Environmental and climate changes

Top PDF Environmental and climate changes:

Holocene environmental history of a small Mediterranean island in response to sea-level changes, climate and human impact

Holocene environmental history of a small Mediterranean island in response to sea-level changes, climate and human impact

2 1. Introduction During the Holocene, the Mediterranean region was deeply affected by environmental changes resulting from a complex history of human land-use and climatic interactions (e.g., de Beaulieu et al., 2005; Jalut et al., 2009; Roberts et al., 2004; Walsh, 2014). The study of these interactions in insular contexts is pertinent since these marginal territories constitute simplified ecosystems where ecological and species dynamics could be more easily understood (Whittaker and Fernández-Palacios, 2007). For this reason islands are classically considered as ‘laboratories’ for the study of biodiversity structure and dynamics. Islands are also fragile systems, highly vulnerable to rapid environmental changes and anthropic pressure. Since the 1990s, studies based on pollen analysis aiming to reconstruct the impact of human activities and climate changes on Mediterranean islands have increased, but most are focused on large islands such as the Balearic Islands (Burjachs et al., 1994; Yll et al., 1997), Malta (Carroll et al., 2012; Djamali et al., 2012; Gambin et al., 2016), Sardinia (Beffa et al., 2015; Di Rita and Melis, 2013) or Sicily (Noti et al., 2009; Tinner et al., 2009). In Corsica, the vegetation history is quite well known from various palynological analyses carried out on high-altitude sites (Reille, 1975, 1977, 1988a, 1988b; Reille et al., 1997, 1999) and on coastal marshes (Currá et al., 2016; Reille, 1984, 1988b, 1988c, 1992a). These studies highlight the major role of human activities as drivers of vegetation landscape dynamics since the Neolithic period (ca. 7600 cal. yr B.P.). However, small (i.e. <1000 ha) and medium Mediterranean islands are still under-investigated (but see Avramidis et al., 2013; Calò et al., 2013; Pavlopoulos et al., 2010), because holocene sedimentary deposits are rare. For exemple in Corsica little or no information is available about palaeoenvironmental history of the numerous small peripheral islands (c. 145 islands and islets according to Guillemette, 2015) beyond the past few centuries (Vigne, 1994). Yet, these simplified ecosystems are especially suitable to study the complex relationships between environment, sea-level changes and human practices: in general, low-elevation islands are sensitive to sea-level variations whereas small islands could be sensitive to land-use changes (Bass and Dalal-Clayton, 1995).
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Recording environmental changes in Chilean lacustrine sediments during the last millenium: Natural climate variability and human impact

Recording environmental changes in Chilean lacustrine sediments during the last millenium: Natural climate variability and human impact

Recording environmental changes in Chilean lacustrine sediments during the last millenium: Natural climate variability and human impact. L. Nuttin (1), N. Fagel (1), S. Bertrand (2), S. Schmidt (3), A. Araneda (4,5), F. Torrejon (4,5), and R. Urrutia (4,5)

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Insect evidence for environmental and climate changes from Younger Dryas to Sub-Boreal in a river floodplain at St-Momelin (St-Omer basin, northern France), Coleoptera and Trichoptera.

Insect evidence for environmental and climate changes from Younger Dryas to Sub-Boreal in a river floodplain at St-Momelin (St-Omer basin, northern France), Coleoptera and Trichoptera.

fauna is enigmatic primarily because insects have almost never become adapted to the fully marine environment. Although there are a few scarce beetle species in these fossil assemblages that indicate saline habitats, none of the faunas are typical of the salt marsh community. Whereas transgressions are not associated with any positive evidence of marine influences, the Sub-Boreal marine regression, on the other hand, is associated with a spectacular increase in taxonomic diversity and strong evidence for the increased rate of flow of the river Aa. Mutual Climatic Range estimates on the palaeotem- perature of the Younger Dryas period in Northern France indicate that mean July values were near to 10 °C and associated with cold, rather continental winters. The transi- tion to the Holocene was abrupt and intense with the immediate establishment of mean July temperatures of about 16 °C, that is equivalent to present day summer warmth. These figures for the thermal climatic history of Northern France complement those already obtained for the Lateglacial interstadial MCR figures from beetle assem- blages in the Paris Basin. The climatic history for Northern France has here been extended into the middle Holocene. It has not been possible yet to quantify the rate at which climatic warming took place at the transition from the Lateglacial to the Holocene, apart from recognising that it was very sudden and intense. Because the depo- sition of the sedimentary sequence has been rapid, the St-Omer basin should provide an opportunity for a more detailed investigation into its sedimentology and biostratigraphy and a resolution to the important problem of how fast the European climate can change.
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A 500-yr record of Northern Patagonian environmental changes: Lago Plomo and Lago Bertrand

