内蒙古大兴安岭森林分类区划存在的问题及建议

森林分类区划是为了解决天然林的修养生息和恢复发展而提出的,但禁伐区、限伐区、商品林经营区划分在实施过程中存在一些问题。文章主要针对其存在的问题,提出一些可行性的建议和对策。     

Biofloc management with different flow rates for solids removal in the <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis> BFT culture system

Different water flows for solids removal in the Litopenaeus vannamei BFT system were evaluated. One control (no solids removal) and two treatments using different water flows, high (3945 L h^?1—HF) and low (1750 L h^?1—LF), were used with no water replenishment after each process, and the total dry weight of the solids was measured. L. vannamei (0.18 ± 0.06 g; 350 individuals m^?2) were stocked in 35-m^?3 tanks. For 17 weeks, the physical and chemical parameters were maintained within the recommended. To keep the total suspended solids concentrations at approximately 500–600 mg L^?1, clarifying was performed. The average water volume flowed by clarifiers was significantly different (p < 0.05) between HF (205 ± 34 m³) and LF (114 ± 24 m³). There was a significant decrease (p < 0.05) in the final tank volume in HF (28.09 ± 0.92 m³) and LF (28.62 ± 1.38 m³) due to the clarifying. Before clarifying (initial sample) and at the end of experiment (final sample) were not significantly different (p > 0.05) for crude protein, moisture or ash. The crude lipid of the LF in the final period was significantly lower (p < 0.05) compared to others in both periods. The survival, productivity and food conversion ratio were significantly better (p < 0.05) in the HF and LF treatments compared to those of the control. The best shrimp performance was obtained with solids removal. The lower flow in the clarifier facilitated particle settling, allowing adjustment of the flow.     

浅谈对森林认证的认识

文章通过对森林认证的特点、体系、机构、过程等方面的论述,阐述了森林认证对全球森林可持续经营的影响。     

Prevalence and characterisation of wounds in sheep attributed to attacks by kea (Nestor notabilis) on high country farms in New Zealand

ABSTRACT

Aims: To characterise and classify wounds in sheep suspected to have been caused by attacks by kea (Nestor notabilis) (kea strike), and to report the prevalence of these wounds on five high country farms in the South Island of New Zealand.

Methods: Data were collected from farms between 28 August 2012 and 20 September 2013. Sheep were examined opportunistically immediately after shearing for signs of wounds caused by kea. The age and sex of sheep were also recorded. Wounds were measured and characterised as recent, healing, or healed, and the estimated true prevalence was calculated for each farm.

Results: Injuries consistent with kea strike wounds were identified in 70/13,978 (0.5%) sheep examined. The estimated true prevalence varied between farms, from 0 (95% CI?=?0–0.16) to 1.25 (95% CI?=?0.97–1.61)%. Of the 76 wounds identified, 61 (80%) were located in the lumbar region, and 74 (97%) consisted of full-thickness ulceration of the skin, one showed evidence of injury to muscle and one to bone. The median length of the 63 wounds measured was 6 (min 1, max?23.5) cm, and 10/63 (13%) were categorised as recently healed, 47/63 (62%) as healing, and 17/63 (22%) as recent wounds.

Conclusions: The results of this study show that kea strike on sheep was occurring at a low prevalence on the high country farms surveyed. The wounds identified were survivable, but the welfare impact of kea strike on sheep should be considered in balance with the conservation status of kea. There was clear variation in the prevalence of wounds attributed to kea strike between the farms but we were not able to identify the risk factors contributing to these differences. Future studies of kea strike should examine variables such as altitude, local kea density and distribution, and differences in kea strike management and husbandry practices, and should include high country farms without a history of kea strike.     

