三七表型变异及其对气候因子的响应

为了解三七(Panax notoginseng)表型变异的发生机理,结合地理信息系统和多元统计分析,研究了云南和广西的3年生栽培三七表型变异与气候因子的关系及性状间的内在联系。结果表明,三七的茎生物量、地下生物量和总生物量变异系数较大;地上生物量比和地下生物量比的变异系数较小。相关分析表明,表型变异受多种气候因子的共同影响,降水对三七表型变异的影响强于温度,不同季节降水量变化幅度是决定三七茎粗和叶面积的关键气候因子。三七地下生物量、总生物量随年均气温、年均降水量、最干月降水量的升高呈下降趋势,而随月均温变幅、昼夜温差与年温差比值的升高呈增加趋势。日照时数的增加使三七地上生物量比降低,并促进地下生物量和总生物量的积累。因此,随产地气候条件的变化,三七表现出较强的形态性状变异,可能是三七通过表型变异以适应异质生境。     

Bioclimatic analysis of the distribution of damage to native plants in Tasmania by Phytophthora cinnamomi

Climatic profiles were generated by the computer program BIOCLIM for three sets of sites in native vegetation in Tasmania: (i) 308 sites at which Phytophthora cinnamomi was isolated from diseased plants Pc+ ive; (ii) 322 sites in healthy plant communities from which P. cinnamomi could not be recovered Pc?ive; and (iii) 801 sites representing the climatic range across Tasmania. A discriminatory analysis comparing the first and third sets indicated that seven of the 16 climatic indices available for analysis were good discriminators of the distribution of damage by P. cinnamomi. The analysis suggests that damage to native vegetation due to P. cinnamomi is unlikely on sites where annual mean temperature does not exceed 7.5°C or annual mean rainfall is < 600 mm. Two maps were produced to indicate those areas of Tasmania that have climates suited to damaging interaction between P. cinnamomi and native vegetation. The first was based on those sites that had annual mean temperature more than 7.5°C and annual mean rainfall less than 600 mm. The second included those sites that matched the values of the Pc+ ive set for all seven good discriminators. The two approaches produced similar results. Areas in which even the most favourable microsites are unlikely to support pathogenic activity by P. cinnamomi constitute less than 20% of the land area. Twelve substantial areas of native vegetation that occur in climates suited to infection by P. cinnamomi. but for which no record of the fungus exists, have been identified.     

Variation in litterfall-climate relationships between coniferous and broadleaf forests in Eurasia

Aim The objectives of this study were to determine the relationships between climatic factors and litterfall in coniferous and broadleaf forests in Eurasia and to explore the difference in litterfall between coniferous and broadleaf forests as related to climate at a continental scale. Location We have used data from across Eurasia. Methods The relationships between litterfall and climatic factors were examined using linear regression analysis of a compilation of published data from coniferous and broadleaf forests in Eurasia. Results The relationships between litterfall and climatic factors show that in the temperate, subtropical, and tropical areas, broadleaf forests had higher litterfall than coniferous ones, whilst the opposite was found for boreal forests. Combining all climatic zones, a multiple regression analysis using annual mean temperature (T) and annual precipitation (P) as independent variables gave an adjusted R² () of 0.272 for total litterfall in coniferous forests (n = 199, P < 0.001), 0.498 for broadleaf litterfall (n = 240, P < 0.001), and 0.535 for combined coniferous and broadleaf litterfall (n = 439, P < 0.001). The linear models for broadleaf stands have significantly higher coefficients for T and P than those for coniferous ones but the intercepts were similar. Thus, litterfall in broadleaf forests increased faster with T and P than that in coniferous forests. Further, a transformation of temperature and precipitation to relative units showed that a relative‐unit change in T had a larger impact than P on total litterfall in broadleaf forests. The results indicate that at a continental scale, climatic controls over litterfall differ between coniferous and broadleaf forests. Conclusions A relative unit change in annual mean temperature has a greater effect on litterfall compared to the same change in annual precipitation across the Eurasian forests. Further, the higher response to T for broadleaf forests indicates a difference in climate control between coniferous and broadleaf forests at a continental scale, and consequently different litterfall responses to climate change.     