A 500-yr record of Northern Patagonian environmental changes: Lago Plomo and Lago Bertrand

We study the sedimentary records of two interconnected lakes from Chilean Patagonia (46.5°S 72.5°W). Lake Betrand is adjacent to the pr o-glacial lake, Lake Plomo. The connection between both lakes is limited by a morainic barrier. The coring sites were selected after a bathymetric survey using an echo-sounder. Short cores were retrieved in 2009 using a gravity corer. For Lake Plomo radiocarbon, 210 Pb and 137 Cs data are consistent with a constant accumulation range of 2 mm/yr. 210 Pb data support a lower sedimentation rate for Lake Betrand. To reconstruct past climate changes, we conduct a multiproxy study combining sedimentology and geochemistry. Lake Plomo sediments are made by light brown silts with 20% of clay but no sand. X-ray radiographies demonstrate that the sediment is finely laminated, rich in organic macro-remains. The C/N ratio is stable, the average value of 15 supports the important terrestrial supply to the lake. The organic content of the sediment, calculated from 550°C loss of ignition, represent a few percents. The biogenic silica content of the sediment, estimated by atomic absorption after NaOH leaching, is very low (<5%). Microscopic slides reveal the sparse occurrence of small 6 to 10 µ m diatoms. The Plomo sedimentary record contrasts with the adjacant lacustrine record, Lake Betrand. The sediment is made by homogeneous silts with some clays (< 20%) and 5 to 10% of sand. Lake Betrand is characterized by lower C/N ratio (10) supporting a more important aquatic productivity. Diatoms are abundant and larger in size (50-100 µ m). The biogenic silica profile evidences two peaks (Si bio>30%) above a 5% background level. They probably record a major climate change in North Patagonian Andes. Even further sedimentological and geochemical analyses are in progress our observations evidence the potential of such lacustrine records to reconstruct the Last Millennium climate changes in North Patagonia. This research is funded by Chilean Fondecyt project number 1070508 and Belgian projects (FNRS proposal 1360 2007-2010, ULg CFRA 1060 2009-2010).
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Achieving Global Climate and Environmental Goals by Governmental Regulatory Targeting

Achieving Global Climate and Environmental Goals by Governmental Regulatory Targeting

3. Strategic Niche Management and Transition Management The concept of strategic niche management (SNM) emerged from the two opposing views of the technological fix ideology (or technological optimism) and the cultural fix paradigm ( Hoogma et al., 2002 ). The former argues that the bene fits associated with technological progress are likely to far outweigh costs, and that a technological solution can be found to all problems. The latter suggests that the technology itself is actually part of the problem and that real solutions will have to come from social and cultural change. Therefore, SNM was created to “allow for working on both the technical and the social side in a simultaneous and coherent manner ” ( Hoogma et al., 2002 , p. 3). The related concept of transition management (TM) is discussed later in this section. SNM and TM are only two of several possible theories of sustainable transi- tions/transformations we have chosen to discuss – see Feola (2015) – because they have captured the attention of Dutch and EU industrial policy, especially regarding energy, and because they heavily envision the involvement of incumbents and would (in our view as explained more fully later) require too long a time to yield the necessary radical technological and social changes to be useful. A useful and thorough treatment of the history of SNM and TM is provided by Loorbach et al. (2017) .
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Environmental and trophic determinism of fruit abscission and outlook with climate change in tropical regions

Environmental and trophic determinism of fruit abscission and outlook with climate change in tropical regions

