The Impact of Hardwood Line-Planting on Tree and Amphibian Diversity in a Secondary Subtropical Wet Forest of Southeast Puerto Rico     

Mark Nelson  Sally Silverstone  Kelly C. Reiss  Patricia Burrowes  Rafael Joglar  Molly Robertson 《Journal of Sustainable Forestry》2013,32(5):503-516

The impact on tree and amphibian diversity of line-planting of tropical hardwoods—mahogany (Swietenia macrophylla × S. mahagoni) and mahoe (Hibiscus elatus)—was studied in a secondary subtropical wet forest of Puerto Rico. Common coqui (Eleutherodactylus coqui) and melodious coqui (E. wightmanae) are the most frequent frog species; forest coqui (E. portoricensis) is less abundant. Although relative abundance means were slightly greater in the undisturbed forest and during the wet season, differences were not statistically significant suggesting that line-planting did not significantly affect amphibian diversity. The line-planted areas had a slightly higher, but not statistically significant diversity, richness, and evenness of tree species than the unplanted forest. Multi-response permutation procedure (MRPP) showed statistically significant community composition differences between line-planting and control plot trees (T = ?5.89, A = .86; p < .001). But mean similarity among plots in both the line-planted and control plots was relatively low at less than 50% of shared species, indicating high diversity of vegetation in the overall forest area. Canopy cover by tree species greater than 3 cm in dbh was much higher in the undisturbed forest but this difference may be reduced as the young line-planted hardwoods mature. Forest enrichment through line-planting of valuable timber species in secondary subtropical wet forest does not significantly affect tree diversity.  相似文献   

Thinning increases cone production of stone pine (Pinus pinea L.) stands in the Northern Plateau (Spain)     

Daniel Moreno-Fernández  Isabel Cañellas  Rafael Calama  Javier Gordo  Mariola Sánchez-González 《Annals of Forest Science》2013,70(8):761-768

Context

Edible stone pine (Pinus pinea L.) nut is a forest product which provides the highest incomes to the owners of stone pine forests.

Aim

The objective of this work is to evaluate the effect of first thinning on growth and cone production in an artificially regenerated stand in order to determine optimum intensity.

Methods

A thinning trial was installed in 2004 to compare two thinning regimes (heavy and moderate) and a control treatment. From 2004 to 2012, six inventories of forest attributes were carried out, and the cone crop was harvested annually. We evaluated the effect of thinnings on growth using repeated measures analysis of variance with a mixed model approach. With regards to cone production, we first estimated the probability of finding cones in a tree by applying a generalized mixed model and then estimated cone production by using a mixed model, including climatic variables.

Results

We found that thinning had a positive influence on tree diameter increment. Thinning increased the probability of finding cones and cone production. However, significant differences between heavy and moderate thinnings were not found.

Conclusion

We recommend early silvicultural treatments in stone pine stands to favor the development of trees and larger edible pine nut production.  相似文献   

Performance, growth, and maturity of Nellore bulls     

Luiz Fernando Costa e Silva  Sebastião de Campos Valadares Filho  Edenio Detmann  Polyana Pizzi Rotta  Diego Zanetti  Faider Alberto Castaño Villadiego  Samantha Gusmão Pellizzoni  Rafael Moura Guimarães Pereira 《Tropical animal health and production》2013,45(3):795-803

