Multi-scale use of lands providing anthropogenic resources by American Crows in an urbanizing landscape

The conversion of forests and farmlands to human settlements has negative impacts on many native species, but also provides resources that some species are able to exploit. American Crows (Corvus brachyrhynchos), one such exploiter, create concern due to their impact as nest predators, disease hosts, and cultural harbingers of evil. We used various measures of crow abundance and resource use to determine crows’ response to features of anthropogenic landscapes in the Puget Sound region of the United States. We examined land cover and land use composition at three spatial scales: study sites (up to 208 ha), crow home ranges within sites (18.1 ha), and local land cover (400 m²). At the study site and within-site scales crow abundance was strongly correlated with land cover providing anthropogenic resources. In particular, crows were associated with the amount of ‘maintained forest’ cover, and were more likely to use grass and shrub cover than forest or bare soil cover. Although crows did not show a generalized response to an edge variable, they exhibited greater use of patchy habitat created by human settlements than of native forests. Radio-tagged territorial adults used resources within their home ranges relatively evenly, suggesting resource selection had occurred at a larger spatial scale. The land conversion pattern of new suburban and exurban settlements creates the mix of impervious surfaces and maintained vegetation that crows use, and in our study area crow populations are expected to continue to increase. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Relative importance of habitat area and isolation for bird occurrence patterns in a naturally patchy landscape

There is debate among ecologists about whether total habitat area or patch arrangement contributes most to population and/or community responses to fragmented or patchy landscapes. We tested the relative effects of patch area and isolation for predicting bird occurrence in a naturally patchy landscape in the Bear River Mountains of Northern Utah, USA. We selected focal patches (mountain meadows) ranging in elevation from 1,920 to 2,860 m and in size from 0.6 to 182 ha. Breeding birds were sampled in each focal meadow during the summers of 2003 and 2004 using variable-distance point transects. Logistic regression and likelihood-based model selection were used to determine the relationship between likelihood of occurrence of three bird species (Brewer’s sparrow, vesper sparrow, and white-crowned sparrow) and area, isolation, and proximity metrics. We used model weights and model-averaged confidence intervals to assess the importance of each predictor variable. Plots of area versus isolation were used to evaluate complex relationships between the variables. We found that meadow area was the most important variable for explaining occurrence for two species, and that isolation was the most important for the other. We also found that the absolute distance was more appropriate for evaluating isolation responses than was the species-specific proximity metric. Our findings add clarity to the debate between ecologists regarding the relative importance of area and isolation in species responses to patchy landscapes.     

Application of sperm cryopreservation in selective breeding of the Pacific oyster,Crassostrea gigas (Thunberg)

The robustness of Pacific oyster, Crassostrea gigas (Thunberg), sperm cryopreservation in the context of selective breeding based on family lines was investigated. Irrespective of egg density, high fertilization success was achieved with cryopreserved sperm when sperm:egg ratios of 1000:1 to 10 000:1 were used. Variation among replicate runs on the same oyster batches was minimal, indicating that cryopreservation and larval rearing procedures were repeatable. Twenty independent single male–female crosses were made to assess the utility of cryopreserved sperm in selective breeding. The fertility of unfrozen sperm was generally a poor predictor of cryopreserved sperm fertility. Based on D‐larval yields, 17 of the 20 crosses were likely to yield adequate spat for selective breeding (>10⁵ D‐larvae from 1 million eggs), two were marginal (5 × 10⁴ D‐larvae) and one was inadequate (4 × 10³ D‐larvae). An alternative fertilization strategy to improve D‐yield from a given number of sperm was then tested. Fertilizing 10 million eggs at a sperm:egg ratio of 200:1 increased the total D‐yield when compared with fertilizing 1 million eggs at a sperm:egg ratio of 2000:1 for the same male–female pair. We conclude that, despite wide variation in fertility, cryopreserved sperm is useful for family production.     

