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1.
During summer 2005/2006, we characterized three sampling sites on mineral soils and four on ornithogenic soils from Cierva
Point, Antarctic Peninsula, in terms of topographic and abiotic features (altitude, slope, magnetic direction, temperature,
texture, pH, conductivity, organic matter, moisture and nutrient concentrations), and compared their microalgal communities
through taxonomic composition, species richness, diversity, chlorophyll a content and their variation in time. Average values of pH, moisture, organic matter and nutrient concentrations were always
significantly lower in mineral than in ornithogenic soils. Low N/P mass ratio showed potential N-limitation of biomass capacity
in the former. On the other hand, the results suggested that physical stability is not as a key stress factor for mineral
soil microalgae. Chlorophyll a concentration was not only higher in ornithogenic soils, but it also showed a wider range of values. As this parameter was
positively correlated with temperature, pH, nutrients, organic matter and moisture, we cannot come to conclusions regarding
the influence of each factor on algal growth. Communities of mineral soils were significantly more diverse than those of enriched
ornithogenic soils due to higher species richness as well as higher equitability. Also, their structure was steadier over
time, as shown by a cluster analysis based on relative frequency of algal taxa. Although Cyanobacteria and Bacillariophyceae
dominated almost all samples, Chlorophyceae represented 34% of the 140 taxa recorded, and most of them observed only in cultures.
The detection under controlled conditions of a high latent species richness in harsh mineral soil sites shows that the composition
and equitability of these microalgal communities would be more prone to modification due to the manifold local consequences
of climatic change than those of ornithogenic soils. 相似文献
2.
不同种植年限香榧根际土壤微生物多样性 总被引:3,自引:0,他引:3
为探明不同种植年限对香榧根际土壤微生物群落特征的影响,采用高通量测序技术,分析种植5 a、10 a和15 a香榧根际土壤细菌、真菌的群落结构和多样性特征.结果表明: 在种植15 a的香榧土壤中细菌Chao1指数、ACE指数和Shannon指数显著降低,Simpson指数无显著变化.NMDS分析显示,种植年限对细菌群落结构变化有显著影响,而种植5 a和10 a香榧林地土壤具有相似的细菌群落.细菌相对丰度、多样性以及群落结构(基本上由变形菌、放线菌、酸杆菌和绿弯菌组成)的变化与有机质、C/N、全氮呈极显著相关.香榧根际土壤真菌Chao1指数和ACE指数随种植年限的增加显著降低,Shannon指数和Simpson指数在种植10 a香榧林地中较高.真菌NMDS分析显示,相同种植年限土壤真菌群落聚在一起,不同种植年限之间能明显分开.真菌优势菌群主要包括子囊菌门、担子菌门、接合菌门.有机质是影响真菌丰富度、多样性和群落结构变化的主要因子.综上,香榧根际土壤微生物群落随种植年限不同而发生明显变化,种植年限、C/N、土壤全氮和有机质含量是影响香榧根际土壤微生物群落结构的主要因子. 相似文献
3.
研究生物多样性对季节的响应对于维持生态系统稳定、保护生物多样性、解析群落构建机制具有重要意义。本文以博斯腾湖湖滨湿地为研究对象,探究不同季节植物群落的物种多样性与功能多样性的变化规律。结果显示:(1)物种多样性指数随季节变化没有显著改变;功能多样性指数中,功能丰富度由春季到夏季逐渐减小,功能离散度逐渐增大;不同季节的功能均匀度差异性不显著;(2)植物功能性状在不同季节间差异显著;春季叶绿素含量显著低于夏季;夏季比叶面积和叶干物质含量显著高于秋季;叶片含水量和厚度由春季到秋季呈递增趋势;(3)影响Pielou指数和功能丰富度的主要环境因子分别为土壤铵态氮和速效磷;影响Shannon-Wiener指数、Simpson指数和功能均匀度的主要环境因子为土壤有机质;影响功能离散度的主要环境因子为土壤含水量;(4)影响最大株高的主要环境因子为土壤pH值;影响叶干物质含量的主要环境因子为土壤速效钾;影响叶片厚度和比叶面积的主要环境因子为土壤总磷;而影响叶片含水量的主要环境因子为土壤硝态氮;叶绿素含量与土壤因子无显著相关关系。 相似文献
4.
