Litter Thickness Research Articles

Epidemiological assessment of the factors associated with antimicrobial use in French free-range broilers

BackgroundAlthough the poultry sector accounts for a major portion of global antimicrobial consumption, few studies have explored the factors which influence antimicrobial use (AMU) in poultry farms in Europe. We performed a matched case-control study in traditional free-range broiler farms in France during 2016 to evaluate the effect of technical factors and farmers’ perceptions of health problems on the probability of AMU. In total, 52 cases (defined as flocks treated with antimicrobials when chickens were between 1 and 42 days old), were included. Another 208 controls (untreated flocks the same ages as the case flocks), were randomly selected and paired with a matching case (same farmer organization and placement date). On-farm questionnaires were administered. Multivariable logistic regression modeling was conducted; seven variables were significant in the final model.ResultsTwo factors were associated with a lower probability of AMU: the use of chicken paper topped with starter feed (OR = 0.3; 95% CI = [0.1; 0.9]) and the use of herbal drugs as a prophylaxis (OR = 0.1; 95% CI = [0.01; 0.5]). A higher probability of AMU was associated with farmers perceiving the cumulative mortality of chicks between 1 and 10 days old as normal (OR = 10.1; 95% CI = [1.7; 59]) or high (OR = 58.7; 95% CI = [9.6; 372.3]). A higher probability of AMU also was associated with farmers detecting a health problem (OR = 12.5, 95% CI = [4.2; 36.9]) and phone calls between farmers and their technicians (OR = 5.9; 95% CI = [2.3; 14.8]) when chicks are between 11 to 42 days old. Two additional factors (litter thickness and cleaning/disinfecting) were significant and highlighted the importance of technical factors such as biosecurity.ConclusionsOur results suggest that to reduce AMU, technical training should be provided to farmers to improve how farms are monitored and to reinforce preventive health measures. Training also should address how farmers assess warning criteria like daily mortality rates, which when overestimated often lead to antimicrobial treatment.

Decomposition of tree litter: Interaction between inherent quality and environment

Abstract. Rachmawati S, Yulistyarini T, Hairiah K. 2019. Decomposition of tree litter: Interaction between inherent quality and environment. Biodiversitas 20: 1946-1952. Litter layers protect forest soils, but may not be appreciated in recreation sites such as the Purwodadi Botanical Gardens (PBG), East Java, Indonesia. We quantified litter decomposition rates in mature stands of three tree species: mahogany (Swietenia macrophylla), angsana/narra (Pterocarpus indicus), and bungur/crape myrtle (Lagerstroemia thorelii). To separate inherent litter quality and stand-level environmental factors (such as microclimate, soil), decomposition rates were quantified for each species across all three stands. A possible interaction on decomposition rates is known as ‘home-field advantage’ (HFA). Litter-weight loss from TSBF-standard litter bags was observed at 0, 1, 2, 4, 8 and 12 weeks after litter bags were installed to estimate the half-life time (t50). We also solicited visitor views on the presence of a thick litter layer on garden floor. Decomposition of angsana (t50=48 weeks) was 15% faster at its ‘own home’ than in ‘neighbors home’. No significant HFA effects were found in bungur/crape myrtle litter that decomposed slower in its home environment, while mahogany decomposition was independent of location. Generally, PBG visitors knew the benefits of litter and were not bothered by its presence; litter increased the attractiveness for visitors to enjoy their happy days under the shade of trees in a ‘tropical autumn’.

Assemblage and Diversity of Anurans in Two Forests of the Western Ghats

The Western Ghats of India being a hotspot of biodiversity, amphibian population deserves precise and systematic exploration. In the present study, we evaluated the pattern of occurrence of anurans (during monsoon, post-monsoon and summer) in two forest ecosystems (evergreen and semi-evergreen) of the Western Ghats of Karnataka. Abiotic factors (air/water/soil temperature, humidity, illumination, canopy cover and litter thickness) in the forests chosen were assessed. The frequency of occurrence, diversity, evenness and expected number of species of anurans were calculated by standard methods. A total of 22 and 15 species of anurans was recorded in the evergreen and semi-evergreen forests, respectively. Species richness and diversity were higher in the evergreen forest than semi-evergreen forest. The diversity of anurans was higher during wet seasons (monsoon and post-monsoon) than dry season (summer). The rarefaction indices also revealed higher expected number of species during monsoon and or post-monsoon seasons than summer season. The anuran population composed of widespread, endemic and endangered species. The most frequent species of anurans recorded in this study include Clinotarsus curtipes, Duttaphrynus melanostictus, Euphlyctis cyanophlyctis, Fejervarya sahyadris, Hoplobatrachus tigerinus and Sylvirana temporalis. Among the anuran assemblage, Fejervarya sahyadris, Pseudophilautus wynaadensis, Raorchestes charius and Rhacophorus lateralis have been considered as the endangered species. The present study constitutes a baseline data on the anurans of Western Ghats of Karnataka.

