Effect of Range Condition on Density and Biomass of nematodes in a Mixed Prairie Ecosystem.
Effect of Range Condition on Density and Biomass of nematodes in a Mixed Prairie Ecosystem.
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范围条件对混合草原生态系统中线虫密度和生物量的影响。
DOI：
10.2307/3898658
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
J. K. Lewis
中科院分区：
文献类型：
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作者：
J. Smolik;J. K. Lewis
线虫密度和生物量是由来自南达科他州西部优良或一般范围条件下围栏的分类群确定的。两种处理中的植物取食线虫密度在200万至600万/m* 之间变化，深度为60 cm。在优良条件范围内，植物饲养者的生物量更大，主要是由于大量的匕首线虫。在公平的范围条件下，生物量esthnates的主要贡献者是Tyknchiia，主要是矮化和螺旋线虫。捕食型的生物量与植食型的生物量相似。微生物饲养，虽然众多，构成了一个相对较小的比例，在两个治疗的生物量。在两种范围条件下，约70%的线虫在所有营养kvels发生在20厘米以上的采样深度。矮化线虫几乎仅限于土壤上部10 cm，螺旋线虫占主导地位，随着深度的增加，特别是在公平的条件范围。结果表明，线虫构成了一个混合草原生态系统中的动物区系生物量的主要部分。土壤线虫在大平原州天然草原中的作用很少受到调查。Orr和Dickerson（1967）、Thorne和Malek（1968）、施密特和Norton（1972）、Thorne（1974）以及Norton和施密特（1978）的研究证实了植物寄生线虫是这些草地的重要组成部分。在南达科他州西部，杀线虫剂处理导致原生范围的生长增加28%至59%（Smolik 1977）。新西兰也有证据表明线虫可能限制牧草产量（Yeates 1977）。Yuen（1966）、Wasilewska（1974）、Yeates（1974）、Smolik和Rogers（1976）以及Freckman等人（1979）对其他草地生态系统中的食草线虫进行了研究。本研究的目的是确定范围条件和深度的采样线虫密度和生物量超过6年的研究期的影响。计划进一步分析，以调查其他非生物因素对线虫种群的影响。
Nematode density and biomass were determined by taxa from exclosures in excelknt or fair range condition in western South Dakota. Density of plant feeding nematodes in both treatments varied from 2 to 6 million/m* to a depth of 60 cm. Biomass of plant feeders was greater in the excellent condition range due principally to high numbers of dagger nematodes @rhnarilyX&~ine#na americanum). The main contributors to biomass esthnates in fair range condition were Tyknchiia, principally stunt and spiral nematodes. Biomass of predaceous forms was similar to that of plant feeders. Microbial feeders, although numerous, constituted a relatively small proportion of biomass in both treatments. Approximately 70% of nematodes in all trophic kvels occurred above 20-cm sampling depth in both range conditiom. Stunt nematodes were nearly limited to the upper 10 cm of soil, with spiral nematodes predominating with increasing depth, particularly in fair condition range. Results indicate that nematode constitute a major portion of the faunistic biomass in a mixed prairie ecosystem. The role of soil-inhabiting nematode in native grasslands of the Great Plains states has received little investigation. Studies by Orr and Dickerson (1967), Thorne and Malek (1968), Schmitt and Norton (1972), Thorne (1974), and Norton and Schmitt (1978) have established the fact that plant parasitic nematodes are important components of these grasslands. In western South Dakota nematicide treatments resulted in growth increases ranging from 28 to 59% in native range (Smolik 1977). There is also evidence from New Zealand that nematodes may be limiting pasture production (Yeates 1977). Plant-feeding nematodes in other grassland ecosystems have been investigated by Yuen (1966), Wasilewska (1974), Yeates (1974), Smolik and Rogers (1976), and Freckman et al. (1979). The objectives of this study were to determine the effects of range condition and depth of sampling on nematode density and biomass over a 6-year study period. Further analyses are planned to investigate the effects of other abiotic factors on nematode populations.