Piscart Christophe, Genoel Romuald, Doledec Sylvain, Chauvet Eric, Marmonier Pierre
Université Claude Bernard Lyon 1 - Laboratoire d'Ecologie des Hydrosystèmes Fluviaux - UMR CNRS 5023 - Campus Doua, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne Cedex, France.
Environ Pollut. 2009 Mar;157(3):1011-8. doi: 10.1016/j.envpol.2008.10.010. Epub 2008 Nov 22.
In developed countries, changes in agriculture practices have greatly accelerated the degradation of the landscape and the functioning of adjacent aquatic ecosystems. Such alteration can in turn impair the services provided by aquatic ecosystems, namely the decomposition of organic matter, a key process in most small streams. To study this alteration, we recorded three measures of heterotrophic activity corresponding to microbial hydrolasic activity (FDA hydrolysis) and leaf litter breakdown rates with (k(c)) and without invertebrates (k(f)) along a gradient of contrasted agricultural pressures. Hydrolasic activity and k(f) reflect local/microhabitat conditions (i.e. nutrient concentrations and organic matter content of the sediment) but not land use while k(c) reflects land-use conditions. k(c), which is positively correlated with the biomass of Gammaridae, significantly decreased with increasing agricultural pressure, contrary to the taxonomic richness and biomass of Trichoptera and Plecoptera. Gammaridae may thus be considered a key species for organic matter recycling in agriculture-impacted streams.
在发达国家，农业实践的变化极大地加速了景观的退化以及相邻水生生态系统的功能。这种改变反过来又会损害水生生态系统提供的服务，即有机物质的分解，这是大多数小河流中的一个关键过程。为了研究这种改变，我们沿着对比鲜明的农业压力梯度记录了与微生物水解活性（FDA水解）以及有（k(c)）无（k(f)）无脊椎动物时的落叶分解率相对应的三种异养活性指标。水解活性和k(f)反映局部/微生境条件（即沉积物中的营养浓度和有机物质含量），但不反映土地利用情况，而k(c)反映土地利用条件。k(c)与钩虾科生物量呈正相关，随着农业压力的增加而显著降低，这与毛翅目和襀翅目的分类丰富度和生物量情况相反。因此，钩虾科可能被视为受农业影响溪流中有机物质循环的关键物种。
