PLOCH: a standardized method for sampling and assessing the biodiversity in ponds

Abstract

ABSTRACT1. As ponds are now recognized as freshwater habitats clearly distinct from lakes and running waters, there is a need for standardized tools for assessing their ecological integrity and status, and particularly their biodiversity.2. A standardized method was developed for sampling and assessing the species richness of ponds. Experiences accumulated in previous studies, together with data gathered from 80 Swiss ponds, provided the basis of the proposed method.3. Five taxonomic groups were chosen as complementary representatives of pond inhabitants: aquatic plants, aquatic Gastropoda, aquatic Coleoptera, adult Odonata and Amphibia.4. To sample aquatic flora, quadrats are located along transects perpendicular to the longest axis of the pond. The number of quadrats is calculated from a relationship with pond area. A nonparametric estimator (Jackknife-1) is used to estimate the true species richness from the observed richness.5. Aquatic invertebrates (Gastropoda, Coleoptera) are collected with a hand net. Sampling is stratified within the dominant habitats. The number of samples is calculated from a relationship with pond area. As with the vegetation, the Jackknife-1 estimator is used to estimate the true species richness.6. The species richness of adult Odonata is assessed using a standardized field survey method combining observations from early and late summer. The species richness is corrected with an abundance-based estimator (Chao1). The species richness of Amphibia is obtained from an exhaustive inventory.7. For the assessment of biodiversity, species richness values derived from measurements are compared to values predicted for conditions that enable a high species richness. Generalized Additive Models are used to predict species richness from environmental predictors characterizing the pond. The ratio of measured richness to predicted richness allows the allocation of a quality status to each pond. Results are divided into five biological quality classes, as recommended in the EC Water Framework Directive (WFD).

The local species richness of Dragonflies in mountain waterbodies: an indicator of climate warming?

“…Th is set represents a broad range of thermal conditions with mean annual air temperature ranging from -2.2°C to 12.1°C (Figure 2). Th e sampling of adult Odonata and the assessment of species richness were standardised and followed the PLOCH method (Oertli et al 2005), for which a representative species list is gathered during two sampling days (at the end of spring and summer). To account for sample-size inadequacies (i.e.…”

“…pond area, depth), watershed characteristics (geology, land use), connectivity (isolation from other waterbodies), and climatic data (air temperature, quantity of precipitations, cloud cover, evapotranspiration, solar radiation). For additional information on sampling procedure and pond characteristics, see Oertli et al (2002Oertli et al ( , 2005.…”

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

“…1 and Table 1). All ponds were sampled in the summer between 1996 and 2005 (one sampling date per pond) with the standardized method developed by Oertli et al (2005). The ponds in this data set varied in size from 6 to 96,200 m 2 (mean: 7,959 m 2 , median: 2,328 m 2 ) and covered an altitudinal range from 210 to 2,757 m.a.s.l.…”

Eutrophication: Impacts of Excess Nutrient Inputs on Aquatic Ecosystem

“…This process naturally occurs in lakes and ponds at a very slow pace as organic matter builds up during ecological succession. However, if eutrophication is accelerated through human activity it can become detrimental to ecosystems [1]. High nutrient levels promote blooms of photosynthetic life, which will eventually die and become food for aerobic bacteria.…”