Loggerhead turtle (Caretta caretta) bycatch in Canadian pelagic longline fisheries: Relative importance in the western North Atlantic and opportunities for mitigation

Little is known about the ecology of loggerhead turtles, Caretta caretta, in Canadian waters. However, Canada's eastern waters off the Scotian Shelf, Georges Bank and Grand Banks appear to be seasonal foraging habitats based on dates and locations where they have been captured as fishery bycatch. Estimates derived from data recorded by the international observer program (IOP) and used for this study suggest that thousands of mostly immature loggerheads have been captured in the Canadian pelagic longline fishery (PLF) in the western North Atlantic since 1999. These data suggest that the PLFs for tuna and swordfish are among the most important causes of incidental capture. Although U.S. and Canadian bycatch estimation methods differ and uncertainty associated with the estimates is high, it is clear from the IOP data that bycatch in the Canadian PLF is substantial and roughly within the same magnitude as that reported for the entire U.S. fleet in the North Atlantic for the same period (1999–2005). Analysis of bycatch observer data from the Canadian PLF and other empirical data suggests that fishing at temperatures below 20 °C using fish rather than squid bait and size-18 circle hooks could reduce loggerhead bycatch and mortality. However, research is needed to identify the best options and their commercial viability. Loggerheads that use Canadian Maritime waters are one of the least studied groups of loggerheads in the world, so systematic long-term studies on the ecology of loggerheads in Canada would help fill important information gaps and assist in developing effective recovery plans for this species.     

Energy and resource consumption of land-based Atlantic salmon smolt hatcheries in the Pacific Northwest (USA)

This paper evaluates the resource and energy requirements of six different types of land-based, hatchery production systems located in the U.S. Pacific Northwest: flow-through with a gravity water supply, flow-through with a pumped water supply, flow-through with pure oxygen, partial reuse system, partial reuse with heating, and a reuse system for the production of Atlantic salmon (Salmo salar) smolts. Key parameters used in the evaluation include direct energy, indirect energy, transportation energy, greenhouse gas emissions, and pollutant discharges.Power (electricity and natural gas) and feed energy accounted for the majority of the required energy for all the rearing option evaluated. The sum of the fixed capital and chemicals components accounted for less than 2–12% of the total energy budget for any rearing option. The energy efficiency (energy output/energy input) of the six options ranges from 0.97% for flow-through with pumped supply to 3.49% for the flow-through with gravity supply. The rearing options with the three highest energy efficiencies were flow-through with gravity supply (3.49%), partial reuse (2.75%), and reuse (2.64%).On a kg of smolt produced basis, the six rearing options showed a wide range in performance. The reuse system had the lowest water (2 m³ kg^− 1) and land (0.13 m² kg^− 1) requirements and the third lowest total energy requirement (288 MJ kg^− 1). The partial reuse system had the second lowest total power requirement (276 MJ kg^− 1), a low land requirement (0.21 m² kg^− 1), and moderate water requirements (33 m³ kg^− 1). The partial reuse with temperature control had the second highest total power requirement (657 MJ kg^− 1) and land and water requirements similar to the partial reuse system without temperature control. The flow-through system with pumped water supply had the highest water (289 m³ kg^− 1), land (2.19 m² kg^− 1), and energy requirements (786 MJ kg^− 1) of any of the rearing options. By comparison, the flow-through system with gravity water supply had the lowest energy requirement (218 MJ kg^− 1), a moderate land requirement (0.78 m² kg^− 1), and a high water requirement (214 m³ kg^− 1). The ranking of the six rearing options based capital and operating costs are likely to be quite different from those based on energy, water, and greenhouse gas emissions.     

一种面向育种家的新型台式棉籽脱绒机

正棉籽酸脱绒会危害育种家人身安全和潜在环境。需要1种无需用酸,能有效去除棉短绒且对棉种萌发无不利影响的脱绒方法。为了优化棉籽机械脱绒流程,美国农业部农业研究中心(USDA-ARS)棉花生产与加工部门(Lubbock,Texas)研发创制了一台棉籽机械脱绒样机(图1,图2)。测试设计了应用7种滚筒衬垫(1种是不用任何研磨材料,其余6种分别采用不同的研磨材料)、1个或2个辊刷"擦     

Root architecture of sorghum genotypes differing in root angles under different water regimes

