Population biology ofMacrocystis integrifolia from British Columbia,Canada

Aspects of the population dynamics ofMacrocystis integrifolia Bory were determined from harvested wild populations over a 26-month period and cultivated plants over a 40-month period. Mean wild plant size varied from 0.1 wet kg and two fronds in the winter to 3.1 wet kg and mine fronds in the summer. Plant recruitment probably occurred year-round with recruits making up 20 to 86% of the total population. Plant half-lives, estimated from population data, ranged from 1 to 3 months, with few plants exceedings 2 to 3 years in age. Standing crop ranged from 1.6 plants m^-2 and 0.1 wet kg m^-2 in winter to 8.3 plants m^-2 and 8 wet kg m^-2 in summer.     

Anheuser-busch's a pledge and a promise: Total employee involvement

Anheuser-Busch is a large, diversified corporation, both in its products and in its environmental efforts. It is well-known that Anheuser-Busch is the world'S largest brewer, with twelve operating breweries and a thirteenth under construction. It also operates the largest aluminum can recycling network in the world, Anheuser-Busch Recycling (A-BR). A-BR recycled more than 600 million pounds of aluminum in 1991, or more than 17 billion cans. This article describes how Anheuser-Busch has put TQEM ideas into practice involving all of its employees.     

Making Sense of the Policy Process for Carnivore Conservation

Grizzly bears ( Ursus arctos horribilis ), mountain lions ( Puma concolor ), wolverines ( Gulo gulo ), wolves ( Canis lupus ), and lynx ( Felis lynx ) are all top-level carnivores in the Rocky Mountains of the northern U.S. and southern Canada. Because of their body size and high trophic position, these species require abundant prey species and large habitat areas—requirements that make their conservation a controversial public policy problem. Because the challenge of conserving these species extends beyond biological issues, it is necessary to involve other relevant disciplines and perspectives in understanding and solving the problem. Our examination of the context, content, and process of large carnivore conservation policies suggests more effective and active roles for scientists in designing solutions to the problem of landscape-level carnivore conservation. Scientists must develop an understanding of the range of participants in the policy process and the ways in which these participants receive and utilize information. This knowledge of the policy process could help scientists to better understand their roles in framing and clarifying policy questions, projecting the consequences of various alternatives, and presenting policy information in appropriate fora.     

Landscape Patterns of Florida Scrub Jay Habitat Use and Demographic Success

Remote sensing and geographical information systems are used to analyze landscapes important to species of conservation concern. The accuracy of the methods depends on how closely habitat mapping classes are linked to population demography. Habitat use by Florida Scrub Jays ( Aphelocoma c. coemlescens ) was quantified using circular plots. Habitat variation was mapped using high-resolution aerial photography on a site where all Florida Scrub Jays were color-banded. Nest site selection, nest success, yearling production, and breeder survival were measured within Florida Scrub Jay territories. Habitat use was lowest in areas without scrub oaks or areas within 136 m from forests. Open oak, dominated by scrub oaks and open sandy areas, had the highest use and nest success among habitats. Open oak occurred as narrow patches ( <20 m wide) in landscapes dominated by matrix habitat (palmetto-lyonia and swale marshes). Most wide patches (>50 m) of open oak were potential population sources, where reproduction exceeded mortality. Areas with patches of open oak of less than 1 ha were usually population sinks. Open oak occurred as less flammable patches in a landscape subject to frequent fires. Population sources varied temporally and spatially with fires and site potential to support scrub oaks (soils). Analyses of landscape patterns and dynamics indicated that habitat mapping should not only include patches of currently optimal habitat but should also include landscapes associated with open oak. The influences of landscape patterns on habitat use, reproductive success, survival, and territory size can be quantified at different scales starting with attributes associated with habitat patches, nest sites, and territories. Potential mapping errors occur, however, when habitats are used to quantify the areal extent of sources and sinks and similar population attributes important for species persistence.     

Aerobic ethanol production by leaves: Evidence for air pollution stress in trees of the Ohio River Valley, USA

We measured the frequency with which leaves of trees in the Ohio River Valley produced ethanol aerobically, to determine if aerobic ethanol production might provide a viable field assay for air pollution stress. Leaves were collected from trees during the summers of 1985 and 1986 and ethanol production was determined using headspace GC. Frequency of ethanol production was compared with environmental factors, including air pollution concentrations. We found frequent foliar ethanol production and elevated alcohol dehydrogenase activity in the leaves of several species of trees in the Ohio River Valley, USA. The ethanol concentrations measured were often equivalent to those produced by anaerobic leaves. Ethanol production was associated with hot, hazy weather and elevated NO(2) concentrations. Ethanol production was more frequent in urban and industrialized areas. Ethanol production was not associated with natural stresses such as flooding and herbivory. We propose that aerobic ethanol production is the result of cell acidification due to the accumulation of acidic gases in the cytoplasm. The use of ethanol production as a diagnostic tool for detecting stress imposed by acidic gases is discussed.     

Morphological correlates of intraspecific grafting reactions in the marine demosponge Callyspongia diffusa

There are profound differences in the ways that the sponge Callyspongia diffusa reacts to self versus non-self tissue contact. Syngeneic or isogeneic contacts result in rapid tissue fusion and persistent maintenance of normal sponge structure. However, allogeneic contacts result in immune-type rejection reactions leading to tissue death at the interface. Using grafted sponge tissues, both types of response were subject to fine-structural analysis by scanning electron microscopy. Isografts showed no overt cellular reactions other than compatible fusion, whereas sponge tissues at allograft interfaces showed incompatibility reactions. The major steps in the histopathologic sequence of events in allograft reactions may be summarized as follows: (1) immediate allorecognition occurs accompanied by microscopic cellular rearrangements; (2) macroscopic tissue bridges form across the graft interface; (3) massive cellular infiltration towards graft sites, with cells often passing into a graft partner through the tissue bridges; (4) cellular hyperplasia and then cell death occurs at the interface; and (5) sloughing of dead tissue leaves areas of vacant skeleton between the two grafted individuals. Allograft rejection reactions in sponges have many of the hallmarks of histoincompatibility reactions in higher animals. Although there could be different alloimmune mechanisms operating in different animals, the salient events of allorecognition and antagonistic rejection appear strikingly similar among diverse multicellular animals.