Fusariosis in rubber tree: pathogenic,morphological, and molecular characterization of the causal agent

Fusariosis, one of the phytosanitary problems found in rubber producing areas in the northwest of the state of São Paulo, is a disease that affects the bark of the adult plants, affecting the exploitation of latex. The typical symptoms appear as cracks in the bark that expand from the rootstock towards the tapping panel, causing a drying of the latex flux in the injured region, impeding latex tapping. Due to the recent incidence of this disease in rubber plantations, the goal of this study was to characterize the Fusarium associated with symptomatic rubber tissue in three different locations in the state of São Paulo. In order to identify Fusarium species, pathogenicity, morphological, cultural and molecular studies were carried out. A total of 51 isolates were obtained and separated into three groups based on macroconidium morphology, presence or absence of sporodochia, types of chlamydospores, formation of phialides and conidiogenesis of microconidia and mesoconidia, mycelial growth rate and coloring of the colonies. These groups were corroborated using DNA sequence information for five different genetic loci, and were subsequently recognized as Fusarium oxysporum, F. incarnatum and F. decemcellulare. Our results further showed that all 51 of the Fusarium isolates recovered were pathogenic to rubber tree seedlings of RRIM 600 standard clone. This study also reports for the presence of F. oxysporum and F. incarnatum in rubber plantations in the state of São Paulo and in Brazil.

     

Diversity of Mycosphaerella spp. and Teratosphaeria spp. in Eucalyptus globulus plantations in Brazil

Among the most important diseases affecting Eucalyptus is Mycosphaerella Leaf Disease (MLD) caused by Mycosphaerella spp. and Teratosphaeria spp. MLD has led to significant losses in eucalypt plantations in the South and Southeast Region of Brazil, as well as in several countries such as Portugal, Spain, South Africa and Australia. Symptoms of MLD include localized necrotic spots, early defoliation in juvenile plants, stem cankers, early death of branches, and in some cases, atrophy and death. In the present study, single spore isolations from leaves of E. globulus from five locations in Brazil allowed the differentiation of species of Mycosphaerella and Teratosphaeria based on ascospore germination and growth in culture. These isolates were also subjected to sequence analysis of the ribosomal RNA internal transcribed spacer regions, which allowed their identification to species level. The results of this study showed that six species of Mycosphaerella and four species of Teratosphaeria were associated with leaves showing symptoms of MLD in E. globulus plantations in various locations of Brazil.     

Standard area diagram set to assess rust severity on eucalyptus leaves

This study aimed to develop and validate a standard area diagram set (SADs) to help assess rust severity caused by Austropuccinia psidii on eucalyptus leaves. The SADs has eight colour images of leaves with severity values ranging from 0.97% to 37.3%. The SADs were validated by 16 raters, who assessed the same set of 50 images twice: the first without the SADs and the second using it as an aid. Accuracy and precision of the estimates were determined based on Lin's concordance correlation coefficient, and the inter‐rater reliability was measured using the coefficient of determination (R²) and intraclass correlation. The estimates of severity of eucalyptus rust were more accurate, precise and reliable using SADs. These results demonstrate the value of SADs for several activities, including epidemiological studies, treatments comparison, disease monitoring, decision‐making in eucalyptus rust management measures, and in breeding programs.     

Effects of soil flooding on leaf gas exchange and growth of two neotropical pioneer tree species

Schinus terebinthifolius Raddi (Anacardiaceae) and Rapanea ferruginea (Ruiz & Pavon) Mez (Myrsinaceae) are two neotropical pioneer trees with wide geographical distribution in South America, highly degree of adaptation to different soil conditions and intense regeneration in areas with anthropic activities. With the aim to recommend the use Schinus and Rapanea in gallery forest restoration programs, we conducted an experiment with the objective to analyze the capacity of these two pioneer trees to tolerate soil flooding, mainly by accessing the effects of flooding on leaf gas exchange, growth and dry matter partitioning. Seedling survival throughout the 56-day flooding period were 100 and 90% for Schinus and Rapanea, respectively. The mean values of stomatal conductance (g_s) and net photosynthesis (A) observed in the control seedlings were, respectively, 0.4 mol m^–2s^–1 and 14 mmolm^–2s^–1, for Schinus, and 0.5 mol m^–2s^–1 and 14 mmolm^–2s^–1, for Rapanea. On day 20 flooding reduced gs and A by 36 and 29% in Schinus, and 81 and 61% in Rapanea. At the end of the experiment, significant decreases were also observed for root and whole plant biomass, in both species. Based on the results, we concluded that seedlings of Schinus and Rapanea can survive and grow throughout a medium period of soil waterlogging, in spite of the alterations observed in their physiological behavior, such as the decreases in stomatal conductance and in whole plant biomass.