GIS habitat analysis for lesser prairie-chickens in southeastern New Mexico

Background  

We conducted Geographic Information System (GIS) habitat analyses for lesser prairie-chicken (LPCH, Tympanuchus pallidicinctus) conservation planning. The 876,799 ha study area included most of the occupied habitat for the LPCH in New Mexico. The objectives were to identify and quantify: 1. suitable LPCH habitat in New Mexico, 2. conversion of native habitats, 3. potential for habitat restoration, and 4. unsuitable habitat available for oil and gas activities.     

Effects of shoot,root and stolon temperature on the development of the potato (Solanum tuberosum L.) plant. I. Development of the haulm

Summary Cultivars Bintje and Désirée were grown in a set-up that allowed temperatures of the shoot, root, and stolon environments to be separately varied. Shoot and root temperatures were either low, 18°C, or high, 28°C. Stolon temperatures were either ‘normal’, i.e. allowed to equilibrate at an ambient that depended on the temperatures of the shoot and root compartments, or ‘in-creased’ by fixed supplementary heating units in the stolon chambers. Haulm longevity was increased by the combination high shoot temperature and low root temperature, but greatly decreased by high shoot temperature combined with high root temperature. The increased stolon temperature also advanced senescence. The number of branches per stem (and thereby the number of leaves) was increased by an increase in stolon temperature, but the interaction with air temperature was significant. A high root temperature reduced the number of leaves significantly. The effects on stem yield were complex; several interactions proved significant. The total drymatter yield was affected by all single factors except shoot temperature.     

Stolon characteristics and tuber initiation in a wild potato species (Solanum demissum Lindl.)

Summary Solanum demissum Lindl. is a short-day dependent, tuber-bearing species. In vitro propagated genetically identical plants were grown under long-day (16 h) conditions at 20°C day and 15°C night temperatures. Subsequently, from day 0 onwards, plants were exposed to shortday (10 h) conditions and grown in a multi-compartment system that allowed stolon initiation, stolon branching, stolon growth and tuber initiation to be monitored twice weekly. These frequent measurements resulted in detailed life-histories of all 841 stolon tips formed until day 46. Tuber initiation was irregular under these well-defined conditions; at day 46 only 106 stolon tips showed subapical swelling. This irregularity of tuber initiation was also observed within stolons. It is therefore suggested that tuber initiation depends on characteristics of the stolon or stolon branch, and several such characteristics were analyzed to obtain information on their potentially determining role in tuber initiation. No positive correlations were found between subapical swelling and branching order, stolon and stolon-branch age, longitudinal growth rates of stolons and stolon branches, and attachment of the stolon to the main stem.     

Translating and applying a simulation model to enhance understanding of grassland management

Each new generation of grassland managers could benefit from an improved understanding of how modification of nitrogen application and harvest dates in response to different weather and soil conditions will affect grass yields and quality. The purpose of this study was to develop a freely available grass yield simulation model, validated for England and Wales, and to examine its strengths and weaknesses as a teaching tool for improving grass management. The model, called LINGRA-N-Plus, was implemented in a Microsoft Excel spreadsheet and iteratively evaluated by students and practitioners (farmers, consultants, and researchers) in a series of workshops across the UK over 2 years. The iterative feedback led to the addition of new algorithms, an improved user interface, and the development of a teaching guide. The students and practitioners identified the ease of use and the capacity to understand, visualize and evaluate how decisions, such as variation of cutting intervals, affect grass yields as strengths of the model. We propose that an effective teaching tool must achieve an appropriate balance between being sufficiently detailed to demonstrate the major relationships (e.g., the effect of nitrogen on grass yields) whilst not becoming so complex that the relationships become incomprehensible. We observed that improving the user-interface allowed us to extend the scope of the model without reducing the level of comprehension. The students appeared to be interested in the explanatory nature of the model whilst the practitioners were more interested in the application of a validated model to enhance their decision making.     

Lower soil nitrous oxide emissions by a high lipid genetically modified perennial ryegrass line compared to its wild type

We describe an experiment where cattle urine was applied at a rate of 420 kg N ha⁻¹, equivalent to 10 L m⁻², to mesocosm swards of a high lipid genetically modified perennial ryegrass line (HME) and its wild type (WT). We measured N pools and fluxes in the plant and soil, soil microbial populations and N₂O production. HME plants produced 21% greater biomass than WT (p = .02), resulting in greater N uptake (27% higher in HME, p = .05). Urine N recovery in total plant biomass during the experiment in HME and WT swards were 54.7% and 33.9% respectively. The nitrification potential of soil was significantly lower (p = .01) in HME than WT. Partial least square-discriminant analysis using microbial gene abundance data indicated that HME and WT plant growth induced distinct microbial populations in the soil. These differences in plant soil microbial interactions between HME and WT swards resulted in significantly lower N₂O emissions from the HME sward. Total N₂O emissions over the 4 weeks after urine application was 38% lower (p < .03) in HME swards than in WT swards. The next step in this work is to identify the specific changes in HME traits that drive the reduction in N₂O.     

