Application of the ELOHA Framework to Regulated Rivers in the Upper Tennessee River Basin: A Case Study

In order for habitat restoration in regulated rivers to be effective at large scales, broadly applicable frameworks are needed that provide measurable objectives and contexts for management. The Ecological Limits of Hydrologic Alteration (ELOHA) framework was created as a template to assess hydrologic alterations, develop relationships between altered streamflow and ecology, and establish environmental flow standards. We tested the utility of ELOHA in informing flow restoration applications for fish and riparian communities in regulated rivers in the Upper Tennessee River Basin (UTRB). We followed the steps of ELOHA to generate univariate relationships between altered flows and ecology within the UTRB. By comparison, we constructed multivariate models to determine improvements in predictive capacity with the addition of non-flow variables. We then determined whether those relationships could predict fish and riparian responses to flow restoration in the Cheoah River, a regulated system within the UTRB. Although ELOHA provided a robust template to construct hydrologic information and predict hydrology for ungaged locations, our results do not suggest that univariate relationships between flow and ecology (step 4, ELOHA process) can produce results sufficient to guide flow restoration in regulated rivers. After constructing multivariate models, we successfully developed predictive relationships between flow alterations and fish/riparian responses. In accordance with model predictions, riparian encroachment displayed consistent decreases with increases in flow magnitude in the Cheoah River; however, fish richness did not increase as predicted 4 years after restoration. Our results suggest that altered temperature and substrate and the current disturbance regime may have reduced opportunities for fish species colonization. Our case study highlights the need for interdisciplinary science in defining environmental flows for regulated rivers and the need for adaptive management approaches once flows are restored.     

Assessing Calibration Uncertainty and Automation for Estimating Evapotranspiration from Agricultural Areas Using METRIC

Agricultural irrigation accounts for a large fraction of the total water use in the western United States. The Mapping Evapotranspiration at high Resolution with Internalized Calibration (METRIC) remote sensing energy balance model is being used to estimate historical agricultural water use in western Nevada to evaluate basin‐wide water budgets. Each METRIC evapotranspiration (ET) estimate must be calibrated by a trained user, which requires some iterative time investment and results in variation in ET estimates between users. An automated calibration algorithm for the METRIC model was designed to generate ET estimates comparable to those from trained users by mimicking the manual calibration process. Automated calibration allows for rapid generation of METRIC ET estimates with minimal manual intervention, as well as uncertainty and sensitivity analysis of the model. The variation in ET estimates generated by the automated calibration algorithm was found to be similar to the variation in manual ET estimates. Results indicate that uncertainty was highest for fields with low ET levels and lowest for fields with high ET levels, with a seasonal mean uncertainty of approximately 5% for all fields. In addition, in a blind comparison, automated daily and seasonal ET estimates compared well with flux tower measurement ET data at multiple sites. Automated methods can generate first‐order ET estimates that are similar to time intensive manual efforts with less time investment.     

Neighborhood analyses of canopy tree competition along environmental gradients in New England forests.

We use permanent-plot data from the USDA Forest Service's Forest Inventory and Analysis (FIA) program for an analysis of the effects of competition on tree growth along environmental gradients for the 14 most abundant tree species in forests of northern New England, USA. Our analysis estimates actual growth for each individual tree of a given species as a function of average potential diameter growth modified by three sets of scalars that quantify the effects on growth of (1) initial target tree size (dbh), (2) local environmental conditions, and (3) crowding by neighboring trees. Potential growth of seven of the 14 species varied along at least one of the two environmental axes identified by an ordination of relative abundance of species in plots. The relative abundances of a number of species were significantly displaced from sites where they showed maximum potential growth. In all of these cases, abundance was displaced to the more resource-poor end of the environmental gradient (either low fertility or low moisture). The pattern was most pronounced among early successional species, whereas late-successional species reached their greatest abundance on sites where they also showed the highest growth in the absence of competition. The analysis also provides empirical estimates of the strength of intraspecific and interspecific competitive effects of neighbors. For all but one of the species, our results led us to reject the hypothesis that all species of competitors have equivalent effects on a target species. Most of the individual pairwise interactions were strongly asymmetric. There was a clear competitive hierarchy among the four most shade-tolerant species, and a separate competitive hierarchy among the shade-intolerant species. Our results suggest that timber yield following selective logging will vary dramatically depending on the configuration of the residual canopy, because of interspecific variation in the magnitude of both the competitive effects of different species of neighbors and the competitive responses of different species of target trees to neighbors. The matrix of competition coefficients suggests that there may be clear benefits in managing for specific mixtures of species within local neighborhoods within stands.     

