采煤沉陷区苦草的生物学特性及其竞争机制

采煤活动所致的动态沉陷湿地具有动态性、高潜水位和生态脆弱性等特点,探明此类人工重构湿地的水生植物群落的生物学特性及其竞争机制,有助于为采煤沉陷区湿地水生植物群落修复提供科学依据。本研究以淮南潘集区人工构建的苦草群落(Ass. Vallisneria natans)为例,采用样方调查法,研究苦草的生物学特性及其与其他水生植物的竞争机制。结果表明,1)沉陷区苦草的生物学特性与浅水湖泊较一致。主要表现在苦草的繁殖方式、传粉方式、生活史方面,但研究区苦草以有性繁殖为主。2)沉陷区苦草能与以种子萌发形成的水烛群丛(Ass. Typha angustifolia)共生,但生物量低;在与形成两年以上的水烛群丛竞争中处于劣势,在水烛群丛盖度达到90%时苦草逐渐消失。3)沉陷区苦草在与浮叶植物莕菜群丛(Ass. Nymphoides peltatum)、苹群丛(Ass. Marsilea quadrifolia)竞争中处于弱势,其盖度、株高、生物量等指标都明显下降。4)沉陷区苦草在与沉水植物竹叶眼子菜群丛(Ass. Potamogeton malaianus)竞争中处于劣势,苦草与沉水植物黑藻群丛(Ass. Hydrilla verticillata)、狐尾藻群丛(Ass. Myriophyllum verticillatum)、大茨藻群丛(Ass. Najas marina)、金鱼藻群丛(Ass. Ceratophyllum demersum)占据不同水层空间,种间竞争不强烈,能较好地共存。总之,苦草较之于相似生长型的植物具有较明显的竞争优势,对于具有不同生活型,尤其是挺水植物和浮叶植物,处于竞争劣势。

Biological traits and competition mechanism of Vallisneria natans in the mining subsidence area

The mining subsidence wetland has obvious characteristics of dynamic, high ground-water level and ecological frangibility. Exploring the biological characteristics and competition mechanism of artificially constructed aquatic plant community is beneficial to recover aquatic vegetation in mining subsidence wetland. This study takes the dominant species of Vallisneria natans as an example to analyze its biological traits and competition mechanisms in Panji District of Huainai City by means of field survey and sampling quadrat investigation. The results showed that V. natans in subsidence area have same biological characteristics (reproductive pattern, pollination mechanism and life history) as plants in shallow lakes, but sexual reproduction was the dominant reproduction way for V. natans in study area. V. natans could grow with current-year Ass. Typha angustifolia community with low biomass; however, V. natans has a competitive disadvantage with two or more years Ass. T. angustifolia community and V. natans would gradually disappeared when coverage of T. angustifolia was ≥90%. V. natans had poor competitiveness with floating plant Ass. Nymphoides peltatum and Ass. Marsilea quadrifolia in mining subsidence area with coverage, plant height and biomass decreasing. V. natans also had poor competitiveness with submerged plants Ass. Potamogeton malaianus while could coexist well with Ass. Hydrilla verticillata, Ass. Myriophyllum verticillatum, Ass. Najas marina, and Ass. Ceratophyllum demersum by inhabiting different water layers. In conclusion, V. natans have obvious competition advantages at the aquatic plant community in identical water layer with similar growth form, while poorly compete to plants with different growth form, especially emerged plants and floating plants.