The objectives of this study were to evaluate the dry matter intake (DMI), digestibility, average daily gain (ADG), microbial efficiency, empty body weight (EBW) gain, and body composition of Nellore bulls. Additionally, Nellore bull maturity was estimated, and the prediction equation for DMI, suggested by the Brazilian nutrient requirements system (BR CORTE; Azevêdo et al. 2010), was evaluated. Thirty-three Nellore bulls, with a mean initial weight of 259?±?25 kg and age of 14?±?1 months, were used in this study. Five animals were slaughtered at the beginning of the experiment (control group), and the remaining 28 were divided into 4 groups, each slaughtered at 42-day intervals. Their diet was composed of corn silage and concentrate (55:45). The power model was used to estimate muscle tissue, bone tissue, crude protein (CP), mineral matter (MM), and water present in the empty body, while the exponential model was used to estimate adipose tissue and ether extract (EE) present in the empty body. When expressed in kilograms per day, differences were observed (P?<?0.05) only for the intake of EE and neutral detergent fiber as a function of feedlot time periods. Although there was a difference in relation to nutrient intake, it did not affect (P?>?0.05) digestibility, with the exception of EE digestibility. The equation suggested by BR CORTE correctly estimates the DMI of Nellore bulls. ADG was not affected (P?>?0.05) by time spent in the feedlot. No differences were observed (P?>?0.05) for microbial efficiency; a mean value of 142 g microbial crude protein/kg total digestible nutrients was achieved. The muscle and bone tissues, CP, MM, and water present in the empty body increased as the animal grew, although at a lower rate. The adipose tissue and EE present in the empty body increased their deposition rate when the animal reached its mature weight. Maturity is defined as when an animal reaches 22 % EE in the empty body, which corresponds to 456 kg of EBW in Nellore bulls. Therefore, this study can conclude that the feedlot time period does not affect DMI, nutrient intake, ADG, or microbial efficiency. The equation proposed by BR CORTE (Azevêdo et al. 2010) correctly estimates the DMI of Nellore bulls, which reach maturity when an EBW of 456 kg is attained.  相似文献   

Genotype by climate interaction in the genetic evaluation for growing traits of Braunvieh cattle in Mexico     

Luis A. Saavedra-Jiménez  Rodolfo Ramírez-Valverde  Rafael Núñez-Domínguez  José G. García-Muñiz  Nicolas Lopez-Villalobos  Agustín Ruíz-Flores 《Tropical animal health and production》2013,45(7):1489-1494

The objective of this study was to determine the magnitude of genotype by climate interaction (GCI) in the national genetic evaluation for weaning (WW) and yearling (YW) weights of Mexican Braunvieh cattle. The numbers of performance records and animals in the pedigree were 12,364 and 25,173 for WW, and 7,991 and 18,072 for YW, respectively. Performance records were clustered based on climatological variables into: dry tropic (DT), wet tropic (WT), and temperate (TE) climates. Animal models were used to estimate genetic parameters and predict breeding values in each of the climates. Bivariate analyses were carried out for pairwise combinations of climates on each trait, considering the same trait in different climates as a different trait. Criteria to evaluate GCI were genetic correlations (r _g), correlations between predicted breeding values (r _BV), and frequencies of coincidence (FC) in the ranking of the top 25 sires. Results of comparisons between pairs of climates were variable, depending on specific cases. For WW, the r _g, r _BV, and FC ranged from ?0.36 to 0.84, ?0.60 to 0.97, and 0.16 to 0.92, respectively; whereas for YW, they fluctuated between 0.23 and 0.99, 0.33 and 1.00, and 0.60 and 1.00, respectively. For both traits, the results suggest absence of GCI between DT and TE; however, GCI was detected in the other pairs of climates, where WT was involved. To maximize genetic progress, the joint genetic evaluation should be performed only for animals with performance data in DT and TE, whereas a separated evaluation is suggested for animals with performance records generated under WT conditions.  相似文献   

Linoleic acid increases adhesion,chemotaxis, granule release,intracellular calcium mobilisation,MAPK phosphorylation and gene expression in bovine neutrophils     

Jaqueline Mena  Carolina Manosalva  Ruben Ramirez  Lhia Chandia  Daniel Carroza  Anitsi Loaiza  Rafael A. Burgos  Maria A. Hidalgo 《Veterinary immunology and immunopathology》2013,151(3-4):275-284

