Sökresultat

Little is known about the relative importance of mechanistic drivers of plant spread, particularly when long-distance dispersal (LDD) events occur. Most methods to date approach LDD phenomenologically, and all mechanistic models, with one exception, have been implemented through simulation. Furthermore, the few recent mechanistically derived spread models have examined the relative role of differe

Understanding the relationships between biodiversity and land-use is a key element for the development of effective conservation strategies. We studied a mid-altitude steppe-like area of Southern France, the Causse de Sauveterre, that has been grazed for many centuries. The decrease of human population during the 20th century, particularly since the end of 2nd World War, and the ongoing changes in

Context: The details of fecundity, such as its distribution and timing, can have important consequences for forest dynamics. Aims: We detail two aspects of the reproductive ecology of an exotic population of Pinus nigra in New Zealand. We compare our findings with those reported for P. nigra in southern France and Britain. Methods: We describe variation in fecundity, both within the population and

Recently Prévot-Julliard and colleagues presented a concept paper on biological conservation strategies using exotic species as a case study. They emphasized the difficulty of integrating conservation into a broad picture that accounts for public perception as well as scientific knowledge. We support this general call for better integration of society in conservation research, but we believe that

In Europe, land use changes follow public policies, and particularly the Common Agricultural Policy. To predict the effect of policies on agricultural practices, landscape, and ultimately biodiversity, requires understanding of the interactions between social, economic and ecological dynamics at regional scale. We studied by means of prospective scenarios the possible effects of agricultural chang

The effects of habitat fragmentation on birds have often been studied in forest specialist species. Here we aimed at comparing the response of open habitat birds within a range of habitat specialization. The study area was a Mediterranean pseudo-steppe, designated as important for conservation yet fragmented by tree encroachment. We defined bird species dependency on steppe-like habitat by a corre

Succession theory focuses on the position of species along the shade tolerance gradient and their ability to colonize recently disturbed patches and has for decades overlooked resprouting as a key trait in community patterns. We study how different species traits interact with disturbance frequency to change species dominance in the canopy, focusing on the effects of resprouting ability. We develo

The timing of introduction of a new species into an ecosystem can be critical in determining the invasibility (i.e. the sensitivity to invasion) of a resident population. Here, we use an individual-based model to test how (1) the type of competition (symmetric versus asymmetric) and (2) seed masting influence the success of invasion by producing oscillatory dynamics in resident tree populations. W

Individual-based modelling is a promising tool for scaling from the individual to the population and community levels that allows a wide range of applied and theoretical approaches. Here, we explore how intra-specific competition affects population dynamics using FORSITE, an individual-based model describing tree-tree interactions in a spatial and stochastic context. We first describe FORSITE desi

Potentially significant shifts in the geographical patterns of vegetation are an expected result of climate change. However, the importance of local processes (e.g., dispersal, competition, or disturbance) has been often ignored in climate change modeling. We develop an individual-based simulation approach to assess how these mechanisms affect migration rate. We simulate the northward progression

Biodiversity conservation requires an understanding of the extent to which a landscape can contribute to species life-cycle. Conceived as a dynamic mosaic of spatial units with different properties, landscape is a very relevant scale for dealing with biodiversity issues. This paper aims at analysing the relationships and overlapping between this geography and landscape ecology as two scientific fi

This paper focuses on understanding human impact on landscape. Both ecological and human practices are analysed as interacting processes. An agent-based model integrating biological and historical knowledge is used to analyse the pattern of Scots Pine encroachment in a French Mediterranean upland. In the STIPA model, pine trees are autonomous agents and a cellular automaton simulates land-use. We

Massive multiple-input multiple-output (MIMO) systems, where the base station (BS) is equipped with a large number of antennas and the mobile devices have a single antenna, can significantly enhance the system performance. In many wireless systems inter symbol interference (ISI) due to delay dispersion of the channel can dramatically affect the demodulation process of the received signals. Precodi

Vibrations in a built environment can exceed the requirements for sensitive equipment in a building or can cause annoyance to residents. Hence, there is often a need for reducing such vibrations. The vibrations can originate from ambient sources such as motorway traffic, or from internal sources such as people walking inside the building. Disturbing vibrations can be reduced by reduction measures.

In 'Rollercoaster loop shapes', (Pendrill 2005 Phys. Educ. 40 517) the author started from the observation that although textbook loops are often circular, real rollercoaster loops are not. In this paper the mathematical description of various possible loop shapes, as well as their riding properties was discussed and also how a study of loop shapes can be used in physics education.

The evolution of legal philosophy in Sweden in the first half of the 20th century basically coincides with the history of the so-called Uppsala School, which will be treated extensively in Tome 2 of this volume, in the part devoted to legal realism. Here I will be dealing with Swedish legal philosophy after that period, from the early 1940s onward, when the hitherto dominant influence of the philo

More often than not, it is asserted that Anders Vilhelm Lundstedt (1882-1955), a disciple and friend of Axel Hägerström who enthusiastically embraced the latter’s philosophical theories, (i) went to great lengths to apply those theories in the central fields of law but (ii) actually deviated from Hägerström’s teachings by introducing the complex notion of "social welfare" (or "social utility") as