Arthropod community at different altitudes in Gunung Halimun-Salak National Park, Western Java, Indonesia

Abstract. Haneda NF, Hilwan I, Irfani E. 2019. Arthropod community at different altitudes in Gunung Halimun-Salak National Park, Western Java, Indonesia. Biodiversitas 20: 1735-1742. Gunung Halimun Salak National Park (GHSNP) stores high biodiversity both from its flora and fauna. Parts of the diversity that have not been widely explored are soil arthropods at different altitudes. The aim of this study was to analyze soil arthropod community and the correlation between the attributes of soil arthropods and the environmental factors. The soil arthropods were collected using pitfall traps, placed in several altitudes, i.e., 500 m, 700 m, 900 m, 1100 m, 1300 m, 1500 m, and 1700 m . The attributes of community and environmental parameters were analyzed using Pearson correlation and principal component analysis. The result showed that family Formicidae dominated the soil arthropod community. The diversity of arthropods increased with increasing altitudes. The habitat at the altitudes of 1500 m, 1300 m and 1100 m had a dense canopy, thick litter and high total N and organic C. There was positive correlation between the attributes of soil arthropod community and environment variables.

Spatial distribution analysis of Dicksonia sellowiana Hook. in Araucaria forest fragments with different sizes.

Dicksonia sellowiana Hook. (Dicksoniaceae) is target of extractive exploitation and is threatened with extinction. We analyzed the population structure, the spatial distribution pattern of D. sellowiana and its relationship with environmental parameters within three fragments of Araucaria Forest in Rio Grande do Sul, Brazil. The fragments are of different sizes, namely, large (H1LF) with 246 ha, medium (H2MF) with 57 ha and small (H3SF) with 5.2 ha. Within each site, 1 ha was delimited, divided into 100 subplots (100 m2), of which 20 were selected with a draw. In each subplot, counting of the individuals, the registration of the caudice height and the coverage of leaves (SC) (m2), measurements of photosynthetically active radiation (PAR), canopy opening degree (CO), soil moisture (SM) and litter thickness (LT). The temperature (T) was measured inside each site. A total of 792 plants were sampled, of which 551 were concentrated in H1LF, 108 in H2MF and 133 in H3SF. An average of 1320 ha-1 individuals were estimated. Of the total including the three fragments, 96.9% of the individuals are in the first class of height (up to 0.8 m), indicating a great potential of population development. The spatial distribution pattern (AI) was aggregated in the three populations and the plants presented a heterogeneous total coverage, between 4.73 m2 (H2MF) and 2,223.47 m2 (H1LF). The highest values ​​of SC and SM were more related to the distribution of individuals in H1LF whereas the opposite was recorded in H2MF. The highest values ​​of PAR, LT and CO correlated with the distribution of D. sellowiana in H3SF. In addition to revealing that the H1LF population is among the most dense in southern Brazil, the results demonstrated a significant structural distinction between the interior populations of the fragments, in spite of them being located near to one another and being part of the same natural field matrix.

Soil macrofauna diversity and structure under different management of pine-coffee agroforestry system

The role of tropical forests for maintaining environmental functions is decreasing due to the rapid changes to agricultural purposes. Agroforestry system is assumed to be an alternative system which reduces the negative impact of the conversion in term of maintaining the level of soil macrofauna diversity. This study was conducted at UB Forest within the period November 2017 to February 2018 by collecting soil macrofauna from 9 different land use types using hand sorting along with pitfall sampling for comparison. ANOVA and various diversity indexes were used (Shannon index, Pielu index, etc) to determine macrofauna structure and communities. Total soil C was examined using Walkley and Black method along with Particulate Organic Matter (POM) C fractionation approaches. Litter inputs were collected using a litter trap method, whilst in-situ litter were determined using destructive methods. Biplot and CVA multivariate analyses were adopted to determine the impact of different management on soil macrofauna diversity and structure. The result showed that conversion to agriculture practices reduced the structure, population and abundance of soil macrofauna as litter production, organic matter and soil C content decreased. The lowest abundance of individual soil macrofauna at monoculture system (PM) was reduced to 45 morphospecies compared to pine coffee agroforestry at the age of 4 (PK4:20 years after planting) system as much as 104 morphospecies. There was a strong relationship between litter thickness and the abundance of soil macrofauna. Both methods (Hand sorting vs Pitfalls traps), had a different ability for collecting soil macrofauna communities. Species occurs at rich or low organic matter input can be adopted as soil macrofauna bioindicator of changes on an ecosystem. Biplot and CVA methods can be used to distinguish and to cluster the impact of different management at various agroforestry systems.

