Bibliographies thématiques / Aridità

Littérature scientifique sur le sujet « Aridità »

Auteur : Grafiati
Publié le 11 mars 2023

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Articles de revues sur le sujet "Aridità"

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De Angelis, P., G. de Dato, D. Spano, P. Duce, C. Sirca, C. Asunis, G. Pellizzaro, C. Cesaraccio, S. Sechi et G. Scarascia Mugnozza. « A new long-term experimental area for the assessment of the effects of climate warming and seasonal drought on a Mediterranean shrubland community ». Forest@ - Rivista di Selvicoltura ed Ecologia Forestale 2, no 1 (10 mars 2005) : 37–51. http://dx.doi.org/10.3832/efor0260-0020037.

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Vlăduţ, Alina, Nina Nikolova et Mihaela Licurici. « Aridity assessment within southern Romania and northern Bulgaria ». Hrvatski geografski glasnik/Croatian Geographical Bulletin 79, no 2 (janvier 2017) : 5–26. http://dx.doi.org/10.21861/hgg.2017.79.02.01.

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Rocha, Guadalupe, Antoine Le Queré, Arturo Medina, Alma Cuéllar, José-Luis Contreras, Ricardo Carreño, Rocío Bustillos et al. « Diversity and phenotypic analyses of salt- and heat-tolerant wild bean Phaseolus filiformis rhizobia native of a sand beach in Baja California and description of Ensifer aridi sp. nov. » Archives of Microbiology 202, no 2 (28 octobre 2019) : 309–22. http://dx.doi.org/10.1007/s00203-019-01744-7.

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Abstract In northern Mexico, aridity, salinity and high temperatures limit areas that can be cultivated. To investigate the nature of nitrogen-fixing symbionts of Phaseolus filiformis, an adapted wild bean species native to this region, their phylogenies were inferred by MLSA. Most rhizobia recovered belong to the proposed new species Ensifer aridi. Phylogenetic analyses of nodC and nifH show that Mexican isolates carry symbiotic genes acquired through horizontal gene transfer that are divergent from those previously characterized among bean symbionts. These strains are salt tolerant, able to grow in alkaline conditions, high temperatures, and capable of utilizing a wide range of carbohydrates and organic acids as carbon sources for growth. This study improves the knowledge on diversity, geographic distribution and evolution of bean-nodulating rhizobia in Mexico and further enlarges the spectrum of microsymbiont with which Phaseolus species can interact with, including cultivated bean varieties, notably under stressed environments. Here, the species Ensifer aridi sp. nov. is proposed as strain type of the Moroccan isolate LMR001T (= LMG 31426T; = HAMBI 3707T) recovered from desert sand dune.
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Sugden, Andrew M. « Thresholds of aridity ». Science 367, no 6479 (13 février 2020) : 752.14–754. http://dx.doi.org/10.1126/science.367.6479.752-n.

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Wu, Yanfeng, Guangxin Zhang, Hong Shen, Y. Jun Xu et Batur Bake. « Attribute Analysis of Aridity Variability in North Xinjiang, China ». Advances in Meteorology 2016 (2016) : 1–11. http://dx.doi.org/10.1155/2016/9610960.

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Identifying the dominant meteorological factors affecting aridity variability can improve our understanding of climate change and its future trend in arid and semiarid regions. This study investigated the spatiotemporal aridity variability in North Xinjiang, China, from 1961 to 2013, based on the UNESCO aridity index (precipitation/potential evapotranspiration), and analyzed its association with meteorological factors. The results suggest that North Xinjiang is becoming more humid with an increasing trend in aridity index. Precipitation, temperature, and relative humidity have positive correlation with aridity, and evapotranspiration, sunshine hours, and wind speed have negative correlation with aridity. Wind speed and sunshine hours have a higher sensitivity and more contribution to aridity. This study provides an understanding of the effect of recent climate change on drought in northwest China.
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Prasad, Rajendra, et Hari Singh. « Bharat mein 1990-1999 ke dauraan shushkata visangatiyon ka kshetreey avem saamayik vishleshan ». MAUSAM 53, no 4 (13 janvier 2022) : 447–56. http://dx.doi.org/10.54302/mausam.v53i4.1659.

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Aridity Anomaly Index (AAI), based on Thornthwaite’s water balance technique, has been used to identify the extent and persistence of aridity anomalies over 33 sub-divisions of India during a period of 10 years from 1990 to 1999. Regional and temporal analysis has been carried out to identify the areas and periods of intense and prolonged persistence. This study has shown that 1992 was worst hit by the aridity conditions, which emerged in 5 or more fortnights. All sub-divisions of north India were affected by moderate aridity during 1990, 1992-94 and 1999. Similarly, all sub-divisions of peninsular India were influenced by moderate aridity during 1991, 1993 and 1999. Severe aridity appeared in all sub-divisions of peninsular India during 1990. The duration of severe aridity was less than that of moderate aridity during all years. Moderate and severe aridity appeared simultaneously in 5 or more fortnights in maximum 9 sub-divisions in 1992 and occurred during maximum 5 years in Madhya Maharashtra. Moderate aridity in 5 or more fortnights emerged each year during 1990 to 1999 in coastal Andhra Pradesh. In 1991, maximum 55% sub-divisions were affected by severe aridity in 9th fortnight, whereas Saurashtra & Kutch was affected in 1996 and north Interior Karnataka in 1999 during maximum 7 fortnights. In the year 1992, maximum number of sub-divisions under moderate and severe persistence was 70% and 24% respectively. In north India, moderate persistence appeared in east Rajasthan in all nine years except 1996, with its longest duration of 8 fortnights in 1995. West Madhya Pradesh, in peninsular India, was affected by moderate aridity during 7 fortnights in each year during the period of study from 1990 to 1999.
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Ahmed, Kamal, Shamsuddin Shahid, Xiaojun Wang, Nadeem Nawaz et Najeebullah Khan. « Spatiotemporal changes in aridity of Pakistan during 1901–2016 ». Hydrology and Earth System Sciences 23, no 7 (19 juillet 2019) : 3081–96. http://dx.doi.org/10.5194/hess-23-3081-2019.