辽宁省人工林樟子松径向生长对水热梯度变化的响应

基于树轮年代学的理论和方法,建立辽宁地区人工林樟子松年轮宽度年表网络,研究人工林樟子松树木年轮生长变化,探讨樟子松生长与气候变化的关系以及其对水热梯度变化的响应规律。结果表明,研究区各采样点人工林樟子松的径向生长变化呈现较为一致的显著下降趋势(P0.05),并且下降趋势由西北至东南降低。空间上水平上,研究区樟子松的径向生长与研究区降水和相对湿度的空间梯度变化吻合(P0.05),均呈西北至东南增加的特点;各采样点樟子松年轮宽度变化的平均敏感度与降水量、相对湿度显著负相关关系(P0.05),但与温度的正相关关系不显著。各样点樟子松径向生长与月降雨量和月平均相对湿度多呈正相关关系,与月平均温度多呈负相关关系,进一步表明区域水分因子对人工林樟子松生长的限制作用明显。     

唐古特白刺叶功能性状沿气候梯度的变异特征

叶功能性状与植物的生长对策及资源利用效率密切相关,研究叶功能性状沿气候梯度的变异特征能为理解植物对气候变化的响应机制提供一种简便可行的测定指标。以我国西北荒漠地区广泛分布的唐古特白刺（Nitraria tangutorum）为研究对象,对其比叶面积（SLA）、单位质量和单位面积叶氮含量（N_mass、N_area）、单位质量和单位面积叶建成成本（CC_mass、CC_area）进行测定,分析这些叶功能性状及性状相关关系沿气候梯度的变异特征。结果表明,唐古特白刺叶功能性状（CC_area除外）在气候梯度下存在显著差异,其中,温度是决定唐古特白刺SLA变化的主要因子,SLA随着温度的增加而增加;降水和温度对唐古特白刺N_mass、N_area和CC_mass均有显著影响,N_mass和N_area随着降水和温度的增加而降低,而CC_mass呈增加趋势。沿气候梯度,唐古特白刺SLA-N_mass、CC_mass-N_mass和CC_area-N_area的线性正相关关系发生平移,导致在相同SLA、CC_mass和CC_area下,降水和温度较低的地区具有更高的N_mass和N_area。这一结果表明唐古特白刺能通过调节叶功能性状之间的关系来适应气候的变化,并形成性状间的最佳功能组合。     

芦芽山阳坡不同海拔华北落叶松径向生长对气候变化的响应

为研究树木生长对气候变化的响应状况,选取芦芽山阳坡的3个海拔高度建立了华北落叶松(Larix principis-rupprechtii)的树轮宽度年表。年表的统计参数表明,3条年表均为研究气候信息的可靠资料。结果表明,芦芽山阳坡华北落叶松的径向生长和生长与气候的关系均具有海拔差异,中海拔(2440 m)和高海拔(2540 m)的华北落叶松具有相似年际生长变化,而二者均与低海拔(2330 m)华北落叶松的年际生长不同。低海拔华北落叶松的生长与4月平均气温和上一年11月降水量显著负相关,而中海拔和高海拔的生长均与上一年10月平均气温和6月降水量显著负相关。通过年表与气候因子之间的滑动相关分析发现,3个海拔高度华北落叶松生长与气候因子的关系均不稳定,生长与气温条件之间的显著相关关系是随着气温升高而出现的。气温的升高引起了华北落叶松生长与气温因子关系的海拔差异,以及径向生长的海拔差异。这一结果对于气候变化对植被垂直梯度影响的研究具有一定参考价值。     

Estimating the Productivity of the Black Sea Bivalve Chamelea gallinafrom the Size and Biomass of Its Populations

Characteristics of annual production based on various mass data (whole animal mass; shell mass; and wet, dry, and ash-free dry soft tissue mass), the P/B coefficient, and specific production were estimated for the bivalve mollusk Chamelea gallinasampled from 21 localities in the northwestern and eastern Black Sea. The annual production correlated with population biomass (r= 0.994) and mean individual mass (r= –0.737), while the P/Bcoefficient depended mainly on mean individual mass (r= –0.719). Estimates of the P/Bcoefficient in Ch. gallinafrom the Black Sea were smaller than those of other marine invertebrates found worldwide with the same energy equivalent. Multiple linear regression equations were calculated for empirical relationships of various characteristics of annual production to the population biomass and mean individual biomass of Ch. gallina.     

