Littoral microcrustacean (Cladocera and Copepoda) indicators of acidification in Canadian Shield lakes

We identify littoral microcrustacean indicators of acidification in 2 surveys of Canadian Shield lakes conducted 10 years apart. We found a total of 90 cladoceran and copepod species with richness increasing severalfold from acidic to nonacidic lakes. The fauna of the nonacidic lakes differed between the surveys. The 1987 survey employed activity traps, and caught more littoral taxa than the more recent, net-haul-based survey. Similar faunas were identified in the acidified lakes in both surveys, and several good indicator species were identified. For example, Acanthocycops vernalis was restricted to lakes with pH < 6. Sinobosmina sp. was very common but only in lakes with pH > 4.8. Tropocyclops extensus, Mesocyclops edax, and Sida crystallina were commonly found but only at pH > 5, and Chydorus faviformis only at pH > 5.9. These indicators showed promise in gauging the early stages of recovery from acidification in 3 lakes that were included in both surveys.     

Phylogeographic patterns of the mysid Mesopodopsis slabberi (Crustacea, Mysida) in Western Europe: evidence for high molecular diversity and cryptic speciation

The phylogeographic patterns among populations of Mesopodopsis slabberi (Crustacea, Mysida), an ecological important mysid species of marine and estuarine habitats, were analysed by means of DNA sequencing of a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) and the 16S ribosomal RNA genes. Samples of M. slabberi collected from five Atlantic and two Western Mediterranean populations were investigated. Very high levels of within-population molecular diversity were observed in all samples (mean h=0.807 and π=0.0083), with exception of the Mediterranean Ebro population which contained only one haplotype. Differentiation among populations was high, and a clear phylogeographic break was observed between the Atlantic and Mediterranean populations. Moreover, a strong differentiation was detected between both populations in the Western Mediterranean Sea (Alicante and Ebro delta), while two divergent lineages occurred in sympatry within the Atlantic Mondego estuary. The high congruence between both the COI and 16S rRNA sequence data, the reciprocal monophyly of the different mitochondrial clades and the levels of nucleotide divergence between them suggest the presence of a complex of cryptic species within M. slabberi. Estimations of divergence time between the different mitochondrial lineages indicate that a split occurred during the late Miocene/early Pliocene. Such a divergence could be concordant with vicariant events during sea-level drops within the Mediterranean region at that time. However, within the Mediterranean Sea, the potential of divergence through ecological diversification cannot be ruled out.     

Ecological Correlates of Species Success in Modified Habitats May Be Disturbance- and Site-Specific: The Primates of Tiwai Island

I compared primate abundances in an old forest and in adjacent regenerating farm clearings abandoned by slash-and-burn agriculturalists in Sierra Leone, West Africa. Univariate correlation procedures were used to identify socioecological characteristics of primate species that best explained success (abundance) of primates in regenerating farm clearings adjacent to old forest. A highly frugivorous diet was the single most significant primate characteristic correlated with use of abandoned farms (r_s = 0.886, p = 0.019). In contrast, other studies of primates in disturbed habitats determined that a frugivorous diet was strongly negatively correlated with primate use of selectively logged forest and other disturbed habitats. These contrasting results expose the hazard of generalizing about ecological correlates of primate success in disturbed habitats, which may be site or disturbance specific. Although this warning is derived from studies of primates, it may apply to other taxa as well.     

Training Conservation Biologists in Human Interaction Skills

Questionnaires were sent to 298 graduate programs in conservation biology and other areas of the biological and agricultural sciences and to 702 public and private organizations that employ, or might employ, conservation biologists. The focus of the questionnaires was on the need for training conservation biologists in human interaction skills (e.g., interpersonal communication, leadership, group decision making). Respondents were asked to indicate the current availability of such training at their institutions or organizations. Questionnaires were returned by 28.5% of the graduate programs and 21.1% of the conservation organizations. A majority of both groups of respondents indicated a high need for training in the following seven areas: written and oral communication; explaining science and values of biodiversity to the lay public; group decision making; interpersonal skills; group planning; leadership; and advocacy. Despite the high level of perceived training need, relatively few academic institutions and even fewer conservation organizations offer or require courses in human interaction skills (with the exceptions of written and oral communication and foreign languages). Sixty-four percent of the graduate faculty respondents and 78% of the employer organization respondents indicated that human interaction skills are equally important or more important to the work of conservation biologists than science knowledge and skill. We suggest that follow-up research should be conducted to delineate further the need for human interaction skills training and to assess the relationship between specific human interactions skills and conservation outcomes. We also recommend that a curriculum on human interaction should be designed and developed for conservation biologists, perhaps through a cooperative effort of interested faculty and employers facilitated by the Society for Conservation Biology and conservation organizations.     

Investigating freshwater periphyton community response to uranium with phospholipid fatty acid and denaturing gradient gel electrophoresis analyses

Periphyton communities can be used as monitors of ecosystem health and as indicators of contamination in lotic systems. Measures of biomass, community structure, and genetic diversity were used to investigate impacts of uranium (U) exposure on periphyton. Laboratory exposures of periphyton in river water amended with 238U were performed for 5 days, followed by 2 days of U depuration in unamended river water. Productivity as measured by biomass was not affected by concentrations up to 100 microg238U L(-1). Phospholipid fatty acid (PLFA) profiles and denaturing gradient gel electrophoresis (DGGE) banding patterns revealed no changes in community or genetic structure related to U exposure. We suggest that the periphyton community as a whole was not significantly impacted by exposures of 238U up to a concentration of 100 microgL(-1). These findings have significance for the assessment and prediction of U impacts on aquatic ecosystems.     

Courtship and reproduction in<Emphasis Type="Italic"> Carybdea sivickisi</Emphasis> (Cnidaria: Cubozoa)

Courtship and fertilization events in cubozoans have received little attention from biologists, and much of what we know about these processes is based on conjecture or scant anecdotal evidence. I set out to describe these processes in the cubozoan Carybdea sivickisi by observing mature medusae in vitro. Mature adults engage in courtship during which spermatophores are transferred from the male to the female, who then inserts the gametes into her manubrium. Females accepted multiple spermatophores from multiple males, and only produced one embryo strand. This study also provides evidence that the presence of conspicuous velar spots on the females bell margin is a signal of sexual maturity, and that sexual maturity was not reached in either sex until individuals had a bell diameter of at least 5 mm.Communicated by R.J. Thompson, St. Johns     

Respondent Experience and Contingent Valuation of Environmental Goods

Respondent experience (i.e., a respondent's information set) has long been suspected to influence contingent valuation estimates of environmental values. We assess the influence of experience by explicitly modeling the relationship between respondent experience and both fitted individual resource values and the conditional variance of these estimated values. Using three different joint specifications for experience and WTP—normal/censored-normal, Poisson/censored-normal, and zero-inflated Poisson/censored-normal—we find discrete jumps in resource values as experience increases from zero and that more-experienced respondents have smaller conditional variances. Simulation of arbitrary levels of experience allows standardization of the amount of information when developing welfare estimates.