Coastal barrens in Nova Scotia are heathlands characterised by short, predominantly ericaceous vegetation, sparse tree cover,
exposed bedrock, pockets of Sphagnum bog, and stressful climatic conditions. Although coastal barrens are prominent in the physical and cultural landscape, they
are largely unprotected. We selected six barrens along the Atlantic coast, and surveyed 20 1-m2 plots at each barren for vascular plants, macrolichens, mosses and environmental factors. We recorded 173 species (105 vascular,
41 macrolichen, 27 moss), including six provincially rare vascular species found predominantly in nearshore areas with high
levels of substrate salt and nutrients, variable substrate depth, and short vegetation. Although vascular plant and moss richness
were similarly correlated with vegetation height, substrate depth, organic matter content, and rock exposure, there were no
clear correlations between vascular plant, macrolichen and moss richness across all sites. Vascular plant rarity and species
richness were not correlated, but had inverse relationships with key environmental gradients. Tailoring conservation efforts
to protect areas of high richness may thus mean that rare species are missed, and vice versa. Ordination and ANOSIM show that
barrens vegetation differs widely among sites; therefore, protecting any singular coastal barren will not protect the entire
range of vegetation communities and species in this heathland type. Conservation planning should emphasize protecting environmental
gradients correlated with richness, rarity and plant community structure, including substrate depth and moisture, and vegetation
height. Additionally, protected areas should include a coastal-inland gradient and a diversity of substrate types, including
exposed rock and trees. 相似文献
5.
Natural moisture limitation during summer drought can constitute a stress for microbial communities in soil. Given globally predicted increases in drought frequency, there is an urgent need for a greater understanding of the effects of drought events on soil microbial processes. Using a long-term field-scale drought manipulation experiment at Clocaenog, Wales, UK, we analysed fungal community dynamics, using internal transcribed spacer-denaturing gradient gel electrophoresis (DGGE), over a 1-year period in the 6th year of drought manipulation. Ambient seasonality was found to be the dominant factor driving variation in fungal community dynamics. The summer drought manipulation resulted in a significant decline in the abundance of dominant fungal species, both independently of, and in interaction with, this seasonal variation. Furthermore, soil moisture was significantly correlated with the changes in fungal diversity over the drought manipulation period. While the relationship between species diversity and functional diversity remains equivocal, phenol oxidase activity was decreased by the summer drought conditions and there was a significant correlation with the decline of DGGE band richness among the most dominant fungal species during the drought season. Climatically driven events such as droughts may have significant implications for fungal community diversity and therefore, have the potential to interfere with crucial ecosystem processes, such as organic matter decomposition. 相似文献
6.
Spatial heterogeneity of soil nutrients and plant species in herb-dominated communities of contrasting land use 总被引:1,自引:0,他引:1
Recent interest in spatial pattern in terrestrial ecosystems has come from an awareness of the intimate relationship between
spatial heterogeneity of soil resources and maintenance of plant species diversity. Soil and vegetation can vary spatially
in response to several state factors of the system. In this study, we examined fine-scale spatial variability of soil nutrients
and vascular plant species in contrasting herb-dominated communities (a pasture and an old field) to determine degree of spatial
dependence among soil variables and plant community characteristics within these communities by sampling at 1-m intervals.
