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Macrophytes represent a functional compartment that plays multiple and fundamental ecological roles in aquatic environments. They are linked with the other compartments of hydrosystems, both abiotic and biotic, which gives them the ability to integrate environmental conditions and reflect the trophic state of watercourses. Nevertheless, macrophytes in Moroccan rivers have been rarely studied. Thus, the main objective of the present work is to study these plants by determining the environmental factors that control their presence and distribution in the watercourses of the upper Oum Er‐rbia basin (Middle Atlas Morocco). From June 2018 to June 2019, 14 sites spread over five rivers were monitored monthly to describe macrophytic communities and investigate their ecological determinism. We used a principal component analysis to establish each river's typology and a detrended correspondence analysis to explore macrophyte assemblages. Canonical correspondence analysis was used to determine the hydrochemical parameters of water that govern the development and distribution of macrophyte species in the upper Oum Er‐rbia basin. The Amengous river stands out from the other surveyed rivers for its exceptional richness of macrophytic species. This richness is often associated with the enrichment of the aquatic environment by nitrogen and phosphate inputs. Furthermore, in some rivers, such as Oum Er‐rbia, nutrient enrichment plays a secondary function in comparison to the hydromorphological descriptors that tend to be more important for macrophyte composition and distribution. [ABSTRACT FROM AUTHOR]

The general characteristics of underground waters of Nakhchivan Autonomous Republic, their prospects of use and main eco-chemical characteristics are highlighted in the article. The practical and theoretical problems of the hydrogeology of the autonomous republic, the laws of distribution of underground water, the formation of its chemical composition, and its usefulness are considered. Groundwater of the area is characterized by its geographical, geological, physical-chemical and ecological qualities. Studying and efficient use of water resources is one of the important tasks in the integrated system of the environment, because they are the main source of water supply for industry, agriculture, communal economy and the population. In connection with this, there is a need to study the hydro-ecological condition of the water supply of the regions in the autonomous republic, to assess the ecological safety of underground water sources. The eco-chemical properties of existing underground waters in the autonomous republic were comparatively analyzed according to the values of general pollution coefficients for the territory. [ABSTRACT FROM AUTHOR]

Water bodies of the delta part of the Lower Volga are extremely important for preservation of biodiversity as feeding and breeding grounds for valuable fish species, including sturgeon species. Meanwhile, the anthropogenic load on these water ecosystems is increasing alongside the growth of oil and gas industry. Thus, the aim of this study is to dynamically assess the pollution of water bodies of the prime grade of fishery importance with petroleum products throughout 2014-2018. The objects of this study are the water bodies exposed to anthropogenic impact of both operating enterprises and formerly active industrial facilities. The content of petroleum products in the samples of water and benthos deposits was defined in accredited laboratories as prescribed by Federal Environment Protection Regulatory Documents (PND F) 14.1:2:4.128-98 and 16.1:2.2.22-98. According to the results of the study, it was found that the content of petroleum products in water exceeds the maximum permitted concentrations (MPC) in all monitored sites, its highest value is 4.2 times the MPC in Kizan River in the vicinity of Sokolovskie Neftyanye Yamy (Sokolovsky Oil Pits), a formerly active industrial facility. Here, the maximum level of pollution of benthos deposits with petroleum products (18719.3 mg kg-1) was recorded, and, as a consequence, the degradation of zoobenthos diversity with oligochaeta remaining its only representative was observed.

Water bodies of the delta part of the Lower Volga are extremely important for preservation of biodiversity as feeding and breeding grounds for valuable fish species, including sturgeon species. Meanwhile, the anthropogenic load on these water ecosystems is increasing alongside the growth of oil and gas industry. Thus, the aim of this study is to dynamically assess the pollution of water bodies of the prime grade of fishery importance with petroleum products throughout 2014-2018. The objects of this study are the water bodies exposed to anthropogenic impact of both operating enterprises and formerly active industrial facilities. The content of petroleum products in the samples of water and benthos deposits was defined in accredited laboratories as prescribed by Federal Environment Protection Regulatory Documents (PND F) 14.1:2:4.128-98 and 16.1:2.2.22-98. According to the results of the study, it was found that the content of petroleum products in water exceeds the maximum permitted concentrations (MPC) in all monitored sites, its highest value is 4.2 times the MPC in Kizan River in the vicinity of Sokolovskie Neftyanye Yamy (Sokolovsky Oil Pits), a formerly active industrial facility. Here, the maximum level of pollution of benthos deposits with petroleum products (18719.3 mg kg-1) was recorded, and, as a consequence, the degradation of zoobenthos diversity with oligochaeta remaining its only representative was observed. [ABSTRACT FROM AUTHOR]