广西金钟山细叶云南松径向生长及其对气候因子的响应

为探究广西金钟山细叶云南松径向生长及其对气候的响应,该文建立了细叶云南松树木年轮标准年表,采用响应分析探讨了径向生长与气候因子的关系,并使用逐步回归和方差分解量化了不同气候因子对径向生长的影响。结果表明:(1)响应分析结果显示,上一年1月、8月、9月、11月的日照时数以及上一年10月的平均最低气温和平均气温与标准年表年轮宽度均呈显著正相关,而上一年6月降雨量>10 mm的天数与年轮宽度呈显著负相关; 当年2月的降雨量、3月的空气相对湿度和平均最低气温、6月的日照时数以及9月的平均气温和平均最高气温均与年轮宽度呈显著正相关。(2)逐步回归最终模型的方差分解结果显示,上一年10月的平均最低气温对细叶云南松径向生长的影响最大(方差解释量达23.35%),其次是当年9月的平均最高气温(方差解释量为10.39%); 上一年1月和11月的日照时数分别解释了径向生长变异的3.94%和6.58%。综上表明,秋季的温度和冬季的光照条件是限制细叶云南松径向生长最主要的气候因子,早春干旱和雨季大降雨量会降低细叶云南松的径向生长。     

Genome size and environmental factors in the genus Pinus

Nuclear 1C DNA content in haploid megagametophyte tissue of 18 North American and one exotic Pinus species was determined using scanning microspectrophotometry. The nuclear DNA content in root meristematic cells of Zea mays L. ssp. mays, inbred line Va35 (4C = 10.31 pg) was used as a standard. DNA content measured by microspectrophotometry was verified using laser flow cytometry with two additional standards, Hordeum vulgare cv. Sultan (2C = 11.12 pg) and P. eldarica (2C = 47.30 pg). DNA values obtained by both methods were significantly correlated (r = 0.987). The 1C nuclear DNA content ranged from 21 pg to 31 pg. The ratio of DNA content in embryo tissue of P. eldarica to that in megagametophyte tissue was 1.72 by scanning microspectrophotometry and 1.74 by laser flow cytometry. To date, this is the most comprehensive data set available for North American Pinus species. Relationships between genome size of 18 North American Pinus species and climatic factors and indices of growth were investigated using regression and correlation analyses. Positive correlations were observed between nuclear DNA content and growth indices, minimum seed-bearing age, and seed dimensions. Strong negative correlations were observed between nuclear DNA content and two climatic factors, the lowest mean annual and monthly precipitation (excluding January) and the highest mean monthly spring air temperature. These correlations suggest that the large genome size and its variation in Pinus are adapted responses to the habitats of these species.     

Evaluation of a Quantitative Magnetic Resonance Method for Mouse Whole Body Composition Analysis

Objective: To evaluate applicability, precision, and accuracy of a new quantitative magnetic resonance (QMR) analysis for whole body composition of conscious live mice. Research Methods and Procedures: Repeated measures of body composition were made by QMR, DXA, and classic chemical analysis of carcass using live and dead mice with different body compositions. Caloric lean and dense diets were used to produce changes in body composition. In addition, different strains of mice representing widely diverse populations were analyzed. Results: Precision was found to be better for QMR than for DXA. The coefficient of variation for fat ranged from 0.34% to 0.71% compared with 3.06% to 12.60% for DXA. Changes in body composition in response to dietary manipulation were easily detected using QMR. An increase in fat mass of 0.6 gram after 1 week (p < 0.01) was demonstrated in the absence of hyperphagia or a change in mean body weight. Discussion: QMR and DXA detected similar fat content, but the improved precision afforded by QMR compared with DXA and chemical analysis allowed detection of a significant difference in body fat after 7 days of consuming a diet rich in fat even though average body weight did not significantly change. QMR provides a very precise, accurate, fast, and easy‐to‐use method for determining fat and lean tissue of mice without the need for anesthesia. Its ability to detect differences with great precision should be of value when characterizing phenotype and studying regulation of body composition brought about by pharmacological and dietary interventions in energy homeostasis.     

