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61.
The fossil South American ungulates are of great interest relative to the new phylogenetic framework elaborated for living placental mammals. In particular, studies on these endemic taxa can allow for testing congruence between southern placental phylogeny and plate tectonics, beyond what has already been suggested in the Atlantogenata hypothesis based on extant afrotherians and xenarthrans. The presence of delayed dental eruption relative to skull growth is one feature characterizing the extant afrotherians and possibly the xenarthrans. Late dental eruption has been mentioned previously in South American notoungulates, thus suggesting possible resemblance with afrotherians and perhaps xenarthrans. We provide here a detailed study of the dental eruption pattern relative to the skull growth in the notoungulates. In contrast to previous statements, our results demonstrate that there is currently no evidence for an afrotherian-like delayed dental eruption in this group. For now, the inferred absence of a delayed dental eruption in notoungulates does not support atlantogenatan/afrotherian affinities for the Notoungulata, but other atlantogenatan/afrotherian characteristics remain to be explored in more detail in this group and other South American ungulates. 相似文献
62.
A Spatially Explicit Resource-Based Approach for Managing Stream Fishes in Riverscapes 总被引:1,自引:0,他引:1
The article describes a riverscape approach based on landscape ecology concepts, which aims at studying the multiscale relationships
between the spatial pattern of stream fish habitat patches and processes depending on fish movements. A review of the literature
shows that few operational methods are available to study this relationship due to multiple methodological and practical challenges
inherent to underwater environments. We illustrated the approach with literature data on a cyprinid species (Barbus barbus) and an actual riverscape of the Seine River, France. We represented the underwater environment of fishes for different discharges
using two-dimensional geographic information system-based maps of the resource habitat patches, defined according to activities
(feeding, resting, and spawning). To quantify spatial patterns at nested levels (resource habitat patch, daily activities
area, subpopulation area), we calculated their composition, configuration, complementation, and connectivity with multiple
spatial analysis methods: patch metrics, moving-window analysis, and least cost modeling. The proximity index allowed us to
evaluate habitat patches of relatively great value, depending on their spatial context, which contributes to the setting of
preservation policies. The methods presented to delimit potential daily activities areas and subpopulation areas showed the
potential gaps in the biological connectivity of the reach. These methods provided some space for action in restoration schemes. 相似文献
63.
Guillaume Rieucau William L. Vickery G. Jean Doucet 《Behavioral ecology and sociobiology》2009,63(6):891-897
The giving-up density of food (GUD), the amount of food remaining in a patch when a forager ceases foraging there, can be
used to compare the costs of foraging in different food patches. But, to draw inferences from GUDs, specific effects of foraging
costs (predation risk, metabolic and missed opportunities costs) on GUDs have to be identified. As high predation risk, high
metabolic costs and abundant food all should produce high GUDs, this does not allow us to infer directly the quality of a
habitat. In order to separate the effect of each foraging cost, we developed an optimal foraging model based on food supplementation.
We illustrate the use of our model in a study where we assessed the impact of a power line right-of-way in a white-tailed
deer (Odocoileus virginianus) winter yard by determining whether the negative effects of cover loss outweigh the positive effects of browse regeneration. 相似文献
64.
Lopareva-Pohu A Verdin A Garçon G Lounès-Hadj Sahraoui A Pourrut B Debiane D Waterlot C Laruelle F Bidar G Douay F Shirali P 《Environmental pollution (Barking, Essex : 1987)》2011,159(6):1721-1729
Due to anthropogenic activities, large extends of soils are highly contaminated by Metal Trace Element (MTE). Aided phytostabilisation aims to establish a vegetation cover in order to promote in situ immobilisation of trace elements by combining the use of metal-tolerant plants and inexpensive mineral or organic soil amendments. Eight years after Coal Fly Ash (CFA) soil amendment, MTE bioavailability and uptake by two plants, Lolium perenne and Trifolium repens, were evaluated, as some biological markers reflecting physiological stress. Results showed that the two plant species under study were suitable to reduce the mobility and the availability of these elements. Moreover, the plant growth was better on CFA amended MTE-contaminated soils, and the plant sensitivity to MTE-induced physiological stress, as studied through photosynthetic pigment contents and oxidative damage was lower or similar. In conclusion, these results supported the usefulness of aided phytostabilisation of MTE-highly contaminated soils. 相似文献
65.
