Setting conservation priorities for migratory networks under uncertainty

Conserving migratory species requires protecting connected habitat along the pathways they travel. Despite recent improvements in tracking animal movements, migratory connectivity remains poorly resolved at a population level for the vast majority of species, thus conservation prioritization is hampered. To address this data limitation, we developed a novel approach to spatial prioritization based on a model of potential connectivity derived from empirical data on species abundance and distance traveled between sites during migration. We applied the approach to migratory shorebirds of the East Asian‐Australasian Flyway. Conservation strategies that prioritized sites based on connectivity and abundance metrics together maintained larger populations of birds than strategies that prioritized sites based only on abundance metrics. The conservation value of a site therefore depended on both its capacity to support migratory animals and its position within the migratory pathway; the loss of crucial sites led to partial or total population collapse. We suggest that conservation approaches that prioritize sites supporting large populations of migrants should, where possible, also include data on the spatial arrangement of sites.     

Case Studies of Minimizing Plating Bath Wastes in the Electronics Products Industry

In this paper the authors report on the results of case studies carried out under the sponsorship of the U.S. EPA to determine the effectiveness of four processes designed to reduce the amount of hazardous waste from plating operations. Data reported are based on the results of actual on-site sampling of the processes and encompass effectiveness, environmental, and economic considerations. Two of the case studies evaluating the use of sodium borohydride reduction as a substitute for lime/ferrous sulfate precipitation, found that the technology was a viable substitute in one case and was marginally acceptable in another. Another case study, involving carbon adsorption removal of organic contaminants from plating bath wastes, found that this technology significantly reduced both disposal costs and waste volume. A final case study of electrolytic recovery indicated that while acid copper electroplating rinses are amenable to electrolytic recovery, other metal-bearing rinses, such as those from solder (tin/lead) plating or etching are less appropriate.     

The role of habitat disturbance and recovery in metapopulation persistence

Classical metapopulation theory assumes a static landscape. However, empirical evidence indicates many metapopulations are driven by habitat succession and disturbance. We develop a stochastic metapopulation model, incorporating habitat disturbance and recovery, coupled with patch colonization and extinction, to investigate the effect of habitat dynamics on persistence. We discover that habitat dynamics play a fundamental role in metapopulation dynamics. The mean number of suitable habitat patches is not adequate for characterizing the dynamics of the metapopulation. For a fixed mean number of suitable patches, we discover that the details of how disturbance affects patches and how patches recover influences metapopulation dynamics in a fundamental way. Moreover, metapopulation persistence is dependent not only on the average lifetime of a patch, but also on the variance in patch lifetime and the synchrony in patch dynamics that results from disturbance. Finally, there is an interaction between the habitat and metapopulation dynamics, for instance declining metapopulations react differently to habitat dynamics than expanding metapopulations. We close, emphasizing the importance of using performance measures appropriate to stochastic systems when evaluating their behavior, such as the probability distribution of the state of the metapopulation, conditional on it being extant (i.e., the quasistationary distribution).     

AN OVERVIEW OF POROUS PAVEMENT RESEARCH1

ABSTRACT: This paper discusses the economics, advantages, potential applications, and status and future research needs of porous pavements. Porous pavements are an available storm water management technique which can be used on parking lots and low volume roadways in order to reduce both storm water runoff volume and pollution. In addition, ground water recharge is enhanced. Also, cost reductions result due to elimination of curbs, drains, and small sized storm sewers. Porous asphalt pavements consist of a relatively thin course of open graded asphalt mix over a deep base of large size crushed stones. Water can be stored in the crushed stone base until it can percolate into the subbase or drain laterally. Other porous pavement types include concrete lattice blocks and a porous concrete mix.     