Climatic signals in tree rings of <Emphasis Type="Italic">Burkea africana</Emphasis> and <Emphasis Type="Italic">Pterocarpus angolensis</Emphasis> from semiarid forests in Namibia

Tree-ring studies contribute worldwide to the understanding of climate and its relation to tree growth. Long tree-ring chronologies serve as climate proxies for the reconstruction of past, pre-instrument climate and its recent change. In tropical regions, the availability of exactly dated tree-ring chronologies is limited. The dendroclimatic potential of two dominant species from dry forests in northern Namibia was examined in the study presented in this paper. Both species (Burkea africana Hook and Pterocarpus angolensis DC) were sampled at two sites (ca. 900 km apart), and the response to several climatic variables, including ENSO indices, is studied. All specimens showed distinct growth rings and cross-dating between radii was successful for all trees. Species-specific mean curves were built for both sites. The mean curves of different species of the same site synchronised significantly, allowing the construction of a site-specific chronology. Synchronisation between sites was not possible, but spectral analysis of the chronologies implied that both show similar long-term (6.7 year) oscillation patterns. B. africana is more sensitive to rainfall variation than P. angolensis at both sites. Growth response to rainfall was positive, but a time-lag in the reaction occurred between the sites, corresponding to the time-lag of the beginning of the rainy season. Air temperature showed a negative correlation with stem increment at both sites. The response at the westernmost site to two ENSO indices indicates a tree growth decrease during El Niño years, which are generally dry in southern Africa.     

Evaluation of a Quantitative Magnetic Resonance Imaging System for Whole Body Composition Analysis in Rodents

We evaluated the EchoMRI‐900 combination rat and mouse quantitative magnetic resonance (QMR) body composition method in comparison to traditional whole‐body chemical carcass composition analysis (CCA) for measurements of fat and fat‐free mass in rodents. Live and postmortem (PM) QMR fat and lean mass measurements were obtained for lean, obese and outbred strains of rats and mice, and compared with measurements obtained using CCA. A second group of rats was measured before and after 18 h food or water deprivation. Significant positive correlations between QMR and CCA fat and lean mass measurements were shown for rats and mice. Although all live QMR fat and lean measurements were more precise than CCA for rats, values obtained for mice significantly differed from CCA for lean mass only. QMR performed PM slightly overestimated fat and lean values relative to live QMR but did not show lower precision than live QMR. Food deprivation reduced values for both fat and lean mass; water deprivation reduced estimates of lean mass only. In summary, all measurements using this QMR system were comparable to those obtained by CCA, but with higher overall precision, similar to previous reports for the murine QMR system. However, PM QMR measurements slightly overestimated live QMR values, and lean and fat mass measurements in this QMR system are influenced by hydration status and animal size, respectively. Despite these caveats, we conclude that the EchoMRI QMR system offers a fast in vivo method of body composition analysis, well correlated to but with greater overall precision than CCA.     

Litter production,nutrient recycling and litter accumulation inPinus caribaea Morelet var.hondurensis stands in the northern Guniea savanna of Nigeria

Summary The seasonal pattern and quantity of litterfall were studied during a two-year period in two unthinned stands ofPinus caribaea Morelet var. hondurensis Barr. and Golf. in Nigeria. Although pine needles were cast continuously throughout the year, the peak period of litterfall occurred in the dry months of March and April. Mean values of annual litterfall were 3068 and 3665 kg/ha in the two stands aged 7–9 and 9–11 years respectively. Nutrient returns in litterfall in the stands had mean values of 15.0, 0.6, 17.3, 18.2 and 6.3 kg/ha of N, P, K, Ca and Mg respectively. Comparatively low amounts of N and P returned in litterfall were attributed to soil deficiencies of the two elements.Measurements of ground litter showed considerable dry matter accumulation (11378 kg/ha) in the litter layers. Estimates of litter decomposition rate and recycling time showed that it would take 3 to 4 years for the organic matter in annual litterfall to decompose completely as contrasted to about 2 to 5 months often reported under mixed nautral savanna vegetation in the same climatic environment. Similar estimates of nutrient recycling time also showed that between 2 to 4 years were required to mineralize nutrient elements in the annual litterfall; the relative mobilities of the elements were in the order K>Mg>P>NCa.     