Each site was divided into 25 1-m2 plots. Mineral soil was sampled (2-cm diameter, 5-cm depth) from each of four 0.25-m2 quarters and combined into a single composite sample per plot. Soil organic matter was measured as loss-on-ignition. Extractable
NH4 and NO3 were determined before and after laboratory incubation (28 days at 27°C) to determine potential net N mineralization and
nitrification. Cations were analyzed using inductively coupled plasma emission spectrometry. Vegetation was assessed using
estimated percent cover. Most soil and plant variables exhibited sharp contrasts between pasture and old-field sites, with
the old field having significantly higher net N mineralization/nitrification, pH, Ca, Mg, Al, plant cover, and species diversity,
richness, and evenness. Multiple regressions revealed that all plant variables (species diversity, richness, evenness, and
cover) were significantly related to soil characteristics (available nitrogen, organic matter, moisture, pH, Ca, and Mg) in
the pasture; in the old field only cover was significantly related to soil characteristics (organic matter and moisture).
Both sites contrasted sharply with respect to spatial pattern of soil variables, with the old field exhibiting a higher degree
of spatial dependence. These results demonstrate that land-use practices can exert profound influence on spatial heterogeneity
of both soil properties and vegetation in herb-dominated communities. 相似文献
7.
了解群落构建过程是生态学的核心和基本问题,这对于解释物种共存和物种多样性的维持,完善生物多样性保护政策至关重要。与传统的物种多样性相比,功能和谱系多样性能够提供更多的信息,特别是在群落构建过程方面提供深刻见解。2014年5月—2017年1月,采用样线法对澳门地区5个城市栖息地斑块中(生态一区、鹭鸟林、赛马场滩涂、关闸口岸滩涂和莲花桥侧红树林)的鸟类进行繁殖季和越冬季的调查,共调查14次。利用鸟类丰富度和多度来表征群落的物种多样性,其中多度以最大值保留法计;功能和谱系多样性分别采用功能丰富度(functional richness:FRic)和Faith’PD。同时,利用基于多度加权的平均成对功能距离(mean pairwise functional distance,MFD)和平均成对谱系距离(mean pairwise phylogenetic distance,MPD)来表征群落的功能和谱系结构。结果表明:共记录98种鸟类,隶属于14目32科,目、科、种中数量最多的依次为,雀形目鸟类最多为47种,鹭科物种数为11种,白鹭多度为849只;鸟类物种丰富度(68种)和PD在生态一区最高,... 相似文献
8.
三江源地区不同建植期人工草地植被特征及其与土壤特征的关系 总被引:14,自引:0,他引:14
研究了三江源地区不同建植期人工草地群落生物量、物种组成、多样性指数和土壤理化特征,并用多元逐步回归分析法探讨了土壤理化特征对群落生物量、多样性变化的响应.结果表明:研究区不同建植期人工草地植物群落的种类组成、植物功能群组成和群落数量特征存在显著差异;土壤含水量随着物种多样性指数的增加而增加,土壤容重随着物种多样性的增加而减小;土壤微生物生物量碳与土壤含水量、土壤有机质呈极显著正相关,与土壤容重呈极显著负相关;土壤有机碳含量明显呈"V"字型变化,且与土壤含水量的变化趋势相一致,随土壤容重的增加而减少;群落生物量与土壤养分和土壤含水量之间呈显著正相关,群落地上、地下生物量的增加有利于提高土壤养分含量. 相似文献
9.
