Potential Economic Impacts of Environmental Flows Following a Possible Listing of Endangered Texas Freshwater Mussels

Texas water resources, already taxed by drought and population growth, could be further stressed by possible listings of endangered aquatic species. This study estimated potential economic impacts of environmental flows (EFs) for five freshwater unionid mussels in three Central Texas basins (Brazos, Colorado, and Guadalupe‐San Antonio Rivers) that encompass 36% of Texas (~246,000 km²). A water availability model projected reductions in water supply to power, commercial and industrial, municipal, and agriculture sectors in response to possible EFs for mussels. Single‐year economic impacts were calculated using publicly available data with and without water transfers. Benefits of EFs should also be assessed, should critical habitat be proposed. Potential economic losses were highest during droughts, but were nominal (<$1 M) in wetter years — even with high EFs. Reduced supplies to San Antonio area power plants caused worst‐case impacts of a single‐year shutdown up to $107 million (M) during drought with high EFs. For other sectors in the study area, water transfers reduced worst‐case losses from $80 to $11 M per year. Implementing innovative water management strategies such as water markets, conjunctive use of surface water and groundwater, aquifer storage and recovery could mitigate economic impacts if mussels — or other widely distributed aquatic species — were listed. However, approaches for defining EFs and strategies for mitigating economic impacts of EFs are needed.     

Land Management Restrictions and Options for Change in Perpetual Conservation Easements

Conservation organizations rely on conservation easements for diverse purposes, including protection of species and natural communities, working forests, and open space. This research investigated how perpetual conservation easements incorporated property rights, responsibilities, and options for change over time in land management. We compared 34 conservation easements held by one federal, three state, and four nonprofit organizations in Wisconsin. They incorporated six mechanisms for ongoing land management decision-making: management plans (74 %), modifications to permitted landowner uses with discretionary consent (65 %), amendment clauses (53 %), easement holder rights to conduct land management (50 %), reference to laws or policies as compliance terms (47 %), and conditional use permits (12 %). Easements with purposes to protect species and natural communities had more ecological monitoring rights, organizational control over land management, and mechanisms for change than easements with general open space purposes. Forestry purposes were associated with mechanisms for change but not necessarily with ecological monitoring rights or organizational control over land management. The Natural Resources Conservation Service-Wetland Reserve Program had a particularly consistent approach with high control over land use and some discretion to modify uses through permits. Conservation staff perceived a need to respond to changing social and ecological conditions but were divided on whether climate change was likely to negatively impact their conservation easements. Many conservation easements involved significant constraints on easement holders’ options for altering land management to achieve conservation purposes over time. This study suggests the need for greater attention to easement drafting, monitoring, and ongoing decision processes to ensure the public benefits of land conservation in changing landscapes.     

Case studies of scenario analysis for adaptive management of natural resource and infrastructure systems

Management of natural resources and infrastructure systems for sustainability is complicated by uncertainties in the human and natural environment. Moreover, decisions are further complicated by contradictory views, values, and concerns that are rarely made explicit. Scenario analysis can play a major role in addressing the challenges of sustainability management, especially the core question of how to scan the future in a structured, integrated, participatory, and policy-relevant manner. In a context of systems engineering, scenario analysis can provide an integrated and timely understanding of emergent conditions and help to avoid regret and belated action. The purpose of this paper is to present several case studies in natural resources and infrastructure systems management where scenario analysis has been used to aide decision making under uncertainty. The case studies include several resource and infrastructure systems: (1) water resources (2) land-use corridors (3) energy infrastructure, and (4) coastal climate change adaptation. The case studies emphasize a participatory approach, where scenario analysis becomes a means of incorporating diverse stakeholder concerns and experience. This approach to scenario analysis provides insight into both high-performing and robust initiatives/policies, and, perhaps more importantly, influential scenarios. Identifying the scenarios that are most influential to policy making helps to direct further investigative analysis, modeling, and data-collection efforts to support the learning process that is emphasized in adaptive management.     

IMPLICATIONS OF A DRAWDOWN OF THE SNAKE-COLUMBIA RWER ON BARGE TRANSPORTATION1

ABSTRACT: The listing of the Snake-Columbia River salmon under the Endangered species Cut will lead to a set of river management changes aimed at species recovery. One measure almost certain to be implemented is a periodic river drawdown. A drawdown will speed fish migration downriver but will also temporarily close the river to barge transportation. Grain shippers in the region rely on the barge carriage to move a significant share of annual production to export elevators on the Lower Columbia. A number of other bulk commodities utilize barges as well. This study outlines the aggregate and distributional economic implications of a suspension of barge transportation resulting from a river drawdown.     

