grows in extremely arid areas and is a dominant species of desert riparian forests in the lower reaches of the Tarim River. Using a single factor control test with indoor potted plants, seedlings were treated with either salt or water stress, and compared to a control treatment. For salt stress, plants were treated with one of five salinity gradients: a control group with no salt stress (S0); light salt stress (S1); moderate salt stress (S2); middle, and high salt stress (S3); and high salt stress (S4). In addition, five moisture gradients were employed: groups D0, D1, D2, D3, and D5 (flooding), for which soil water contents were 75%, 55%, 35%, 15% field water capacity, and flooding, respectively. Combined treatments with both salt and water stress were not performed. The goal of the present study was to analyze the effects of salt and water stress on seedlings by measuring photosynthetic characteristics, anatomical structure, and morphological plasticity characteristics, such as height, crown breadth, epidermis, and changes to the cortex, vascular cylinder etc. Because structure provides the basis for function, the anatomical structure of desert plants can be indicative of their photochemical efficiency. The results showed that: 1) salt and water stress resulted in relatively lower growth rates, biomass, and smaller plant height and crown width of seedlings. In addition, the root to shoot biomass ratio initially increased and then decreased rapidly. Salt stress adversely affected seedling growth to a greater extent than water stress did ( assimilating shoots > leaf under salt stress, and leaf > root > assimilating branches under water stress. In summary, seedlings were better adapted to low levels of stress as observed in the S0 and D1 treatments. Compared to water stress, salt stress is a more critical ecological factor that is important to inhibition of the growth of seedlings.
Animal grazing in rangelands ecosystems is considered as one of the most influential factors in changing plants' biomass, dimensional characteristics and different aspects of ecosystem. Regarding the fact that species is one of the main dominated species of mountainous rangelands in the northwest of Iran, limited information is available concerning the influence of various grazing intensities on its structural properties, aerial biomass, and especially on its underground biomass. In order to this, the effects of different grazing intensities (low, moderate and high) on aerial and underground biomass and structural properties of this species are investigated. Accordingly, three rangeland areas with various grazing intensities were chosen and sixty 1 m plots were established along six, 100 m transects. Afterwards, structural properties, leaf litter, aerial and underground biomass of the species were measured in each of the areas. In order to compare the mean biomass and structural parameters of the plant in the three areas, one-way ANOVA and Duncan's multiple range tests were used. The results indicate that there is a significant difference between the quantity of investigated parameters (except for the area and diameter of the collar) of the studied species under three grazing intensities. The highest and lowest aerial biomass average in two places with low and high grazing intensities was 5.18 and 76.42 g, respectively. Moreover, the maximum average of underground biomass per plant (95.32 g) and its minimum amount (46.56 g) belong to low and high grazing intensities, respectively. Estimating the percentage of parameters' variations in areas with high and moderate grazing intensities in comparison to the area with low grazing intensity demonstrated that all the parameters had a decreasing trend and the maximum percentage of variations of this species is related to the high intensity grazing area. Generally, by increasing grazing intensity, the decrease in collar diameter and plant cover was the lowest and for the characteristics of leaf litter, underground and aerial biomass was the highest.
Salinity is a worldwide problem, occurring in all climatic regions. is a diverse riparian species, which survives in saline environments, and have numerous adaptation capacities to combat salinity stress. In this review, we collected available research information about the effect of salinity on its physiology, morphology, anatomy with relation to hydraulic traits. The information showed that can progressively tolerate high salinity stress by changing its stomatal aperture, activities of antioxidant, xylem anatomy and hydraulic conductivity. It can be a good option for afforestation and reclamation of salinized lands, which may be an option for increasing the production of feed stocks for non-food goods, and positive impact on climate.
