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Communication Dans Un Congrès Année : 2021

Soil bioengineering for riverbank protection, what benefits for biodiversity?

Résumé

Riparian zones have disproportional ecological importance relative to their size, encompassing a large biodiversity and fulfilling major ecological functions. Despite their high ecological value, riparian zones have been widely degraded around the world through urbanization, channelization or damming. When channel mobility cannot be restored, and when erosion control measures are necessary to protect human stakes, different solutions exist to stabilize riverbanks. Civil engineering techniques such as riprap have been widely used along riverbank leading to high human impacts on these ecosystems. Soil bioengineering techniques have been shown to advantageously replace or complete civil engineering techniques, providing compromise solutions to simultaneously ensure protection against erosion and support riparian biodiversity. However, how similar are banks stabilized by soil bioengineering techniques compared to natural banks and to those stabilized by civil engineering is still poorly known. During the last two decades, research efforts have been made to understand how and how much soil bioengineering techniques could increase riparian habitat quality to foster aquatic and terrestrial biodiversity. Here we present results from more than one hundred riparian zones including natural and stabilized riverbanks in France and Quebec in which we assessed biodiversity. We choose a human impact gradient ranging from natural bank to riprap, including pure soil bioengineering techniques and mixed techniques (mixing civil and bioengineering). For riparian plants and benthic macroinvertebrates, soil bioengineering techniques showed higher taxa diversity than civil engineering techniques, mostly related to an increase in habitat quality. Species composition on soil bioengineering techniques was also closer to the one of natural banks, with an increase in native benthic macroinvertebrates richness from civil engineered to soil bioengineering techniques. Considering ecological succession, riprap showed extremely low dynamics, whereas soil bioengineering techniques triggered a secondary ecological succession with an increase of native and hydrochorous riparian plant species over time. Regarding exotic species, the trend was less pronounced, but some evidence of a higher cover of terrestrial invasive plant species on riprap techniques was found. Overall, our results support previous studies showing positive effects of soil bioengineering on fishes and birds communities as compared to civil engineering. Further studies are needed to evaluate how soil bioengineering can affect other biodiversity components such as terrestrial insects, small mammals or amphibians. It would be also interesting to see if the positive effects of soil bioengineering on riparian biodiversity shown in temperate zones occur under other climatic influences.
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Dates et versions

hal-03413933 , version 1 (05-11-2021)

Identifiants

  • HAL Id : hal-03413933 , version 1

Citer

André Evette, Philippe Janssen, Maxime Tisserant, Eduardo González, Bérenger Bourgeois, et al.. Soil bioengineering for riverbank protection, what benefits for biodiversity?. 5th international conference on Soil, Bio- and Eco-Engineering, Jun 2021, Bern, Switzerland. ⟨hal-03413933⟩
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