天台山森林植被及其利用和保护

一、概况天台山地处东经120°50′—121°24′与北纬29°09′—29°28′之间,在政区上位于浙江省东部,跨天台、新昌、宁海三个县,是仙霞岭的支脉。境内多低丘谷地和山间台地,主峰苍上顶座落在整个山区的南端,海拔1113.4m。在气候分区上,本区属于亚热带中部,为季风气候区。年平均气温16.27℃,最冷月均温5.1℃,最热月均温23.5℃,年降水1320.5mm。山区南部的华顶山常年多雨雾,空气湿度大,年降水达1700mm以上,日均温≥10℃,积温为2858—5157℃,全年生长期长达200—240天。     

后河保护区的珍稀濒危植物

后河自然保护区位于鄂西南五峰土家族自治县境内，北纬３０°０３′至３０°０８′，东经１１０°３０′至１１０°３５′，面积约１万公顷。保护区内海拔最高１９３４ｍ，最低９８０ｍ，整个地势周围高，中间低。区内山峦重叠，沟壑纵横，地形地貌复杂。本区属亚热带气候，年平均气温１３１℃，年积温为３８０７９—４９８４３℃，无霜期约２５０天，年降水量约１４６０ｍｍ，年相对湿度为７６％。该区发育的地带性植被类型为中亚热带常绿阔叶林与落叶混交林。经调查，这里有维管植物２００２种，隶属８１０属１９０科。其中蕨类１９…     

南岳自然保护区爬行动物资源调查

为了调查清楚南岳自然保护区的自然资源概况 ,我们受南岳区政府的委托 ,组织综合考察队于2 0 0 0年 6月至 2 0 0 2年 6月对南岳自然资源进行了考察 ,现将自然保护区的爬行动物资源调查情况报告如下。1　自然概况　　湖南省南岳衡山是一座孤山 ,地处北纬 2 7°2 0′1 0″～ 2 7°1 9′40″,东经 1 1 2°3 4′2 8″～ 1 1 2°45′3 6″,南岳自然保护区总面积为 1 1 991 .6 hm2 ,山体连绵起伏 ,系中同地貌 ,最底海拔 80 m,最高海拔 1 2 89.8m。山脉呈北北东至南南西走向 ,由东北向西倾斜 ,坡度一般为 3 0°～ 40°,南端边缘悬崖地带坡度最大可…     

西藏雅鲁藏布江中游发现黄斑褶[鱼兆]

正2016年4月,在西藏雅鲁藏布江中游干流下段的派镇段(29°31′9″N,94°52′12″E,海拔2 897 m),6月在米林段(29°12′1″N,94°5′16″E,海拔2 947 m),2017年7月在里龙段(29°8′32″N,93°54′34″E,海拔2 960 m),使用定置刺网共捕获到15尾疑似黄斑褶(Pseudecheneis sulcatus)的鱼类标本(图1a,b)。2017年4月在雅鲁藏布江下游墨脱段(29°18′10″N,95°16′52″E,海拔682 m)采集到一批黄斑褶标本(图1c,d),并与中游的黄斑褶进行了形态学比较鉴定。     

古蔺野生植物资源——红子

四川古蔺县地处云贵高原,东径105°34′至106°21′,北纬27°41′至28°41′之间。海拔最低300米,最高1870米,相对高差1500米。年平均气温17.1℃,月平均最高气温26.8℃,最低气温6.8℃、年平均雨量855.6毫米,无霜期230～302.7天。日照1197.9小时以上。山大沟深,土地肥沃,气候温和,虽是边远山区,但无严寒酷暑,最适宜各种野生植物果品资源的生长,特别是红子,遍地皆是,预计产量不少于1500万斤以上。     

万木萧森自然起 人间从此绝烟尘——八大公山国家级自然保护区

八大公山自然保护区位于湘西北的桑植县境内,地处东经109°41′～110°10′,北纬29°38′～29°49′。西接湖北宣恩,北邻湖北鹤峰,东距桑植县城85公里,总面积2.32万公顷,森林蓄积量106.3万立方米。1984年由湖南省人民政府确立为首批23处自然保护区     

用野花美化城市

霍林郭勒市位于内蒙古自治区哲里木盟境内,地处大兴安岭余脉,西靠锡林郭勒盟,南接赤峰市,北邻兴安盟,东与吉林省白城地区接壤。地理坐标东经119°34′北纬45°28′,海拔820—940米。属温带半干旱气候区。冬季严寒,夏季凉爽。积雪日平均210天。年平均气温0.1℃,最热月7月平均气温为35.4℃,极端最低气温 -37.6℃,稳定通过≥10℃积温为1936℃。年降水量平均363.2毫米,多集中于6—8月,年平均降雪为56.4毫米,空气相对湿     

