Can entropy maximization use functional traits to explain species abundances? A comprehensive evaluation

Entropy maximization (EM) is a method that can link functional traits and community composition by predicting relative abundances of each species in a community using limited trait information. We developed a complementary suite of tests to examine the strengths and limitations of EM and the community-aggregated traits (CATs; i.e., weighted averages) on which it depends that can be applied to virtually any plant community data set. We show that suites of CATs can be used to differentiate communities and that EM can address the classic problem of characterizing ecological niches by quantifying constraints (CATs) on complex trait relationships in local communities. EM outperformed null models and comparable regression models in communities with different levels of dominance, diversity, and trait similarity. EM predicted well the abundance of the dominant species that drive community-level traits; it typically identified rarer species as such, although it struggled to predict the abundances of the rarest species in some cases. Predictions were sensitive to choice of traits, were substantially improved by using informative priors based on null models, and were robust to variation in trait measurement due to intraspecific variability or measurement error. We demonstrate how similarity in species' traits confounds predictions and provide guidelines for applying EM.     

Coral identity underpins architectural complexity on Caribbean reefs

The architectural complexity of ecosystems can greatly influence their capacity to support biodiversity and deliver ecosystem services. Understanding the components underlying this complexity can aid the development of effective strategies for ecosystem conservation. Caribbean coral reefs support and protect millions of livelihoods, but recent anthropogenic change is shifting communities toward reefs dominated by stress-resistant coral species, which are often less architecturally complex. With the regionwide decline in reef fish abundance, it is becoming increasingly important to understand changes in coral reef community structure and function. We quantify the influence of coral composition, diversity, and morpho-functional traits on the architectural complexity of reefs across 91 sites at Cozumel, Mexico. Although reef architectural complexity increases with coral cover and species richness, it is highest on sites that are low in taxonomic evenness and dominated by morpho-functionally important, reef-building coral genera, particularly Montastraea. Sites with similar coral community composition also tend to occur on reefs with very similar architectural complexity, suggesting that reef structure tends to be determined by the same key species across sites. Our findings provide support for prioritizing and protecting particular reef types, especially those dominated by key reef-building corals, in order to enhance reef complexity.     

Flow regimes in gaps within stands of flexible vegetation: laboratory flume simulations

Analyses of results from laboratory flume experiments are presented in which flow within gaps in canopies of flexible, submerged aquatic vegetation simulations is investigated. The aims of the work are (a) to identify the different flow regimes that may be found within such gaps, using Morris’ classical definitions of skimming flow, wake interference flow and isolated roughness flow as a template, (b) to determine the parameter space in which those flow regimes are most consistently delineated, and (c) to provide quantitative measurements of the loci of each flow regime within that parameter space for these experiments. The sedimentary and biological implications of each flow regime are also discussed. The results show that five flow regimes may be identified, expanding on Morris’ original set of three. The five are: (i) skimming flow; (ii) recirculation flow; (iii) boundary layer recovery; (iv) canopy through-flow; and (v) isolated roughness flow, the last being assumed to occur in some cases though it is not directly observed in these experiments. A Reynolds number based on the canopy overflow speed and the gap depth, and the gap aspect ratio are found to be the key parameters that determine these flow regimes, though a Froude number is found to be important for determining bed shear stress, and the length of leaves overhanging the gap from the upstream canopy is found to be important in determining the location of flow recirculation cells within the gap.     

Disaster risk reduction and ‘built‐in’ resilience: towards overarching principles for construction practice

The emerging emphasis on disaster risk reduction has broadened the range of experts whose knowledge must be garnered to resolve complex socio‐technical challenges. This paper examines the role and position of the construction sector for addressing these concerns. Specifically, it examines the recursive nature of practices within the built environment, which can be seen as deeply ingraining fragmented approaches to the development process. These, in turn, render the industry a difficult arena within which to enact structural and cultural change. Based on a wide body of literature on resiliency a set of overarching principles are proffered to help inform efforts to overcome some of the barriers to creating a more resilient built environment. It is argued that these principles offer a point of departure for embedding resilience considerations at both project and institutional levels, although real change would demand challenging some of the conventions that currently underpin construction development.     