Environmental Dependency of Inbreeding Depression: Implications for Conservation Biology

Inbreeding depression is environmentally dependent, such that a population may suffer from inbreeding depression in one environment but not another. We examined the phenotypic responses of 35 inbred ( F = 0.672) lineages of the red flour beetle Tribolium castaneum in two different climatic environments. We found a significant environmental effect on males but not females. More important, we found that the rank fitness order of lineages differs between environments; lineages of high fitness in one environment may have low fitness in another environment. This change in rank is evident in a significant genotype-by-environment interaction for inbreeding depression for both females and males. These results suggest that even if we know the average environmental effect of inbreeding depression in a population, for any particular lineage measurements of inbreeding depression in one environment may not predict the level of inbreeding depression in another environment. Conservation biologists need to be aware of the environmental dependency of inbreeding depression when planning wildlife refuges or captive propagation programs for small populations. Ideally, captive propagation programs should maintain separate lineages for release efforts. Refuge design programs should consider maintaining a range of habitat types.     

Ranking countries for minerals exploration

This paper presents the results of a survey of multinational mining companies pertaining to the ranking of countries for non-fuel minerals exploration in the early 1990s. It ranks countries in order of greatest exploration interest in the early 1990s, as well as countries that have geologic potential but unacceptable investment climates. It provides a list of priority commodities for exploration, the criteria for exploration levels, critical and negotiable factors in selecting countries for exploration, and the investment climate ratings of countries where exploration is probable in the early 1990s. The results of the survey indicate that major minerals exploration activities are concentrated in a small number of countries. Political and economic reforms around the world should increase the number of countries receiving active private sector minerals exploration in the 1990s.     

Indoor/outdoor connections exemplified by processes that depend on an organic compound's saturation vapor pressure

Outdoor and indoor environments are profitably viewed as parts of a whole connected through various physical and chemical interactions. This paper examines four phenomena that share a dependence on vapor pressure—the extent to which an organic compound in the gas phase sorbs on airborne particles, sorbs on surfaces, sorbs on particles collected on a filter or activates trigeminal nerve receptors. It also defines a new equilibrium coefficient for the partitioning of organic compounds between an airstream and particles collected by a filter in that airstream. Gas/particle partitioning has been studied extensively outdoors, but sparingly indoors. Gas/surface partitioning occurs primarily indoors while gas/filter partitioning occurs at the interface between outdoors and indoors. Activation of trigeminal nerve receptors occurs at the human interface. The logarithm of an organic compound's saturation vapor pressure correlates in a linear fashion with the logarithms of equilibrium coefficients characteristic of each of these four phenomena. Since, to a rough approximation, the log of an organic compound's vapor pressure scales with its molecular weight, molecular weight can be used to make first estimates of the above processes. For typical indoor conditions, only larger compounds with lower-saturation vapor pressures (e.g., tetracosane, pentacosane, or di-2-ethylhexyl phthalate) have airborne particle concentrations comparable to or larger than gas phase concentrations. Regardless of a compound's vapor pressure, the total mass sorbed on indoor airborne particles is quite small compared to the total sorbed on indoor surfaces, reflecting the large difference in surface areas between particles within a room and surfaces within a room. If the actual surface areas are considered, accounting for roughness and porosity, the surface concentration of organics sorbed on typical airborne particles appears to be comparable to the surface concentration of organics sorbed on indoor carpets, walls and other materials (based on data from several studies in the literature). Mirroring the importance of phase distributions outdoors, an organic compound's indoor lifetime, fate and even health impacts depend on its distribution between phases and among surfaces.     

Population biology of White-crowned Sparrows: Residence time and local movements of juveniles

Summary A field study of the ranging behavior of post-fledging White-crowned Sparrows (Zonotrichia leucophrys nuttalli) was carried out in undisturbed natural habitat in the Point Reyes National Seashore, Marin Co., California, USA. Forty-three first-brood juveniles, with tail feathers still growing, were banded at an estimated average age of 27 days and re-trapped an average of an additional 24 days for a total minimum time in residence in the immediate natal area of 51 days (Table 1).The distance from the site of first capture to subsequent recapture sites was about 60 m until age 35 days; then the distance increased to about 250 m by age 50 days (Fig. 2). These data indicate that the average juvenile White-crowned Sparrow completes at least the first 50 days of life in its natal area. Experimental work on song ontogeny has previously demonstrated that the sensitive period for song learning ends at about 50 days. Hence, young in our study population probably learn their natal dialect prior to any major dispersal movements. The correspondence between residence time and song learning would have the consequence of perpetuating song dialects as geographically structured populations.     

红树林呼吸根上生物固氮作用的初步观测研究

在热带海洋环境中,红树林是具有较高生产力的生态系[1,2].通常认为,红树林湿地区域可为毗连的沿岸水域和相关的生物群落生境提供有机物和无机物[3～5].尽管在红树林区域中具有很高的生产率,但红树林的树木一般是生长在营养比较贫瘠的热带地区.