Design Patterns for Spatio-temporal Processes

Time is an essential dimension to analyse and understand real-world evolution. Although many temporal extensions to spatial models have been proposed, there is still a need to define modelling methods to describe and represent real-world phenomena. This paper presents a set of design patterns modelling spatio-temporal processes expressed in an object-relationship data model. The proposed framework is based on an analysis of spatio-temporal processes and on properties of object-oriented and entity-relationship data models. 1. Introduction Geographical processes involve entities and changes that are located in both space and time. Therefore, building a taxonomy of spatio-temporal processes (STP) implies an analysis of the representation of facts and events within a space-time framework. According to Peuquet (1994), scientists retain two complementary ontological views to define space-time structures. The absolute approach (introduced by Newton) identifies space as a collection of points..

Genetic survey of two endangered grasshopper subspecies, Prionotropis hystrix rhodanica and Prionotropis hystrix azami (Orthoptera, Pamphagidae): within- and between-population dynamics at the regional scale

Corresponding author:[email protected] audienceThe fragmentation and destruction of natural habitats is one of the major causes of extinction of wild flora and fauna due to human activities. The area around the Mediterranean Basin is particularly affected: this region is one of the world’s richest in terms of biodiversity and is undergoing substantial modification due to extensive changes in land use. We investigated the demographic state (through a genetic survey) of an endangered grasshopper, the geographical distribution of which is restricted to arid open land or glades in south-eastern France. We compared two subspecies: one is severely threatened by the fragmentation of its specific and restricted habitat (Prionotropis hystrix rhodanica in the ‘Crau’ steppe) whereas the other, P. h. azami, occurs more widely in glades or clearings in the evergreen Mediterranean forest. Genetic diversity at eight microsatellite loci was highly structured, indicating substantial isolation of populations. Within-population diversity was high at all but one site. Genetic drift was the major force involved in this genetic structure, with very little gene flow at the regional scale of observation, consistent with both the limited dispersal of this flightless species and the patchy configuration of its habitat. No significant differences in the extent of genetic diversity or population dynamics were observed between the two sub-species. The observed genetic pattern calls into question the validity of the subspecies status, and shows no strong impact of recent anthropogenic modification of the Crau steppe. The evolution of the Mediterranean3323 xeric and open habitats under both natural and anthropogenic processes is discusse