Inter- and intra-sexual patterns of fluctuating asymmetry in the red-billed streamertail: should symmetry always increase with ornament size?

Recent work on fluctuating asymmetry has suggested that ornaments should have higher levels of fluctuating asymmetry than (1) non-ornaments and (2) homologous structures in the non-ornamented sex. In addition, as both ornament size and symmetry should increase with individual quality there should be a tendency for ornament symmetry to increase with ornament size. In non-ornaments, a U-shaped relationship between symmetry and size is expected, with the individuals at the extremes being more asymmetrical than individuals around the optimum. We tested these predictions in the red-billed streamertail (Trochilus polytmus), a sexually dimorphic endemic Jamaican hummingbird. The lengths of four bilaterally symmetrical traits (first and second outermost tail feathers, tarsi and wings) in 43 adult males and 42 females were measured. The second outermost tail feathers of adult males (which are elongated into streamers) were absolutely but not relatively more asymmetrical than non-ornaments (including the homologous feathers in females). When character size was controlled for, wings were shown to be relatively more symmetrical than other traits. Symmetry did not increase with increasing trait size in any of the morphological traits measured. There was a U-shaped relationship between asymmetry and trait size for four traits (adult male streamers, adult male wings and female outer tail feathers). These results do not support any of the predictions made by fluctuating asymmetry hypotheses and suggest that stabilising selection may act on ornaments as well as non-ornaments. These predictions have been supported in swallows and peafowl but not in sunbirds; this may be due to differences in female perception of tail ornaments. Perhaps male tails do not convey information about quality in some species, or there may be inter-specific differences in the relative costs of tail ornaments and the benefit of marginal increases in tail length and symmetry.     

STATE WATER PLANNING: A FORUM FOR PROACTWELY RESOLVING WATER POLICY DISPUTES1

ABSTRACT: In the arid West, the development and implementation of water policy often results in disputes among water users, resource managers, and policy makers. Although significant attempts have been made to improve public involvement and dispute resolution in water resources planning, the traditional planning process has not historically played this role for a variety of reasons. Water resources planning can become a forum for proactively resolving water policy disputes by employing the principles of environmental dispute resolution. The purpose of this article is to explore the role of collaborative, consensus-building planning processes in resolving water policy disputes. The Montana State Water Plan is evaluated as an example of such a process, and a model state water planning process is outlined.     

Characterization of saccharides and other organic compounds in fine particles and the use of saccharides to track primary biologically derived carbon sources

A total of 134 aerosol samples (d_p < 2.5 μm) were collected at one rural site and one urban site in Texas from November 2005 to July 2006 to investigate the different sources that contribute to the ambient levels of different compounds. In particular, saccharide compounds were studied as potential tracers to track aerosols of biologically derived origin. The ambient concentration, seasonal variation, and urban/rural comparison of major saccharides and other organic compounds including normal alkanes, hopanes, and carboxylic acids were determined and analyzed relative to characterizing sources of PM2.5. Saccharides, together with other known molecular markers, were analyzed by a positive matrix factorization model and eight source factors were isolated that provide meaningful interpretation of aerosol sources. Three isolated factors were characterized by the dominance of different saccharide compounds and were attributed to wood smoke, sucrose rich bio-aerosols, and fungal spore derived bio-aerosols. It was estimated that wood smoke and primary biologically derived carbon sources contributed 22% and 14% to the measured ambient PM2.5 mass at San Augustine and 16% and 5% to the measured ambient PM2.5 mass at Dallas. The relative PM contribution from other resolved sources were also calculated.     

Three-spined stickleback: an emerging model in environmental endocrine disruption.

The three-spined stickleback, a small teleost species with habitats that range from full marine to fresh water bodies across the whole Northern hemisphere, has a number of advantages for endocrine disruption research. It is the only teleost species with an unambiguous biomarker for androgens, the presence of the glue protein spiggin in the male kidney, which can be measured by enzyme-linked immunosorbent assay (ELISA). The androgen assay has been adopted to detect antiandrogens in two different ways and an homologous ELISA for stickleback vitellogenin is also available. DNA markers for molecular sex determination are available; thus, sex ratios can also be used for in situ biomonitoring. In addition, the critical period of sexual differentiation has been determined and the occurrence of intersex fish has been reported several times. The species full genome sequence is almost complete. All aspects of stickleback biology (ecology, evolution, behavior, physiology, endocrinology) are well documented. In European waters, the stickleback is the only fish that can bring laboratory and field studies together and allow the true impact of endocrine disruptors on fish populations to be evaluated.     

