CHANGES IN PHYSICAL AND CHEMICAL VARIABLES IN A NEW RESERVOIR DUE TO PUMPED STORAGE OPERATIONS1

ABSTRACT: Information on biologically important physical and chemical variables is presented for Lake Oconee, a newly impounded pumped storage reservoir in Georgia. During its first summer, when no pumping occurred, temperature, oxygen, pH, inorganic nitrogen, and phosphorus were vertically stratified with severe hypolimnetic oxygen depletion. During the second summer, when pumped storage was in operation, more homogenous vertical profiles, generally higher oxygen, and lower dissolved nutrient concentrations were observed. These pumped storage effects were observed at all stations, rather than being confined to the immediate vicinity of the dam.     

Reproductive success of solitary and communal Philoponella oweni (Araneae: Uloboridae)

Summary Philoponella oweni (Uloboridae) is a facultatively communal orb-web spider found in arid regions in the southwestern United States. Within one habitat solitary adult females and communal groups of adult females coexist.This study compared the reproductive output (egg production) and reproductive success (production of live offspring) of solitary and communal females. There was no significant difference in the mean number of egg-cases produced by solitary and communal females, but communal females produced significantly more eggs per egg-case. However, communal females suffered significantly higher rates of egg-case parasitism from the pteromalid wasp Arachnopteromalus dasys. As a result, the mean number of liver offspring produced by solitary and communal females did not differ. Thus, both strategies led to roughly equal reproductive success. The advantages of aggregation of adults may be significant in the evolution of social behavior in spiders.     

Influence of ethnicity on recreation and natural environment use patterns: Managing recreation sites for ethnic and racial diversity

Management of natural environment sites is becoming increasingly complex because of the influx of urbanized society into wildland areas. This worldwide phenomenon impacts a wide range of countries. In southern California ethnicity is often a major factor influencing recreation site use and behavior at sites in the wildland-urban interface. This study investigated the role of ethnicity and race on the use patterns, perception of environment, and recreation behaviors at an outdoor recreation site visited by an ethnically diverse population. Two research questions were asked: (1) What ethnic groups engage in outdoor recreation at this site, and (2) what differences can be assigned to these various groups? Data were collected from 250 recreationists during 1991. Three major ethnic groups were identified, and statistically significant differences were found in the importance of site attributes, activity participation, and in preferred and actual communication channels. Management implications and strategies based on group differences are discussed.     

PLANNING FOR DROUGHT: THE ROLE OF STATE GOVERNMENT1

ABSTRACT: Although droughts are a frequent occurrence over much of the United States, response by state and federal government has been ineffective and poorly coordinated. Recently, several states have recognized the value of drought emergency planning and have developed plans to assist them in responding more effectively to prolonged periods of water shortage. These states have created an organizational structure to coordinate the assessment and response activities of state and federal agencies. Each state's drought response plan is unique since each state's water supply and management problems, and their consequent impacts, are unique. The drought response plans developed by Colorado, South Dakota and New York are reviewed here in detail. We recommend that other states affected by frequent and severe water shortages also develop drought emergency plans. These plans will enhance state government's ability to implement effective measures in a timely manner and, ultimately, may provide added incentive for the federal government to develop the national drought response plan called for by the General Accounting Office in 1979.     

VARIABILITY IN MEASURES OF MACROINVERTEBRATE COMMUNITY STRUCTURE BY STREAM REACH AND STREAM CLASS1

ABSTRACT: Macroinvertebrate community data collected from streams in Wyoming were assessed at various scales: within one stream reach, between stream reaches within one stream, between streams, and between stream classes. Fourteen indices including number of individuals/m², biomass/m², number of taxa, Shannon's diversity index, and functional feeding group ratios were used to compare macroinvertebrates by stream reach and stream class. Statistical analysis indicated that for five of the 14 indices, significant variability occurred between macroinvertebrate communities within one reach. For two of the remaining nine indices there was significant variability between communities from several reaches within the same stream. For seven of the nine indices, there was significant variability among macroinvertebrate communities from streams of the same class. Variability among the macroinvertebrate communities from the three stream classes was significantly different for seven of the nine indices. ANOVA results suggest that macroinvertebrate communities from different samples within one reach and between reaches within one stream were more comparable than those from different streams and different stream classes.     

Maternal provisioning of sequestered defensive steroids by the Asian snake <Emphasis Type="Italic">Rhabdophis tigrinus</Emphasis>

Summary.   Rhabdophis tigrinus obtains defensive steroids (bufadienolides) from its diet and sequesters those compounds in specialized structures on its neck known as nuchal glands. Hatchling snakes lacking these steroids must acquire them from toads consumed as prey. Here we show that females provision bufadienolides to their offspring in amounts correlated to the quantity in their own nuchal glands; thus, chemically protected mothers produce defended offspring. Bufadienolides can be provisioned to embryos via deposition in yolk and by transfer across the egg membranes within the oviducts. Maternally provisioned bufadienolides persist in the nuchal glands of juvenile snakes from the time of hatching in late summer until the following spring, when toads of ingestible size become abundant. Therefore, maternal provisioning may provide chemical protection from predators for young R. tigrinus in the absence of dietary sources of bufadienolides.     

Plant available phosphorus in soil as predictor for the leaching potential: Insights from long-term lysimeter studies

This study aimed to demonstrate the impact of phosphorus (P) mineral fertilization on topsoil P content and P leaching. We evaluated 83 datasets from 25 years from lysimeter experiments involving different cropping systems (winter crop, summer crop and autumn tillage, harvested grass) or unfertilized fallow, four types of soil texture, and three levels of applied mineral P fertilizer. A positive monotonic and significant correlation was indicated between P in the topsoil determined by the double lactate method (P _DL) and the yearly flow-weight total (TP) concentrations in leachates with Spearman rank correlations r _s (r _s > 0.183) and probability (p) < 0.05. The present German recommended rates of P mineral fertilization are proposed insufficient to protect fresh and marine waters from undesired P pollution and eutrophication. A long-term reduction of excess soil P is urgent along with other measures to mitigate high P inputs to surface and ground waters.     

Policy-adaptation for a smarter and more sustainable EU electricity distribution industry: a foresight analysis

The European Union (EU) transition to a smarter and more sustainable electricity sector is driven by climate change adaptation and technological developments. For the electricity distribution industry, this has contributed to a growing need to understand how these network monopolies should adapt their role, activities, and responsibilities for a redesigned electricity market, given the growth of distributed generation, and the increased control and monitoring capabilities. Considering this, a foresight study on business model innovation, technological adaptation, and market design policy alternatives is presented. A Policy Delphi method was applied, involving two iterative survey rounds and 207 European experts, which assessed 57 policy alternatives. The results highlight adaptation challenges for implementing new technologies and business practices. Experts support innovation and transition to new roles, and innovative services, while warranting that core electricity distribution activities are secured. This shift in roles is expected to be achieved through research and development (R&D) support policies, innovation friendly regulatory frameworks, and concerted actions at the EU and Member States level. The results provide policy-adaptation guidelines for electricity distribution industry stakeholders.