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1.
Suescún Diego Villegas Juan Camilo León Juan Diego Flórez Claudia P. García-Leoz Vanessa Correa-Londoño Guillermo A. 《Regional Environmental Change》2017,17(3):827-839
Regional Environmental Change - Mountain ecosystems provide key services to a large portion of the population in the tropics. However, they are particularly vulnerable to regional environmental... 相似文献
2.
Llano-Sotelo JM Alcaraz-Melendez L Castellanos Villegas AE 《Journal of environmental biology / Academy of Environmental Biology, India》2010,31(4):497-502
In order to evaluate their responses to drought, we determined the photosynthetic activity water potential, stomatal conductance, transpiration, water use efficiency photosynthetic photon flux density and leaf temperature of Paulownia imperialis, P. fortunei and P. elongata in three different soil moisture conditions in the field. Our results showed that P. imperialis had greater photosynthesis (8.86 micromol CO2 m(-2) s(-1)) and instantaneous water use efficiency (0.79 micromol CO2 mmol H2O(-1)) than either P. elongata (8.20 micromol CO2 m(-2) s(-1) and 0.71 micromol CO2 mmol H2O(-1)) or P. fortunei (3.26 micromol CO2 m(-2) s(-1) and 0.07 micromol CO2 mmol H2O(-1)). The rapid growth of Paulownia did not appear to be correlated with photosynthetic rates. Paulownia fortunei showed more transpiration (48.78 mmol H2O m(-2) s(-1)) and stomatal conductance (840 mmol m(-2) s(-1)) than P. imperialis (20 mmol H2O m(-2) s(-1) and 540 mmol m(-2) s(-1)) and P. elongata (20 mmol H2O m(-2) s(-1) and 410 mmol m(-2) s(-1)), which allowed these two Paulownia species to increase their tolerance to low soil moisture, and maintain higher water use efficiency under these conditions. According to our physiological gas exchange field tests, Paulownia imperialis does appear to be capable of successful growth in semiarid zones. 相似文献
3.
Alfredo Villegas Camil 《生态毒理学报》2001,23(4):52-53
墨西哥城市中心区的空气质量,主要取决于排放的污染物的体积和危险性、它们的化学性质和决定它们在大气中分散、转化和消除的气象动力学.而排放量又受到各种因素的影响,最重要因素是:车辆技术、工业和公共设施的技术和产量、城市结构(区域、密度和多样性)、运输模式的混合以及出行的总里程. 相似文献
4.
García-Leoz Vanessa Villegas Juan Camilo Suescún Diego Flórez Claudia P. Merino-Martín Luis Betancur Teresita León Juan Diego 《Regional Environmental Change》2018,18(4):1117-1129
Regional Environmental Change - Vegetation actively affects different components of the water budget in multiple spatial and temporal scales. Changes in vegetation cover and structure—such as... 相似文献
5.
Marta I. Sánchez Andy J. Green Francisco Amat Eloy M. Castellanos 《Marine Biology》2007,151(4):1407-1415
Waterbirds are known to disperse invertebrate propagules that survive gut passage, but there is very little information about
how the probability of dispersal changes at different times of the annual cycle when birds move in different directions, or
how it is affected by changes in diet. We studied internal transport of brine shrimp Artemia cysts by migratory waders in the Odiel saltworks in south-west Spain. Viable cysts of parthenogenetic Artemia were abundant in the faeces and regurgitated pellets of redshank Tringa totanus, pellets of spotted redshank T. erythropus, and faeces of black-tailed godwit Limosa limosa during spring and/or autumn migrations in 2001–2002, but were not recorded during winter. Godwits did not produce pellets,
and spotted redshank faeces were not sampled. Significant correlations between the number of cysts in a pellet or faecal sample
and the proportion of that sample constituted by Artemia adults suggested that most cysts were ingested while in the ovisacs of gravid females. The proportion of cysts destroyed
during digestion increased when accompanied by harder food items or grit, and when fewer cysts were ingested. The median number
of intact cysts was higher in redshank faeces than in their pellets, but cysts extracted from pellets were more likely to
hatch. A higher proportion of redshank pellets contained Artemia cysts in spring than in autumn, but more redshank migrated through the area in autumn. Significantly fewer cysts were recorded
in redshank pellets in winter than in spring or autumn. Our results confirm that there is potential for long-distance dispersal
of Artemia cysts via waders during both northwards (spring) and southwards (autumn) migrations. 相似文献
6.
Eakin H Bojórquez-Tapia LA Monterde Diaz R Castellanos E Haggar J 《Environmental management》2011,47(3):352-367
Communities who rely directly on the natural environment for their survival typically have developed risk management strategies
to enable them to avoid dangerous thresholds of change to their livelihoods. Development policy appropriate for natural resource-based
communities requires an understanding of the primary drivers of social-ecological change, the ways in which affected households
autonomously respond to such drivers, and the appropriate avenues for intervention to reduce vulnerability. Coffee has been,
and still remains, one of the most important commodities of the Mesoamerican region, and hundreds of thousands of smallholder
households in the region are dependent in some way on the coffee industry for their livelihood stability. We used the Analytical
Network Process to synthesize expert knowledge on the primary drivers of livelihood change in the region as well as the most
common household strategies and associated capacities necessary for effective response. The assessment identified both gradual
systemic processes as well as specific environmental and market shocks as significant drivers of livelihood change across
the region. Agronomic adjustments and new forms of social organization were among the more significant responses of farmers
to these changes. The assessment indicates that public interventions in support of adaptation should focus on enhancing farmers’
access to market and technical information and finance, as well as on increasing the viability of farmers’ organizations and
cooperatives. 相似文献
7.