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Abstract. The changing characteristics of aridity over a larger spatiotemporal scale have gained interest in recent years due to climate change. The long-term (1901–2016) changes in spatiotemporal patterns of annual and seasonal aridity during two major crop growing seasons of Pakistan, Kharif and Rabi, are evaluated in this study using gridded precipitation and potential evapotranspiration (PET) data. The UNESCO aridity index was used to estimate aridity at each grid point for all the years between 1901 and 2016. The temporal changes in aridity and its associations with precipitation and PET are evaluated by implementing a moving window of 50 years of data with an 11-year interval. The modified Mann–Kendall (MMK) trend test is applied to estimate unidirectional change by eliminating the effect of natural variability of climate, and Pettitt's test is used to detect year of change in aridity. The results revealed that the climate over 60 % of Pakistan (mainly in southern parts) is arid. The spatial patterns of aridity trends show a strong influence of the changes in precipitation on the aridity trend. The increasing trend in aridity (drier) is noticed in the southwest, where precipitation is low during Kharif, while there is a decreasing trend (wetter) in the Rabi season in the region which receives high precipitation due to western disturbances. The annual and Kharif aridity is found to decrease (wetter) at a rate of 0.0001 to 0.0002 per year in the northeast, while Kharif and Rabi aridity are found to increase (drier) at some locations in the south at a rate of −0.0019 to −0.0001 per year. The spatial patterns of aridity changes show a shift from arid to the semi-arid (wetter) climate in annual and Kharif over a large area while showing a shift from arid to hyper-arid (drier) region during Rabi in a small area. Most of the significant changes in precipitation and aridity are observed in the years between 1971 and 1980. Overall, aridity is found to increase (drier) in 0.52 %, 4.44 % and 0.52 % of the area and decrease (wetter) in 11.75 %, 7.57 % and 9.66 % of the area for annual, Rabi and Kharif seasons respectively during 1967–2016 relative to 1901–1950.
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Harshada Ragunathan, Krithika C, Divya G, Nishanthi L, Priya Ramani et Gayathri P S. « Aridity In Senior Citizens ». International Journal of Research in Pharmaceutical Sciences 11, SPL4 (21 décembre 2020) : 2381–84. http://dx.doi.org/10.26452/ijrps.v11ispl4.4481.

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Hyposalivation contributes to several health problems. It can produce serious adverse effects on one's quality of life. The prevalence of dry mouth increases with age, and approximately 30% of those aged 60 years and old are being affected. Ageing and medication are the salient causes of hyposalivation / Xerostomia. The study aims to analyse the salivary flow rate of senior citizens by a questionnaire method & to confirm through clinical evaluation. The objective of the study is to show the importance of clinical evaluation of the oral cavity in estimating the salivary flow. The study was conducted among 40 senior citizens of age 60 & above. The assessment of dry mouth was done by questioner method and by collecting unstimulated saliva. The collected data were subjected to statistical analysis, and chi-square test was performed. It showed that patients who believed that they were pretty fine also had hyposalivation clinically. 57.5% of total participants had less salivary flow rate. Also, 67.5% of participants showed oral manifestation of periodontitis with 7.5% mirror stick appearance. 32.5% of participants had dry-mouth out of which most of them were females and had no drug history. Even though there are many signs and symptoms for oral dryness, clinical evaluation always stands first in diagnosis. Patient under drug therapy and elderly patient's routine dental checkup can help them to know about their dental and general health status.
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Blumenthal, Scott A., Naomi E. Levin, Francis H. Brown, Jean-Philip Brugal, Kendra L. Chritz, John M. Harris, Glynis E. Jehle et Thure E. Cerling. « Aridity and hominin environments ». Proceedings of the National Academy of Sciences 114, no 28 (26 juin 2017) : 7331–36. http://dx.doi.org/10.1073/pnas.1700597114.

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Aridification is often considered a major driver of long-term ecological change and hominin evolution in eastern Africa during the Plio-Pleistocene; however, this hypothesis remains inadequately tested owing to difficulties in reconstructing terrestrial paleoclimate. We present a revised aridity index for quantifying water deficit (WD) in terrestrial environments using tooth enamel δ18O values, and use this approach to address paleoaridity over the past 4.4 million years in eastern Africa. We find no long-term trend in WD, consistent with other terrestrial climate indicators in the Omo-Turkana Basin, and no relationship between paleoaridity and herbivore paleodiet structure among fossil collections meeting the criteria for WD estimation. Thus, we suggest that changes in the abundance of C4 grass and grazing herbivores in eastern Africa during the Pliocene and Pleistocene may have been decoupled from aridity. As in modern African ecosystems, other factors, such as rainfall seasonality or ecological interactions among plants and mammals, may be important for understanding the evolution of C4 grass- and grazer-dominated biomes.
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Hrnjak, Ivana, Tin Lukić, Milivoj B. Gavrilov, Slobodan B. Marković, Miroslava Unkašević et Ivana Tošić. « Aridity in Vojvodina, Serbia ». Theoretical and Applied Climatology 115, no 1-2 (23 avril 2013) : 323–32. http://dx.doi.org/10.1007/s00704-013-0893-1.

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Thèses sur le sujet "Aridità"

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Burgess, Tony L. « Agave Adaptation to Aridity ». University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/554187.

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To show features of Agave taxa adapting to arid habitats, comparative studies at three taxonomic levels in the genus are presented. There is a brief review of Agave physiology and some aspects of recent evolution are discussed. Comparisons among species groups within the genus show several traits differentiating desert species from related taxa. Related taxa in the Deserticolae group are examined over a transect in Baja California, revealing patterns linking leaf shape to climate. In a comparison of leaves of A. desert] Engelm. along an elevational gradient, high intrapopulation variation obscures differences between the sites. Results are summarized as hypotheses to be tested.
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Fouet, Caroline. « Caractérisation de quelques phénotypes liés à l'aridité et à la température chez Anopheles gambiae sensu stricto (Giles, 1902) ». Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20155/document.

