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1.
AbstractNative ants are the oldest example of biological control agents used in tropical tree crops. Unfortunately, intensification of agricultural practices has led to a simplification of habitat and subsequent loss of native ant biodiversity. This article describes research that evaluated the native and introduced ants present in the canopies of two Australian sun coffee plantations, their distribution pattern and their potential to limit pests. The presence in coffee plantations of a range of beneficial insects and parasites, plus the effect of ants, most notably Iridomyrmex suchieri Forel, may maintain potential pests at low levels in coffee plantations. These effects may be important for future biological control programs of coffee pests in Australia, although the sun coffee grown here does not harbor a large variety of canopy ant species. 相似文献
2.
Bromus tectorum (cheatgrass) is an aggressive invasive species posing threats to native ecosystems including increase in fire frequency, alteration of water and nutrient cycles and exclusion of native species. As such, it is important to monitor this species worldwide. However, outside the United States, it has been poorly studied. We studied this species at two scales: (i) at a local scale, evaluating the species presence and its determinants, along the ecotonal area between the steppe and the forest within north‐western Patagonia, to reveal whether B. tectorum is actually invading natural ecosystems in areas comparable with those invaded in USA, and (ii) at a regional scale, through a search of literature and herbaria databases on B. tectorum in South America, to determine the current known distribution of the species in this subcontinent. Results indicate that it is already invading north‐western Patagonia in Argentina, mainly in the semi‐arid part of the region, and that precipitation influences the invasion process. We found that for South America, B. tectorum has been only documented in southern Argentina and Chile. Given the similarities to other invaded regions, the possibility of invasion for Patagonia has been predicted but not prevented. It is important to study changes in the invasion level where it is already established, and to encourage managers with prevention and control strategies. Combining this information with lessons from places with extensive periods of invasion could help to initiate management of the species in areas where the invasion process is beginning and before the species spreads widely. 相似文献
3.
Ant attendance, well known behavior form towards aphid species was studied in case of the banana aphid Pentalonia nigronervosa Coquerel (Hemiptera: Aphididae) populations in four plantations in the coastal area of Carmel (Israel), where the aphid is a major pest on banana. The study characterizes the ant community the extent of attendance and the natural enemies associate with the aphid. The ants and natural enemies were sampled on mats and suckers. The ant community in the plantations was also studied by using different ant baits. In addition, the ants’ impact on the density of the banana aphid population and the potential role of local natural enemies was evaluated in artificially infested potted banana plants set in the plantation with or without a glue barrier. More than 80% of the aphid colonies on the mats were attended by ants. Ten of the twelve ant species detected in the plantations were observed attending the banana aphid. Seventeen species of potential natural enemies of the aphid, mostly belonging to the families Syrphidae, Cecidomyiidae and Coccinellidae, were found in the aphid colonies. When ant attendance on infested potted banana plants was excluded, the number of natural enemies was higher, while the aphid density was lower, than recorded on the control plants. Our finding suggest that the ants, especially the invasive species, lower the pressure of natural enemies on the aphid population and but also probably remove large quantity of honeydew which is the source of the main damage caused by the banana aphid in the local plantations. 相似文献
4.
A survey was carried out on 72 sugarcane fields in Wonji-Shoa and Methara sugarcane plantations in the Rift Valley, Ethiopia, to determine the composition and distribution of weeds and to assess the influence of soil types and crop management practises on weed species composition and distribution. A total of 180 weed taxa belonging to 40 families was recorded. Poaceae, Asteraceae, Euphorbiaceae, Fabaceae, and Malvaceae were the most abundant families based on the number of species recorded. Annuals were more common (137 taxa) than perennials (43 taxa). The most frequent and problematic weed species in the plantations, irrespective of the soil types and crop types, were Cyperus spp., Sorghum spp., Euphorbia hirta , Ipomoea cordofana , Rhynchosia malacophylla , Datura stramonium , Launaea cornuta , Portulaca oleracea , and Amaranthus spp., with a frequency of > 65%. Perennial, rhizomatous Cyperus spp. were more dominant in ratoon crops than in plant crops. A partial canonical correspondence analysis (pCCA) showed that soil types, fertilizer application, and crop cycles were the major factors influencing the species distribution in the plantations among all the variables considered in the study. The first pCCA axis structured weed species associated with light-textured soil in contrast to weeds on heavy soil. D. stramonium , Tagetes minuta , and Galinsoga parviflora were mostly associated with light-textured soil, while Xanthium strumarium , Hibiscus trionum , Vigna fischeri , and Ipomoea eriocarpa were mostly associated with heavy-textured soils. The second axis distinguished those species associated with fields receiving fertilizers versus those that were not fertilized. Rottboellia cochinchinensis and Phyllanthus tenellus were mainly associated with fertilized fields while E. hirta and L. cornuta were common on unfertilized fields. 相似文献
5.
