The United States Clean Water Act (CWA; 1972, and as amended, U.S. Code title 33, sections 1251-1387) provides the long-term, national objective to "restore and maintain the ... biological integrity of the Nation's waters" (section 1251). However, the Act does not define the ecological components, or attributes, that constitute biological integrity nor does it recommend scientific methods to measure the condition of aquatic biota. One way to define biological integrity was described over 25 years ago as a balanced, integrated, adaptive system. Since then a variety of different methods and indices have been designed and applied by each state to quantify the biological condition of their waters. Because states in the United States use different methods to determine biological condition, it is currently difficult to determine if conditions vary across states or to combine state assessments to develop regional or national assessments. A nationally applicable model that allows biological condition to be interpreted independently of assessment methods will greatly assist the efforts of environmental practitioners in the United States to (1) assess aquatic resources more uniformly and directly and (2) communicate more clearly to the public both the current status of aquatic resources and their potential for restoration. To address this need, we propose a descriptive model, the Biological Condition Gradient (BCG) that describes how 10 ecological attributes change in response to increasing levels of stressors. We divide this gradient of biological condition into six tiers useful to water quality scientists and managers. The model was tested by determining how consistently a regionally diverse group of biologists assigned samples of macroinvertebrates or fish to the six tiers. Thirty-three macroinvertebrate biologists concurred in 81% of their 54 assignments. Eleven fish biologists concurred in 74% of their 58 assignments. These results support our contention that the BCG represents aspects of biological condition common to existing assessment methods. We believe the model is consistent with ecological theory and will provide a means to make more consistent, ecologically relevant interpretations of the response of aquatic biota to stressors and to better communicate this information to the public.

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Recent studies of marine invertebrates and fish have suggested that lower and upper critical temperatures (CT(min) and CT(max)) are coupled by a common mechanism: oxygen and capacity limitation of thermal tolerance (OCLT). Using thermolimit respirometry, we tested the predictions of this theory for terrestrial arthropods by measuring maxima and minima for both critical temperatures and metabolic rate in two arthropods, the isopod Porcellio scaber and the beetle Tenebrio molitor, at 40%, 21%, 10% and 2.5% ambient O(2). Critical temperatures were identified as particular points on both activity and traces in four ways. In the first two instances, we identified the inflection points in regressions of absolute difference sum (ADS) residuals calculated for activity (aADS) and (VI), respectively. In the third, we visually identified the lowest point before the post-mortal peak in CO(2) release (PMV). Finally, we pinpointed the sudden drop in at death, where fell outside the 95% confidence intervals of the 5 min period immediately preceding the drop-off (CI). Minimum and maximum metabolic rates were determined using CO(2) traces, and the temperatures corresponding to these identified as T(MetMin) and T(MetMax). For both species, ambient oxygen concentration did not influence CT(min), minimum metabolic rate, or T(MetMin). By contrast, severe hypoxia (2.5% O(2)) caused a 6.9 degrees C decline in activity-based CT(max) for T. molitor and a 10.6 degrees C decline for P. scaber, relative to normoxia (21% O(2)). The magnitude of this decrease differed between methods used to estimated critical thermal limits, highlighting the need for a standard method to determine these endpoints during thermolimit respirometry. Maximum metabolic rate also declined with decreasing ambient oxygen in both species. The combination of increasing metabolic rate and oxygen limitation affected upper thermal limits in these arthropods only in severe hypoxia (2.5% O(2)). In both species, CT(min) and CT(max) responded differently to oxygen limitation, suggesting that this is not a common mechanism coupling upper and lower limits in terrestrial arthropods.

ABSTRACT. Indigenous peoples now engage with many decentralized approaches to environmental management that offer opportunities for integration of Indigenous Ecological Knowledge (IEK) and western science to promote cultural diversity in the management of social-ecological system sustainability. Nevertheless, processes of combining IEK with western science are diverse and affected by numerous factors, including the adaptive co-management context, the intrinsic characteristics of the natural resources, and the governance systems. We present a typology of Indigenous engagement in environmental management, derived through comparative analysis of 21 Australian case studies, and consider its implications for the integration of IEK with western science. Sociological and rational choice institutionalism underpin our analytical framework, which differentiates on three axes: (1) power sharing, incorporating decision making, rules definition, resource values and property rights; (2) participation, incorporating participatory processes, organizations engaged, and coordination approaches; (3) intercultural purpose, incorporating purposes of environmental management, Indigenous engagement, Indigenous development and capacity building. Our typology groups engagement into four types: Indigenous governed collaborations; Indigenous-driven cogovernance; agency-driven co-governance; and agency governance. From our analysis of manifestations of knowledge integration across the types, we argue that Indigenous governance and Indigenous-driven co-governance provides better prospects for integration of IEK and western science for sustainability of social-ecological systems. Supporting Indigenous governance without, or with only a limited requirement for power sharing with other agencies sustains the distinct Indigenous cultural purposes underpinning IEK, and benefits knowledge integration. We conclude by advocating that the typology be applied to test its general effectiveness in guiding practitioners and researchers to develop robust governance for Indigenous knowledge integration in environmental management.