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Grâce aux progrès expérimentaux permettant d'étudier deux phénotypes qui sont d'un intérêt majeur dans la compréhension des capacités d'adaptation d'A. gambiae s.s. à son environnement. Les différences de résistance à la dessiccation mises en évidence entre les différents caryotypes liés à l'inversion chromosomique 2La et entre les formes moléculaires M et S offrent des pistes intéressantes pour l'identification de facteurs génétiques impliqués dans la divergence écologique au sein de ce complexe d'espèces
Thanks to progress in sequencing, the genomes of many organisms are known and available. Thus, functional genomics, the elucidation of gene function in sequenced genome, is currently booming. However, there is a gap between our growing knowledge in genetic and the current sparse information on phentoypic data ( "phenotype gap"). All organisms whose genome has been sequenced are facing this problem, including Anopheles gambiae.Anopheles gambiae sensu lato is a complex of sibling species, indistinguishable from a morphological point of view, present on almost the entire African continent. A. gambiae demonstrates an extreme environmental ubiquity and the characterization of phenotypes associated with adaptation to varying environments as well as the identification of genes involved in this adaptation is one of the main research axes in the post-genome area of this major malaria vector.We have studied some phenotypes associated with aridity and temperature in the nominal species of the A. gambiae complex. These two parameters are discriminent in the distribution of molecular forms and chromosomal inversions that characterize this species and may be involved in ecological divergence and speciation. We first measured desiccation resistance of adult mosquitoes of A. gambiae s.s. and we then studied the preferred temperatures of larvae in a choice device set-up (the shuttlebox). We compared the thermoregulation behavior and thermal preferences of a laboratory strain with field larvae of A. gambiae s.s. We also presented preliminary data on the preferred temperatures measured in field larvae of the S and M molecular forms.From a technical point of view, we improved an existing device for testing the survival of mosquitoes in highly desiccated conditions by coupling it with a video surveillance system, which help to increase the accuracy in determining the survival time, to avoid disturbing the system during the experiment and allow to test relatively large numbers of individuals. This study revealed a significant association between the 2La chromosomal inversion and resistance to desiccation in A. gambiae and highlighted the role of body size in the survival of this mosquito in dry environments.We also adapted a new device to study experimentally the thermopreference of A. gambiae s.s. larvae. The results showed that laboratory larvae and field M molecular form larvae had similar thermal preferences, consistent with the values of temperature usually found in natural breeding sites. In addition, the S molecular form larvae from southern Cameroon had preferences similar to those of northern Cameroon, regardless of karyotypes related to chromosomal inversions. In addition, the comparison of data for the M and S molecular forms larvae revealed that there was no significant difference in thermal preferences or in thermoregulatory behavior.Our results have contributed to the development of two experimental devices to study two phenotypes that are of major interest in understanding the adaptation of A. gambiae s.s. to its environment. The differences in desiccation resistance between the different karyotypes associated with the 2La chromosomal inversion and between the M and S molecular forms offer interesting new possibilities for the identification of genetic factors involved in their ecological divergence
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Gortan, Emmanuelle. « Misura dello stato idrico di fraxinus ornus L. quale biomonitor dell'aridità ambientale in siti diversi del carso triestino ». Doctoral thesis, Università degli studi di Trieste, 2008. http://hdl.handle.net/10077/2658.

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2006/2007
L'aridità è una condizione ambientale che comporta una ridotta disponibilità d'acqua per le piante all'interno del suolo. La disponibilità d'acqua rappresenta, unitamente alla temperatura, il fattore ambientale che più di ogni altro condiziona la distribuzione e la produttività primaria della vegetazione. Poiché una prolungata aridità ambientale ha serie conseguenze sulla produttività degli ecosistemi forestali e sulla sopravvivenza di alcune specie vegetali meno competitive di altre in tali condizioni, è di fondamentale importanza quantificare il livello di aridità ambientale per poterne prevedere l'impatto attuale e le tendenze in atto. Il progetto di ricerca si poneva quindi l’obiettivo di individuare e definire un indice di aridità ambientale, che consentisse di rappresentare le relazioni che la pianta contrae con l’acqua presente nell’ambiente in funzione della risposta fisiologica della pianta al variare del contenuto idrico del suolo, attraverso un valore unico a significato ecofisiologico. L'individuazione di un parametro ecofisiologico in grado di stimare in modo affidabile l'impatto dello stress idrico poneva le basi per valutare possibili correlazioni con parametri ottenibili con il telerilevamento. Un'altra finalità del lavoro era, infatti, l'individuazione di un parametro di riferimento mediante l'utilizzo di tecniche di telerilevamento da satellite da applicare nello “scaling up” ecologico, che a partire dallo studio dell'impatto dello stress idrico su singole specie potesse indagare sistemi di vegetazione sempre più grandi nell'ottica di sviluppare una visione olistica di grandi aree in relazione all'aridità ambientale. La specie vegetale che è stata scelta come potenziale biomonitor è Fraxinus ornus L. ossia l'orniello, che è stato selezionato in quanto trattasi di una specie vegetale che si distingue per la notevole capacità di resistenza a condizioni di stress idrico e proprio per questa sua capacità, è una specie diffusa in una grande varietà di ambienti. L'area di studio scelta è stata la provincia di Trieste ed in particolare l'area carsica. Questa zona, infatti, offre l'opportunità di eseguire significativi biomonitoraggi per valutazioni quantitative e qualitative sull'ambiente, in quanto presenta una elevata variabilità di substrati litologici, costituiti da rocce soggette a fenomeni di dissoluzione da parte delle acque meteoriche chimicamente aggressive (rocce carsificabili), a cui sono associati diversi tipi di circolazione idrica. La presenza di una fitta rete di fessure e fratture nei substrati geologici a tratti determina un forte drenaggio dell'acqua all'interno del suolo dovuto a percolamento della stessa verso gli strati più profondi. Nella zona del Carso triestino, sono state selezionate 21 stazioni in base ad un criterio geomorfologico noto come carsificabilità, che misura in modo indiretto e qualitativo la capacità di campo di un suolo, e in modo tale da ricoprire tutto il territorio dell'area carsica all'interno della provincia di Trieste. Al fine di identificare quale fosse il parametro fisiologico o morfologico che meglio si addicesse allo scopo della ricerca, sono stati misurati nel periodo da Maggio a Settembre i parametri relativi alle relazioni pianta-acqua generalmente correlati allo stress idrico e cioè la conduttanza fogliare al vapore d'acqua (gL), il potenziale dell'acqua della foglia (Ψfoglia) e la conduttanza idraulica della foglia (Kfoglia). Contestualmente, sono stati misurati anche i diametri dei vasi xilematici. Grazie all'analisi di questi parametri è stato possibile eseguire uno studio biofisico accurato del comportamento idraulico dell'orniello in condizioni di limitazione della disponibilità d'acqua. Da questi dati emerge che la conduttanza fogliare al vapore d'acqua (gL) è il parametro più affidabile a rappresentare l'indice di aridità ambientale, in quanto è risultato essere il più sensibile alle variazioni nella disponibilità d'acqua. Il tentativo di integrare i dati di campo relativi a gL con quelli ottenuti mediante elaborazione di immagini satellitari non ha portato ai risultati sperati. L'indice ottenuto da dati telerilevati è risultato poco promettente come indice di riferimento per la realizzazione di uno “scaling-up”, in quanto non è risultato essere in grado di rilevare condizioni di stress idrico in aree caratterizzate da forte drenaggio dell'acqua (aree ad alta carsificabilità). L'applicabilità delle tecniche di telerilevamento da satellite nel monitoraggio dell'aridità ambientale risulta quindi fortemente limitata dalla struttura geomorfologica del territorio oggetto di studio.
XX Ciclo
1973
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Touzeau, Alexandra. « L'Egypte ancienne, une civilisation face à un changement climatique : le message isotopique (C, N, O, S) des tissus vivants momifiés ». Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10104.

