A landscape classification map of Ireland and its potential use in national land use monitoring.

This study presents a novel landscape classification map of the Republic of Ireland and is the first to identify broad landscape classes by incorporating physiographic and land cover data. The landscape classification responds to commitments to identify and classify the Irish landscape as a signatory to the European Landscape Convention. The methodology applied a series of clustering iterations to determine an objective multivariate classification of physiographic landscape units and land cover datasets. The classification results determined nine statistically significant landscape classes and the development of a landscape classification map at a national scale. A statistical breakdown of land cover area and diversity of each class was interpreted, and a comparison was extended using independent descriptive variables including farmland use intensity, elevation, and dominant soil type. Each class depicts unique spatial and composition characteristics, from coastal, lowland and elevated, to distinct and dominating land cover types, further explained by the descriptive variables. The significance of individual classes and success of the classification is discussed with particular reference to the wider applicability of the map. The transferability of the methodology to other existing physiographic maps and environmental datasets to generate new landscape classifications is also considered. This novel work facilitates the development of a strategic framework to efficiently monitor, compare and analyse ecological and other land use data that is spatially representative of the distribution and extent of land cover in the Irish countryside.

General stabilizing effects of plant diversity on grassland productivity through population asynchrony and overyielding.

Insurance effects of biodiversity can stabilize the functioning of multispecies ecosystems against environmental variability when differential species' responses lead to asynchronous population dynamics. When responses are not perfectly positively correlated, declines in some populations are compensated by increases in others, smoothing variability in ecosystem productivity. This variance reduction effect of biodiversity is analogous to the risk-spreading benefits of diverse investment portfolios in financial markets. We use data from the BIODEPTH network of grassland biodiversity experiments to perform a general test for stabilizing effects of plant diversity on the temporal variability of individual species, functional groups, and aggregate communities. We tested three potential mechanisms: reduction of temporal variability through population asynchrony; enhancement of long-term average performance through positive selection effects; and increases in the temporal mean due to overyielding. Our results support a stabilizing effect of diversity on the temporal variability of grassland aboveground annual net primary production through two mechanisms. Two-species communities with greater population asynchrony were more stable in their average production over time due to compensatory fluctuations. Overyielding also stabilized productivity by increasing levels of average biomass production relative to temporal variability. However, there was no evidence for a performance-enhancing effect on the temporal mean through positive selection effects. In combination with previous work, our results suggest that stabilizing effects of diversity on community productivity through population asynchrony and overyielding appear to be general in grassland ecosystems.

Diversity-interaction modeling: estimating contributions of species identities and interactions to ecosystem function.

We develop a modeling framework that estimates the effects of species identity and diversity on ecosystem function and permits prediction of the diversity-function relationship across different types of community composition. Rather than just measure an overall effect of diversity, we separately estimate the contributions of different species interactions. This is especially important when both positive and negative interactions occur or where there are patterns in the interactions. Based on different biological assumptions, we can test for different patterns of interaction that correspond to the roles of evenness, functional groups, and functional redundancy. These more parsimonious descriptions can be especially useful in identifying general diversity-function relationships in communities with large numbers of species. We provide an example of the application of the modeling framework. These models describe community-level performance and thus do not require separate measurement of the performance of individual species. This flexible modeling approach can be tailored to test many hypotheses in biodiversity research and can suggest the interaction mechanisms that may be acting.

Plant diversity and productivity experiments in european grasslands

At eight European field sites, the impact of loss of plant diversity on primary productivity was simulated by synthesizing grassland communities with different numbers of plant species. Results differed in detail at each location, but there was an overall log-linear reduction of average aboveground biomass with loss of species. For a given number of species, communities with fewer functional groups were less productive. These diversity effects occurred along with differences associated with species composition and geographic location. Niche complementarity and positive species interactions appear to play a role in generating diversity-productivity relationships within sites in addition to sampling from the species pool.

Competitive Excellence: It's a Matter of Mind and Body.

In brief: Human thought is a complex, sophisticated, amazing, and ongoing process. It cannot be ignored when considering success in sports competition. Until recently, however, mental training has not received as much attention as physical training. This article discusses how athletes may achieve optimal emotional arousal levels in accordance with their specific sports and individual personalities. Self-talk, muscle relaxation, and deep breathing are among the techniques they can use. With practice, athletes can learn to assess and control their emotional arousal level, just as they can improve physical skill with practice. Both result in higher levels of performance.

Acetylcholinesterase mutants in Drosophila and their effects on the structure and function of the central nervous system.

Mutations that eliminate acetylcholinesterase (AChE) activity were used to study the effects of disrupted acetylcholine metabolism on the form and function of the central nervous system in Drosophila melanogaster. Mutants in the Ace gene, which have no AChE activity, usually die in early development, but the postembryonic effects of this lesion can be studied in genetic mosaics, or with conditional mutants. Adult mosaics, which expressed Ace mutations in part of their CNS, exhibited morphological defects in any ganglionic neuropile whose cells were mutant. The defects included reduction in ganglionic volume, a condensed appearance, and for a very large clone, degeneration. Examination of many such mosaics indicated that small clones restricted to one side of the CNS were not usually lethal. However, mosaics with large clones, with clones on either side of the posterior slope of the protocerebrum, or with clones encompassing symmetrical structures on both sides of the CNS rarely survived to adulthood. Mosaics with AChE-null tissue on either side of the optic lobes or the posterior-inferior protocerebrum had marked deficits in optomotor behavior, although they were outwardly normal in their movement and posture. Mosaics with Ace mutant tissue in the first-order optic lobe, the lamina, lacked a synaptic component of the electroretinogram, the "off" transient. Tests of courtship behavior revealed that AChE mosaics with mutant clones in the superior protocerebrum were often capable of demonstrating male courtship. However, their behavior was quantitatively and perhaps qualitatively deficient. In order to study critical periods for the effects of mutant AChE, temperature-sensitive mutations of the Ace gene were isolated. Flies bearing certain of these new mutations produced AchE activity that was thermolabile in vivo and in vitro. The critical period during which the mutants were most susceptible to conditional lethality was late in embryogenesis.