An integrated study of the development of organic rice cultivation in the Camargue (France)-

In the Camargue, rice and durum wheat are associated in rotations that have an ambivalent ecological impact: on the one hand, these two crops contribute to the preservation of the surrounding ecosystem, while on the other hand, when cropped intensively, they can threaten the ecological equilibrium of this protected area. In this context, organic agriculture would seem to be an alternative adopted by a certain number of producers and processors. However, the pioneers of this practice encounter numerous problems, both agronomic and economic. The study presented here aims: to construct a pluridisciplinary approach to analyse the conditions of the development of organic cereal cultivation in the Camargue: to identify the principal factors that limit the development of this new practice: to produce knowledge useful in helping ricegrowers put into practice organic cropping systems

Impact of the insecticide Alphacypermetrine and herbicide Oxadiazon, used singly or in combination, on the most abundant frog in French rice fields, Pelophylax …

International audienceno abstrac

Data from: Competition is a strong driving factor in wetlands, peaking during drying out periods

The aim of the study is to investigate the relative importance of plant-plant interactions with regard to flooding and drought effect on perennial plant performances in wetlands. Flooding is expected to be the major driver and, accordingly, the importance of drought is hardly if ever taken into account. Focusing on five widespread species, the growth, the survival and the competitive ability of plants were monitored on permanent plots spread along two elevation gradients. Flooding duration and drought intensity were found to vary substantially along the ~ 0.5 meter range elevation gradient. Flooding and drought alternate over the hydrological year and the pin-point surveys were thus conducted over the course of one year. The data were modeled taking into account survival, recruitment and competitive growth throughout flooding and drying out periods. Flooding and drought both directly impacted the plant performances and their competitive effect, with the effect of drought being much more general among species and of higher magnitude than flooding. The importance of competition was found to be high for all species, particularly during the drying out period. It varied more along the flooding gradient than along the drought gradient. The higher flooding tolerance shown by the studied species compared to drought may be related to species specific growth timing together with efficient response traits. These results offer new insights into the filters operating over the species pools. This suggests that the drying out period and drought conditions may be even more important for species’ relative success and the importance of competition than the flooding pattern. The general applicability of this result, obtained in mild Atlantic climate and fertile wetlands, remains to be studied

Data from: Competition is a strong driving factor in wetlands, peaking during drying out periods

The aim of the study is to investigate the relative importance of plant-plant interactions with regard to flooding and drought effect on perennial plant performances in wetlands. Flooding is expected to be the major driver and, accordingly, the importance of drought is hardly if ever taken into account. Focusing on five widespread species, the growth, the survival and the competitive ability of plants were monitored on permanent plots spread along two elevation gradients. Flooding duration and drought intensity were found to vary substantially along the ~ 0.5 meter range elevation gradient. Flooding and drought alternate over the hydrological year and the pin-point surveys were thus conducted over the course of one year. The data were modeled taking into account survival, recruitment and competitive growth throughout flooding and drying out periods. Flooding and drought both directly impacted the plant performances and their competitive effect, with the effect of drought being much more general among species and of higher magnitude than flooding. The importance of competition was found to be high for all species, particularly during the drying out period. It varied more along the flooding gradient than along the drought gradient. The higher flooding tolerance shown by the studied species compared to drought may be related to species specific growth timing together with efficient response traits. These results offer new insights into the filters operating over the species pools. This suggests that the drying out period and drought conditions may be even more important for species’ relative success and the importance of competition than the flooding pattern. The general applicability of this result, obtained in mild Atlantic climate and fertile wetlands, remains to be studied

pin points reading along elevation gradients in wetlands

This data corresponds to the reading of plant vegetation surveys conducted on plots 25x25 cm large, with 18 readings (R1 to R18) on each plot. Each count is the number of hits per species. They were recorded on 70 plots, 25 x 25cm large, placed every 20 cm along two elevation transects used as replicates (35 plots per sequence). Plots were proteted from grazing by cattle and horses. On each plot, vegetation relevés were performed along both diagonals using the pinpoint method, with a record every 4 cm. Three readings were made: on the 23-29 October, 2008 (Year 1, period 2), on the 3-12 June, 2009 (Year 2, period 1) and on the 19-20 October, 2009 (Year 2, period 2). Aeration Sum Exceedance values were measured based on water table field monitoring, and foflowing Gowing et al. 1998. Predicting the effect of change in water regime on plant communities. In: Wheater H, Kirby C, editors. Hydrology in a Changing Environment vol. I. John Wiley, Chichester: pp. 473–48

