Assessing the Geographic Representativeness of Genebank Collections: the Case of Bolivian Wild Potatoes

Abstract: Genebank collection databases can be used for ecogeographical studies under the assumption that the accessions are a geographically unbiased sample. We evaluated the representativeness of a collection of wild potatoes from Bolivia and defined and assessed four types of bias: species, species-area, hotspot, and infrastructure. Species bias is the sampling of some species more often than others. Species-area bias is a sampling that is disproportionate to the total area in which a species is found. Hotspot bias is the disproportionate sampling of areas with high levels of diversity. Infrastructure bias is the disproportionate sampling of areas near roads and towns. Each of these biases is present in the Bolivian wild potato collection. The infrastructure bias was strong: 60% of all wild potato accessions were collected within 2 km of a road, as opposed to 22%, if collections had been made randomly. This analysis can serve as a guide for future collecting trips. It can also provide baseline information for the application of genebank data in studies based on geographic information systems.     

Chemical composition of the slippery epicuticular wax blooms on Macaranga (Euphorbiaceae) ant-plants

Summary. The stems of many Macaranga ant-plants (Euphorbiaceae) are covered by epicuticular wax crystals rendering the surface very slippery for most insects. These wax blooms act as selective barriers protecting the symbiotic ant partners, which are specialized “wax-runners”, against the competition of other ants. Glaucous stems occur almost exclusively among the ant-plants of the genus Macaranga (). We analyzed the cuticular lipids of 16 Macaranga species by GC-MS and investigated the wax crystal morphology using SEM. Presence of crystalline wax blooms was strongly correlated with high concentrations (52%–88%) of triterpenoids. In contrast epicuticular waxes of glossy Macaranga surfaces contained only 0% to 36% of these dominant components. Therefore we conclude that triterpenoids are responsible for the formation of the thread-like Macaranga wax crystals. In all Macaranga ant-plants investigated, the principal components were epitaraxerol and taraxerone accompanied by smaller portions of taraxerol, β-amyrin and friedelin. Only in the case of the non-myrmecophytic M. tanarius did β-amyrin predominate. Moreover, we found that only in M. tanarius, the dense wax crystal lacework is torn into large mosaic-like pieces in the course of secondary stem diameter growth. Both chemical and macroscopic differences may contribute to a reduced slipperiness of M. tanarius stems and appear to be functionally important. The distribution of wax crystals and their composition amongst different sections of the genus suggests that glaucousness is a polyphyletic character within Macaranga. Received 7 October 1999; accepted 3 December 1999     

Prognosis of the spatiotemporal dynamics of ecosystems by means of universal kriging

The use of quantitative data for constructing prognostic maps of the dynamics of ecosystem degradation and restoration by nonlinear simulation methods is a topical field of landscape ecology. This method of dynamic cartography is based on fiberwise comparison of data on the state of Chernye Zemli (the Kalmyk Republic, Russia) in different years and the detailed analysis of the period on which the prognosis was based. For this purpose, materials of repeated aerial and satellite photography obtained during a long period (1954–1993) were used. Comparison of maps characterizing the dynamics of Chernye Zemli between 1958 and 1993 allows prognostic electronic maps for the next 10–15 years (with a five-year interval) to be drawn and land prognosis for the next 20–30 years (1998–2023) to be obtained. Deceased     

Characteristics of the Predator–Prey Interactions and the Horizontal Distribution of Macrozoobenthos in Small Lakes of Different Types

The horizontal distribution and quantitative characteristics of macrozoobenthos were studied in small lakes of the Darwin Nature Reserve (southern Vologda oblast). The aggregation index varied in the open areas of acid lakes, which indicated that communities of small acid water bodies were unstable. The aggregation was the lowest in the open area of a neutral lake. In acid lakes, the number and biomass of macroinvertebrates were the highest near the coasts. In the neutral lake, conversely, these values were maximum in open areas and low near the coast due to a strong pressure of predatory invertebrates and fish. An aggregating effect of invertebrate predators was observed near the coasts of lakes of different types.     

Modelling the Distribution and Quality of Sand and Gravel Resources in 3D: a Case Study in the Thames Basin,UK

Three-dimensional (3D) models are often utilised to assess the presence of sand and gravel deposits. Expanding these models to provide a better indication of the suitability of the deposit as aggregate for use in construction would be advantageous. This, however, leads to statistical challenges. To be effective, models must be able to reflect the interdependencies between different criteria (e.g. depth to deposit, thickness of deposit, ratio of mineral to waste, proportion of ‘fines’) as well as the inherent uncertainty introduced because models are derived from a limited set of boreholes in a study region. Using legacy borehole data collected during a systematic survey of sand and gravel deposits in the UK, we have developed a 3D model for a 2400 km² region close to Reading, southern England. In developing the model, we have reassessed the borehole grading data to reflect modern extraction criteria and explored the most suitable statistical modelling technique. The additive log-ratio transform and the linear model of coregionalization have been applied, techniques that have been previously used to map soil texture classes in two dimensions, to assess the quality of sand and gravel deposits in the area. The application of these statistical techniques leads to a model which can be used to generate thousands of plausible realisations of the deposit which fully reflect the extent of model uncertainty. The approach offers potential to improve regional-scale mineral planning by providing an enhanced understanding of sand and gravel deposits and the extent to which they meet current extraction criteria.

     

A measurement of community disaster resilience in Korea

Building a community that is resilient to disasters has become one of the main goals of disaster management. Communities that are more disaster resilient often experience less impact from the disaster and reduced recovery periods afterwards. This study develops a methodology for constructing a set of indicators measuring Community Disaster Resilience Index (CDRI) in terms of human, social, economic, environmental, and institutional factors. In this study, the degree of community resilience to natural disasters was measured for 229 local municipalities in Korea, followed by an examination of the relationship between the aggregated CDRI and disaster losses, using an ordinary least squares (OLS) regression method and a geographically weighted regression (GWR) method. Identifying the extent of community resilience to natural disasters would provide emergency managers and decision-makers with strategic directions for improving local communities' resilience to natural disasters while reducing the negative impacts of disasters.