HYDROLOGIC INFLUENCES ON INSECT EMERGENCE PRODUCTION FROM CENTRAL PLATTE RIVER WETLANDS
HYDROLOGIC INFLUENCES ON INSECT EMERGENCE PRODUCTION FROM CENTRAL PLATTE RIVER WETLANDS
复制标题
水文对中央普拉特河湿地昆虫出苗生产的影响
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
B. S. Goldowitz
中科院分区：
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作者：
M. Whiles;B. S. Goldowitz
淡水生态系统的物理模板对生物群落和过程具有普遍的影响。为了考察水文学对湿地昆虫群落的影响，我们量化了普拉特河流域中部五个河岸泥泞中的昆虫出现情况。湿地的年水期在94~365d/年之间，干旱事件发生的频率和幅度与水期长度成反比。从1997年4月到11月，在每个湿地放置了3个紧急捕捉器。在诱捕器中收集的大多数昆虫被鉴定为属，并测定了个体干重(DM)。浮游昆虫丰度(2 4 12 4头/m2)和羽化产量(5.1g DM·m−2·yr−1)最高，中间水期为2 96 d，水期越长和越短，羽化丰度和羽化产量越低。常年养鱼的多年生站点的出苗产量仅为0.26g DM·m−2.yr−1。摇蚊、库蚊科和姬蜂科是生物量的主要贡献者，而珊瑚科和蝇科是大多数地点生物量的重要贡献者。
二次方程最好地描述了类群丰富度与年水期(R2=0.78，P<；0.05)或干燥事件数/年(R2=0.81，P<；0.05)之间的关系，反映了两者的中间水平的丰富度的峰值。这些关系遵循中间干扰假说的预测，但模式背后的具体机制很难辨别。与羽化产物一样，类群丰富度在中期水期也最高。因此，昆虫多样性(以丰富度衡量)与羽化产量呈正相关(R2=0.85，P<；0.05)。结果表明，普拉特河中部湿地的水文条件对昆虫物种丰富度和羽化产量有很大影响，间歇点的昆虫多样性最高，羽化昆虫生物量最大。然而，本研究中季节性涌现模式的趋势和跨水文梯度的分类变化表明，包含不同水文特征的湿地镶嵌的景观将在更大的空间和时间尺度上最大化水生昆虫多样性和生产力。
The physical template of freshwater ecosystems has a pervasive influence on biological communities and processes. To examine the influence of hydrology on wetland insect communities, we quantified insect emergence from five riparian sloughs in the central Platte River valley. Annual hydroperiods of the wetlands ranged from 94 to 365 d/yr, and frequency and magnitude of drying events were inversely proportional to hydroperiod length. Three emergence traps were placed in each wetland from April through November 1997. Most insects collected in traps were identified to genus, and individual dry mass (DM) also was determined. Abundance of emerging insects (24 124 individuals/m2) and emergence production (5.1 g DM·m−2·yr−1) were highest from the site with an intermediate hydroperiod of 296 d. Sites with longer and shorter hydroperiods had lower emergence abundance and production. Emergence production from the perennial site, which contained fish year-round, was only 0.26 g DM·m−2·yr−1. Diptera generally dominated emergence trap catches. Chironomidae, Culicidae, and Ceratopogonidae were among the dominant contributors to abundance, whereas Sciomyzidae and Muscidae were important contributors to biomass at most sites.
Quadratic equations best described relationships between taxa richness and annual hydroperiod (r2 = 0.78, P < 0.05) or number of drying events/yr (r2 = 0.81, P < 0.05), reflecting a peak in richness at intermediate levels of both. These relationships followed predictions of the intermediate disturbance hypothesis, but specific mechanisms underlying patterns were difficult to discern. Like emergence production, taxa richness was also highest at intermediate hydroperiods. Hence, insect diversity (measured as richness) and emergence production were positively correlated (r2 = 0.85, P < 0.05). Results indicate that the hydrology of central Platte River wetlands exerts a strong influence on insect species richness and emergence production, and that intermittent sites harbor the highest insect diversity and produce more emergent insect biomass. However, trends in seasonal emergence patterns and taxonomic shifts across the hydrologic gradient in this study suggest that a landscape containing a mosaic of hydrologically distinct wetlands will maximize aquatic insect diversity and productivity at larger spatial and temporal scales.