Species diversity: Concept,measurement, and response to clearcutting and site-preparation

A review of aspects of diversity recently introduced in the statistical literature by Patil and Tallie is given: species diversity as an average property of a community is defined; the property averaged is identified as species rarity; and relations between common indices of diversity and associated measures of rarity are illuminated. This paper also computes common indices of diversity from substantial empirical data collected before clearcutting and site-preparation under two management regimes and for 3 years following planting of slash pine (Pinus elliottii) to illustrate that the initial response to these forest operations is increased species diversity, i.e., increased species rarity. This response may be expected whenever clearcutting and site preparation reduces but does not eliminate previously abundant, late-successional species and permits the reappearance of early-successional species, including forbs and grasses.     

Survival of chromium-51-labeled autologous and homologous erythrocytes in goats.

Apparent half-survival time of 51-Cr-tagged caprine erythrocytes after autotransfusion was 8 days. The 51Cr-tagged homologous caprine erythrocytes disappeared from circulation very rapidly, thereby indicating that it is not possible to produce sustained polycythemia in goats by hypertransfusing them with homologous erythrocytes without appropriate matching.     

Topical 0.1% tacrolimus for the treatment of discoid lupus erythematosus and pemphigus erythematosus in dogs

Topical 0.1% tacrolimus was used for treatment of localized lesions associated with 10 cases of discoid lupus erythematosus (DLE) and two cases of pemphigus erythematosus (PE) either as a sole therapy (n=2) or as an adjunctive treatment (n=10). Eight of 10 dogs with DLE and both dogs with PE were improved following 8 weeks of topical application. In six of the eight dogs that improved, other medications were discontinued. No adverse effects in clinical or laboratory parameters were noted throughout the study.     

Effect of spatial scale of soil data on estimates of soil ecosystem services: Case study in 100 km2 area in France

Over the last decade, the ecosystem services (ESs) framework has been increasingly used to support mapping and assessment studies for sustainable land management purposes. Previous analysis of practical applications has revealed the significance of the spatial scale at which input data are obtained. This issue is particularly problematic with soil data that are often unavailable or available only at coarse scales or resolutions in various part of the world. In this context, four soil-based ecosystem services, namely biomass provision, water provision, global climate regulation, and water quality regulation, are assessed using three conventional soil maps at the 1:1,000,000, 1:250,000 and 1:50,000 scales. The resulting individual and joint ES maps are then compared to examine the effects of changing the spatial scale of soil data on the ES levels and spatial patterns. ES levels are finally aggregated to landforms, land use, or administrative levels in order to try to identify the determinants of the sensitivity of ES levels to change in the scale of input soil data. Whereas the three soil maps turn out to be equally useful whenever ESs levels averaged over the whole 100 km² territory are needed, the maps at the 1:1,000,000 and 1:250,000 induced biases in the assessment of ESs levels over spatial units smaller than 100 and 10 km², respectively. The simplification of the diversity and spatial distribution of soils at the two coarsest scales indeed resulted in local differences in ES levels ranging from several 10 to several 100%. Identification of the optimal representation of soil diversity and distribution to obtain a reliable representation of ESs spatial distribution is not straightforward. The ESs sensitivity to scale effect is indeed context-specific, variable among individual ESs, and not directly or simply linked with the soil typological diversity represented in soil maps. Forested and natural lands in the study area appear particularly sensitive to soil data scales as they occupy marginal soils showing very specific ESs signatures.     

Effects of edaphic conditions on site quality for Salix purpurea ‘Hotel’ plantations across a large climatic gradient in Canada

Willow has been identified as a possible species for supplying large quantities of biomass for bioenergy and wood fibers in Canada. However, before site selection occurs, there is a need to know how the soils and climate of the prairies and central regions affect willow productivity. Soil, foliar, and climatic variables were therefore measured along with yields at nine “first rotation” Salix purpurea ‘Hotel’ plantations from central Alberta to southern Ontario. Correlation analysis was used to identify those parameters having the most influence on yields. Relationships between soil and climate and growth were established by regression analysis. The acid–base status of the soil as dictated by bulk elemental composition, in particular the presence of Ca, was found to be the dominant factor affecting productivity (r = 0.967, P < 0.001 total Ca vs. yields) despite large regional differences in climate. From a nutritional standpoint, total soil N (r = 0.743, P = 0.048) and foliar K (r = 0.938, P = 0.009 for sites with adequate moisture) were positively correlated with growth. S. purpurea ‘Hotel’ yields were found to be primarily limited by water availability at the two lowest productivity prairie sites. Soil total Ca concentration, pH and total organic C concentration were all generally correlated with higher yields. Additional deficiencies appeared in the following order of importance: water > N and K > Mg. As a whole, soil properties were the dominant predictors of ‘Hotel’ growth in this study, which suggests that, even at the regional scale, growth was governed in large part by the capacity of soils to retain water and/or nutrients. Climate played a lesser role, except perhaps at two sites which appeared to receive inadequate moisture.     

Climate Change and North American Rangelands: Assessment of Mitigation and Adaptation Strategies

Recent climatic trends and climate model projections indicate that climate change will modify rangeland ecosystem functions and the services and livelihoods that they provision. Recent history has demonstrated that climatic variability has a strong influence on both ecological and social components of rangeland systems and that these systems possess substantial capacity to adapt to climatic variability. Specific objectives of this synthesis are to: 1) evaluate options to mitigate greenhouse gas emissions and future climate change; 2) survey actions that individuals, enterprises, and social organizations can use to adapt to climate change; and 3) assess options for system transformation when adaptation is no longer sufficient to contend with climate change. Mitigation for carbon sequestration does not appear economically viable, given the small and highly variable carbon dioxide fluxes of rangeland ecosystems and the high transaction costs that would be incurred. In contrast, adaptation strategies are numerous and provide a means to manage risks associated with climate change. Adaptation strategies are diverse, including altered risk perception by individuals, greater flexibility of production enterprises, and modifications to social organizations that emphasize climatic variability, rather than consistency. Many adaptations represent “no regrets” actions because their implementation can be justified without emphasis on pending climate change. Adaptations specific to livestock production systems can include flexible herd management, alternative livestock breeds or species, innovative pest management, modified enterprise structures, and geographic relocation. Social-ecological systems in which adaptation is insufficient to counter the adverse consequences of climate change might undergo transformative change to produce alternative ecosystem services, production enterprises, and livelihoods. The rangeland profession is in a pivotal position to provide leadership on this global challenge because it represents the intersection of management and scientific knowledge, includes diverse stakeholders who derive their livelihoods from rangelands, and interacts with organizations responsible for rangeland stewardship.