Downscaling scenarios of future land use and land cover changes using a participatory approach: an application to mountain risk assessment in the Pyrenees (France)

Regional Environmental Change - Better understanding the pathways through which future socioeconomic changes might influence land use and land cover changes (LULCCs) is a crucial step in accurately...     

Measurement of nest cavity volume by the honey bee (Apis mellifera)

Behavioral Ecology and Sociobiology -     

Long-term land-cover/use change in a traditional farming landscape in Romania inferred from pollen data,historical maps and satellite images

Regional Environmental Change - Traditional farming landscapes in the temperate zone that have persisted for millennia can be exceptionally species-rich and are therefore key conservation targets....     

Components of the Total Water Balance of an Urban Catchment

A daily model was used to quantify the components of the total urban water balance of the Curtin catchment, Canberra, Australia. For this catchment, the mean annual rainfall was found to be three times greater than imported potable water, and the sum of the output from the separate stormwater and wastewater systems exceeded the input of imported potable water by some 50%. Seasonal and annual variations in climate exert a very strong influence over the relative magnitude of the water balance components; this needs to be accounted for when assessing the potential for utilizing stormwater and wastewater within an urban catchment.     

Effects of static vs. tidal hydrology on pollutant transformation in wetland sediments

This work addressed effects of hydrology on biogeochemical processes relevant to pollutant chemical transformation in wetland sediments. Microcosms were designed to impose three hydrologic conditions on salt marsh sediments: (i) drained-oxidized redox potenial (Eh); (ii) flooded-reduced Eh and, (iii) diurnal tide-oscillating Eh. The test chemicals were N- and/or S-heterocycles (NSHs) including quinoxaline (1,4-benzodiazine), 2-methylquinoxaline(2-methyl-1,4-benzodiazine), 2,3-dimethylquinoxalinen (2,3-dimethyl-1,4-benzodiazine), phenazine (2,3,5,6-dibenzo-1,4-diazine), acridine (2,3,5,6-dibenzopyridine), dibenzothiophene (2,3,5-dibenzothiophene), phenothiazine (dibenzo-1,4-thiazine), and phenanthridine (2,3-benzoisoquinoline). Biogeochemical processes reflected the hydrologic conditions in ways analogous to field settings, e.g., Eh characteristics were drastically different: static (flooded and drained) systems had reduced (mu = -428 mV +/- 57) and oxidized (mu = +73 mV +/- 32) values, respectively, with no evidence of periodic variation while the tidal systems exhibited regularly oscillating Eh (amplitudes 40-250 mV). Sediment trace gases also corresponded to the Eh, with the major species detected being CO2 and H2O (drained, tidal) vs. CO2 + H2O + sulfides + methane (flooded). The NSH transformation rates were different in each hydrologic regime and decreased as follows: tidal > or = drained > flooded. These results indicated that there were subtle differences in NSH processing in drained and tidal systems, but both of these systems transformed NSHs faster and to lower levels than flooded sediments. These data suggest that in situ remediation options that preserve wetland integrity and tidal hydrology can be as or more effective than static conditions that obtain in approaches such as impoundment and excavation-upland placement.     

Preparing for ISO 14000: An assessment guide

With ISO 14000 expected to roll out in 1996, have you begun to evaluate how well your current environmental management policy, programs, procedures, and objectives conform to published national and evolving global Environmental Management System (EMS) standards?. The ISO expects to adopt a final standard by mid-1996 which specifies requirements for an EMS (e.g., ISO 14001). In addition, national EMS standards have already been developed and published by organizations such as The British Standards Institute and, in the United States, NSF International, for example, BS 7750 and NSF 110–1995, respectively. This article shows how managers can begin assessing their operations to prepare for these new standards and improve overall environmental performance.     

Modeling the Effects of Potential Salinity Shifts on the Recovery of Striped Bass in the Savannah River Estuary,Georgia–South Carolina,United States

Increased salinity in spawning and nursery grounds in the Savannah River estuary was cited as the primary cause of a 97% decrease in adult striped bass (Morone saxatilis) and a concomitant 96% decrease in striped bass egg production. Restoration efforts focused on environmental remediation and stock enhancement have resulted in restored salinity patterns and increased egg and adult abundances. However, future water needs or harbor development may preclude further recovery by reducing freshwater inflow or increasing salinity intrusion. To assess the effect of potential changes in the salinity regime, we developed models relating discharge, tidal phase, and salinity to striped bass egg and early larval survival and re-cast these in a quantitative Bayesian belief network. The model indicated that a small upstream shift (≤1.67 km) in the salinity regime would have the least impact on striped bass early life history survival, whereas shifts >1.67 km would have progressively larger impacts, with a 8.33-km shift potentially reducing our estimated survival probability by >28%. Such an impact could have cumulative and long-term detrimental effects on the recovery of the Savannah River striped bass population. The available salinity data were collected during average and low flows, so our model represents some typical and some extreme conditions during a striped bass spawning season. Our model is a relatively simplistic, “first-order” attempt at evaluating potential effects of changes in the Savannah River estuarine salinity regime and points to areas of concern and potential future research.     

ARE SOILS LIKE SPONGES?1

ABSTRACT: The purpose of this paper is to explore the validity of the old analogy that “soil is like a sponge.” Laboratory experiments were conducted to measure two hydrologic properties of porous media: drainage under gravity, and water potential curves. A tipping bucket rain gage connected to a data logger was used to measure the rate at which water drained under the force of gravity from a trough filled with four saturated porous media ‐ cellulose sponges, topsoil, peat, and a medium sand. Pressure plate techniques were used to determine water potential curves for soil materials and sponges. In terms of relative cumulative discharge from the trough, sponges were intermediate between peat and topsoil. Because of their tremendous water‐holding capacity, sponges discharged more than 2.5 times as much water as did peat. The water potential curve for sponges was fairly flat, like that of topsoil, but the high water content across all pressures (0.30–15.0 bars) indicated some similarity to peat. The results of these experiments suggest that the general patterns of water retention and release in soil materials and sponges are similar and vary only in degree.     

TEN YEARS OF VEGETATION SUCCESSION ON A DEBRIS‐FLOW DEPOSIT IN OREGON1

ABSTRACT: We tracked vegetation succession on a debris‐flow deposit in Oregon's Coast Range to examine factors influencing the development of riparian plant communities following disturbance. Plots were stratified across five areas of the deposit (bank slump, seep, upper and lower sediment wedge, log jam) the first growing season after debris flow. At six times during the next ten years we estimated cover of vascular plants and tallied density of woody plants. Plant colonization occurred within two years. Total cover increased two‐to seven‐fold on the five areas within three years. Red alder and salmonberry were the dominant species, although weedy herbs persisted where woody species were lacking. Ordination of cover data showed that the five areas remained floristically distinct over time, while undergoing similar shifts related to the increasing dominance of alder and salmonberry. Rapid height growth of alder allowed it to outcompete salmonberry and effectively capture most areas by the tenth year, even where sprouts from transported rhizomes gave salmonberry an early advantage. Our results suggest that successional patterns were influenced by substrate variability, species composition of initial colonizers, propagule sources and their distribution, and species life‐history traits such as growth rate, competitive ability, and shade tolerance.