Planning for persistence in marine reserves: a question of catastrophic importance.

Large-scale catastrophic events, although rare, lie generally beyond the control of local management and can prevent marine reserves from achieving biodiversity outcomes. We formulate a new conservation planning problem that aims to minimize the probability of missing conservation targets as a result of catastrophic events. To illustrate this approach we formulate and solve the problem of minimizing the impact of large-scale coral bleaching events on a reserve system for the Great Barrier Reef, Australia. We show that by considering the threat of catastrophic events as part of the reserve design problem it is possible to substantially improve the likely persistence of conservation features within reserve networks for a negligible increase in cost. In the case of the Great Barrier Reef, a 2% increase in overall reserve cost was enough to improve the long-run performance of our reserve network by >60%. Our results also demonstrate that simply aiming to protect the reefs at lowest risk of catastrophic bleaching does not necessarily lead to the best conservation outcomes, and enormous gains in overall persistence can be made by removing the requirement to represent all bioregions in the reserve network. We provide an explicit and well-defined method that allows the probability of catastrophic disturbances to be included in the site selection problem without creating additional conservation targets or imposing arbitrary presence/absence thresholds on existing data. This research has implications for reserve design in a changing climate.     

Allowable levels of take for the trade in Nearctic songbirds

The take of Nearctic songbirds for the caged-bird trade is an important cultural and economic activity in Mexico, but its sustainability has been questioned. We relied on the theta-logistic population model to explore options for setting allowable levels of take for 11 species of passerines that were subject to legal take in Mexico in 2010. Because estimates of population size necessary for making-periodic adjustments to levels of take are not routinely available, we examined the conditions under which a constant level of take might contribute to population depletion (i.e., a population below its level of maximum net productivity). The chance of depleting a population is highest when levels of take are based on population sizes that happen to be much lower or higher than the level of maximum net productivity, when environmental variation is relatively high and serially correlated, and when the interval between estimation of population size is relatively long (> or = 5 years). To estimate demographic rates of songbirds involved in the Mexican trade we relied on published information and allometric relationships to develop probability distributions for key rates, and then sampled from those distributions to characterize the uncertainty in potential levels of take. Estimates of the intrinsic rate of growth (r) were highly variable, but median estimates were consistent with those expected for relatively short-lived, highly fecund species. Allowing for the possibility of nonlinear density dependence generally resulted in allowable levels of take that were lower than would have been the case under an assumption of linearity. Levels of take authorized by the Mexican government in 2010 for the 11 species we examined were small in comparison to relatively conservative allowable levels of take (i.e., those intended to achieve 50% of maximum sustainable yield). However, the actual levels of take in Mexico are unknown and almost certainly exceed the authorized take. Also, the take of Nearctic songbirds in other Latin American and Caribbean countries ultimately must be considered in assessing population-level impacts.     

Whole-community mutualism: associated invertebrates facilitate a dominant habitat-forming seaweed

Many habitat-forming, or foundation, species harbor diverse assemblages of associated taxa that benefit from the refuges from predators or harsh physical conditions that foundation species provide. Growing numbers of studies show how specific taxa associated with foundation species can benefit their hosts, but the aggregate effects of the entire community of associated species remain poorly understood. Here, we evaluate the role that a diverse assemblage of invertebrates plays in mediating the dominance of a foundation species, the green filamentous seaweed Cladophora columbiana Collins, in rocky intertidal habitats. Cladophora is a fast-growing seaweed with a high nitrogen demand, and we suggest that it persists in nutrient-limited high-intertidal pools because of local-scale nitrogen excretion by the invertebrate taxa living within its filaments. Removal of associated invertebrates resulted in a fourfold increase in the rate of water-column nitrogen depletion by Cladophora, and ammonium concentrations inside Cladophora turfs with invertebrates present were seven times higher than in the adjacent tide-pool water. The ammonium excreted by invertebrate meiofauna far surpassed the nitrogen used by Cladophora, suggesting that all of Cladophora's nitrogen requirements could be met by the invertebrates associated with it. This study links host performance to the total aggregate biomass of mutualists rather than the particular traits of any one species, suggesting the potential for important feedbacks between individual hosts and the communities of associated species that they support.