Biotic and Abiotic Properties Mediating Plant Diversity Effects on Soil Microbial Communities in an Experimental Grassland 总被引:1,自引:0,他引:1
Markus Lange Maike Habekost Nico Eisenhauer Christiane Roscher Holger Bessler Christof Engels Yvonne Oelmann Stefan Scheu Wolfgang Wilcke Ernst-Detlef Schulze Gerd Gleixner 《PloS one》2014,9(5)
Plant diversity drives changes in the soil microbial community which may result in alterations in ecosystem functions. However, the governing factors between the composition of soil microbial communities and plant diversity are not well understood. We investigated the impact of plant diversity (plant species richness and functional group richness) and plant functional group identity on soil microbial biomass and soil microbial community structure in experimental grassland ecosystems. Total microbial biomass and community structure were determined by phospholipid fatty acid (PLFA) analysis. The diversity gradient covered 1, 2, 4, 8, 16 and 60 plant species and 1, 2, 3 and 4 plant functional groups (grasses, legumes, small herbs and tall herbs). In May 2007, soil samples were taken from experimental plots and from nearby fields and meadows. Beside soil texture, plant species richness was the main driver of soil microbial biomass. Structural equation modeling revealed that the positive plant diversity effect was mainly mediated by higher leaf area index resulting in higher soil moisture in the top soil layer. The fungal-to-bacterial biomass ratio was positively affected by plant functional group richness and negatively by the presence of legumes. Bacteria were more closely related to abiotic differences caused by plant diversity, while fungi were more affected by plant-derived organic matter inputs. We found diverse plant communities promoted faster transition of soil microbial communities typical for arable land towards grassland communities. Although some mechanisms underlying the plant diversity effect on soil microorganisms could be identified, future studies have to determine plant traits shaping soil microbial community structure. We suspect differences in root traits among different plant communities, such as root turnover rates and chemical composition of root exudates, to structure soil microbial communities. 相似文献
10.
Sini Savilaakso Jenny Koivisto† Timo O. Veteli Heikki Roininen 《Diversity & distributions》2009,15(2):356-365
Aim We aim to assess the impact of forest fragmentation on lepidopteran larval community and study the associations of microclimate and tree community with lepidopteran assemblage.
Location Kibale National Park, Uganda.
Methods We investigated the effects of forest fragmentation on leaf herbivory, density of lepidopteran caterpillars, species richness and diversity as well as the composition of herbivorous lepidopteran larval community. Microclimate, size of the fragment, distance to the continuous forest, and tree diversity were studied as possible explanatory factors. We sampled 10 Neoboutonia macrocalyx Pax. (Euphorbiaceae) trees in each fragment during dry and rainy season, total of four times, in a year to cover the seasonal variation.
Results The rates of herbivory, total larval density and species richness were significantly lower in the forest fragments than in the continuous forest but species diversity expressed as Fisher's alpha did not differ. The dominance structure and community composition of the larval communities in the fragments was different from that of the continuous forest. None of the differences we observed were related to the fragment area or distance to the continuous forest. Instead, we found an indication of association between the herbivore and the tree communities. The fragments had significantly lower humidity during most of the day and higher temperature during the afternoons (14–17 h), which might partially explain the differences in lepidopteran larval communities.
Main conclusions Decreased larval density and species richness as well as differences in the community composition and structure all highlight the importance of large continuous forest areas for maintaining larval biodiversity. 相似文献
Location Kibale National Park, Uganda.
Methods We investigated the effects of forest fragmentation on leaf herbivory, density of lepidopteran caterpillars, species richness and diversity as well as the composition of herbivorous lepidopteran larval community. Microclimate, size of the fragment, distance to the continuous forest, and tree diversity were studied as possible explanatory factors. We sampled 10 Neoboutonia macrocalyx Pax. (Euphorbiaceae) trees in each fragment during dry and rainy season, total of four times, in a year to cover the seasonal variation.
Results The rates of herbivory, total larval density and species richness were significantly lower in the forest fragments than in the continuous forest but species diversity expressed as Fisher's alpha did not differ. The dominance structure and community composition of the larval communities in the fragments was different from that of the continuous forest. None of the differences we observed were related to the fragment area or distance to the continuous forest. Instead, we found an indication of association between the herbivore and the tree communities. The fragments had significantly lower humidity during most of the day and higher temperature during the afternoons (14–17 h), which might partially explain the differences in lepidopteran larval communities.
