Terrestrial Movements and Habitat Use of Gopher Frogs (Rana capito) at Fort Benning, Georgia

Gopher frogs (Rana capito) were radio-tracked between the 2000 and 2001 breeding seasons to study their terrestrial movements and habitat use in a longleaf pine- sandhill area on the Fort Benning Military Reservation, Georgia. The telemetry research was conducted in response to the need for biological data concerning gopher frog terrestrial habits. Ultimately the data could aid biologists and land managers in describing critical habitat and the development of a management or recovery plan. Twelve gopher frogs were caught at a herpetofaunal array surrounding two neighboring breeding ponds during a post breeding migration, implanted with miniature transmitters, released and radio-tracked one day per week. Data collected included: distances individuals moved between various locations, types of burrows used as refugia, general habitat descriptions, and extent of habitat use. Results indicated that dispersal distances from the breeding site and distances moved between burrow locations varied a great deal between individuals, however all individuals but one stayed within 300m of the herp array surrounding the breeding site. Burrows used by gopher frogs were either excavated by small mammal such as southeastern pocket gophers (Geomys pinetis) or old field mice {Peromyscus polionotus) or gopher tortoises (Gopherus polyphemus). Gopher tortoise burrows used were almost exclusively inactive or abandoned. All small mammal burrows used appeared to be inactive or abandoned. Habitat types were delineated around the breeding site based on vegetation classifications and timber stand measurements. The total time spent by gopher frogs in delineated habitat types varied from to 116 weekly observations. A positive linear relationship was determined between number of gopher frogs known to use each habitat type, total number of burrows used in each habitat type and percent time gopher frogs spent in each habitat type. Gopher tortoise burrow density was negatively correlated with pine basal area and pine stem diameter, and positively correlated with hardwood basal area. Small mammal burrow density was negatively correlated with pine and hardwood basal area. The total number of observations at gopher tortoise burrows was positively correlated with hardwood stem diameter

Disability and self-directed employment : business development models

Co-published by IDRC and Captus University Publication

Adaptation to Climate Change: Why is it Needed and How Can it be Implemented?

This is the 3rd study to be published in the CEPS Policy Brief series from ongoing research being carried out for the EU-funded ADAM project (ADaptation And Mitigation strategies: supporting European climate policy). Following an introduction to the aims and objectives of the ADAM project, section 2 sets out the rationales for public policy related to adaptation to the impacts of climatic change in the EU. Section 3 provides evidence from a number of stakeholders and sketches the perception of various actors towards the role of European adaptation policies and climate proofing of sectoral policies. Section 4 on the economics of adaptation argues that the economic impacts of climate change will mainly be reduced by private and autonomous response, while principal challenges are with adaptation needs that require collective action and public engagement, including public finance. Section 5 assesses monetary and socioeconomic risks from extreme weather events in Europe and points to the evidence of rising losses due to weather extremes whilst important knowledge gaps remain to project future risks. And the final section (6) deals with different concepts of uncertainties surrounding climate change and climate variability, and argues for adaptive measures to be sufficiently flexible to allow recalibration as uncertainties are reduced with time

Evaluating socio-economic and environmental sustainability of the sheep farming activity in Greece: a whole-farm mathematical programming approach

Ruminant livestock farming is an important agricultural activity, mainly located in less favoured areas. Furthermore, ruminants have been identi fi ed as a signi fi cant source of GHG emissions. In this study, a whole-farm optimization model is used to assess the socio-economic and environmental performance of the dairy sheep farming activity in Greece. The analysis is undertaken in two sheep farms that represent the extensive and the semi-intensive farming systems. Gross margin and labour are regarded as socio-economic indicators and GHG emissions as environmental indicators. The issue of the marginal abatement cost is also addressed. The results indicate that the semi-intensive system yields a higher gross margin/ewe (179 €) than the extensive system (117 €) and requires less labour. The extensive system causes higher emissions/kg of milk than the semi-intensive system (5.45 and 2.99 kg of CO2 equivalents, respectively). In both production systems, abatement is achieved primarily via reduction of the fl ock size and switch to cash crops. However, the marginal abatement cost is much higher in the case of the semi-intensive farms, due to their high productivity