Exploring the underlying mechanisms of community diversity is a key issue in ecology and conservation biology. Community diversity studies typically focus on local processes, but these factors cannot completely explain community diversity. Many previous studies have shown that species richness can be quite different among communities with similar habitats. Therefore, the importance of regional processes has gradually been considered, and many hypotheses based on regional processes have been proposed. The species pool hypothesis developed by Zobel et al. is one of the most important theoretical developments in the field of community diversity. The species pool hypothesis suggests that community diversity is not only associated with contemporary environmental factors and local ecological processes (e.g., competition, predation, resources, spread, and interference), but is also limited by the regional species pool. The regional species pool is the set of species in a certain region that are capable of coexisting in a target community, which is shaped by historical (e.g., glaciation and geological age) and regional processes (e.g., speciation, immigration, dispersion, and extinction). To explore the applicability of the species pool hypothesis to community diversity in the Inner Mongolia grassland, we investigated the species diversity in the grassland region from late July to mid-August in 2012, when the grassland community biomass was at its peak. In this region, precipitation is considered the most important environmental factor affecting species diversity. Therefore, we established 192 field sites in the Inner Mongolia grassland along a gradient of mean annual precipitation. The position of each field site was located using GPS. At each site, an area of 10 m × 10 m was delineated, and 10 plots of 1 m × 1 m were randomly placed in the delineated area to survey all plant species. Based on these data, the relationships between regional diversity (gamma diversity) and community diversity (alpha diversity) were analyzed along seven mean annual precipitation (MAP) gradients. Gamma diversity is the total species richness at a site. Alpha diversity is defined as the mean species richness (number) for the 10 plots at a site. The correlation coefficient between these two diversity indices was used to verify the applicability of the species pool hypothesis. A few key results were obtained. (1) Both alpha diversity and gamma diversity increased significantly with MAP in the Inner Mongolia grassland. (2) Gamma diversity and alpha diversity showed a significant positive linear relationship under different gradients of MAP, which reveals that the species pool hypothesis adequately explained community diversity along different precipitation gradients. (3) The effect of the regional species pool on community species diversity weakened as the MAP increased, which explains the decrease in the applicability of the species pool hypothesis as MAP increased. (4) Exploring the relationship between gamma diversity and alpha diversity represents an effective method for determining the impact of the species pool on community diversity. This study contributes to the theory regarding the mechanisms that maintain community diversity. It also has practical applications for the protection of diversity in the Inner Mongolia grassland.
A phyto-sociological and ecological study of naturally growing species and their conservational strategies is carried out in Dakshin Dinajpur district, West Bengal, India. The main objective of this work is to find out their ( . and . × ) natural distribution, density, abundance and the dominance along with associated species. A total of 50 (1 × 1 m ) quadrats were made at two study sites, each site contained 25 quadrats. Coexistence of almost 57 species of families with both study species of in two study sites indicates similar habitat preference of these species. Dicotyledon species were found maximum in all quadrat of the two study sites. Following the present biotic or abiotic threat as well as oblivious human activities to these species we propose here few possibilities for their conservation. The study will encourage ecologists, pharmacologists as well as biologists to do similar studies on various naturally growing important plants in this part of country.