ABSTRACTAnts are among the most diverse, abundant and ecologically significant organisms on earth. They have colonized almost all existing habitats, including urban areas, where they may pose serious problems for human activities. Here, we present different aspects of our studies on urban ants in the city of Buenos Aires aimed at collecting information on the species present in the city and at improving bait control strategies via laboratory assays. The use of these baits represents a control strategy that is environment-friendly as it avoids indiscriminate pesticide release. Moreover, we show that our baits exhibit higher efficiency when compared to a commercial bait, as it is optimized in terms of the ants’ feeding behavior even when both have the same active compound and at the same concentration. This work represents the first integrative study on urban ants in the city of Buenos Aires and indicates that the control of invasive species in urban settings may be improved by increasing the scientific knowledge of the biology of the target species. 相似文献
6.
Distribution patterns and traits of weed communities along an urban–rural gradient under rapid urbanization in Shanghai,China 
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下载免费PDF全文 In order to better understand the effects of urbanization on weed communities, the distribution of weed communities in Shanghai, China, was systematically investigated. The diversity of weed communities and four environmental factors, including the relative light intensity, soil moisture, soil compaction and soil pH, were measured in 1375 plots along an urban–rural gradient. The species diversity indices in each area along the urban–rural gradient were compared by using a one‐way ANOVA. The weed communities were identified by using clustering methods that were based on relative dominance information. A canonical correspondence analysis was used to reveal the relationships between the species composition and the environmental factors at the community level and the Spearman's rank correlation test was used to test the relationship between the number of weed communities and each environmental factor. A total of 183 species, belonging to 41 families and 123 genera, was recorded. It was found that the species richness, Shannon–Wiener diversity index and Pielou evenness index followed a unimodal curve along the urban–rural gradient. The 1375 plots were divided into 133 weed community types. All four environmental factors significantly affected the species composition of the weed communities, but only soil compaction had significant effects on the number of weed communities. It was concluded that the diversification of habitat type and environmental change along the urban–rural gradient led to more weed communities in rural areas and fewer weed communities in urban areas. Based on the species' habitats and distribution patterns, the weeds were divided into “widespread”, “urban” and “rural”. 相似文献
7.
为揭示伪步甲灾害在不同地形梯度上的差异,结合RS与GIS,于2013—2014年对新疆玛纳斯-呼图壁县草场伪步甲灾害发生情况进行了遥感监测,将危害情况分成不同类别,并分别统计2 a间伪步甲危害面积的变化情况。在此基础上,利用数字高程模型(DEM)提取高程、坡度及坡向因子,分别与不同的伪步甲危害类型进行空间叠加统计分析,探讨研究区伪步甲灾害地形梯度特征。结果表明:900~1 200 m高程范围是伪步甲灾害的高发区;伪步甲危害区主要发生在0°~8.8°区间内;坡向梯度上,严重危害区并没有表现出明显的分布规律。 相似文献
8.
The pitch canker pathogen Fusarium circinatum was first found to cause damage in nurseries and pine plantations in northern Spain in 2004. Since then, establishment of pine plantations in the region has decreased as a result of the prohibitions placed on planting Pinus spp. and Pseudotsuga menziesii in areas affected by the disease. However, although most pine species have been found to be susceptible to the pathogen under nursery conditions, little is known about how the fungus affects the trees in the field. Furthermore, it is not known whether some of the native or exotic species commonly planted in the area are also susceptible to F. circinatum. The aim of this study was to evaluate the susceptibility of several conifer species commonly planted in northern Spain to the pitch canker pathogen. For this purpose, two different trials were carried out, one under controlled laboratory conditions and the other in the field. Although most of the conifers were affected by the pathogen in the laboratory tests, only Pinus radiata, Pinus nigra, Pinus pinaster and Pinus uncinata were susceptible to the pathogen in the field. 相似文献
9.
