Propolis is a resinous substance collected by honeybees from various plant sources. On account of its chemical composition, propolis possesses several biological and pharmacological properties. In recent years, many papers have provided information concerning its composition. This review compiles data from most studies of propolis, focusing on the chemical composition of ethanol extracts of propolis (EEP), water extracts of propolis (WEP), and volatile oils from propolis (VOP). The characteristic compounds of EEP are polyphenols including flavonoids and related phenolic acids, and flavonoids are the most abundant and effective parts. They are considered to contribute more to the antibacterial, antiviral, and antioxidant effects than the other constituents. The main flavonoids in EEP are pinocembrin, galangin, chrysin, quercetin, kaempferol, and naringenin. The constituents reported to be in WEP include phenolic acids, caffeoylquinic acid, 3-mono-O-caffeoylquinic acid, caffeic acid, flavonoids, etc. The propolis volatile compounds are benzyl alcohol, benzyl acetate, cinnamic alcohol, vanillin, eudensmol, cyclohexyl benzoate, and benzyl benzoate, which are responsible for several biological properties. As a natural mixture, propolis is widely used in medicine and cosmetics, as well as being a constituent of health foods. Since propolis has been used extensively, information on its composition is not only of interest to the academic field, but also to propolis users.

48\a8\81\91\hcm0000099188.html

Pollution from concentrated animal feeding operations (CAFOs) are the most serious pollution source in China now, and swine wastewater contains high concentrations of nutrients such as chemical oxygen demand (COD), biochemical oxygen demand 5 (BOD₅), ammonium, and emergent contaminants related to public health. Biological processes are the most popular treatment methods for COD and ammonium removal. Considering the low operation cost, easy maintenance and high removal rate of contaminants in recent years, nitrogen removal via nitrite and real-time control processes using oxidation-reduction potential (ORP) and/or pH as parameters to control the aerobic and anaerobic cycles of a system has received much attention for animal wastewater treatment. During the biological treatment process, the emergent contaminants such as estrogen, antibiotics, and disinfection reagents have been the focus of research recently, and degradation bacteria and resistance bacteria have also been extracted from activated sludge. The microbial analysis technique is also advancement in the field of biodegradation bacteria and resistance bacteria. All of these advancements in research serve to improve wastewater treatment and decrease environmental hazards, especially for using manure as a fertilizer source for crop production.

With the popularization of microarray experiments in biomedical laboratories, how to make context-specific knowledge discovery from expression data becomes a hot topic. While the static “reference networks” for key model organisms are nearly at hand, the endeavors to recover context-specific network modules are still at the beginning. Currently, this is achieved through filtering existing edges of the ensemble reference network or constructing gene networks ab initio. In this paper, we briefly review recent progress in the field and point out some research directions awaiting improved work, including expression-data-guided revision of reference networks.

Changes in the sucrose metabolism of Curcuma longa L. plants were studied under treatment with different triazole compounds viz., triadimefon (TDM) and propiconazole (PCZ). Plants were treated with TDM at 15 mg/L and PCZ at 10 mg/L separately by soil drenching on 80, 110, and 140 days after planting (DAP). The plants were harvested randomly on 90, 120, and 150 DAP to determine the effect of both the triazoles on sucrose metabolizing enzymes and phenol content. The sucrose metabolism was studied by analyzing sucrose metabolizing enzymes like sucrose synthase and sucrose phosphate synthase. All the analyses were assayed in leaves and tubers of both control and treated plants. It was found that both of the triazole compounds had profound effects on these parameters.