The development of intensive agriculture has caused a decline in habitat variability and loss of biodiversity in the agro-landscapes of the world. To explore the relationships between landscape heterogeneity and soil meso- and microfaunal communities in typical agricultural landscapes, we established a study area in Fengqiu County, Henan Province, which is a typical agricultural region in the lower reaches of the Yellow River. We established different buffer radii (25 m, 50 m, 100 m, 150 m, 200 m, and 250 m) at the plot scale, based on a multi-scale (plot, habitat, and field) approach. We combined soil faunal diversity data from 31 sampling plots in the study area. We used the landscape index of CONTAJ as landscape index to determine landscape heterogeneity levels, including high, medium and low landscape heterogeneity. Moreover, at the habitat scale, we selected farmland and woodland in each plot as habitats. At the field scale, soil sampling rings and Tullgren funnels were used to obtain soil meso- and microfauna from the center and edge of the farmland and woodland habitats. In addition, the effects of scale on the diversity of soil meso- and microfauna were analyzed using a multivariable ANOVA at plot, habitat, and field scales. A total of 2300 soil faunal individuals belonging to 27 classes were identified. The dominant groups included Oribatida, Actinedida, and Formicidae. Hypogastruridae, Isotomidae, Poduridae, Diptera larvae, and Coleoptera larvae were common groups. The results indicated that different habitats and fields contained different species abundances of soil meso- and microfauna. For example, the center of farmland had the greatest species abundance of soil fauna, whereas the lowest abundance occurred in the center of the woodland. Furthermore, species diversity indices including species richness, Shannon index, and Simpson index were the highest at the edge of the farmland, but the lowest in the center of the woodland. Animal diversity in the soil indicated that, except for species richness, there were no significant differences among other diversity indices. The effects of habitat scale on the soil faunal communities were most significant among the three scales (plot, habitat, and field). Although there was no significant effect among different landscape heterogeneity levels at the plot scale, the effect of landscape heterogeneity index on the soil fauna was significant at the 25 m buffer radius. We concluded that although woodlands did not maintain soil meso- and microfauna diversity in study area, this habitat has important ecological values that require further study. Compared with farmland, woodland could provide better habitats for soil meso- and microfauna in the future. Therefore, it is important to reinforce the protection of woodlands in agricultural landscapes.
Large-scale land use changes have remarkably influenced the global carbon (C) and nitrogen (N) cycling. Soil microorganisms are known to be the key drivers of these processes and act as susceptive indicators of changes in ecosystem functioning due to land use changes. In forest ecosystems, differences in the stability and turnover of soil C and N pools are mainly associated with the variation in the above- and belowground litter/root inputs to the soil from the tree species. However, the impact of soil C and N pool differences caused by tree species on soil microbial community structure has not been fully investigated in subtropical China. This study aimed to assess the effects of tree species conversion from a coniferous to broad-leaved plantation on the soil microbial biomass and community structure associated with C and N transformations within the plant-soil system. The microbial biomass and composition (reflected by 28 phospholipid fatty acid profiles), soil C and N pools in the top soils, and C and N contents of certain litter and fine root profiles were measured 19 years after the reforestation of Chinese fir ( ) woodland with the same species or a native broadleaf species . The results suggested that soil microbial biomass was significantly higher in the than in the plantations, and non-metric multidimensional scaling ordination plots showed distinct patterns of soil microbial community structure between these two species. Soil microbial biomass showed negative correlations with litter N or mineral N content, i.e., ammonium N (NH -N) and nitrate N (NO -N), but was positively correlated with soil C content and litter C: N ratio. Further, there were negative correlations between soil microbial biomass C and mineral N pools. These results indicated that tree species transition from to might have improved the soil labile C and N pools and their availability, leading to an increase in the soil microbial biomass. Redundancy analysis conducted to elucidate the relationships between the microbial community and C or N parameters also showed that the soil C: N ratio, soil total N, and NH -N might be the major factors influencing the soil microbial community. However, soil microbial diversity and richness were not significantly altered by the tree species transition. These results suggested that the potential process rates mediated by litter-derived C and N availabilities might not always be accompanied by a remarkable response from community diversity, but might affect microbial biomass. In conclusion, long-term tree species transition from coniferous to broad-leaved plantations significantly improved soil C and N pools and their availabilities, thereby increasing the soil microbial biomass and changing the composition of in situ soil microbial community. Previous events (e.g., land use history) might have considerable long-lasting impacts on soil microbial diversity and richness than the contemporary environment variables caused by the tree species transition 19 years after reforestation.