This paper analyses the resilience of the French territories of Saint-Martin by considering the issue of drinking and sanitary water supply system recovery in the aftermath of hurricane Irma. We understand resilience as a post-disaster recovery process (Reghezza & Rufat 2019). We address responses and coping strategies deployed by the institutions (local and national authorities, network operators, NGOs) as well as by the local communities and individuals. The fieldwork we carried out in Saint-Martin highlights the fact that the combination of institutional and inhabitants’ responses prevented a humanitarian disaster. On one hand, institutional stakeholders were able to implement effective and efficient coping strategies. On the other hand, inhabitants’ vulnerability to freshwater shortage risks was greatly reduced by an individual adaptation, built well upstream of Irma in response to local context. Our study confirms that networks are socio-technical systems embedded in a set of production and consumption practices. In this sense, drinking and sanitary water systems criticality is territorialized and individual resilience is rooted in “ordinary vulnerability”.

The results of the theoretical and experimental research of the original synchronized dualchambered hydromechanical system with indirect regulated valve systems of different structural configuration are shown.

Braking modes with application of hydroshock-absorbers for MECHANISMS OF INCREASED OPERATION SPEED are analyzed. Improvement tasks of hydroshock-absorbers for process equipment are formulated.

Generalized structural and conceptual hydrokinetic analytical models, and technique for developing a mathematical model of multiengined hydromechanical systems are presented.

The footprint of catchment properties on water flow is reflected into hydrological signals, such as stream discharge. Here we demonstrate that it is possible to constrain catchment properties from the spectral analysis of hydrological signals but only when an appropriate transfer function (TF) is used for interpretation. We show that the appropriate theoretical TF, newly derived, is the only one to robustly describe a large diversity of experimental TFs that could be encountered in nature, because it entails the role of diffuse overflow and flow through the vadose zone, which have never been considered in spectral approaches before. The properties that may be estimated are the characteristic time scales of transfer in each compartment (surface, vadose zone, and aquifer) and the flow partitioning between surface and subsurface. We validate our approach by comparing the new and previous theoretical TFs to experimental TFs generated by a physically based distributed hydrological model, for a wide range of properties. The results confirm that without the use of the new TF, the interpretation of observed spectra may often lead to severe misestimations of catchment properties. The potential of the new TF to constrain catchment characteristics is exemplified by analyzing real hydrological signals from two watersheds with distinct behaviors. We finally discuss the broad implications of our findings and how they may contribute to a variety of topics in hydrology, thereby opening the way to a more widespread and robust use of spectral analysis to describe hydrosystems from effective rainfall, river discharge, and piezometric data. Plain Language Summary: Time series of hydrological variables, such as river discharge rates or groundwater levels, are very different from the rainfall signal that feeds continental hydrosystems. In addition, different watersheds undergoing similar climatic conditions do not produce similar hydrological responses. Therefore, deciphering how a climatic signal is altered and retranscribed into hydrological signals is a difficult task. Nevertheless, understanding how hydrosystems react to different time scales of climatic forcing remains an important challenge for water management, as it is key to predicting extreme hydrological events (severe droughts and floods). Here we develop and validate a new approach to study the impact of various hydrological compartments (such as surface waters or subsurface waters) on climatic signal transformation. We use a spectral domain approach, meaning that river discharge, for instance, is not seen as function of time but rather as a function of the various elementary frenquencies that compose the signal. We demonstrate that our new approach favors the interpretation of data in the spectral domain and thereby enhances comprehension of flow processes in response to different time scales of climatic inputs. Key Points: Hydrological responses to climatic forcing can be described more efficiently by new transfer functions (TFs)The new TFs account for flow in three key hydrosystem compartments (surface, vadose zone, and aquifer) to interpret data in the spectral domainThe use of previously derived TFs may lead to severe misestimation of catchment dynamics and properties, like aquifer hydraulic diffusivity [ABSTRACT FROM AUTHOR]