Main conclusions Decreased larval density and species richness as well as differences in the community composition and structure all highlight the importance of large continuous forest areas for maintaining larval biodiversity. 相似文献
11.
M.A. El-Demerdash 《植被学杂志》1996,7(1):81-88
Abstract. Classification of the vegetation of the Farasān Islands using TWINSPAN technique resulted in the recognition of seven community types associated with seven different habitat types: silty runnels, palm orchards, rocky plains, rocky plateau crevices, coastal sand dunes, sand plains, and mangroves. These communities were dominated or co-dominated by 13 perennial species; 87 associate species were recorded in the study area with chamaephytes dominating the life-form spectrum. Canonical Correspondence Analysis (CCA) indicated that organic carbon, soil moisture, silt, electrical conductivity and calcium carbonate were the major edaphic gradients controlling the distribution of the plant communities on the Farasān Islands. Higher species richness was recorded in the plant communities inhabiting the palm orchards, the crevices of the rocky plateau, silty runnels, rocky plains and rocky plateau, while those of the mangrove and sand formations (dunes and plains) showed a lower species richness. Soil texture and organic matter are the main factors promoting species diversity in the more diversified habitats, while high salinity and calcium carbonate are the main factors associated with lower species diversity in the less diversified habitats of the study area. 相似文献
12.
13.
Benthic invertebrate communities within confluence sites, or areas of sediment deposition, are shaped by the input of catchment products including coarse woody debris, organic and inorganic particulates, and contaminants, but these sites also appear to be potential “hotspots” where recolonization of severely damaged ecosystems begins. Two species of leaf packs and a sweep netting technique were used to assess benthic invertebrate communities across a gradient of 14 confluence sites in 3 recovering lakes near the copper and nickel smelters in Sudbury, Canada. Environmental variables including delta habitat composition, delta area and length, and composition of deposited materials were used to detect spatial patterns in littoral benthic invertebrate communities. Benthic invertebrate community relationships with water chemistry were also assessed. Partial redundancy analysis (pRDA) showed that all sampling methods detected similar gradients of increasing invertebrate community richness and diversity as area and length of the sediment delta and the surface organic matter abundance increased. Two-way nested ANOVAs showed significant differences (p < .05) in taxa richness and diversity metrics among sites. Of the three methods, the benthic invertebrate community measurements from the birch leaf packs provided the strongest correlations with measures of organic matter inputs or habitat characteristics of the confluence zones. These correlations suggest that tree planting in riparian areas, or organic matter or macrophyte additions to littoral zones, may enhance littoral benthic invertebrate richness and diversity in acid and metal damaged lakes. 相似文献
14.
Abstract. The spatial organization of Mediterranean grassland in Spain is described, based on samples from 71 sites covering the existing variation in slope exposition and inclination.The whole set can be regarded as representing a trophic gradient, along which gradual variation in soil, species composition, biomass, and coverage were quantified. Corresponding to other studies from varying habitats, maximal species richness, diversity, and heterogeneity were observed on moderately infertile sites. Maximum species richness, over 60 species, occurred on sites with biomass values from 150–350 g / m2. Species richness values are much higher and biomass values are much lower than those found in temperate grasslands. The decrease in diversity towards the mosteutrophic communities is stronger than expected, but can be easily explained by the high grazing pressure here. The variation in diversity observed runs parallel with that in heterogeneity. Zones with a high species richness also have a high heterogeneity, meaning a low amount of dominance. Grazing is understood as abiotic form of disturbance. Differences in grazing pressure may modify the relation between richness and fertility. While the greatest grazing pressure coincides with the most eutrophic communities, decreasing progressively towards the oligotrophic ones, the trend predicted by the resource availability theory is maintained; species diversity will be maximal at intermediate levels of disturbance. Absence of grazing in the eutrophic communities would lead to an investment in the soil of the unconsumed organic matter. 相似文献
15.
