Weiner Stefan E B
Limnology, Department of Ecology, Lund University, Box 65, S-22100, Lund, Sweden.
Oecologia. 1993 Jun;94(3):451-456. doi: 10.1007/BF00317123.
This study follows the outcome of long-term competition between a broad-leaved and a narrowleaved Typha species, T. latifolia and T. angustifolia respectively, in a eutrophic lake. The lake was bordered by a zone of T. latifolia, at one location interrupted by a T. angustifolia stand. Distributional changes of the T. angustifolia stand and the adjacent zone of T. latifolia were measured on aerial photographs (≤13 years) and along ground-level transects (6 years). A second stand of T. angustifolia was established with transplanted ramets within a formerly homogeneous zone of T. latifolia, and displacement between the two species was measured along ground-level transects after 6 years. Differences between the species in shoot performance were investigated to help explain the relative competitive abilities of the two Typha species. T. angustifolia expanded at the expense of T. latifolia at all water depths where both species occurred, except in very shallow water. Expansion rates suggest that T. angustifolia was not affected by the presence of T. latifolia in water depths exceeding 0.25 m. The Typha species were significantly negatively associated according to rank correlations of shoot densities, and changes of shoot densities, along the transects. These results suggest that T. angustifolia is competitively superior to T. latifolia, contradicting earlier studies. The higher competitive ability of T. angustifolia is consistent with its having taller shoots and a higher standing crop in early summer. Further, shoot height distributions indicated a closer integration of shoot emergence during spring in T. angustifolia than in T. latifolia. A high leaf area/shoot weight ratio suggest that T. latifolia may instead be relatively fast-growing, achieving competitive superiority over narrower-leaved Typha species during a transient period after simultaneous seedling establishment.
本研究追踪了在一个富营养化湖泊中，阔叶香蒲物种（宽叶香蒲）和窄叶香蒲物种（狭叶香蒲）之间长期竞争的结果。该湖泊周边环绕着一片宽叶香蒲带，在一个地点被一片狭叶香蒲林打断。通过航拍照片（≤13年）和地面样带（6年）测量了狭叶香蒲林及其相邻宽叶香蒲带的分布变化。在以前均匀分布的宽叶香蒲区域内，通过移植分株建立了第二片狭叶香蒲林，并在6年后沿着地面样带测量了两个物种之间的替代情况。研究了两个物种在地上部分表现的差异，以帮助解释两种香蒲物种的相对竞争能力。在两个物种共存的所有水深条件下，狭叶香蒲都以宽叶香蒲为代价进行扩张，除了在非常浅的水域。扩张速率表明，在水深超过0.25米时，狭叶香蒲不受宽叶香蒲存在的影响。根据地上部分密度的等级相关性以及沿样带的地上部分密度变化，香蒲物种之间存在显著的负相关。这些结果表明，狭叶香蒲在竞争上优于宽叶香蒲，这与早期研究结果相反。狭叶香蒲较高的竞争能力与其在初夏时具有更高的地上茎和更高的生物量相一致。此外，地上茎高度分布表明，狭叶香蒲在春季地上茎的出苗比宽叶香蒲更加紧密。较高的叶面积/地上茎重量比表明，宽叶香蒲可能生长相对较快，在同时建立幼苗后的一个短暂时期内，比窄叶香蒲物种具有竞争优势。