Fruit abscission may be particularly sensitive to changes in envi- ronmental conditions, given that this developmentally regulated pro- cess must occur under the appropriate conditions and at the right time to ultimately allow seed dispersal and species survival. If fruit are shed prematurely, that is, before seed and embryo maturation are complete, or too late in relation to seasonal climate changes, reproductive suc- cess may be jeopardized. While it is clear that environmental factors have consequences for organ loss, it is not yet clear at which stages in the abscission process the environmental variables are sensed. The separation of an organ from the plant body takes place in cells in a specialized abscission zone (AZ). Based on studies using model plants including Arabidopsis thaliana and tomato, the process of organ ab- scission can be divided into four main steps: (a) the differentiation of AZ cells, which eventually (b) acquire the competence to respond to abscission signals and initiate cellular responses, which in due course, lead to (c) cell wall remodeling and cell wall degradation, and result in cell separation between adjacent AZ cell layers and fruit drop, and finally, (d) the transdifferentiation of a protective layer on the proxi- mal side of the AZ (Aalen, Wildhagen, Sto, & Butenko, 2013; Estornell, Agusti, Merelo, Talon, & Tadeo, 2013; Meir et al., 2019). During this highly coordinated sequence of events, the cellular responses in the AZ include changes to molecular, metabolic, and structural cell com- ponents. However, environmental factors that can initiate the ab- scission process and control abscission execution, which includes the activation of signaling and regulatory factors that control the expres- sion of cell wall hydrolytic enzymes, are not well known, and to date, studies have focused on only a few crop and model species such as apple, tomato, citrus, and Arabidopsis (Botton et al., 2011; Estornell et al., 2013; Meir et al., 2010; Roberts, Elliott, & Gonzalez-Carranza, 2002). Interestingly, a recent molecular study on drought-induced leaf abscission in Arabidopsis indicated that the signaling pathways are sim- ilar to those identified in Arabidopsis floral organ abscission (Patharkar & Walker, 2016). However, studies on how the environment affects organ abscission of perennial crops is complicated by the size of the plants and by the difficulty involved in growing them in controlled con- ditions, and so whether the same pathways function in all abscission systems remains to be determined (Yu, Hu, Doust, & Kellogg, 2019). One way to circumvent the problem of controlled environmental con- ditions is to perform studies which take advantage of natural seasonal variations that occur over a period of years.
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Environmental Changes

Environmental Changes

This is particularly remarkable in the case of climate change. When it became clear in Copenhagen in 2009, that the UNFCCC regime based on burden-sharing between rich and poor countries did not perform, a decision was taken to complete it with an action agenda gathering non-state actors, private investors and cities in partic- ular. The success of the Paris Agreement on climate change (2016) lies as much in the dynamic of UNFCCC diplomats as in the open and transparent negotiation platform, imagined to further tie diplomacy and the real economy. The particular regime that came out of this platform expands beyond the limits of the UNFCCC regime it super- seded. The Paris Agreement, which is the hallmark and bedrock of this new climate regime, can be best defined as dynamic, flexible and hybrid. As Laurence Tubiana, France’s chief ambassador for climate change explained (Henry and Tubiana, 2018: 13), ‘The number and complexity of drivers made a top down regime working through central coordination mechanism almost impossible to achieve’. Therefore, the agreement needed to make room simul- taneously for the notion that development choices are “nationally determined”’, for the need to have a collective mechanism to measure, review and verify (the transpar- ency framework), the recognition of the inadequacy of the Kyoto concept and the need to get out of burden sharing and car- bon budgets. There are virtually no outsid- ers to the Paris Agreement climate regime, even after the United States decided to withdraw; US firms and federal states are identified players of it, even though they are not parties to it. The double motion of hori- zontal diffusion and vertical institutionali- zation, which characterises the evolution of the Rio meta-regime, is also at play within its subparts, in a sort of fractal replication.
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Environmental effects of climate change impacts on European wood species vulnerability

Environmental effects of climate change impacts on European wood species vulnerability

