Articles de revues : « Climatic constraints »

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Lazaridi, Efstathia, et Penelope J. Bebeli. « Cowpea Constraints and Breeding in Europe ». Plants 12, n^o 6 (16 mars 2023) : 1339. http://dx.doi.org/10.3390/plants12061339.

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Cowpea (Vigna unguiculata (L.) Walp.) is a legume with a constant rate of cultivation in Southern European countries. Consumer demand for cowpea worldwide is rising due to its nutritional content, while Europe is constantly attempting to reduce the deficit in the production of pulses and invest in new, healthy food market products. Although the climatic conditions that prevail in Europe are not so harsh in terms of heat and drought as in the tropical climates where cowpea is mainly cultivated, cowpea confronts with a plethora of abiotic and biotic stresses and yield-limiting factors in Southern European countries. In this paper, we summarize the main constraints for cowpea cultivation in Europe and the breeding methods that have been or can be used. A special mention is made of the availability plant genetic resources (PGRs) and their potential for breeding purposes, aiming to promote more sustainable cropping systems as climatic shifts become more frequent and fiercer, and environmental degradation expands worldwide.

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Bhattacharjya, Birendra Kumar, Anil Kumar Yadav, Dipesh Debnath, Bhaskar Jyoti Saud, Vinod Kumar Verma, Sona Yengkokpam, Uttam Kumar Sarkar et Basanta Kumar Das. « Effect of extreme climatic events on fish seed production in Lower Brahmaputra Valley, Assam, India : Constraint analysis and adaptive strategies ». Aquatic Ecosystem Health & ; Management 24, n^o 3 (1 juillet 2021) : 39–46. http://dx.doi.org/10.14321/aehm.024.03.06.

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Abstract The climate of Brahmaputra valley (located in the North-eastern Indian state of Assam) witnesses considerable changes with sub-tropical rain-storm atmosphere and has four well-defined seasons (monsoon, post-monsoon, winter and pre-monsoon) in a year. The state is experiencing extreme climatic events like erratic rainfall patterns (causing abnormally high floods) and drought-like situations in recent years, which adversely affects fish seed production thereby affecting pond aquaculture and fisheries enhancements in open-waters of the region. The present paper describes the major constraints faced by fish seed producers of the region because of extreme climatic events (abnormally high floods and prolonged dry spells) based on field studies in 27 fish seed production farms (randomly selected) located in three districts of Lower Brahmaputra Valley Zone of Assam, India. Primary data on different aspects of constraints faced by the fish seed producers because of extreme climatic events were collected and analysed. Rank Based Quotient values were calculated, based on ranks given by the fish seed producers for each constraint to prioritize them. Dominant constraint related to abnormally high floods faced by the fish seed producers was ‘loss of brood stock’ (Rank based quotient = 99.1) whereas the least important constraint was ‘entry of weeds/macrophytes’ during floods (Rank Based Quotient = 25.5). Constraints related to drought-like situations ranged from the least important ones like ‘low milt production of male brood fishes’ that had the lowest value (12.5) to the over-arching constraint of ‘inadequate water depth in fish ponds’ during pre-monsoon and prolonged dry spells (Rank Based Quotient = 100.0). Adaptive strategies developed by fish seed producers of the study region to overcome the major constraints have been outlined in the paper. The need for developing improved risk management at macro-level through appropriate policy support to fish seed producers in the fish-deficit region and suggested policy support measures for ensuring sustainability are discussed.

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Moomen, Abdul-Wadood. « AIR TRANSPORT IN GHANA : SOME CLIMATIC CONSTRAINTS ». Aviation 16, n^o 3 (2 octobre 2012) : 88–95. http://dx.doi.org/10.3846/16487788.2012.732323.

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Understanding a definite geographic context is essential for effective air transport management. To date, the consequences of changing weather conditions and climate on the transportation sector in Ghana has been grievous to the economy of the country. Unfortunately, the impact of climate change on the aviation industry has received very little attention in Ghanaian literature. Meanwhile, it is widely known that transport systems on the whole perform poorly under adverse weather and climatic conditions. This paper seeks to reflect a growing orientation in research and philosophy in the field of air transport and severe weather and climatic constraints. Understanding under-lying principles of climatic conditions and weather is essential to air navigation in Ghana. Clear air turbulence, ceiling and visibility, thunderstorms, electrical phenomenon, climate-induced seasonal variations, and vegetation are some of the threats to air transport across Ghana's airspace. Information is derived from literature surveys, workplace counts, and an aviation researcher. Overall, large information technology investments, consolidation, and re-structuring are all major issues that must be addressed by stakeholders ambitious to stay afloat and competitive in Ghana's airspace.

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Brown, Carissa D., et Mark Vellend. « Non-climatic constraints on upper elevational plant range expansion under climate change ». Proceedings of the Royal Society B : Biological Sciences 281, n^o 1794 (7 novembre 2014) : 20141779. http://dx.doi.org/10.1098/rspb.2014.1779.

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We are limited in our ability to predict climate-change-induced range shifts by our inadequate understanding of how non-climatic factors contribute to determining range limits along putatively climatic gradients. Here, we present a unique combination of observations and experiments demonstrating that seed predation and soil properties strongly limit regeneration beyond the upper elevational range limit of sugar maple, a tree species of major economic importance. Most strikingly, regeneration beyond the range limit occurred almost exclusively when seeds were experimentally protected from predators. Regeneration from seed was depressed on soil from beyond the range edge when this soil was transplanted to sites within the range, with indirect evidence suggesting that fungal pathogens play a role. Non-climatic factors are clearly in need of careful attention when attempting to predict the biotic consequences of climate change. At minimum, we can expect non-climatic factors to create substantial time lags between the creation of more favourable climatic conditions and range expansion.

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Kumar, Manoj, S. N. Ojha, Arpita Sharma et Raushan Kumar. « A study on constraints in adoption of scientific aquaculture practices ». Journal of Applied and Natural Science 6, n^o 2 (1 décembre 2014) : 696–700. http://dx.doi.org/10.31018/jans.v6i2.520.

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A study was undertaken to ascertain constraints faced by fish farmers in adoption of scientific aquaculture practices in East Champaran and West Champaran districts of Bihar. Information from 144 respondents was collected and analysed by calculating the Rank Based Quotient (RBQ) values. RBQ value for constraint faced by farmers were extreme climatic conditions (84.03), less extension programs and technical support (78.47), lack of contact with extension personnel’s (71.33), lack of awareness about scientific culture practices (65.28), inadequate credit facility (60.42), labour scarcity (57.64) and higher cost of material input (52.08).These constraints could be categorised under five heads namely extension constraints, financial constraints, production constraints, marketing constraints and social constraints. Average RBQ value for constraints related to extension was found to be 71.76 and ranked first. This was followed by financial constraint with RBQ value of 52.78. Production related constraint ranked third with an average RBQ value of 49.3 followed by marketing (32.87) and social constraints(27.08). Hypothesis that there is no significant difference with reference to rankings of constraints was tested by single factor ANOVA. Null hypothesis was rejected as Ftab=3.48>FNcal=2.61 with df=4 at 5% level of significance. There was a significant difference with reference to rankings of constraints. As the extension related constraints had the highest average RBQ value, it is clear that there is an urgent need of making effective strategy, engaging more fisheries extension professionals in this field along with capacity development of the existing extension professionals.