Growth and Survival of Blackslip Pearl Oyster Larvae Fed Different Densities of Microalgae

This paper reports on an experiment to determine growth and survival of blacklip pearl oyster, Pinctada margaritifera (L.), larvae fed a 1:1 mixture of Isochrysis aff. galbana clone T-ISO and Pavlova salina at six different densities (1, 2, 5, 10, 20 and 30 × 10³ cells ml^-1. Larval growth and survival were assessed every four days over a 20–day period. Exponential and logistic regression models were fitted to the growth and survival responses, respectively. Overall growth of larvae fed 5 × 10³ cells ml^-1 was significantly greater (p > 0.01) than growth of larvae reared at other algal densities. The optimal food ration for maximum larval growth was 20 × 10³ cells ml^-1, which resulted in larvae with antero-posterior shell length of 230 m after 20 days. These larvae were significantly larger (p > 0.05) than those in all other treatments at the end of the experiment. Survival of larvae fed 0, 1 and 2 × 10³ cells ml^-1 was significantly lower than that of larvae in all other treatments at the end of 15 days (p > 0.01). Maximal survival (8%) over the 20 day period was shown by larvae fed 10 × 10³ cells ml^-1, while lower survival was shown by larvae fed 2 × 10³ cells ml^-1 (2%) and 1 × 10³ cells ml^-1 (0%).     

Remotely sensed spatial dynamics of the Illex argentinus fishery, Southwest Atlantic

Illex argentinus, the Argentine short-finned squid, is an important species within the Patagonian shelf ecosystem, where it supports a major multi-national fishery. The fishing fleet operating in this region is comprised of jigging vessels which attract squid using powerful incandescent lights. These fishing lights are detectable in remotely sensed satellite imagery which makes the fishery unusually amenable to a large-scale analysis of its spatial dynamics. In this paper, long-term inter-annual variability in fleet distribution and extent is examined using imagery from the Defence Meteorological Satellite Program-Operational Linescan System (DMSP-OLS) for the period 1993–2005. The fishery was found to occupy a wide area across the shelf and slope, with regions of consistent fishing activity observed on the high seas (45–47°S) and to the north of the Falkland Islands (Malvinas). Distribution of the fishery over the 13-year study period was variable, with 28% of the fished area occupied in 1–2 years, and 7% of the area occupied in 12–13 years. Annual catch levels were positively associated with the extent of the area occupied by the fleet. Higher catches corresponded to the fishery occupying a wide latitudinal range, whereas lower catches were observed during 2004 and 2005 corresponding to a contraction of the fishery away from the south of its range. In years of very high catches, fishing took place along almost the entire latitudinal range of the species. Due to the intensity of fishing, changes in the distribution of the fleet can reflect shifts in the distribution of I. argentinus; this has potential for the long-term monitoring of this highly variable squid fishery.     

Protective Effect of Emodin against Hyperthermia‐induced Stress in Hepatic Cells of Grass Carp,Ctenopharyngodon idellus

Emodin is an anthraquinone exhibiting several positive benefits of anti‐inflammatory, free radical scavenging, and resistance to stress. The goal of this study is to investigate the effects of emodin on the hepatic cell line of grass carp exposed to hyperthermic stress. Cultured cells were treated with various emodin concentrations (0, 0.04, 0.2, and 1.0 µg/mL) at 27 C for 24 h. Then all cultured cells were exposed to thermal stress by increasing the culture temperature (32 ± 0.5 C) for 0.5 h. Increased temperatures significantly reduced cell viability and increased lactate dehydrogenase (LDH) release in three of the four experimental groups (0, 0.2, and 1 µg/mL emodin) compared with the control. Additionally, reactive oxygen species (ROS) were significantly higher in cells exposed to elevated temperatures and treated with 0.2 or 1 µg/mL emodin and mitochondrial membrane potential was significantly lower in cells treated with 0, 0.2, or 1 µg/mL emodin. Expressions of heat shock proteins (HSP60, HSP70, and HSP90) were significantly higher in all but one of the experimental groups. Our results suggest that 0.04 µg/mL emodin can increase cell viability and HSP90 mRNA level, reduce LDH release and concentration of ROS, and contribute to enhance the resistance to high temperature stress in the hepatic cells of grass carp.     

Multiple otolith techniques aid stock discrimination of a broadly distributed deepwater fishery species, blue grenadier, Macruronus novaezelandiae

This study investigated otolith shape, elemental chemistry of otolith cores (first 1-3 months of life), and stable isotope ratios (δ¹⁸O and δ¹³C) of whole otoliths as indicators of stock structure among three important southern Australian blue grenadier Macruronus novaezelandiae fishery regions; west Tasmania - WTAS, east Bass Strait - EBS, and Great Australian Bight - GAB. Comparisons were confined to two dominant cohorts of age 4+ and 13+ years, spawned in winter 2002 and 1993 respectively. Otolith shape varied significantly between the WTAS and GAB regions for the age 4+ cohort only. Cu:Ca of otolith cores was significantly higher for both cohorts from WTAS than EBS and GAB, and Ba:Ca of otolith cores higher for WTAS and EBS than the GAB region. Stable isotopic signatures showed greater variation among regions for the age 13+ cohort. In particular, otoliths of age 13+ fish from WTAS displayed significantly higher δ¹⁸O (indicative of lower temperature history) than age 4+ fish from all regions, and the same age fish from the GAB and EBS regions. δ¹⁸O of blue grenadier otoliths accurately predicted water temperature at their main capture depths of 400-600 m. Chemistry of otolith cores combined with whole otolith isotope ratios discriminated GAB and EBS samples from those collected on the known WTAS spawning ground with moderate to high (64-86%) accuracy. The results provide support for the hypotheses that the GAB fishery is based on a separate stock for management purposes, and that the EBS fishery is likely replenished both from local spawning and the major WTAS spawning region.