Colin J. Yates Todd Robinson Grant W. Wardell‐Johnson Gunnar Keppel Stephen D. Hopper Antonius G. T. Schut Margaret Byrne 《Ecology and evolution》2019,9(13):7660-7675
Determining patterns of plant diversity on granite inselbergs is an important task for conservation biogeography due to mounting threats. However, beyond the tropics there are relatively few quantitative studies of floristic diversity, or consideration of these patterns and their environmental, biogeographic, and historical correlates for conservation. We sought to contribute broader understanding of global patterns of species diversity on granite inselbergs and inform biodiversity conservation in the globally significant Southwest Australian Floristic Region (SWAFR). We surveyed floristics from 16 inselbergs (478 plots) across the climate gradient of the SWAFR stratified into three major habitats on each outcrop. We recorded 1,060 species from 92 families. At the plot level, local soil and topographic variables affecting aridity were correlated with species richness in herbaceous (HO) and woody vegetation (WO) of soil‐filled depressions, but not in woody vegetation on deeper soils at the base of outcrops (WOB). At the outcrop level, bioclimatic variables affecting aridity were correlated with species richness in two habitats (WO and WOB) but, contrary to predictions from island biogeography, were not correlated with inselberg area and isolation in any of the three habitats. Species turnover in each of the three habitats was also influenced by aridity, being correlated with bioclimatic variables and with interplot geographic distance, and for HO and WO habitats with local site variables. At the outcrop level, species replacement was the dominant component of species turnover in each of the three habitats, consistent with expectations for long‐term stable landscapes. Our results therefore highlight high species diversity and turnover associated with granite outcrop flora. Hence, effective conservation strategies will need to focus on protecting multiple inselbergs across the entire climate gradient of the region. 相似文献
16.
The arbuscular mycorrhizal fungal (AMF) communities associated with cacao in Venezuela were studied. The species of AMF spores present in sixteen cacao plantations and in one nursery were isolated and identified when possible. The spore densities, species richness, diversity, Shannon-Wiener diversity index and dominance concentration index for the AMF communities were calculated. Acaulospora scrobiculata was associated with cacao plants in all study sites. No Scutellospora spp. were found in the analyzed soils. The spore number found in cacao plantations was relatively lower as compared with other tropical crops (38 spores 100 g–1 soil up to 1674). Soils that were cultivated with cacao for more than 40 years showed the lowest spore numbers. Species richness and diversity of AMF communities associated with cacao, were negatively correlated with available P in soils. The Shannon-Wiener diversity index was positively correlated with soil organic matter. These results indicate that the traditional cacao cultivation practices used in Venezuela, maintain mycorrhizal infection on cacao plants. The diversity of the AMF community is similar to that found in natural undisturbed ecosystems from Venezuela. 相似文献
17.
Gilles Houle 《American journal of botany》1990,77(11):1433-1439
The species-area relationship and its underlying explanatory mechanisms were investigated in a primary successional sere on a southeastern (United States) granite outcrop. There, plant communities occupy soil-filled depressions separated from one another by areas of bare rock. They have been termed “island communities.” Soil depth and area increase as succession proceeds from Sedum smallii, to lichen-annual, to annual-perennial, and to herb-shrub-tree stages. Although plant species richness is significantly and positively correlated with island area in the system studied (all successional stages considered), the relationship between species richness and island maximum soil depth is stronger. However, island maximum soil depth and area are significantly and positively correlated. The exponential function describes the speciesarea relationship better than the transformed power function. Within successional stage, species richness shows no significant relationship with area or depth, except for late-successional island communities. Processes related to community successional development may explain the species-area relationship that exists when islands of all stages are considered. However, mechanisms related to equilibrium between extinction and immigration may be responsible for the speciesarea relationship for late-successional island communities. 相似文献
18.