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Tsai, J. « Climatic Constraints on Rice Production in Taiwan ». Journal of Agricultural Meteorology 52, n^o 5 (1997) : 823–32. http://dx.doi.org/10.2480/agrmet.52.823.

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Laughlin, Daniel C., Peter Z. Fulé, David W. Huffman, Joseph Crouse et Etienne Laliberté. « Climatic constraints on trait-based forest assembly ». Journal of Ecology 99, n^o 6 (8 septembre 2011) : 1489–99. http://dx.doi.org/10.1111/j.1365-2745.2011.01885.x.

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Khan, Naheed Zia, Karamat Ali et John R. Anania. « Productivity Constraints of Cholistani Farmers ». Pakistan Development Review 35, n^o 4II (1 décembre 1996) : 549–63. http://dx.doi.org/10.30541/v35i4iipp.549-563.

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This paper examines the factors behind low crop yield in Cholistan. Both the quantitative and qualitative analysis show how the low levels of agricultural productivity in this area may be linked to material and climatic factors. The quantitative analysis is mainly focused on physical factors. The qualitative analysis, however, emphasises that relative inefficiency of agricultural activity in Cholistan reflects the influence of physical, economic, social and, most importantly, climatic factors. The quantitative findings provide valuable insight into various ‘sources of productivity’ in terms of acreage effect, capital input effect and irrigation water availability effect. The size of the positive and significant coefficients on these variables suggest the extent to which one or the other variable effect is prominent in improving the crop yield. The qualitative analysis examines multiple interrelated factors which can be blamed on for relative inefficiency of Cholistani farmers. The hot climate of the area turns out to be the most critical variable in this analysis. Many specific technological drought-mitigating measures are proposed. However, for consistent policy formulation, a thorough study and quantitative evaluation of the potential and practicality of these measures in Cholistan is suggested.

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Lawson, T. L., et M. V. K. Sivakumar. « Climatic constraints to crop production and fertilizer use ». Fertilizer Research 29, n^o 1 (juillet 1991) : 9–20. http://dx.doi.org/10.1007/bf01048985.

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Mongwe, Precious, Matthew Long, Takamitsu Ito, Curtis Deutsch et Yeray Santana-Falcón. « Climatic controls on metabolic constraints in the ocean ». Biogeosciences 21, n^o 15 (1 août 2024) : 3477–90. http://dx.doi.org/10.5194/bg-21-3477-2024.

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Abstract. Observations and models indicate that climate warming is associated with the loss of dissolved oxygen from the ocean. Dissolved oxygen is a fundamental requirement for heterotrophic marine organisms (except marine mammals) and, since the basal metabolism of ectotherms increases with temperature, warming increases organisms' oxygen demands. Therefore, warming and deoxygenation pose a compound threat to marine ecosystems. In this study, we leverage an ecophysiological framework and a compilation of empirical trait data quantifying the temperature sensitivity and oxygen requirements of metabolic rates for a range of marine species (“ecotypes”). Using the Community Earth System Model Large Ensemble, we investigate how natural climate variability and anthropogenic forcing impact the ability of marine environments to support aerobic metabolisms on interannual to multi-decadal timescales. Warming and deoxygenation projected over the next several decades will yield a reduction in the volume of viable ocean habitats. We find that fluctuations in temperature and oxygen associated with natural variability are distinct from those associated with anthropogenic forcing in the upper ocean. Further, the joint temperature–oxygen anthropogenic signal emerges sooner than temperature and oxygen independently from natural variability. Our results demonstrate that anthropogenic perturbations underway in the ocean will strongly exceed those associated with the natural system; in many regions, organisms will be pushed closer to or beyond their physiological limits, leaving the ecosystem more vulnerable to extreme temperature–oxygen events.

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Menzel, Florian, Bonnie B. Blaimer et Thomas Schmitt. « How do cuticular hydrocarbons evolve ? Physiological constraints and climatic and biotic selection pressures act on a complex functional trait ». Proceedings of the Royal Society B : Biological Sciences 284, n^o 1850 (15 mars 2017) : 20161727. http://dx.doi.org/10.1098/rspb.2016.1727.

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Cuticular hydrocarbons (CHCs) cover the cuticles of virtually all insects, serving as a waterproofing agent and as a communication signal. The causes for the high CHC variation between species, and the factors influencing CHC profiles, are scarcely understood. Here, we compare CHC profiles of ant species from seven biogeographic regions, searching for physiological constraints and for climatic and biotic selection pressures. Molecule length constrained CHC composition: long-chain profiles contained fewer linear alkanes, but more hydrocarbons with disruptive features in the molecule. This is probably owing to selection on the physiology to build a semi-fluid cuticular layer, which is necessary for waterproofing and communication. CHC composition also depended on the precipitation in the ants' habitats. Species from wet climates had more alkenes and fewer dimethyl alkanes than those from drier habitats, which can be explained by different waterproofing capacities of these compounds. By contrast, temperature did not affect CHC composition. Mutualistically associated (parabiotic) species possessed profiles highly distinct from non-associated species. Our study is, to our knowledge, the first to show systematic impacts of physiological, climatic and biotic factors on quantitative CHC composition across a global, multi-species dataset. We demonstrate how they jointly shape CHC profiles, and advance our understanding of the evolution of this complex functional trait in insects.

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S.R, Padma,, Sree Madhumitha et Anupam, H. H. « Suggestions For Overcoming Obstacles In Betelvine Cultivation Of Davanagere District, Karnataka ». Agriculture Association of Textile Chemical and Critical Reviews Journal 12, n^o 3 (12 juin 2023) : 241–44. http://dx.doi.org/10.58321/aatccreview.2023.11.03.241.

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Like every other occupation, agriculture has its own constraints. In such a way, this article portrays the various constraints/ barriers experienced by the Davanagere district betelvine growers involved in betelvine cultivation. Harihara and Honnali taluks of the Davanagere district were purposively selected as it holds the highest area under betelvine cultivation. Twenty-five betelvine growers were selected from each of the six selected villages of two taluks of the Davanagere district of Karnataka. The selected betelvine growers were enquired about the difficulties experienced in betelvine cultivation using a three-point continuum and analyzed using Constraint Faced Index (CFI). Based on the study, it was found that yield loss due to inconsistent climatic conditions, high cost of labour, high cost of chemicals and fluctuation in market price were the prominent technical, labour, economic and marketing constraints experienced by the betelvine growers of Davanagere district respectively. Encouraging value-added products was the highly suggested measure followed by a provision of good quality inputs and providing credit facilities were the key suggestions put forward by the betelvine growers to overcome the constraints.

