Colonisation by midges (Chironomidae, Diptera) of recently-created shallow ponds: implications for the restoration of lacustrine fringing wetlands

Abstract

-As part of a wetland conservation programme for the Southern shore of lake Neuchatel (Western Switzerland), an experiment was started in 1993 to slow down the terrestrialization of the wetland. Sediments were removed in a reed-belt adjacent to an existing pond, at three different depths (0.20, 0.30 and 0.40 m), thus creating a new shallow pond. The colonisation by aquatic vegetation and invertebrates was monitored during three years (1994)(1995)(1996) to evaluate the effect of the creation of a new pond on the chironomid diversity and abundance through time. Chironomids (78 taxa) were among the most diverse group colonising this fringing wetland. Significant differences in abundance were found between the reed-belt and the pond habitats (existing and recently created ponds). As expected, the latter was more productive, especially during the first two years of colonization. However, the chironomid diversity in the newly created pond, measured by the rarefied richness, was intermediate between the reed-belt (low diversity) and the pre-existing pond. Ordination of the sites on the basis of their chironomid assemblages confirmed this trend. The depth at which the sediment was scrapped off, had no major influence upon the chironomid assemblages. Finally, within the three years after creation of open water habitats, the production of chironomids and consequently their availability for dabbling ducks and wetland birds, were enhanced. However, this time was not enough for the chironomid community to reach the diversity of the pre-existing pond, to which it is connected. The creation of shallow ponds seemed to be crucial to slow down terrestrialization processes in this lacustrine wetland and to have only slight effects on the chironomid communities.

How do early successional patterns in man-made wetlands differ between cold temperate and Mediterranean regions?

“…Since newly created wetlands are mainly colonized by active dispersers, both in the temperate (Koskenniemi 1994;Herrmann et al 2000;Lods-Crozet and Castella 2009) and Mediterranean regions (Ruhí et al 2009), differences in the amount of time available for active dispersal between these regions may be reflected in different successional patterns. Moreover, climate may affect the relative role of deterministic and stochastic assembly mechanisms (Milner et al 2008).…”

Fen ecosystem responses to water‐level fluctuations during the early and middle Holocene in central Europe: a case study from Wilczków, Poland

“…Chironomidae seem to be especially abundant in seasonal, newly emerged and degraded habitats as they are ubiquitous first colonizers (Bataille & Baldassarre ; Brady et al . ; Lods‐Crozet & Castella ).…”

Drought effects on the colonization of benthic macroinvertebrate communities in the early successional phases in experimental mesocosm wetlands

“…Most aquatic Coleoptera live in water during their entire life history, and possess the ability to actively escape from drought in the volitant imaginal stages, except for the larval stage in spring (Wiggins et al 1980;Merritt et al 2008). Chironomids, in particular, the subfamily Chironominae also belong to one of the most abundant early colonizers of newly created or rewetted wetlands (Lods-Crozet & Castella 2009;Kim et al 2014). They, however, sensitively react to drought disturbance depending on various environmental parameters, such as wet phase, oxygen, and organic matter contents (Bazzanti et al 1997).…”