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L'Egypte, territoire aride, dépend essentiellement du Nil pour l'irrigation de ses terres agricoles. La variabilité temporelle de la crue du fleuve a donc pu affecter directement la dynamique de la population égyptienne. Ici, cette hypothèse est testée en étudiant la variation du climat pendant l'Egypte ancienne parallèlement à des indicateurs du mode de vie des égyptiens. La variation dans le temps du δ18Ow de l'eau du Nil est reconstituée à partir des valeurs de δ18Op du phosphate de l'apatite de momies égyptiennes. L'augmentation de +3 ‰ du δ18Ow de l'eau du Nil entre la période Prédynastique (5500BP) et la période Gréco-Romaine (2000BP) est causée par une modification des conditions de précipitation au-dessus des sources du Nil. Elle traduit soit une hausse de température proche de 2°C soit une baisse des précipitations mensuelles d'environ 140 mm. Ici, l'hypothèse d'une aridification est privilégiée : en effet des mesures de δ18Op sur des poissons du Nil permettent de calculer une température du Nil à la période Gréco-Romaine comparable à l'actuelle. Le changement climatique constaté semble avoir peu d'impact sur la civilisation égyptienne. En effet la population égyptienne s'accroît nettement pendant la période considérée et le régime alimentaire est resté fondé sur les plantes en C3, peu adaptées aux milieux arides, avec une consommation rare de poissons et de protéines animales. La réduction de la crue a sans doute été compensée par les progrès technologiques de la civilisation égyptienne (chadouf, drainage) qui ont rendu possible la mise en culture de nouvelles terres
Egypt is an arid territory, which essentially depends on the Nile river for the irrigation of its agricultural lands. The temporal variability of the river flood thus may have affected directly the dynamics of the Egyptian population. Here, this hypothesis is tested by studying the variation of the climate during Ancient Egypt concurrently to indicators of the life habits of the Egyptians. The variation with time of the δ18Ow of the Nile water is reconstructed from the δ18Op of the apatite phosphate of Egyptian mummies. The increase of +3 ‰ in the Nile water δ18Ow between the predynastic period (5500BP) and the Greco-Roman Period (2000BP) is caused by a change in the conditions of precipitation above the Nile sources. This increase can be the result of an increase in temperature of about +2 °C or of a decrease in the monthly amount of precipitation of about 140 mm. Here, the hypothesis of aridification is preferred: in effect, δ18Op measures on Nile fishes permit to infer a Nile water temperature at the Greco-Roman Period similar to the present-day one. The climatic change seems to have had little impact on the Egyptian civilization. In effect the Egyptian population increases considerably during the selected period and its diet remains funded on C3- plants, feebly adapted to arid environments, with a rare consumption of fishes or other animal protein. The decrease of the flood was admittedly compensated by the technological advances of the Egyptian civilization (shaduf, drainage) which allowed the cultivation of newly reclaimed lands
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Reyes, Serrano Héctor Fabian. « La tierra se mueve : les transformations de la propriété agricole dans une zone aride : la province du Limarí (Région de Coquimbo, Chili) ». Phd thesis, Université d'Orléans, 2009. http://tel.archives-ouvertes.fr/tel-00455240.

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La terre agricole du Limarí change de mains, parfois très lentement, parfois très rapidement. La concentration de la propriété de la terre, initiée avec les mercedes de tierra faites par la couronne espagnole à partir du 16ème siècle, ne sera interrompue que par la réforme agraire des années 1960. Le courant économique néolibéral confirmé avec force au Chili à partir de 1973, marque le début d'une nouvelle période de transformation de la propriété et de la production agropastorale qui se maintient actuellement. De nouveaux propriétaires et de nouvelles dynamiques économiques et sociales se développent dans le Limarí. Dans le contexte politique qui a mis en évidence le problème de paysans sans terre dans l'Amérique latine, l'accès à la terre agricole donne t'elle un meilleur accès à la croissance ? Le fait qu'un plus grand nombre devienne propriétaire de la terre transforme-t-il la relation entre l'agriculteur, la terre et la production ? La relation entre l'accès à la terre, la production et le bien-être des agriculteurs les moins favorisés n'est pas homogène mais présente une vaste gamme de nuances. L'accès à l'eau, au financement, à l'information et à la formation sont tout aussi déterminants. L'avenir des propriétaires-agriculteurs actuels, et de ceux qui aspirent à le devenir, n'est pas tout tracé et dépend de facteurs devenus imprévisibles. A travers les données des recensements agro-pastoraux et les données fiscales, et à travers des exemples détaillés, ce travail aborde l'évolution de la structure foncière dans une province dont l'agriculture s'est développée de façon spectaculaire malgré ou grâce à l'aridité, malgré ou grâce au néolibéralisme.
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Neilson, Julia W., Katy Califf, Cesar Cardona, Audrey Copeland, Treuren Will van, Karen L. Josephson, Rob Knight et al. « Significant Impacts of Increasing Aridity on the Arid Soil Microbiome ». AMER SOC MICROBIOLOGY, 2017. http://hdl.handle.net/10150/625716.

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Global deserts occupy one-third of the Earth's surface and contribute significantly to organic carbon storage, a process at risk in dryland ecosystems that are highly vulnerable to climate-driven ecosystem degradation. The forces controlling desert ecosystem degradation rates are poorly understood, particularly with respect to the relevance of the arid-soil microbiome. Here we document correlations between increasing aridity and soil bacterial and archaeal microbiome composition along arid to hyperarid transects traversing the Atacama Desert, Chile. A meta-analysis reveals that Atacama soil microbiomes exhibit a gradient in composition, are distinct from a broad cross-section of nondesert soils, and yet are similar to three deserts from different continents. Community richness and diversity were significantly positively correlated with soil relative humidity (SoilRH). Phylogenetic composition was strongly correlated with SoilRH, temperature, and electrical conductivity. The strongest and most significant correlations between SoilRH and phylum relative abundance were observed for Acidobacteria, Proteobacteria, Planctomycetes, Verrucomicrobia, and Euryarchaeota (Spearman's rank correlation [r(s)] = >0.81; false-discovery rate [q] = <= 0.005), characterized by 10- to 300-fold decreases in the relative abundance of each taxon. In addition, network analysis revealed a deterioration in the density of significant associations between taxa along the arid to hyperarid gradient, a pattern that may compromise the resilience of hyperarid communities because they lack properties associated with communities that are more integrated. In summary, results suggest that arid-soil microbiome stability is sensitive to aridity as demonstrated by decreased community connectivity associated with the transition from the arid class to the hyperarid class and the significant correlations observed between soilRH and both diversity and the relative abundances of key microbial phyla typically dominant in global soils. IMPORTANCE We identify key environmental and geochemical factors that shape the arid soil microbiome along aridity and vegetation gradients spanning over 300 km of the Atacama Desert, Chile. Decreasing average soil relative humidity and increasing temperature explain significant reductions in the diversity and connectivity of these desert soil microbial communities and lead to significant reductions in the abundance of key taxa typically associated with fertile soils. This finding is important because it suggests that predicted climate change-driven increases in aridity may compromise the capacity of the arid-soil microbiome to sustain necessary nutrient cycling and carbon sequestration functions as well as vegetative cover in desert ecosystems, which comprise one-third of the terrestrial biomes on Earth.
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Rey, Carine. « Détection de l’évolution convergente à l’échelle génomique : développement de méthodes et étude des adaptations indépendantes à la vie en milieu aride chez les rongeurs ». Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEN060.