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Chiarenza, Alfio Alessandro, Philip D. Mannion, Alex Farnsworth, Matthew T. Carrano et Sara Varela. « Climatic constraints on the biogeographic history of Mesozoic dinosaurs ». Current Biology 32, n^o 3 (février 2022) : 570–85. http://dx.doi.org/10.1016/j.cub.2021.11.061.

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Canterbury, Grant. « METABOLIC ADAPTATION AND CLIMATIC CONSTRAINTS ON WINTER BIRD DISTRIBUTION ». Ecology 83, n^o 4 (avril 2002) : 946–57. http://dx.doi.org/10.1890/0012-9658(2002)083[0946:maacco]2.0.co;2.

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Simon, Monique Nouailhetas, Fabio Andrade Machado et Gabriel Marroig. « High evolutionary constraints limited adaptive responses to past climate changes in toad skulls ». Proceedings of the Royal Society B : Biological Sciences 283, n^o 1841 (26 octobre 2016) : 20161783. http://dx.doi.org/10.1098/rspb.2016.1783.

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Interactions among traits that build a complex structure may be represented as genetic covariation and correlation. Genetic correlations may act as constraints, deflecting the evolutionary response from the direction of natural selection. We investigated the relative importance of drift, selection, and constraints in driving skull divergence in a group of related toad species. The distributional range of these species encompasses very distinct habitats with important climatic differences and the species are primarily distinguished by differences in their skulls. Some parts of the toad skull, such as the snout, may have functional relevance in reproductive ecology, detecting water cues. Thus, we hypothesized that the species skull divergence was driven by natural selection associated with climatic variation. However, given that all species present high correlations among skull traits, our second prediction was of high constraints deflecting the response to selection. We first extracted the main morphological direction that is expected to be subjected to selection by using within- and between-species covariance matrices. We then used evolutionary regressions to investigate whether divergence along this direction is explained by climatic variation between species. We also used quantitative genetics models to test for a role of random drift versus natural selection in skull divergence and to reconstruct selection gradients along species phylogeny. Climatic variables explained high proportions of between-species variation in the most selected axis. However, most evolutionary responses were not in the direction of selection, but aligned with the direction of allometric size, the dimension of highest phenotypic variance in the ancestral population. We conclude that toad species have responded to selection related to climate in their skulls, yet high evolutionary constraints dominated species divergence and may limit species responses to future climate change.

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Zha, Xinjie, Ben Niu, Meng Li et Cheng Duan. « Increasing Impact of Precipitation on Alpine-Grassland Productivity over Last Two Decades on the Tibetan Plateau ». Remote Sensing 14, n^o 14 (17 juillet 2022) : 3430. http://dx.doi.org/10.3390/rs14143430.

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Understanding the importance of temperature and precipitation on plant productivity is beneficial, to reveal the potential impact of climate change on vegetation growth. Although some studies have quantified the response of vegetation productivity to climate change at local, regional, and global scales, changes in climatic constraints on vegetation productivity over time are not well understood. This study combines the normalized difference vegetation index (NDVI) and the net primary production (NPP) modeled by CASA during the plant-growing season, to quantify the interplay of climatic (growing-season temperature and precipitation, GST and GSP) constraints on alpine-grassland productivity on the Tibetan Plateau, as well as the temporal dynamics of these constraints. The results showed that (1) 42.2% and 36.3% of grassland NDVI and NPP on the Tibetan Plateau increased significantly from 2000 to 2019. GSP controlled grassland growth in dryland regions, while humid grasslands were controlled by the GST. (2) The response strength of the NDVI and NPP to precipitation (partial correlation coefficient RNDVI-GSP and RNPP-GSP) increased substantially between 2000 and 2019. Especially, the RNDVI-GSP and RNPP-GSP increased from 0.14 and 0.01 in the first 10year period (2000–2009) to 0.83 and 0.78 in the second 10-year period (2010–2019), respectively. As a result, the controlling factor for alpine-grassland productivity variations shifted from temperature during 2000–2009 to precipitation during 2010–2019. (3) The increase in precipitation constraints was mainly distributed in dryland regions of the plateau. This study highlights that the climatic constraints on alpine-grassland productivity might change under ongoing climate change, which helps the understanding of the ecological responses and helps predict how vegetation productivity changes in the future.

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Normand, Signe, Christophe Randin, Ralf Ohlemüller, Christian Bay, Toke T. Høye, Erik D. Kjær, Christian Körner et al. « A greener Greenland ? Climatic potential and long-term constraints on future expansions of trees and shrubs ». Philosophical Transactions of the Royal Society B : Biological Sciences 368, n^o 1624 (19 août 2013) : 20120479. http://dx.doi.org/10.1098/rstb.2012.0479.

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Warming-induced expansion of trees and shrubs into tundra vegetation will strongly impact Arctic ecosystems. Today, a small subset of the boreal woody flora found during certain Plio-Pleistocene warm periods inhabits Greenland. Whether the twenty-first century warming will induce a re-colonization of a rich woody flora depends on the roles of climate and migration limitations in shaping species ranges. Using potential treeline and climatic niche modelling, we project shifts in areas climatically suitable for tree growth and 56 Greenlandic, North American and European tree and shrub species from the Last Glacial Maximum through the present and into the future. In combination with observed tree plantings, our modelling highlights that a majority of the non-native species find climatically suitable conditions in certain parts of Greenland today, even in areas harbouring no native trees. Analyses of analogous climates indicate that these conditions are widespread outside Greenland, thus increasing the likelihood of woody invasions. Nonetheless, we find a substantial migration lag for Greenland's current and future woody flora. In conclusion, the projected climatic scope for future expansions is strongly limited by dispersal, soil development and other disequilibrium dynamics, with plantings and unintentional seed dispersal by humans having potentially large impacts on spread rates.

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Bhuyan, Pradip C., Chandan Goswami, Bipul Kr Kakati et Kaustubh Bhagawati. « Constraints in adoption of composite carp culture in central Brahmaputra valley zone of Assam - a perceptual framework ». Journal of Applied and Natural Science 9, n^o 2 (1 juin 2017) : 730–35. http://dx.doi.org/10.31018/jans.v9i2.1265.

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The study was conducted in Nagaon district under central Brahmaputra valley zone of Assam to find out the perceptual constraints of the fish farmers in adoption of composite carp culture practice. A representative sample of 60 fish farmers of the district was selected using random sampling. The levels of agreement of respondents in relation to 32 identified constraints in adoption of composite fish culture were determined using 5 point Likert scale. The mean value of degree of responsiveness to constraints was analyzed to find out the perception of the farmers and found lack of fish feed at cheaper rate (3.45) as major constraint followed by high initial cost of digging of ponds (3.28). Seven factors of constraints have been identified through factor analysis such as extension support system constraints, knowledge constraints, financial constraints,distribution constraints, infrastructural constraints, agro-climatic constraints and situational constraints. With the constraints as perceived by the farmers, some relevant strategies have been suggested such as integrated effort to provide better quality fish seed at proper time at pond site of farmers through judicious carp breeding and hatchery management and proper distribution system; strengthening research extension linkage; organizing need based short and long-term training programme and on farm demonstration programme on various aspects of fish culture practices both for farmers and extension workers; establishment of ‘One stop Aqua Shop’(OAS) as single outlet in strategic locations to make available all inputs required for fish culture; formation of fish producer’s consortium to provide a dependable market support and a suitable delivery system for providing inputs to the fish farmers in time and better provision of institutional credit.

