| 1. |
- Probst, Anne, et al.
(författare)
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Evaluation of Plant Responses to Atmospheric Nitrogen Deposition in France Using Integrated Soil-Vegetation Models
- 2015
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Ingår i: Critical Loads and Dynamic Risk Assessments : Nitrogen, Acidity and Metals in Terrestrial and Aquatic Ecosystems - Nitrogen, Acidity and Metals in Terrestrial and Aquatic Ecosystems. - Dordrecht : Springer Netherlands. - 1566-0745. - 9789401795074 - 9789401795081 ; 25, s. 359-379
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Bokkapitel (refereegranskat)abstract
- The aim of this chapter is to give an overview of plant responses to nitrogen (N) deposition by using two dynamic biogeochemical models coupled with a vegetation module: VSD+-VEG and ForSAFE-VEG. The biogeochemical models were first validated on some French forest sites from the ICP-Forests network. A French vegetation table (which is now part of a European database) containing 230 species with their appropriate ecological environmental parameters, was set up. The outputs of each model in terms of plant response to atmospheric nitrogen deposition were compared to measured values for one forest stand. The two models underestimated the occurrence of certain herbs and grasses and overestimated (ForSAFE-VEG) or underestimated (VSD+-VEG) the presence of certain mosses. This allowed us to improve the validation and thus the calibration of some parameters. For the simulated period ForSAFE-VEG indicated some variations in the occurrence of the plant groups, the mosses group showing the highest increase and indicating a high sensitivity to atmospheric N deposition. No significant changes in the occurrence percentage of plant groups were observed by running the VSD+-VEG model, this model being less sensitive than ForSAFE-VEG to simulate tenuous vegetation changes. The observed changes over time in the dominant ground plant groups using ForSAFE-VEG could be related to changes in site environmental conditions, but only the influence of the maximum N deposition was obvious. Further investigations are needed to compare the performance of the two models on other sites, but these tests of the ForSAFE-VEG and VSD+-VEG models showed promise for simulating the link between N deposition and vegetation diversity.
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| 2. |
- Rizzetto, Simon, et al.
(författare)
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Modelling the impact of climate change and atmospheric N deposition on French forests biodiversity.
- 2016
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491.
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Tidskriftsartikel (refereegranskat)abstract
- A dynamic coupled biogeochemical-ecological model was used to simulate the effects of nitrogen deposition and climate change on plant communities at three forest sites in France. The three sites had different forest covers (sessile oak, Norway spruce and silver fir), three nitrogen loads ranging from relatively low to high, different climatic regions and different soil types. Both the availability of vegetation time series and the environmental niches of the understory species allowed to evaluate the model for predicting the composition of the three plant communities. The calibration of the environmental niches was successful, with a model performance consistently reasonably high throughout the three sites. The model simulations of two climatic and two deposition scenarios showed that climate change may entirely compromise the eventual recovery from eutrophication of the simulated plant communities in response to the reductions in nitrogen deposition. The interplay between climate and deposition was strongly governed by site characteristics and histories in the long term, while forest management remained the main driver of change in the short term.
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| 3. |
- Wasof, Safaa, et al.
(författare)
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Disjunct populations of European vascular plant species keep the same climatic niches
- 2015
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 24:12, s. 1401-1412
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Tidskriftsartikel (refereegranskat)abstract
- 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 degree of niche conservatism between distant populations of native alpine plant species that have been separated for thousands of years. Location European Alps and Fennoscandia. Methods Of the studied pool of 888 terrestrial vascular plant species occurring in both the Alps and Fennoscandia, we used two complementary approaches to test and quantify climatic-niche shifts for 31 species having strictly disjunct populations and 358 species having either a contiguous or a patchy distribution with distant populations. First, we used species distribution modelling to test for a region effect on each species' climatic niche. Second, we quantified niche overlap and shifts in niche width (i.e. ecological amplitude) and position (i.e. ecological optimum) within a bi-dimensional climatic space. Results Only one species (3%) of the 31 species with strictly disjunct populations and 58 species (16%) of the 358 species with distant populations showed a region effect on their climatic niche. Niche overlap was higher for species with strictly disjunct populations than for species with distant populations and highest for arctic-alpine species. Climatic niches were, on average, wider and located towards warmer and wetter conditions in the Alps. Main conclusion Climatic niches seem to be generally conserved between populations that are separated between the Alps and Fennoscandia and have probably been so for 10,000-15,000 years. Therefore, the basic assumption of species distribution models that a species' climatic niche is constant in space and time-at least on time scales 104 years or less-seems to be largely valid for arctic-alpine plants.
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