Patterns of Leaf Litter Decomposition as Related to Litter Traits in the Sudano-Guinea Savannahs of Ngaoundere, Cameroon

Litter decomposition processes are poorly studied in the savannahs. Leaf litter decomposition of the twenty-four contrasting plant species including trees, shrubs and grass species, was studied in the sudano-guinea savannahs of Ngaoundere, Cameroon. The litterbag technique was used to assess litter mass loss and single exponential model was adopted to estimate decay rate constants. Initial litter thickness varied from 0.02 to 1.11 mm, area from 4.27 to 245.89 mm2, sclerophyllous index from 0.01 to 1.75 mg.mm-2, density from 0.21 to 87.50 mg.mm-3, and specific mass area from 0.57 to 185.46 mm2.mg-1. Litter cellulose content varied from 3.79 to 11.84%; lignin from 2.84 to 8.12%, NDF from 21.35 to 80.41%, and total phenolic compounds from 0.47 to 17.76%. During the 52 weeks of the field experiment, mean dry mass remaining of litter samples was significantly between 8.05 and 75.22% of initial litter dry mass for C. papaya and C. regidus respectively. Litter decomposition rate constant (k) significantly ranged from 0.003 (C. regidus) to 0.121 %.week-1 (C. papaya). Litter mass remaining (LMR) was positively related to thickness (R2 = 0.605, P<0.01), Sclerophyllous index (R2 = 0.446, P<0.05), Specific mass area (R2 = 0.569, P<0.001), lignin (R2 = 0.631, P<0.01) and phenolic compounds (R2 = 0.618, P<0.001). The litter decomposition rate constant (k) was negatively related to thickness (R2 = 0.602, P<0.01, n=12), Sclerophyllous index (0.542; P<0.05), Specific mass area (0.419; P<0.05) and phenolic compounds (0.530; P<0.01). It can be concluded that litter decomposition is affected by plant species diversity, plant groups and physico-chemical traits of litters in the sudano-guinea savannahs of Ngaoundere, Cameroun. These preliminary results would contribute to understanding the mechanism of litter decomposition in general and in these savannahs in particular.

Developing a two-step algorithm to estimate the leaf area index of forests with complex structures based on CHRIS/PROBA data

Vegetation is a key factor affecting soil erosion, which depends not only on the horizontal structure of vegetation, but also on its vertical structure. The leaf area index (LAI) of plants, as an important structural parameter of the terrestrial ecosystem, can reflect horizontal vegetation coverage, vertical structure of vegetation, litter thickness and underground biomass. All these are the principal aspects of vegetation affecting soil erosion. The multi-angle remote sensing data can provide the stereoscopic and directional information of the surface target, which is helpful to extract the vertical structure parameters of vegetation effectively. Therefore, in order to improve the estimation accuracy of soil erosion, a two-step method was developed in this study to estimate the forest LAI under different vertical structures using the PROSAIL model and multi-angle CHRIS/PROBA data based on the field data. A total of 70 quadrats (10 m × 10 m sized) were deployed in Mount Zijin with undisturbed natural vegetation, considering the vegetation types and accessibility in the middle of August 2017. The pixels were first classified into two categories depending on complexity of vertical structure; then, a specific algorithm was applied to the different classes. For Class 1, the single angle data of 55° had the highest accuracy, indicating that, for forests with a simple vertical structure, the single angle data was sufficient for LAI estimation. For Class 2, the multi-angle data combination of 0°, 55° and −55° had the highest accuracy, indicating that, for forests with complex vertical structure, the multi-angle data can improve the accuracy of LAI estimation. The mean absolute percentage error (MAPE) and the root mean square error (RMSE) were applied to evaluate the accuracy of the LAI estimation algorithm. The results indicated that the two-step method can significantly improve the LAI estimation accuracy of forests with complex vertical structure, with a decrease in MAPE and RMSE of 19.52% and 23.08%, respectively, compared to the traditional empirical algorithm. The developed LAI estimation algorithm can be widely applied to forests with different vertical structures. Lastly, the two-step method was applied to the CHRIS/PROBA image acquired on September 7th, 2015 for mapping the spatial distribution of forest LAI in the western part of Mount Zijin. The result showed that the northern part and the southern part had higher LAI than the middle part of Mount Zijin.