Plant growth and development are usually influenced by salt, drought, high or low temperature, strong illumination and other adverse factors, which may finally threaten the settlement and propagation of the species. Studies on seed germination behavior and seedling growth of annual halophyte plant living in harsh environment can help us to thoroughly understand the tolerance mechanism of desert plants. , an annual halophyte living in extreme desert habitat, has special morphological structure and characteristics in tolerance of stress. In the present study, we discussed the effects of different stress conditions, such as light, day/night temperature variation, salt (NaCl) and drought (PEG 6000), etc. on seed germination (SG) and seedling growth (SGr) of Results showed that: (1) Light had a positive effect, while darkness had a negative effect on SG, which indicates that seed germination of depends on and is sensitive to light. (2) Monthly examination of SG from 2014 to 2015 showed that SG of seed without winged perianth (NWP) was apparently higher than seed with winged perianth (WWP) stored at room temperature (RT) or 4 °C. For WWP seeds, SG in light was significantly higher than that in darkness; SG also varied among seasons: in Spring, SG of seeds stored at RT was the lowest and so did it in summer with seeds stored at 4 °C. SG of seeds stored at both temperatures had no significant difference at the same month. Seed vigor agreed with SG behavior partly and there was no obvious difference between months. (3) The day/night temperature variation (D/NTV) applied significant effect on SG and SGr. SG decreased at lower D/NTV (e.g. 5 °C/15 °C) but increased at middle and higher D/NTV (e.g. 10 °C/20 °C, 15 °C/25 °C, 20 °C/30 °C) in light. In darkness, the SG decreased at higher D/NTV (e.g. 15 °C/25 °C, 20 °C/30 °C) but increased at lower and middle D/NTV (e.g. 5 °C/15 °C, 10 °C/20 °C). 10 °C/20 °C D/NTV had positive effect on SG in both light and darkness; germination rate was promoted at higher D/NTV in both light and darkness. SGr was promoted at lower D/NTV while inhibited at higher D/NTV. (4) SG at lower concentration of NaCl (< 100 mmol L , osmotic pressure (OP) ≥ − 500 kPa) and PEG (< 150 g L , OP ≥ − 300 kPa) was similar to the control (OP 0 kPa); however SG at higher concentration of NaCl (≥ 500 mmol L , OP < − 2478 kPa) and PEG (≥ 200 g L , OP < − 300 kPa) significantly decreased but still exceeded 35%, indicating that is salt- and drought-tolerant. When considered of the SG between NaCl and PEG treatment at the same level of OP, which was much better with NaCl than that with PEG. Taken together, we speculate that should employ ‘cautious strategy’ in germination, which means that under favorable conditions with light, temperature, water, etc., can germinate actively and get enough seedlings developing into adult plants; whereas under unfavorable conditions, the seeds may not germinate or germinate in a small amount to replenish soil seed bank.
Soil respiration is a key component of net CO exchange in grassland ecosystems and directly influences the soil carbon pool dynamics. While numerous soil respiration studies in grazed grasslands exist, the accurate quantification of the net CO exchange in grassland ecosystems throughout the entire year is required to determine whether grazed grasslands are carbon sinks or sources. In this study, we evaluated how stocking rate influenced soil respiration during the non-growing season in a typical grassland in the Hebei Province of North China. To examine the effects of stocking rate on soil respiration, soil respiration rates were measured using a soil greenhouse gas flux measurement system. Three stocking rates—ungrazed control (UG), moderate grazing (MG), and heavy grazing (HG)—were applied by grazing small tail sheep (ewes and lambs) at different densities from the end of June to early October in 2010 through 2013, and the relationships among soil respiration, stocking rate, and environmental factors were analyzed during the non-growing season (1 October 2013 to 30 April 2014). Variation in soil respiration followed a “V” pattern and was correlated with soil temperature and moisture for all stocking rates. Stocking rates did not significantly influence soil temperature or soil moisture; however, cumulative CO emissions during the non-growing season decreased dramatically ( MG (0.38 ± 0.012 kg C m ) > HG (0.33 ± 0.009 kg C m ). The influences of air and soil temperature on soil respiration rate were best described by an exponential equation (R = 0.43–0.55; < 0.01). A significant quadratic relationship was found between soil moisture and soil respiration rate (R = 0.46–0.67; < 0.01). Soil respiration during the non-growing season was most strongly influenced by air temperature (R = 0.56), with values either increasing or decreasing relative to the UG treatment for the MG and HG treatment, respectively. Given the strong influence of grazing intensity on soil respiration in this grassland ecosystem, we suggest that the accurate estimates of annual soil respiration should routinely account for soil respiration during the non-growing season.
