosphere and subsequent impacts on river nutrient export. [2] This special section of Global Biogeochemical Cycles focuses on Past and Future Trends in Nutrient Export from Global Watersheds and Impacts on Water Quality and Eutrophication. It summarizes the recent work of the Global Nutrient Export fromWatersheds (NEWS) work group, using an integrated modeling approach connecting socioeconomic, nutrient management and biogeophysical factors to river export. [3] We present the second generation of the Global NEWS model [Mayorga et al., 2010; Seitzinger et al., 2010]. The first generation of the NEWS model was published in a 2005 Special Section of Global Biogeochemical Cycles [Beusen et al., 2005; Dumont et al., 2005; Harrison et al., 2005a; Harrison et al., 2005b; Seitzinger et al., 2005]. The NEWS model calculates river export of different forms of N, P, C and Si as a function of hydrology, morphology, land use and human activities in the river basin. More than 6000 river basins are included in the model. [4] Since 2005, three important developments took place on which we report in this special section: (1) several submodels for individual nutrient forms were updated [Beusen et al., 2009; Harrison et al., 2010; Mayorga et al., 2010; Seitzinger et al., 2010], such as including detergent sources of P in the DIP submodel [Harrison et al. 2010], and development of a submodel for river export of dissolved silica [Beusen et al., 2009]; (2) the models for different nutrient species were integrated into one modeling interface [Mayorga et al., 2010]; and (3) the model was used to analyze past trends (1970–2000) and four future scenarios (up to 2050). The future scenarios were based on the Millennium Ecosystem Assessment (MEA) [Alcamo et al., 2006]. We interpreted these scenarios to develop spatially explicit model inputs for diffuse sources of nutrients from agriculture and natural ecosystems [Bouwman et al., 2009] and sewage [Van Drecht et al., 2009], and hydrology [Fekete et al., 2010] consistent with the range of social, economic, policy, and ecological considerations in the four MEA scenarios. [5] Past and future trends in river nutrient export to coastal waters calculated from the NEWS model were used to analyze global trends [Seitzinger et al., 2010] as well as changes at the continental scale for South America andAfrica [van der Struijk and Kroeze, 2010; Yasin et al., 2010] or at the scale of individual river basins in Europe [Thieu et al., 2010; Yan et al., 2010], and a time series comparison of measured and modeled DIN export by the Changjiang River (1970–2003) [Yan et al., 2010]. We also developed a global perspective on indicators for nutrient inputs to land, and for changing nutrient ratios which could favor increases in nondiatom algal blooms [Billen et al., 2010; Garnier et al., 2010]. [6] Our results indicate that since 1970, river export of nutrients has been increasing considerably in many world regions. During the coming decades, DIN andDIP loads were projected to continue to increase in many world regions; however, particulate loads were projected to decrease. Perhaps the most surprising result of our analyses was that for large world areas, at least in one scenario, we calculate lower nutrient export rates in the future than in 2000, despite inInstitute of Marine and Coastal Sciences, Rutgers University, Rutgers/NOAA CMER Program, New Brunswick, New Jersey, USA. Netherlands Environmental Assessment Agency, Bilthoven, Netherlands. Environmental Systems Analysis Group, Wageningen University, Wageningen, Netherlands. School of Science, Open University of Netherlands, Heerlen, Netherlands.

Facilitating Climate Justice through Community-Based Adaptation in the Health Sector

Abstract Climate change presents real risks to human health, with the impacts unevenly distributed because of biogeophysical factors and population vulnerabilities. Although everyone is at some level susceptible to the health consequences of changing weather patterns and alterations in the geographic distribution and incidence of climate-sensitive health outcomes, there are populations and geographic regions that have enhanced vulnerability. Low-income communities and communities of color are disproportionately represented in vulnerable groups, which include the elderly, pregnant women and children, those with chronic medical conditions, people with mobility and cognitive constraints, and the urban and rural poor. Public health interventions designed and deployed in conjunction with these groups and other relevant stakeholders increases individual and community acceptance of, and the success of, the intervention, along with reducing constraints to implementation. Community-based adaptations that address t...