There is a strong climate gradient in the Inner Mongolia region, China, with solar radiation and air temperature increasing but precipitation decreasing gradually from the northeast to the southwest. Sixteen Cara- gana species exist in the Inner Mongolia region. These Caragana species exhibit a distribution pattern across moisture zones and form a geographical replacement series. In order to examine the mechanisms responsible for Caragana species distribution pattern, we selected 12 Caragana species that exhibit a distinct distribution pattern across multiple moisture zones in the Inner Mongolia region, and determined the relationships between the leaf ecological and physiological traits of these Caragana species and the aridity index and solar radiation. Along with the climatic drought gradient and the solar radiation intensification from the northeast to the southwest, leaf eco- logical characteristics of Caragana species changed drastically, i.e. the leaf shape gradually turned from flat into tegular or tubbish; the leaf hair became denser, longer and lighter in color; the leaf area, leaf biomass and specific leaf area(SLA) decreased significantly; the leaf thickness and the ratio of leaf thickness to leaf area increased sig- nificantly; and the leaf chlorophyll content decreased significantly. As the climatic drought stress increased, osmotic potentials of the main osmotic adjustment substances and the cytoplasmic ion concentration of Caragana species increased significantly. Meanwhile, the total and free water contents and water potential of leaves decreased sig- nificantly; the ratio of bound to free water increased significantly; the stomatal conductance and transpiration rate reduced significantly; and the water use efficiency(WUE) increased significantly. In addition, with the intensification of climatic drought stress, peroxidase(POD) and superoxide dismutase(SOD) activities in leaves increased sig- nificantly. As a result, the malondialdehyde(MDA) content increased while the oxygen free radical content decreased. Our results showed that most of the leaf ecological and physiological traits of the 12 Caragana species varied in ac- cordance with the climatic drought gradient in the Inner Mongolia region, which reflected the adaptation of the Cara- gana species to the local climate conditions. With relatively more active metabolism and faster growth, the Caragana species in the northeast had strong competitive abilities; on the other hand, with stronger resistance to climatic drought stress, the Caragana species in the southwest could survive in harsh environments. Based on our results, we con- cluded that both the environmental gradients and the adaptive responses of Caragana species to their environments played important roles in the formation of the Caragana species distribution pattern across the Inner Mongolia region. 相似文献
10.
潜在外来入侵甜菜孢囊线虫在中国的适生性风险分析 总被引：3，自引：0，他引：3
本文应用MAXENT与GARP两种生态位模型对甜菜孢囊线虫在中国的适生性进行了风险分析和预测。结果表明甜菜孢囊线虫可在中国17个省市生存,适生范围为26°N～48°N,77.6°E～136°E。甜菜孢囊线虫入侵的高风险区:内蒙古南部、新疆西部、河北中南部、山西东北部、宁夏、甘肃北部;中风险区:北京、天津、陕西、山西大部、内蒙古西部和东南部、吉林西部、新疆北部;低风险区:河南、陕西南部、山东、内蒙古中东部、新疆中部、辽宁、吉林大部、黑龙江南部、江苏、安徽、湖北、湖南、江西、浙江北部;而青海、新疆南部、西藏、四川、重庆、云南、贵州、广西、广东、福建、海南、内蒙古少数地区和黑龙江部分地区属于基本不发生区。我国内蒙古、新疆、辽宁等省市甜菜种植区均适合甜菜孢囊线虫发生,对上述地区的进出口岸应加强甜菜孢囊线虫的检疫工作。 相似文献
11.
Management actions are essential for mitigating the potentially harmful changes in biodiversity, ecosystem function and crop/forest productivity caused by invasive species. Species distribution models, if reliable, could be used to design effective management strategies. Although several modelling methods well suited for studying invasive species have been developed for presence‐only data, often the size of available data sets for modelling is small and results are not validated with test samples. Moreover, the impact of such methods in practical applications has been overlooked. Here, we evaluated the reliability of the modelling approach based on ecological‐niche factor analysis (ENFA) implemented in Biomapper software when applied to environmental weed data in the Azores. Presence‐only data sets of two top invasive woody species (Pittosporum undulatum and Acacia melanoxylon) were used. The continuous Boyce curve was used for validation, calculated either in Biomapper (cross‐validation) or based on test samples. The species' most habitable areas that should be regarded as management targets were thus estimated from modelling and validation. By imposing size restrictions on the presence‐only data sets used in modelling and validation, other habitable areas were defined and compared. The ENFA proved to be a suitable method for modelling environmental weed distributions, regardless of the presence‐only dataset size. Moreover, the cross‐validation of Biomapper was reliable, although its results should be interpreted with caution as they could potentially lead to statistically different management target areas. 相似文献
12.