P.?W.?ShawEmail author A.?I.?Arkhipkin G.?J.?Adcock W.?J.?Burnett G.?R.?Carvalho J.?N.?Scherbich P.?A.?Villegas 《Marine Biology》2004,144(5):961-970
The Patagonian squid, Loligo gahi DOrbigny, has been described as having temporally and spatially identifiable spawning aggregations. Variation at six microsatellite loci was used to assess whether seasonal and geographical spawning groups around the Falkland Islands represent distinct sub-populations. Genetic variation at these loci is high in this species (mean expected heterozygosity=0.87; mean number of alleles=14.7). No evidence of significantly different allele frequencies was found, either between samples from putative spawning cohorts or geographical areas, indicating that L.gahi around the Falkland Islands comprise a single genetically homogeneous population. Age structure analysis of samples (from statolith growth increments) indicated substantial spread in hatching dates among individuals of similar size and maturity status, suggesting the potential for extensive interbreeding between seasonal cohorts. A sample of L.gahi from the SE Pacific (Peru) displayed distinctly different gene frequencies (and allele size distribution at one locus) from SW Atlantic samples, supporting the suggestion that SE Pacific and SW Atlantic populations may represent distinct subspecies.Contributed by J.P. Thorpe, Port Erin 相似文献
8.
Gonzalez-Ocampo H Romero-Schmidt H Serrano-Pinto V Arguelles C Salinas F Rodríguez A Castellanos A Ortega-Rubio A 《Journal of environmental biology / Academy of Environmental Biology, India》2004,25(1):27-38
Aquaculture offers a major opportunity for the economic development of Baja California Sur (BCS), Mexico. The severely limited freshwater supply and the geographic isolation of the state place limits on other productive activities. Despite the aridity, the natural vegetation of BCS is diverse and structurally complex with a high percentage (20%) of endemic species. In this work we compare the environmental impacts produced by two kinds of aquaculture systems: coastal ponds vs. inland ponds. Construction and operation of coastal ponds does not require destruction of the natural vegetation and, as is true for inland ponds. Coastal ponds are also compatible with conservation of mangroves, sea grasses and sensitive habitats for fish and mollusks. To reduce the negative impacts of aquaculture and to protect the vegetation of Baja California Sur, we recommend the use of coastal ponds for shrimp production. 相似文献
9.
Pitchamani Godwyn-Paulson Ponniah Jonathan Muthuswamy Rodríguez-Espinosa Pedro Francisco Roy Priyadarsi Debajyoti Sánchez-Núñez Juan Manuel Villegas Lorena Elizabeth Campos Rodríguez-González Francisco Márquez-Herrera Ciro Eliseo 《Environmental science and pollution research international》2022,29(41):61698-61710
Environmental Science and Pollution Research - The vertical distribution pattern and concentrations of elements (Fe, Al, Ca, Mg, Mn, Cr, Cu, Ni, Co, Pb, Zn, and As) in the estuarine and lagoon... 相似文献
10.
M. Fernanda Alvarez Hernán H. Benítez J. Camilo Villegas Cortés Néstor A. Gabellone M. Cristina Claps 《Chemistry and Ecology》2016,32(8):742-755
Polyphenols – products of organic-matter decomposition entering water bodies from autochthonous and especially allochthonous sources – affect primary producers, bacterioplankton, and zooplankton to consequently modify food webs. Cladocerans are widely used in research experiments because they constitute the most frequent prey of high-trophic-level organisms in the majority of lakes, and certain species symbolise the ecologic prototype of the generalist filter feeder. In our study area’s shallow lakes, cladocerans, though generally of low abundance, do attain significantly high biomasses. We accordingly evaluated the mortality of the cladoceran Daphnia menucoensis Paggi, 1996 exposed to different tannin concentrations along with the bacterial abundance. In two experiments D. menucoensis females exposed to high tannin concentrations reproduced inefficiently, exhibited high mortality, and manifested altered behaviour, such as reduced reflexes and diminished mobility. Though tannins apparently affected algal abundances, the cladoceran herbivory strongly reduced those numbers. Positive effects on bacteria, however, were not recorded. High-allochthonous-organic-matter-containing water bodies support trophic webs because bacterioplankton provide an alternative energetic base for the zooplankton, as possibly occurs in shallow lakes of the Salado-River basin, characterised by cyclic hydrologic periods alternating between draught and flooding and intensive land use. In conclusion, tannins diminish D. menucoensis’s survival, locomotion, and the capacity to respond to stimuli. 相似文献