Drug markets during the Katrina disaster

PURPOSE: The purpose of this paper is to examine the experiences of poor drug users and sellers who remained in New Orleans during Hurricane Katrina in 2005 to identify their special needs and the unique challenges they present to disaster management. DESIGN/METHODOLOGY/APPROACH: Semi-structured, open-ended interviews were conducted with 119 poor, predominantly African-American, drug users and sellers. Their stories in their own words provide a mosaic of drug-related experiences from the period immediately preceding the storm through evacuation and reveal the motivations behind their behaviors. FINDINGS: Many drug users placed partying, maintaining their habits, and making money ahead of personal safety and evacuation. Drug use and sales led many not to evacuate before the storm, to use drugs in congregate shelters, to avoid shelters, to roam through flooded debris-strewn streets, to loot stores and homes of drug dealers, and to use violence or the threat of violence to achieve their drug-related aims. ORIGINALITY/VALUE: During a disaster, many poor drug users place risks on themselves, their families, their communities and ultimately on rescue workers. The conclusion presents pragmatic and humanitarian guidelines for successfully addressing this additional challenge. The recommendations are consistent with other suggestions concerning the special needs of indigent populations.     

Identification of tetramethylarsonium in rice grains with elevated arsenic content

Tetramethylarsonium has for the first time been identified in a commercially grown food product, rice, constituting up to 5.8% of the total arsenic in the rice.     

How to “walk the talk”: The perspectives of sector staff on implementation of the rural water supply programme in Uganda

Many countries in sub‐Saharan Africa have adopted similar approaches to tackle the challenges of rural water supply, including community‐based management, community participation and the demand‐responsive approach. These are often combined with nationwide programmes of capacity‐building and decentralization. This paper first shows how Uganda has adopted these approaches in its rural water supply programme. Based on Government documents, we construct an organizational framework that illustrates the overall programme and outlines the roles and responsibilities which actors are expected to fulfil. Second, based on interviews with sector staff and a review of Government documents, the paper examines challenges to successfully “walk the talk”; that is, it provides insight into challenges affecting programme implementation. Among numerous difficulties, two key issues are highlighted: local political interference and the weak capacity of local governments. Concerning local political interference, local planning processes need to be reformed so that local politicians commit more strongly to improving water supply. Regarding local government capacity, the Government department responsible for the programme has established eight regional units that provide support to local governments. This promising strategy, combined with more appropriate engagement and the commitment of local politicians, should help to improve the implementation of the rural water supply programme in Uganda.     

Evaluating the efficacy of adaptive management approaches: Is there a formula for success?

Within the field of natural-resources management, the application of adaptive management is appropriate for complex problems high in uncertainty. Adaptive management is becoming an increasingly popular management-decision tool within the scientific community and has developed into two primary schools of thought: the Resilience-Experimentalist School (with high emphasis on stakeholder involvement, resilience, and highly complex models) and the Decision-Theoretic School (which results in relatively simple models through emphasizing stakeholder involvement for identifying management objectives). Because of these differences, adaptive management plans implemented under each of these schools may yield varying levels of success. We evaluated peer-reviewed literature focused on incorporation of adaptive management to identify components of successful adaptive management plans. Our evaluation included adaptive management elements such as stakeholder involvement, definitions of management objectives and actions, use and complexity of predictive models, and the sequence in which these elements were applied. We also defined a scale of degrees of success to make comparisons between the two adaptive management schools of thought. Our results include the relationship between the adaptive management process documented in the reviewed literature and our defined continuum of successful outcomes. Our data suggest an increase in the number of published articles with substantive discussion of adaptive management from 2000 to 2009 at a mean rate of annual change of 0.92 (r2 = 0.56). Additionally, our examination of data for temporal patterns related to each school resulted in an increase in acknowledgement of the Decision-Theoretic School of thought at a mean annual rate of change of 0.02 (r2 = 0.6679) and a stable acknowledgement for the Resilience-Experimentalist School of thought (r2 = 0.0042; slope = 0.0013). Identifying the elements of successful adaptive management will be advantageous to natural-resources managers considering adaptive management as a decision tool.     

The Influence of Loss Aversion on Mountain Bikers’ Behavioral Intentions

Public involvement in management decision making has received increased attention from researchers in recent years. These studies, however, have rarely considered differences in behavior resulting from gains and losses, despite ample evidence that individuals’ behavior is not the same across situations. Individuals are often more sensitive to losses than gains, which research suggests is related to ownership (real or perceived) of the item lost. We present evidence from a within-subjects quasi-experimental design to test whether mountain bikers’ reported intentions differ between gain based and loss based conditions. These data were analyzed using a multi-step repeated measures analysis of variance and repeated measures analysis of covariance. The results suggest that losses are more powerful than gains in motivating public engagement in management decision making. Further, the type of action was also shown to influence behavioral intentions. Additional analyses provide support to the claim that, centrality, used as a proximate measure of ownership, moderates the contextual effects on behavioral intentions. Thus, loss aversion, moderated by ownership, is a plausible explanation of stakeholder involvement.