西藏草地类型及其资源评价

一、西藏自然条件概述西藏高原位于北纬27°00′—36°05′,东经78°05′—99°00′内,面积约120万平方公里。境内有东西向和南北向两组大山脉,形成西北高,东南低的地势。在东西向山脉中,由南往北依次有著名的喜马拉雅山、冈底斯山、念青唐古拉山、唐古拉山、喀喇昆仑山和昆仑山。南北向山脉分布在藏东,由伯舒拉岭、他念他翁山等,组成我国著名的横断山区的西半部。境内大部分地区海拔高度在4000米以上,与周围地区相比,相对高差达2000—3000米。这一又高又大的高原,在气候上具有自己的特点;高原内不同地域又有明显分异。(见表一)     

神农架自然保护区两栖爬行动物初步调查

神农架自然保护区位于湖北省西部,东经110°3′—110°34′,北纬31°22′—31°37′。整个区域属大巴山脉东段的延伸部分,南临长江西陵峡,北依汉水。区内最低海拔420米,一般海拔在1700米左右,主峰神农顶海拔3105.4     

云南老君山鼠类的垂直分布

1980年6月至8月,我们对云南老君山的鼠类进行了垂直分布的调查研究。现介绍如下。 自然概况 老君山位于云南省的剑川、丽江和兰坪三县交界处;北纬26°30′—26°52′,东经99°42′—100°26′。属于著名的横断山脉的云岭山系中的大山之一。最高峰海拔4,247m.,山麓(金坪)海拔2,500m.。山势南北走向,北高南低,有纵横交错的高山、山间峡     

Plant species identity and diversity effects on different trophic levels of nematodes in the soil food web

Previous studies on biodiversity and soil food web composition have mentioned plant species identity, as well as plant species diversity as the main factors affecting the abundance and diversity of soil organisms. However, most studies have been carried out under limitations of time, space, or appropriate controls. In order to further examine the relation between plant species diversity and the soil food web, we conducted a three-year semi-field experiment in which eight plant species (4 forb and 4 grass species) were grown in monocultures and mixtures of two, four and eight plant species. In addition there were communities with 16 plant species. We analyzed the abundance and identity of the nematodes in soil and roots, including feeding groups from various trophic levels (primary and secondary consumers, carnivores, and omnivores) in the soil food web.
Plant species diversity and plant identity affected the diversity of nematodes. The effect of plant diversity was attributed to the complementarity in resource quality of the component plant species rather than to an increase in total resource quantity. The nematode diversity varied more between the different plant species than between different levels of plant species diversity, so that plant identity is more important than plant diversity. Nevertheless the nematode diversity in plant mixtures was higher than in any of the plant monocultures, due to the reduced dominance of the most abundant nematode taxa in the mixed plant communities. Plant species identity affected the abundances of the lower trophic consumer levels more than the higher trophic levels of nematodes. Plant species diversity and plant biomass did not affect nematode abundance. Our results, therefore, support the hypothesis that resource quality is more important than resource quantity for the diversity of soil food web components and that plant species identity is more important than plant diversity per se.     

The role of plant species size in invasibility: a field experiment

Large plant species self-thin to disproportionately lower densities than smaller plant species, and therefore may leave more patches of unused space suitable for invasion. Using experimental monocultures of 11 old-field perennial plant species differing in maximum size, as well as mixtures composed of all monoculture species, we tested our primary hypothesis that monocultures of larger species will be more susceptible to natural invasion. After 3 years, monocultures of larger species were invaded by a significantly greater number of species, and more ramets, from the surrounding vegetation. Invading plant species were significantly smaller than the monoculture species being invaded, suggesting that smaller plant species may be better invaders. Thus, we quantified a trade-off between species size, which is frequently associated with increased competitive ability for light, and invasibility, suggesting one reason why large and small species coexist in virtually all plant communities. Although we expected that invasion would enhance biomass production by more fully capturing available resources, we found that the most highly invaded plots of each species produced significantly less biomass. This suggests that increased diversity resulting from invasion did not result in complementary resource use. Mixture plots containing all experimental species did not admit a significantly different number of invading ramets or species than most monocultures, indicating no obvious role for diversity in resistance to invasion, or complementary resource use. Our results suggest that relatively large species may be limited in their capacity to competitively exclude other, smaller species from communities because pure stands of the former are more susceptible to invasion by the latter.     

The naturalization to invasion transition: Are there introduction‐history correlates of invasiveness in exotic plants of Australia?