The geographical distribution of sunflower diseases in China 总被引：1，自引：0，他引：1
In various areas of China, the fourth largest sunflower-producing country in the world, 25 sunflower diseases have been reported: 19 caused by fungi, one virus disease and five caused by different species of broomrape. Their geographical distribution and economic significance are discussed. Fungi are the most prevalent disease causing agents in every region. More species of broomrape have been recorded in China than in any other country in the world. Orobanche coerulescens has not previously been reported to attack sunflower but is an important cause of disease in China. The number of diseases recorded differs among the regions, with 14 in North-east China, 11 each in North, North-west and South-west China, 10 in East China and six in Central and South China. This distribution broadly corresponds to the intensity of sunflower production. Only Puccinia helianthi and Septoria helianthi are reported in all the regions; 64% of the diseases are restricted to one or two regions. Alternaria helianthi, Septoria helianthi, Sclerotinia sclerotiorum and Orobanche coerulescens are considered to be the most important, causing 10-50% losses in yield, and even crop failure in some areas in some years. Much work remains to be done on disease control to promote the development of sunflower production in China. 相似文献
13.
This study reports the first record of Ipomoea coccinea L. [(Convolvulaceae), red morning glory] from Turkey. The literature review revealed that this taxon has not been recorded yet for the flora of Turkey. The species was mainly observed on the embankments along the Arde?en‐Çaml?hem?in road during 2016. It was again recorded during 2019 with a certain extension of the invaded area and a significant increase in population density. I. coccinea was observed in disturbed areas along roads, on the edges of tea plantations, in abandoned fields and in other waste lands. The rapid spread of the species in a short period of time suggests that it could become troublesome in future, if not managed. Therefore effective management strategies must be developed to halt its further spread. Modelling and risk assessment studies are needed to predict the potential spread and possible risks of the species to different ecosystems. 相似文献
14.
Uemeson José dos Santos Gustavo Pereira Duda Marise Conceição Marques José Romualdo de Sousa Lima Eduardo Soares de Souza 《Arid Land Research and Management》2019,33(3):255-273
Caatinga is a Brazilian dry ecosystem that occupies around 1 million km2 and is one of the largest tropical dry forests of the world. About 46% of the area that was originally covered has been deforested. Land use can cause pronounced reduction in soil carbon stocks that play a major role in the global carbon cycle. The objective of this study was to improve our understanding of the effect of land use on oxidizable carbon fractions, total carbon stocks and humic substances in different layers of soil in a Brazilian semi-arid region. We analyzed soils from tropical dry forest (TDF), forest succession with Anadenanthera falcata (ANA), with Tabebuia alba (TAB), secondary scrubby regeneration (SCR), and non-irrigated maize (MS). Forests showed larger fractions of more labile carbon, except for TDF. The most recalcitrant fraction of carbon stock, humin fraction stock, with the different land use decreased by 38–53% compared to TDF. Oxidizable carbon fractions, carbon stocks, and humic fraction stocks were able to differentiate the successional land uses and agricultural cover from TDF, mainly in the 0–5?cm layer. Our results show that changes in land use, especially with ANA forest succession, showed a larger labile carbon fraction, indicating easy decomposition and loss. Our results provide an alternative tool for the management of deforested areas in tropical dry caatinga ecosystems. This would contribute to the conservation of dry forest systems and could serve as guideline for sustainable management of agriculturally impacted caatinga areas. 相似文献
15.
ABSTRACT Infestation foci of potato cyst nematodes (Globodera rostochiensis and G. pallida) in the provinces of Zeeland, Friesland, Groningen, and Drente of the Netherlands were sampled to validate a model describing infestation foci based on data from Flevoland. Eighty-two fields were presampled to locate infestation foci using a coarse sampling grid (8 x 3 m). Parts of 37 fields containing one or more foci were sampled intensively by extracting at least 1.5 kg of soil per square meter (1.33 x 0.75 m). Forty foci were analyzed for spatial distribution characteristics of cysts using multiple regression with generalized linear models and classical linear models. The results showed that the data from all investigated cropping areas fit well to an exponential model with two parameters, the length and width gradient parameters. Significant differences in these parameter values between cropping areas could not be demonstrated. As both parameters follow a normal distribution, the probability of any combination can be described by a bivariate normal distribution. Gradient parameters were correlated, but significant correlations between these parameters and certain variables such as the nematode species involved, the time interval between sampling and the last potato crop, soil type, cropping frequency, and cyst density in the focus center could not be demonstrated. 相似文献
16.
小火蚁Wasmannia auropunctata(Roger)是原产于南美洲中南部热带地区的小型蚂蚁,因具有发达的螫针和较强的攻击性,其对人类和动物健康、生物多样性以及农业生产存在威胁。伴随人类活动,小火蚁已从其原生地入侵至其他热带与亚热带地区,被世界自然保护联盟(IUCN)列为全球最具威胁的入侵蚂蚁之一。小火蚁于2022年被报道入侵中国大陆,目前尚不清楚其入侵路径和发生程度。本文主要通过国外小火蚁的研究报道,对小火蚁的发生分布、生物生态学特性、危害特性、传播途径、监测技术以及检疫防控措施等进行简要综述,并针对我国当前小火蚁的入侵情况提出应对策略建议,以期为防控和根除小火蚁提供参考。 相似文献
17.
