Exploring management strategies for community-based forests using multi-agent systems: A case study in Palawan, Philippines

This paper describes the experiences and lessons learned in applying a multi-agent systems (MAS) model to study the dynamics and complex interactions among stakeholders in the management of community-based forests. The MAS model is developed using the companion modelling (ComMod) approach, which allows for a collaborative development of the model between the stakeholders and researchers. This approach involves the development and application of role-playing games (RPGs) and computer simulation as learning tools and to validate the model. Inferences are drawn from the learning and negotiation processes that the stakeholders and researchers underwent in the collaborative development of the MAS model. These processes ultimately led to the development of a collaborative resource management plan. The approach and the MAS model were applied to a case study involving a community-based forest managed by three villages in the island of Palawan, Philippines.     

Photocatalytic elimination of indoor air biological and chemical pollution in realistic conditions

The photocatalytic elimination of microorganisms from indoor air in realistic conditions and the feasibility of simultaneous elimination of chemical contaminants have been studied at laboratory scale. Transparent polymeric monoliths have been coated with sol-gel TiO(2) films and used as photocatalyst to treat real indoor air in a laboratory-scale single-step annular photocatalytic reactor. The analytical techniques used to characterize the air quality and analyze the results of the photocatalytic tests were: colony counting, microscopy and PCR with subsequent sequencing for microbial quantification and identification; automated thermal desorption coupled to gas chromatography with mass spectrometry detection for chemical analysis. The first experiments performed proved that photocatalysis based on UVA-irradiated TiO(2) for the reduction of the concentration of bacteria in the air could compete with the conventional photolytic treatment with UVC radiation, more expensive and hazardous. Simultaneously to the disinfection, the concentration of volatile organic compounds was greatly reduced, which adds value to this technology for real applications. The fungal colony number was not apparently modified.     

Endosulfan acute toxicity and histomorphological alterations in Jenynsia multidentata (Anablepidae, Cyprinodontiformes)

Toxicity tests using adult specimens of Jenynsia multidentata were carried out during 96 hours in order to determine the lethal concentration (LC50) of endosulfan. Histological alterations were determined in gills and liver. Gill damage was quantified as secondary lamellae thickness. The 96 hr LC50 values were significantly different between males (0.719 microg x L(-1)) and females (1.317 microg x L(-1)). The sex difference was attributed to the dimorphism in the lipid content in females (2.16%) and males (1.79%). Histological alterations in gills included hypertrophy and lifting of the epithelium of the secondary lamellae and aneurisms. These alterations caused a significant increase of the secondary lamellae thickness in treatment versus control fish. Finally, reversible histological alterations (such as hydropic degeneration and dilation of sinusoids) were observed in the liver of exposed fish as well as an irreversible change such as necrosis at the highest concentrations.     

Simultaneous measurements of formaldehyde and nitrous acid in dews and gas phase in the atmosphere of Santiago,Chile

The amounts of formaldehyde and nitrous acid (HONO) in gas phase and dews of Santiago de Chile were simultaneously measured. Formaldehyde concentrations values in the liquid phase (dews) correlate fairly well with those in the gaseous phase and are even higher than those expected from gas–dew equilibrium. On the other hand, nitrite concentrations in dews were considerably smaller (ca. 15 times) than those expected from the gas-phase concentrations. This under-saturation is attributed to diffusion limitations due to the relatively large HONO solubility. In agreement with this, under-saturation increases with the rate of dew formation and the pH of the collected waters, factors that should increase the rate of gas to liquid HONO transfer required to reach equilibrium.     

Performances and application of a passive sampling method for the simultaneous determination of nitrogen dioxide and sulfur dioxide in ambient air

The performances and applicability of a diffusion tubesampler for the simultaneous measurements of NO₂ andSO₂ in ambient air were evaluated. SO₂ andNO₂are collected by the passive sampler using triethanolamine astrapping agent and are determined as sulphate and nitrite withion chromatography. The detection limit (2.3 g m^-3 ofNO₂ and 4.2 g m^-3 of SO₂ for two weekssampling) is adequate for the determination of concentrationsin urban and industrial areas. Precision of the method as RSDis in mean 5% for NO₂ and 12% for SO₂ at theconcentration levels in urban areas. Calibration of the methodwas performed in the field conditions by comparison between theresponses of sampler and the concentrations measured by thecontinuous monitors. High degree of linearity (correlationcoefficients > 0.8) is found between the passive sampler tubeand the continuous monitor data for both NO₂ and SO₂.To reduce the wind velocity influence on passive sampling ofdiffusion tubes, a protective shelter was tested in this study.The overall uncertainty of one measure for the optimised methodis estimated at 5 g m^-3 for NO₂ and 6g m^-3 for SO₂. Suitability of this passivesampling method for air pollution monitoring in urban areas wasdemonstrated by the results shown in this paper on a campaigncarried out in the French agglomeration.     

