National contributions to global ecosystem values

Current conservation templates prioritize biogeographic regions with high intensity ecosystem values, such as exceptional species richness or threat. Intensity-based targets are an important consideration in global efforts, but they do not capture all available opportunities to conserve ecosystem values, including those that accrue in low intensity over large areas. We assess six globally-significant ecosystem values—intact wilderness, freshwater availability, productive marine environments, breeding habitat for migratory wildlife, soil carbon storage, and latitudinal potential for range shift in the face of climate change—to highlight opportunities for high-impact broadly-distributed contributions to global conservation. Nations can serve as a cohesive block of policy that can profoundly influence conservation outcomes. Contributions to global ecosystem values that exceed what is predicted by a nation's area alone, can give rise to countries with the capacity to act as ‘conservation superpowers’, such as Canada and Russia. For these conservation superpowers, a relatively small number of national policies can have environmental repercussions for the rest of the world.     

Effects of initial solute distribution on contaminant availability, desorption modeling, and subsurface remediation

Low permeability regions in which solute movement is governed by diffusion reduce the availability of pollutants for remediation and can function as long-term sources of groundwater contamination. The inherent difficulty in understanding mass transfer from these regions of sequestered contamination is further complicated by unknown solute distributions within the low-permeability regions (sequestering regions). When models are calibrated to reproduce temporal histories of solute release from a sequestering region (desorption), the fitted parameter values are used to infer the physical or chemical characteristics of the media; however, the calibrated parameters also reflect the case-specific initial conditions (i.e., the solute distribution within the sequestering region domain at the onset of desorption). This phenomenon is demonstrated using model simulations of solute diffusion from hypothetical solids with characteristics similar to those of the well studied Borden, Ontario aquifer system. Solute release from the solids is simulated using a batch diffusion model under different initial solute distributions within the solids. The results of these model simulations are used to calibrate parameters of a multiple first-order rate desorption model (MRM) to illustrate how the fitted MRM parameters increase or decrease depending on the initial "aging" of the solids. Further numerical simulations are conducted for a one-dimensional flow system under steady-state and variable-rate hydraulic flushing. These simulations show that although aging reduces desorptive mass flux during early stages of flushing, aged sites have greater desorptive mass flux (greater solute availability) than "freshly" contaminated media during the later stages of remediation. Overall, the results demonstrate why the physicochemical meaning of observed desorption rates cannot be accurately deduced without first understanding the initial solute distribution within the media.     

Application of multiple-population viability analysis to evaluate species recovery alternatives

Population viability analysis (PVA) is a powerful conservation tool, but it remains impractical for many species, particularly species with multiple, broadly distributed populations for which collecting suitable data can be challenging. A recently developed method of multiple-population viability analysis (MPVA), however, addresses many limitations of traditional PVA. We built on previous development of MPVA for Lahontan cutthroat trout (LCT) (Oncorhynchus clarkii henshawi), a species listed under the U.S. Endangered Species Act, that is distributed broadly across habitat fragments in the Great Basin (U.S.A.). We simulated potential management scenarios and assessed their effects on population sizes and extinction risks in 211 streams, where LCT exist or may be reintroduced. Conservation populations (those managed for recovery) tended to have lower extinction risks than nonconservation populations (mean = 19.8% vs. 52.7%), but not always. Active management or reprioritization may be warranted in some cases. Eliminating non-native trout had a strong positive effect on overall carrying capacities for LCT populations but often did not translate into lower extinction risks unless simulations also reduced associated stochasticity (to the mean for populations without non-native trout). Sixty fish or 5–10 fish/km was the minimum reintroduction number and density, respectively, that provided near-maximum reintroduction success. This modeling framework provided crucial insights and empirical justification for conservation planning and specific adaptive management actions for this threatened species. More broadly, MPVA is applicable to a wide range of species exhibiting geographic rarity and limited availability of abundance data and greatly extends the potential use of empirical PVA for conservation assessment and planning.     

Spatial structure of internal Poincaré waves in Lake Michigan

In this paper we examine the characteristics of near-inertial internal Poincaré waves in Lake Michigan (USA) as discerned from field experiments and hydrodynamic simulations. The focus is on the determination of the lateral and vertical structure of the waves. Observations of near-inertial internal wave properties are presented from two field experiments in southern Lake Michigan conducted during the years 2009 and 2010 at Michigan City (IN, USA) and Muskegon (MI, USA), respectively. Spectra of thermocline displacements and baroclinic velocities show that kinetic and potential baroclinic energy is dominated by near-inertial internal Poincaré waves. Vertical structure discerned from empirical orthogonal function analysis shows that this energy is predominantly vertical mode 1. Idealized hydrodynamic simulations using stratifications from early summer (June), mid-summer (July) and fall (September) identify the basin-scale internal Poincaré wave structure as a combination of single- and two-basin cells, similar to those identified in Lake Erie by Schwab, with near-surface velocities largest in the center of the northern and southern basins. Near-inertial bottom kinetic energy is seen to have roughly constant magnitude over large swathes across the basin, with higher magnitude in the shallower areas like the Mid-lake Plateau, as compared with the deep northern and southern basins. The near-bottom near-inertial kinetic energy when mapped appears similar to the bottom topography map. The wave-induced vertical shear across thermocline is concentrated along the longitudinal axis of the lake basin, and both near-bottom velocities and thermocline shear are reasonably explained by a simple conceptual model of the expected transverse variability.     