Soil microhabitats and their heterogeneity are often considered to be among the most important factors affecting soil biotic communities. The microbial community has become one of the most important links in soil nutrient cycles and trophic components due to its role in biological processes, spatial and temporal dynamics, and physiological adaptation. Sandy-soil desert systems are characterized by fast water infiltration during the rainy season, high salinity, and low moisture availability in the upper soil layers. Plants have developed different ecophysiological adaptations in order to cope with this harsh environment. The Tamarix aphylla is known to be one of the most commonly adapted plants, exhibiting a mechanism for secretion of excess salts as aggregates through its leaves. These leaves aggregate beneath the plant, creating ’islands of salinity’. Soil biotic components are, therefore, exposed to extreme abiotic stress conditions in this niche. The goal of this study was to examine the effect of T. aphylla on the live/dead bacterial population ratio on a spatial and temporal scale. The results emphasize the effect of abiotic factors, which changed on temporal as well as spatial scales, and also on the size of the active soil bacterial community, which fluctuated between 1.44% and 25.4% in summer and winter, respectively. The results of this study elucidate the importance of moisture availability and the ’island-of-salinity’ effect on the active microbial community in a sandy desert system.

A study dealing with the marine fungi associated with decaying wood samples in the brackish water mangrove ecosystem and shoreline ecosystem was carried out in south India. A total of 19 marine fungi were isolated from the brackish water mangrove ecosystem. They included 13 Ascomycetes, one Basidiomycete and five Mitosporic fungi. In terms of percent frequency of occurrence, the most frequent species obtained from the brackishwater were the Lignincola longirostris (16.60%) and Savoryella lignicola (12.09%). Nine species were found frequently. Five species were occasionally encountered. Aigialus mangrovei, Aniptodera mangrovei and Halosarpheia marina were the rare species recorded. The average number of isolates per wood sample was 1.53. A total of 27 marine fungi including 15 ascomycetes, one basidiomycete and ten mitosporic fungi were recorded from the shoreline ecosystem. In terms of percent frequency of occurrence, the most frequent species obtained from Kanyakumari were the Arenariomyces trifurcates (13.66%), Corollospora maritima (12.44%), and Cirrenalia pygmea (10.98%). Seven species were found frequently. Fourteen species were occasionally encountered. Three species were found to be rare in occurrence. The average number of isolates per wood sample was 1.21.

We investigated the possible existence of superoxide dismutase (SOD; EC 1.15.1.1) isoenzymes in the pollen of Nicotiana tabacum (Petit Havana SR-1 cultivar). To detect SOD activity, crude extracts from tobacco pollen were subjected to native polyacrylamide gel electrophoresis followed by staining with nitroblue tetrazolium (NBT). The presence of six SOD isoenzymes was detected in tobacco pollen. Treatment with SOD inhibitors indicated the presence of one manganese SOD (Mn SOD), five copper-zinc SOD (Cu/Zn SOD) isoenzymes, and the absence of iron SOD (Fe SOD).

Using common beans differing greatly in the response to photoperiod and low-phosphorus (P) stress, we investigated their responses to acidity and aluminum (Al) toxicity and the relationship between Al tolerance and organic acid exudation under Al or low P stress. A genotype Ginshi was found to be sensitive to low pH treatment. When exposed to pH 4.5, serious curvature in the root tips of cv. Ginshi was observed; however, it was completely corrected by the application of 5 or 10 μmol/L AlCl₃; increasing calcium (Ca) could ameliorate Al toxicity, but it could not correct root curvature at pH 4.5. Common beans showed significant differences in both root growth and Al tolerance, and the varieties from the Andes were more tolerant to Al toxicity than those from the Mesoamerican origin. In the presence of 50 μmol/L AlCl₃, all the common bean genotypes exuded citrate, and a significant difference in the amounts of citrate was observed among genotypes. The genotypes originated in the Mesoamerica tended to release more citrate than other origins in the presence of Al. The P-inefficient genotype DOR364 exuded more citrate than the P-efficient genotype G19833 in the presence of 50 μmol/L AlCl₃, whereas no organic acids were detected in root exudates under low-P stress. A reduction of citrate exudation in the DOR364, but a slight increase of citrate exudation in the G19833, was observed under Al stress after they were exposed to 6-d P starvation. These results suggest that different low-P or Al tolerance in common beans might not be associated with organic acid exudation.

