Keywords :

TROPHIC CASCADE – A trophic cascade occurs when a change at one level of the food web (often due to the addition or removal of a keystone species) causes a series of indirect effects on lower trophic levels. This can lead to significant and widespread changes in ecosystem structure and nutrient cycling.

KEYSTONE SPECIES – A species which has a disproportionately large impact on their environment relative to their abundance. The removal or addition of a keystone species can initiate a trophic cascade.


At the end of the last century, Barcelona needed an extension of the maritime line to link the city with new beaches. On May 25, 1999, Mayor Joan Clos initiated the Parque Diagonal Mar project, designed by Enric Miralles and Benedetta Tagliabue. Inspired by rain-soaked visit, Miralles envisioned a marshland.


Current Species At Site

Keystone Species : Audouin’s Gull

Audouin’s gull, a rare species which once used to be a frequent visitor to the site, can serve as an indicator species that signify a successfully thriving ecosystem in the park.

Audouin’s gull (Larus audouinii) is a medium-sized Mediterranean gull with a distinctive red-tipped bill. It has rebounded from near-threatened status. However, it faces ongoing threats from habitat loss, human disturbance, invasive species predation, and overfishing. Coastal development, tourism, and climate change further disrupt nesting sites and food sources, challenging their conservation and population stability.

Proposal :

Transforming a concrete lake into a self-sustaining brackish water wetland could alleviate issues of Eutrophication and biodiversity depletion. The close vicinity to sea provides the opportunity to dig into the ground to let the sea water seep in and fill the waterbody basin, creating a brackish water ecosystem.

Establishing a self-regulating ecosystem where each organism plays a crucial role in ensuring the survival of the other organisms which is monitored by modern tools and technologies. The pioneer species are the Mallards, Greylag Geese and Yellow-legged Seagulls. The arrival of the keystone species i.e., the Audouin’s Gull is the signal for a healthy & thriving ecosystem.

Monitoring Technologies and Tools:


The Water Level Sensors and Salinity Sensors indicate the requirement to open the Single way valve to let in salt water from sea to the waterbody basin. The Nitrite tester will give information about the amount of population of new species to be introduced into the system to create a healthy Trophic Cascade. Introduction of the Common Reed, Duckweed, Spanish Toothcarps and Grey Mullets will control eutrophication and provide food for the Mallards and Greylag Geese.

The onset of arrival of the Keystone Species, which is the Audouin’s Gull will be notified through Mobile Applications by Nature Enthusiasts and Bird Watchers around the site. Additionally this would be informed through Sound Detection and Identification microphones installed on site. This in-turn gives signal to release Drones equipped with cameras to get the number of Audouin’s Gulls present at site. Furthermore, DNA sampling machines installed in the water body can detect the amount of time Audouin’s Gulls spend at the site, through Metagenomic Analysis of the bird excrement samples present in the water body.