Projecting future grassland productivity to assess the sustainability of potential biofuel feedstock areas in the Greater Platte River Basin

This study projects future (e.g., 2050 and 2099) grassland productivities in the Greater Platte River Basin (GPRB) using ecosystem performance (EP, a surrogate for measuring ecosystem productivity) models and future climate projections. The EP models developed from a previous study were based on the satellite vegetation index, site geophysical and biophysical features, and weather and climate drivers. The future climate data used in this study were derived from the National Center for Atmospheric Research Community Climate System Model 3.0 ‘SRES A1B’ (a ‘middle’ emissions path). The main objective of this study is to assess the future sustainability of the potential biofuel feedstock areas identified in a previous study. Results show that the potential biofuel feedstock areas (the more mesic eastern part of the GPRB) will remain productive (i.e., aboveground grassland biomass productivity >2750 kg ha^?1 year^?1) with a slight increasing trend in the future. The spatially averaged EPs for these areas are 3519, 3432, 3557, 3605, 3752, and 3583 kg ha^?1 year^?1 for current site potential (2000–2008 average), 2020, 2030, 2040, 2050, and 2099, respectively. Therefore, the identified potential biofuel feedstock areas will likely continue to be sustainable for future biofuel development. On the other hand, grasslands identified as having no biofuel potential in the drier western part of the GPRB would be expected to stay unproductive in the future (spatially averaged EPs are 1822, 1691, 1896, 2306, 1994, and 2169 kg ha^?1 year^?1 for site potential, 2020, 2030, 2040, 2050, and 2099). These areas should continue to be unsuitable for biofuel feedstock development in the future. These future grassland productivity estimation maps can help land managers to understand and adapt to the expected changes in future EP in the GPRB and to assess the future sustainability and feasibility of potential biofuel feedstock areas.     

Information and Communication Technology‐Enabled Low Carbon Technologies

This article outlines the subsector of the information and communication technology (ICT) industry concerned with reducing the economy's environmental impact, dubbed ICT‐enabled low carbon technologies (ICTeLCTs). The article is based on a study funded by United Kingdom (UK) Trade and Investment, a division of the UK Department for Business, Innovation and Skills. ICTeLCTs can be segmented into specialist and generalist operators. Specialists focus on one or two ICT applications to monitor or reduce environmental issues, while generalists supply products and services enabling a firm or a private household to reduce the environmental impact of its activities. The subsector can be further segmented into green ICT, energy management, building management, carbon accounting, waste management, intelligent transport systems (ITSs), and water management. The main factors driving ICTeLCTs include legislation, voluntary environmental standards, corporate social responsibility (CSR) activities, customer demand, and competitive market factors. Policy makers should continue to drive the growth of ICTeLCTs with the introduction and refinement of environmental legislation regulating energy use and markets.     

How predator functional responses and Allee effects in prey affect the paradox of enrichment and population collapses

In Rosenzweig-MacArthur models of predator-prey dynamics, Allee effects in prey usually destabilize interior equilibria and can suppress or enhance limit cycles typical of the paradox of enrichment. We re-evaluate these conclusions through a complete classification of a wide range of Allee effects in prey and predator's functional response shapes. We show that abrupt and deterministic system collapses not preceded by fluctuating predator-prey dynamics occur for sufficiently steep type III functional responses and strong Allee effects (with unstable lower equilibrium in prey dynamics). This phenomenon arises as type III functional responses greatly reduce cyclic dynamics and strong Allee effects promote deterministic collapses. These collapses occur with decreasing predator mortality and/or increasing susceptibility of the prey to fall below the threshold Allee density (e.g. due to increased carrying capacity or the Allee threshold itself). On the other hand, weak Allee effects (without unstable equilibrium in prey dynamics) enlarge the range of carrying capacities for which the cycles occur if predators exhibit decelerating functional responses. We discuss the results in the light of conservation strategies, eradication of alien species, and successful introduction of biocontrol agents.     