The growth of flue-cured tobacco is sensitive to changes in environmental conditions. Excellent tobacco leaf production is strictly restricted by regional cultivated lands. For the purpose of reasonable utilization and scientific management of Sanmenxia tobacco fields, it is meaningful to evaluate the soil fertility suitability of tobacco crops quantitatively and objectively. In this study, the global positioning system (GPS) technology was used to obtain sample point information automatically. Based on the analysis of fertility properties of soil samples collected from the Sanmenxia tobacco planting regions in Henan Province, we present the index system of soil fertility suitability for tobacco crops. The integrated evaluation of soil fertility suitability was studied with six indices, including organic matter, pH value, available nitrogen (N), available phosphorus (P), available potassium (K), and chlorine (Cl^−1) content of surface soil. The subjective grade value was calculated according to S-type and parabola-type functions of the effect of evaluation factors on tobacco crops. Further, the weight value of soil fertility suitability indices was calculated by the method of Hiberarchy analysis. The soil fertility suitability level was evaluated and classified. The suitability map of the Sanmenxia tobacco planting regions in Henan Province was then drawn with the geographic information system (GIS) software mapGIS. It was found that highly suitable fields were mainly distributed in the high mountains in the Southwestern part of the investigated regions where soil pH value and the contents of organic matter were medium, but the contents of available P and available K were higher, accounting for 79.36% of the whole area. Suitable fields were 17% of the whole area, mainly distributed in the middle part of the investigated regions where soil pH value was higher. Unsuitable fields existed in the northern-east and middle part of the Sanmenxia where the contents of soil Cl^− was very high, accounting for 3.51% of the whole regions.

Camellia ptilophylla Chang is a wild tea tree containing theobromine and is caffeine-free. Lots of researches have been conducted for its domestication since it was discovered to contain theobromine in its shoots. First, its pharmacological and physiological effects have been studied, demonstrating that it can be used as a new resource of tea as daily and healthy beverage. Cocoa tea differs from traditional tea in that it does not excite the nervous system. Second, various ways of propagation have been investigated, and sexless cutting has been the method adopted currently. Third, through selection and breeding, plantation of cocoa tea can be set up to cultivate new varieties, and cocoa tea of different flavors such as green cocoa tea, oolong cocoa tea, and black cocoa tea can be processed. Thus, cocoa tea will become a choice in the tea market.

Geostatistical methods were used in combination with geographical information system (GIS）technology to analyze the spatial distribution characteristics of available zinc, copper, and manganese in the Xiangcheng tobacco planting fields, Henan province, China. Analysis of the isotropic variogram indicated that the Zn semivariogram was well described with the Gaussian model, with the distance of spatial dependence being 900.7m; while the Mn semivariogram was well described with spherical models, with the distance of spatial dependence being 14 060m; and, the Cu semivariogram was well described with exponential models, with the distance of spatial dependence being 27 860.7m. Mn and Zn were strongly spatially dependent, with the C0/sill being 0.014 and 0.147 in this given region; while Cu was moderately spatially dependent, with the C0/sill being 0.3528. With the kriging analysis, the spatial distribution maps of contents of these three trace elements in the Xiangcheng tobacco planting regions was drawn with the Arcview software. It was found that the soils with higher content of Mn were mainly distributed in the high mountains of the southern part of the given regions, while the soils with higher content of Cu were mainly distributed in the south, decreasing from the south to the north. The soil with contents of Zn in the range of 0.76―1.33mg/kg existed in the high mountains of the west and middle parts of the investigated regions, accounting for 76.11% of the whole area.