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Skandalis, Dimitri A., Miriam H. Richards, Todd S. Sformo et Glenn J. Tattersall. « Climate limitations on the distribution and phenology of a large carpenter bee, Xylocopa virginica (Hymenoptera : Apidae) ». Canadian Journal of Zoology 89, n^o 9 (septembre 2011) : 785–95. http://dx.doi.org/10.1139/z11-051.

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We studied climatic correlates of the geographic range of a common large carpenter bee ( Xylocopa virginica (L., 1771)), which reaches farther north than any other Xylocopa in North America. Computational models of the species’ range predicted that summer and winter temperatures limit its northern extent, whereas summer precipitation limits its western extent. We empirically evaluated the climatic constraints imposed by different seasons by examining the winter low-temperature tolerance of X. virginica, and the timing of activity during spring and summer. The bee’s absolute low-temperature tolerance (supercooling point) did not differ between two populations at mid- and high latitudes, and was in excess of requirements of a mean winter minimum temperature. Absolute minimum temperature tolerances may not directly influence the range of X. virginica, whereas other measures of cold tolerance, like exposure duration, might be more relevant. Between years within a study population, spring emergence dates of bees were significantly predicted by spring temperatures and weather (April: 6–11 °C; May: 13–17 °C). Between populations across the bee’s geographic range, bees in warmer climates were observed as much as 2–3 months earlier in the year. This suggests that a major constraint on the bee’s range is the length of the active season, which may be too short for brood development at high latitudes.

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Ma, Yu-Jun, Fang-Zhong Shi, Xia Hu et Xiao-Yan Li. « Climatic Constraints to Monthly Vegetation Dynamics in Desert Areas Over the Silk Road Economic Belt ». Remote Sensing 13, n^o 5 (5 mars 2021) : 995. http://dx.doi.org/10.3390/rs13050995.

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The sustainability of vulnerable eco-environment over the Silk Road Economic Belt is under threat of climate change, and the identification of vegetation constraints by sub-optimum climatic conditions is critically essential to maintain existing dryland ecosystems. To better understand how the vegetation varies at monthly scale and its effect by climate conditions in different desert areas, this study first investigated the seasonal variation of the normalized difference vegetation index (NDVI). Then, we analyzed the time effects of diverse climatic factors (air temperature, solar radiation, precipitation) on NDVI and estimated the limitation of NDVI by these climatic factors in different desert areas. The result showed that the mean monthly NDVI during 1982–2015 showed a unimodal variation in most desert areas, with high values in late spring and summer over cold arid areas, in early spring or early autumn over hot arid areas, and in summer over polar areas, respectively. Solar radiation and precipitation in cold arid areas presented 1–2 month lag or accumulation effect on NDVI, while precipitation in most hot arid areas showed no remarkable time-lag but 3 month accumulation effect, and all three climate factors in polar areas exhibited 1–3 month accumulation effect. The explanatory power of climatic conditions for vegetation dynamics considering time effects increased by 3.4, 10.8, and 5.9% for the cold arid areas, hot arid areas, and polar areas (i.e., relative increase of 4.1, 25.4, and 8.2%), respectively. The main climatic constraints to vegetation dynamics were the water condition in hot arid areas (>78%) and the temperature condition in polar areas (>67%), while cold arid areas were simultaneously limited by the water and temperature conditions (>76% in total). These results provide a detailed understanding of vegetation variation and ecological projection, which are very important to implement adaption measures for dryland ecosystems over the Silk Road Economic Belt.

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Owen, J. E. « Advances in climatic control ». BSAP Occasional Publication 11 (janvier 1987) : 87–92. http://dx.doi.org/10.1017/s0263967x00001804.

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AbstractElectronic control systems offer a big potential for improved environmental control inpig buildings. Their use is however limited to those types of controllers that can replicate the features of older electromechanical controls. Current research and development work, which is not confined to pig building applications, is largely concerned with extending the use of microprocessor-based controllers to incorporate features such as: (a) control based on parameters other than simply air temperature; (b) control based on algorithmswhich predict the pigs’ needs; and (c) control which integrates alarm, fail safe and monitoring.To accommodate these features more advanced controllers are used, however their use in practice is likely to be limited by a number of technical, economic and ergonomie constraints.

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MALIK, M. H., et H. K. VERMA. « Epidemiological aspect and major constraints in controlling haemorrhagic septicemia in dairy animals of Punjab ». Indian Journal of Animal Sciences 88, n^o 10 (22 octobre 2018) : 1112–17. http://dx.doi.org/10.56093/ijans.v88i10.84069.

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Present study was undertaken to study the epidemiological aspect of haemorrhagic septicemia (HS) in dairy animals and various constraints in controlling its occurrence in different agro-climatic zones of Punjab. The study was conducted in all the different agro-climatic zones of Punjab by multistage stratified random sampling of 720 dairy farmers and categorized them on the basis of herd size of dairy animals, viz. small (5–10), medium (11–50) and large (>50). The overall incidence and case fatality rate (CFR) of HS among dairy animals was 5.45 and 45.15% respectively. Incidence risk of HS on the species basis varied significantly and was observed highest in buffaloes (6.27%), followed by crossbred (4.67%) and indigenous cattle (3.91%). Within different herd sizes, the incidence risk of HS varied significantly and was highest in small herd size (10.52%) followed by medium (5.44%) and large herd size (3.01%). Incidence risk varied significantly between the different agro-climatic zones of Punjab within small and large sized herds but not in medium sized herds. CFR among the different herds was highest in small herd (49.28%) followed by medium herd (44.32%) and large herd (39.15%). The major constraints faced by farmers for controlling HS estimated by using Garrett’s ranking technique included failure of prophylactic vaccination, cost of treatment, strict biosafety measures and hygienic sanitary conditions not followed, inadequate early disease detection and poor availability of veterinary and extension services. Various veterinary and extension tools should be chosen based on agro-climatic conditions and analyzing farmers in respect of education, herd size, extension contacts, teledensity and training etc. to overcome this dreadful disease of dairy animals.

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Studds, Colin E., et Peter P. Marra. « Rainfall-induced changes in food availability modify the spring departure programme of a migratory bird ». Proceedings of the Royal Society B : Biological Sciences 278, n^o 1723 (30 mars 2011) : 3437–43. http://dx.doi.org/10.1098/rspb.2011.0332.

