The M-NIP: a macrophyte-based Nutrient Index for Ponds

Abstract

In Swiss ponds, eutrophication represents one of the major threats to biodiversity. A biological method to assess the trophic state would, therefore, be particularly useful for monitoring purposes. Macrophytes have already been successfully used to evaluate the trophic state of rivers and lakes. Considering their colonizing abilities and their roles in pond ecosystem structure and function, macrophytes should be included in any assessment methods as required by the European Water Framework Directive. Vegetation survey and water quality data for 114 permanent ponds throughout Switzerland were analysed to define indicator values for 113 species including 47 with well-defined ecological response to total water phosphorus (TP). Using indicator values and species cover, a Macrophyte Nutrient Index for Ponds (M-NIP) was calculated for each site and assessed with both the original pond data set and a limited validation data set. The resulting index performed better when considering only species with narrow responses to TP gradient and was more applicable, but less accurate when including all species. Despite these limitations, the M-NIP is a valuable and easy tool to assess and monitor the nutrient status of Swiss ponds and was shown to be robust and relatively sensitive to slight changes in phosphorus loading with a validation subset.

ESMI: a macrophyte index for assessing the ecological status of lakes

“…The absolute number of species or communities does not exhibit a clear negative response to eutrophication pressure, as its response curve along the phosphorus gradient was found to be unimodal with the highest number of plant species found in habitats ranging from mesotrophic to eutrophic environments and the lowest in both nutrient-poor and nutrient-rich conditions (Rørslett 1991; Toivonen and Huttunen 1995; Murphy 2002; Penning et al 2008). Quantitative ratios between functional species groups (sensitive to tolerant taxa) are used effectively in many European methods (Schaumburg et al 2004; Penning et al 2008; Sager and Lachavanne 2009), but are of limited value in studies of Polish lakes. Ecosystems with naturally eutrophic, calcium-rich waters are colonised mainly by eurytopic species with a relatively wide ecological amplitude and similar habitat requirements, but they are largely devoid of species that are particularly sensitive to eutrophication, which minimises the effectiveness of the above ratios.…”

What governs macrophyte species richness in kettle hole types? A case study from Northeast Germany

“…This was already done for lakes (Stelzer et al 2005). Recently, standardised assessment tools for ponds were developed Indermuehle et al 2010;Sager and Lachavanne 2009), which consider reference conditions for ponds in general. But existing tools and protection strategies in Germany and other European countries are still inadequately specific with respect to potential habitat functions of kettle hole or pond types.…”

A new method for monitoring macrophyte communities in small shallow lakes and ponds

“…The values obtained with the other 17 SSLs were used for data validation tests. Then, 7 descriptors were selected to identify the effects of the sampling method on macrophyte communities: (1) total floristic richness -a synthetic but quantitative picture of biodiversity -, (2) the Shannon diversity index, (3) the median conservation value according to the national red list, (4) the M-NIP trophic index (Sager and Lachavanne 2009), ( 5) the percent coverage of submerged species (spermatophytes + Characeae + bryophytes + ferns), ( 6) the percentage of exotic species, and ( 7) the richness in 'infrequent species' (difficult to observe because their coverage is < 1% in mapped inventories). The median conservation value was calculated using the species rarity index (SRI) as follows:…”