The objective of this paper was to assess the congruency of leaf traits and soil characteristics and to analyze the survival strategies of different plant functional types in response to drought and nutrient-poor environments in the southeastern Ke’erqin Sandy Lands in China. Six leaf traits—leaf thickness (TH), density (DN), specific leaf area (SLA), leaf dry weight to fresh weight ratio(DW/FW), leaf N concentration (N_mass), and N resorption efficiency (NRE_mass)—of 42 plant species were investigated at four sites. The correlations between leaf traits and soil characteristics—organic C (OC), total N (TN), total P (TP), and soil moisture (SM)—were examined. We found that the six leaf traits across all the 42 species showed large variations and that DW/FW was negatively correlated with OC, TN, TP, and SM (P < 0.05), while other leaf traits showed no significant correlations with soil characteristics. To find the dissimilarity to accommodate environment, a hierarchical agglomerative clustering analysis was made of all the species. All the species clustered into three groups except the Scutellaria baicalensis. Species of group III might be most tolerant of an arid environment, and species of group II might avoid nutrient stress in the nutrient-poor environment, while group I was somewhat intermediate. Therefore, species from the different groups may be selected for use in vegetation restoration of different sites based on soil moisture and nutrient conditions.

Delay in seed release is found in the dune ecosystem. However, its functions have been rarely reported. We studied delayed seed release in the Agriophyllum squarrosum (Chenopodiaceae), an annual psammophyte, and the Artemisia wudanica (Asteraceae), a psammophilous subshrub in an active sand dune field in Inner Mongolia, China, to get insights into its functions in dealing with sand movement. We concluded that delay in seed release in the dune ecosystem are as follows: (1) postponing dispersal of a portion of seeds until the end of windy season and the start of growing season; (2) regulating the spatiotemporal pattern of seed bank; (3) helping psammophytes adapt to wind erosion on the active sand dune; and (4) helping psammophytes realize long-distance dispersal.

This paper introduces the two-dimensional (2D) wavelet analysis as a general interrogative technique for the detection of spatial structure in lattice data. The 2D wavelet analysis detects components of hierarchical structure and displays the locational information of the components. Patches and gaps of different spatial scales in graphical presentation of wavelet coefficients can be linked to the local ecological processes that determine patterns at stand or landscape scales. Derived from the 2D wavelet transform function, the calculation of wavelet variance can reduce the four-dimensional data of wavelet coefficients to a two-dimensional wavelet variance function and quantify the contribution of the given scale to the overall pattern. We illustrate the use of the 2D wavelet analysis by analyzing two simulated patterns and identifying the regeneration pattern of the Quercus liaotungensis in a warm temperate forest in north China. Our results indicate that the recruitment of Q. liaotungensis occurs in an overlapping area between the patch of adult and canopy gap at scales of 45 m × 45 m―70 m × 70 m and 20 m × 20 m―30 m × 30 m. The regeneration pattern of Q. liaotungensis can be mainly ascribed to a trade-off between two ecological processes: recruitment around parent trees and the physiological light requirements of seedlings and saplings. Our results provide a general portrayal of the regeneration pattern for the dispersal-limited and shade-intolerant Quercus species. We find that the two-dimensional wavelet analysis efficiently characterizes the scale-specific pattern of Q. liaotungensis at different life-history stages.

Shennongjia represents an area of considerable plant biodiversity, not only for China but for the whole world. The numerous species are distributed along an altitude gradient. The genus Fagus, commonly known as Beeches, constitutes one of the dominant woody species of the humid temperate forests in China. This paper deals with the community structure of a mixed, broadleaved deciduous-evergreen beech forest dominated by the Fagus engleriana and Cyclobalanopsis oxyodon, which occurs along an altitude gradient range in this area. The community consists of 46 woody species, belonging to 22 families and 27 genera. The tree layer can be divided into three sub-strata. The upper layer is composed of deciduous trees, 80.7% of which is F. engleriana. The second and third layers are dominated by the evergreen species, such as C. oxyodon and the Rhododendron hypoglaucum. These species increase from 55.9% in the second layer to 80.5% in the third, and regeneration at that rate allows us to assume that the stability of the community may be guaranteed. The micro-site heterogeneity plays an important role in maintaining species diversity in plant communities. In this research, a terrain surface of 0.96 hm² was simulated using the digital elevation model (DEM) in order to analyze the influence of the topography on plant community structures on a small scale. The slope relief aspect obtained with the DEM showed an accentuated heterogeneity. Semivariance analysis was used to measure the heterogeneity scale. The range and nugget variance of the semivariograms for slope were 285.8 and 280.5, respectively; for aspect, were 21.8 and 498, respectively. The elevated value of the nugget variance suggested that even on a small scale, the topographic variations influenced the species distribution. Twenty-four species were selected to estimate the correlation coefficient between the slope, aspect, and orientation. Then based on the correlation results using the Square Euclidean Distance cluster analysis, the 24 species were divided into four groups.