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Climatic warming has intensified selection for earlier reproduction in many organisms, but potential constraints imposed by climate change outside the breeding period have received little attention. Migratory birds provide an ideal model for exploring such constraints because they face warming temperatures on temperate breeding grounds and declining rainfall on many tropical non-breeding areas. Here, we use longitudinal data on spring departure dates of American redstarts ( Setophaga ruticilla ) to show that annual variation in tropical rainfall and food resources are associated with marked change in the timing of spring departure of the same individuals among years. This finding challenges the idea that photoperiod alone regulates the onset of migration, providing evidence that intensifying drought in the tropical winter could hinder adaptive responses to climatic warming in the temperate zone.

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Evans, D. A. D. « Stratigraphic, geochronological, and paleomagnetic constraints upon the Neoproterozoic climatic paradox ». American Journal of Science 300, n^o 5 (1 mai 2000) : 347–433. http://dx.doi.org/10.2475/ajs.300.5.347.

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Garonna, Irene, Rogier de Jong, Reto Stöckli, Bernhard Schmid, David Schenkel, David Schimel et Michael E. Schaepman. « Shifting relative importance of climatic constraints on land surface phenology ». Environmental Research Letters 13, n^o 2 (1 février 2018) : 024025. http://dx.doi.org/10.1088/1748-9326/aaa17b.

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Dennis, R. L. H., et T. G. Shreeve. « Climatic change and the British butterfly fauna : Opportunities and constraints ». Biological Conservation 55, n^o 1 (1991) : 1–16. http://dx.doi.org/10.1016/0006-3207(91)90002-q.

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Oyim, Abigail, Kelechi Kenneth Osayi, Chika Maureen Okaforocha et Ebele Stella Nwokoye. « Constraints to Agricultural Productivity in South East Nigeria : Evidence from Small-Scale Farmers in Abakaliki Metropolis ». International Journal of Research and Innovation in Social Science VII, n^o X (2023) : 1586–600. http://dx.doi.org/10.47772/ijriss.2023.701122.

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Being a key component of Ebonyi State economy, revenue from its agricultural sector has been on the decline. Literature search show that issues of constraints to agricultural productivity in the State have not been sufficiently classified. This study fills this gap by ascertaining the impact of economic, social and environmental factors on agricultural productivity in Abakaliki metropolis. Based on structural change theory, primary data were generated with the aid of a well-structured questionnaire. Simple random sampling technique was used to select 20 villages while purposive sampling technique was applied in selecting 10 farmers making it a total of 200 participants. Three null hypotheses were tested using F-test from analysis of variance (ANOVA) and Welch tests. We found that economic, social and environmental factors significantly constrained agricultural productivity in Abakaliki Metropolis. We also found evidences that high cost of mechanised farming relative to manual labour and inadequate capital; land constraint and low level of education of farmers; as well as problem of pest and diseases and climatic changes were, respectively, two major economic, socio-economic and environmental constraints to agricultural productivity. This study therefore recommends government intervention in the area of irrigation, drought-resistant technologies, and floods controls as necessary tools for climate change adaptation as well as improved farm tools, pest control, and access to farm lands.

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MacEwan, R. J., D. M. Crawford, P. J. Newton et T. S. Clune. « High clay contents, dense soils, and spatial variability are the principal subsoil constraints to cropping the higher rainfall land in south-eastern Australia ». Soil Research 48, n^o 2 (2010) : 150. http://dx.doi.org/10.1071/sr09076.

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Available soil information and unpublished data from soil survey indicate that high clay contents and high bulk density are the major subsoil constraints to crop growth in the high rainfall zone (HRZ) of south-eastern Australia. Seven high rainfall agroecological zones are proposed as sub-divisions of the region to focus future research and development. The HRZ is dominated by texture-contrast soils (69.9%) and soils with clay subsoil (89.4%) and high bulk density (mean 1.6 t/m3). Sodicity and acidity are also significant constraints to crop production in the HRZ. The physical limitations to root growth in the HRZ subsoils are best appreciated through the least-limiting water range concept and growth-limiting bulk densities. Management options and results of past research and intervention in soil loosening, drainage, raised beds, liming, and gypsum are reviewed. Climatic uncertainty raises questions about the future relevance of waterlogging as a constraint in the HRZ and confounds the development of reliable recommendations for engineering intervention.

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Russell, Vanessa L., M. Henry H. Stevens, Addison A. Zeisler et Tereza Jezkova. « Identifying regional environmental factors driving differences in climatic niche overlap in Peromyscus mice ». Journal of Mammalogy 103, n^o 1 (2 décembre 2021) : 45–56. http://dx.doi.org/10.1093/jmammal/gyab126.

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Abstract Different groups of taxa exhibit varying degree of climatic niche conservatism or divergence due to evolutionary constraints imposed on taxa and distributional relationships among them. Herein, we explore to what extent regional environmental conditions that taxa occupy affect climatic niche overlap between pairs of congeneric species of Peromyscus mice exhibiting allopatric, parapatric, or sympatric distributions. We used Bayesian generalized linear mixed models to identify environmental variables that best explain differences in climatic niche overlap between species. Our results suggest that regional environmental conditions explain 13–44% of variation in climatic niche overlap. Specifically, allopatric and parapatric species pairs are more likely to occupy similar climatic niches in areas that are topographically less complex but with more complex habitats. Sympatric species are more likely to occupy similar climatic niches in areas that promote local niche partitioning (topographically less complex, warmer winter temperatures, higher precipitation, and higher habitat complexity on a local scale). By understanding the relationship between regional environmental conditions and niche overlap, we highlight how differences in geography can contribute to shaping niches of congeneric species.

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Van de Perre, Frederik, Michael R. Willig, Steven J. Presley, Itoka Jean-Claude Mukinzi, Mbalitini Sylvestre Gambalemoke, Herwig Leirs et Erik Verheyen. « Functional volumes, niche packing and species richness : biogeographic legacies in the Congo Basin ». Royal Society Open Science 7, n^o 3 (mars 2020) : 191582. http://dx.doi.org/10.1098/rsos.191582.

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Understanding the determinants of species coexistence in complex and species-rich communities is a fundamental goal of ecology. Patterns of species coexistence depend on how biotic interactions and environmental filtering act over ecological and evolutionary time scales. Climatic fluctuations in lowland rainforests of the Congo Basin led to the number of vertebrate species being significantly lower in central compared with northern ecoregions of the Basin. We used null models to assess whether climatic variations affected the community assembly of shrews. A consistent limit to functional similarity of species was not related to species richness. Rather, species richness is constrained by environmental factors, and these constraints are stronger in the central lowland forests of the Congo Basin. By constraining species geographic distributions, historical effects of rainforest refugia arising from climatic fluctuations may affect contemporary species composition of local shrew communities. The Congo River represents a vicariance event that led to allopatric speciation of shrews and continues to represent a barrier to dispersal. Ultimately, the historical effects of this barrier have led to differences in the functional volume of shrew communities in northern and central ecoregions. We suggest that the analyses of community assembly can be used to identify Holocene refugia in the Congo Basin.