Anthropogenic activities have more than doubled the amount of reactive nitrogen circulating on Earth, creating excess nutrients across the terrestrial-aquatic gradient. These excess nutrients have caused worldwide eutrophication, fundamentally altering the functioning of freshwater and marine ecosystems. Riparian zones have been recognized to buffer diffuse nitrate pollution, reducing delivery to aquatic ecosystems, but nutrient removal is not their only function in river systems. In this paper, we propose a new conceptual framework to test the capacity of riparian corridors to retain, remove, and transfer nitrogen along the continuum from land to sea under different climatic conditions. Because longitudinal, lateral, and vertical connectivity in riparian corridors influences their functional role in landscapes, we highlight differences in these parameters across biomes. More specifically, we explore how the structure of riparian corridors shapes stream morphology (the river's spine), their multiple functions at the interface between the stream and its catchment (the skin), and their biogeochemical capacity to retain and remove nitrogen (the kidneys). We use the nitrogen cycle as an example because nitrogen pollution is one of the most pressing global environmental issues, influencing directly and indirectly virtually all ecosystems on Earth. As an initial test of the applicability of our interbiome approach, we present synthesis results of gross ammonification and net nitrification from diverse ecosystems.

Managing resources in inter-tropical environment has always been a critical issue for the rise and prosperity of complex societies. The socio-ecological system of Naachtun, a large Classic Period Maya city (AD 250-950), lies at the heart of this issue. It will be studied here in the perspective of understanding water and soil variability, which is under climate, environmental and anthropogenic controls. Both the hydrosystem and the agrosystem will be characterized through a systemic and multi-scalar approach, allowing for the study of the evolution, the uses and the management of these resources under the influence of climate and population dynamics. Occupied for nearly one millennia (AD 150-950/1000), the city of Naachtun expanded next to a large humid area (bajo), which clearly played a central role in its creation and development, both for water uses and for its agricultural potential.

The current governance of bodies of water within French territory by "water masses" and "watersheds" is the result of a rich history, both scientific and regulatory. However, it proves unsatisfactory in its failure either to take into account limnological diversity or to integrate the lentic question within a codified approach which is preferentially and partially potamological. Hence, the question arises of the relevance of the spatial perimeters used. A geographical, geosystemical, then regional approach based around ‘water territories' has allowed research and mentalities to develop, but the multiplicity of territories generated constitutes a brake against the questioning of the power of hydraulic engineers. And yet, by fully integrating systemic approaches and those of the social sciences, it is possible to consider malleable forms of regionalization according to the criteria and periods and more appropriate to the objectives of "good water status" which have been set at the European level. The widening of limnological science to cover man-made lakes, ponds and other wetlands (instead of the only referring to lakes) opens new perspectives in the broader context of the role of water within the climatic fluctuations. Thereby gaining a broader understanding of the morphological and spatial diversity of the lentic corpus, it becomes possible to observe both systemic and spatial discontinuities and hence to discuss their origins or palimpsest character. The territorialization of these human-environment-body of water relationships thus produces a new concept, the limnic territory, which aims at being operational.

Copyright of VertigO is the property of La Revue Electronique en Sciences de l'Environnement VertigO and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A model and a code for automated optimum design search are created. They are tested on an existing airplane hydraulic system. The objective function was obtained after mathematical transformation. The optimal parameters of pipelines and hydraulic cylinders were found. The minimal mass of a hydrosystem is the optimization criterion. Adequacy of the model is confirmed by comparing it to the known data. In the framework of modeling an interdisciplinary analysis combining the simulation of mechanical system and simulation of hydraulic system is used. In addition the model uses solid models, which determine the kinematic scheme. The resulting algorithm can be used to solve other problems such as design or modernization of aircraft. [ABSTRACT FROM AUTHOR]

The dynamic behavior of the thermal-cryogenic regime of the hydrosystem of the Vilyui Hydroelectric Power Plant, which was the first to be constructed in a continuous space of permafrost rock, is presented. Features of the evolution of the thermal-moisture regime of the hydrosystem and the role of rockfill in thermal and mass transfer (crogenic) processes in the artificially created combined natural and engineered system are considered. It is established that, despite more than a 50-period of service, the thermal regime of the hydrosystem is in a fixed state and far from the steady state. Thawing of the shoreline abutments of the dam and in the reservoir floor is observed, and it is noted that the thermocryogenic processes seen in the lower rockfill retaining prism and at the base of the dam are both cyclic. The stability indicators of the hydrosystem are within the standards defined by Russian legislative documents. [ABSTRACT FROM AUTHOR]

Generalized structural and conceptual hydrokinetic analytical models, and technique for developing a mathematical model of multiengined hydromechanical systems are presented.

