Landscape-scale analysis of ecosystem risk and returns: A new tool for ICZM

Management of the coastal zone often focuses on “islands” of high value ecosystems, in terms of economic value or conservation. However, integrated management requires landscape-level analysis of all ecosystem values. The biodiversity portfolio analysis (BPA) method is derived from the logic used in share (equity) portfolio management in terms of balancing within a portfolio the returns with the risks. Optimising the returns from a share portfolio, or a suite of ecosystems in a landscape, is dependent on the relationship between the units in terms of risk and return. Three case studies are then presented to test the applicability of the BPA method at the international (North West Europe), regional (Durham Heritage Coast, UK) and local (part of South Uist, Outer Hebrides, UK) spatial scale. The Biodiversity Portfolio Analysis for NW Europe showed that risk and return were highly correlated in the studied Member States. The ranking of risk and return, with the highest first, was Ireland > UK > France=Netherlands > Belgium. For these Member States the risks to ecosystem service provision were positively correlated with GNI (r=0.97, P<0.01); suggesting that the higher the economic importance of coastal and marine resources in a Member State the more at risk the resources are. The regional and local case studies were more focussed on providing information on which to base Integrated Coastal Zone Management (ICZM) decision making; both case studies used stakeholder participation to determine risks and returns. The conclusions from these two case studies show how the BPA method can be useful in terms of setting ICZM priorities and in addressing local coastal issues. The BPA involves making a number of assumptions, however, it does provide coastal managers with a potential tool to strategically plan due to increased awareness of the interaction between the ecosystems in the portfolio.There is a need for such techniques, which involve stakeholder participation and which create objective outcomes, to support the implementation of ICZM.     

Dissolved organic matter variations in coastal plain wetland watersheds: The integrated role of hydrological connectivity,land use,and seasonality

Dissolved organic matter (DOM) is integral to fluvial biogeochemical functions, and wetlands are broadly recognized as substantial sources of aromatic DOM to fluvial networks. Yet how land use change alters biogeochemical connectivity of upland wetlands to streams remains unclear. We studied depressional geographically isolated wetlands on the Delmarva Peninsula (USA) that are seasonally connected to downstream perennial waters via temporary channels. Composition and quantity of DOM from 4 forested, 4 agricultural, and 4 restored wetlands were assessed. Twenty perennial streams with watersheds containing wetlands were also sampled for DOM during times when surface connections were present versus absent. Perennial watersheds had varying amounts of forested wetland (0.4–82%) and agricultural (1–89%) cover. DOM was analysed with ultraviolet–visible spectroscopy, fluorescence spectroscopy, dissolved organic carbon (DOC) concentration, and bioassays. Forested wetlands exported more DOM that was more aromatic‐rich compared with agricultural and restored wetlands. DOM from the latter two could not be distinguished suggesting limited recovery of restored wetlands; DOM from both was more protein‐like than forested wetland DOM. Perennial streams with the highest wetland watershed cover had the highest DOC levels during all seasons; however, in fall and winter when temporary streams connect forested wetlands to perennial channels, perennial DOC concentrations peaked, and composition was linked to forested wetlands. In summer, when temporary stream connections were dry, perennial DOC concentrations were the lowest and protein‐like DOM levels the highest. Overall, DOC levels in perennial streams were linked to total wetland land cover, but the timing of peak fluxes of DOM was driven by wetland connectivity to perennial streams. Bioassays showed that DOM linked to wetlands was less available for microbial use than protein‐like DOM linked to agricultural land use. Together, this evidence indicates that geographically isolated wetlands have a significant impact on downstream water quality and ecosystem function mediated by temporary stream surface connections.     

Development of a distributed hydrological model to facilitate watershed management

To facilitate precise and cost-effective watershed management, a simple yet spatially and temporally distributed hydrological model (DHM-WM) was developed. The DHM-WM is based on the Mishra-Singh version of the curve number method, with several modifications: The spatial distribution of soil moisture was considered in moisture updating; the travel time of surface runoff was calculated on a grid cell basis for routing; a simple tile flow module was included as an option. The DHM-WM was tested on a tile-drained agricultural watershed in Indiana, USA. The model with the tile flow module performed well in the study area, providing a balanced water budget and reasonable flow partitioning. The daily coefficient of determination and Nash-Sutcliffe coefficient were 0.58 and 0.56, for the calibration period, and 0.63 and 0.62 for the validation period. The DHM-WM also provides detailed information about the source areas of flow components, the travel time and pathways of surface runoff.

EDITOR A. Castellarin; ASSOCIATE EDITOR F.-J. Chang     

“Lessons for marine conservation planning: A comparison of three marine protected area planning processes”

Various approaches have been used to establish marine protected areas (MPAs) in different countries. In this paper we compare and review three processes to establish MPAs within the United States and Australia. These two countries share many similarities in their cultures, but their approaches to managing marine resources differ considerably. Each of these efforts to establish or review MPAs was motivated by concern about declines of targeted marine species or habitats. However, the government actions varied because of differences in governance, planning process including public input, and the role of science. Comparing these processes highlights effective approaches for protecting marine ecosystems and gaining public support.     

Submarine exhalative gold mineralization at the London-Virginia Mine,Buckingham County,Virginia

Low grade submarine exhalative gold mineralization occurs at the London-Virginia deposit in central Virginia Piedmont. The deposit consists of a series of localized but conformable units — basal garnetiferous-chlorite schist, magnetite schist, quartz-muscovite schist, ferruginous quartzite, and chlorite-biotite schist — which represent a mixture of submarine epiclastic volcanic debris and exhalative chemical sediments. Finely disseminated gold occurs dispersed with minor amounts of pyrite, sphalerite, chalcopyrite, galena, and tennantite in the ferruginous quartzite and quartz-muscovite schist. The deposit is believed to have formed by processes analogous to those currently active in the Atlantis II Deep of the Red Sea. Silicarich, hypersaline brines discharged through fractures in the sea floor and ponded in a local basin. Epiosodic influx of clastic debris and extensive deposition of hydrothermal silica diluted the concentration of sulfides and gold to produce a low-grade, siliceous mineralized zone. Emanation from the exhalative vent was terminated when the basin was capped by a lava flow. Subsequent regional greenschist grade metamorphism has recrystallized the silica into a granular quartzite and produced minor remobilization of the gold and sulfides.     

Robustness of variograms and conditioning of kriging matrices

Current ideas of robustness in geostatistics concentrate upon estimation of the experimental variogram. However, predictive algorithms can be very sensitive to small perturbations in data or in the variogram model as well. To quantify this notion of robustness, nearness of variogram models is defined. Closeness of two variogram models is reflected in the sensitivity of their corresponding kriging estimators. The condition number of kriging matrices is shown to play a central role. Various examples are given. The ideas are used to analyze more complex universal kriging systems.Research performed while on leave at Centre de Geóstatistique et de Morphologie Mathématique, Fontainebleau.