Biological Control of Water Hyacinth Under Conditions of Maintenance Management: Can Herbicides and Insects Be Integrated?

Neochetina eichhorniae and N. bruchi. We therefore sampled water hyacinth and weevil populations at 54 sites distributed statewide. Half were under maintenance control, half were not treated with herbicides. General site conditions were assessed, demographic data were collected on weevil and plant populations, the reproductive condition of the weevils was determined, and plant nutrient and proximate composition of water hyacinth leaves were analyzed. Water hyacinth infestations under maintenance control were minimal when compared to unmanaged sites. Likewise, on a population basis, all weevil cohorts were much lower due to the paucity of plants. Plants at unmanaged sites, where weevil intensities were much higher, suffered high levels of stress and showed low growth potential. Lower percentages of the female weevils were reproductive at unmanaged sites when compared to managed sites, so densities of reproductives and immatures were similar at both site types. Reproductive status of the weevils improved with increased plant quality. Plant quality, in turn, declined as stresses arising from weevil feeding increased. Plant quality was positively correlated with plant growth potential and flower production. Thus, maintenance control improved plant nutritive quality thereby inducing reproductive vigor of the weevils, but ensuring plant regrowth and the need for future control. This suggests that biological and herbicidal controls should be integrated, using herbicides to maintain water hyacinth infestations below management thresholds but in a manner that conserves biological control agent populations. This approach would lead to improved plant nutritional quality that would, in turn, stimulate reproduction in biological control agent populations.     

STAKEHOLDER INVOLVEMENT AND SOCIAL CAPITAL: KEYS TO WATERSHED MANAGEMENT SUCCESS IN ALABAMA1

ABSTRACT: Forces driving the initiation of watershed management activities in Alabama have ranged from top-down, agency-led initiatives to bottom-up, citizen-led initiatives. A number of watershed projects in Alabama were examined including three NPS projects funded by U.S. EPA grants and a more comprehensive locally-initiated watershed management authority. Watershed projects were categorized into four different models. Factors which produced significant differences in the development and utilization of social capital and local capacities for watershed management were investigated. The success of watershed management initiatives was examined qualitatively and appears to correlate with a number of social factors. These factors include the extent of stakeholder involvement, the availability of social capital in the watershed, and the presence of a real or perceived water resource concern or problem. Both short term project success and the longer term prognosis for continued watershed management activities seems to depend most upon the amount of social capital in the watershed. Two major changes in resource management programs and organizations could lead to increased focus on and support for local watershed management initiatives. These are reorganization of resource management agencies around watershed units, and assignment of at least one staff person in each watershed unit to watershed management.     

Indicators for change: Taking a lead

The authors argue that sustainable development is a political concept arising from interactions between socio-economic and physical systems. As such, political values are implicit in many qualitative aspects of sustainability and its communication through indicators. In Great Britain, local government has played the lead role in Local Agenda 21, involving interest groups and community organisations in varying degrees, through public participation. However, the need for local solutions to sustainability problems also exists in Northern Ireland, where governmental bodies are unwilling or unable to accept responsibility for Local Agenda 21. In the Northern Ireland context, the evolving role of Non-Governmental Organisations (NGOs) and the community sector in the indicators issue has been markedly different to that in the rest of the UK. There are potential problems concerning political values and mandates when the NGO/community sector assumes the lead in such tasks. The authors argue that, while criticisms of explicit and/or implied political values can be well grounded, addressing these must go beyond questions of objectivity in collection and presentation of indicators and projects must be understood by developing feedback and review mechanisms. The authors review the Northern Ireland sustainability indicators project and evaluate the feedback procedures in place. Lessons learnt from this exercise are explored with reference to (i) the current organisation of Local Agenda 21 within local government in Northern Ireland and (ii) national and international parallels.     