Braking modes with application of hydroshock-absorbers for MECHANISMS OF INCREASED OPERATION SPEED are analyzed. Improvement tasks of hydroshock-absorbers for process equipment are formulated.

The results of the theoretical and experimental research of the original synchronized dualchambered hydromechanical system with indirect regulated valve systems of different structural configuration are shown.

Elucidation of genetic mechanisms underpinning migratory behavior could help predict how changes in genetic diversity may affect future spatiotemporal distribution of a migratory species. This ability would benefit conservation of one such declining species, anadromous Pacific lamprey ( Entosphenus tridentatus). Nonphilopatric migration of adult Pacific lamprey has homogenized population-level neutral variation but has maintained adaptive variation that differentiates groups based on geography, run-timing and adult body form. To investigate causes for this adaptive divergence, we examined 647 adult lamprey sampled at a fixed location on the Columbia River and radiotracked during their subsequent upstream migration. We tested whether genetic variation [94 neutral and adaptive single nucleotide polymorphisms ( SNPs) previously identified from a genomewide association study] was associated with phenotypes of migration distance, migration timing, or morphology. Three adaptive markers were strongly associated with morphology, and one marker also correlated with upstream migration distance and timing. Genes physically linked with these markers plausibly influence differences in body size, which is also consistently associated with migration distance in Pacific lamprey. Pacific lamprey conservation implications include the potential to predict an individual's upstream destination based on its genotype. More broadly, the results suggest a genetic basis for intrapopulation variation in migration distance in migratory species. [ABSTRACT FROM AUTHOR]

Downstream of the confluence with the Allier River, the Middle Loire River is characterized by a fluvial bed with semi-embanked channel. The wooded islands are ubiquitous throughout the river’s landscape, and are areas of active vegetalization in the fluvial bed. The aim of the present paper is to provide an update to the current knowledge of these fluvial forms: their formation and rate of development. Recent development of anabranching in the Loire river is related to the co-evolution of societal uses, and the morphology of the river bed. The main channel of the river has continued to migrate laterally within its area of mobility. This situation has led to the development of large areas of sedimention on the biggest islands, which play a major role in the retention of sediments, and the sedimentary imbalance of the river. The development of anabranching reveals fluvial readjustments, and the islands are excellent bio-geomorphological indicators. Our study provides additional input to current research on the anastomosis of rivers with islands in Western Europe.

Les formations végétales arborées riveraines sont en étroite interaction avec le milieu aquatique environnant. Les conditions hydrodynamiques et morphodynamiques régissent la répartition des communautés végétales et réciproquement la végétation riveraine, par sa présence effective ou par ses apports en débris ligneux grossiers, est elle-même un élément structurel de l'hydrosystème. Ainsi, sa présence complexifie l'habitat aquatique, créant un milieu diversifié propice au développement des communautés biologiques et notamment piscicoles. Elle agit également directement sur la chaîne trophique en injectant dans le système des débris organiques, et indirectement en limitant la production autotrophe par ombrage, en régulant les apports en nutriments et la température. En raison du fort degré d'interconnexion entre le milieu aquatique et le milieu terrestre environnant, il est important d'inclure dans les préoccupations de gestion des hydrosystèmes celle des corridors végétaux sur l'ensemble du réseau hydrographique. Aujourd'hui encore, certains types d'aménagement ne sont pas compatibles avec une gestion piscicole optimale. Une stratégie globale est difficile à envisager, mais quelques recommandations concernant la gestion du corridor végétal des rivières peuvent être proposées.

The Loire river is much less developed and artificialized than other big French rivers. However, its catchment basin planning has been at the heart of significant controversies for the last decades. The opposition between developers and environmental protectors has been strong but profitable insofar as it has been helping the transition from a technician watercourse management method – which prioritizes watercourse control through important developments regardless of their environmental effects – to an environmental management method – which strives to articulate planning while preserving the natural balances existing in hydrosystems. Studying the Loire catchment basin may thus highlights the rise of a new and more environment conscious watercourse management method.