In this study, the wet/bulk and dry atmospheric deposition of different inorganic nitrogen (N) species was investigated in the Fujian tobacco planting area from 2010 to 2014. Wet/bulk N deposition flux of inorganic N was monitored at five sites (Fuzhou, Shanghang, Changting, Taining, and Wuyishan) of Fujian by using precipitation gauges. While dry deposition fluxes of gaseous NH , NO , and HNO ( NH , NO , and HNO ), and particulate NH and NO ( NH and NO ) were estimated only at the Fuzhou site through multiplying monthly mean N concentrations obtained from DELTA (DEnuder for Long-Term Atmospheric sampling) system ( NH , HNO , NH , NO ) and passive samplers ( NO ) and the modeled monthly mean dry deposition velocities provided by the GEOS-Chem global chemical transport model. Annual mean NH -N, NO -N, and total inorganic N (TIN) concentrations in precipitation (rainwater and snow) were 0.21–1.05, 0.33–0.74, and 0.59–1.68 mg N L , respectively, and the averages over the monitoring period were 0.55, 0.49, and 1.04 mg N L , respectively. Across the five monitoring sites, the average annual wet/bulk N deposition was 17.6 kg N ha a , while that of NH -N and NO -N amounted to 9.2 and 8.4 kg N ha a , respectively. Wet/bulk deposition was lowest at Changting, but no significant differences were found between the other four sites. Annual mean atmospheric concentrations of NH , NO , HNO , NH , and NO were 1.87, 2.95, 0.45, 2.36, and 1.23 μg N m , respectively. Gaseous NH concentrations were highest in summer and lowest in winter. In contrast, seasonal fluctuations in other measured N species (e.g., NO ) were not as large as those of NH . The annual mean total dry deposition was estimated to be 9.6 kg N ha a , and those of the individual species, NH , NO , HNO , NH , and NO were estimated to be 4.1, 2.2, 2.0, 0.8, and 0.4 kg N ha a , respectively. Based on the similarities in wet deposition, if we assume a similar level of dry deposition at all the sites, the total (dry and wet) N deposition was 27.2 kg N ha a on average, which twice the critical load (10–15 kg N ha a ) for forest ecosystems, suggesting a risk of “N saturation” in the local natural environment.
In this study, the effect of used motor oil on the growth rate of three different species of aquatic macrophytes was investigated for a three week period under laboratory conditions. Three treatments were used in pots: high oil, low oil, and a control, each with three replicate buckets (three pots per bucket). The relative growth rate (RGR) of the tested plants, L., L., and L., differed significantly between treatments ( < 0.001, one-way ANOVA). In the control treatment, , and grew well and produced more lateral shoots than in the high and the low motor oil treatments. The longest shoot lengths were also greater for all three plants in the control than in the low and the high motor oil groups.
inhibits growth of plant pathogen and causes mortality of plant pests by producing lipopeptide biosurfactans. In this study secondary metabolites produced by mutant M419 was extracted and production of lipopeptide surfactants of the mutant was observed by hemolytic activity and oil spreading techniques. The effects of the biosurfactant on mortality of the first and second instars of Linnaeus was evaluated by leaves immersion method at 3600, 1800, 900, 450 and 0 mg/l concentrations in laboratory. The LC and LC values after 4 days of contact were measured 1172.145 mg/l and 3336.999 mg/l, respectively. Results indicated that, these values were 3.8-fold and 1.62-fold lower than that obtained after 2 and 3 days, respectively. The crude biosurfactant retained the larvicidal activity even when autoclaved at 121 °C for 15 min. M419 was able to inhibit considerably growth in a dual culture assay.