青藏高原两种植被类型净初级生产力与气候因素的关系及周转值分析

基于2008—2016年青海海北站9年净初级生产力及气候因子监测数据,分析了青藏高原高寒小嵩草草甸和高寒金露梅灌丛两种植被净初级生产力年际动态,并探讨了气候因子对其影响及其不同土层深度根系周转值特征。结果表明:(1)年际尺度上,小嵩草草甸地上净初级生产力表现为显著增加趋势,增幅为7.02 g m~(-2) a~(-1),而金露梅灌丛地上净初级生产力相对较为稳定;对于其地下净初级生产力和总生产力,小嵩草草甸和金露梅灌丛均表现为增加趋势(P0.05),9年间小嵩草草甸地上、地下和总净初级生产力平均值分别为(217.55±9.95)、(1882.75±161.33) g m~(-2) a~(-1)和(2100.30±163.38) g m~(-2) a~(-1),金露梅灌丛地上、地下和总净初级生产力9年间平均值分别为(256.27±11.4)、(1614.31±173.03) g m~(-2) a~(-1)和(1870.58±177.93) g m~(-2) a~(-1)。(2)不同植被类型地上净初级生产力对气候因素响应不同,金露梅灌丛地上净初级生产力主要受温度影响,而温度对小嵩草草甸地上净初级生产力无显著影响。此外,降水不是限制高寒生态系统草地地上净初级生产力主要因子,相比于降水影响,高寒生态系统地上净初级生产力更受温度调控。(3)年均温和年降水对金露梅灌丛和小嵩草草甸地下净初级生产力均无显著影响(P0.05),表明高寒生态系统,其地下生产力受外界气候条件变化影响微弱,是一个稳定的碳库。(4)两种植被类型其根系周转值均随着土壤深度的增加呈逐渐增加趋势,且高寒灌丛根系周转值明显高于高寒草甸根系周转值。研究表明,在全球气候变暖背景下将会增加金露梅灌丛地上净初级生产力,而对小嵩草草甸地上净初级生产力无显著影响。     

Rain,prey and predators: climatically driven shifts in frog abundance modify reproductive allometry in a tropical snake

To predict the impacts of climate change on animal populations, we need long-term data sets on the effects of annual climatic variation on the demographic traits (growth, survival, reproductive output) that determine population viability. One frequent complication is that fecundity also depends upon maternal body size, a trait that often spans a wide range within a single population. During an eight-year field study, we measured annual variation in weather conditions, frog abundance and snake reproduction on a floodplain in the Australian wet-dry tropics. Frog numbers varied considerably from year to year, and were highest in years with hotter wetter conditions during the monsoonal season (“wet season”). Mean maternal body sizes, egg sizes and post-partum maternal body conditions of frog-eating snakes (keelback, Tropidonophis mairii, Colubridae) showed no significant annual variation over this period, but mean clutch sizes were higher in years with higher prey abundance. Larger females were more sensitive to frog abundance in this respect than were smaller conspecifics, so that the rate at which fecundity increased with body size varied among years, and was highest when prey availability was greatest. Thus, the link between female body size and reproductive output varied among years, with climatic factors modifying the relative reproductive rates of larger (older) versus smaller (younger) animals within the keelback population.     

气候变化背景下青藏高原东部猪毛蒿物候的变化规律和影响因素

近几十年来青藏高原正经历着广泛而深远的气候变化,这种变化对当地物种的物候及分布格局产生了显著影响。猪毛蒿作为干旱半干旱地区的优势物种和影响群落稳定性的关键物种,青藏高原东缘是其重要的分布区域之一,然而其物候将如何应对气候变化目前我们尚不清楚。为此,基于青海省东部连续20年的气象数据和原位物候观测实验,探讨猪毛蒿物候的变化规律及量化不同气候因子的相对贡献率。结果表明：1)过去20年间年均温和年均每日日照时长分别呈现出显著的上升和下降趋势,而年降水和年均每日最大风速没有显著的变化;2)20年间猪毛蒿返青-开花的时间间隔和开花-结果的时间间隔并未表现出显著的变化趋势,结果-枯黄的时间间隔显著缩短;3)所有气候因子均对猪毛蒿不同物候的时间间隔有显著影响,其中最大风速是影响猪毛蒿物候时间间隔最重要的气候因子。这一研究发现可以为气候变化情景下青藏高原高寒植物的保护和利用提供理论依据。     

Notes on Quercus ilex L. in Liguria (NW Italy)