Copyright of Studia Universitatis Cibiniensis. Series Historica is the property of University of Sibiu, Lucian Blaga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper deals the problem of small motions and eigenoscillations of the hydrodynamical system' ideal fluid-barotropic gas' with regard for gravitational and capillary forces. The spectrum structure and the basis property of eigenfunctions are studied. The variational principles for eigenvalues are presented. The theorems of strong solvability of an initial boundary-value problem and the inverse Lagrange's theorem of stability of the hydrosystem are proved. [ABSTRACT FROM AUTHOR]

En Afrique tropicale, de nombreuses études sur la variabilité climatique montrent qu'une tendance à la sécheresse s'est manifestée à partir de la fin des années 1960. Cette sécheresse a affecté aussi l'hydrosystème Mono-Couffo, en Afrique de l'Ouest, avec une persistance remarquable qui s'est répercutée sur les écoulements. Depuis 1988, avec la mise en eau du barrage de Nangbéto, qui coïncide avec une légère reprise pluviométrique dans les années 1990, on assiste à une modification du régime hydrologique du Mono à Athiémé. Les méthodes statistiques appliquées aux données mensuelles de pluie et débit de la période 1961–2000 ont permis de constater que les déficits pluviométriques des décennies 1970 et 1980 ont engendré des déficits de l'écoulement. Mais, avec la légère reprise pluviométrique (2%) de 1988 à 2000, on assiste à un excédent d'écoulement de 37% sur le Mono à Athiémé à régime « artificiel » depuis 1988; et, par contre, pas d'excédent (0,1%) sur le Couffo à Lanta à régime « naturel ». Editeur Z.W. Kundzewicz Citation Amoussou, E., Camberlin, P. et Mahé, G., 2012. Impact de la variabilité climatique et du barrage Nangbéto sur l'hydrologie du système Mono-Couffo (Ouest Afrique). Hydrological Sciences Journal, 57 (4), 805–817. [ABSTRACT FROM PUBLISHER]

Mount Kilimanjaro, the highest mountain in Africa, is a site of exceptional diversity. However, its fragile balance is presently under threat, mainly from hydrological issues. Scientists and politicians have different hypotheses concerning the condition and availability of water on the mountain, thus far without consensus. Some of these hypotheses infer that the local Chagga communities living on Kilimanjaro's slopes are implicated in the overall degradation of natural resources. A major part of the research presented in this paper focuses on the Chagga people's view of their environment. The research uses the Actor in 4 Dimensions (A4D) methodology. This multidisciplinary conceptual model helps one to understand a territory by analysing the relations between individuals (social link) and the relations between humans and no humans (natural link). This paper aims to (1) present the A4D model and its innovative methodology, (2) analyse the stakeholders' dynamics around environmental issues on the mountain and (3) focus on the Chagga's perception of natural resource evolution and management. The A4D results show that the Chagga display a profound attachment to their territory, the forest is the element creating social relations, technical progress can mean social regression, conflicts over natural resources are increasing and hydrological risks on Mount Kilimanjaro are primarily of a social nature. [ABSTRACT FROM AUTHOR]

The tenor in organic matter has been assessed in an urban aquatic ecosystem the Mfoundi River Basin of Cameroon. The double technique of the Biochemical Oxygen Demand (BOD5) and the Oxydability test have been employed in this assessment. The results obtained indicate a high content of organic matter in the watershed with the highest values of BOD 297.5 mg O2 dm-3 and Oxydability 50.255 mg O2 dm-3 observed at the Akeu stream. The spearman correlation coefficient between BOD5 and Oxydability for the seasonal distribution is 0.22 which is positive but not statistically significant due to a high variability of biodegradable and non-biodegradable organic matter present in the river basin. The same value calculated between these organic tests with respect to the sampling sites is negative (-0.15) due probably to their abiotic and biotic heterogeneity. The results reveal a high tenor in organic matter in the hydro-system during the dry season, with a relative reduction during the rainy season, a situation that exposes the population of Yaoundé and its environs to acute pollution which can lead to numerous water related health hazards. [ABSTRACT FROM AUTHOR]

The article explores the use of the Plan for Analyzing and Testing Hypotheses (PATH), created by the National Marine Fisheries Service (NMFS), in studying the salmon populations in the Snake River sub-basin of the Columbia River in Oregon and Idaho. PATH received clear direction from the Implementation Team on management objectives and what hydrosystem actions to analyze. Some of the lessons learned from the successes and failures of PATH include building trust through independent technical facilitation and multiple levels of peer review and clarifying uncertainties by developing common data sets and thorough retrospective analyses of the weight of evidence.