COOPERATION IN WATER RESOURCES PROGRAMS: ALASKA'S EXAMPLE1

ABSTRACT: Alaska possesses a diversity and magnitude of water resources unmatched in any other state. With over 15% of the area of the whole United States, and 40% of the nation's total fresh water supply, but an extreme lack of basic hydrologic and climatologic data, cooperation among agencies and individuals concerned with evaluating, planning, and carrying out water resources programs is essential. Toward this end, the Inter-Agency Technical Committee for Alaska (IATCA) was established under charter from the Water Resources Council. Representation in IATCA includes virtually all Federal, State, and academic entities in Alaska having an interest in the water resources of the State. Existence of IATCA has permitted or facilitated numerous Alaskan water resources programs. Several are described briefly in this paper: A flood warning network in the Chena River basin; establishment of the Caribou-Poker Creeks Research Watershed in Central Alaska; preparation and periodic updating of the “Ten-Year Plan for Water Resources Data Acquisition”; current planning for an integrated “real-time reporting network” for hydrometeorological data within the State; and a framework for implementation of the Alaskan phase of the National Water Resources Assessment, currently in the initial phases. Accomplishments to date testify that it is indeed possible to “get it all together” in the broad field of “Water Resources” in the largest of our 50 states.     

Phosphorus removal in vegetated filter strips

Vegetated filter strips (VFS) are used recently for removal, at or near the source, of sediment and sediment-bound chemicals from cropland runoff. Vegetation within the flowpath increases water infiltration and decreases water turbulence, thus enhancing pollutant removal by sedimentation within filter media and infiltration through the filter surface. Field experiments have been conducted to examine the efficiency of vegetated filter strips for phosphorus removal from cropland runoff with 20 filters with varying length (2 to 15 m), slope (2.3 and 5%), and vegetated cover, including bare-soil plots as control. Artificial runoff used in this study had an average phosphorus concentration of 2.37 mg L(-1) and a sediment concentration of 2700 mg L(-1). The average phosphorus trapping efficiency of all vegetated filters was 61% and ranged from 31% in a 2-m filter to 89% in a 15-m filter. Filter length has been found to be the predominant factor affecting P trapping in VFS. The rate of inflow, type of vegetation, and density of vegetation coverage had secondary influences on P removal. Short filters (2 and 5 m), which are somewhat effective in sediment removal, are much less effective in P removal. Increasing the filter length beyond 15 m is ineffective in enhancing sediment removal but is expected to further enhance P removal. Sediment deposition, infiltration, and plant adsorption are the primary mechanisms for phosphorus trapping in VFS.     

Book reviews

Sustainable Industrialisation. David Wallace, 1996, London, Royal Institute of International Affairs, (Earthscan), 120 pp. ISBN 1 85383 352 5, £11.95 (pbk)

Managing Green Technologies for Global Competitiveness. Christian Ndubisi Madu, 1996, London, Quorum Books, distributed by Eurospan, ISBN 0 89930 827 9, £47.95 (hbk)

Greening People, Human Resources and Environmental Management. Walter Wehrmeyer (Ed.) 1996, Sheffield, Greenleaf Publishing, 416 pp. ISBN 1 874719 15 2, £29.50 (hbk)

The Environment for Children: understanding and acting on the environmental hazards that threaten children and their parents. David Satterthwaite, Roger Hart, Caren Levy, Diana Mitlin, David Ross, Jac Smit & Carolyn Stephens, 1996, London, Earthscan Publications, 284 pp. ISBN 1 85383 326 6, £13.95

Local Sustainability: managing and planning ecologically sound places. Paul Selman, 1996, London, Paul Chapman, x + 175pp, index. ISBN 1 85396 300 3, £14.95     

CLEAN WATER ACT REAUTHORIZATION: HOW FAR HAVE WE COME?1

ABSTRACT: This paper first presents a brief review of an earlier effort to estimate the benefits associated with achieving the Clean Water Act objectives. It then discusses what would be involved in doing a retrospective benefit-cost analysis of the Clean Water Act and some information on changes in several measures of water quality over the past 20 years. The paper concludes with a summary of a recent effort to estimate the realized benefits associated with the Clean Water Act and some implications for policy. (KEY TERMS: benefits; benefit-cost analysis; costs; recreation; water pollution; water quality.)