Significance of new records of Tridacna squamosa Lamarck, 1819, in the Tuamotu and Gambier Archipelagos (French Polynesia)

The giant clam subfamily Tridacninae (family Cardiidae) is an important group of bivalve molluscs found throughout the Red Sea and Indo-Pacific, from East Africa to the Eastern Pacific biogeographic region. The Tridacna genus is currently revised with numerous cryptic species identified with molecular markers. New Tridacna records from the fringe of the known distribution areas are extremely useful to identify genetically unique species, geographic ranges, and to examine processes associated with species differentiation. While Tridacna maxima is abundant in French Polynesia (Central South Pacific Ocean) the larger fluted giant clam Tridacna squamosa was formerly reported only in the Austral Islands in the south. Following a recent survey that spanned 23 islands and atolls of the Society, Tuamotu and Gambier Archipelagos, the presence of T. squamosa between the Cook Islands and Pitcairn Islands is confirmed using both morphological and molecular information, suggesting a relic distribution across the Central Pacific Ocean. Tridacna squamosa is rare, but present throughout Tuamotu and Gambier. However, it remained undetected from the Society Islands, probably due to historical over-fishing. This species is valued by local inhabitants, and is sought after mainly as gifts and also for a limited local shell trade. The rarity of T. squamosa may call for conservation measures in the near future.     

Evaluating Basking-Habitat Deficiency in the Threatened Eastern Massasauga Rattlesnake

ABSTRACT Woody plant succession is hypothesized to threaten many reptile populations by reducing the amount of solar energy available for thermoregulation. Mitigation via vegetation management is often recommended; however, the need for such management practices rarely has been evaluated. We examined the need for basking-site enhancement for the eastern massasauga rattlesnake (Sistrurus c. catenatus; hereafter EMR) in New York, USA, where only 2 populations remain: one at an open-canopy site and another at a closed-canopy site. Microhabitat temperatures were substantially lower at the closed-canopy site, where EMRs selected the warmest available basking sites. Eastern massasauga rattlesnakes in the open-canopy population selected basking sites that afforded greater cryptic cover. We recommend experimental reduction of shrub cover to improve EMR basking habitat at the closed-canopy site. More generally, we caution that management efforts to reduce shrub cover for basking EMRs should maintain adequate cryptic cover.     

Effects of legumes on soil physical quality in a maize crop

The effect of intercropped legumes and three N fertilizer rates in a continuous maize (Zea mays L.) cropping system on the physical properties of two soils were investigated for three years. The legumes, being a mixture of alfalfa, clover and hairy vetch, had a significant cumulative effect on some physical properties of both soil. The lowest stability and smallest mean weight diameter of soil aggregates were associated with monoculture maize plots. Aggregate size and stability were not affected by N fertilization at any of the rates of 0, 70, and 140 kg ha^-1 in intercropped plots, except that aggregate stability was actually reduced by N fertilization in one soil, the Ste. Rosalie clay. In maize plots in both soils, stability and size of soil aggregates were significantly increased with increased added N. Intercropped legumes significantly decreased dry bulk density and soil penetration resistance. Added N had no measurable influence on these compaction factors. Soil water properties were not significantly affected by either intercropping or N fertilization. Positive effects noted on soil aggregation and other physical properties in intercropped plots are the result of enhanced root activity, or incorporation of legumes as green manure, or both. Improvement of soil structure in maize plots associated with increasing N application was the result of increased maize-root residues.     

Ground beetle species (Carabidae,Coleoptera) activity and richness in relation to crop type,fertility management and crop protection in a farm management comparison trial

Ground beetle activity and species richness was monitored using pitfall traps in a plot trial system on a farm in northern England where the effects of organic and conventional fertility and crop protection management were separated within different crop types between 2005 and 2008. As well as analyses on species activity the beetles were split into small, medium‐sized and large groups, and into groups of herbivores and specific Collembola feeders. Crop type had significant effects on the activity of the 20 most abundant species and all groups, generally with most in beans and winter barley and least in vegetables and spring barley. Most significant reactions to crop protection and fertility management were in cereals and grass/clover. Activity of small species was highest in conventionally crop‐protected cereals but not in vegetables, with more medium‐sized and herbivorous species in organic plots, but there was little influence of crop protection management on large and Collembola feeding species. However, large species were significantly more active in organically fertilised cereals and grass/clover, but not in vegetables, and there were more Collembola feeders in conventional cereals but not in grass/clover. Small species were more abundant in conventionally fertilised grass/clover but there were more in organic cereals and vegetables. These inconsistent activity reactions to management were also observed with individual species but most preferred organically managed plots. There were few significant crop protection : fertility management interactions. Species richness was also significantly affected by crop type and where management had an influence, more species were found in organically managed plots. Constrained ordination emphasised that ground beetle activity was influenced more by crops than by management. Given the diverse nature of organic crop rotations, crop type should be considered a major influence in any environmental manipulation aimed at increasing ground beetle activity for provision of ecosystem services.     

