Biodiversity effects of constructed and restored wetlands – an ecological and socioeconomical approach

(Poster)

Ilona Helle
ilona.h.helle@jyu.fi

Department of Biological and Environmental Science, University of Jyväskylä, Finland
,
Panu Halme
Department of Biological and Environmental Science, University of Jyväskylä, Finland
,
Atte Komonen
Department of Biological and Environmental Science, University of Jyväskylä, Finland
,
Riikka Paloniemi
Finnish Environment Institute (SYKE), Environmental Policy Centre, Green Infrastructure, Finland

DOI: 10.17011/conference/eccb2018/108039

SEE PEER REVIEW

Wetlands are highly productive ecosystems with characteristics of both terrestrial and aquatic ecosystems. They have special biota adapted to inundation by water. Between 1970 and 2008, natural wetlands declined on average by about 30% globally and 50% in Europe. The severe loss of natural wetlands, as well as their degradation by agriculture, forestry and other human activity, has caused declines in natural wetland habitat types and specialized species, for example waterfowl populations in Finland. During the last decade, wetlands have been protected, restored and even constructed to save the diversity of wetland biota. Many studies show that constructed and restored wetlands can provide suitable habitats for waterfowl, waders and other wetland-dependent taxa. However, the biological characteristics of such wetlands often differ from natural ones and the habitat variables of constructed or restored wetlands affect the use of wetlands by waterbirds. My PhD project focuses on the biodiversity of constructed and restored wetlands on agricultural areas. The aims of the project are: 1) to investigate the effects of the characteristics, i.e. size, mean water depth, shoreline length and age of wetlands on vegetation, waterbirds and dragonflies, 2) to study the effects of regional land use and wetland connectivity on waterfowl diversity, densities and wetland suitability as breeding habitat, and 3) to study the motives of landowners to apply for EU-subsidies for wetland construction and the cost-effectiveness of such subsidies. I will present the results of the effects of several habitat characteristics of constructed wetland on waterbirds at 32 constructed agricultural wetlands in boreal zone, Finland. We use orthoimages generated from aerial photographs taken with an unmanned aerial vehicle (quadcopter) to estimate open water area and shoreline length of the sites, belt-line transect quadrat method for defining vegetation structure and standard Finnish waterbird census method for species, pair and brood counts. The results can be applied in cost-efficient construction and restoration of wetlands with high biodiversity values.

SEE PEER REVIEW

INTRO:
In this study on restored and constructed wetlands in an agricultural landscape, the effect of (abiotic) wetland features on vegetation, waterbirds and dragonfly biodiversity is investigated. The authors also consider the effects of regional land use and connectivity of wetland patches on breeding waterbird diversity, density and habitat suitability. Additionally, in a socioeconomical part of the study, the motivation of landowners to apply for EU-subsidies for wetland construction and the effectiveness of these programmes is investigated. The authors will present the results for 32 constructed wetlands in Finland, and propose their results will be valuable for developing cost-effective programmes for constructing and restoring high-biodiversity wetlands.
MERITS:
This study looks at different wetland characteristics, focusing on waterbirds and, to lesser extent, dragonflies as target groups (bio-indicators). It is also relevant that effects of the 'matrix' (agricultural landscape, connectivity) are taken into account. The fact that socio-economical aspects are incorporated is an added value to this study, as these are an important issue in conservation/restoration ecology (yet often not addressed).
CRITIQUE:
The authors mostly take 'shape/size' proxies into account to describe wetlands (shoreline length, wetland size), which are appropriate wetland features in this context, but some other variables may be necessary to describe habitat suitability for waterfowl, such as indicators for food availability and water quality (distinction between habitat use and habitat suitability). It might also be interesting to look at water pollution (e.g. pesticides).
DISCUSSION:
The authors indicate that this research will aid in cost-effective construction and restoration of wetlands with high biodiversity value. I agree that this study, combining information at different levels, can be a valuable step in e.g. identifying drivers for wetland restoration by land owners, but the direct link between this study and such guidelines for 'cost-effective' construction programmes should be made a little more concrete (which targets must be set, and what 'measure' should the targets be based according to the study: waterbird diversity,...). The final sentence remains a bit vague at this instance.

- - -
INTRO:
The manuscript submitted refers to a part of a PhD thesis, in which the effects of artificial and restored wetlands on wetland-dependent species within agricultural landscapes in Finland is studied. Specifically, the author will discuss the results of an analysis of the relationship between waterbird abundance and the features (characteristics) of 32 artificial and restored wetlands in Finland.
MERITS:

The main strength of the study is the relevance of the topic, as conservation actions need to be implemented rapidly. In this sense, the creation of artificial ponds and restoring wetlands is very relevant. In addition, as the funds allocated for conservation are (very) limited, assessments of the cost-effectiveness of such schemes are critical (although this will not be presented, I think).
CRITIQUE:

My only concern here could be the sample size (32 sites) and how these results could be extrapolated to a broader context. The author did not mention either the span of the study period (how long is the time series?).
DISCUSSION:
In my opinion, this study (and the PhD thesis) is very relevant and interesting for several reasons. Waterbird populations breeding in Finland have declined in the past years and. Such population declines have been linked to climate change and the deterioration of natural wetlands. The creation of artificial ponds and restored wetlands has also increased in the past years, either for hunting or conservation purposes. Thus, this study can show the link between waterbird abundance and the type of artificial wetland, which can help future management and conservation actions towards waterbird species, a group of species of conservation concern due to their ecological, societal and economic relevance.