Integrity and isolation of Costa Rica's national parks and biological reserves: examining the dynamics of land-cover change   总被引：1，自引：0，他引：1  

G. Arturo Sánchez-Azofeifa  Gretchen C. Daily  Christopher Busch 《Biological conservation》2003,109(1):123-135

The transformation and degradation of tropical forest is thought to be the primary driving force in the loss of biodiversity worldwide. Developing countries are trying to counter act this massive lost of biodiversity by implementing national parks and biological reserves. Costa Rica is no exception to this rule. National development strategies in Costa Rica, since the early 1970s, have involved the creation of several National Parks and Biological Reserves. This has led to monitoring the integrity of and interactions between these protected areas. Key questions include: “Are these areas' boundaries respected?”; “Do they create a functioning network?”; and “Are they effective conservation tools?”. This paper quantifies deforestation and secondary growth trends within and around protected areas between 1960 and 1997. We find that inside of national parks and biological reserves, deforestation rates were negligible. For areas outside of National Parks and Biological reserves we report that for 1-km buffer zones around such protected areas, there is a net forest gain for the 1987/1997 time period. Thus, it appears that to this point the boundaries of protected areas are respected. However, in the 10-km buffer zones we find significant forest loss for all study periods. This suggests that increasing isolation of protected areas may prevent them from functioning as an effective network.  相似文献   

Behavior of Metals Under Different Seasonal Conditions: Effects on the Quality of a Mexico–USA Border River     

Agustín Gómez-Alvarez  Diana Meza-Figueroa  Jesús L. Valenzuela-García  Arturo I. Villalba-Atondo  Jorge Ramírez-Hernández 《Water, air, and soil pollution》2014,225(10):1-13

Spatial and seasonal mobilization trends of metals in surface water were evaluated in the US–Mexico San Pedro River (SPR). Water samples were collected at five sampling stations for the analysis of dissolved oxygen, pH, electric conductivity, sulfates, and metals (Cd, Cu, Fe, Mn, Pb, and Zn). Quality of the water was characterized through Ecological Criteria of Water Quality (ECWQ) established in Mexico and Water Quality Criteria (Environmental Protection Agency (EPA)). High total metal concentrations were detected as follows: Fe?>?Cu?>?Mn?>?Zn?>?Pb?>?Cd. Metal concentrations were slightly higher in dry season than in rainy season: Cd (below detection limit (BDL)–0.21 mg L^?1), Cu (BDL–13 mg L^?1), Fe (0.16–345 mg L^?1), Mn (0.12–52 mg L^?1), Pb (BDL–0.48 mg L^?1), and Zn (0.03–17.8 mg L^?1). Low pH and dissolved oxygen values as well as high sulfate content were detected in both seasons. High values of metals (Cd, Cu, Fe, Mn, Pb, Zn) were detected at station E1 representing pollution source, as well as at stations E2 (Cd, Cu, Fe, Mn), E3 (Fe, Mn, Pb), and E4 and E5 (Fe, Mn). Detected concentrations exceeded maximum permissible established in ECWQ and Water Quality Criteria (EPA). Efflorescence salts on sediments in the dry season could increase levels of metals in water column. This study provides valuable information on the potential mobility of metals in surface water of SPR located in an arid environment where transport processes are strongly linked to climate. The information derived from this study should help the regional and national authorities to address present environmental regulations.  相似文献   

Accumulation and erosion of Mars' south polar layered deposits     

Seu R  Phillips RJ  Alberti G  Biccari D  Bonaventura F  Bortone M  Calabrese D  Campbell BA  Cartacci M  Carter LM  Catallo C  Croce A  Croci R  Cutigni M  Di Placido A  Dinardo S  Federico C  Flamini E  Fois F  Frigeri A  Fuga O  Giacomoni E  Gim Y  Guelfi M  Holt JW  Kofman W  Leuschen CJ  Marinangeli L  Marras P  Masdea A  Mattei S  Mecozzi R  Milkovich SM  Morlupi A  Mouginot J  Orosei R  Papa C  Paternò T  Persi del Marmo P  Pettinelli E  Pica G  Picardi G  Plaut JJ  Provenziani M  Putzig NE  Russo F  Safaeinili A  Salzillo G 《Science (New York, N.Y.)》2007,317(5845):1715-1718

Mars' polar regions are covered with ice-rich layered deposits that potentially contain a record of climate variations. The sounding radar SHARAD on the Mars Reconnaissance Orbiter mapped detailed subsurface stratigraphy in the Promethei Lingula region of the south polar plateau, Planum Australe. Radar reflections interpreted as layers are correlated across adjacent orbits and are continuous for up to 150 kilometers along spacecraft orbital tracks. The reflectors are often separated into discrete reflector sequences, and strong echoes are seen as deep as 1 kilometer. In some cases, the sequences are dipping with respect to each other, suggesting an interdepositional period of erosion. In Australe Sulci, layers are exhumed, indicating recent erosion.  相似文献   