Neutrophils are critical to the innate immune response; therefore, the proper function of neutrophils is critical to avoid the development of certain diseases. Linoleic acid, a polyunsaturated long-chain fatty acid, is one of the most abundant long-chain fatty acids found in the plasma of cows after giving birth. In this study, we evaluated the effects of linoleic acid treatment on bovine neutrophil adhesion, chemotaxis, metalloproteinase (MMP)-9 release, CD11b expression, intracellular calcium mobilisation, mitogen-activating protein kinase (MAPK) phosphorylation and COX-2 and IL-8 expression. Bovine neutrophils isolated from healthy heifers were incubated with different concentrations of linoleic acid, and then neutrophil responses were evaluated. Our results show that the treatment of neutrophils with 100 μM linoleic acid increased their adhesion to the bovine endothelial cell line CPA47. The results of a transwell migration assay revealed that linoleic acid could also promote the chemotaxis of bovine neutrophils. Furthermore, linoleic acid treatment increased MMP-9 activity and CD11b cell surface expression in neutrophils. Fifty and 100 μM linoleic acid also increased intracellular calcium mobilisation in neutrophils loaded with Fluo-4 AM dye. Linoleic acid also rapidly (2–5 min) stimulated the phosphorylation of ERK1/2 and p38 MAPK as evaluated by immunoblot. Finally, COX-2 and IL-8 mRNA expression increased after 2 h of linoleic acid treatment. In conclusion, linoleic acid stimulates adhesion, chemotaxis, granule release and intracellular responses in bovine neutrophils.  相似文献   

Gastrointestinal parasites in greater rheas (Rhea americana) and lesser rheas (Rhea pennata) from Argentina     

Rafael A. Martínez-Díaz  Mónica Beatriz Martella  Joaquín Luis Navarro  Francisco Ponce-Gordo 《Veterinary parasitology》2013

Few data exist on the parasites of ratites, especially from regions within their natural range. It is only recently that extensive studies on the parasites of ostriches (Struthio camelus) have been published, mainly from European countries where commercial farming has expanded. Two species of ratites are native in South America: the lesser rhea also known as Darwin's rhea (Rhea pennata) and the greater rhea (Rhea americana). Both species are considered near threatened by the IUCN and are included in the CITES’ Appendices I and II, respectively. Parasitological studies have conservation implications, as they allow us to assess the risk of transmission of pathogens from farmed ratites to wild populations. In this study 92 faecal samples from greater rheas and 55 faecal samples from lesser rheas from different localities in Argentine were analyzed to determine their gastrointestinal parasites. In greater rheas the protozoa (Balantidium coli-like and Entamoeba spp.) and helminths (Fasciola hepatica and Deletrocephalus spp.). The protozoa had not previously been cited as parasites of greater rheas in South America. Cysts and/or trophozoites of B. coli-like were found in 16.3% of the samples, while the prevalence of the remaining parasites was below 10%. Lesser rheas harbored the protozoa B. coli-like, Entamoeba spp. and Chilomastix spp. as well as F. hepatica and nematode eggs and larvae. B. coli-like cysts were found in 20.0% of the samples, while the prevalence of the other parasites remained below 5%. Some of them had not been cited as infecting lesser rheas yet.  相似文献   

Increased Inflammatory Mediators in Horses Naturally Infected with Trypanosoma vivax. A Preliminary Study     

Aleksandro S. Da Silva  Marta M.M.F. Duarte  Guilherme V. Bochi  Rafael N. Moresco  Lenita Moura Stefani  Silvia G. Monteiro 《Journal of Equine Veterinary Science》2013

The aim of this study was to measure the levels of inflammatory mediators in serum from horses naturally infected with Trypanosoma vivax. Banked serum samples collected during a previously reported T. vivax natural infection were used to analyze proinflammatory cytokines such as interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin 1 (IL-1), interleukin 6 (IL-6), and nitrite/nitrate (NO_x) levels. We evaluated 12 serum samples from horses from a farm in southern Brazil, four of which had parasitological and molecular diagnoses for T. vivax and presented with clinical signs of disease. Cytokines were assessed by quantitative sandwich enzyme-linked immunosorbent assay, and NO_x was measured using the modified Griess method. Levels of IFN-γ, TNF-α, IL-1, IL-6, and NO_x were increased in serum of infected animals compared to that in noninfected animals. Therefore, infection with T. vivax caused an increase in proinflammatory cytokines and nitric oxide content.  相似文献   