It has been widely acknowledged that people’s beliefs and perceptions influence implementation of climate change adaptation. Regarding perception barriers, some authors keep highlighting the confused definition of adaptation and its various interpretations. Our research contributes to this area by exploring how adaptation to climate change is perceived through 83 semi-structured interviews with stakeholders (public and municipal organizations, ENGO, private sector) from Montreal and Paris. Our results demonstrate a mirror opposition in the perception of adaptation to climate change. Indeed, while several respondents interpreted adaptation as a resignation, many interviewees perceived adaptation as an opportunity. The analysis showed that adaptation referring to resignation includes the ideas of a non-action and detrimental to mitigation; an excuse for not changing; anxiety about climate change; fatalism; and human failure. Adaptation perceived as an opportunity is divided into a source of creativity; toward sustainable development; led by the emergency; and awareness and making society of its responsibilities. Our findings confirm that terminological ambiguity of the term “adaptation” has to be considered in the decision-making process, which can be influenced by the perception of stakeholders. 相似文献
66.
Marc Crampon Yoann Copard Guillaume Favreau Julie Raux Nadine Merlet-Machour Mathieu Le Coz Maïmouna Ibrahim Valérie Peulon-Agasse Florence Portet-Koltalo 《Environmental science and pollution research international》2014,21(18):10601-10613
Increased use of agrochemical products to improve yields for irrigated crops in sub-Saharan Africa has been accompanied by a significant increase in the risk of environmental contamination. Detailed examples of the fate of pesticides after initial spreading on crop fields are scarce in tropical regions, where safe practices and related health risks are poorly understood by smallholder farmers. In the semi-arid environment of the Lake Chad Basin, SE Niger, both intrinsic properties of pesticides and extrinsic factors such as soil and climate helped to characterize processes leading to an accumulation of pesticides in soils. Analysis by HPLC-UV of a 6 m deep soil profile showed the presence of Paraquat at concentrations from 953?±?102 μg kg?1 to 3083?±?175 μg kg?1 at depths between 0.80 and 2.75 m below the land surface. Soil analysis revealed that up to approximately 15 % of the total soil matrix consists of smectites, a clay mineral capable of retaining cationic pesticides such as Paraquat, and a very low content of organic matter (<0.15 wt.% TOC). Paraquat could be stored and not bioavailable in a clayey barrier at approximately 2-m depth and therefore does not represent an immediate risk for populations or environment in this form. However, if the Paraquat application rate remains constant, the clayey barrier could reach a saturation limit within 150–200 years and 180–220 years if we consider a DT50 in soil of ~1,000 days (FAO). Consequently, it could lead to a deeper infiltration and so a pollution of groundwater. Such a scenario can represent a health risk for drinking water and for the Lake Chad, which is a major resource for this densely populated region of semi-arid Africa. Further analyses should focus on deeper layers and groundwater Paraquat contents to validate or invalidate the hypothesis of storage in this clay-rich layer. 相似文献
67.