Of the large number of exotic plant species that become naturalized in new geographic regions, only a subset make the transition to become invasive. Identifying the factors that underpin the transition from naturalization to invasion is important for our understanding of biological invasions. To determine introduction‐history correlates of invasiveness among naturalized plant species of Australia, we compared geographic origin, reason for introduction, minimum residence time and growth form between naturalized non‐invasive species and naturalized invasive plant species. We found that more invasive species than expected originated from South America and North America, while fewer invasive species than expected originated from Europe and Australasia. There was no significant difference between invasive and non‐invasive species with respect to reason for introduction to Australia. However, invasive species were significantly more likely to have been resident in Australia for a longer period of time than non‐invasive species. Residence times of invasive species were consistently and significantly higher than residence times of non‐invasive species even when each continent of origin was considered separately. Furthermore, residence times for both invasive and non‐invasive species varied significantly as a function of continent of origin, with species from South America having been introduced to Australia more recently on average than species from Europe, Australasia and North America. We also found that fewer invasive species than expected were herbs and more invasive species than expected were primarily climbers. Considered together, our results indicate a high propensity for invasiveness in Australia among exotic plant species from South America, given that they appear in general capable of more rapid shifts to invasiveness than aliens from other regions. Furthermore, our findings support an emerging global generality that introduction‐history traits must be statistically controlled for in comparative studies exploring life‐history and ecological correlates of invasion success.     

A highly resolved food web for insect seed predators in a species‐rich tropical forest

The top‐down and indirect effects of insects on plant communities depend on patterns of host use, which are often poorly documented, particularly in species‐rich tropical forests. At Barro Colorado Island, Panama, we compiled the first food web quantifying trophic interactions between the majority of co‐occurring woody plant species and their internally feeding insect seed predators. Our study is based on more than 200 000 fruits representing 478 plant species, associated with 369 insect species. Insect host‐specificity was remarkably high: only 20% of seed predator species were associated with more than one plant species, while each tree species experienced seed predation from a median of two insect species. Phylogeny, but not plant traits, explained patterns of seed predator attack. These data suggest that seed predators are unlikely to mediate indirect interactions such as apparent competition between plant species, but are consistent with their proposed contribution to maintaining plant diversity via the Janzen–Connell mechanism.     

Application of a 15N tracer to simulate and track the fate of atmospherically deposited N in the coastal forests of the Waquoit Bay Watershed, Cape Cod, Massachusetts

The central grassland region of the United States encompasses major gradients in temperature and precipitation that determine the distribution of plant life forms, which in turn may influence key ecosystem processes such as nutrient cycling and soil organic matter dynamics. One such gradient is the threefold increase in precipitation from the eastern Colorado shortgrass-steppe, in the rain shadow of the Rocky Mountains, to the tallgrass prairie in eastern Kansas. We investigated the relative roles of plant species and plant cover in influencing soil C and N cycling in three sites along this gradient. Plant cover (i.e., the presence or absence of an individual plant) was relatively more important than plant species in explaining variability in soil properties at the dry site, the Central Plains Experimental Range in␣northeastern Colorado. However, plant species explained relatively more of the variability in soil properties than did plant cover at the two wetter sites, Hays and Konza, in central and eastern Kansas. The wetter sites had more continuous plant cover, resulting in less plant-cover-induced variation in soil C and N, than did the dry site, which had distinct patches of bare ground. Plant species at the wetter sites had higher and more variable levels of tissue C:N than plant species at the dry site, due to both within species changes and changes in species composition. Aboveground tissue C:N was better correlated with net nitrogen mineralization rates at the wet sites than the dry site. Thus, tissue chemistry appears to exert more control on nitrogen dynamics at the wet than the dry sites. The results suggest that plant species traits that are relevant to nutrient cycling (e.g., tissue C:N ratios, spatial patterns, productivity) reflect environmental limitations as well as species' physiological potentials. Furthermore, a dominant environmental driver such as precipitation may ameliorate or exaggerate the importance of individual species traits for nutrient cycling. Received: 11 July 1996 / Accepted: 5 December 1996     

Native and non‐native grasses generate common types of plant–soil feedbacks by altering soil nutrients and microbial communities