The effect of vegetation change in C and N contents in litter and soil organic fractions of a Northern Iran temperate forest

The properties of litter and soil, which are probably influenced by vegetation traits, have an effect on the fractions of C and N and ultimately global warming. In this study, litter and soil samples were collected from representative forestlands, including a mixed natural forest dominated by hornbeam‑ironwood and tree plantations of ash, maple, cypress and pine which are situated in a temperate area of Northern Iran. Main litter characteristics, soil aggregation and fractions of C and N were studied. Pine had the highest values of litter thickness (14.46 cm), C (60.31%) and C/N ratio (81.77 and 20.28 for litter and soil, respectively). However, litter N (2.20%), micro aggregates of total soil (39.75%), aggregate stability (73.86%) and macro aggregates of total soil (54.87%) were found significantly higher under the natural stands. Total C (2.58%), C in macro and micro aggregates (0.31 and 0.33 respectively), POM-C (4. 68 g/kg), DOC (125.54 mg/kg) and C sequestration (45.34 Mg/ha) were considerably higher under pine (for POM-C, pine ≈ cypress) and the greater values of total N (0.34%), N in macro and micro aggregates (0.10 and 0.08 respectively), POM-N (0.47 g/kg), DON (33.80 mg/kg) and N sequestration (6.86 Mg/ha) were observed under natural stands. Under our conditions, conversion of natural forest is due to reduction of soil N fractions and C increased under pine tree plantations.

Decomposition of an N-fixing invasive plant compared with a native species: Consequences for ecosystem

Invasion by the Australian Acacia longifolia has significantly altered the characteristics of both vegetation and soil of Portuguese coastal dunes, including the accumulation of a thick litter layer. Although many aspects of impacts by this species in invaded dunes are known, decomposition of the litter is not well studied, but this can be crucial to disentangle both impacts and recovery. In order to better understand the impacts at soil level and the recovery of the system after removal of the invader, decomposition of A. longifolia litter was studied and compared with decomposition of the native Cistus salviifolius, for >3 years. Litterbags were deployed in a coastal sand dune and samples retrieved after 2, 5, 11, 17, 24, 36 and 41 months. At the final sampling, ca. 41% and 48% of the initial litter mass of A. longifolia and C. salviifolius, respectively, remained, showing that in these dunes both species decompose slowly. During the first 17 months, A. longifolia decomposed faster than C. salviifolius, but thereafter the rate slowed down and C. salviifolius was decomposed at a faster rate. In general, throughout decomposition, N and lignin content, lignin/cellulose ratio, cellulase and chitinase activity, and the number of microfungi morphotypes were significantly higher in A. longifolia than in C. salviifolius litter. On the other hand, C/N ratio, cellulose content and the number of microfungal isolates were generally higher in C. salviifolius litter. Mostly for A. longifolia, lignin content and lignin/N ratio increased as the remaining litter mass decreased. Despite high N content and low lignin/N and C/N ratios, almost 43% of the A. longifolia litter is recalcitrant/very slowly decomposed, accumulating on soil surface for long periods. The slow decomposition rate of A. longifolia litter together with the production of much more litter than the native vegetation (ca. 3 times more than C. salviifolius) is reflected in the accumulation of a thick N-rich litter layer on soil surface of invaded areas. This promotes a continuous input of C and nutrients to the soil, and leaves a hidden legacy long after the removal of the invader that, amongst other impacts, prevents the regeneration of native species.

Population study and habitat preferences of Pinang Jawa (Pinanga javana) in Mt. Slamet, Central Java, Indonesia

Abstract. Zulkarnaen RN, Nisyawati, Witono JR. 2019. Population study and habitat preferences of Pinang Jawa (Pinanga javana) in Mt. Slamet, Central Java, Indonesia. Biodiversitas 20: 712-718. Conservation effort of Pinang Jawa is hampered due to lack of information on its ecology and population biology. The species is an endemic palm species to Java. The study aimed to assess the population study and habitat preference of Pinang Jawa in Mt. Slamet, Central Java. The research design used a purposive sampling method with a plot measuring 10x10 m. The observation plot was successfully made with a total of 183 plots. The result showed that the population was dominated by adult palm (mature) with the number of 1023 individuals on the southern slope of Mt. Slamet. Individuals growth dominated in hill slope. Population structure was dominated by individuals with stem heights of 6.1-8.1 m and stem diameters of 7-8.9 cm. The stem height and stem diameter class distribution showed that high mortality rate occurs in the seedlings stage class, although this stage should be high recruitment due to the seed production is perennial continuously. Predators were identified as the main threat for seedlings of Pinang Jawa. The result of statistical analysis clearly provides reveals that abiotic factors in which influencing the density of Pinang Jawa was slope, litter thickness, and crown cover.