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La convergence phénotypique, c’est-à-dire l’acquisition indépendante de caractères similaires par des espèces différentes, est omniprésente dans la nature et a été souvent étudiée. Mais ce processus évolutif n’est pas bien compris. Par exemple, de nombreux chercheurs cherchent à comprendre s’il existe des bases génétiques convergentes sous-jacentes à ces convergences phénotypiques.Quelques substitutions convergentes corrélées à un phénotype convergent ont été décrites dans la littérature, mais il existe peu d’études à l’échelle génomique. Ceci peut s’expliquer par deux problèmes méthodologiques : 1/ D’une part, la difficulté de créer des jeux de données multi-espèces pour des analyses comparatives. 2/ D’autre part, le manque de méthodes dédiées à la détection de la convergence à l’échelle génomique.Au cours de ma thèse, j’ai proposé des solutions à ces deux défis. Dans un premier temps, j’ai créé un programme (CAARS) permettant d’automatiser l’assemblage de jeux de données composés de familles d’orthologues à partir de données RNA-Seq. Puis, j’ai créé un outil (PCOC) pour étudier les substitutions convergentes au sein de séquences codantes, basé sur l’identification de changements de profils d’acides aminés. Ces outils ont été développés dans un souci de reproductibilité et de facilité d’utilisation. J’ai ensuite étudié la capacité de différentes méthodes, dont PCOC, à détecter des substitutions convergentes en présence de facteurs confondants. Enfin, j’ai appliqué ces méthodes à un cas biologique où j’ai cherché à caractériser les bases génomiques de l’adaptation aux milieux arides chez les rongeurs
Phenotypic convergence, the independent acquisition of similar characters by different species,is widespread in nature and has been extensively studied. But this evolutionary process is not well understood. For example, many researchers seek to understand whether there are convergent genetic bases underlying these phenotypic convergences.Some convergent substitutions correlated with a convergent phenotype have been described in the literature, but there are few studies at the genome scale. This can be explained by two methodological problems : 1 / On the one hand, the difficulty of creating multi-species datasets for comparative analyses. 2 / On the other hand, the lack of dedicated methods to detect convergence at the genomic scale.During my thesis, I proposed solutions to these two challenges. As a first step, I created a program (CAARS) to automate the assembly of datasets composed of orthologous families from RNA-Seq data. Then I created a tool (PCOC) to study convergent substitutions within coding sequences, based on the identification of amino acid profile changes rather than strict amino acid changes. These tools have been developed for the sake of reproducibility and ease of use. I then studied the ability of different methods, including PCOC, to detect convergent substitutions in the presence of confounding factors. Finally, I applied these methods to a biological case where I sought to characterize the genomic bases of adaptation to arid environments in rodents
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Spinks, Andrew Charles. « Sociality in the common mole-rat, Cryptomys hottentotus hottentotus : the effects of aridity ». Doctoral thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/23681.

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This study addresses the extrinsic factors which have shaped the evolution and maintenance of sociality in the African mole-rats. Specifically, the common mole-rat was used as a model to assess the Aridity Food-Distribution Hypothesis (AFDH), as an explanation for the evolution of bathyergid sociality. The AFDH correlates mole-rat sociality with habitat aridity and the pattern of food distribution. Aspects relating to ecological constraints, foraging behaviour, population demography, reproductive biology and aggressive behaviour were compared between an arid and a mesic population of C. h. hottentotus, to assess how inter-habitat divergence in ecological attributes has influenced social behaviour within these two populations. In evaluating the AFDH as an explanation for the evolution of sociality within C. h. · hottentotus two broad questions were addressed: (1) do the assumptions of the AFDH hold true i.e. do arid and mesic habitats exhibit ecological differences, specifically with regard to the pattern of resource dispersion and the energetic costs of foraging, which influence foraging risks and consequently the costs of dispersal? and (2) do these inter-habitat differences have implications for bathyergid social evolution i.e. do the common mole-rat populations inhabiting arid and mesic areas exhibit regional differentiation in social behaviour? Substantial inter-site divergence in ecological characteristics, notably climate and resource attributes, were revealed in this study. Rainfall at the arid site was markedly lower and more sporadic, and evaporation levels significantly higher, than at the mesic site. Moreover, thermal constraints were more limiting at the arid site. These features will greatly elevate the costs of soil excavation and the risks of hyperthermia, severely restricting the occurrence of suitable burrowing opportunities at the arid locality. Consequently, foraging will be severely constrained in this area. At the mesic site, higher, more predictable rainfall, low evaporation rates and reduced thermal constraints will translate into more suitable burrowing opportunities for much, if not all, of the year. Regional differentiation in food resource characteristics was also evident. Although geophytes were clumped at both study localities, the density of geophytes was lower and the distance between geophytes or geophyte clumps concomitantly greater at the arid relative to the mesic site. Differences in resource dispersion in turn influenced the patterns of foraging. In response to the low geophyte density and associated longer foraging distances, burrow systems were notably longer and more linear at the arid site. Furthermore, food storage and in situ harvesting were essential components of cooperative foraging in C. h. hottentotus as they minimised the risks of starvation, particularly in arid habitats. Thus, resource characteristics together with the climatic restrictions on burrowing in arid areas may have a marked impact on foraging behaviour, imposing severe constraints on the mole-rats occurring there and ultimately shaping their foraging responses. Together, these factors satisfactorily account for the underlying premise of the AFDH, that arid and mesic habitats exhibit ecological differences with regard to the pattern of resource dispersion and the energetic costs of foraging, which are likely to influence foraging risks and the costs of dispersal. In evaluating the AFDH, the second question which needed to be addressed was whether the study populations exhibited divergence in their social behaviour. The populations revealed no differences in absolute group size or in reproductive characteristics which were related to the effects of aridity per se. However, distinct inter-population divergence was readily apparent in phenotypically plastic traits such as dispersal behaviour and xenophobia. Clear differences were evident between the arid and mesic sites in both the quantitative and qualitative nature of dispersal; dispersal was markedly constrained at the arid site and colonies demonstrated greater temporal stability, with more predictable temporal group membership. The ecological constraints on successful foraging at the arid site will curb opportunities for dispersal and promote cooperation in the C. h. hottentotus occurring there. Colony members should therefore maximise their inclusive fitness by natal philopatry, delayed dispersal and cooperative foraging. Inter-site differences were also apparent in the response of colony members to foreign conspecifics. Common mole-rats from the arid site were markedly more xenophobic than those from the mesic site, and aggressively rejected foreigners. For arid-occurring populations, the fitness penalties for failing to exclude foreigners from the colony burrow system and associated resources, will be more severe than for mesic-occurring populations, resulting in heightened levels of xenophobia. Again, colony cohesion and cooperation in arid areas are essential to individual survival and inclusive fitness. The regional differences in dispersal patterns and xenophobia revealed in this investigation may reflect adaptive variation in social behaviour between the study populations, and the results suggest that delayed dispersal and cooperation may be more crucial to individual survival in arid than in mesic areas. As such these findings provide support for the underlying contention of the AFDH that ecological constraints on foraging in arid areas have promoted a greater degree of social elaboration in mole-rats occurring there. This study provides persuasive support for the AFDH as an explanation for the adaptive significance of social behaviour and cooperation in the common mole-rat, and together with other investigations, suggests that the AFDH provides a valid explanation for the evolution of group-living in the Bathyergidae.
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Mpofu, Khulekani. « Evaluation of the performance of community-based natural resources management (CBNRM) projects along an aridity gradient in Botswana ». Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1006063.