Plant root architecture offers the potential for increasing soil water accessibility, particularly under water-limited conditions. The objectives of this study were to evaluate the root architecture in two genotypes of sorghum (Sorghum bicolor (L.) Moench) differing in root angles and to assess the influence of different deficit irrigation regimes on root architecture. The response of two sorghum genotypes, ‘Early Hegari-Sart’ (EH; steep root angle) and ‘Bk7’ (shallow root angle) to four irrigation treatments was investigated in two replicated outdoor studies using large pots. The results indicated that EH possessed steeper brace and crown root angles, fewer brace roots, greater root biomass, and root length density than Bk7 at deeper soil depths (i.e., 15–30 and 30–45 cm) compared with a shallower depth (i.e., 0–15 cm). Across the soil profile, EH had greater root length density and length of roots of small diameter (<1 mm) than Bk7. Accordingly, EH showed more rapid soil-water capture than Bk7. Different levels of irrigation input greatly affected root architecture. Severe deficit irrigation (25% of full crop transpiration throughout the season) increased the angle and number of crown roots, root biomass, and root length density compared with 75 and 100% of full crop transpiration treatments. Consequently, root system architecture can be effectively manipulated through both genotypic selection and irrigation management to ensure optimal performance under different levels of soil available water.     

Comparative energy and economic analyses of conventional and System of Rice Intensification (SRI) methods of rice production in Thai Nguyen Province,Vietnam

The consumption of energy inputs in agricultural production has been increasing rapidly during the past decades. However, given the limitations and costs of non-renewable energy, increasing production while using the least energy possible has become a major concern of most nations. Prompted by this concern, we conducted a face-to-face survey of 90 farming households in Thai Nguyen Province, Vietnam, to find out how energy is being used in agriculture and, specifically, in their rice production. Through analysis of energy input–output balances, combined with economic efficiency analysis, a comparison was made of conventional and SRI methods of rice production. The study found that applying the SRI method can save around 23% of energy inputs, while increasing energy outputs by 11%. Economic benefits per hectare also rise by more than 8 million dong (USD 364) compared to those under the conventional cultivation system. The study also showed conflicts between the energy and economic balances for manual compared with machine ploughing operations. This study contributes to providing an overview of energy consumption in rice cultivation at the household level. Its findings can help stakeholders to assess current policies and make better decisions on the uses of energy in agricultural production. In addition, the comprehensive approach taken here to analysing energy use and efficiency could expand the analysis and comparison of energy uses at sectoral or activity level—still a new field in Vietnam and many other countries.     

Energy Boom and Gloom? Local Effects of Oil and Natural Gas Drilling on Subjective Well‐Being

Prior to the precipitous drop in oil prices in 2014, the U.S. had experienced a substantial increase in oil and natural gas extraction due to technological advancements including horizontal drilling and hydraulic fracturing. This increased energy development likely created both benefits and costs, but the net effects for local residents are not well understood. This paper examines the effects of conventional and horizontal oil and natural gas drilling in Texas on subjective assessments of life‐satisfaction and bad mental health days for nearby residents. Horizontal drilling has statistically significant deleterious effects on well‐being, but the effects are driven by the Dallas‐Fort Worth (DFW) metropolitan area, an area with both very high levels of horizontal drilling and a large urban population.     

Assessing wild bees in perennial bioenergy landscapes: effects of bioenergy crop composition,landscape configuration,and bioenergy crop area

Context

Wild bee populations are currently under threat, which has led to recent efforts to increase pollinator habitat in North America. Simultaneously, U.S. federal energy policies are beginning to encourage perennial bioenergy cropping (PBC) systems, which have the potential to support native bees.

Objectives

Our objective was to explore the potentially interactive effects of crop composition, total PBC area, and PBC patches in different landscape configurations.

Methods

Using a spatially-explicit modeling approach, the Lonsdorf model, we simulated the impacts of three perennial bioenergy crops (PBC: willow, switchgrass, and prairie), three scenarios with different total PBC area (11.7, 23.5 and 28.8% of agricultural land converted to PBC) and two types of landscape configurations (PBC in clustered landscape patterns that represent realistic future configurations or in dispersed neutral landscape models) on a nest abundance index in an Illinois landscape.

Results

Our modeling results suggest that crop composition and PBC area are particularly important for bee nest abundance, whereas landscape configuration is associated with bee nest abundance at the local scale but less so at the regional scale.

Conclusions

Strategies to enhance wild bee habitat should therefore emphasize the crop composition and amount of PBC.