Publication: Floodplain management in temperate regions: is multifunctionality enhancing biodiversity? (Jun 2013)

Floodplain management in temperate regions: is multifunctionality enhancing biodiversity?

The electronic version of this article is the complete one and can be found online at: http://www.environmentalevidencejournal.org/content/2/1/10

Received:	13 August 2012
Accepted:	10 May 2013
Published:	23 May 2013

© 2013 Schindler et al.; licensee BioMed Central Ltd. 

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background

Floodplains are among the most diverse, dynamic, productive and populated but also the most threatened ecosystems on Earth. Threats are mainly related to human activities that alter the landscape and disrupt fluvial processes to obtain benefits related to multiple ecosystem services (ESS). Floodplain management therefore requires close coordination among interest groups with competing claims and poses multi-dimensional challenges to policy-makers and project managers. The European Commission proposed in its recent Biodiversity Strategy to maintain and enhance European ecosystems and their services by establishing green infrastructure (GI). GI is assumed to provide multiple ecosystem functions and services including the conservation of biodiversity in the same spatial area. However, evidence for biodiversity benefits of multifunctional floodplain management is scattered and has not been synthesised.

Methods/design

This protocol specifies the methods for conducting a systematic review to answer the following policy-relevant questions: a) what is the impact of floodplain management measures on biodiversity; b) how does the impact vary according to the level of multifunctionality of the measures; c) is there a difference in the biodiversity impact of floodplain management across taxa; d) what is the effect of the time since implementation on the impact of the most important measures; and e) are there any other factors that significantly modify the biodiversity impact of floodplain management measures? Within this systematic review we will assess multifunctionality in terms of ESS that are affected by an implemented intervention. Biodiversity indicators included in this systematic review will be related to the diversity, richness and abundance of species, other taxa or functional groups. We will consider if organisms are typical for and native to natural floodplain ecosystems. Specific inclusion criteria have been developed and the wide range of quality of primary literature will be evaluated with a tailor-made system for assessing susceptibility to bias and the reliability of the studies. The review is intended to bridge the science-policy interface and will provide a useful synthesis of knowledge for decision-makers at all governance levels.

Keywords: 

Biodiversity; Multifunctionality; Floodplain management; Green infrastructure; European Commission Biodiversity Strategy 2020; Biodiversity knowledge; Ecosystem services; Flood prevention; River restoration; Systematic review; Science-policy interface; Science-practice interface

Background

The European Commission proposed in its recent Biodiversity Strategy to maintain and enhance European ecosystems and their services by 2020 by establishing green infrastructure (GI) and restoring at least 15% of degraded ecosystems [1]. The package of actions designed to respond to this challenge included the need to ensure no net loss of biodiversity and ecosystem services by EU-funded projects, priority setting regarding restoration, and promoting the use of GI [1]. GI is defined as the network of natural and semi-natural areas, features and green spaces in rural and urban, terrestrial, freshwater, coastal and marine areas [2]. This includes for instance areas of high nature value such as protected areas, floodplains, wetlands and natural forests, natural landscape features that can act as corridors for wildlife, artificial features such as eco-ducts or eco-bridges, and multifunctional zones where land uses are favoured that help maintain or restore healthy biodiverse ecosystems [3,4]. The European Commission emphasizes the ability of GI to perform multiple functions in the same spatial area, thus sustaining a range of benefits by delivering multiple ecosystem services (ESS) such as air and water purification and climate regulation [5,6]. ESS represent the benefits human populations derive, directly or indirectly, from ecosystem functions [7], and both functions and benefits might be affected through interventions, such as reconnection of natural areas and improvement of overall ecological quality of the countryside. A combination of the delivery of multiple ESS including the conservation of biodiversity could lead to win-win situations and thus present an efficient way of achieving long-term nature conservation [8]. Knowledge generation to promote understanding of such situations is a current research priority in conservation biology, applied ecology, and environmental sciences [9,10]. Within this systematic review we will assess multifunctionality in terms of ESS that are affected by an implemented intervention.

Floodplains develop adjacent to river channels and can be described as low-relief Earth surfaces composed of fluvial deposits [11,12] that are frequently flooded (active floodplains) or formerly flooded (morphological floodplains) and are an integral part of catchments [13]. While hosting important natural assets and high levels of biodiversity[14-16], they have been used since ancient times by human populations, who attempted to maximize the benefits they gained by interventions such as irrigation channels and dikes [17]. In many parts of the world, human activities have altered the landscape and disrupted fluvial processes to the extent that floodplains are among the world´s most threatened ecosystems [18-20]. Floodplains are good examples for multifunctional landscapes and GI and their management requires close coordination among agriculture, water use, hydrological engineering, mineral extraction, energy production, nature conservation and spatial planning [21] and poses multi-dimensional challenges to policy-makers and project managers [22]. Flood protection is particularly important in light of an increasing frequency and amplitude of flood events throughout Europe, resulting in casualties and damage [23,24]. Restoration of a river and its adjacent floodplain might generate many benefits for nature and society, including alternative economic activities, improved flood prevention, richer biodiversity and aesthetically appealing landscapes and particular recreational opportunities. However, information on implementation and outcomes of such projects is often inaccessible [25].