Effects of Chinese fir litter cover on its seedling emergence and early growth

Litter accumulation can strongly affect seedling emergence and early growth through both physical and chemical mechanisms, and can further influence natural regeneration. Chinese fir (Cunninghamia lanceolata) is one of the most important afforestation tree species. Its natural regeneration is poor, possibly due to the thick leaf accumulation inhibiting seedling emergence and growth. We used natural and plastic litter to study the effects of Chinese fir litter on its own seedling emergence and early growth, as well as to assess whether the effect was physical or chemical. In this experiment, two litter types (natural and plastic litter) and four different litter amounts (control, 0 g·m-2; low, 200 g·m-2; medium, 400 g·m-2; high, 800 g·m-2) were used. The results showed that compared to the control (0 g·m-2), low litter amount (200 g·m-2) exerted a slight positive effect on seedling emergence, whereas high litter amount (800 g·m-2) significantly reduced the seedling emergence and survival rate in the case of both natural and plastic litter. With increasing litter amount, root length of seedlings decreased and stem length increased. The highest and lowest root mass, leaf mass, and total mass of seedlings were observed for the low and high litter amount, respectively, in the case of both natural and plastic litter. The root:shoot ratio of seedlings decreased with the increasing litter amount for both natural and plastic litter. The photosynthesis:non-photosynthesis biomass ratio of the seedlings was higher under all litter cover treatments, compared to that in the control. Because the effect of the same amounts of the natural and plastic litter on seedling emergence and early growth did not differ, the litter layer's short-term influence was primarily physical. As the litter cover increased, the initial slight positive effects on seedling emergence and early growth could shift to inhibitory effects. Moreover, to penetrate the thick litter layer, Chinese fir seedlings allocated more resources toward stems and aboveground growth. This study provided evidence for litter amount being a key ecological factor that affects the seedling development and subsequent natural regeneration of Chinese fir.

Long-Term Postfire Changes of Soil Characteristics in Dark Coniferous Forests of the European North

Changes in characteristics of the upper soil horizons in dark coniferous forests in the course of their postfire restoration were assessed. The studies were carried out in the northern taiga forests exposed to fire 8 to 400 years ago in the Kola Peninsula and in the middle taiga forests burned 70 and more than 500 years ago in the northern Cis-Ural region (Pechoro-Ilychskii State Biospheric Reserve). Samples from 23 soil pits on 20 test plots were analyzed. The actual acidity, loss on ignition, contents of exchangeable K, Ca, and Mg and mobile Mn, Fe, and Zn were determined. Two boundaries (~80 and 160–200 years after fire) and three main periods in the postfire dynamics of the upper soil horizons properties were established. The ash and Fe content in the litter was found to decreases about 80 years after the fire. In 160–200 years after fire, the thickness of the forest litter is restored and stabilized at the level of about 9.7 (8.3–10.4) cm; the pH value and the Ca, K, and Mn concentrations in the litter become lower. Thus, it can be concluded that the properties of soils under dark coniferous forests of the European North considerably change in the course of postfire successions.

Soil physio-chemical and biological indicators to evaluate the restoration of compacted soil following reforestation

Reforestation of degraded forests with small to medium-scale monoculture plantation following mechanized ground-based harvesting has been widely applied in the past decades in Hyrcanian forests, but no studies have clearly characterized the restoration of soil properties following tree plantation in the temperate forests. We aimed to assess the efficacy of different plantation types (treatments) including Caucasian alder (Alnus subcordata; AS), Velvet maple (Acer velutinum; AV), and Italian cypress (Cupressus sempervirens var. horizontalis; CS) on the recovery of litter and soil properties over a 25-year period in the Tangar district in the Tyrumrud region of the Hyrcanian forests (Iran), compared to levels at the natural hornbeam-oak stand as a control. In each treatment (plantations with average length of 250 m and width of 200 m), three sample plots were measured and provided 81 soil samples. Tree species had significant differences on litter thickness and quality with the lowest litter thickness (4.2 cm), carbon (C) content (32.75%), and C/N ratio (15.56) and highest nitrogen (N) content (2.11%) in the Alnus subcordata (AS) plantation. Significantly higher recovery values of soil physical properties including soil bulk density, total porosity, macroporosity, penetration resistance, and aggregate stability were found in the AS plantation. However, soil physical properties did not fully recover in AS, Acer velutinum (AV), and Cupressus sempervirens (CS) plantation even after a 25-year period, compared to the control area. The significantly higher recovery of pH, EC, N, N storage, available nutrient, earthworm density, biomass, soil microbial respiration, and the lowest C, C/N ratio, C storage were observed in the AS plantation. The fine root biomass among the three plantation types did not fully recover compared to natural stands. Our study revealed that the roots of the planted trees initiated soil structure recovery, whereas the N-fixing tree species such AS significantly ameliorated the tested soil properties over a 25-year period following compaction.