Wood is considered as an orthotropic hydro-mechanical material whose mechanical behavior strongly depends on the moisture content and the temperature. Taking into account humidity and temperature variation, the mechanical behavior assessment becomes more complex due to the coupling effect between the mechanical stress and the hydric state (thermos-hydro-mechanical behavior (THM)) [Moutou Pitti et al. (2010); Hamdi et al. (2017)]. The viscoelastic behavior of wood under variable humidity, known as the mechano-sorption behavior, induces different responses in the drying and in the humidification phase. However, in presence of climatic variations, the long terms load and especially the crack initiations, the mechanical behavior of wooden structures is found highly modified, disturbing their implementation and shortening their life in service. The effects of moisture changes on the propagation of cracks are not yet clearly identified. Therefore, it appears necessary to investigate the influence of the variable environment and crack growth process on the mechanical properties of wood structures.
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Essays on climate policy, trade and competitiveness : three essays in applied environmental economics

Essays on climate policy, trade and competitiveness : three essays in applied environmental economics

This political difficulty of generating meaningful economic incentives for decarbonisation in an ETS is partly a European problem – given the challenge of agreeing between 27 or 28 different member states with very different economic and emissions profiles. However, the EU is not alone in this. Other countries such as Japan, progressive states of the United States and Canada, and Australia and New Zealand – all once hailed as likely to follow the EU into the emissions trading club – have since seen early progress towards ETS markets slow or reverse. This phenomenon has various causes. However, in this author’s opinion a common factor across many of these cases is that carbon pricing and emissions trading schemes in particular ignore fundamental political economy concerns of key stakeholders. Most notably, they are typically implemented with a focus on their “technological neutrality” and “economic optimality for society as a whole”, but policy makers then give little attention to the revolutionary structural changes that are being required of industries to completely change their technology, capital stock and business models. Thus, ETSs are often introduced without an accompanying narrative or vision of how specific energy intensive industries can transform themselves to survive and be profitable in a decarbonised world. Not surprisingly, they are thus perceived by industry as punitive measures that are a direct attack on their ability to survive and perform financially.
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Climate-driven changes in coastal marine systems of western Europe

Climate-driven changes in coastal marine systems of western Europe

the Mediterranean Sea. At the beginning of the pro- gramme, the sampling sites were chosen because they reflected the diversity of systems along the French coasts (e.g. marine, estuarine and mixed systems). In practical terms, the choice of sampling sites was driven by (1) their local or regional environmental benefits, (2) the existence of historical biological or hydro-climatic monitoring and (3) the accessibility for regular sam- pling and for possible automation in the measurement of some parameters. Coastal systems studied under this programme have a variety of hydro-climatic char- acteristics ranging from the non-tidal Mediterranean Sea (e.g. Marseille) to the mega-tidal English Channel (Wimereux, see Fig. 1). Sampling has been carried out at least twice a month since 1997. A protocol has been established so that sampling is carried out at all sta- tions at sub-surface and at high tide (for the tidal seas). More details on the monitoring are available at http:// somlit.epoc.u-bordeaux1.fr/fr. All data gathered by this programme were considered in this study. It is important to note that because of dependency on meteorological conditions during sampling, the per- centage of available data is not always the optimum (Tables 1 & 2).
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Editorial: Biogeochemical Responses of Tropical Ecosystems to Environmental Changes

Editorial: Biogeochemical Responses of Tropical Ecosystems to Environmental Changes

Mangrove biogeochemical response to climate change Over 1,200 publications between 1990 and 2018 refer to “Mangrove & Climate Change”. Most however, discusses eventual impacts and scenarios that might occur in the future, based on projections and modelling. Unfortunately, however, this approach inherits two major constrains that make them extremely difficult to support local and regional scale governance aiming adaptation and mitigation of climate change impacts to coastal regions. First, these scenarios and modeling exercises are based on scarce empirical data. Even worst, most data supporting them are generated from mangroves located near their latitudinal limits or obtained under greenhouse-controlled conditions, far from nature’s reality. Second, they consider impacts that may occur in the future, whereas they are actually happening today in many significant mangrove-dominated areas. Less than 5% of those 1,200 publications actually discuss observed, quantified impacts, even considering among them the nearly half that deals with controlled laboratory or greenhouse experiments. This present discussion deals with these 5%. For a general appraisal of the mangrove vs climate change issues one is referred to at least four recent, outstanding reviews summarizing future scenarios and aspects of climate change impacts on mangroves (Alongi, 2015; Ward et al., 2016; Jennerham et al., 2017; Makowski, 2018).
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Looking at birds to make sense of climate change and of other changes too...?

