Boldness is influenced by sublethal interactions with predators and is associated with successful harem infiltration in Madagascar hissing cockroaches

One of the contemporary challenges of the behavioral syndromes literature is to identify how individual variation in behavior is determined, and whether this variation impacts ecological success. Although variation in experience is an obvious potential driver of intraspecific behavioral variation, predicting the impact of experience on suites of correlated behavioral traits is less intuitive. Specifically, if experience impacts traits that shape individuals' success in multiple contexts (e.g., foraging and anti-predator behavior), then experience could generate cross-contextual performance trade-offs associated with behavioral spillover. In the present study, we explore how sublethal experience with predators impacts various aspects of male behavioral tendencies in the Madagascar hissing cockroach, Gromphadorhina portentosa. First, we found that males' activity level and boldness were correlated together in the form of a behavioral syndrome. Second, we found that repeated sublethal interactions with predators shifted male boldness but not activity level, thus suggesting that the syndrome's constituent traits can respond to experience at least semi-independently. Third, we discovered that although predator exposure only influenced boldness, we found that boldness was highly correlated with males' ability to obtain rewarding positions in the harems of rival males. Taken together, our data suggest (but do not yet confirm) that although sublethal exposure to predators influences only a narrow subset of male's behavioral tendencies, these effects could still have nonintuitive consequences for males' success in functionally dissimilar ecological contexts (i.e., social and sexual encounters).     

Sampling designs on stream networks using the pseudo-Bayesian approach

Monitoring stream networks through time provides important ecological information. The sampling design problem is to choose locations where measurements are taken so as to maximise information gathered about physicochemical and biological variables on the stream network. This paper uses a pseudo-Bayesian approach, averaging a utility function over a prior distribution, in finding a design which maximizes the average utility. We use models for correlations of observations on the stream network that are based on stream network distances and described by moving average error models. Utility functions used reflect the needs of the experimenter, such as prediction of location values or estimation of parameters. We propose an algorithmic approach to design with the mean utility of a design estimated using Monte Carlo techniques and an exchange algorithm to search for optimal sampling designs. In particular we focus on the problem of finding an optimal design from a set of fixed designs and finding an optimal subset of a given set of sampling locations. As there are many different variables to measure, such as chemical, physical and biological measurements at each location, designs are derived from models based on different types of response variables: continuous, counts and proportions. We apply the methodology to a synthetic example and the Lake Eacham stream network on the Atherton Tablelands in Queensland, Australia. We show that the optimal designs depend very much on the choice of utility function, varying from space filling to clustered designs and mixtures of these, but given the utility function, designs are relatively robust to the type of response variable.     

Field Application of a Renewable Constructed Wetland Substrate for Phosphorus Removal1

Rosenquist, Shawn E., W. Cully Hession, Matthew J. Eick, and David H. Vaughan, 2011. Field Application of a Renewable Constructed Wetland Substrate for Phosphorus Removal. Journal of the American Water Resources Association (JAWRA) 47(4):800‐812. DOI: 10.1111/j.1752‐1688.2011.00557.x Abstract: Phosphorus (P) is typically the best target to prevent eutrophication in freshwater, a biological process associated with water quality degradation. Constructed wetlands (CW) and other practices that include P removal by sorption processes in substrates can provide economical treatment of stormwater, but have limitations (e.g., large land requirements, loss of removal over time, lack of P recovery). Over the last three years, a multi‐study research program addressed these limitations with a new P management concept. This concept minimizes CW size with a rejuvenation cycle (or rejuvenation) that renews P‐sorption capacity in the CW substrates and enables P recovery for productive use. This study, conducted in Blacksburg, Virginia (July‐September 2009), tested the efficacy of rejuvenation in the field. Methods included replicate cells of two sand substrates monitored for P removal during prerejuvenation and postrejuvenation filtration runs. One substrate contained cast iron filings as a repository for sorption capacity. Results support the following conclusions: (1) P removal is likely dependent on multiple factors including influent P concentration, previous substrate/solution equilibrium, pH, and time; (2) rejuvenation is capable of releasing P adsorbed during stormwater filtration; (3) inclusion of cast iron in substrate promotes additional P removal and enables further removal after rejuvenation; but (4) inclusion of cast iron may limit release of P during rejuvenation.     