为有效保护北京市昆虫多样性，在调查和收集整理北京市昆虫物种分布名录的基础上，基于区级尺度研究北京市昆虫分布格局，通过回归模型和多层次方差分解等方法探讨昆虫丰富度与环境因子的关系。结果显示，北京市昆虫物种有29目409科5 259种，其中门头沟区昆虫物种数最多，为18目243科2 232种，东城区昆虫物种数最少，为8目34科68种，表现为山区昆虫多样性明显高于平原区和城区。影响昆虫科丰富度的主要因素为最高月降水量、森林覆盖率和昼夜温差月平均值；影响昆虫种丰富度的主要因素为路网密度、最高月降水量、昼夜温差月平均值和年平均气温。不论是在昆虫科或种阶元上，最高月降水量和昼夜温差月平均值对昆虫丰富度的解释能力最显著，说明降水和温度因子对昆虫分布有强限制性。表明昆虫丰富度及其分布格局是由不同环境因子共同作用的结果，降水和温度的变化对北京市昆虫丰富度有决定性的影响。 相似文献
18.
D. A. Komolafe 《国际虫害防治杂志》2013,59(2):250-251
Abstract A preliminary survey of weeds of cocoa, kola, coffee and cashew was made to identify problem weeds in order to understand their distribution and later formulate appropriate methods for their control. The survey was conducted in experimental plots, plantations and small farms. Whereas certain weeds are common to all the four tree crops, some appear to be associated with a particular crop. Many of the weeds are annuals which complete two or more life cycles a year and have a tremendous capacity for seed production. Others are short-lived perennials and perennials which are very difficult to control or eradicate. Rapid and vigorous growth of early-season weeds starts annually with rains in February or March and their mode of regeneration varies in the different species. Tree crops planted under clear-felled conditions are subjected to serious weed competition and frequent weeding is necessary to ensure the successful establishment of young seedlings. 相似文献
19.
Diplodia pinea (causing diplodia blight), Fusarium circinatum (causing pitch canker), and Mycosphaerella spp. (causing needle blight) are examples of major fungal agents that damage Pinus spp. These diseases have a major negative impact on commercial plantation production, in addition to the risk of being introduced to native forest ecosystems. This study aimed to model the spatial risk of major forest diseases to Monterey pine plantations in northern Spain, to provide a basis for more focused management strategies. Generalized linear mixed‐effects models were used to identify empirical relationships between environmental variables and disease occurrence. Field surveys and laboratory tests confirmed that D. pinea caused shoot blight in 24% of sampled plantations. Fusarium circinatum and Mycosphaerella spp. were detected in 15 and 71% of analysed plantations, respectively. The results confirmed that disease risk was strongly related to summer precipitation, moderately related to solar radiation, followed by summer temperature and tree age. The predicted probability of disease incidence was >20, 98 and 85% for Mycosphaerella spp., F. circinatum and D. pinea, respectively. The resultant maps from this study may be used to identify high‐risk areas for increased monitoring and awareness of fungal diseases. 相似文献
20.
K. Černý V. Pešková F. Soukup L. Havrdová V. Strnadová D. Zahradník M. Hrabětová 《Plant pathology》2016,65(8):1267-1278
Due to its high tolerance to acid rain, the North American Colorado blue spruce (Picea pungens) has been among the most frequent substitute tree species used in reforestation programmes in spruce mountain forests in the Ore and Sudeten Mountains in the Czech Republic after destruction by sulphur dioxide pollution in the second half of the last century. This species was planted on more than 8800 ha of destroyed mountain forest stands in the Ore Mountains alone. New plantations prospered until a massive outbreak of the gemmamyces bud blight, first identified in 2009. The causal agent, Gemmamyces piceae, induced massive bud blight in infected trees – bud loss progressively increased to 70–80% or more, and because the trees were not able to replace the natural loss of older needles, they quickly withered and died. Many plantations disrupted by the pathogen had to be cut down. Although several resistant genotypes have been identified, the cultivation of this species in forest stands has no future in this area. Because this disease was also identified in several ornamental plantations in the area, the bud blight epidemic haunts public green space administrators and nursery and Christmas tree plantation owners. Other pathogens and pests, such as Lophodermium piceae, Sirococcus conigenus and Elatobium abietinum, have also been identified as involved in the damage to P. pungens. 相似文献