Kisima Ngeda (KN), a spring on the northern margin of saline Lake Eyasi, Tanzania, sustains an Acacia-Hyphaene palm woodland and Typha swamps, while the surrounding vegetation is semi-desert. To study the vegetation changes associated with this spring, which represents a plausible modern analog for the fossil springs documented in the nearby paleoanthropological and archaeological sites of Olduvai Gorge, we analyzed the pollen content of a 43 cm-long sediment core that documents vegetation changes since the last ~1200 years (from cal yrs. C.E. 841 to 2011). Our results show that (1) Hyphaene palms, which require meso-halophytic soil conditions were most abundant in the area of the coring site until cal yrs. C.E. ~1150 when the groundwater supplying the KN spring was likely lower than at present, allowing intrusions of saline lake waters. (2) From cal yrs. C.E. ~1200, a peat began to develop, the palm woodland was replaced by a Mimosaceae woodland, and the increased presence of Typha pollen indicates the presence of more wetlands. (3) From cal yrs. C.E. 1600, the groundwater level of the KN spring increased and reached its highest level in the last 1200 years. (4) Peaks of wetland expansion, which reflect increased groundwater flow and level in response to amplified rainfall in the recharge area (Mt Oldeani, Ngorongoro Highlands), occurred at cal yrs. C.E. ~1200–1400 and ~1650–2011. These outflows of groundwater at Kisima Ngeda were linked to the intensity and frequency of positive Indian Ocean Dipole (IOD) events, which trigger heavy rains in eastern Africa. We conclude that the Kisima Ngeda hydrological system, which has been active for more than 1200 years, responds rapidly to regional climate change driven by changes in the sea surface temperatures (SSTs) of the Indian Ocean. Yet, it is also capable of remaining active during dry intervals as inferred from the Kisima Ngeda record prior to cal yrs. C.E. 1200. Our results support the hypothesis that this type of system helped to maintain Plio-Pleistocene hominin populations and activities in the arid lowlands of the rift on a multi-decennial scale. • Freshwater springs sustain Acacia -palm woodlands near saline Lake Eyasi (N edge). • KN1A pollen record shows Kisima spring woodlands existed since >1200 yrs. • KN1A pollen record infers today is wetter than LIA which was also wetter than MCA. • Fresh groundwater remained easily accessible even during dry periods like MCA. • KN spring likely responds to IOD events and regional precipitation changes. [ABSTRACT FROM AUTHOR]

Observed declines in the Snake River basin salmon stocks, listed under the U.S. Endangered Species Act (ESA), have been attributed to multiple causes: the hydrosystem, hatcheries, habitat, harvest, and ocean climate. Conflicting and competing analyses by different agencies led the National Marine Fisheries Service (NMFS) in 1995 to create the Plan for Analyzing and Testing Hypotheses (PATH), a collaborative interagency analytical process. PATH included about 30 fisheries scientists from a dozen agencies, as well as independent participating scientists and a technical facilitation team. PATH had some successes and some failures in meeting its objectives. Some key lessons learned from these successes and failures were to: (1) build trust through independent technical facilitation and multiple levels of peer review (agency scientists, independent participating scientists and an external Scientific Review Panel); (2) clarify critical uncertainties by developing common data sets, detailed sensitivity analyses, and thorough retrospective analyses of the weight of evidence for key alternative hypotheses; (3) clarify advice to decision makers by using an integrated life cycle model and decision analysis framework to evaluate the robustness of potential recovery actions under alternative states of nature; (4) involve key senior scientists with access to decision makers; (5) work closely with policy makers to clearly communicate analyses in nontechnical terms and provide input into the creation of management alternatives; and (6) recognize the trade-off between collaboration and timely completion of assignments.