Using perceptions as evidence to improve conservation and environmental management

The conservation community is increasingly focusing on the monitoring and evaluation of management, governance, ecological, and social considerations as part of a broader move toward adaptive management and evidence‐based conservation. Evidence is any information that can be used to come to a conclusion and support a judgment or, in this case, to make decisions that will improve conservation policies, actions, and outcomes. Perceptions are one type of information that is often dismissed as anecdotal by those arguing for evidence‐based conservation. In this paper, I clarify the contributions of research on perceptions of conservation to improving adaptive and evidence‐based conservation. Studies of the perceptions of local people can provide important insights into observations, understandings and interpretations of the social impacts, and ecological outcomes of conservation; the legitimacy of conservation governance; and the social acceptability of environmental management. Perceptions of these factors contribute to positive or negative local evaluations of conservation initiatives. It is positive perceptions, not just objective scientific evidence of effectiveness, that ultimately ensure the support of local constituents thus enabling the long‐term success of conservation. Research on perceptions can inform courses of action to improve conservation and governance at scales ranging from individual initiatives to national and international policies. Better incorporation of evidence from across the social and natural sciences and integration of a plurality of methods into monitoring and evaluation will provide a more complete picture on which to base conservation decisions and environmental management.     

Carryover aquatic effects on survival of metamorphic frogs during pond emigration.

In organisms with complex life cycles, physiological stressors during early life stages may have fitness-level impacts that are delayed into later stages or habitats. We tested the hypothesis that body size and date of metamorphosis, which are highly responsive to aquatic stressors, influence post-metamorphic survival and movement patterns in the terrestrial phase of an ephemeral pond-breeding frog by examining these traits in two populations of northern red-legged frogs (Rana aurora aurora). To increase variation of body size at metamorphosis, we manipulated food availability for 314 of 1045 uniquely marked tadpoles and estimated the probability that frogs survived and emigrated using concentric rings of drift fencing surrounding ponds and Bayesian capture-recapture modeling. The odds of surviving and emigrating from the ponds to the innermost drift fences, approximately 12 m, increased by factors of 2.20 (95% credibility intervals 1.39-4.23) and 2.54 (0.94-4.91) with each millimeter increase in snout-vent length and decreased by factors of 0.91 (0.85-0.96) and 0.89 (0.80-1.00) with each day's delay in metamorphosis for the two ponds. The odds of surviving and moving to the next ring of fencing, 12 m to approximately 40 m from the ponds, increased by a factor of 1.20 (0.45-4.06) with each millimeter increase in size. Our results demonstrated that body size and timing of metamorphosis relate strongly to the performance of newly metamorphosed frogs during their initial transition into terrestrial habitat. Carryover effects of aquatic stressors that reduce size and delay metamorphosis may have population-level impacts that are not expressed until terrestrial stages. Since changes in both aquatic and terrestrial systems are implicated in many amphibian declines, quantifying both immediate and delayed effects of stressors on demographic rates is critical to sound management.     

Modelling the fate of sulphur-35 in crops. 2. Development and validation of the CROPS-35 model

Gas-cooled nuclear power plants in the UK release sulphur-35 during their routine operation, which can be readily assimilated by vegetation. It is therefore necessary to be able to model the uptake of such releases in order to quantify any potential contamination of the food chain. A model is described which predicts the concentration of (35)S in crop components following an aerial gaseous release. Following deposition the allocation to crop components is determined by an export function from a labile pool, the leaves, to those components growing most actively post exposure. The growth rates are determined by crop growth data, which is also used to determine the concentration. The loss of activity is controlled by radioactive decay only. The paper describes the calibration and the validation of the model. To improve the model, further experimental work is required particularly on the export kinetics of (35)S. It may be possible to adapt such a modelling approach to the prediction of crop content for gaseous releases of (3)H and (14)C from nuclear facilities.     

Particle size relationships at the Fresno Supersite

Aerosol size distributions are presented for a winter intensive study at the Fresno Supersite. The size distributions were consistent with and predictive for continuous PM2.5 measured by beta attenuation. They varied temporally with respect to source type and intensity, with the smallest mean diameters associated with high NOx concentrations during weekday morning rush hours. Conversely, small and large particle and black carbon (BC) concentrations were higher during Sunday and weekday evenings in response to traffic and residential wood combustion emissions. Ambient PM2.5 light scattering (Bsp) was precisely but systematically underestimated during winter, probably because of heating in the sample shelter.     

COMPARISON OF HSPF OUTPUTS USING FTABLES GENERATED WITH FIELD SURVEY AND DIGITAL DATA1

ABSTRACT: The Hydrological Simulation Program‐FORTRAN (HSPF) describes discharge from a stream reach based on function tables (FTABLES) that relate stream stage, surface area, volume, and discharge. For this study, five FTABLE scenarios were compared to assess their effect on daily discharge rates predicted using HSPF. Four “field‐based” FTABLE scenarios were developed using detailed cross section surveys collected at predefined intervals along 14 reaches in the study watershed. A fifth “digital‐based” scenario was developed using digital elevation models (DEMs) and Natural Resource Conservation Service (NRCS) Regional Hydraulic Geometry Curves. The Smirnov k‐sample test was used to compare average daily discharge rates simulated with HSPF using the five FTABLE scenarios. No significant difference in simulated stream discharge was found (p = 0.99) between the five FTABLE scenarios. Additional examination of the four field‐based scenarios revealed that the number of cross sections per stream reach used to generate FTABLES had little effect on the resulting stage discharge relationship. These findings suggest that FTABLES generated using digital data are a viable option when simulating stream discharge with HSPF and that if field data are used to generate FTABLES, using fewer cross sections will not adversely affect simulated discharge predictions.