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WALKER, S. M., A. E. MAKUNDI, F. V. NAMUBA, A. A. KASSUKU, J. KEYYU, E. M. HOEY, P. PRÖDOHL, J. R. STOTHARD et A. TRUDGETT. « The distribution ofFasciola hepaticaandFasciola giganticawithin southern Tanzania – constraints associated with the intermediate host ». Parasitology 135, n^o 4 (21 janvier 2008) : 495–503. http://dx.doi.org/10.1017/s0031182007004076.

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SUMMARYIn East Africa,Fasciola giganticais generally the causative agent of fasciolosis but there have been reports ofF. hepaticain cattle from highland regions of Kenya, Ethiopia, Uganda and Zaire. The topography of the Southern Highlands of Tanzania provides an environment where the climatic conditions exist for the sustenance of lymnaeid species capable of supporting bothFasciola hepaticaandF. gigantica. Theoretically this would allow interaction between fasciolid species and the possible creation of hybrids. In this report we present molecular data confirming the existence of the snail,Lymnaea truncatula, at high altitude on the Kitulo Plateau of the Southern Highlands, Tanzania, along with morphometric and molecular data confirming the presence ofF. hepaticain the corresponding area. At lower altitudes, where climatic conditions were unfavourable for the existence ofL. truncatula, the presence of its sister speciesL. natalensiswas confirmed by molecular data along with its preferred fasciolid parasite,F. gigantica. Analysis based on a 618 bp sequence of the 28S rRNA gene did not reveal the presence of hybrid fasciolids in our fluke samples.

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Kim, Yean‐Uk, Kanghyun Moon et Byun‐Woo Lee. « Climatic constraints to yield and yield components of temperate japonica rice ». Agronomy Journal 113, n^o 4 (20 juin 2021) : 3489–97. http://dx.doi.org/10.1002/agj2.20689.

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Kearney, Michael R. « Prizing open a black box to understand climatic constraints on seabirds ». Journal of Biogeography 38, n^o 3 (3 février 2011) : 417–18. http://dx.doi.org/10.1111/j.1365-2699.2010.02459.x.

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Batungwanayo, Pacifique, Marnik Vanclooster et Alan F. Koropitan. « Response of Seasonal Vegetation Dynamics to Climatic Constraints in Northeastern Burundi ». Journal of Geoscience and Environment Protection 08, n^o 09 (2020) : 151–81. http://dx.doi.org/10.4236/gep.2020.89010.

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Kaspersen, Per Skougaard, Rasmus Fensholt et Silvia Huber. « A Spatiotemporal Analysis of Climatic Drivers for Observed Changes in Sahelian Vegetation Productivity (1982–2007) ». International Journal of Geophysics 2011 (2011) : 1–14. http://dx.doi.org/10.1155/2011/715321.

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Linear trend analysis and seasonal trend analysis are performed on gridded data of vegetation, rainfall, solar radiation flux, and air temperature, in order to examine the influence of the past three decades of climate variability and change on the Sahelian vegetation dynamics. Per-pixel correlation analyses are conducted on annual and monthly data, and analyses of change in the potential climatic constraints to the natural vegetation development from 1982–2007 are performed. The results reveal two distinct periods: (a) 1982–1994 marked by large increases in vegetation productivity and rainfall and little change in average air temperatures and solar radiation and (b) 1995–2007 characterized by no distinct trends in vegetation productivity and rainfall and increase in average air temperatures and decrease in solar radiation flux. Correlations between vegetation productivity and climatic constraints were found to be statistically significant only for rainfall explaining only a moderate degree of observed NDVI variation, indicating that nonclimatic factors are also important for the Sahelian vegetation dynamics.

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Kumar, Pawan, P. S. Shehrawat, Anil Kumar Rohila, B. S. Ghanghas et Ashok Kumar. « Constraints faced by farmers of Haryana state in adoption of masumbi (Citrus sinensis) cultivation ». Journal of Applied and Natural Science 8, n^o 2 (1 juin 2016) : 785–89. http://dx.doi.org/10.31018/jans.v8i2.874.

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The study focused on the constraints faced by farmers of Haryana state in adoption of masumbi (Citrus sinensis) cultivation. The study was conducted in Bhiwani district. The constraints as perceived by the respondents were measured by the scores on the basis of magnitude of the problems. Constraints were categorized into inputs, marketing, production, technical and psychologicalconstraints. While analyzing overall constraints as perceived by farmers the findings revealed that high price of insecticides/pesticides (weighted mean score 2.25), non-availability of inputs at proper time (1.13), absence of agro-processing units (2.05), no support price (1.86), aberrant climatic conditions (1.99), unawareness about proper and balanced fertilizer application and time of application (1.99), lack of guidance of post-harvest technology (1.95), lack of knowledge of current advances in fruit cultivation (1.34), longer time taken in fruit bearing (1.51) and orchard maintenance(1.34) etc. were major constraints faced by the farmers.

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Lee, Hyejin. « The Current Status and Constraints of Drought-Tolerant Maize Adoption in Uganda ». Open Agriculture Journal 14, n^o 1 (30 juillet 2020) : 98–107. http://dx.doi.org/10.2174/1874331502014010098.

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Agriculture is an economic backbone of many sub-Saharan African countries, including Uganda. However, the country is grappling with slow agricultural development and food insecurity. Concurrently, Uganda faces climatic challenges that likely become further constraints for agricultural production. Maize is one of its major crops and serves as a food and cash crop for smallholders. However, its productivity remains low. To improve maize productivity under increasing temperatures and droughts, drought-tolerant maize (DTM) has been released, but it is not widely adopted. The objective of this study is, therefore, to review the current situation of DTM adoption in Uganda and identify characteristic differences between adopters and non-adopters and possible constraints for wider adoption. In doing so, available literature, policy documents and relevant reports on the subject were reviewed. The systemic approach was not feasible due to limited availability of reliable sources. Drought-tolerant maize adopters in Uganda appeared to be better endowed with production resources such as larger farmland, be more informed, educated and experienced, have a larger household, use more inputs more efficiently, earn higher income and harvest better yield. Major constraints to DTM adoption included lack of awareness, limited seed availability and accessibility, complementary input requirement, existing DTM attributes and dubious market quality of seed and fertilizer. These constraints and adoption characteristics seemed intertwined as a virtuous or vicious cycle for DTM adoption. Although a broad range of DTM adoption constraints is identified at a household, market and national level, DTM can be an effective means to improve maize productivity under climatic challenges in Uganda. To promote its adoption, the government should take more supportive measures and effective strategies for sustainable DTM uptake.

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Agarwal, Disha, P. K. Chahal, B. S. Ghanghas et Shubham. « Analysis of Constraints Faced by Sugarcane Growers in Haryana, India ». Asian Journal of Agricultural Extension, Economics & ; Sociology 42, n^o 5 (6 mai 2024) : 443–48. http://dx.doi.org/10.9734/ajaees/2024/v42i52456.