Social values are receiving increased attention in natural resource management policy and practice, and the notion of cultural values has recently emerged, particularly in relation to water resources. Philosophers, environmental policy analysts and others with an interest in environmental valuation have critically analysed value concepts and theories. A popular focus is the commonly 'bipolar' character of value construed as either an intrinsic or utilitarian concept. This paper focuses on the treatment of Indigenous values in contemporary water resource management. The Daly River region of the Northern Territory is undergoing increased agricultural intensification. A 12 month planning exercise sought to integrate social, economic, environmental and cultural values into decisions about land use and water extraction. Separate treatment of Indigenous and non-Indigenous social values compounded the reification of Aboriginal 'cultural values' which were perceived largely within the confines of a cultural heritage paradigm. The heritage paradigm and other common influential theories of value focus on objects, entities and places at the expense of recognition and valuation of relationships, processes and connections between social groups, people and place, and people and non-human entities.

River flows connect people, places, and other forms of life, inspiring and sustaining diverse cultural beliefs, values, and ways of life. The concept of environmental flows provides a framework for improving understanding of relationships between river flows and people, and for supporting those that are mutually beneficial. Nevertheless, most approaches to determining environmental flows remain grounded in the biophysical sciences. The newly revised Brisbane Declaration and Global Action Agenda on Environmental Flows (2018) represents a new phase in environmental flow science and an opportunity to better consider the co-constitution of river flows, ecosystems, and society, and to more explicitly incorporate these relationships into river management. We synthesize understanding of relationships between people and rivers as conceived under the renewed definition of environmental flows. We present case studies from Honduras, India, Canada, New Zealand, and Australia that illustrate multidisciplinary, collaborative efforts where recognizing and meeting diverse flow needs of human populations was central to establishing environmental flow recommendations. We also review a small body of literature to highlight examples of the diversity and interdependencies of human-flow relationships—such as the linkages between river flow and human well-being, spiritual needs, cultural identity, and sense of place—that are typically overlooked when environmental flows are assessed and negotiated. Finally, we call for scientists and water managers to recognize the diversity of ways of knowing, relating to, and utilizing rivers, and to place this recognition at the center of future environmental flow assessments.This article is categorized under:Water and Life > Conservation, Management, and AwarenessHuman Water > Water GovernanceHuman Water > Water as Imagined and Represented

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We measured the field metabolic rate (FMR) and water influx rate (WIR) of the largest species of bird, the Ostrich (Struthio camelus), which lives in the Namib desert, one of the driest regions on earth. Along with doubly—labeled water (DLW) measurements of FMR and WIR, we examined the availability of plants in various habitats, the plants selected by Ostriches, and the daily activity patterns of these birds. During 6—8 d periods, adult Ostriches (88.25 kg) had an FMR of 18 040 kJ/d, while subadult birds (50.75 kg) metabolized energy at a rate of 15 428 kJ/d. Adult energy expenditure was 26% lower than predicted, but subadults had a FMR nearly equivalent to expectation, suggesting that adults may be more efficient at acquiring resources. Conclusions remain tentative because data for the Ostrich exceed previous data used for allometric equations by almost an order of magnitude. Gravel and stoney plains together accounted for 84% of the study area, whereas washes occupied °1%. Vegetation cover was sparse in all habitats, varying between 7 and 19% in most areas, but comprising °15% along drainage lines. Ostriches foraged on gravel plains nearly 65% of their daytime hours and 25.5% of their day in washes. They consumed a narrow range of green plants with Monechma arenicola, Schmidita kalahariensis, Blepharis spp., Trianthema triquetra, and Dicoma capensis representing the principal items in the diet. From a time—activity budget, Ostriches spent 7.5 h of their 24—h day walking, and roosted at night for 11.5 h. Transport between food patches accounted for 62.2% of FMR while nighttime rest was 19.0%. Preening and other maintenance behaviors were responsible for <1% of the Ostriches' energy budget. Ostriches had a frugal water economy when compared to other nonpasserine birds, with both subadults and adults having lower WIRs than predicted. Values for WIR were higher than allometric predictions based on four other desert birds previously studied, but because Ostriches are two orders of magnitude larger in body mass, firm conclusions await further data. Calculations of the water economy index (WEI), the ration of water influx to FMR (in millilitres of water kilojoule), showed that Ostriches conserved water like smaller desert birds. Four species of desert birds had WEI values averaging 0.16 mL/kJ; values of the Ostrich averaged 0.17 mL/kJ. An itemized water budget suggested that adults did not drink during the periods of observation, while water intake by subadults averaged 729 ml/d. This suggests that adults may have lower minimum water requirements than subadults. Combining available data for FMR and WIR with data for the Ostrich, we constructed new allometric equations that nearly span the entire range of bird size and include 62 species of birds.