Understanding the roles of forests and tree-based systems in food provision

Forests and other tree-based systems such as agroforestry contribute to food and nutritional security in myriad ways. Directly, trees provide a variety of healthy foods including fruits, leafy vegetables, nuts, seeds and edible oils that can diversify diets and address seasonal food and nutritional gaps. Forests are also sources of a wider range of edible plants and fungi, as well as bushmeat, fish and insects. Treebased systems also support the provision of fodder for meat and dairy animals, of “green fertiliser” to support crop production and of woodfuel, crucial in many communities for cooking food. Indirectly, forests and tree-based systems are a source of income to support communities to purchase foods and they also provide environmental services that support crop production. There are, however, complexities in quantifying the relative benefits and costs of tree-based systems in food provision. These complexities mean that the roles of tree-based systems are often not well understood. A greater understanding focuses on systematic methods for characterising effects across different landscapes and on key indicators, such as dietary diversity measures. This chapter provides a number of case studies to highlight the relevance of forests and tree-based systems for food security and nutrition, and indicates where there is a need to further quantify the roles of these systems, allowing proper integration of their contribution into national and international developmental policies

Nitrogen turnover and N2_{2}O/N2_{2} ratio of three contrasting tropical soils amended with biochar

Biochar has been reported to reduce emission of nitrous oxide (N$_{2}$O) from soils, but the mechanisms responsible remain fragmentary. For example, it is unclear how biochar effects on N$_{2}$O emissions are mediated through biochar effects on soil gross N turnover rates. Hence, we conducted an incubation study with three contrasting agricultural soils from Kenya (an Acrisol cultivated for 10-years (Acrisol10); an Acrisol cultivated for over 100-years (Acrisol100); a Ferralsol cultivated for over 100 years (Ferralsol)). The soils were amended with biochar at either 2% or 4% w/w. The $^{15}$N pool dilution technique was used to quantify gross N mineralization and nitrification and microbial consumption of extractable N over a 20-day incubation period at 25 °C and 70% water holding capacity of the soil, accompanied by N$_{2}$O emissions measurements. Direct measurements of N$_{2}$ emissions were conducted using the helium gas flow soil core method. N$_{2}$O emissions varied across soils with higher emissions in Acrisols than in Ferralsols. Addition of 2% biochar reduced N$_{2}$O emissions in all soils by 53 to 78% with no significant further reduction induced by addition at 4%. Biochar effects on soil nitrate concentrations were highly variable across soils, ranging from a reduction, no effect and an increase. Biochar addition stimulated gross N mineralization in Acrisol-10 and Acrisol-100 soils at both addition rates with no effect observed for the Ferralsol. In contrast, gross nitrification was stimulated in only one soil but only at a 4% application rate. Also, biochar effects on increased NH$_{4}$$^{+}$ immobilization and NO$_{3}$$^{-}$−consumption strongly varied across the three investigated soils. The variable and bidirectional biochar effects on gross N turnover in conjunction with the unambiguous and consistent reduction of N$_{2}$O emissions suggested that the inhibiting effect of biochar on soil N$_{2}$O emission seemed to be decoupled from gross microbial N turnover processes. With biochar application, N$_{2}$ emissions were about an order of magnitude higher for Acrisol-10 soils compared to Acrisol-100 and Ferralsol-100 soils. Our N$_{2}$O and N$_{2}$ flux data thus support an explanation of direct promotion of gross N2O reduction by biochar rather than effects on soil extractable N dynamics. Effects of biochar on soil extractable N and gross N turnover, however, might be highly variable across different soils as found here for three typical agricultural soils of Kenya

Agroforestry with N2-fixing trees: sustainable development's friend or foe?

Legume tree-based farming systems sit at a crucial nexus of agroecological sustainability. Their capacity to support microbial N2 fixation can increase soil nitrogen (N) availability and therefore improve soil fertility, crop yields, and support long-term stewardship of natural resources. However, increasing N availability oftentimes catalyzes the release of N into the surrounding environment, in particular nitrous oxide (N2O)—a potent greenhouse gas. We summarize current knowledge on the agroecological footprint of legume-based agroforestry and provide a first appraisal of whether the technology represents a pathway toward sustainable development or an environmental hazard