Response mechanisms of leaf nutrients of endangered plant (Acer catalpifolium) to environmental factors varied at different growth stages

The response patterns of N and P in plant leaves are one of the tools for investigating the ability of plants to cope with current environmental conditions and predicting their future viability. Endangered species are more sensitive to environmental changes, lack of nutrients such as NP will adversely affect the survival of species. 119 Acer catalpifolium are the only ones left in the world were studied and were divided into different growth stages (small, adult and old trees) to study the environmental response of leaves to NP. Results showed that: the NP stoichiometric characteristics of Acer catalpifolium leaves were lower in small stage, with the growth of plants, the NP content increased. There was a significant correlation between the soil nutrient and leaf NP stoichiometry in all growth stages, and with the increase of soil N:P, the leaf N:P changed from N limitation to N and P limitation, showing a poor adaptability to soil environmental changes. Under the influence of environmental conditions, the adaptation strategy of leaf NP at different growth stages were different. With the return of nutrients, the leaf N:P at adult and old stages increased with litter thickness. Small and old stages showed poor adaptation with environmental changes. These results indicate that leaf NP differed significantly among different life stages and that these differences can accounted for part of the causes of endangerment of Acer catalpifolium.

湖南栎类天然次生林幼树更新特征及影响因子

PDF HTML阅读 XML下载 导出引用 引用提醒 湖南栎类天然次生林幼树更新特征及影响因子 DOI: 10.5846/stxb201806061269 作者: 作者单位: 中南林业科技大学,中南林业科技大学,贵州省植物园,中南林业科技大学,中南林业科技大学,中南林业科技大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31570631）；国家林业局项目（1692016-06） Regeneration characteristics and related factors affecting saplings in Quercus spp. natural secondary forests in Hunan Province, China Author: Affiliation: Forestry College, Central South University of Forest ＆ Technology, Changsha 410004, China,,Guizhou Botanical Garden,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以湖南典型栎类天然次生林为研究对象，基于51块样地的调查数据，采用k-means聚类分析划分林分类型，研究湖南不同栎类天然次生林幼树更新特征，分析了湖南不同栎类天然次生林幼树更新指标（幼树密度、幼树平均地径、平均高以及平均冠幅）与环境因子、林分因子的相关性，旨在阐明环境因子、林分因子对幼树更新的影响，以期为湖南不同栎类天然次生林的恢复与经营管理提供理论依据。结果表明：（1）利用聚类分析可将研究区内栎类天然次生林划分为5个类型，包括甜槠锥栗混交林（CC）、亮叶水青冈多脉青冈混交林（FC）、石栎樟树混交林（LC）、枹栎甜槠混交林（QC）、青冈栎混交林（CG）。（2）不同类型栎类天然次生林更新幼树优势种分化明显，物种丰富度差异显著（P < 0.05）。5种不同栎类次生林幼树密度均未超过500株/hm2，更新情况较差；幼树数量差异显著（P < 0.05），为亮叶水青冈多脉青冈混交林 > 石栎樟树混交林 > 青冈栎混交林 > 枹栎甜槠混交林 > 甜槠锥栗混交林；生长情况差异显著（P < 0.05），为青冈栎混交林 > 亮叶水青冈多脉青冈混交林 > 枹栎甜槠混交林 > 甜槠锥栗混交林 > 石栎樟树混交林。（3）相关分析结果显示，不同类型次生林幼树更新的主要影响因子存在差异。甜槠锥栗混交林中幼树密度与腐殖质厚度呈显著负相关（P < 0.05）；幼树平均高与灌木盖度呈显著正相关（P < 0.05）；幼树平均地径与草本盖度、灌木盖度呈显著正相关（P < 0.05）。亮叶水青冈多脉青冈混交林中幼树密度与海拔、腐殖质厚度、枯落物厚度呈显著正相关（P < 0.05），与草本盖度呈极显著正相关（P < 0.01）；幼树平均地径与郁闭度呈显著负相关（P < 0.05）；幼树平均高、幼树平均冠幅与坡位呈显著正相关（P < 0.05）。石栎樟树混交林中幼树密度与坡向、土壤厚度呈显著正相关（P < 0.05），其余因子对幼树生长无显著影响。枹栎甜槠混交林中幼树密度与郁闭度、乔木密度呈极显著正相关（P < 0.01），与坡位呈显著负相关（P < 0.05）；幼树平均冠幅与坡度呈显著负相关（P < 0.05）。青冈栎混交林中幼树平均地径与土壤厚度呈显著正相关（P < 0.05），与乔木密度呈极显著正相关（P < 0.01）；幼树平均冠幅与灌木盖度呈显著正相关（P < 0.05）。 Abstract:Quercus forest is a typical forest type in Hu'nan Province, which plays an important role in water and soil conservation, and maintaining ecological stability. However, most of the natural regeneration of Quercus forest in Hunan is poor, because of limited research on Quercus regeneration mechanisms, and ineffective management. Based on field investigation data, we analyzed typical Quercus natural secondary forests in Hunan, and used k-means cluster analysis to classify forest types. In this research, we studied sapling regeneration characteristics of different Quercus natural secondary forests in Hunan and examined the correlation of the sapling regeneration index (density, average ground diameter, average height, and average crown width of saplings) with environmental and stand factors in different Quercus natural secondary forests in Hunan. This study aimed to provide a theoretical basis for the restoration and management of natural secondary forests of different Quercus species in Hunan Province. The results showed that the natural secondary forest of Quercus could be divided into five types by cluster analysis, including Castanopsis eyrie-Castanea henryi mixed forest (CC), Fagus lucida-Cyclobalanopsis multinervis mixed forest (FC), Lithocarpus glaber-Cinnamomum bodinieri mixed forest (LC), Quercus serrata-Castanopsis eyrie mixed forest (QC), and Cyclobalanopsis glauca mixed forest (CG). The dominant species and species richness of the regeneration forests of different types of Quercus secondary forests were significantly different(P < 0.05). The sapling density in five different secondary forests of Quercus was < 500 trees/hm2, and sapling regeneration was poor. The number of saplings of different Quercus secondary forests was significantly different(P < 0.05), in the order of FC > LC > CG > QC > CC. The sapling growth status in different forests was significantly different(P < 0.05), and in the sequence of CG > FC > QC > CC > LC. The results of the correlation analysis showed that there were differences in the main factors affecting sapling regeneration in different types of secondary forests. In CC, there was a significant negative correlation between the sapling density and humus thickness(P < 0.05), a significant positive correlation between the average sapling height and shrub coverage(P < 0.05), and a significant positive correlation between the average sapling basal diameter and herbaceous and shrub coverage(P < 0.05). In FC, there was a significant positive correlation between sapling density and altitude, humus thickness, and litter thickness(P < 0.05), and a very significant positive correlation with herbaceous coverage(P < 0.01), a significant negative correlation between average ground diameter and canopy density(P < 0.05), and the average sapling height and crown width were significantly positively correlated with the slope position(P < 0.05). In LC, there was a significant positive correlation between sapling density and slope direction and soil thickness(P < 0.05), whereas the other factors had no significant effect on sapling growth. In QC, sapling density was extremely positively correlated with canopy and tree density(P < 0.01), and negatively correlated with slope position(P < 0.05), and the average sapling crown width was negatively correlated with slope(P < 0.05). In CG, the average sapling diameter was significantly positively correlated with soil thickness(P < 0.05), and had an extremely significant positive correlation with tree density(P < 0.01), and the average sapling crown width was positively correlated with shrub coverage(P < 0.05). 参考文献 相似文献 引证文献

