排序方式: 共有11条查询结果,搜索用时 15 毫秒
1.
Fernando Antonio Rosete Vergés Alejandro Velázquez Gerardo Bocco Ileana Espejel 《Regional Environmental Change》2014,14(4):1315-1328
Land use and cover changes trigger multi-factorial responses with tangible and intangible effects. Driving forces governing changes are scale-, place- and time-dependent; because of their complexity, a multi-scalar analysis is required to determine conjoint causation. Studies using multi-scalar approach in semiarid scrubland ecosystems are scanty. This paper investigates land use changes on the largest semiarid scrubland ecosystem of Mexico, the Baja California Peninsula, using a multi-scalar analysis approach. It further provides insight into the likely underlying causes for land use trends. Multi-temporal databases were compiled for 1978, 1990, 2000 and 2003 from various sources; population was projected for the same years. Land cover processes were validated through intensive fieldwork. Map overlapping with the aid of geographic information systems allowed computation of land cover transformation rates. New algorithms were developed to better understand land cover trends. Multi-variate analysis was also performed to provide a synthetic statistical overview. Results showed that land cover change occurred at different times, at variable scales, due to distinct drivers. As a consequence, the current regional scenario has been shaped by distinguishable socio-economic changes. The semiarid scrubland ecosystems in the Baja California Peninsula experienced contrasting trends detectable only at site and local scales. Regionally, the replacement of original vegetation (scrubland) for other land cover category is following trends similar to those in the rest of Mexico and most semiarid ecosystems worldwide. These findings support the hypothesis that land use and cover changes must be analyzed at different times and scales to deeply understand underlying forces. 相似文献
2.
Alejandro Espinoza-Tenorio Gabriela Montaño-Moctezuma Ileana Espejel 《Environmental management》2010,45(4):739-750
The Gulf of California Biosphere Reserve (UGC&CRDBR) is a Marine Protected Area that was established in 1993 with the aim
of preserving biodiversity and remediating environmental impacts. Because remaining vigilant is hard and because regulatory
measures are difficult to enforce, harvesting has been allowed to diminish poaching. Useful management strategies have not
been implemented, however, and conflicts remain between conservation legislation and the fisheries. We developed a transdisciplinary
methodological scheme (pressure-state-response, loop analysis, and Geographic Information System) that includes both protected
species and fisheries modeled together in a spatially represented marine ecosystem. We analyzed the response of this marine
ecosystem supposing that conservation strategies were successful and that the abundance of protected species had increased.
The final aim of this study was to identify ecosystem-level management alternatives capable of diminishing the conflict between
conservation measures and fisheries. This methodological integration aimed to understand the functioning of the UGC&CRDBR
community as well as to identify implications of conservation strategies such as the recovery of protected species. Our results
suggest research hypotheses related to key species that should be protected within the ecosystem, and they point out the importance
of considering spatial management strategies. Counterintuitive findings underline the importance of understanding how the
community responds to disturbances and the effect of indirect pathways on the abundance of ecosystem constituents. Insights
from this research are valuable in defining policies in marine reserves where fisheries and protected species coexist. 相似文献
3.
Tania Pérez-Pérez Gleyce Teixeira Correi Wu Hong Kwong Ileana Pereda-Reyes Deny Oliva-Merencio Marcelo Zaiat 《环境科学学报(英文版)》2017,29(4):224-230
As a support material, zeolite can be used to promote the granulation process due to its high settable property and the ability to retain biomass on its surface. The present paper reports on the influence of zeolite addition on the hydrodynamic behavior of an expanded granular sludge bed reactor (EGSB). Different models were applied to fit the flow pattern and to compare EGSB hydrodynamic performance with and without the addition of zeolite. The experimental data fit the tanks in a series model for zeolite bed height of 5 cm and upflow velocity of 6 m/hr. Higher axial dispersion degree (D/uL) was obtained at lower heights of zeolite. The real hydraulic retention time (HRTr) was increased with both increased zeolite bed height and increased upflow velocity. The short-circuit results for 5 cm of zeolite bed and 6, 8 and 10 m/hr upflow velocity were 0.3, 0.24 and 0.19 respectively, demonstrating the feasibility of using zeolite for a proper hydrodynamic environment to operate the EGSB reactor. The presence of zeolite resulted in the higher percentage values of dead zones, ranging from 12% to 24%. Zeolite addition exerted a positive effect on the hydrodynamics pattern for this technology being advantageous for the anaerobic process because of its possible contribution to better biofilm agglomeration, granule formation and substrate-microorganism contact. 相似文献
4.