Determination of esters of fatty acids with low molecular weight alcohols in olive oils     

Pérez-Camino MC  Moreda W  Mateos R  Cert A 《Journal of agricultural and food chemistry》2002,50(16):4721-4725

A simple and precise analytical method was developed for the simultaneous determination of squalene and methyl, ethyl, propyl, and butyl esters of fatty acids present in olive and olive pomace oils. A fraction containing squalene and fatty acid alkyl esters was isolated from the oil by solid phase extraction on silica gel cartridges and quantitatively analyzed by gas chromatography. A modification of the procedure allowed the isolation of squalene and esters separately. Repeatability and recovery of the method were good. The method was applied to extra and lampant virgin olive oil categories and also to oils obtained from olive pomace by second centrifugation and solvent extraction. Extra virgin olive oils contained low amounts of fatty acid methyl and ethyl esters, while oils obtained from altered olive or olive pomace showed high concentrations of fatty acid alkyl esters, mainly ethyl esters. Correlation between oil acidity and ethyl esters concentration was poor.  相似文献   

Electrophysiological and behavioural responses of Pityophthorus pubescens (Coleoptera: Scolytinae) to (E,E)‐α‐farnesene, (R)‐(+)‐limonene and (S)‐(−)‐verbenone in Pinus radiata (Pinaceae) stands in northern Spain     

Sergio López  Carmen Quero  Juan Carlos Iturrondobeitia  Ángel Guerrero  Arturo Goldarazena 《Pest management science》2013,69(1):40-47

BACKGROUND: Some twig beetles in the genus Pityophthorus (Coleoptera: Scolytinae) may vector pitch canker disease Fusarium circinatum (Niremberg & O'Donnell) of Pinus spp. (Pinaceae). Because Pityophthorus pubescens (Marsh.) has been found to be associated with F. circinatum in the Basque Country (northern Spain), various experiments were conducted to assess the beetle's behavioural responses to (E, E)‐α‐farnesene, (R)‐(+)‐limonene and (S)‐(?)‐verbenone to develop a potential inhibitor to host attraction. These experiments comprise electroantennographic and double‐choice olfactometer tests, as well as field assays in Pinus radiata D. Don stands. RESULTS: Both sexes of P. pubescens showed similar electroantennographic responses to different doses (from 1 ng to 1 µg in decadic steps) of each individual compound, with depolarisations to (S)‐(‐)‐verbenone (100 ng) being similar to those of the aggregation pheromone (+)‐trans‐pityol. In olfactometer assays, both sexes were significantly attracted to (+)‐trans‐pityol, but the attraction was reduced when increasing amounts of the chemicals were added to the pheromone. Particularly relevant was the repellent effect induced by (S)‐(?)‐verbenone at 1 ng dose and higher. In the field, (E, E)‐α‐farnesene, (R)‐(+)‐limonene and (S)‐(?)‐verbenone reduced significantly the number of beetles attracted to (+)‐trans‐pityol and racemic trans‐pityol, with (S)‐(?)‐verbenone being the most effective. CONCLUSIONS: (S)‐(?)‐Verbenone showed an interesting potential for use in the protection of P. radiata stands. A potentially effective strategy, which could be implemented in further, more in‐depth studies, could involve the use of this semiochemical as repellent and (+)‐trans‐pityol‐baited traps as attractant in a ‘push‐pull’ strategy. Copyright © 2012 Society of Chemical Industry  相似文献   

Seasonal Variation in Heat Fluxes, Predicted Emissions of Malodorants, and Wastewater Quality of an Anaerobic Swine Waste Lagoon     

John H. Loughrin  Arturo I. Quintanar  Kim L. Cook  Nanh C. Lovanh  Rezaul Mahmood  Evi Becerra-Acosta 《Water, air, and soil pollution》2012,223(7):3611-3618

The concentrations of p-cresol above a wastewater lagoon were modeled from February through June based on equations developed in a previous study. Using this model, in which p-cresol concentrations were calculated based on lagoon evaporation and net available radiation at the lagoon surface, predicted p-cresol concentrations were highest during the months of March and April and declined to very low levels thereafter. This was in accordance with observed emission patterns in the previous study. In the same period during which predicted emissions increased, wastewater concentrations of malodorants decreased. While other indicators of wastewater quality such as ammonium and chemical oxygen demand (COD) also decreased in concentration, the magnitude of their improvement was not as high as for the malodorants. There were no pronounced differences in bacterial populations between the cool and warm seasons based on molecular quantification of genes targeting total cells, Bacteroides, Clostridia, and methanogens. While the improvement in the concentrations of wastewater malodorants may be due to catabolism by lagoon bacteria, our findings indicate that evaporative losses that occurred as the lagoon warmed may also play a strong role.  相似文献   