Nitrogen fertilizer and landscape position impacts on CO2 and CH4 fluxes from a landscape seeded to switchgrass

This study was conducted to evaluate the impacts of N fertilizer and landscape position on carbon dioxide (CO₂) and methane (CH₄) fluxes from a US Northern Great Plains landscape seeded to switchgrass (Panicum virgatum L.). The experimental design included three N levels (low, 0 kg N ha⁻¹; medium, 56 kg N ha⁻¹; and high, 112 kg N ha⁻¹) replicated four times. The experiment was repeated at shoulder and footslope positions. Soil CO₂ and CH₄ fluxes were monitored once every 2 weeks from May 2010 to October 2012. The CO₂ fluxes were 40% higher at the footslope than the shoulder landscape position, and CH₄ fluxes were similar in both landscape positions. Soil CO₂ and CH₄ fluxes averaged over the sampling dates were not impacted by N rates. Seasonal variations showed highest CO₂ release and CH₄ uptake in summer and fall, likely due to warmer and moist soil conditions. Higher CH₄ release was observed in winter possibly due to increased anaerobic conditions. However, year to year (2010–2012) variations in soil CO₂ and CH₄ fluxes were more pronounced than the variations due to the impact of landscape positions and N rates. Drought conditions reported in 2012, with higher annual temperature and lower soil moisture than long-term average, resulted in higher summer and fall CO₂ fluxes (between 1.3 and 3 times) than in 2011 and 2010. These conditions also promoted a net CH₄ uptake in 2012 in comparison to 2010 when there was net CH₄ release. Results from this study conclude that landscape positions, air temperature, and soil moisture content strongly influenced soil CO₂ fluxes, whereas soil moisture impacted the direction of CH₄ fluxes (uptake or release). However, a comprehensive life cycle analysis would be appropriate to evaluate environmental impacts associated with switchgrass production under local environmental conditions.     

Effect of Bacillus thuringiensis on Habrobracon hebetor during combined biological control of Plodia interpunctella

Abstract  The suitability of combining microbial pesticides and an insect parasitoid for pest management of stored cereal in China was evaluated using laboratory assays. For this purpose, interactions between Bacillus thuringiensis ( Bt ), Bt -intoxicated host larvae and the parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) were tested against Plodia interpunctella Hübner (Lepidoptera: Pyralidae) . Bt or H. hebetor alone caused 41.67% and 35.35% P. interpunctella larval mortality respectively. The Bt –parasitoid combined treatment significantly increased mortality of P. interpunctella (86%). Progeny development of H. hebetor was dependent upon its susceptibility to Bt . Fewer parasitoids emerged from Bt –parasitoid combined treatment than in non- Bt treatments. However, since Bt did not prevent parasitoid development, a combined treatment with Bt and parasitoid release could produce better protection against P. interpunctella than either treatments when used singly, because their lethal effects were additive to each other.     

An Examination of Scale-Dependent Resource Use by Eastern Hognose Snakes in Southcentral New Hampshire

ABSTRACT The decline of many snake populations is attributable to habitat loss, and knowledge of habitat use is critical to their conservation. Resource characteristics (e.g., relative availability of different habitat types, soils, and slopes) within a landscape are scale-dependent and may not be equal across multiple spatial scales. Thus, it is important to identify the relevant spatial scales at which resource selection occurs. We conducted a radiotelemetry study of eastern hognose snake (Heterodon platirhinos) home range size and resource use at different hierarchical spatial scales. We present the results for 8 snakes radiotracked during a 2-year study at New Boston Air Force Station (NBAFS) in southern New Hampshire, USA, where the species is listed by the state as endangered. Mean home range size (minimum convex polygon) at NBAFS (51.7 ± 14.7 ha) was similar to that reported in other parts of the species’ range. Radiotracked snakes exhibited different patterns of resource use at different spatial scales. At the landscape scale (selection of locations within the landscape), snakes overutilized old-field and forest edge habitats and underutilized forested habitats and wetlands relative to availability. At this scale, snakes also overutilized areas containing sandy loam soils and areas with lower slope (mean slope = 5.2% at snake locations vs. 6.7% at random locations). We failed to detect some of these patterns of resource use at the home range scale (i.e., within the home range). Our ability to detect resource selection by the snakes only at the landscape scale is likely the result of greater heterogeneity in macrohabitat features at the broader landscape scale. From a management perspective, future studies of habitat selection for rare species should include measurement of available habitat at spatial scales larger than the home range. We suggest that the maintenance of open early successional habitats as a component of forested landscapes will be critical for the persistence of eastern hognose snake populations in the northeastern United States.