Conflict and Impacts of Divers and Anglers in a Marine Park

The New South Wales State Government (Australia) gazetted the Jervis Bay Marine Park (JBMP) in 1998. During the preparation of the draft zoning plan in 2000, societal data on two conflicting park user groups—recreational scuba divers and fishers (anglers)—was collected. While conflict resolution was a plan priority, other factors, such as cumulative environmental impacts of users and protection for the critically endangered grey nurse shark (Carcharias taurus), further complicated planning. Both scuba diving and angling are primary summer activities and are disproportionately concentrated around the headlands of the bay. Furthermore, shore based game-fishing was concentrated on the northern headland, where the conflict was centered. However, when the exact locations of divers and anglers were determined, there was a partial partitioning of the available space, with only a small contested overlap. To resolve conflict and maximize positive environmental outcomes, a sanctuary zone and no-anchoring zone option in the draft zoning plan was sought to formalize this partition. The human dimension data proved valuable in guiding environmental management in this politically volatile situation. A baseline study conducted 11 years previously was also used to gain a limited perspective on change in user numbers. Comparison between study periods indicated dive numbers had remained similar, while the number of dive charter trips was significantly less. The numbers of anglers, for the four months compared, had doubled and tripled. The actual data used to inform management is presented and the limitations of this best available data approach are discussed.     

ESCHERICHIA COLI SURVIVAL IN MANTLED KARST SPRINGS AND STREAMS,NORTHWEST ARKANSAS OZARKS,USA1

Recent studies indicate fecal coliform bacterial concentrations, including Escherichia coli (E. coli), characteristically vary by several orders of magnitude, depending on the hydrology of storm recharge and discharge. E. coli concentrations in spring water increase rapidly during the rising limb of a storm hydrograph, peak prior to or coincident with the peak of the storm pulse, and decline rapidly, well before the recession of the storm hydrograph. This suggests E. coli are associated with resuspension of sediment during the onset of turbulent flow, and indicates viable bacteria reside within the spring and stream sediments. E. coli inoculated chambers were placed in spring and stream environments within the mantled karst of northwest Arkansas to assess long term (> 75 days) E. coli viability. During the 75‐day study, a 4‐log die‐off of E. coli was observed for chambers placed in the Illinois River, and a 5‐log die‐off for chambers placed in Copperhead Spring. Extrapolation of the regression line for each environment indicates E. coli concentration would reach 1 most probable number (MPN)/100 g sediment at Copperhead Spring in about 105 days, and about 135 days in the Illinois River, based on a starting inoculation of 2.5 × 107 MPN E. coli/100 g of sediment. These in situ observations indicate it is possible for E. coli to survive in these environments for at least four months with no fresh external inputs.     

Natal male baboon rank rises and successful challenges to resident alpha males

Summary After an interval (X = 6 months), high ranking male chacma baboons (Papio cynocephalus ursinus) lose their status to immigrants. Attainment of alpha rank by immigrants is a qualitatively different process from thestepwise increase in status noted in linear dominance hierarchies. The departing rank of natal emigrants was 5.4, while the first measured rank, shortly after transfer into a new troop, was 1.5. Abrupt rises to alpha rank involve direct challenges to the current alpha male. Fourteen of 19 prime immigrants attained alpha rank at first transfer. Rank rises may result if individuals forego contests, retaining lower hierarchical positions in their natal troop to avoid the costs of conflict prior to natal emigration. In this population some males do breed in their natal troops without differing from immigrants in their reprodocutive success. Five males that rose to high rank within their natal troops also made rapid rank rises to the top of the hierarchy. Withholding of aggressive efforts in natal troops to avoid inbreeding thus is not an adequate explanation of the rank rises we observe in this population. The high probability of successful challenges can be explained by assuming an asymmetry in costs of losing (resource value) to tenured alpha males or a greater fighting ability of challengers. Offprint requests to: W.J. Hamilton III     

A CATALYST FOR REGIONALIZATION OF RURAL WATER SYSTEMS1

ABSTRACT: The National Regulatory Research Institute has recommended the merger of small rural water districts in the United States. Success at bringing about merger of these districts, which contain fewer than 3,500 customers, has been highly limited. The subject of this paper is a demonstration project that may act as a catalyst to achieve the desired goal of regionalization. A computerized hydraulic data management program (CHDMP) was developed for a case study in Nelson County, Kentucky. University professors, graduate students, and two water utilities’ staffs cooperated in network analysis employing computer hardware and software. The utilities’ staffs were taught the science and technology of hydraulic model preparation, simulation, and analysis for the case study distribution systems. As an integrated system, the model contained 294 pipes, 234 nodes, six pumps, and 11 tanks. Each utility's problem areas were identified and some of the individual and mutual benefits of hydraulic planning were illustrated. A dialogue resulted between the managers. Each manager described his goals and agreed that, although political merger was not feasible at the present time, future economic factors could be a definite influence in reversing that decision.