Implications of wetlands degradation for water resources management: Lessons from Nigeria

Nigeria is a country richly endowed with both coastal and inland wetlands, which altogether cover about 3% of the country's land surface. These wetlands are of ecological, economic, socio-cultural, scientific and recreational significance. Nevertheless, Nigeria's wetland resources are currently being threatened by certain anthropogenic and biogeophysical factors. Notable among such factors are population pressure, rapid rate of urbanization, mining, oil and industrial waste pollution, uncontrolled tilling for crop production, over-grazing, logging, unprecedented land reclamation, construction of dams, transportation routes and other physical infrastructure, marine and coastal erosion, subsidence, ocean water intrusion, invasion by alien floral and faunal species, sand storm, desertification, and droughts. The alarming rate at which the country's wetlands are vanishing obviously portends some dire consequences. In particular, wetlands destruction is affecting water supply and water resources management in various parts of the country. Wetlands perform some vitally important hydrological functions in the country. For instance, apart from being quite instrumental to flood protection, wetlands equally maintain stream flow during the dry season in the semi-arid region of northern Nigeria. Importantly, they also help in regulating surface water quality and volume, as well as in replenishing and sustaining groundwater. There is no gainsaying, therefore, that the degradation of wetland ecosystems in Nigeria increases the task of water resources management in the country. Thus, the country's wetland resources need to be properly identified and mapped. Moreover, the right legislation and policy framework has to be put in place and enforced to safeguard the remaining wetlands from the ongoing wanton destruction.

Biogeophysical factors influencing soil respiration and mineral nitrogen content in an old field soil

Microbivorous grazers are thought to enhance nutrient mineralization. The predicted effect of microbivory on nutrient cycling depends on the pore habitat model used. We evaluated CO 2 evolution and mineral N content of an old field soil to test two alternative habitat hypotheses. The exclusion hypothesis predicts that nematodes are separated from their microbial food resources in water-filled pores when soils dry, resulting in slower rates of biogeochemical transformations. The enclosure hypothesis predicts that nematode densities increase relative to their forage in smaller, isolated water volumes when soils dry, accelerating rates of biogeochemical transformations. We investigated the effect of soil moisture on the relationship between microbial biomass, microbivorous and predaceous nematodes, soil respiration and mineral N concentrations in an old field five times during the course of a year. We could evaluate the validity of the two habitat hypotheses for the entire field only in August 1997 because that was the only sampling date when maximum water-filled pore diameters were smaller than microbivorous nematode body diameters in all sampled field locations. The mean microbivorous and predaceous nematode abundances for the field in August were greater than 6300 kg −1 and 80,000 kg −1, respectively. Accordingly, the exclusion hypothesis was rejected. Predaceous nematode abundance was markedly higher in August than at any other sampling date. The high abundance of predators present suggests that detrital resources were not limiting productivity and that predators and microbivores were in enclosures, allowing predators to efficiently access their prey. Spatial maps, in agreement with linear correlation analyses, suggest that under our driest sampling conditions, soil respiration and mineral N content were controlled by microbivory and predation.

Nutrition, management and other environmental influences on the quality and production of mohair and cashmere: A review with particular reference to mediterranean and annual temperate climatic zones

Goat fibre production is affected by genetic and environmental influences. Environmental influences which are the subject of this review include bio–geophysical factors (photoperiod, climate–herbage system and soil–plant trace nutrient composition), nutrition factors and management factors. Nutrition and management influences discussed include rate of stocking, supplementary feeding of energy and protein, liveweight change, parturition and management during shearing. While experimental data suggest affects of seasonal photoperiod on the growth of mohair and cashmere are large, these results may have confounded changes in temperature with photoperiod. The nutritional variation within and among years is the most important climatic factor influencing mohair and cashmere production and quality. Mohair quality and growth is affected significantly by rate of stocking and during periods of liveweight loss by supplementary feeding of either energy or protein. Strategic use of supplements, methods for rapid introduction of cereal grains, influence of dietary roughage on intake and the economics of supplementary feeding are discussed. Cashmere production of young, low producing goats does not appear to be affected by energy supplementation, but large responses to energy supplementation have been measured in more productive cashmere goat strains. The designs of these cashmere nutrition experiments are reviewed. Evidence for the hypothesis that energy-deprived cashmere goats divert nutrients preferentially to cashmere growth is reviewed. The influence and potential use of liveweight manipulation in affecting mohair and cashmere production and quality are described. Estimates of the energy requirements for the maintenance of fibre goats and the effect of pregnancy and lactation on mohair and cashmere growth are summarised. The effects and importance of management and hygiene during fibre harvesting (shearing) in producing quality fibre is emphasised. The review concludes that it is important to assess the results of scientific experiments for the total environmental content within which they were conducted. The review supports the view that scientific experiments should use control treatments appropriate to the environment under study as well as having controls relevant for other environments. In mediterranean and annual temperate environments, appropriate controls are liveweight loss and liveweight maintenance treatments. Mohair producers must graze goats at moderate rates of stocking to maximise animal welfare, but in so doing, they will produce heavier goats and coarser mohair. In mediterranean and annual temperate environments, seasonal changes in liveweight are large and influence both quality and production of mohair and cashmere. Mohair and cashmere producers can manipulate liveweight by supplementary feeding energy during dry seasons to minimise liveweight loss, but the economics of such feeding needs to be carefully examined. Strategic benefits can be obtained by enhancing the growth of young does prior to mating and for higher producing cashmere goats.