Assessing the Benefits of Forested Riparian Zones: A Qualitative Index of Riparian Integrity Is Positively Associated with Ecological Status in European Streams

Abstract

Developing a general, predictive understanding of ecological systems requires knowing how much structural and functional relationships can cross scales and contexts. Here, we introduce the CROSSLINK project that investigates the role of forested riparian buffers in modified European landscapes by measuring a wide range of ecosystem attributes in stream-riparian networks. CROSSLINK involves replicated field measurements in four case-study basins with varying levels of human development: Norway (Oslo Fjord), Sweden (Lake Mälaren), Belgium (Zwalm River), and Romania (Argeş River). Nested within these case-study basins include multiple, independent stream-site pairs with a forested riparian buffer and unbuffered section located upstream, as well as headwater and downstream sites to show cumulative land-use impacts. CROSSLINK applies existing and bespoke methods to describe habitat conditions, biodiversity, and ecosystem functioning in aquatic and terrestrial habitats. Here, we summarize the approaches used, detail protocols in supplementary materials, and explain how data is applied in an optimization framework to better manage tradeoffs in multifunctional landscapes. We then present results demonstrating the range of riparian conditions present in our case-study basins and how these environmental states influence stream ecological integrity with the commonly used macroinvertebrate Average Score Per Taxon (ASPT) index. We demonstrate that a qualitative index of riparian integrity can be positively associated with stream ecological status. This introduction to the CROSSLINK project shows the potential for our replicated study with its panoply of ecosystem attributes to help guide management decisions regarding the use of forested riparian buffers in human-impacted landscapes. This knowledge is highly relevant in a time of rapid environmental change where freshwater biodiversity is increasingly under pressure from a range of human impacts that include habitat loss, pollution, and climate change.

Relationship between Environmental Conditions and Structure of Macroinvertebrate Community in a Hydromorphologically Altered Pre-Alpine River

“…The proportion of taxa from the orders Ephemeroptera, Plecoptera and Trichoptera is also known as the proportion of EPT taxa or simply EPT. Average score per taxon (ASPT) values were also derived, as described in Monaghan and Soares [37] and Burdon et al [38] to detect potential loading with organic matter, which could influence the macroinvertebrate community structure. Correlations between explanatory variables and the structure of the macroinvertebrate community were tested with a Kendall tau rank correlation coefficient.…”

“…Błachuta et al [55] report that ASPT is most susceptible to water flow, while Monaghan and Soares [37] report that ASPT is positively correlated with flow velocity and substrate diversity. Surprisingly, Burdon et al [38] found that ASPT is negatively influenced by improving riparian condition. However, we failed to find a significant correlation between ASPT and human alterations of riparian zone or morphological conditions.…”

“…Cortes et al [66] emphasize the importance of including different scales to represent the variability of aquatic communities efficiently. Moreover, González del Tánago et al [67] and Burdon et al [38] emphasize that exploring hydromorphological indicators across spatial scales (e.g., the share of forest in the catchment area, the width of the riparian zone and the channel, the presence of natural retention structures) is an essential step towards the design of sustainable river management.…”

Assessment of physical condition and anthropogenic disturbance of streams of the northcentral United States

“…Intact habitat along the 100-m riparian mask of streams, while more abundant in northern MI, MI, and WI, was considerably more evenly distributed throughout the study area than was upstream habitat. Riparian buffers are frequently employed to mitigate the effects of agricultural input, and are frequently the only remaining forested habitat in agricultural watersheds (Craig et al 2008;Burdon et al 2020).…”

Diagnostic Evaluation and Preparation of the Reference Information for River Restoration in South Korea

“…The range and status of riparian vegetation is not only related to the integrity index of rivers evaluated through the macroinvertebrate index, which was commonly used, but also affects the overall of the riverine landscape attributes. In this respect, the management of the riparian vegetation is of paramount importance to conserve biodiversity in river ecosystems at a time of rapid environmental change and increasing pressure from a range of human influences, including habitat loss, pollution, and climate change [42].…”