麻楝蛀斑螟生物学及其防治研究   总被引：3，自引：0，他引：3  

陈英林  查广林 《北京林业大学学报》1998,20(4):59-64

麻楝蛀斑螟在云南石岩寨地区１年发生４代,以蛹越冬．该虫以幼虫钻蛀珍贵速生树种红椿树主梢和侧梢,造成枝条中空、断折,从而形成多头树而难以成材．云南省红椿主产区的林分,６０％～１００％的植株受其危害,且幼林受害尤重．生产实践证明,螟害是造成省内红椿造林多年未获成功的主要因素．该文就麻楝蛀斑螟的分布、危害、生物学特性、发生规律和有效防治方法进行了较深入的探讨。  相似文献   

云南松叶蜂的分布型适应对策及生活史研究   总被引：3，自引：0，他引：3  

徐正会 《西南林学院学报》1998,18(4):275-281

松叶蜂是云南省的重要食叶性害虫,目前为止在云南省已记载松叶蜂科昆虫６属１６种,按照分布特点可将云南省的１６种松叶蜂划分为３个分布型：广布型,窄布型,点布型,其中３个点布型种：油杉小松叶蜂,景洪吉松叶蜂,楚雄新松叶蜂是稀有物种,建议将它们列入保护名单。根据松叶蜂地食物,气候,天敌等生态因素的适应特点,可将１６种松叶蜂分为２个适应型：群居生活型和散居生活型,前者有时在森林中大量繁殖,并暴发成灾,而后者  相似文献   

油菜新害虫——油菜叶露尾甲研究   总被引：3，自引：0，他引：3  

贺春贵  王国利  范玉虎  邹亚暄  邓怀义 《西北农业学报》1998,7(4):18-23

油菜叶露尾甲Ｓｔｒｏｎｇｙｌｌｏｄｅｓｖａｒｉｅｇａｔｕｓ（Ｆａｉｒｍａｉｒｅ,１８９１）是油菜上发现的新害虫。１９９４－１９９７年的调查研究表明：该虫在甘肃省主要分布大于厦河和洮河流域,危害春油菜,以中、晚人油菜受害最重。  相似文献   

Landraces: A review of definitions and classifications   总被引：2，自引：0，他引：2  

A.C. Zeven 《Euphytica》1998,104(2):127-139

The first reference to landraces as genetic resources dates from 1890. Some 20 years later the first definitions of a landrace were published. In the period 1909–1952 several definitions of the term landrace have been presented. No definitions were discovered in articles published in the period 1953–1974. The reason could be that after the Second World War attention of plant breeders and others was focussed on making instant progress. New definitions have been presented since 1974. Genetically related landraces form a landrace group. Synonyms of the term landrace and landrace group as cited in the literature are also given. The classification of types of landraces given by Mayr in 1934 had been discussed and an amended classification provided, paying attention to contamination caused by seed change. As a landrace has a complex and indefinable nature an all-embracing definition cannot be given. However, I suggest the following: an autochthonous landrace is a variety with a high capacity to tolerate biotic and abiotic stress, resulting in a high yield stability and an intermediate yield level under a low input agricultural system. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Seasonal spawning and wind‐regulated retention‐dispersal of early life stage Atlantic cod (Gadus morhua) in a Newfoundland fjord     

D. CRAIG KNICKLE  GEORGE A. ROSE 《Fisheries Oceanography》2010,19(5):397-411

Sequential ichthyoplankton surveys were used to determine the spatial and temporal distribution of eggs and larvae over coastal spawning grounds of Atlantic cod (Gadus morhua) in Smith Sound, Trinity Bay, Newfoundland, during the spring and summer of 2006 and 2007. Egg densities showed similar patterns for both years with two peaks in abundance in spring (March–April) and late summer (late July). A clear progression of development stages (1–4) was observed in spring and summer in 2006 and summer in 2007, suggesting retention of eggs within the Sound during these periods. Modelled predictions of vertical egg distributions indicated eggs were broadly distributed near the surface during spring (March–April), but were concentrated below the pycnocline (>10 m) within the inner portions of the Sound during the summer months (July–August). Back‐calculated peaks in spawning based on water temperatures were estimated at 11 and 4 April for 2006 and 2007, respectfully, with late season peaks centred on 21–24 July for both years. Environmental data indicated cooler water temperatures and periods of high wind stress in spring, and warmer, calmer periods late summer, consistent with higher retention and faster development times on the spawning grounds later in the season. We conclude that spring and summer spawning events result in different distributions of early life stages and may lead to different distributions of juvenile and adult fish.  相似文献   

