Modeling species’ geographic distributions for preliminary conservation assessments: an implementation with the spiny pocket mice (Heteromys) of Ecuador     

Robert P. Anderson  Enrique Mart?&#x;nez-Meyer 《Biological conservation》2004,116(2):167-179

GIS-based modeling of a species’ environmental requirements using known occurrence records can provide estimates of its distribution for conservation assessments when other data are lacking. We used collection records, environmental variables, maps of land cover and protected areas, and the Genetic Algorithm for Rule-Set Prediction (GARP) to estimate the historical, current, and protected ranges of the spiny pocket mice present in Ecuador (Heteromys australis and H. teleus). The results suggest that ca. 52-63% of the distributional areas of H. australis in the country are intact, but suitable habitat in protected areas represents only approximately 11-13% of the species’ historical range there. The distribution of H. teleus has been much more reduced, with only ca. 13-19% of its historical distribution still forested and an estimated 2-3% intact and falling in protected areas. Our work highlights critical areas for future fieldwork and demonstrates an integrated approach to estimating a species’ current distribution for preliminary conservation assessments.  相似文献   

Mixed culture optimization for marigold flower ensilage via experimental design and response surface methodology   总被引：2，自引：0，他引：2  

Navarrete-Bolaños JL  Jiménez-Islas H  Botello-Alvarez E  Rico-Martínez R 《Journal of agricultural and food chemistry》2003,51(8):2206-2211

Endogenous microorganisms isolated from the marigold flower (Tagetes erecta) were studied to understand the events taking place during its ensilage. Studies of the cellulase enzymatic activity and the ensilage process were undertaken. In both studies, the use of approximate second-order models and multiple lineal regression, within the context of an experimental mixture design using the response surface methodology as optimization strategy, determined that the microorganisms Flavobacterium IIb, Acinetobacter anitratus, and Rhizopus nigricans are the most significant in marigold flower ensilage and exhibit high cellulase activity. A mixed culture comprised of 9.8% Flavobacterium IIb, 41% A. anitratus, and 49.2% R. nigricans used during ensilage resulted in an increased yield of total xanthophylls extracted of 24.94 g/kg of dry weight compared with 12.92 for the uninoculated control ensilage.  相似文献   

Do landscape and riverscape shape genetic patterns of the Neotropical otter,Lontra longicaudis,in eastern Mexico?     

Latorre-Cardenas  María Camila  Gutiérrez-Rodríguez  Carla  Rico  Yessica  Martínez-Meyer  Enrique 《Landscape Ecology》2021,36(1):69-87

Context

Functional connectivity of semiaquatic species is poorly studied despite that freshwater ecosystems are amongst the most threatened worldwide due to habitat deterioration. The Neotropical otter, Lontra longicaudis, is a threatened species that represents a good model to evaluate the effect of landscape-riverscape features on genetic structure and gene flow of freshwater species.

Objectives

We aimed to assess the spatial genetic structure of L. longicaudis and to evaluate the landscape-riverscape attributes that shape its genetic structure and gene flow at local sites (habitat patches) and between sites (landscape matrix).

Methods

We conducted the study in three basins located in Veracruz, Mexico, which have a high degree of ecosystem deterioration. We used a non-invasive genetic sampling and a landscape genetics individual-based approach to test the effect stream hierarchical structure, isolation-by-distance, and isolation-by-resistance on genetic structure and gene flow.

Results

We found genetic structure that corresponded to the latitudinal and altitudinal heterogeneity of the landscape and riverscape, as well as to the hierarchical structure of the streams. Open areas and steep slopes were the variables affecting genetic structure at local sites, whereas areas with suitable habitat conditions, higher ecosystem integrity and larger streams enhanced gene flow between sites.

Conclusions

The landscape-riverscape characteristics that maintain functional connectivity of L. longicaudis differed between the upper, middle, and lower basins. Our results have important implications for the conservation of the species, including the maintenance of larger suitable areas in Actopan and the necessity to improve connectivity in Jamapa, through the establishment of biological corridors.