Shannon Hagerman Terre Satterfield Sara Nawaz Guillaume Peterson St-Laurent Robert Kozak Robin Gregory 《Conservation biology》2021,35(6):1932-1943
Novel management interventions intended to mitigate the impacts of climate change on biodiversity are increasingly being considered by scientists and practitioners. However, resistance to more transformative interventions remains common across both specialist and lay communities and is generally assumed to be strongly entrenched. We used a decision-pathways survey of the public in Canada and the United States (n = 1490) to test two propositions relating to climate-motivated interventions for conservation: most public groups are uncomfortable with interventionist options for conserving biodiversity and given the strong values basis for preferences regarding biodiversity and natural systems more broadly, people are unlikely to change their minds. Our pathways design tested and retested levels of comfort with interventions for forest ecosystems at three different points in the survey. Comfort was reexamined given different nudges (including new information from trusted experts) and in reference to a particular species (bristlecone pine [Pinus longaeva]). In contrast with expectations of public unease, baseline levels of public comfort with climate interventions in forests was moderately high (46% comfortable) and increased further when respondents were given new information and the opportunity to change their choice after consideration of a particular species. People who were initially comfortable with interventions tended to remain so (79%), whereas 42% of those who were initially uncomfortable and 40% of those who were uncertain shifted to comfortable by the end of the survey. In short and across questions, comfort levels with interventions were high, and where discomfort or uncertainty existed, such positions did not appear to be strongly held. We argue that a new decision logic, one based on anthropogenic responsibility, is beginning to replace a default reluctance to intervene with nature. 相似文献
68.
This study examined whether adding spin to a ball in the free kick situation in football affects a professional footballer’s
perception of the ball’s future arrival position. Using a virtual reality set-up, participants observed the flight paths of
aerodynamically realistic free kicks with (±600 rpm) and without sidespin. With the viewpoint being fixed in the centre of
the goal, participants had to judge whether the ball would have ended up in the goal or not. Results show that trajectories
influenced by the Magnus force caused by sidespin gave rise to a significant shift in the percentage of goal responses. The
resulting acceleration that causes the ball to continually change its heading direction as the trajectory unfolds does not
seem to be taken into account by the participants when making goal judgments. We conclude that the visual system is not attuned
to such accelerated motion, which may explain why goalkeepers appear to misjudge the future arrival point of such curved free
kicks.
Electronic Supplementary Material Supplementary material is available for this article at . 相似文献
69.
The concept of environmental innovation strategies (EIS) is introduced and discussed. The notion refers to the conduct by which non-governmental organisations (NGOs) act as policy entrepreneurs seeking to address environmental issues by going beyond the provisions of public regulations. Environmental innovation is understood as the product of a process of social interactions between heterogeneous types of actors, including NGOs. Three social mechanisms are introduced in order to capture the conditions enabling and motivating NGOs to pursue EIS, as well as the politics through which EIS are produced. These mechanisms are then discussed in the light of two in-depth case studies in Indonesia and Switzerland. The findings highlight the institutional frustration and mix of concerns that push NGOs to engage in EIS, as well as the non-spontaneous nature of environmental innovations. Innovation represents, in the end, a game of power that should be analysed as such. 相似文献
70.
Ole Mertz Kenneth Grogan Dirk Pflugmacher Guillaume Lestrelin Jean-Christophe Castella Thoumthone Vongvisouk 《Journal of Land Use Science》2018,13(1-2):1-15
Forest reference levels (FRLs) provide a benchmark for assessing reduced emissions from deforestation and forest degradation (REDD+), and they are central to demonstrate additionality of REDD+. Attaining realistic FRLs, however, is challenging, especially in complex mosaic landscapes. We established FRLs in northern Laos for different reference periods and tested them against actual carbon stock changes. Annual time series of Landsat satellite images were used to capture the subtle changes in carbon stocks in complex landscapes characterized by shifting cultivation. We found that FRLs differ considerably depending on the reference period chosen. Abrupt land-use changes occurred when hybrid maize replaced traditional shifting cultivation and forests, and this invalidated carbon stock trends that would have been predicted had the FRL been projected into the future. We conclude that demonstrating additionality of REDD+ in fast developing areas is difficult and that payment systems rewarding potential emission reductions against hypothetical extrapolation of FRLs are unlikely to be a cost-effective strategy. 相似文献