Présentation du réseau E.S.P.A.C.E. Entretien des sites à préserver par des animaux conduits en extensif

National audienc

Greylag geese Anser anser – Scirpus maritimus relationships in a newly colonised wintering area in the Camargue (France)

In order to evaluate the proportion of Scirpus maritimus tubers consumed by a growing population of wintering Greylag goose (Anser anser) in Camargue, Southern France, we (1) measured the biomass of Scirpus maritimus tubers on the main resting and feeding marsh for geese in the area; and (2) evaluated, on the basis of their feeding behaviour, the consumption of Scirpus maritimus tubers by geese and changes in this consumption in relation to environmental factors. Mean tuber density and biomass were estimated at 7078 tubers per m2 and 0.61 g per tuber, respectively. The mean number of tubers taken per goose per day was estimated at 633 tubers. The foraging efficiency of geese was greatest when birds used head-dip (vs. up-ending) feeding in water depths of approx. 30 cm. Consumption by geese during the winter was estimated at 20.71 tons. Annual consumption by geese (> 50,000 goose-days) represented 1.2% of all tubers present in the whole area. On the basis of these results, we suspect that the marsh could potentially support a number of geese considerably larger than currently present in winter. Nevertheless, the preferential use of some parts of the marsh seems to indicate that parameters other than food availability could also determine geese feeding behaviour

Importance of competition calculated for each group of species along the drought gradient, with an initial cover of species, i, j and k: 1, 1, 0.

<p>Competition importance represents the proportion of change in ecological success caused by competition relative to environmental conditions. The SEVd was calculated following [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130152#pone.0130152.ref011" target="_blank">11</a>] and expressed as cm.day-1. The Fig 3 (a, b, c, d) report the results for <i>Agrostis stolonifera</i> modeled in pair with respectively <i>Lolium perenne</i>, <i>Cynosurus cristatus</i>, <i>Juncus gerardi</i>, <i>Glyceria fluitans</i>. Results for <i>Lolium perenne</i> are reported in Fig 3a’, <i>for Cynosurus cristatus</i> in Fig 3b’, for <i>Juncus gerardi</i> in Fig 3c’ and for <i>Glyceria fluitans</i> in Fig 3d’.</p

Median of a₁ estimating specific plant growth and c₁, estimating species competitive effect, along flooding (A, C) and drought gradients (B, D).

<p>A positive value indicates that flooding (drought) promotes growth or competitive effect while negative value indicates a detrimental effect of flooding (drought) on growth or competitive effect. Species name for which the trend is significant appear in bold and is underlined. For <i>Agrostis stolonifera</i>, growth and competitive effect are reported with the model run with four different species for which the initials appear in subscript (A.sto_Lp, A.sto_Cc, A.sto_Jg, A.sto_Gf).</p

Importance of competition for each species along the flooding gradient with an initial cover of species, i, j and k: 1, 1, 0.

<p>The importance of competition represents the proportion of change in ecological success caused by competition relative to environmental conditions. The SEVa was calculated following [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130152#pone.0130152.ref011" target="_blank">11</a>] and expressed as cm.day-1. Fig 2 reports the results for <i>Agrostis stolonifera</i> modeled in pair with <i>Lolium perenne</i> (Fig 2a), <i>Cynosurus cristatus</i> (Fig 2b), <i>Juncus gerardi</i> (Fig 2c), <i>Glyceria fluitans</i> (Fig 2d). Results for <i>Lolium perenne</i> are reported in Fig 2a’, <i>for Cynosurus cristatus</i> in Fig 2b’, for <i>Juncus gerardi</i> in Fig 2c’ and for <i>Glyceria fluitans</i> in Fig 2d’.</p