Effect of wood shaving litter density on the growth, leg disorders and manurial value in broiler

&#x0D; The study was conducted with an aim to investigate the effect of litter density on growth, leg health and litter quality of broiler chickens from d1-42 days. Day-old male broiler chicks (n=400; Cobb 500) were distributed randomly into four litter densities [T1, T2, T3 and T4] treatments, each treatment had 5 replicates with 20 birds per replicate cage in a completely randomized design. Wood shaving was used as litter materials to a thickness of 5 cm, 8 cm, 11 cm and 14 cm on the floor of the pen. Birds were reared on the litter floor open-sided housing condition with ad libitum feed and water throughout the trail period. Data on feed intake (FI), body weight (BW), feed conversion ratio (FCR) and mortality were measured weekly. Litter sample was collected on day 42 to assess the nitrogen content (N2 %), dry matter (DM%) and moisture level (%). Footpad dermatitis (FPD) and hock burn (HB) incidences were measured on day 42 to assess the leg quality of birds. Results demonstrated that litter thickness had no significant (P&gt;0.05) effect on FI, BW, FCR and mortality of broilers from d1-42 days. The N2, DM or moisture levels (%) of litter were also unaffected (P&gt;0.05) between treatment. Leg disorders such as HB and FPD were influenced (P&lt;0.01) by treatment. The incidences of HB and FPD were higher (P&lt;0.01) in T1 and T2 than other treatments. It can be inferred from our current study that, leg health may be deteriorated by using low density wood shaving without affecting growth and litter quality of broiler chickens.&#x0D; Bang. J. Anim. Sci. 2018. 47 (1): 21-27&#x0D; &#x0D;