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Canopy species composition drives seasonal soil characteristics in a Mediterranean riparian forest     

Pérez-Corona  María Esther  Pérez-Hernández  María del Carmen  Medina-Villar  Silvia  Andivia  Enrique  Bermúdez de Castro  Francisco 《European Journal of Forest Research》2021,140(5):1081-1093

European Journal of Forest Research - Mediterranean riparian ecosystems provide key ecosystem services, such as climate regulation, water quality, and flood protection. Forest degradation and...  相似文献   

Protein, carbohydrate, lipid and chlorophyll a content in Isochrysis aff. galbana (clone T-Iso) cultured with a low cost alternative to the f/2 medium     

Enrique Valenzuela-Espinoza  Roberto Milln-Núez  Filiberto Núez-Cebrero 《Aquacultural Engineering》2002,25(4):291-216

Growth, proximate composition and chlorophyll a content was estimated in static cultures of Isochrysis aff. galbana (clone T-Iso) to compare the quality and quantity of the biomass produced with an agricultural fertilizer medium versus f/2 medium. Culture of microalgae was done with controlled temperature, air flux of 4.5 l min⁻¹, salinity of 33‰ and an irradiance of 110±3 μmol m⁻² s⁻¹. Daily samples from the cultures were taken to estimate cellular density, proximate composition and chlorophyll a content during 7 days. Mean cellular density from samples with f/2 medium and with agricultural fertilizer were similar (no significance at P≤0.05), and mean growth rates of 0.62 and 0.61 doubling per day, respectively. Maximum similar values of protein content of 7.3 and 7.6 pg per cell were estimated on the 5th day in f/2 and agricultural fertilizer medium, respectively. Carbohydrate and lipid content decreased during the first 5 days corresponding to the exponential growth in both experiments. Higher content of carbohydrate (no significance at P≤0.05) was found in both media during the first 2 days, after 4 days the carbohydrates reduced three times theirs concentrations. Generally lipid contents in the cultures with agricultural fertilizer were significantly higher (P≤0.05) than f/2 medium. The chlorophyll a content increased exponentially during the culture, and its concentration was similar in both experiments. In conclusion, the cellular density and the biochemical constituents were similar when using either media. This fertilizer can be used in the production of I. galbana (T-Iso) employed in aquaculture.  相似文献   

Evidence of hybridization between Yaqui catfish Ictalurus pricei (Rutter, 1896) and channel catfish Ictalurus punctatus (Rafinesque, 1818) in north-west México revealed by analysis of mitochondrial and nuclear genes     

Alexsandre Gutiérrez-Barragán  Francisco Javier García-De León  Alejandro Varela-Romero  Carlos Alonso Ballesteros-Córdova  José Manuel Grijalva-Chon  Enrique De la Re-Vega 《水产资源保护:海洋与淡水生态系统》2021,31(11):3334-3341

1. The Yaqui catfish, Ictalurus pricei, is the only native ictalurid species described from north-west México and south-west USA. It is an endangered species owing to the decline and loss of most of its historical populations, mainly because of competition and hybridization with the non-native channel catfish, Ictalurus punctatus. The Arroyo Cajón Bonito is one of the few remnant populations of Yaqui catfish in the Yaqui River basin, and it is threatened by the presence of channel catfish that escaped from private culture facilities.
2. Phylogenetic analysis of two mitochondrial and two nuclear genes was used to detect evidence of hybridization with channel catfish in a collection of 20 catfish from Arroyo Cajón Bonito. Fourteen putatively pure Yaqui catfishes, five hybrids and one channel catfish were detected.
3. This study further highlights hybridization between channel and Yaqui catfish as the main threat to the remaining Yaqui catfish populations. We recommend urgent evaluation of the remnant populations of native catfish elsewhere and their current conservation status.

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Native trees and shrubs for the productive rehabilitation of tropical cattle ranching lands     

Enrique MurgueitioZoraida Calle  Fernando UribeAlicia Calle  Baldomero Solorio 《Forest Ecology and Management》2011,261(10):1654-1663

Extensive cattle production currently occupies more than 27% of the rural landscapes in Latin America, and continues to expand. This activity, deeply rooted in the culture and rural economy of the region, requires an urgent transformation if it is to become both more efficient and environmentally friendly. Silvopastoral systems that incorporate native trees and shrubs are instrumental for the productive rehabilitation of cattle production and for biodiversity conservation in agricultural landscapes. We discuss research progress and adoption of intensive silvopastoral systems in Colombia and Mexico. Intensive silvopastoral systems (ISS) are a sustainable form of agroforestry for livestock production that combines fodder shrubs planted at high densities (more than 10,000 plants ha⁻¹), trees and palms, and improved pastures. High stocking and the natural production of milk and meat in these systems are achieved through rotational grazing with electric fencing and a permanent supply of water for the cattle. While milk and meat production and cattle reproduction are enhanced, production costs decline as external inputs are replaced by natural processes related to fertility and biological control. We also discuss the importance of the ISS with native trees for climate change adaptation and mitigation, the barriers for their adoption, and how these have been successfully addressed using payment for environmental services, special credits and technical assistance. Finally, we highlight the need for enhancing landscape connectivity by integrating SPS to conservation corridors with native species to promote biodiversity conservation and other environmental services demanded by society.  相似文献   