Looking at birds to make sense of climate change and of other changes too...?

cover and land-uses changes: environmental and sociological changes can not be dissociated,  Residents in protected and rural area do not know more species than the urban residents but have a more detailed knowledge of the species features due to agricultural connexions to the land and its biodiversity.

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A population facing climate change: joint influences of Allee effects and environmental boundary geometry

A population facing climate change: joint influences of Allee effects and environmental boundary geometry

54 bd Raspail 75270 Paris Cedex 06, France * Corresponding author. E-mail: lionel.roques@avignon.inra.fr Abstract As a result of climate change, many populations have to modify their range to follow the suitable areas - their “climate envelope” - often risk- ing extinction. During this migration process, they may face absolute boundaries to dispersal, because of external environmental factors. Con- sequently, not only the position, but also the shape of the climate envelope can be modified. We use a reaction-diffusion model to analyse the effects on population persistence of simultaneous changes in the climate envelope position and shape. When the growth term is of logistic type, we show that extinction and persistence are principally conditioned by the species mobility and the speed of climate change, but not by the shape of the climate envelope. However, with a growth term taking an Allee effect into account, we find a high sensitivity to the variations of the shape of the climate envelope. In this case, the species which have a high mobility, although they could more easily follow the migration of the climate enve- lope, would be at risk of extinction when encountering a local narrowing of the boundary geometry. This effect can be attenuated by a progressive opening of the available space at the exit of the narrowing, even though it transiently leads to a diminished area of the climate envelope.
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Link between European and North Atlantic abrupt climate changes over the last glaciation

Link between European and North Atlantic abrupt climate changes over the last glaciation

observed as in the previously described profiles P1 to P3. The fine pedostratigraphic analysis shows an alternation of loess layers, from cold and relatively dry climate conditions, with more or less developed paleosols, indicating periods of a relatively increased humidity (Figure 2). Some of the loess units show millimetric sandy laminations resembling those observed in other Western European loess sequences [Antoine et al., 2001], pointing to episodes of a strong wind. The soil units are clearly expressed: a cambisol (LB) and tundra gley horizons (G1 to G7) already seen in the previous Nussloch profiles, as well as four new incipient gley layers (IG5b, IG6b, IG8a,b, IG9a,b). Some of the tundra gleys (i.e., soils formed under poor drainage), as G1 or G3&G4, show surface deformations due to freeze- thaw processes. This indicates that during their formation the climate was still cold, as confirmed by the malacological analysis [Moine, 2003].
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Constraining Climate Model Parameters from Observed 20th Century Changes

Constraining Climate Model Parameters from Observed 20th Century Changes

1 INTRODUCTION The recognition that anthropogenic activity is causing global warming (Houghton et al., 2001; Solomon et al., 2007) has emphasized the importance of developing climate models with predictive capability. In recent decades considerable effort has been devoted to evaluating state-of-the-art climate models from this point of view. A good summary of this work is given in Chapter 8 of the latest IPCC report (Randall et al., 2007). Much of the work has focused on evaluating the models’ ability to simulate the annual mean state, the seasonal cycle, and the inter-annual variability of the climate system, since good data is available for evaluating these aspects of the climate system. However good simulations of these aspects do not guarantee a good prediction. For example, Stainforth et al. (2005) have shown that many different combinations of uncertain model sub-grid scale parameters can lead to good simulations of global mean surface temperature, but do not lead to a robust result for the model’s climate sensitivity.
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Street trees in Paris are sensitive to spring and autumn precipitation and recent climate changes

Street trees in Paris are sensitive to spring and autumn precipitation and recent climate changes

