Optimising the configuration of woody riparian buffer strips along rivers to enhance biodiversity and ecosystem services (Oscar)

Informations

Funding country

Norway

Acronym

-

URL

-

Start date

1/1/2017

End date

12/31/2020

Budget

135,300 EUR

Fundings

Abstract

Effects of riparian woodland on ecosystem service delivery by the river corridor Under natural conditions, river valleys would have large areas of woodland. Millennia of human use have changed this drastically and now often only fragments of riparian forests remain. Those remaining floodplains with extensive forests are generally biodiversity hot spots. Currently, riparian buffer strips are implemented across Europe, mainly as a measure to reduce diffuse nutrient loading to rivers from adjacent agricultural land, but they are not necessarily having trees. These strips can serve as migration corridors for wildlife, connecting different near-natural sites in a green infrastructure network. Also, when wooded, these strips may directly influence the stream environment by offering shade thus moderating water temperature, by subsidizing the food web with organic matter in the form of branches and leaves, and by offering a wide range of habitats. However, the sum of all these effects is poorly quantified and uncertain, particularly when seen at the larger landscape scale where the spatial pattern can be crucial. Different ecosystem functions may be beneficial to human society in different ways, but they may augment or counteract each other. The ecosystem services approach attempts to integrate such different societal benefits and take the complexity of their interaction into account. We have developed the Finnish cascade approach in this project and combined it with articulate down-scaled scenarios for 2050. Our main findings are: (a) In the current state, the quantified services show optimum curves with increasing woodland cover: provisioning services and cultural services were maximal around 45%, whereas this was around 30% for regulating services. Averaged across rivers, mean total service provision was estimated at 1084 ± 4 ? ha-1 y-1, with 40, 36 and 24% contributed by respectively provisioning, regulating and cultural services. The most important services based on our monetary estimates were flood prevention, dairy farming, and recreation (including angling). (b) The three different scenarios led to a rather limited change in total ecosystem service delivery, even if mean woodland cover was reduced from 27% to 17% in the pessimistic scenario and increased to 70% in the ambitious scenario for the most extreme case of the Stever. We did find decline of the summed provisioning services with increased woodland cover and an increase in cultural services. This implies a trade-off between these two groups of services. Regulating services did not change that much, because these are dominated by flood prevention in our assessment. (c) One important finding for river management was that the ?best practice? RMP appeared to combine a modest increase in cultural services with a slight increase in provisioning services. This suggests that a compromise could be possible that maintains agricultural or forestry productivity with enhanced appreciation from recreation and biodiversity conservation. We conclude in our paper that ?an ambitious nature conservation objective as in the ambitious RMP appears possible without seriously compromising overall societal benefit.?