caddis and case image- 信用萨姆·琼斯/约克大学
Benthic stream invertebrates are among the best known indicators. They tell us almost immediately how pure freshwater is and exactly how many of our rivers are recovering from any pollution. These canaries in the coal mine are thriving surprisingly well in the low pH of streams in the English North Yorkshire Moors. Sam Jones and Peter J Mayhew, appropriately at the University of York, publish a very interesting twist on this usage in the journal,内陆水域
asA comparison of upland stream invertebrates in moorland and coniferous woodland in North York Moors National Park, UK.
Areas of these moors in the past and present have been subjected to sheep farming, with peat bogs and treeless landscapes while Romans and Vikings have used the countryside almost as much as current industries and private owners. The acid conditions were not expected to be changed by acres of forestry in the form of coniferous planting. This paper however disputes the further acidification by pine and spruce.
16 streams in the east of this very acidic area showed the researchers a greater diversity of benthic stream animals than expected. This of course indicates a lack of pollution and a higher pH than was thought to exist within the streams. pH8 is a reliably alkaline pH that many river watchers would hope for, while the neutral pH of pH7 would be adequate for life to continue in most freshwater. The North York Moors National Park can be expected to have improved the lives of fauna and flora on the moors, but the water quality seems to have been improved by coniferous plantations, instead of reducing the pH. The Forestry Commision indeed have stopped planting streamside and created log dams to help invertebrates to resist being washed away by increased rainfall. The trees obviously increase the input of various material into the stream. This could benefit several invertebrateguilds.
Caddis flies need to build cases, while predators could receive greater numbers of land-based prey organisms.
平均而言，Moorland和Woodland溪流具有相同的pH。底栖无脊椎动物是PH7动物区系的典型特征。踢脚的采样揭示了Mayfly，Caddis和Stonefly若虫，虫子，苍蝇和甲虫的特征，甲壳类和蜗牛。49个不同的动物组表示生物多样性水平，但在物种水平上，出现了更多。但是，林地的某些溪流确实具有更大的生物多样性。尽管Chirinomid（Midge）幼虫占据了Moorland的占主导地位，但它们周围的占主导地位覆盖着，几乎与Baetid（Mayfly），Leuctrid（Stonefly）和Siphloneurid和siphloneurid and polycentropodid（Caddis）nymphs相等。卡迪斯，Odontocerum albicornewas an unexpected find at Hipperley Beck, being acid sensitive, while the fast-flow mayfly,Ecdyonurus torrentis,还有其他一些人在场以确认水质。
We rarely look at rivers or streams, but the use of indicator organisms in fossil fauna was particularly involving here, withdragonflies and mayflies that can be used to indicate past conditions in our precious freshwater.