Climate-growth analysis and pointer years Correlation analyses were performed to assess tree growth response to climatic conditions. When all trees from streets and parks were considered, the EPS value for the period 1970–2013 was above the 0.85 critical threshold (0.89; Table 1 ). In consequence, bootstrapped correlations coeffi- cients (BCC) calculations were performed on the entire sam- pled population of silver lindens in Paris City. In this proce- dure, standardized chronologies were correlated to time series of monthly mean temperatures, monthly sum of precipitation, monthly mean PET and monthly mean total daily radiations from September of the previous year (namely n-1) to November of the current year (namely n), period limiting the growing season for silver lindens in Paris. A bootstrap method had to be used due to the non-independence of tree rings within each individual tree. The program estimated BCC at the end of 1000 re-sampling of a random selection of 11 years during the 1970 –2013 period to detect significance level (95% of BCC significant with a p-value <0.05; Guiot 1991 ) accord- ing to two different methods. First, BCC calculation round was performed considering the entire temporal window 1970–2013 (Blasing et al. 1984 ) for precipitation and temper- ature and from 1978 to 2013 for PET and total radiation. Second, BCC were calculated with year-to-year moving methods. A temporal window of 30 years was the best com- promise that we could make for such a short period as 1970– 2013. This allowed detecting temporal instability of the rela- tion between intra-annual climatic factors and growth (Biondi and Waikul 2004 ).
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Detecting changes in forced climate attractors with Wasserstein distance

Detecting changes in forced climate attractors with Wasserstein distance

Consistently with Drótos et al. (2015), we take 5τ = 5 × 73 (i.e., 5 cycles, but we have checked than τ is enough). Both systems are dissipative outside of the attractors neighbor- hood, therefore all N trajectories collapse to the attractors after time 5τ and provide an efficient sampling of the invari- ant measure (Romeiras et al., 1990). After time 5τ, the set of N final points emerging of N initial conditions is called a snapshot attractor (see Algorithm 2). Snapshot attractors are special cases of pullback attractors (Chekroun et al., 2011). The latter class requires an integration between −∞ and a desired final time. Equation (2) does not depend on time; therefore, the integration into Sect. 3.1 can be performed on any length intervals.
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Anopheles number prediction on environmental and climate variables using Lasso and stratified two levels cross validation

Anopheles number prediction on environmental and climate variables using Lasso and stratified two levels cross validation

Conclusion In this work, we implemented an algorithm for the prediction of malaria risk us- ing environmental and climate variables. We performed the variables selection using an automatic machine learning by a method combining Lasso and strat- ified two levels cross validation. The selected variables were debiased and the prediction was achieved by simple GLM. The results obtained by such procedure are clearly better improved compared to those obtained by the B-GLM method taken as the reference method. The improvement concerns all properties such as the quality of the selection and prediction. Moreover, the pre-treatments of experts were overcome and the CPU time used to display our program is smaller than the one required by the reference method.
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Past climate changes and the role of refugia in the temperate Northern Hemisphere

Past climate changes and the role of refugia in the temperate Northern Hemisphere

Potential contribution of modern refugia to future biodiversity Genetic studies have shown that glacial refugia do not necessarily harbor the most diverse populations. However, the post- glacial crossing of different lineages of the same species during the recolonization process from multiple refugia produced the most genetically diverse populations (petit et al. 2003). Thus, even if the genetic diversity of a population tends to decrease over time when a species remains isolated in a refugium, its persistence into multiple scat- tered refugia may contribute to conserving and improving future species diversity. The future persistence of different species under the ongoing global warming and the pres- ervation of biodiversity might well depend on the identification of potential modern
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Can context changes improve behavioral flexibility? Towards a better understanding of species adaptability to environmental changes

Can context changes improve behavioral flexibility? Towards a better understanding of species adaptability to environmental changes

Aurélie Coulon (2019) Can context changes improve behavioral flexibility? Towards a better understanding of species adaptability to environmental changes. Peer Community in Ecology, 100019. 10.24072/pci.ecology.100019 Behavioral flexibility is a key for species adaptation to new environments. Predicting species responses to new contexts hence requires knowledge on the amount to and conditions in which behavior can be flexible. This is what Logan and collaborators propose to assess in a series of experiments on the great-tailed
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