Evidence for biodiversity effects of the GI approach and particularly of multifunctional floodplain management is scattered and has not been synthesised [21]. This issue is of particular relevance for large lowland floodplains, where due to high human population densities a variety of ecosystem services are in demand while at the same time floodplain biodiversity is driven by dynamic biophysical processes and feedback mechanisms over broad spatial and temporal scales [13,17]. As climate is an important factor for ecological processes, floodplains situated in climates comparable to those occurring in Europe are of particular relevance for this review that aims to support European decision-making. Floodplain interventions are very diverse [26] and in this scientific review we will hierarchically categorize the encountered interventions with respect to their main aims and effects. The interventions also differ strongly regarding the frequency of their implementation and the degree to which their impact on biodiversity has been assessed or results published in accessible formats [25]. This must be considered when interpreting the results of this review. The level of multifunctionality of interventions can be assessed in terms of their effects on ESS. For instance, several restoration measures aiming at a dynamic habitat mosaic are supposed to additionally increase the provision of ESS, such as water purification and lifecycle maintenance, habitat and gene pool protection [13]. Suitable indicators of biodiversity include measures such as the diversity or abundance of species, taxonomic or functional groups [27-30]. The effects of the floodplain management measures on biodiversity will be prone to several factors, the most obvious being the considered taxa and the time since intervention. Floodplain management measures can have very different effects on different taxa, for instance, a water enhancement scheme for the Danube floodplain within the city limits of Vienna showed positive effects on dragonflies and molluscs, while no significant impact was observed for fish [31]. Time since intervention is a crucial parameter, and depending on several factors, such as availability of propagules for population establishment, an intervention might show its effects only after a considerable time span [32].

Objective of the review

In this systematic review we aim to synthesise evidence in response to a two-part primary question dealing with the effects of multifunctional floodplain management on biodiversity. We will further assess three secondary questions dealing with the main causes of heterogeneity in patterns detected.

Primary question

What is the impact of floodplain management measures on biodiversity and how does the impact vary according to the level of multifunctionality of the measures?

The question contains the following components:

Population: floodplains and rivers, including all ecosystems that are located in the morphological floodplain and linked to the hydrological regime of the river.

Intervention: floodplain management measures, commonly related to production and transport (e.g. water or mineral extraction, navigational infrastructure), water regulation and flood protection, conservation and restoration as well as recreation activities (see Methods section for further examples).

Comparator: the previous state of the floodplain before the implementation of the intervention, the original natural state of the floodplain, or the state of the floodplain after another kind of intervention.

Outcome: change in biodiversity indicators (diversity and abundance indicators of species or other groups of organisms).

Secondary questions

a) How does the biodiversity impact of floodplain management differ across taxa?

b) What is the effect of the time since implementation on the impact of floodplain management measures?

c) Which other factors significantly modify the biodiversity impact of floodplain management measures?

Methods

Searches

Database search terms and languages

Three categories of search terms will be applied, corresponding to the categories of the questions, i.e. population, intervention and outcome (Tables  1, 2 and 3). The comparator will not be included for the search itself but as an inclusion criterion. We aim to perform the search in the two main databases for scientific literature, i.e. Scopus and Thomson Reuters Web of Knowledge (formerly ISI Web of Knowledge). The main search terms for each category will be complemented by alternative terms deemed by the review team to have similar significance given the terms have been applied in several key papers [26,33-35]. Among the three categories, the terms will be linked with the Boolean operator ‘AND’. Within the three categories, the terms will be linked with the Boolean operator ‘OR’. In the “outcome-group”, the main search term “biodiversity” will be complemented by a combination of (i) any of the four terms “diversity”, “richness”, “abundance”, and “density” AND (ii) any of many alternative terms for “species”, such as “genus”, “taxon”, “plant”, “tree”, “bird”, “insect”, “macrozoobenthos”, etc. (Table  3). To be considered, studies will have to contain one term for each of the three categories in either title, keywords and abstract or topic for the Scopus or Thomson Reuters Web of Knowledge databases, respectively.

For more information: http://www.environmentalevidencejournal.org/content/2/1/10