Search results for " modelling."
showing 10 items of 983 documents
Disjunct populations of European vascular plant species keep the same climatic niches
2015
Aim Previous research on how climatic niches vary across species ranges has focused on a limited number of species, mostly invasive, and has not, to date, been very conclusive. Here we assess the d ...
Statistical modelling and RCS detrending methods provide similar estimates of long-term trend in radial growth of common beech in north-eastern France
2011
International audience; Dendrochronological methods have greatly contributed to the documentation of past long-term trends in forest growth. These methods primarily focus on the high-frequency signals of tree ring chronologies. They require the removal of the ageing trend in tree growth, known as 'standardisation' or 'detrending', as a prerequisite to the estimation of such trends. Because the approach is sequential, it may however absorb part of the low-frequency historical signal. In this study, we investigate the effect of a sequential and a simultaneous estimation of the ageing trend on the chronology of growth. We formerly developed a method to estimate historical changes in growth, in…
Environmental Modelling of Forest Vegetation Zones as A Support Tool for Sustainable Management of Central European Spruce Forests
2018
Abstract The impact of climate change on forest ecosystems may manifest itself by a shift in forest vegetation zones in the landscape northward and into higher elevations. Studies of climate change-induced vegetation zone shifts in forest ecosystems have been relatively rare in the context of European temperate zone (apart from Alpine regions). The presented paper outlines the results of a biogeographic model of climatic conditions in forest vegetation zones applied in the Central European landscape. The objective of the study is a prediction of future silvicultural conditions for the Norway spruce (Picea abies L. Karst.), which is one of the principal tree species within European forests. …
IPSIM-Cirsium, a Qualitative Expert-Based Model to Predict Infestations of Cirsium arvense
2021
Throughout Europe, Cirsium arvense is the most problematic perennial weed in arable crops, whether managed under organic or conventional agriculture. Non-chemical control methods are limited with partial efficacy. Knowledge is missing on their effect across a wide gradient of cropping systems and pedoclimates. To achieve effective Cirsium arvense management ensuring crop productivity while limiting the reliance of cropping systems on herbicide, expert-based models are needed to gather knowledge on the effect of individual levers and their interactions in order to (i) design and assess finely tuned combinations of farming practices in different pedoclimates and (ii) support decisions for Cir…
Adapted conservation measures are required to save the Iberian lynx in a changing climate
2013
The Iberian lynx ( Lynx pardinus ) has suffered severe population declines in the twentieth century and is now on the brink of extinction 1 . Climate change could further threaten the survival of the species 2 , but its forecast effects are being neglected in recovery plans 3,4 . Quantitative estimates of extinction risk under climate change have so far mostly relied on inferences from correlative projections of species’ habitat shifts 5 . Here we use ecological niche models coupled to metapopulation simulations with source–sink dynamics 6,7 to directly investi- gate the combined effects of climate change, prey availabil- ity and management intervention on the persistence of the Iberian lyn…
The influence of temperature model assumptions on the prognosis accuracy of extinction risk
2000
Abstract For a species whose abundance is well-known to correlate on the degree of heat different temperature model assumptions may affect the prognosis accuracy of persistence. Likewise, year-to-year autocorrelations in weather fluctuations are known to decrease extinction risk. Thus, we investigated the grey bush cricket Platycleis albopunctata . For this species is known that growth and reproduction is mainly influenced by temperature. We developed a stochastic individual based model for the bush cricket. This day–degree model described the demographic growth of the species that depends on temperature. Daily temperatures were generated by five different methods: (i) temperatures were seq…
Regional and Supra-Regional Coherence in Limnological Variabler
2009
Limnologists and water resources managers have traditionally perceived lakes as discrete geographical entities. This has resulted in a tendency for scientific lake studies to concentrate on lakes as individuals, with little connection either to each other or to large-scale driving forces. Since the 1990s, however, a shift in the prevailing paradigm has occurred, with lakes increasingly being seen as responding to regional, rather than local, driving forces. The seminal work on regional coherence in lake behaviour was that of Magnuson et al. (1990), who showed that many features of lakes within the same region respond coherently to drivers such as climate forcing and catchment processes. Fro…
Common Bottlenose Dolphin Protection and Sustainable Boating: Species Distribution Modeling for Effective Coastal Planning
2020
Indicators for preserving marine biodiversity include knowledge of how the spatial distribution and critical habitats of species overlap with human activities and impacts. Such indicators are key tools for marine spatial planning, a process that identifies and resolves conflicts between human uses and the conservation of marine environments. The common bottlenose dolphin in the Mediterranean Sea is considered a vulnerable species by the IUCN Red List and a priority species of the EU Habitat Directive. Here, we estimated spatio-temporal patterns of the species occurrence in the area around one Marine Protected Area (MPA) and two Sites of Community Importance (SCI) of the North western Sardin…
Identifying the best fishing-suitable areas under the new European discard ban
2016
Abstract The spatial management of fisheries has been repeatedly proposed as a discard mitigation measure. A number of studies have assessed the fishing suitability of an area based on units of by-catch or discard per unit effort. However, correct identification of fishing-suitable areas should assess biomass loss with respect to the benefits. This study therefore, proposes the analysis of by-catch ratios, which do represent benefit vs. loss and are standardized to a wide range of effort characteristics. Furthermore, our study proposes the use of two ratios: the proportion of total unwanted biomass out of the total catch as an indicator of the overall ecological impact, and the proportion o…
Movement of forest-dependent dung beetles through riparian buffers in Bornean oil palm plantations
2022
1. Fragmentation of tropical forests is increasing globally, with negative impacts for biodiversity. In Southeast Asia, expansion of oil palm agriculture has caused widespread deforestation, forest degradation and fragmentation. 2. Persistence of forest-dependent species within these fragmented landscapes is likely to depend on the capacity of individuals to move between forest patches. In oil palm landscapes, riparian buffers along streams and rivers are potential movement corridors, but their use by moving animals is poorly studied. 3. We examined how six dung beetle species traversed riparian buffers connected to a continuous forest reserve area within an oil palm plantation in Sabah, Ma…