Theaceae is a plant family that mainly distributed in tropical or subtropical regions of Asia. Most species of Theaceae are endemic to China. Here, we used the herbarium collections aim to: a) detect the spatial species richness patterns; b) find out the geographical divisions and c) detect the environmental drivers of the dissimilarity patterns (β diversity). The current distributions of 193 Theaceae species were modeled using MaxEnt. Meanwhile, we calculated the pair wise dissimilarity between grid cell assemblages based on beta-sim index. An ordination was used to analyze the environmental drivers of the dissimilarity patterns. We found that the diversity hotspots for Theaceae species mainly locate in Fujian and Guangxi province. Two major divisions were suggested by the ordination analysis. The longitudinal division implies the climatic divergences between southeastern and southwestern China, while the latitudinal division implies the geographical barriers. For the species in southeastern China, the dissimilarity pattern is mainly driven by temperature annual range, annual precipitation and annual mean temperature. In the southwestern China, isothermality, precipitation seasonality and the rising altitude are the three main drivers. For effective conserving the Theaceae species, the protection of the micro-habitats and the high diversity areas on both sides of these divisions will be essential.
The present study was conducted in Doon valley of north western Himalaya to estimate biomass and carbon storage in male bamboo ( ) raised on degraded bouldary land Different non-linear models (Monomolicular, Logistic, Gompetz, Allometric, Rechards, Chapman) were fitted to the relationship between total biomass as dependent variable and diameter at breast height (DBH) as independent variable. The adjusted R values were > 0.85 for all the six models indicating that all models are apparently equally efficient. Allometric model (Y = × DBH ) was found to be best performing and was used for fitting different biomass components using DBH as explanatory variable. The estimated total aboveground biomass from the developed allometric model was 18.91 Mg ha in 6 year and 109.30 Mg ha in 20 years old plantation. Carbon content in different components revealed that it was higher in culm (48.66%) followed by branch (48.09%) and leaf (44.68%). The total biomass carbon stocks mitigated were 8.39 and 49.08 Mg ha in 6 and 20 year old plantations.
Conflict between human and wildlife takes place because of sharing and competition for limited resources. The conflicts become a controversial, if it is concerned with the livelihood and economic value. Protected Areas (PAs) worldwide are facing a problem, because of Human–Wildlife Conflict (HWC). The damages caused by wildlife have affected the day to day activities of people and there has been a query regarding the humanitarian value and wildlife welfare. The study was conducted in Chitwan National Park (CNP), Nepal, to find out the major losses caused by wildlife, especially, the mammals in the surrounding villages. The results showed that the main wildlife caused damages include crop depredation followed by livestock loss. Majority of the respondents i.e. 149 (89 males and 60 females) said that the main reasons for disliking wildlife is because they destroy crops and 10 males and 6 females stated that the reasons for disliking wildlife is because livestock depredation do occurs. As, the people living around the CNP mainly depend on agriculture and livestock farming for their survival, thus, wildlife activities have been a huge concern to them. The local people have been suffering from the huge economic losses by wildlife damages which have heightened the antagonistic behavior towards wildlife. And it has probably questioned on the conservation and management of wildlife in a long run. Though, there has been a global and national concern in making efforts not to overlook either of them but the query remains “How is it Possible?” so “Living with wildlife: Conflict or Coexistence” has remained a query without answer.
Nitrification and denitrification are the main contributors to soil N O production and emission, and distinguishing their contributions to N O emission under natural conditions is vital to deciphering nitrogen biogeochemistry. Stable isotopes have provided insight to resolve this problem, of which N O ( N abundance in N O), dual isotopes ( N, O) and site preference (SP) are the most effective methods currently. N O is useful in tracing substrates yielding N O, but it is helpless to make accurate differentiation between nitrification and denitrification; The dual isotopes, N and O, introduce O atom sources in partitioning N O source and this method could roughly apportion N O from nitrification and denitrification. However, expensive equipment requirements and the inherent uncertainties on O determination owning to few data available hamper its accuracy and applicability on distinguishing nitrification and denitrification. Site preference (SP) provides new insight on distinguishing contribution of nitrification and denitrification on N O emission and results in more accuracy results. We summarized that the average values of N O , O and SP during denitrification, which were − 29.29‰, 19.78‰, and 2.43‰, respectively, are much lower than the corresponding values during nitrification, which were − 7.87‰, 48.03‰ and24.14‰, respectively.
