Prof. Dr. Ir. Tjisse van der Heide

Tjisse van der Heide, professor of Coastal Ecology, studies ecological interactions along the entire elevational gradient of soft-sediment coasts: from coastal dunes, salt marshes and intertidal mudflat all the way down into the subtidal which never emerges during low tide. ‘These shallow coastal areas are important, because they protect our coasts, serve as drinking water sources, and support many different plant and animal species. In contrast to rocky shores, that are characterized by steep gradients from high to low, healthy soft-sediment coasts typically have long elevational gradients supporting a diverse mosaic of coastal habitats. However, as a consequence of coastal development on one side and sea level rise on the other, humans have restricted these long gradients into a progressively narrowing coastal strip – a process called the ‘coastal squeeze’. This is resulting in great loss of coastal habitat and the functions and services they provide’

Ecosystem engineers

Within these coastal zones, my work primarily focuses on how habitat-modifying species, often called ‘ecosystem engineers’ or ‘foundation species’, shape coastal landscapes. In coastal dunes, for instance, I aim to understand how clonally growing grasses accumulate sand to build dunes, allowing them to escape stress from flooding by seawater. On intertidal flat and in the subtidal, I study seagrasses and mussels that form large beds that attenuate waves and accumulate sediment particles, thereby building a landscape that not only benefits the engineering species, but also a biodiverse associated community.

Conserving and restoring ecosystem services

Ecosystem engineers are not only important from an ecological perspective, given that humans are definitely amongst the many species that profit from the landscapes they build. Coastal ecosystem engineers provide important ‘ecosystem services’. Their landscapes, for instance, offer protection against flooding during storms, decreasing the impact on man-made defences such as dikes, while simultaneously serving as carbon sinks, and as foraging and nursery areas for commercially important species. Because of their great ecological and societal relevance, we are therefore not only trying to elucidate how they function, but also figure out how we can restore lost or degraded ecosystems. To achieve this, we are developing biodegradable establishment structures that temporarily mimic the landscape modifying traits of ecosystem engineers, allowing the actual species to establish and take over as the structures naturally degrade’.