Assessment of hydraulic properties of technosols using Beerkan and multiple tension disc infiltration methods     

Deniz Yilmaz  Sofia Bouarafa  Pierre‐Emmanuel Peyneau  Rafael Angulo‐Jaramillo  Laurent Lassabatere 《European Journal of Soil Science》2019,70(5):1049-1062

  相似文献   

Impact of fertilization on cover crops and microbial community on a bauxite‐mined soil undergoing reclamation     

Rafael S. Teixeira  Ivan F. Souza  Rafael S. Santos  Lucas C. Gomes  Silvano R. Borges  Leonardus Vergütz  Ivo R. Silva 《植物养料与土壤学杂志》2019,182(4):515-523

The reclamation of bauxite‐mined areas can be favored by the application of organic and/or chemical fertilization to restore the vegetation. Otherwise, the impact of fertilizations on soil microbiota or plant–microbe interactions as land reclamation progresses is less understood. To address this issue, we evaluated the impact of organic and chemical fertilization on plants and soil microbial community within the first 36 months of land reclamation in a bauxite‐mined site. The experiment was set up according to a split‐plot design in which the main plots received fertilizations [non‐fertilized control (NF), chemical fertilization (CF; NPK and rock phosphate), organic fertilization (OF; poultry litter), and CF+OF combined], and the subplots received cover crops [no cover crops (NC), grass (B; Brachiaria), legume (S, Stylosanthes), and B+S combined]. Cover crops biomass yield was assessed annually with five field campaigns per year. We used phospholipid fatty acids (PLFAs) to infer the impacts of mining and restoration practices on actinobacteria, Gram‐negative and Gram‐positive bacteria, arbuscular mycorrhizal fungi, and fungi. Accordingly, PLFAs were determined before bauxite mining (pre‐mining), six months after topsoil reconfiguration (post‐mining), and after 14 and 36 months following the application of the fertilizations and cover crops. PLFAs results indicated that in post‐mining, the living microbiota was significantly lower than in pre‐mining. Cover crops biomass yield was highest for B and B+S fertilized with CF+OF at 14 and 36 months. Both parametric and non‐parametric statistics showed a temporal variation in the response of living microbes to the treatments applied. After 14 months, living microbes showed greatest response to OF, while at 36 months their response was strongest in the treatments with highest plant biomass production (B and B+S). These results suggest that in the early stages of land reclamation, living microbial biomass benefit the most from organic fertilizers. As this initial boost decline, living microbes are more likely to thrive in areas undergoing reclamation where they can develop synergistic interactions with plants.  相似文献   

Relative effects of fragment size and connectivity on bird community in the Atlantic Rain Forest: Implications for conservation   总被引：1，自引：0，他引：1  

Alexandre C. Martensen  Rafael G. Pimentel  Jean Paul Metzger 《Biological conservation》2008,141(9):2184-2192

It is known that large fragment sizes and high connectivity levels are key components for maintaining species in fragments; however, their relative effects are poorly understood, especially in tropical areas. In order to test these effects, we built models for explaining understory birds occurrence in a fragmented Atlantic Rain Forest landscape with intermediate habitat cover (3%). Data from over 9000 mist-net hours from 17 fragments differing in size (2-175 ha) and connectivity (considering corridor linkages and distance to nearby fragments) were ranked under a model selection approach. A total 1293 individuals of 62 species were recorded. Species richness, abundance and compositional variation were mainly affected by connectivity indices that consider the capacity of species to use corridors and/or to cross short distances up to 30 m through the matrix. Bird functional groups were differently affected by area and connectivity: while terrestrial insectivores, omnivores and frugivores were affected by both area and connectivity, the other groups (understory insectivores, nectarivores, and others) were affected only by connectivity. In the studied landscape, well connected fragments can sustain an elevated number of species and individuals. Connectivity gives the opportunity for individuals to use multiple fragments, reducing the influence of fragment size. While preserving large fragments is a conservation target worldwide and should continue to be, our results indicated that connectivity between fragments can enhance the area functionally connected and is beneficial to all functional groups and therefore should be a conservation priority.  相似文献