A transient coastal wetland: from estuarine to supratidal conditions in less than 2000 years—Boca do Rio,Algarve, Portugal     

H. D. Allen 《Land Degradation \u0026amp; Development》2003,14(3):265-283

Palaeoecological analysis of a 3 m sediment core from a coastal site in the western Algarve, near Lagos, Portugal, reveals the changing ecological characteristics of the wetland environment during the late Holocene. The dinoflagellate record and sedimentary characteristics show that approximately 2000 years ago the modern Boca do Rio wetlands were an estuary. By about 1200 ¹⁴C years BP, transition to a lower energy environment was taking place. The pollen record at this time indicates the existence of typical salt marsh vegetation. There is a likely hiatus in the sedimentary record caused by the tsunami associated with the Lisbon earthquake of ad 1755. A barrier lake, impounded by tsunami deposits, existed for approximately 60 years before being breached, followed by a reoccurrence of saline conditions. A comparison of the mineral magnetic signature of the sediments with that of soil samples from the catchment suggests a relatively local provenance for some of the sediments, rather than the highly erodible Carboniferous rocks of the Algarve's Serra uplands. However, it is also suggested that there is a biogenic component to the magnetic mineralogy. Coastal wetlands are among the most vulnerable Mediterranean environments. The history and future of the Boca do Rio wetlands is examined in the context of alluviation history, rising sea levels, both past and future, and catchment land use. Changing patterns of cultivation, irrigation and land abandonment during the last 50 years are likely to have increased water demands within the catchment and therefore decreased river discharge to the wetlands. Consequently, the continued existence of the wetlands in their present form is in doubt, despite being part of a protected natural park. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Does pattern matter? Exploring the pathways and effects of urban green space on promoting life satisfaction through reducing air pollution     

《Urban Forestry & Urban Greening》2023

Urban green space is widely acknowledged to promote public health through multiple pathways. However, there is limited understanding of how the spatial patterns of green space might play different roles in such a process. This study examined potential pathways through which spatial patterns of green space improved people’s life satisfaction (LS) by reducing air pollution. A partial least squares structural equation model was adopted to explore these pathways in sampled urban areas (township) of China (n = 60). Green space spatial patterns were measured using landscape metrics of size, aggregation, fragmentation, and diversity. The results did not show that green space spatial pattern promoted LS by reducing air pollution. However, green space size and fragmentation were negatively associated with air pollution (mainly PM 2.5, PM 10, and NO 2). The pattern of highly densely distributed small green spaces was related to higher LS, as was high diversity of green space type. Simply adopting a fragmented green space pattern to reduce air pollution might be simultaneously associated with reduced LS. This alerts decision-makers and planners to the potential “double-edged sword” effect of optimizing green space structures to improve air quality, which may not yield strongly favorable results due to the impacts that hinder LS.  相似文献   

Reproduction and recruitment of the brown shrimp Crangon crangon in the inner German Bight (North Sea): An interannual study and critical reappraisal     

Kim Hünerlage  Volker Siegel  Reinhard Saborowski 《Fisheries Oceanography》2019,28(6):708-722