The Janzen-Connell (J-C) hypothesis provides a mechanism explaining the high species diversity in tropical rainforests. It postulates that predation could cause greater mortality on seeds and seedlings near their parental trees. In this study, we tested the hypothesis in a subtropical zone, a mixed evergreen-deciduous broadleaved forest dominated by the Fagus engleriana and Cyclobalanopsis oxyodon. The study area was in the Shennongjia region, a key area of biodiversity conservation in both China and the world. The recruitment probability index was used to detect the J-C effect on nine species of the community, which were more than 50 individuals. Six large adults of each species were selected, and the numbers of saplings and adults were counted at the distance intervals of 0―5, 5―10, 10―15, 15―20, and 20―25 m from each focal tree. Two species in saplings stage and six in adult stage supported the J-C hypothesis, but their χ² was not significant. Three species, the F. engleriana, Rhododendron hypoglaucum, and Toona sinensis, showed a strong Hubbell pattern in the adult stage. Because of these results, we reject the J-C hypothesis and conclude that species could recruit near the conspecific trees in subtropical forest. The reasons why the J-C hypothesis fails to explain the species diversity in this community are the shortage of seed-consuming agents of subtropical forest and the influence of microsite topographic variation.

In cold or alpine areas of northern China, birch forests and larch forests are the two primary forest types. These forests are also characteristic of a south branch of boreal forests in Asia. Some ecologists argue that larch forests can replace birch forests, but this still remains a question due to fragmentary or short observations. The ecotone between a larch forest patch and a birch forest patch is the arena in which the two species interplay and compete with each other, and studies of these areas are meaningful to understanding forest succession. In the alpine area of the Baihuashan Reserve, northern China, we sampled a larch-birch forest ecotone with eight plots in four transects and then analyzed population structures of larches and birches. The results show that the edges of the larch forest patch are composed of many larch saplings or young trees, but the edges of the birch forest patch are mainly composed of old birches. Across the ecotone, the larches, on average, are taller than the birches. These facts suggest that larch saplings can permeate into birch forest patches, probably by seed dispersal, germination, successful competition and growth, but birch saplings cannot permeate into larch forest patches. Therefore, on the ecotone, larch forest patches can steadily expand by unceasing permeation into birch forest patches, whereas birch forest patches progressively recede due to ultimate death of the old and poor recruitment of the young. Larch forest patches replace birch forest patches in a stepwise manner, causing succession from birch forests to larch forests. This study not only confirms that larch forests can naturally replace birch forests, but also introduces a simple and reliable method, employing spatial hints, to study forest succession. Additionally, the findings are of benefit to cultivation or development of larch forests in cold or alpine areas of the North Temperate Zone, which can be a huge carbon sink.

Ecological assembly rules in evergreen broadleaved forest are far from clear understanding. Spatial dispersion of individuals in a species is central in ecological theory. We analyzed the spatial patterns as well as associations between adult and juvenile of each tree species in a 5-ha subtropical evergreen broad-leaved forest plot in eastern China. Out of the 74 species occurring with more than 10 individuals, 88.4% of these species are aggregated. Most of them are aggregated from small to large scales. Spatial distributions of some species correspond with topography. Many bad dispersed species in the Baishanzu exhibit a highly aggregated distribution at small scales. These suggest that environmental heterogeneity and/or dispersal limitation may be the most important mechanisms that control the distribution patterns of these species. Our observations of the aggregations of abundant species basically support the hypothesis that dispersal limitation decreases as the number of reproductive limitation trees increases. The rest species are randomly distributed, with less than 10 individuals. For most common species, spatial aggregation is weaker in larger diameter classes, and the distance between adults is larger than that between juveniles and adults, suggesting that density-dependence works on loosing aggregation and excluding nonspecific juvenile to form adult trees. However, the density-dependent effect is not strong enough to eliminate all seedlings near adult trees and to result in a regular distribution of trees; thus the density dependence is usually masked by the refuge effect.