Martínez Jaxiry Shamara Barroso González Antonia Sandoval López Mónica Cerro Ayala Fabricio Espejel Mijangos Jesús Cárdenas de Jesús Treviño Reséndez José Vöng Yunny Meas Rocha Juan Manríquez Bustos Erika Bustos 《Environmental science and pollution research international》2022,29(28):42130-42145
Environmental Science and Pollution Research - One of the most widely used antibiotics is amoxicillin (AMX), which is the most widely used in humans and animals, but it is discharged metabolically... 相似文献
5.
Antonio E. Alegria Sheila Sanchez Pedro Sanchez-Cruz Ileana Nieves Nadya G. Cruz Marina Gordaliza 《毒物与环境化学》2013,95(2):237-245
Novel terpenylnaphthoquinones were found to enhance the rate of oxygen consumption in the presence of NADH/NADH dehydrogenase in 1?:?1?v/v mixtures of 40?mM phosphate buffer (pH 7.4) and DMSO. Initial rates of oxygen consumption increase with an increase in the half-wave reduction potentials of the quinones. The amounts of spin trapped methyl radicals in the presence of DMSO, produced through the Haber–Weiss reaction of the oxygen consumption process, and of the corresponding semiquinones, generated under anaerobic conditions, also correlate with the quinone redox potential. Since this enzymatic system is found in mitochondria, a possible pathway in the cytotoxic activity of these terpenylnaphthoquinones could be the interference or inhibition of mitochondrial respiration by NADH depletion or by mitochondrial degradation due to reactive oxygen species generation. 相似文献
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Cira Marisol Echeverria-Palencia Cristina M. Callejas Ileana Jimenez Karina Herrera Rafael Hung Wei-Cheng Colima Nicolas Schmidt Amanda Jay Jennifer A. 《Environmental science and pollution research international》2021,28(32):43507-43514
Environmental Science and Pollution Research - The dissemination of antibiotic resistance genes (ARGs) in the environment contributes to the global rise in antibiotic resistant infections.... 相似文献
8.
This paper presents the main results of two studies of contrasting natural and man-induced conditions along the Pacific coast
of Baja California (Mexico), based on the assumption that ecological insight can be obtained from man-induced modifications
insofar as relevant activities are explicitly addressed as parts of the systems under study. The study is concerned with a
fragmented coastal succulent-sage scrub and showed that several patches of different size and age may harbor as many species
as non-fragmented areas, and that 83% of the original species assemblage persisted in the fragments, in which the invasion
by opportunistic exotic species may not progress beyond certain limits. The study of dune-backed and urban-backed beaches
showed a significantly greater abundance of the Snowy Plover (Charadrius alexandrinus) at the dune-backed beach, where a much more active back-shore feeding of adult birds and the only evidences of breeding
occurred. Both studies refer to landscape features of regional concern and its results may be used in conservation management.
The results on fragmented coastal succulentsage scrub may encourage alternative urban designs that keep patches of the original
landscape, thus meeting existing requirements of low density urban development for most of the coastal succulent-sage scrub
area. The evidence presented on the negative effects of dune destruction on the abundance, feeding and reproductive performance
of a threatened bird species has a bearing on the topic of biodiversity management. It may also contribute to the conservation
of the coastal dunes system. 相似文献
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10.
Radu Lacatusu Corneliu Rautal Constantin Grigore Stelian Cârsteal Ileana Ghelasel 《Environmental geochemistry and health》1993,15(1):3-13
Haematuria-inducing areas in the northern and central parts of the Eastern Carpathian Mountains are characterised by the mesozoic-crystalline, neogene eruptive and transcarpathian flysch zones. The rocks have high concentrations of some metals and radioactive elements, some of them bearing polymetallic sulphides. The soils are strongly or moderately acid and oligomesobasic. They have a deficiency of soluble phosphorus and molybdenum, but up to 4.9 times the background content of metallic elements in non-affected zones. The waters have a pH around 7, a low content of salts (0.09–0.62 g L–1), but metal levels in excess of 10 times that of the background level. Pasture vegetation has a low nutritional value, and includes up to 12% of poisonous plant species. It is characterised by low total concentrations of P, Mo, N and K, and high total concentrations of metallic trace elements, including high values of Zn and excessive values of Fe, Mn, Pb, Cr, Ni, Cd and Al. Besides clinical symptoms specific to haematuria, sick animals have abnormal blood and urinary compositions and specific morphopathological features. High concentrations of metallic elements were detected in renal calculi. The correlation of the geochemical and biogeochemical features of the haematuria-inducing areas, together with the results of the epizootological, clinical, paraclinical and morphopathological research emphasises that chronic cattle haematuria is a disease with numerous causes, but is primarily a biogeochemical problem in the area studied, making it an ecosystem disease.To whom correspondence should be addressed. 相似文献