Influence of forest litter and rodents on the natural seed renewal process of forest biogeocoenoses of Dnepropetrovskaya oblast

As known, the natural seed renewal process flows under the influence of spontaneous climatic and biotic factors in forest biogeocoenoses. In this process in the conditions of steppe Ukraine the role of forest litter and the rodents’ activities is increasing especially.&#x0D; Investigations were carried out in natural and artificial forest biogeocoenoses of Prisamaria and Kirov forestry, as well as in reclaimed areas of the Western Donbass.&#x0D; Stocks of forest litter and the number of rodents (common vole, house mouse, field mouse etc.) have been studied according to conventional methods.&#x0D; It was found that in contrast to humid conditions in natural forests of steppe Ukraine the litter contributes to friendly seeds germination of main tree species ‒ English oak and Scotch pine. Thus the forest litter has a beneficial effect on such an important in the life of the forest process as the natural seed renewal. Only in rare cases when the litter thickness exceeds 4-5 cm (in the conditions of steppe such type of litter is very rare), there may be obstacles for seeds germination.&#x0D; The optimum number of rodents in natural systems without prejudice to homeostasis of biosystems can range between 50-80 individuals/ha. Significant increases in the number of rodents cause a decrease in natural regeneration. A trophic role of rodents should be considered as a positive factor in the young artificial forest reclaiming plantations.

Intraspecific variation in litter palatability to macroarthropods in response to grazing and soil fertility

Abstract Clarifying the functional consequences of intraspecific trait variability in response to interacting trophic levels would provide a significant improvement in our understanding of above‐ground–below‐ground linkages. In particular, the effects of grazing on plant traits may translate into altered litter quality, with potentially important consequences for litter‐feeding decomposers. Plant and litter variability in response to grazing is expected to depend on soil fertility levels, with tolerance and defensive strategies more commonly expressed on fertile and poorer soils, respectively. However, how grazing and fertility interactively alter litter quality and palatability to detritivores has not been explored yet. We conducted a cafeteria experiment with three common millipede (Diplopoda) species feeding on leaf litter from two plant species, the grass Bromopsis erecta and the forb Potentilla verna. Each millipede was offered a binary choice between litter types produced by the same plant species, but sampled in plots with distinct herbivory and fertilization status: litter originating from grazed areas or from 1‐year sheep exclosures, both in native areas and in adjacent paddocks that received chemical N and P fertilization, as well as litter from a 25‐year sheep exclosures in the native area. We found that fertilization and herbivore exclusion interactively affected Bromopsis litter quality and palatability, whereas Potentilla was much less affected. Bromopsis litter palatability was not affected by grazing when litter was collected in native plots, except for the long‐term exclosure which led to low palatability. In contrast, and in line with our expectations, herbivory was associated with much higher palatability in fertilized plots. The changes in palatability were associated with important alterations of litter quality. Overall, our study demonstrates that intraspecific variation in litter can have profound consequences for soil functioning. It emphasizes the role of grazing as a key, but plant species‐specific factor controlling litter intraspecific variability, and its complex interaction with soil fertility level. Moreover, our results advocate for a better understanding of the response of the different organisms involved in the decomposition process, in particular litter‐feeding macro‐detritivores. We encourage future studies aiming at disentangling the various and complex relationships between above‐ground processes such as herbivory and soil functioning.

MULTIVARIATE ANALYSIS OF THE ENDANGERED MEDICINAL SPECIES Cercidiphyllum Japonicum COMMUNITIES IN THE SHENNONGJIA RESERVE, CENTRAL CHINA

ABSTRACT Conservation for endangered medicinal plant species is important and urgent. Cercidiphyllum japonicum is an endangered and nationally protected medicinal plant species. We use multivariate methods to study ecological relations of C. japonicum communities in the Shennongjia Nature Reserve, Central China. Fifty-eight 10 m x 20 m quadrats of C. japonicum communities were randomly set up along an altitudinal gradient. Data for species composition and environmental variables were measured and recorded for each quadrat. Two-way indicator species analysis (TWINSPAN) and canonical correspondence analysis (CCA) was used in analyses. Moreover, species diversity indices were used to analyze the relationships between species diversity and environmental variables. The results showed that there were eight types of C. japonicum communities. Each community had its own compositional, structural and environmental characteristics. Variation of C. japonicum communities was significantly correlated to elevation and slope. Community variations were also related to aspect and litter thickness. Elevation and slope were revealed as important factors that influence community distribution and diversity. Species diversity showed a quadratic and negative correlation with elevation. The importance values of C. japonicum also showed a quadratic and negative correlation with species diversity. For conservational purposes, species diversity should be maintained within a reasonable range.