Geographic variation can lead to the changes of local plant species, which play crucial roles in primary production and ecosystem structure. Therefore, understanding multiple scale distribution patterns of plant species is important for us to effectively monitor ecosystem changes due to climate changes and other modifications. Here, we mainly investigated the distribution pattern of wood vascular plants and key environmental controlling forces in natural broadleaved forest along the latitudinal gradient across 24 geographic regions of China continental territory. The results showed that the richness and diversity of plant community significantly decreased with the increasing latitude. The similarity of plant community also decreased with increasing latitudinal distance. The mean annual precipitation and mean annual temperature played the most important roles in the distribution of plant community across latitudinal gradient, followed by soil pH and soil moisture.
Agro-drought risk analysis is helpful for improving the ability of regional disaster management and reducing potential drought risk under climate change. In this paper, we use daily meteorological observations from 60 stations and maize yield data in Southwest China during the period from 1961 to 2012. Based on natural disaster risk theory, maize drought risk assessment model is established from four factors: hazard, exposure, vulnerability, drought prevention and mitigation, and maize drought risk is zoned and analyzed in Southwest China under climate change. The results show that under climate warming, the high and sub high risk zones are decreased in Yunnan Province and emerged in central and northwest Sichuan Province, the low and sub low risk zones are largely reduced in Sichuan Province, Guizhou Province and Chongqing City, and the other increasing zones are mainly moderate risk zones. In summary, maize drought risk mainly depends on the maize drought hazard; the maize drought risk increases in the north and decreases in most of south under climate warming in Southwest China. Enhancing maize drought risk management helps to reduce the potential risk to agricultural production in southwest China under climate change.
World-wide wetlands are experiencing increasing pressure from economic development, including the conversion of wetlands to agriculture. While it is assumed that this land use change will have negative impacts on local biodiversity, the specific impacts of agriculture on insect biodiversity in wetland ecosystems are poorly understood. To address this knowledge gap we investigated insect communities in the multi-land use Wuxijiang National Wetland Park, quantifying both species diversity and functional diversity. Four species diversity indexes and twelve functional diversity indexes were used to describe species diversity and functional diversity respectively. We provide three primary results: 1.) Species diversity and functional diversity of natural wetland plants is not necessarily higher than artificial economic plants; 2.) Species diversity indexes are generally correlated with functional diversity indexes; and 3.) Straw mulch cultivation can increase the species diversity and functional diversity of insect.
Relationships between environmental factors and stem radius variation at short temporal scales can provide useful information regarding the sensitivity of tree species' productivity to climate change. In this study, we used automatic point dendrometers to continuously record day-to-day stem radius variations of two evergreen ( and Blanco) and two deciduous ( , var. ) broadleaves species growing in a tropical karst forest in Xishuangbanna, Yunnan, southwest China. Daily stem radius increments were extracted from dendrometer traces, and were correlated with environmental variables recorded from nearby standard meteorological stations. The results indicated that stem radial growth of the four species initiated from late dry season (middle April), speeded in rainy season (July to August) and slowed down after October. Daily stem radius increments of the four species correlated positively with relative humidity (RH) and rainfall (Rain), while correlated negatively with daily maximum temperatures (T ), vapor pressure deficit (VPD) and photosynthetic active radiation (PAR). Rainfall and moisture availability during early growth season (May–June) was important for stem radius growth of the four studied species. Stem radial growth rates of two deciduous species ( , var. ) declined significantly during short-term drought events occurred during late April and late May to early June, then recovered quickly after one or more rainfall events, which indicated a more sensitive response to climatic factors as compared with evergreen species. These results provide evidences for studying and predicting tree growths and forest productivities in the tropical karst forests under future climate change.