The climatic characteristics of the Liguria region have been outlined by means of raw data and derived indices (water balance related to potential evapotraspiration, Rivas-Martinez's index of mediterraneity and thermicity, De Martonne's index of dryness, and Emberger's pluviothermic quotient and index of summer dryness). Their interpretation suggests that Liguria is a boundary region between two different climatic areas: the Mediterranean and that of Central Europe.The distribution of Quercus ilex communities in Liguria have suffered the heavy consequences of human activity on the coastal belt of the region. There is, however, sufficient evidence to show that their presence is closely linked to climatic conditions. Quercus ilex communities are absent from the western coastal belt where the annual water balance is below –50 mm and high mean temperatures occur. They are also absent from marly limestone dominated areas where annual water balance is below 300 mm. Quercus ilex woods show a preference for water balance values between 0 and 600, with the better developed forests being found in central and eastern coastal Liguria.The Ligurian Quercus ilex woods are ascribed to Quercetum ilicis Br.-Bl. 1915. Given that the presence within their floristic composition of a group of species of Querco-Fagetea (more species in eastern stands, few in western ones) is an almost constant characteristic, the subass. fraxino-ostryetosum Mariotti 1984 can be retained for many of them. Quercus ilex is not present in the initial succession stages of Mediterranean Liguria vegetation. It can be found in later stages when the vegetation is more fully developed towards a maquis type structure. In this case it tends to become dominant and the community develops (if no fire or other human interference occurs) into a Quercus ilex forest. Frequently, this succession takes place under an old tree layer cover (generally Pinus sp.), a remanant of man's past management of the vegetation in the area.     

陕西省3种主要树种叶片、凋落物和土壤N、P化学计量特征

以陕西省29个县(市)39个样点的刺槐、辽东栎和油松林为研究对象,分析比较不同树种乔木叶片、凋落物与土壤N、P化学计量特征及其与经纬度、海拔、年均温度和年降水等环境因子间关系的异同以及三者之间可能存在的关系,以期为认识陕西省主要森林树种养分限制状况、制定合理的植被管理和恢复措施提供理论依据。结果表明:3树种叶片N、P含量及比值均为刺槐辽东栎油松,与叶片相比,凋落物中N、P含量变化幅度较小,为刺槐辽东栎油松,N∶P比值为油松辽东栎刺槐。10—20 cm与0—10 cm土层相比,3树种中除辽东栎中P含量差异不显著外,其它指标N、P含量及N∶P比值均显著下降(P0.05)。刺槐、辽东栎和油松叶片N、P含量与土壤N、P含量均没有显著相关性,以刺槐、辽东栎和油松3种植物叶片为总体来说,P含量与土壤P含量显著正相关(P0.05)。叶片N、P含量均大致表现出随着年均温度和年降水的增加而增加,随着经纬度的增加而降低的趋势,这一点在刺槐叶中最为明显。凋落物N含量随着年均温度和年降水的增加而增加,随着纬度和经度的增加而降低;P含量随着年降水和经度的增加而降低;N∶P比值随着年均温度和年降水的增加而增加,随着纬度的增加而降低。研究区内,土壤N、P含量随着纬度、海拔的增加和年均温度、年降水、经度的降低而增加,N∶P比值则呈相反的趋势。3树种土壤N、P含量及N∶P比值中,P含量比N含量受环境影响更大,且0—10 cm和10—20 cm土层N、P含量及N∶P比值与各环境因子的关系基本一致。     

华北平原地区景观格局对麦田害螨种群数量的影响

农业生产的集约化经营导致农田景观格局日趋单一,而农田景观格局的变化势必对害虫种群产生深刻的影响,阐明景观因子对害虫种群的作用是通过生境管理进行害虫控制的基础。以华北平原地区的山东省为研究区域,24个县级单元为样点,通过对卫星遥感影像和土地覆盖分类数据的分析,获取了样点单元的景观格局指数,同时定点调查了样点单元的麦田害螨种群数量。利用相关性分析明确了影响麦田中两种害螨—麦岩螨(Petrobia latens(Müller))和麦圆叶爪螨(Penthaleus major(Duges))种群发生的主要景观因子。研究结果表明景观因子对麦田中两种害螨种群均有显著影响,而两种害螨对景观因子的响应并不一致。麦岩螨的发生量与森林的最大斑块面积指数和平均斑块面积均呈显著正相关,而与森林类的形状和水体的景观形状指数均存在显著负相关;麦圆叶爪螨的发生量同水体的总面积、斑块面积比例、最大斑块面积指数以及县域范围的平均斑块面积均呈显著负相关,而与水体类的形状呈显著正相关。因此在麦田害螨发生较重的地区,在区域性景观规划时,可以通过优化农田周围的森林和水体管理,不利于其种群发生,从而达到对麦田害螨种群生态调控的目的。