Long-Distance Interactions Regulate the Structure and Resilience of Coastal Ecosystems

Abstract

Mounting evidence indicates that spatial interactions are important in structuring coastal ecosystems. Until recently, however, most of this work has been focused on seemingly exceptional systems that are characterized by regular, self-organized patterns. In this review, we document that interactions that operate at long distances, beyond the direct neighborhood of individual organisms, are more common and have much more far-reaching implications for coastal ecosystems than was previously realized. We review studies from a variety of ecosystem types-including cobble beaches, mussel beds, coral reefs, seagrass meadows, and mangrove forests-that reveal a startling interplay of positive and negative interactions between habitats across distances of up to a kilometer. In addition to classical feeding relations, alterations of physical conditions constitute an important part of these long-distance interactions. This entanglement of habitats has crucial implications for how humans manage coastal ecosystems, and evaluations of anthropogenic impact should explicitly address long-distance and system-wide effects before we deem these human activities to be causing little harm.

How habitat-modifying organisms structure the food web of two coastal ecosystems

“…Studies from a wide range of ecosystems have shown that amelioration of physical stress by habitat-modifying organisms can profoundly impact the associated community by facilitating other species [16], and recent work demonstrated that this effect may not only be local [41]. On cobble beaches, for instance, many studies (including this one) have revealed non-trophic facilitation of the local community [23,42] and that at a scale of metres to tens of metres, cordgrass patches function as wave breaks to facilitate wave-sensitive forb species [43].…”

Opportunities for Protecting and Restoring Tropical Coastal Ecosystems by Utilizing a Physical Connectivity Approach

“…We are aware local effects can extend beyond the ecosystem and its ecosystem engineers to affect other types of ecosystems this can be positive (sediment buffering in turbid waters) or negative (nutrient retention in oligotrophic areas; Sheaves, 2009). Here, we concentrate only on how local physical modification of the abiotic environment can have extended spatial influence on flux exchanges among different ecosystems within landscapes and seascapes (Gillis et al, 2014a;Koppel et al, 2015). In tropical coastal seascapes, the physical structure of "donor" ecosystems can affect the establishment and persistence of "recipient" ecosystems positively, including the engineering FIGURE 2 | The left hand side panel 1, representatives tropical coastal seascape showing a mangrove forest, a seagrass bed, and a coral reef; energetic and material exchanges among them; and illustrative monitoring technologies (A-E).…”

“…If all three types of ecosystems are both donors and recipients, when they are sufficiently proximate, concentrating on one ecosystem as a single unit risks management failure especially when interconnections influence ecosystem functioning (Lovett et al, 2005;Koppel et al, 2015;Guannel et al, 2016). In such cases, a seascape approach to management is needed.…”

“…Research in tropical coastal seascapes has revealed ecosystem engineering species within some ecosystems (i.e., species that physically modify the abiotic environment Jones et al, 1994) can significantly reduce wave energy from the ocean to the land and reduce nutrient and sediment fluxes from the land to the ocean (Gillis et al, 2014a;Saunders et al, 2014;Koppel et al, 2015;Guannel et al, 2016). Effects can occur over distances sufficient to encompass and positively affect other ecosystem types lying within the energetic and material flux paths from ocean to land and vice versa (Gillis et al, 2014a;Saunders et al, 2014;Koppel et al, 2015;Guannel et al, 2016). In this perspective, we will argue that new technologies and knowledge can link together to provide the foundations for innovative inter-ecosystem connectivity management (monitoring and restoration).…”

The use of remote sensing to reveal landscape-scale ecosystem engineering by shellfish reefs

“…The ability of organisms to modify the abiotic environment is commonly referred to as ecosystem engineering (Jones et al 1997;sensu Jones et al 1994). In coastal environments, ecosystem engineers are able to mediate resources and/or alter the physical state of the system locally, but also beyond the borders of the zone that is physically occupied (for an overview see van de Koppel et al 2015;Donadi, Westra, et al 2013;van der Zee et al 2012;Gillis et al 2014;Engel et al 2017;van de Koppel et al 2006). This is often referred to as spatially extended ecosystem engineering.…”