Seed viability and effect of temperature on germination of Agave angustifolia subsp. tequilana and A. mapisaga; two useful Agave species     

Hugo Magdaleno Ramírez Tobías  Reyna Niño Vázquez  Juan Rogelio Aguirre Rivera  Joel Flores  José Arturo De-Nova Vázquez  Ramón Jarquin Gálvez 《Genetic Resources and Crop Evolution》2016,63(5):881-888

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Tropical dry forest succession and the contribution of lianas to wood area index (WAI)     

G. Arturo Sánchez-Azofeifa  Margaret Kalácska  Mario Marcos do Espírito-Santo  G. Wilson Fernandes  Stefan Schnitzer 《Forest Ecology and Management》2009

The transmission and interception of light through the canopy is an important indicator of forest productivity in tropical forest ecosystems, and the amount of light that eventually reaches the forest floor is influenced by its interactions with leaves, branches, fruits, and flowers among many different canopy elements. While most studies of forest canopy light interception focus on leaf area index (LAI), very few studies have examined wood area index (WAI), which may account for a substantial component of light interception in tropical forests. The influence of lianas on the interception of light and their overall contribution to WAI is a potentially important factor, but it is generally overlooked because of its difficulty to assess. In this paper we evaluate the relative contribution that lianas have to the overall WAI and canopy openness as function of successional stage via a latitudinal comparison of sites across the Americas (Mexico, Costa Rica and Brazil). Our results suggest that lianas significantly increase WAI and decreases canopy openness. However, lianas were absent at all of our study sites where canopy openness exceeded 60%. Our data are the first to explicitly document the role of lianas in the estimation of WAI and, overall, they will contribute to better estimations of ecosystem level LAI in tropical environments, where there is a lack of data on WAI.  相似文献   

Land cover and conservation in the area of influence of the Chamela-Cuixmala Biosphere Reserve,Mexico     

G. Arturo Sánchez-Azofeifa  Mauricio Quesada  Pablo Cuevas-Reyes  Alicia Castillo  Gumersindo Sánchez-Montoya 《Forest Ecology and Management》2009

Tropical deforestation and habitat fragmentation in areas around conservation areas have been an important element for discussion in the conservation and policy-making community. In this paper, we evaluate land cover change processes around one of the most important tropical dry forest reserves in the Americas: the Chamela-Cuixmala Biosphere Reserve, Mexico. The analysis is conducted at three scales: regional scale (coast of the State of Jalisco), proximity to the reserve (via a 30-km buffer zone analysis), and inside the Biosphere Reserve. The proximity analysis is complemented by a unique data set that represents the extent and boundaries of Ejidos (local land management units) in the region. Results indicate that areas surrounding the reserve have low deforestation, with Ejidos and buffer areas having more forest cover as they get closer to the reserve. The nature of this important phenomenon is discussed in the context of the socio-economic conditions of the local communities. Our work suggests that the creation of a network of “Ejidos’ Conservation Areas”, in the context of an approach that will recognize payments for environmental services provided to local communities, could contribute to the conservation and maintenance of the rich biodiversity in a region that has one of the highest levels of endemism in the world.  相似文献   

Succession and management of tropical dry forests in the Americas: Review and new perspectives     

Mauricio Quesada  G. Arturo Sanchez-Azofeifa  Mariana Alvarez-Añorve  Kathryn E. Stoner  Luis Avila-Cabadilla  Julio Calvo-Alvarado  Alicia Castillo  Mario M. Espírito-Santo  Marcilio Fagundes  Geraldo W. Fernandes  John Gamon  Martha Lopezaraiza-Mikel  Deborah Lawrence  Leonor Patricia Cerdeira Morellato  Jennifer S. Powers  Frederico de S. Neves  Victor Rosas-Guerrero  Roberto Sayago  Gumersindo Sanchez-Montoya 《Forest Ecology and Management》2009

Understanding tropical forest succession is critical for the development of tropical forest conservation strategies worldwide, given that tropical secondary forests can be considered the forests of the future. Tropical dry forests (TDF) are among the most threatened tropical ecosystems, there are more secondary forests and forest restoration efforts that require a better understanding of successional processes. The main goal of this synthesis for this special issue on the ecology and management of tropical dry forests in the Americas is to present a summarized review of the current knowledge of the ecology and management implications associated to TDF succession. We explore specific issues associated to tropical dry forest succession with emphasis on the use of chronosequences, plant diversity and composition, plant phenology and remote sensing, pollination, and animal–plant interactions; all under the integrating umbrella of ecosystem succession. We also emphasize the need to conduct socio-ecological research to understand changes in land-use history and its effects on succession and forest regeneration of TDF. We close this paper with some thoughts and ideas associated with the strong need for an integrating dimension not considered until today: the role of cyberinfrastructure and eco-informatics as a tool to support sound conservation, management and understanding of TDF in the Americas.  相似文献