The brown shrimp, Crangon crangon, is the most important target of the coastal crustacean fisheries in the German Bight. In order to evaluate the relation between the abundance of ovigerous females and larvae in spring and the recruitment success in autumn, we first analysed the seasonal appearance of ovigerous females and larvae from weekly samples throughout 2012. The spawning season in the German Bight extends over several months comprising multiple unsynchronized spawning events. The minimum shares of ovigerous females appeared in early autumn, and the highest shares in late winter bearing mostly early egg stages. We defined the putative start of the reproductive cycle for November when the frequency of ovigerous females started to increase. There was no distinct separation between winter and summer eggs, but a continuous transition between large eggs spawned in winter (the early spawning season) and batches of smaller eggs in spring and summer. Larval densities peaked in April/May. Consequently, regular annual larval surveys from 2013 to 2016 were scheduled for April/May and extended to six transects covering the inner German Bight. Ovigerous females were most abundant in shallow waters above the 20‐m isobaths, which also explained regional differences in abundance between the regions off North Frisia and East Frisia. No relation was obvious between the number of larvae in spring and recruited stock in autumn. Due to the short lifespan of C. crangon, the combination of various abiotic factors and predator presence seems to be the principal parameters controlling stock size.  相似文献   

Biological and ecological aspects of the deep‐water red crab populations inhabiting isolated seamounts to the west of the Azores (Mid‐Atlantic Ridge)     

Rgis Santos  Mrio Pinho  Octvio Melo  Joo Gonalves  Ana Leocdio  Ana Aranha  Gui Menezes  Eduardo Isidro 《Fisheries Oceanography》2019,28(6):723-734

Seamounts are common topographic features in the Mid‐Atlantic Ridge (MAR) including the Azores. However, the knowledge on the ecology of seamounts in this region remains scarce despite needs for assessment and management of seamount resources such as the developing fisheries for deep‐water crabs. We described here for the first time the biological characteristics of an unexploited virgin deep‐water red crab Chaceon affinis population on seamount areas of the MAR to test the hypothesis that its general life history characteristics are similar in different ecosystem types (coastal areas and seamounts) across Macaronesia. We used a randomly stratified design to prospect a layer between 600 and 900 m depth around the summit of two isolated seamounts off the Azores. Results were consistent with the literature information in relation to the patterns of depth distribution, size and sex structure, and reproductive aspects. On the other hand, seamounts showed higher abundances when compared to previously studied coastal areas. Abundance may be also different between seamount areas as a function of the suitable bottom type available and presence of hydrothermal vents. We recommend that the essential habitat of the species should be better mapped identifying vulnerable areas before the development of any fishery.  相似文献   

The role of sand lances (Ammodytes sp.) in the Northwest Atlantic Ecosystem: A synthesis of current knowledge with implications for conservation and management     

Michelle D. Staudinger  Holly Goyert  Justin J. Suca  Kaycee Coleman  Linda Welch  Joel K. Llopiz  David Wiley  Irit Altman  Andew Applegate  Peter Auster  Hannes Baumann  Julia Beaty  Deirdre Boelke  Les Kaufman  Pam Loring  Jerry Moxley  Suzanne Paton  Kevin Powers  David Richardson  Jooke Robbins  Jeffrey Runge  Brian Smith  Caleb Spiegel  Halley Steinmetz 《Fish and Fisheries》2020,21(3):522-556

The American sand lance (Ammodytes americanus, Ammodytidae) and the Northern sand lance (A. dubius, Ammodytidae) are small forage fishes that play an important functional role in the Northwest Atlantic Ocean (NWA). The NWA is a highly dynamic ecosystem currently facing increased risks from climate change, fishing and energy development. We need a better understanding of the biology, population dynamics and ecosystem role of Ammodytes to inform relevant management, climate adaptation and conservation efforts. To meet this need, we synthesized available data on the (a) life history, behaviour and distribution; (b) trophic ecology; (c) threats and vulnerabilities; and (d) ecosystem services role of Ammodytes in the NWA. Overall, 72 regional predators including 45 species of fishes, two squids, 16 seabirds and nine marine mammals were found to consume Ammodytes. Priority research needs identified during this effort include basic information on the patterns and drivers in abundance and distribution of Ammodytes, improved assessments of reproductive biology schedules and investigations of regional sensitivity and resilience to climate change, fishing and habitat disturbance. Food web studies are also needed to evaluate trophic linkages and to assess the consequences of inconsistent zooplankton prey and predator fields on energy flow within the NWA ecosystem. Synthesis results represent the first comprehensive assessment of Ammodytes in the NWA and are intended to inform new research and support regional ecosystem‐based management approaches.  相似文献