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Sugarcane is one of the most important cash crop globally. In Haryana, particularly in the districts of Yamuna Nagar, Kaithal, and Rohtak, sugarcane production is significant. However, the adoption of production technology among sugarcane growers in these areas faces various constraints, impacting productivity and profitability. This study aims to identify the constraints faced by sugarcane growers in adopting production technology in Haryana. In order to gather information about the difficulties sugarcane growers had in implementing the production technique, structured interviews were conducted in 2023. The findings indicate that a majority of sugarcane growers (56.70%) experienced medium constraints, while 22.50% and 20.80% faced high and low constraints, respectively. Key constraints identified include high labor charges during harvesting, elevated transportation costs, labor shortages during peak periods, variability in agro-climatic conditions, and high prices of plant protection chemicals. The findings underscore the need for targeted interventions, such as awareness campaigns, improved supply chains, affordability of inputs, and pest management strategies, to enhance sugarcane production in Haryana.

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Reu, B., S. Zaehle, R. Proulx, K. Bohn, A. Kleidon, R. Pavlick et S. Schmidtlein. « The role of plant functional trade-offs for biodiversity changes and biome shifts under scenarios of global climatic change ». Biogeosciences 8, n^o 5 (24 mai 2011) : 1255–66. http://dx.doi.org/10.5194/bg-8-1255-2011.

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Abstract. The global geographic distribution of biodiversity and biomes is determined by species-specific physiological tolerances to climatic constraints. Current vegetation models employ empirical bioclimatic relationships to predict present-day vegetation patterns and to forecast biodiversity changes and biome shifts under climatic change. In this paper, we consider trade-offs in plant functioning and their responses under climatic changes to forecast and explain changes in plant functional richness and shifts in biome geographic distributions. The Jena Diversity model (JeDi) simulates plant survival according to essential plant functional trade-offs, including ecophysiological processes such as water uptake, photosynthesis, allocation, reproduction and phenology. We use JeDi to quantify changes in plant functional richness and biome shifts between present-day and a range of possible future climates from two SRES emission scenarios (A2 and B1) and seven global climate models using metrics of plant functional richness and functional identity. Our results show (i) a significant loss of plant functional richness in the tropics, (ii) an increase in plant functional richness at mid and high latitudes, and (iii) a pole-ward shift of biomes. While these results are consistent with the findings of empirical approaches, we are able to explain them in terms of the plant functional trade-offs involved in the allocation, metabolic and reproduction strategies of plants. We conclude that general aspects of plant physiological tolerances can be derived from functional trade-offs, which may provide a useful process- and trait-based alternative to bioclimatic relationships. Such a mechanistic approach may be particularly relevant when addressing vegetation responses to climatic changes that encounter novel combinations of climate parameters that do not exist under contemporary climate.

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Kromer, Bernd, et Bernd Becker. « Tree-rings, absolute chronology and climatic change ». European Review 3, n^o 4 (octobre 1995) : 303–8. http://dx.doi.org/10.1017/s1062798700001629.

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In the Hohenheim tree-ring laboratory, two long tree-ring chronologies have been built, spanning the past 11 600 years. This is the world's longest continuous tree-ring calendar. It has become the backbone of the calibration of the radiocarbon time scale, offering absolute and accurate dates for archaeology, vegetation history and paleoclimate studies. 14C analyses of the tree-ring chronologies provide insight into the process controlling the production of cosmogenic nuclides, i.e. mainly the geomagnetic dipole moment and solar variability. They also set geochemical constraints to variations in the carbon cycle during a major climatic excursion.

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Khushbu, Kanta Sabharwal, Jyoti et Santosh Sharma. « Challenges Faced by Farmers in Integrated Farming Systems : Personal and Social Constraints ». Archives of Current Research International 24, n^o 9 (13 septembre 2024) : 119–26. http://dx.doi.org/10.9734/acri/2024/v24i9874.

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India's agricultural sector is dominated by small and marginal farmers with less than two hectares of land, making it difficult to achieve livelihood security and sustainability through single-enterprise farming. With the average size of landholdings shrinking to 1.08 hectares, there is a growing need to adopt Integrated Farming Systems (IFS), which integrate crop and livestock production to enhance sustainability, productivity, and profitability through resource recycling. This study aimed to examine the personal and social constraints faced by farmers practicing IFS in Haryana, India. Conducted as a cross-sectional study over one year in four districts representing the Eastern and Western agro-climatic zones of Haryana, a total of 120 IFS farmers were selected through purposive and random sampling. Data were gathered through structured interviews based on a well-validated questionnaire, with constraints categorized into personal and social dimensions and analyzed using frequency distributions and weighted mean scores (WMS). The results showed that the most severe personal constraint in the Western zone was the lack of knowledge about the balanced use of pesticides and fertilizers (WMS = 2.2), while the Eastern zone's primary personal constraint was a lack of knowledge about different IFS components (WMS = 2.51). In terms of social constraints, Western zone farmers identified a lack of leisure time for family as the most significant issue (WMS = 2.48), while Eastern zone farmers cited inadequate family support as their main constraint (WMS = 2.5). These findings highlight the need for targeted interventions, including knowledge dissemination on IFS components and balanced input usage, as well as improved social support systems to boost the adoption and effectiveness of IFS. The study’s outcomes align with previous research on agricultural challenges and offer actionable recommendations for enhancing IFS practices in Haryana.

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Koumassi, Dègla Hervé. « Facteurs Explicatifs Du Tarissement Des Points D’eau En Milieu De Socle Cristallin Dans Le Departement Des Collines Au Benin ». European Scientific Journal, ESJ 13, n^o 20 (31 juillet 2017) : 206. http://dx.doi.org/10.19044/esj.2017.v13n20p206.

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The department of the hills is located at the center of Benin in plinth area. The water supply in this area is more and more directed towards surface water due to the hydrogeologic constraints and the impact of the climatic fluctuations. The climatological and geological data analysis made by the methods of descriptive statistical analysis made it possible to analyze the dynamics of the climatic parameters on the one hand and the behavior of the geological units to the recorded flows. The hydroclimatic study showed a deficit on the level of the climatic assessment and a decline of pluviometry since 1970. The study of the hydrogeologic characteristics carried out on 706 drillings made it possible to show the relationship between various parameters such as: thickness of change, flows end of boring and productivity of the drilling / lithology.

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Camarero, J. Julio, Raúl Sánchez-Salguero, Montserrat Ribas, Ramzi Touchan, Laia Andreu-Hayles, Isabel Dorado-Liñán, David M. Meko et Emilia Gutiérrez. « Biogeographic, Atmospheric, and Climatic Factors Influencing Tree Growth in Mediterranean Aleppo Pine Forests ». Forests 11, n^o 7 (6 juillet 2020) : 736. http://dx.doi.org/10.3390/f11070736.