Soil conditioning occurs when plants alter features of their soil environment. When these alterations affect subsequent plant growth, it is a plant soil feedback. Plant–soil feedbacks are an important and understudied aspect of aboveground–belowground linkages in plant ecology that influence plant coexistence, invasion and restoration. Here, we examine plant–soil feedback dynamics of seven co‐occurring native and non‐native grass species to address the questions of how plants modify their soil environment, do those modifications inhibit or favor their own species relative to other species, and do non‐natives exhibit different plant–soil feedback dynamics than natives. We used a two‐phase design, wherein a first generation of plants was grown to induce species‐specific changes in the soil and a second generation of plants was used as a bioassay to determine the effects of those changes. We also used path‐analysis to examine the potential chain of effects of the first generation on soil nutrients and soil microbial composition and on bioassay plant performance. Our findings show species‐specific (rather than consistent within groups of natives and non‐natives) soil conditioning effects on both soil nutrients and the soil microbial community by plants. Additionally, native species produced plant–soil feedback types that benefit other species more than themselves and non‐native invasive species tended to produce plant–soil feedback types that benefit themselves more than other species. These results, coupled with previous field observations, support hypotheses that plant–soil feedbacks may be a mechanism by which some non‐native species increase their invasive potential and plant–soil feedbacks may influence the vulnerability of a site to invasion.     

Plant species richness,identity and productivity differentially influence key groups of microbes in grassland soils of contrasting fertility

The abundance of microbes in soil is thought to be strongly influenced by plant productivity rather than by plant species richness per se. However, whether this holds true for different microbial groups and under different soil conditions is unresolved. We tested how plant species richness, identity and biomass influence the abundances of arbuscular mycorrhizal fungi (AMF), saprophytic bacteria and fungi, and actinomycetes, in model plant communities in soil of low and high fertility using phospholipid fatty acid analysis. Abundances of saprophytic fungi and bacteria were driven by larger plant biomass in high diversity treatments. In contrast, increased AMF abundance with larger plant species richness was not explained by plant biomass, but responded to plant species identity and was stimulated by Anthoxantum odoratum. Our results indicate that the abundance of saprophytic soil microbes is influenced more by resource quantity, as driven by plant production, while AMF respond more strongly to resource composition, driven by variation in plant species richness and identity. This suggests that AMF abundance in soil is more sensitive to changes in plant species diversity per se and plant species composition than are abundances of saprophytic microbes.     

Termite (Insecta: Isoptera) Species Composition in a Primary Rain Forest and Agroforests in Central Amazonia

Termites play important roles in organic matter decomposition, nutrient cycling, and soil structure in tropical rain forests. When forests are replaced by agriculture, termite species richness, abundance, and function often decline. We compared the termite assemblage of a primary forest site with that of a low plant diversity, palm-based agroforest (five plant species) and a high plant diversity, home-garden agroforest (10 plant species) using a rapid biodiversity assessment protocol. In comparing the primary forest termite species composition to previously published studies, we found soil feeders and the Apicotermitinae to be more dominant than previously reported in Amazonia. Thirty percent of the species belonged to the Apicotermitinae, and an unusually high percentage (57%) of species were soil feeders. Unexpectedly, the palm-based agroforest, despite its lower plant diversity, was closer to primary forest in termite species composition, rate of species accumulation, and proportions of species in taxonomic and functional classes than was the home-garden agroforest. This suggests that particular plant attributes may better determine the termite assemblage than plant diversity alone in these agroecosystems. Unlike other agroecosystems reported in the literature, Apicotermitinae and soil feeders were proportionally more abundant in these agroforests than in primary forest. The ability of agroforests to support populations of soil feeders has a potentially positive effect on soil fertility in these agroecosystems; insomuch as feeding guild is a proxy for function, these closed-canopy agroforests may be able to sustain the same termite-mediated functions as primary forest.     

The cobblers stick to their lasts: pollinators prefer native over alien plant species in a multi-species experiment

The majority of plant species rely, at least partly, on animals for pollination. Our knowledge on whether pollinator visitation differs between native and alien plant species, and between invasive and non-invasive alien species is still limited. Additionally, because numerous invasive plant species are escapees from horticulture, the transition from human-assisted occurrence in urbanized habitats to unassisted persistence and spread in (semi-)natural habitats requires study. To address whether pollinator visitation differs between native, invasive alien and non-invasive alien species, we did pollinator observations for a total of 17 plant species representing five plant families. To test whether pollinator visitation to the three groups of species during the initial stage of invasion depends on habitat type, we did the study in three urbanized habitats and three semi-natural grasslands, using single potted plants. Native plants had more but smaller flower units than alien plants, and invasive alien plants had more but smaller flowers than non-invasive alien plants. After accounting for these differences in floral display, pollinator visitation was higher for native than for alien plant species, but did not differ between invasive and non-invasive alien plant species. Pollinator visitation was on average higher in semi-natural than in urbanized habitats, irrespective of origin or status of the plant species. This might suggest that once an alien species has managed to escape from urbanized into more natural habitats, pollinator limitation will not be a major barrier to establishment and invasion.