A comparative study of macrophyte species richness in differently managed shore stretches of Lake Peipsi

作者：Palmik Kadi^*; Maeemets Helle; Haldna Marina; Kangur Kuelli

来源：Limnologica, 2013, 43(4): 245-253.

DOI：10.1016/j.limno.2012.11.005

• Reed removal
• Shore management
• Macrophyte species richness
• Protected species

We have compared the floristic composition of managed (M) and wild (W) shore areas in the northwestern, eutrophic part of Lake Peipsi (3555 km(2), with unregulated water levels). Management techniques include uprooting or cutting of reeds and willows, building a terraced area between the dunes and the water edge and frequent mowing. In 2006 and 2008, macrophyte species richness was registered summarily for different shore stretches; in 2009-2010, a study on 12 transects, each with 10-15 quadrats of 0.5 m x 0.5 m, was carried out in the same area. In parallel to this, the vegetation in an overgrown inlet near the lake was studied. The aims were: (1) to estimate species richness on managed and wild shore areas and to determine the suitability of managed areas for maintaining declining species and (2) to study the impact of terrace building and duration of management on the vegetation.
In total, 116 herbaceous species were found during the study period. Xero-, meso- and hygrophilous apophytes were characteristic for M (managed) stretches and hydrophilous apophytes for W (wild) stretches. Small threatened amphibious plants and hygrophytes such as Alisma gramineum, Ranunculus reptans, Sagina nodosa, Cyperus fuscus, Eleocharis spp., Juncus spp. were characteristic for the M stretches. The number of species was the highest (average per quadrat 11) in the mowed intermediate zone between the terrace and open water. In the inlet area the number of protected plants was highest in the first study year (2006) and then declined from 5 to 2. The highest total number of species was found in areas under ownership with diverse M and W habitats. Jaccard's similarity coefficients (JSCs) for the whole study area between the years were 0.30-0.50. The calculation of 462 JSCs among all ownerships and transects for the study period yielded floristic similarities of 0-0.59. The year along with style of management seemed to have strongest relationship with higher JSCs, and the yearly changing water levels the most obvious reason for the changes. This study has revealed the contribution of active management towards the support of persistent species richness in conditions of changing water levels, but probably not supporting richness at the more stable water edge.

• 出版日期2013-6