A survey was conducted with the aim to document the indigenous information of Charkotli Hills, Batkhela District, Malakand, Pakistan. The area has rich vegetation and a high potential for ethnobotanical utilization. Information was collected on various traditional uses of 100 plants distributed over 49 families, of which 43 families were of dicot, 2 of monocot, 2 of pteridophyta, and 1 of gymnosperms. Most plants have more than one local use. Sixty-six plants were found to be medicinal species, 21 fruit and edible seed species, 11 furniture species, 18 fodder or forage species, 12 vegetable species, 12 fuel species, 11 thatching and building species, 5 hedge or fencing species, 5 timber wood species, 5 poisonous plants, 3 species used in ketchup, 2 fixed oil yielding species, 2 miswak species, 2 species for making sticks for cattle and defense purposes, 2 species cultivated for ornamental purposes, 2 species used as mehindi by girls, 1 irritant species, 1 species for the making of Salai (a little stick for applying ‘surma’ to the eyes), 1 species for tanning, 1 species used as refresher in milk pots, 1 species giving gum used as chewing gum, and 1 species used as insect repellent. The area is under heavy pressure of deforestation and overgrazing, which have reduced the regeneration of woody plants. Proper ecological management is required to protect the wildlife and ethnobotanical resources for the coming generations.

This study was conducted in the Banni region of the Gujarat State, India, which is located in the western-most end of the country. The main objective was to investigate the local perceptions of grassland change, regeneration potentiality, socio-economic status and factors that cause degradation of the vegetation resources in Banni. Participatory Rural Appraisal (PRA) was employed to generate the socio-economic profile of interviewed villages or hamlets. Information on vegetation deterioration and changes in species composition significant for sustainable management of grassland was obtained through interviews with 51 elderly maldharies (pastoralists) and local inhabitants living in 31 villages in Banni. Local people had observed a change in the local surrounding habitats from grassland to woodland (dominated by Prosopis juliflora, locally called Gando Bavar) during their lifetime and considered it primarily a result of frequent intensive drought, constructed dams on flooding rivers in Banni, and declining rainfall. The socio-economic survey showed that the Banni communities are highly dependent on the natural grassland for various purposes. In particular, nine woody species were useful for construction of the traditional house called Bhunga, four for medicine and 22 for livestock fodder. Highly preferred and declining species were characteristically large wild thorny trees with edible fruits, viz.Acacia nilotica subsp. indica (Bavar), Prosopis cineraria (Kandho), and Salvadora persica (Kharijar). Some of the locally highly preferred grass species were also considered to be declining in the local environs; they included Dichanthium annulatum (Jinjvo), Cenchrus ciliaris (Dhaman), Sporobolus fertilis (Khevai) and Chloris barbata (Siyarpuchha). The study furthermore identified a close coincidence between the interest in conserving tree species diversity nearby the natural water resources and priorities of local inhabitants, which included protection of plenty of large trees (including many fruit tress, viz. Mangifera indicia (Ambo), Cordia dichotoma (Gunda)and Pithecellobium dulce (Gorasamli)), improvement of woody fodder tree and grass species regeneration, and reduction of overgrazing pressure on grasslands. Focusing management strategies on increasing the populations of such declining and highly preferred tree and grass species, by active restoration and grazing policies, would enhance the natural resource value and biodiversity wealth considerably and thereby the quality of life for the local inhabitants. The implications of the results are discussed and recommendations are suggested for conservation, management, and sustainable utilization of the fragile grassland ecosystem of the Banni region.

