Effects of settlement density on spatial arrangement in four intertidal barnacles

Balanus amphitrite was studied in an estuary (Halifax River) in central Florida from October to November 1990, while three other barnacle species were studied on the central coast (Monterey Bay) of California from April 1988 to July 1989. Mean nearest-neighbor distances indicated that in the majority of cases the spatial arrangement of settlers was random for three different balanomorph barnacles-B. amphitrite, B. glandula, and Chthamalus dalli. In Pollicipes polymerus, a lepidomorph species, strong aggregation among settlers was almost always observed. In the three balanomorph species there was no apparent relationship between settler density and the degree of aggregation. In P. polymerus there was a significant positive correlation between settler density and the degree of aggregation. Morphological differences between balanomorph and lepidomorph barnacles may influence the evolution of settlement behavior.     

Recapturing fugitive power: epistemology, complexity and democracy

While policy network theory employs complexity concepts (self-regulation, emergence) mainly as explanatory tools, potential theoretical contributions arising from the underpinning analytical principles have been less explored. It is argued that by directly considering multi-level environmental governance as a far-from-equilibrium complex system, it is possible to explore how governance structures might better support and construe the dynamic and delicate conditions necessary for the presence of life. Problem formulation or 'agenda setting' powers exerted by civil servants and scientists are examined as emergent properties, systemic in and necessary for the stability of multi-level governance structures. Finally, it is proposed that multi-level environmental governance design may be improved through a reconceptualisation of representation, informed by principles from complexity theory, which embraces and 'recaptures' power exerted through extra-electoral governance relationships.     

Land poverty and emerging ruralities in Cambodia: insights from Kampot province

Rural change in Cambodia manifests itself in rapidly declining land availability for the smallholder sector, posing the question of how farmers may be able to deal with limited access to land. In this paper, we discuss with a case study village and household livelihood strategies of smallholders currently operating under land-constrained conditions. Based on an integrated assessment of a smallholder village in Kampot province, we illustrate in quantitative terms how land shortage is creating problems of surplus generation and liquidity issues in monetary and non-monetary flows. At the household level, livelihood diversification based on the involvement of productive resources other than land may play an increasing role, particularly in the future, when levels of land shortage may increase. At the village level, smallholder may respond through institutional innovation, in particular through the establishment of a community banking system and a paddy rice bank to provide money and rice credits to overcome transitory shortages and to cover investment costs for additional productive resources. Thus, in this case, we observe the emergence of new patterns of livelihood in rural areas, based on the integration of non-land-based economic activities and new institutional settings.     

Integrating energy and land-use planning: socio-metabolic profiles along the rural–urban continuum in Catalonia (Spain)

Abandoning fossil fuels and increasingly relying on low-density, land-intensive renewable energy will increase demand for land, affecting current global and regional rural–urban relationships. Over the past two decades, rural–urban relationships all over the world have witnessed unprecedented changes that have rendered their boundaries blurred and have lead to the emergence of “new ruralities.” In this paper, we analyze the current profiles of electricity generation and consumption in relation to sociodemographic variables related to the use of time and land across the territory of Catalonia, Spain. Through a clustering procedure based on multivariate statistical analysis, we found that electricity consumption is related to functional specialization in the roles undertaken by different types of municipalities in the urban system. Municipality types have distinctive metabolic profiles in different sectors depending on their industrial, services or residential role. Villages’ metabolism is influenced by urban sprawl and industrial specialization, reflecting current “new ruralities.” Segregation between work activity and residence increases both overall electricity consumption and its rate (per hour) and density (per hectare) of dissipation. A sustainable spatial organization of societal activities without the use of fossil fuels or nuclear energy would require huge structural and sociodemographic changes to reduce energy demand and adapt it to regionally available renewable energy.     

Migration of heavy metals in soil as influenced by compost amendments

Soils contaminated with heavy metals can pose a major risk to freshwaters and food chains. In this study, the success of organic and inorganic intervention strategies to alleviate toxicity in a highly acidic soil heavily contaminated with As, Cu, Pb, and Zn was evaluated over 112 d in a mesocosm trial. Amelioration of metal toxicity was assessed by measuring changes in soil solution chemistry, metal leaching, plant growth, and foliar metal accumulation. Either green waste- or MSW-derived composts increased plant yield and rooting depth, reduced plant metal uptake, and raised the pH and nutrient status of the soil. We conclude that composts are well suited for promoting the re-vegetation of contaminated sites; however, care must be taken to ensure that very short-term leaching pulses of heavy metals induced by compost amendment are not of sufficient magnitude to cause contamination of the wider environment.     

A survey of lakes in the Republic of Ireland: hydrochemical characteristics and acid sensitivity

In 1997, as part of a national program to determine and map critical loads, a lake survey was carried out in the Republic of Ireland. In total 200 lakes were sampled, which represents approximately 3.3% of the total lake population. The majority of lakes were situated in remote, high-altitude, acid-sensitive areas along the coastal margins of the country. Lake chemistry was dominated by marine inputs. Approximately 50% of the lakes had DOC > 5 mg L-1 due to the presence of organic soils in a large proportion of the catchments. Nonmarine sulfate concentrations were at background levels (< 20 mu eq L-1) in 50% of the lakes. Exceedance of critical load was observed in 7% of the sampled lakes (13 lakes). However, there are uncertainties in the critical load calculations due to the interference of sea salts and organic acids; accurate estimation under such conditions requires long-term lake and deposition chemistry.     

Horizon scanning for South African biodiversity: A need for social engagement as well as science

Ambio - A horizon scan was conducted to identify emerging and intensifying issues for biodiversity conservation in South Africa over the next 5–10&nbsp;years. South African biodiversity...