CsSCL1 is differentially regulated upon maturation in chestnut microshoots and is specifically expressed in rooting-competent cells     

Vielba JM  Díaz-Sala C  Ferro E  Rico S  Lamprecht M  Abarca D  Ballester A  Sánchez C 《Tree physiology》2011,31(10):1152-1160

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Effect of diluting Marek's disease vaccines on the outcomes of Marek's disease virus infection when challenged with highly virulent Marek's disease viruses     

Gimeno IM  Cortes AL  Montiel ER  Lemiere S  Pandiri AK 《Avian diseases》2011,55(2):263-272

Dilution of Marek's disease (MD) vaccines is a common practice in the field to reduce the cost associated with vaccination. In this study we have evaluated the effect of diluting MD vaccines on the protection against MD, vaccine and challenge MD virus (MDV) kinetics, and body weight when challenged with strains Md5 (very virulent MDV) and 648A (very virulent plus MDV) by contact at day of age. The following four vaccination protocols were evaluated in meat-type chickens: turkey herpesvirus (HVT) at manufacturer-recommended full dose; HVT diluted 1:10; HVT + SB-1 at the manufacturer-recommended full dose; and HVT + SB-1 diluted 1:10 for HVT and 1:5 for SB-1. Vaccine was administered at hatch subcutaneously. One-day-old chickens were placed in floor pens and housed together with ten 15-day-old chickens that had been previously inoculated with 500 PFU of either Md5 or 648A MDV strains. Chickens were individually identified with wing bands, and for each chicken samples of feather pulp and blood were collected at 1, 3, and 8 wk posthatch. Body weights were recorded at 8 wk for every chicken. Viral DNA load of wild-type MDV, SB-1, and HVT were evaluated by real time-PCR. Our results showed that dilution of MD vaccines can lead to reduced MD protection, reduced relative body weights, reduced vaccine DNA during the first 3 wk, and increased MDV DNA load. The detrimental effect of vaccine dilution was more evident in females than in males and was more evident when the challenge virus was 648A. However, lower relative body weights and higher MDV DNA load could be detected in chickens challenged with strain Md5, even in the absence of obvious differences in protection.  相似文献   

Effect of toasting intensity at cooperage on phenolic compounds in acacia (Robinia pseudoacacia) heartwood     

Sanz M  Fernández de Simón B  Esteruelas E  Muñoz ÁM  Cadahía E  Hernández T  Estrella I  Pinto E 《Journal of agricultural and food chemistry》2011,59(7):3135-3145

The phenolic composition of heartwood from Robinia pseudoacacia, commonly known as false acacia, before and after toasting in cooperage was studied by HPLC-DAD and HPLC-DAD/ESI-MS/MS. A total of 41 flavonoid and nonflavonoid compounds were identified, some tentatively, and quantified. Seasoned acacia wood showed high concentrations of flavonoid and low levels of nonflavonoid compounds, the main compounds being the dihydroflavonols dihydrorobinetin, fustin, tetrahydroxy, and trihydroxymethoxy dihydroflavonol, the flavonol robinetin, the flavanones robtin and butin, and a leucorobinetinidin, none of which are found in oak wood. The low molecular weight (LMW) phenolic compounds present also differed from those found in oak, since compounds with a β-resorcylic structure, gallic related compounds, protocatechuic aldehyde, and some hydroxycinnamic compounds are included, but only a little gallic and ellagic acid. Toasting changed the chromatographic profiles of extracts spectacularly. Thus, the toasted acacia wood contributed flavonoids and condensed tannins (prorobinetin type) in inverse proportion to toasting intensity, while LMW phenolic compounds were directly proportional to toasting intensity, except for gallic and ellagic acid and related compounds. Even though toasting reduced differences between oak and acacia, particular characteristics of this wood must be taken into account when considering its use in cooperage: the presence of flavonoids and compounds with β-resorcylic structure and the absence of hydrolyzable tannins.  相似文献