Ecological practice is telling us that to identify Nature’s rules, we should look for regularities in the resulting effects. Hidden rules are involved and the effects are manifested by compositional, functional, and structural transitions. This paper’s focus is on two conjectures regarding the governance of specific transition components, the first supposedly under global co-ordination, and the second under superimposed site specific instability oscillations. The reality of any apparent regularity in these is the sole condition for the regularity’s acceptance as a rule. Reality is testable but in retrospect only, based on time series analyses. Since long pollen spectra supply the evidence, the time period involved is measured in thousands of years. For maximal usefulness, a spectrum should have a long period length, dated horizons intensely sampled at short time steps, and precisely identified taxa. Period length and time step width matter because both may have a masking effect on the regularities. There is, of course, a natural limit for period length, which is set by the age of the pollen bearing sediments. We completed the analysis of 23 spectra using techniques deemed suitable for testing the conjectures. The spectra originated from sites in the Americas where we found suitable spectra in sufficient numbers and in geographic contiguity from the Arctic region to the Antarctic. The presented results have clear indications that the two conjectures identify real rules. The main body of the paper narrates the analyses and provides explanations. Informative materials, too voluminous for inclusion in the paper, are made available on the Internet at URL: www.vegetationdynamics.com linking to “Appendices Ta”.

The tadpole shrimp, Triops sinensis, was discovered in the paddy fields of the Shouchang River watershed. The gut contents of the shrimp from these field populations were analyzed in order to quantify their dietary patterns. Some species of tadpole shrimps were found to prey on mosquito larvae as well as uproot weeds. Mosquito larvae and weeds were seldom found in the paddy fields which the tadpole shrimp inhabited in the Shouchang River watershed. The results further showed that the larvae of these tadpole shrimp mainly feed on algae and rice lamina. The tadpole shrimp could feed on animal food including protozoa, nematodes, rotifers, crustaceans, and aquatic insect larvae, though the animal food was subsidiary.

Quantitative data are essential to an appropriate characterization of vegetation. In the past few years, considerable attention has been paid to vegetation sampling techniques. A number of methods have been developed for plant density estimations that utilize spacing distances instead of fixed-area quadrats. In this paper, we review the main distance methods for estimating density and propose a new distance method denominated the quartered neighbor method. In this method, the sampling point is considered the center, and the area around it is divided into four quadrants. The distance from the closest individual in each quadrant to its closest neighbor in the same quadrant is measured, and the average of them is the distance we need. It is actually an integration of two old distance methods, the nearest neighbor method, and the point-centered quarter method. With our new method and an old distance method (the point-centered quarter method), we calculated the average spacing distances of the Larix principis-rupprechtii population in the larch forests of the Donglingshan Mountain. Comparing the two methods with the quadrat method, we found they were almost the same in accuracy, but the precision of the new one was better. Meanwhile, it is adequate in sampling intensity and adaptable for general use in rapid ecological survey work.

Mangroves are unique intertidal halophyte formations growing in sheltered tropical and subtropical coastal areas. Due to the increasing population and economic development, mangroves have faced degradation and loss, which has been mainly caused by land conversion into aquaculture ponds in Asia. In the past several decades, the rapid growth of aquaculture has induced water pollution. Using mangroves for effluent treatment from coastal aquaculture ponds could be a suitable approach for wastewater treatment and healthy aquaculture development. An Integrated Mangrove-Aquaculture System (IMAS) was established to test whether the idea of a mangrove in situ treatment for aquaculture wastewater is feasible. The monocultures of three mangroves, Sonneratia caseolaris, Kandelia obovata, and Aegiceras corniculatum were established with area proportions of 45%, 30%, or 15%, respectively. One control pond without mangroves was also set up. The results indicated that the mangroves had different tolerabilities to long-term inundation. The aquaculture ponds had different fishery yields, considering the mangrove species and area proportions. The water quality of most of the experimental ponds was better than the control pond, except for the planted Sonneratia. It is concluded that mangroves can reduce the concentration of dissolved inorganic nitrogen and phosphate, buffer the pH value and increase the concertration of dissolved oxygen in aquaculture water bodies effectively. It is suggested to use 15% of the Aegiceras corniculatum area to conduct in situ purification of aquaculture wastewater and to enhance aquaculture production.