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The Botswana Community Based Natural Resources Management (CBNRM) programme started in 1989. Its aims were to promote sustainable development through sustainable natural resources management and utilisation to improve rural livelihoods. The country CBNRM programme has recorded mixed outcomes and this has raised questions on the programme performance throughout the country. Since the programme has been recognised as one of the eight main livelihood strategies for rural communities in Botswana, there was a need to evaluate the programme performance and determine the factors that influence it. This thesis therefore evaluated the performance of CBNRM projects along an aridity gradient in Botswana and by so doing answered the two research questions of: (1) What factors influence the performance of CBNRM? And (2) how does aridity influence the performance of CBNRM programmes? Performance was determined in terms of financial benefits generated by CBNRM projects and the projects adherence to the CBNRM principles. Data were collected from seven selected CBNRM projects covering three aridity zones (wet, medium rainfall and dry areas) in the country. Data were also collected from key informants and community based organisations (CBO) project managers. Research findings have indicated differences in the performance of CBNRM projects across the identified three aridity zones. Factors that influenced the performance of CBNRM projects varied among the three aridity zones. These factors included: existence of complimentary rules and regulations for managing CBNRM projects; literacy levels of communities involved in CBNRM; ethnic composition of the project communities; historic and current socio-economic trends within communities; collaboration between CBNRM institutions and other local level institutes; amount of benefits generated through the projects; ability of institutions to resolve outstanding issues in time and type of CBNRM project. Research results also indicated that there was variation in the performance of CBNRM projects across the three aridity zones. Aridity was found to directly influence the performance of CBNRM projects through its influence on the amount of revenues that projects generated.
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Ben, Brahim Mohamed. « Le sillon de Boudenib (SE-Maroc) : structuration morphotectonique, hamadas tertiaires et paléoaltérations associées, morphogenèse quaternaire et aridité actuelle ». Paris 1, 1994. http://www.theses.fr/1994PA010597.

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Le but de cette thèse est d'étudier le rôle de la tectonique et du climat dans l'élaboration des reliefs de grande et de moyenne échelle. L'approche pluridisciplinaire y constitue le cadre méthodologique. Il est montré que le sillon de Boudenib se situe au croisement de trois unités géotectoniques majeures : planafricaine, hercynienne et atlasique. Cette structuration transparait dans la dissymétrie des formes de relief. Le remplissage sédimentaire a enregistré la totalité des phénomènes qui se sont succédés à l'interieur du bassin et sur ses bordures. L'évolution préturonienne est marquée par le contrôle des facteurs tectoniques, climatiques et eustatiques. À partir du crétacé supérieur, seuls les facteurs tectoniques ou climatiques rythment l'évolution. L'étude du Piémont hamadien de Boudenib apporte des faits nouveaux sur la tectonique atlasique, la nature des dépôts et les alterations associées dont les silicifications y font l'originalité. Deux grands types de silicification ont été distingués : silicification pédogénétique associée à La Hamada de Boudenib I (eocene inférieur) et silicification de nappe affectant la Hamada du Guir (néogene). Enfin, la morphogeneèse tertiaire est marquee par la juxtaposition d'un Piémont d'accumulation à un Piémont d'érosion. La phase fini-pliocène ? met en place les unités de relief majeurs, mais les conditions morphogeniques quaternaires sont plutôt placées sous le contrôle du climat, évoluant vers l'aride, et ce malgré une néotectonique active jusqu'au. .
The purpose of this research is to study the role of tectonic and climat in the elaboration of reliefs of high and middle scale. The pluridisciplinary approch constitues the methodologic frame. It is shown that boudenib grooc is situated in the intersection of three major geotectonic units : panafrican, hercynian and atlasic. The dissymetry of topographical features reflects this structure. The sedimentation recorded the total phenomenon which succeeded inside the basin as well as on the borders. Therefore, dissymetry between eastern and western parts of the boudenib groov has been constant in the evolution. The preturonian evolution was caracterized by the control of tectonic factors, climat and eustatic ones. However, from the upper cretaceous only tectonic and climatic factors predominated. The study of hamadas deposits on the piedmont of boudenib brings new factors about the atlasic tectonic, the kind of deposits and associeted paleoweathering in which silicification makes the originaly. Two types of silicification were difined : pedogenetic silicification in the lower part of "hamada de boudenib" (lower eocene) and ground water silicification in the "hamada de guir" (neogene). Eventually, the tertiary morphogenisis is caracterized by the juxtaposition of two piedmonts : accumulation and erosion. .
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Livres sur le sujet "Aridità"

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Mainguet, Monique. Aridity. Berlin, Heidelberg : Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-662-03906-9.

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Umez, Uche Peter. Aridity of feelings. Owerri, Nigeria : Edu-Edy Publications, 2006.

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Aridity : Droughts and human development. Berlin : Springer, 1999.

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Thérien, Michel A., 1948- (autograph), dir. L' aridité des fleuves : Poèmes. Ottawa : Éditions David, 2004.

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Massmann, Adam. Estimating ecosystem evaporation response to aridity with theory and causality. [New York, N.Y.?] : [publisher not identified], 2022.

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Worster, Donald. Rivers of empire : Water, aridity, and the growth of the American West. New York : Pantheon Books, 1985.

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Richard, Moorsom, Franz Jutta, Mupotola Moono, Namibian Economic Policy Research Unit., Namibia. Ministry of Agriculture, Water, and Rural Development. et United Nations Environment Programme, dir. Coping with aridity : Drought impacts and preparedness in Namibia--experiences from 1992/93. Frankfurt am Main : Brandes & Apsel, 1995.

