Constructed ecosystem services:

the case of hybrid dunes at Barcelona

1-Mimicking natural processes on urban dunes

Last mobile dunes 1980

1992 the first maritime promenade in Spain with dunes as core element of the landscape treatment

Transformations due to urbanization & modification of coastal dynamics

1956

Anthropocene!

2015

1990

2004

2007-16

Disruption of natural longshore sand transport processes

Increasing flood prone beach areas extending more than 3km

Marram grass decay after less than 10 years

Something worrying when is the most relevant dune constructor. We have not found any photograph of dunes without marram grass

Literature describes competition processes and soil patogens as most relevant factor

Probably mechanical sieving impedes the natural sand aeolian transport, but is only one of the relevant factors

The accumulation of dog excreta can also be a problem for a plant which requires oligotrophic soils

Without marram grass and aeolian sand transport, dune relief disappears. No more bare sand and its biodiversity

Pine tree encroachment is another factor of dune habitat reduction

Altered ecosystem but biodiversity still remaining. Still on time to react!

An European project + the Metropolitan Administration of Barcelona

Goals: 1. Learn how to construct urban dunes2. Learn how to manage the huge demand of cultural ecosystem

services of the urban dunes.

Socio-cultural and economic processes

Cartographies of intensity of use along the year

Dune construction from beach sand

Wind is no more constructing dunes, but …

.. still keeps its ability to erode dunes and uproot marram grass

In just 8 weeks marram grass uprooted and invasive species stablished

Determination of prevailing constructing/eroding winds from historic flights and fieldwork

Erosion risk can be mapped along dune structures.

We have developed a new system to transform marram grass plantings in to efficient sand-trapping systems

Marram grass as natural capital (dune builder)

Marram grass as natural capital and core element of a nature based solution

2-Coastal dynamics & decision chain

No dunes, no beach!!

When beach width is not enough to provide a comfort strip

The only official way to protect the coastline is beach nourishment (100,000m3/yr). No long-term strategy

Sand nourishment has not modified the emerged beach profile which keeps vulnerable to flooding

Beach nourishment hasn’t stopped erosion processes

The need of a policy analysis

A decision environment which is not evidence-based

A highly hierarchical, authoritative and unchecked decision process

The most dependent stakeholders without capacity to intervene on the decision-making

process

Time to think on improving the governance environment

3- Ecosystem services concept as an explicit management tool

LIDAR and satellite images has become very precise

A retraslocation of only 6.000m3 of emerged sand has proved to be much more efficient & effective

And a previous project done at Calafell (50km south) beach will work at Castelldefels.

Efficient storm water retention basins

Beautiful landscapes

Biodiversity

There’s a big chance for a management plan of the emerged sand budget, combining precise LIDAR information, dune construction, beach profile reconstruction and coastal lagoon excavation

A nature-based solution for coastal defence and climate change adaptation.

An evidence-based management plan that includes a strong social component

We are modelling scenarios for RCP 2.6 (57cm SLR and 25 m of beach regression, yr 2.100) for the different factors: wahsover risk, erosion, flood events,...

But adapting fast to much more near ones! (this is Emilia Romagna on Italy last year)

A nature-based solution to get resilient beaches

With reliable data from LIDAR yearly flights

http://maps.croma.org.es/geoserver/www/cr004_visor-ampliat.html

With a Web Map service

Nature-based solution involving policy analysis, governance, and participated coastal engineering

lascurain@sgm.es@volemduneshttp://www.operas-project.eu/