Relatedness and avoidance of inbreeding in the lizard, Tiliqua rugosa

Two potential mechanisms for reducing the level of inbreeding, sex-biased dispersal and kin avoidance, were examined in the Australian sleepy lizard, Tiliqua rugosa. The home range centres, and the genotypes at four polymorphic microsatellite DNA loci were determined for adult lizards in a 70-ha study area near Mount Mary, South Australia. From estimates of genetic relatedness, females were as closely related to other females as they were to males, both within the whole study area, and within home ranges. Similarly, males were as closely related to other males as they were to females. This suggests that dispersal in the population is not sex-biased. Sleepy lizards form monogamous pairs during the spring. Partners were less closely related to each other than to other potential partners in the home range area. This suggests active choice of unrelated partners. The mechanism for recognising related from unrelated individuals is unknown, but the behaviour could reduce inbreeding. Received: 7 November 1998 / Accepted: 30 May 1999     

Chemical defense and evolutionary trends in biosynthetic capacity among dorid nudibranchs (Mollusca: Gastropoda: Opisthobranchia)

Summary. An evolutionary scenario incorporating recent advances in phylogenetic research begins with an opisthobranch-pulmonate common ancestor that was herbivorous and had some diet-derived chemical defense. The Nudibranchia and their closest relatives, the Notaspidea, form a lineage the ancestors of which had switched to feeding upon sponges and deriving protection from metabolites contained in them. Subsequently there have been repeated shifts in food and defensive metabolites, and trends are evident in the ability to detoxify, sequester and utilize metabolites from food, as well as to synthesize defensive compounds de novo. The Notaspidea display a minor adaptive radiation that foreshadows a more extensive one in the various lineages of nudibranchs. This review emphasizes changes that have occurred within the Holohepatica, or dorid nudibranchs (order Doridacea). Their sister-group, the Cladohepatica, consists of three other orders, Dendronotacea, Arminacea, and Aeolidiacea, in which there has been a shift from sponges to Cnidaria as food. The Dendronotacea often feed upon Octocorallia, which combine spicules, chemical defense, and stinging capsules and thereby suggest a transition from feeding on sponges. A previous diet of Octocorallia is suggested by the defensive use of prostaglandins in the dendronotacean Tethys fimbria, which eats crustaceans. A shift to bryozoans in some Arminacea is accompanied by use of different metabolites. Dorid nudibranchs evidently began as sponge-feeders, but some lineages have shifted to a variety of other food organisms, and others have specialized in the kind of sponges they feed on and how they do it. There have been shifts to bryozoans (Ectoprocta) and ascidians (Chordata: Urochordata) that track metabolites rather than the taxonomy of the food. There is a crude correlation between the genealogy and the defensive metabolites of the sponge-feeding dorids. De novo synthesis is well documented in this order and the metabolites are appropriately positioned so as to have an adaptive effect. The hypothesis that the capacity for de novo synthesis was acquired by gene transfer across lineages is rejected, partly on the basis of different chirality of metabolites in the nudibranchs and their food organisms. Instead it is proposed that there has been a preadaptive phase followed by evolution in a retrosynthetic mode, with selection favoring enzymes that enhance the yield of end products that are already present in the food. Received 5 February 1999; accepted 26 July 1999     

Identifying socioeconomic and biophysical factors driving forest loss in protected areas

Protected areas (PAs) are a commonly used strategy to confront forest conversion and biodiversity loss. Although determining drivers of forest loss is central to conservation success, understanding of them is limited by conventional modeling assumptions. We used random forest regression to evaluate potential drivers of deforestation in PAs in Mexico, while accounting for nonlinear relationships and higher order interactions underlying deforestation processes. Socioeconomic drivers (e.g., road density, human population density) and underlying biophysical conditions (e.g., precipitation, distance to water, elevation, slope) were stronger predictors of forest loss than PA characteristics, such as age, type, and management effectiveness. Within PA characteristics, variables reflecting collaborative and equitable management and PA size were the strongest predictors of forest loss, albeit with less explanatory power than socioeconomic and biophysical variables. In contrast to previously used methods, which typically have been based on the assumption of linear relationships, we found that the associations between most predictors and forest loss are nonlinear. Our results can inform decisions on the allocation of PA resources by strengthening management in PAs with the highest risk of deforestation and help preemptively protect key biodiversity areas that may be vulnerable to deforestation in the future.     

Pygmalion in work organizations: a meta‐analysis

The Pygmalion effect, a type of self‐fulfilling prophecy, has been demonstrated in educational settings with empirical studies, qualitative reviews and meta‐analyses. It has also been studied in organizational settings. This meta‐analysis provides a review of the Pygmalion literature, an analysis of findings to date, and a deeper look into the nature of the effect. The present analysis of 13 effect sizes revealed an overall d for the Pygmalion effect in work organizations of 0.81. Moderator analyses revealed stronger effects when the initial level of performance was low and when the experiment took place in a military rather than a business setting. Implications of these findings are discussed. Copyright © 2000 John Wiley & Sons, Ltd.