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Prandi, Stefano. Il "diletto legno" : Aridità e fioritura mistica nella Commedia. Firenze : L.S. Olschki, 1994.

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Greenfield, Eric J. Tree cover and aridity projections to 2060 : A technical document supporting the Forest Service 2010 RPA Assessment. Newtown Square, PA : U.S. Dept. of Agriculture, Forest Service, Northern Research Station, 2013.

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Le, Floc'h E., dir. L' aridité : Une contrainte au développement : caractérisation, réponses biologiques, stratégies des sociétés. Paris : Editions de l'ORSTOM, 1992.

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Chapitres de livres sur le sujet "Aridità"

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Mainguet, Monique. « General Introduction ». Dans Aridity, 1–4. Berlin, Heidelberg : Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-662-03906-9_1.

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Mainguet, Monique. « The Spatial Framework, the Concepts of Aridity and Drought : the Soils and the Vegetation ». Dans Aridity, 5–78. Berlin, Heidelberg : Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-662-03906-9_2.

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Mainguet, Monique. « Resources vs. Hydrological and Aeolian Constraints ». Dans Aridity, 79–136. Berlin, Heidelberg : Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-662-03906-9_3.

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Mainguet, Monique. « Human Genius : The Search for Water and Its Management — Battle Against the Wind ». Dans Aridity, 137–201. Berlin, Heidelberg : Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-662-03906-9_4.

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Mainguet, Monique. « From Ingenuity to Decadence : Geohistory of an Actual Decline — Grounds for Hope ? » Dans Aridity, 203–67. Berlin, Heidelberg : Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-662-03906-9_5.

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Mainguet, Monique. « General Conclusion ». Dans Aridity, 269–74. Berlin, Heidelberg : Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-662-03906-9_6.

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Maliva, Robert, et Thomas Missimer. « Aridity and Drought ». Dans Arid Lands Water Evaluation and Management, 21–39. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-29104-3_2.

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Broccoli, Anthony J., et Syukuro Manabe. « Mountains and Midlatitude Aridity ». Dans Tectonic Uplift and Climate Change, 89–121. Boston, MA : Springer US, 1997. http://dx.doi.org/10.1007/978-1-4615-5935-1_5.

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Witter, Dan. « Aboriginal Dreaming and aridity ». Dans Animals of Arid Australia, 14–29. P.O. Box 20, Mosman NSW 2088, Australia : Royal Zoological Society of New South Wales, 2007. http://dx.doi.org/10.7882/fs.2007.038.

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Van Zinderen Bakker, E. M. « Aridity Along the Namibian Coast ». Dans Palaeoecology of Africa, 149–60. London : Routledge, 2022. http://dx.doi.org/10.1201/9780203744512-12.

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Actes de conférences sur le sujet "Aridità"

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PremKumar, R., S. ChennaKeasavan, N. Prethivik, R. Saravanan et S. SuriyaNarayan. « Solar Perigon with Aridity System ». Dans 2022 8th International Conference on Smart Structures and Systems (ICSSS). IEEE, 2022. http://dx.doi.org/10.1109/icsss54381.2022.9782160.

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Li, Zongmei, Zenxiang Zhang, Xiaoli Zhao et Xiao Wang. « Spatial Variability of the Aridity Index in China ». Dans 2012 2nd International Conference on Remote Sensing, Environment and Transportation Engineering (RSETE). IEEE, 2012. http://dx.doi.org/10.1109/rsete.2012.6260730.

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Besansky, Nora J. « Identification of SNPs associated with aridity tolerance inAnopheles gambiae ». Dans 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.95138.

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Tabor, Neil J. « ASSESSING ARIDITY ACROSS THE PERMIAN LANDS OF NORTH AMERICA ». Dans 54th Annual GSA South-Central Section Meeting 2020. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020sc-343285.

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De las Heras, J., D. Moya, F. R. López-Serrano, M. Eugenio et J. M. Espelta. « Aleppo pine regeneration after fire along an aridity gradient ». Dans FOREST FIRES 2008. Southampton, UK : WIT Press, 2008. http://dx.doi.org/10.2495/fiva080291.

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Andrade, C., et J. A. Corte-Real. « Preliminary assessment of aridity conditions in the Iberian Peninsula ». Dans INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS 2015 (ICNAAM 2015). Author(s), 2016. http://dx.doi.org/10.1063/1.4951826.

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Ilinskaya, Izida, Olga Bezuglova et Yuriy Litvinov. « ASSESSMENT OF THE ARIDIZATION OF THE SOUTH-EAST TERRITORY ROSTOV REGION IN DYNAMICS ». Dans Land Degradation and Desertification : Problems of Sustainable Land Management and Adaptation. LLC MAKS Press, 2020. http://dx.doi.org/10.29003/m1698.978-5-317-06490-7/152-155.

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Based on the analysis of a long series of observations of meteorological parameters, a comparative assessment of the indicators of aridity in the South-East of the Rostov region in terms of time has been carried out. A general tendency for the increase in the degree of climate aridization was established.
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Iliyasu, Abdullah M., Khaled A. Abuhasel, Mohammed A. Al-qodah et Ismail M. Arafat. « Aridity as a factor in estimating the lifespan of electronic systems ». Dans 2015 Annual Reliability and Maintainability Symposium (RAMS). IEEE, 2015. http://dx.doi.org/10.1109/rams.2015.7105147.

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Sun, Zhandong, Ni-Bin Chang, Christian Opp et Thomas Hennig. « Spatial and temporal characteristics of aridity conditions in Tarim Basin, China ». Dans Remote Sensing, sous la direction de Ulrich Michel et Daniel L. Civco. SPIE, 2010. http://dx.doi.org/10.1117/12.864956.

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Ana-Maria, Daniel. « CHANGES IN LAND COVER AND FOREST RESOURCES ALONG ARIDITY INDEXES : ECONOMIC PERSPECTIVES ». Dans 17th International Multidisciplinary Scientific GeoConference SGEM2017. Stef92 Technology, 2017. http://dx.doi.org/10.5593/sgem2017/32/s14.098.

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Rapports d'organisations sur le sujet "Aridità"

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Research Institute (IFPRI), International Food Policy. Influence of Aridity on Irrigation. Washington, DC : International Food Policy Research Institute, 2014. http://dx.doi.org/10.2499/9780896298460_23.

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Samach, Alon, Douglas Cook et Jaime Kigel. Molecular mechanisms of plant reproductive adaptation to aridity gradients. United States Department of Agriculture, janvier 2008. http://dx.doi.org/10.32747/2008.7696513.bard.