Modelling the responses of wildlife to human disturbance: An evaluation of alternative management scenarios for black-crowned night-herons

The impact of anthropogenic disturbance on wildlife is increasing becoming a source of concern as the popularity of outdoor recreation rises. There is now more pressure on site managers to simultaneously ensure the continued persistence of wildlife and provide recreational opportunities. Using ‘Simulation of Disturbance Activities’, a model designed to investigate the impact of recreational disturbance on wildlife, we demonstrate how a simulation modelling approach can effectively inform such management decisions. As an example, we explored the implications of various design and management options for a proposed recreational area containing a historic breeding bird colony. By manipulating the proximity, orientation and intensity of recreation, we were able to evaluate the impact of recreational activities on the behaviour of black-crowned night-heron nestlings (Nycticorax nycticorax). Using a classification and regression tree (CART) procedure to analyse simulation output, we explored the dynamics of multiple strategies in concert. Our analysis revealed that there are inherent advantages in implementing multiple strategies as opposed to any single strategy. Nestlings were not disturbed by recreation when bird-watching facility placement (proximity and orientation) and type were considered in combination. In comparison, proximity alone only led to a <10% reduction in disturbance. Thus we demonstrate how simulation models based on customised empirical data can bridge the gap between field studies and active management, enabling users to test novel management scenarios that are otherwise logistically difficult. Furthermore, such models potentially have broad application in understanding human-wildlife interactions (e.g. exploring the implications of roads on wildlife, probability of bird strikes around airports, etc.). They therefore represent a valuable decision-making tool in the ecological design of urban infrastructures.     

Female lizards discriminate between potential reproductive partners using multiple male traits when territory cues are absent

Female choice can powerfully influence the evolution of male phenotypes. In territorial species, it is challenging to determine the targets of female choice because male traits (e.g., behavior and morphology) are often correlated with territory. We sought to elucidate if and how females specifically evaluate male traits in a territorial species. In this study, we presented female fence lizards, Sceloporus undulatus, with two potential mates to examine mate choice in the absence of territory cues. Females associated more with males possessing better body condition, longer heads, and wider throat badges, and that performed more shudder behavior, which females responded to by approaching shuddering males and performing push-ups. A post hoc decision tree analysis suggests that the strongest predictor of female association was an overall quality index that incorporates all of these traits, rather than individual traits. Male snout–vent length, head width, abdominal badge width, and push-up behavior did not affect female association. Further research on why these traits, which are known to correlate with fitness, do not appear to be used by females when selecting mates would improve our understanding of the evolution of male traits. Our study reveals that females of this territorial species possess the ability to use multiple male traits interactively to make fitness-relevant mate choice decisions in the absence of direct territory cues.     

MACROSCALE HYDROLOGIC MODELING FOR REGIONAL CLIMATE ASSESSMENT STUDIES IN THE SOUTHEASTERN UMTED STATES1

ABSTRACT: A macroscale hydrologic model is developed for regional climate assessment studies under way in the southeastern United States. The hydrologic modeling strategy is developed to optimize spatial representation of basin characteristics while maximizing computational efficiency. The model employs the “grouped response unit” methodology, which follows the natural drainage pattern of the area. First order streams are delineated and their surface characteristics are tested so that areas with statistically similar characteristics can be combined into larger computational zones for modeling purposes. Hydrologic response units (HRU) are identified within the modeling units and a simple three‐layer water balance model, Soil and Water Assessment Tool (SWAT), is executed for each HRU. The runoff values are then convoluted using a triangular unit hydrograph and routed by Muskingum‐Cunge method. The methodology is shown to produce accurate results relative to other studies, when compared to observations. The model is used to evaluate the potential error in hydrologic assessments when using GCM predictions as climatic input in a rainfall‐runoff dominated environment. In such areas, the results from this study, although limited in temporal and spatial scope, appear to imply that use of GCM climate predictions in short term quantitative analyses studies in rainfall‐runoff dominated environments should proceed with caution.