Ecology of hemiepiphytism in fig species is based on evolutionary correlation of hydraulics and carbon economy

Woody hemiepiphytic species (Hs) are important components of tropical rain forests, and they have been hypothesized to differ from non-hemiepiphytic tree species (NHs) in adaptations relating to water relations and carbon economy; but few studies have been conducted comparing ecophysiological traits between the two growth forms especially in an evolutionary context. Using common-garden plants of the genus Ficus, functional traits related to plant hydraulics and carbon economy were compared for seven NHs and seven Hs in their adult terrestrial "tree-like" growth phase. We used phylogenetically independent contrasts to test the hypothesis that differences in water availability selected for contrasting suites of traits in Hs and NHs, driving evolutionary correlations among functional traits including hydraulic conductivity and photosynthetic traits. Species of the two growth forms differed in functional traits; Hs had substantially lower xylem hydraulic conductivity and stomatal conductance, and higher instantaneous photosynthetic water use efficiency. Leaf morphological and structural traits also differed strikingly between the two growth forms. The Hs had significantly smaller leaves, higher leaf mass per area (LMA), and smaller xylem vessel lumen diameters. Across all the species, hydraulic conductivity was positively correlated with leaf gas exchange indicating high degrees of hydraulic-photosynthetic coordination. More importantly, these correlations were supported by correlations implemented on phylogenetic independent contrasts, suggesting that most trait correlations arose through repeated convergent evolution rather than as a result of chance events in the deep nodes of the lineage. Vatiation in xylem hydraulic conductivity was also centrally associated with a suite of other functional traits related to carbon economy and growth, such as LMA, water use efficiency, leaf nutrient concentration, and photosynthetic nutrient use efficiency, indicating important physiological constraints or trade-offs among functional traits. Shifts in this trait cluster apparently related to the adaptation to drought-prone canopy growth during the early life cycle of Hs and clearly affected ecophysiology of the later terrestrial stage of these species. Evolutionary flexibility in hydraulics and associated traits might be one basis for the hyper-diversification of Ficus species in tropical rain forests.     

An agent based model to simulate structural and land use changes in agricultural systems of the argentine pampas

The Argentine Pampas, one of the main agricultural areas in the world, recently has undergone significant changes in land use and structural characteristics of agricultural production systems. Concerns about the environmental and societal impacts of the changes motivated development of an agent-based model (ABM) to gain insight on processes underlying recent observed patterns. The model is described following a standard protocol (ODD). Results are discussed for an initial set of simplified simulations performed to understand the processes that generated and magnified the changes in the Pampas. Changes in the structure of agricultural production and land tenure seem to be driven by differences among farmers’ ability to generate sufficient agricultural income to remain in business. In turn, as no off-farm or credit is modeled, economic sustainability is tied to initial resource endowment (area cropped). Farmers operating small areas are economically unviable and must lease out their farms to farmers operating larger areas. This leads to two patterns: (a) a concentration of production (fewer farmers operating larger areas) and, (b) an increase in the area operated by tenants. The simulations showed an increase of soybean area, linked to the higher profitability of this crop. Despite the stylized nature of initial simulations, all emerging patterns are highly consistent with changes observed in the Pampas.     

An unforgettable event: a qualitative study of the 1997–98 El Niño in northern Peru

During the 1997–98 El Niño, Tumbes, Peru received 16 times the annual average rainfall. This study explores how Tumbes residents perceived the impact of the El Niño event on basic necessities, transport, health care, jobs and migration. Forty‐five individuals from five rural communities, some of which were isolated from the rest of Tumbes during the event, participated in five focus groups; six of these individuals constructed nutrition diaries. When asked about events in the past 20 years, participants identified the 1997–98 El Niño as a major negative event. The El Niño disaster situation induced a decrease in access to transport and health care and the rise in infectious diseases was swiftly contained. Residents needed more time to rebuild housing; recover agriculture, livestock and income stability; and return to eating sufficient animal protein. Although large‐scale assistance minimized effects of the disaster, residents needed more support. Residents' perspectives on their risk of flooding should be considered in generating effective assistance policies and programmes.