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Annual plants have developed a range of different mechanisms to avoid flowering (exposure of reproductive organs to the environment) under adverse environmental conditions. Seasonal environmental events such as gradual changes in day length and temperature affect the timing of transition to flowering in many annual and perennial plants. Research in Arabidopsis and additional species suggest that some environmental signals converge on transcriptional regulation of common floral integrators such as FLOWERING LOCUS T (FT). Here we studied environmental induction of flowering in the model legume Medicago truncatula. Similarly to Arabidopsis, the transition to flowering in M. truncatula is hastened by long photoperiods and long periods of vernalization (4°C for 2-3 weeks). Ecotypes collected in Israel retain a vernalization response even though winter temperatures are way above 4°C. Here we show that this species is also highly responsive (flowers earlier) to mild ambient temperatures up to 19°C simulating winter conditions in its natural habitat. Physiological experiments allowed us to time the transition to flowering due to low temperatures, and to compare it to vernalization. We have made use of natural variation, and induced mutants to identify key genes involved in this process, and we provide here data suggesting that an FT gene in M.truncatula is transcriptionally regulated by different environmental cues. Flowering time was found to be correlated with MtFTA and MtFTB expression levels. Mutation in the MtFTA gene showed a late flowering phenotype, while over-expressing MtFTA in Arabidopsis complemented the ft- phenotype. We found that combination of 4°C and 12°C resulted in a synergistic increase in MtFTB expression, while combining 4°C and long photoperiods caused a synergistic increase in MtFTA expression. These results suggest that the two vernalization temperatures work through distinct mechanisms. The early flowering kalil mutant expressed higher levels of MtFTA and not MtFTB suggesting that the KALIL protein represses MtFTA specifically. The desert ecotype Sde Boker flowers earlier in response to short treatments of 8-12oc vernalization and expresses higher levels of MtFTA. This suggests a possible mechanism this desert ecotype developed to flower as fast as possible and finish its growth cycle before the dry period. MtFTA and FT expression are induced by common environmental cues in each species, and expression is repressed under short days. Replacing FT with the MtFTA gene (including regulatory elements) caused high MtFTA expression and early flowering under short days suggesting that the mechanism used to repress flowering under short days has diversified between the two species.The circadian regulated gene, GIGANTEA (GI) encodes a unique protein in Arabidopsis that is involved in flowering mechanism. In this research we characterized how the expression of the M.truncatula GI ortholog is regulated by light and temperature in comparison to its regulation in Arabidopsis. In Arabidopsis GI was found to be involved in temperature compensation to the clock. In addition, GI was found to be involved in mediating the effect of temperature on flowering time. We tested the influence of cold temperature on the MtGI gene in M.truncatula and found correlation between MtGI levels and extended periods of 12°C treatment. MtGI elevation that was found mostly after plants were removed from the cold influence preceded the induction of MtFT expression. This data suggests that MtGI might be involved in 12°C cold perception with respect to flowering in M.truncatula. GI seems to integrate diverse environmental inputs and translates them to the proper physiological and developmental outputs, acting through several different pathways. These research enabled to correlate between temperature and circadian clock in M.truncatula and achieved a better understanding of the flowering mechanism of this species.
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Greenfield, Eric J., et David J. Nowak. Tree cover and aridity projections to 2060 : a technical document supporting the Forest Service 2010 RPA assessment. Newtown Square, PA : U.S. Department of Agriculture, Forest Service, Northern Research Station, 2013. http://dx.doi.org/10.2737/nrs-gtr-125.

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Weissinger, Rebecca. Evaluation of hanging-garden endemic-plant monitoring at Southeast Utah Group national parks, 2013–2020. Sous la direction de Alice Wondrak Biel. National Park Service, octobre 2022. http://dx.doi.org/10.36967/2294868.

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Hanging gardens are the most common type of spring at Arches National Park (NP) and Natural Bridges National Monument (NM). They are also present at Canyonlands National Park, but hanging gardens are rare off the Colorado Plateau. Their cliffside setting provides stable access to water without flood disturbance. This combination provides unique habitat that is rich in endemic plant species. The diffuse, seeping emergence of water makes measuring springflow impossible at most sites. Park managers have an interest in monitoring hanging gardens—especially as the climate warms and aridity and water demand both increase. The Northern Colorado Plateau Net-work (NCPN) proposed methods for monitoring seven perennial endemic-plant species at hanging gardens as indicators of spring health and proxies for water availability. Because hanging gardens occur on bedrock outcrops, systematic or random sampling was not possible due to safety concerns and potential resource damage on steep, wet slopes. Examining eight years (2013–2020) of data, this report evaluates the suitability of endemic-plant count data at hanging gardens as a monitoring indicator. It also provides our first evaluation of status and trends at NCPN hanging gardens. The seven species included in monitoring were Rydberg’s thistle (Cirsium rydbergii), Kachina daisy (Erigeron kachinensis), alcove death camas (Zigadenus vaginatus), alcove bog orchid (Habenaria zothecina), cave primrose (Primula specuicola), alcove columbine (Aquilegia micrantha), and Eastwood’s monkeyflower (Mimulus eastwoodiae). Six of the seven species were found at each park. Up to 500 individuals of each species were counted at 42 hanging gardens in Arches NP, 14 hanging gardens in Natural Bridges NM, and 3 hanging gardens in Canyonlands NP. Larger populations were divided into count classes of 501–1,000, 1,001–10,000, and more than 10,000 individuals. Counts from two independent observers and from back-to-back years of sampling were compared for repeatability. Repeatability in count classes was less than 50% for Kachina daisy and Eastwood’s monkeyflower, which both propagate vegetatively via ramets and/or stolons. Repeatability was greater than 90% for only one species, Rydberg’s thistle. The remaining species were categorized in different classes between 15–40% of the time. Independent-observer comparisons were only available for 6.6% of the dataset, but these observations suggested that (1) observer bias was present and (2) the observer with more experience working in hanging gardens generally had higher counts than the observer with less experience in this system. Although repeatability was variable, it was within the range reported by other studies for most species. The NCPN, in discussion with park staff, has elected to make some modifications to the protocol but will continue using endemic plant counts as an indicator of hanging-garden health to maintain a biological variable as a complement to our physical-response data. This is due to their high value to park biodiversity and the difficulty of developing a more robust approach to monitoring in these sites. Endemic-plant monitoring will continue for the five species with the highest repeatability during pilot monitoring and will focus on detecting changes in smaller populations. Most hanging gardens have more than one endemic species present, so several populations can be tracked at each site. Our period of record is relatively brief, and the distribution of endemic-plant populations in different count classes at these sites has not yet shown any statistical trends over time. Be-cause of the large count classes, our methods are more sensitive to showing change in smaller populations (fewer than 500 individuals). Small populations are also of greatest concern to park managers because of their vulnerability to declines or extirpation due to drought. Over-all, more sites had endemic-plant populations of fewer than 100 individuals at the end...
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