Fredrik Dalerum Tarryn Anne Retief Carl Peter Havemann Christian T. Chimimba Berndt Janse van Rensburg 《Ecology and evolution》2019,9(1):154-165
Studies of biodiversity along environmental gradients provide information on how ecological communities change in response to biotic and abiotic factors. For instance, distance to water is associated with several factors that shape the structure and the functioning of ecosystems at a range of spatial scales. We investigated the influence of distance to a perennial water source on ant communities in a semi‐arid savanna in northern Botswana. Ant abundance, taxonomic richness, and both alpha and beta diversity were generally higher during the wet than the dry season. However, there were strong seasonal influences on the effects of distance to water, with more pronounced effects during the wet season. While both abundance and beta diversity declined with increasing distances to water during the wet season, there was a contrasting increase in alpha diversity. There was no major effect of distance to water on taxonomic richness during either season. Beta diversity was as high across as along gradients, and we found support for modular rather than nested community structures along gradients. Our study demonstrated that small‐scale gradients in distance to water can influence several aspects of ant communities in semi‐arid savannas. However, our results also point to strong effects of small‐scale environmental variation, for instance associated with vegetation characteristics, soil properties, and plant community structure that are not directly linked to water access. 相似文献
19.
艾比湖湿地芦苇根际土壤氨氧化古菌的多样性和群落结构 总被引:1,自引:0,他引:1
【目的】旨在揭示耐盐植物芦苇根际与非根际土壤AOA群落结构间的差异,为深入研究盐生植物根际土壤微生物与耐盐性之间的关系提供理论基础。【方法】应用高通量测序技术以氨单加氧酶基因(amoA)为分子标记,对新疆艾比湖湿地荒漠生态系统不同季节(春、夏、秋)芦苇根际与非根际土壤氨氧化古菌(AOA)的多样性和群落结构进行研究。【结果】结果表明,不同季节芦苇根际土壤AOA多样性和丰富度存在差异,相比非根际土壤,夏季和秋季芦苇根际土壤AOA多样性较低丰富度较高,春季多样性较高丰富度较低。芦苇根际土壤中AOA的多样性为春季夏季秋季。AOA群落组成分析表明,土壤样品中AOA群落主要集中在泉古菌门(Crenarchaeota)和奇古菌门(Thaumarchaeota),其中泉古菌门为主要优势菌门。RDA分析表明,含水量(SM)、有机质(SOM)、总氮(TN)和pH是影响芦苇根际土壤AOA群落多样性和丰富度的主要环境因子。【结论】不同季节芦苇根际土壤AOA多样性及丰富度存在差异,相比非根际土壤,芦苇根际土壤AOA更丰富。 相似文献
20.
The maintenance of invertebrate diversity within agricultural environments can enhance a number of agronomically important
processes, such as nutrient cycling and biological pest control. However, few Australian studies have been undertaken which
specifically address the effects of commercial management regimes on rice field biodiversity. In this study, we compared aquatic
macroinvertebrate communities within Australian rice fields cultivated under three commercial management regimes: conventional-aerial
(agrochemicals applied, aerially sown), conventional-drill (agrochemicals applied, directly drill-sown) and organic-drill
(agrochemical-free, directly drill-sown). These comparisons were undertaken using a combination of community assessment approaches,
including morphospecies richness, abundance, diversity and community composition. In general, greater biodiversity existed
within macroinvertebrate communities that developed under organic management regimes than under conventional regimes (i.e.,
higher morphospecies richness and Shannon diversity). Although there were significant differences in several parameters across
management regimes early in the rice-growing season, as the growing season progressed the invertebrate communities that developed
in the different management regimes became more similar. Only community composition analyses showed significant differences
late in the growing season, with functional differences across aquatic faunal assemblages suggested by increased predator
abundance in communities sampled from the organic management regime. In order to improve biodiversity within these aquatic
environments, management techniques need to be examined individually and the most disruptive processes identified. Alternative
management procedures can then be developed that minimise biodiversity loss whilst still delivering required agronomic outcomes. 相似文献