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There is a lack of knowledge on how tree species respond to climatic constraints like water shortages and related atmospheric patterns across broad spatial and temporal scales. These assessments are needed to project which populations will better tolerate or respond to global warming across the tree species distribution range. Warmer and drier conditions have been forecasted for the Mediterranean Basin, where Aleppo pine (Pinus halepensis Mill.) is the most widely distributed conifer in dry sites. This species shows plastic growth responses to climate, being particularly sensitive to drought. We evaluated how 32 Aleppo pine forests responded to climate during the second half of the 20th century by using dendrochronology. Climatic constraints of radial growth were inferred by fitting the Vaganov–Shashkin (VS-Lite) growth model to ring-width data from our Aleppo pine forest network. Our findings reported that Aleppo pine growth decreased and showed the highest common coherence among trees in dry, continental sites located in southeastern and eastern inland Spain and Algeria. In contrast, growth increased in wetter sites located in northeastern Spain. Overall, across the Aleppo pine network tree growth was enhanced by prior wet winters and cool and wet springs, whilst warm summers were associated with less growth. The relationships between site ring-width chronologies were higher in nearby forests. This explains why Aleppo pine growth was distinctly linked to indices of atmospheric circulation patterns depending on the geographical location of the forests. The western forests were more influenced by moisture and temperature conditions driven by the Western Mediterranean Oscillation (WeMO) and the Northern Atlantic Oscillation (NAO), the southern forests by the East Atlantic (EA) and the august NAO, while the Balearic, Tunisian and northeastern sites by the Arctic Oscillation (AO) and the Scandinavian pattern (SCA). The climatic constraints for Aleppo pine tree growth and its biogeographical variability were well captured by the VS-Lite model. The model performed better in dry and continental sites, showing strong growth coherence between trees and climatic limitations of growth. Further research using similar broad-scale approaches to climate–growth relationships in drought-prone regions deserves more attention.

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Reu, B., S. Zaehle, R. Proulx, K. Bohn, A. Kleidon, R. Pavlick et S. Schmidtlein. « The role of plant functional trade-offs for biodiversity changes and biome shifts under scenarios of global climatic change ». Biogeosciences Discussions 7, n^o 5 (13 octobre 2010) : 7449–73. http://dx.doi.org/10.5194/bgd-7-7449-2010.

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Abstract. The global geographic distribution of biodiversity and biomes is determined by species-specific physiological tolerances to climatic constraints. Current models implement empirical bioclimatic relationships to predict present-day vegetation patterns and to forecast biodiversity changes and biome shifts under climatic change. In this paper, we consider plant functional trade-offs and their interactions with climatic changes to forecast and explain biodiversity changes and biome shifts. The Jena Diversity model (JeDi) simulates plant survival according to essential plant functional trade-offs, including eco-physiological processes such as water uptake, photosynthesis, allocation, reproduction and phenology. We apply JeDi to quantify biodiversity changes and biome shifts between present-day and a range of possible future climates from two scenarios (A2 and B1) and seven global climate models using metrics of plant functional richness and functional identity. Our results show (i) a significant biodiversity loss in the tropics, (ii) an increase in biodiversity at mid and high latitudes, and (iii) a poleward shift of biomes. While these results are consistent with the findings of empirical approaches, we are able to explain them in terms of the plant functional trade-offs involved in the allocation, metabolic and reproduction strategies of plants. We conclude that general aspects of plant physiological tolerances can be derived from plant functional trade-offs, which may provide a useful process- and trait-based alternative to bioclimatic relationships in order to address questions about the causes of biodiversity changes and biome shifts.

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Sanou, Korotimi, et Jean-Marie Dipama. « Constraints and Prospects of rice Production in a Climate Change Context in the Sissili Province, Burkina Faso ». European Scientific Journal, ESJ 18, n^o 23 (31 juillet 2022) : 140. http://dx.doi.org/10.19044/esj.2022.v18n23p140.

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In terms of irrigated agricultural production in Burkina Faso, rice is the second most important crop after maize. This rice production is supposed to satisfy domestic demand and reduce imports, which has an impact on the country's trade balance. However, the rice sector is faced with climatic and technical productivity constraints. Indeed, the variability of temperatures and rainfall over the period 1988-2018, with its corollaries of drought and flooding episodes, has an impact on agricultural activity. The objective of this study is to analyze the effect of the dynamics of climatic parameters as well as the effectiveness of technological packages on rice productivity in Sissili Province. To this end, a methodology based on the quantitative approach was adopted. It is based on the collection, processing, and analysis of numerical data on key climatic parameters from the Pô synoptic station from 1988 to 2018. These data were correlated with those available on rice production over the same period. The analyses show that Sissili Province is marked by alternating rainfall deficits and surpluses, which have an impact on rice production, the evolution of which is out of phase with the increase in planted areas. This suggests that increasing the area planted seems to be an alternative way of compensating for a possible drop in rainfall. Under these conditions, the development of lowlands and water reservoirs represents opportunities for the diversification of production systems.

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Prashanth, K., et S. S. Nagamuthu Krishnan. « Study of Denial of Service (DoS) Attack in Wireless Sensor Networks with Power Constraints ». International Journal of Innovative Technology and Exploring Engineering 10, n^o 4 (28 février 2021) : 168–71. http://dx.doi.org/10.35940/ijitee.d8482.0210421.

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Wireless sensor networks (WSN) are highly vulnerable to attacks and constraints on resources like power, processing, and radio signal. In high constraint and vulnerable environments adapting to detection and defence mechanisms is a challenge. In this paper analysis of Distributed Denial of Service detection mechanisms of Sybil, Sinkhole, and Wormhole attack for power optimization is carried out based on the power consumption parameter. Power consumption attributes affects the efficiency of nodes during the time of attacks. Energy utilization and conservation also depend upon certain parameters comprising usage of network, changes in topology, climatic changes, no of sensors connected, memory utilization on sensors, and security issues. The analysis takes various attacks detection mechanisms into consideration and a comparative study is projected upon power optimization parameters. This study could contribute to the aspect of extending the activity of the sensor in various applications such as whether monitoring and recording of wildlife movement.

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Sardà-Palomera, Francesc, et David R. Vieites. « Modelling Species' Climatic Distributions Under Habitat Constraints : A Case Study withCoturnix coturnix ». Annales Zoologici Fennici 48, n^o 3 (juin 2011) : 147–60. http://dx.doi.org/10.5735/086.048.0303.

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Thirumavalavan, R., T. Senthil Kumar, N. K. Sudeepkumar, M. Prabhu, Thanga Thamilvanan et P. Venkatesan. « Constraints in buffalo farming in selected agro-climatic zones of Tamil Nadu ». Indian Journal of Extension Education 56, n^o 4 (2020) : 140–43. http://dx.doi.org/10.5958/2454-552x.2020.00065.1.

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Zuckerberg, Benjamin, David N. Bonter, Wesley M. Hochachka, Walter D. Koenig, Arthur T. DeGaetano et Janis L. Dickinson. « Climatic constraints on wintering bird distributions are modified by urbanization and weather ». Journal of Animal Ecology 80, n^o 2 (30 novembre 2010) : 403–13. http://dx.doi.org/10.1111/j.1365-2656.2010.01780.x.

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Amat, Fèlix, et Shai Meiri. « Geographical, climatic and biological constraints on age at sexual maturity in amphibians ». Biological Journal of the Linnean Society 123, n^o 1 (21 décembre 2017) : 34–42. http://dx.doi.org/10.1093/biolinnean/blx127.

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