Keynotes

Past, present and future of sandy beach ecology

Past, present and future of sandy beach ecology

Speaker: Prof. Omar Defeo

Unidad de Ciencias del Mar, Universidad de la Republica, Uruguay

Sandy beach research began intermittently about a century ago, only broadening in the second half of the 20th century and always lagging behind attention given to other coastal ecosystem types. While still behind other coastal habitats in annual research output, beaches have been receiving much greater attention in recent decades, especially since the initiation of a series of international symposia on the ecology of these systems. The first international sandy beach symposium, held in Port Elizabeth, South Africa in 1983, was a milestone and established modern sandy beach research as a recognized discipline in coastal ecology. Main emphasis was placed on the underlying physical structure and basic ecological processes that define and control the beach system, through the uniquely adapted fauna and flora, to the ecosystem structure. For the first time, sandy beaches were seen as ecosystems, and this foundation was built upon by seven further meetings, which were held in Chile, Italy, Spain, Morocco, South Africa, Brazil, and Crete. As time goes by, researchers have delved deeply into elucidating the intricate interactions among organisms inhabiting sandy shores, shedding light on their biodiversity, ecological processes, and responses to environmental changes. Further, despite sandy beaches being seen as intertidal interfaces between sea and land, a wider perspective was taken, seeing the beach as tightly coupled to its adjacent dunes and surf zone, which together defines the holistic littoral active zone. Through innovative methodologies and technologies, such as remote sensing, molecular analysis, and ecological modelling, scientists have gained insights into the complex dynamics of these ecosystems. Beach science has now developed beyond the initial exploratory stage and is an established and expanding field, based on paradigms, concepts and ideas of ecosystem structure.

Research has evolved and humans become an ever more central part of the social-ecological system that is the sandy beach. Studies have increasingly focused on the impacts of human activities on sandy shore ecosystems, as well as the services that healthy, functional beaches provide to societies. Our understanding of the challenges facing sandy coasts, amidst the compounded impacts of natural and anthropogenic perturbations, requires holistic approaches to keep expanding our knowledge base. The inevitable reality of the significant human footprint on sandy shores highlights the need for collective action as the foundation for participatory governance.

Despite progress, numerous questions remain unanswered, offering ample opportunity for further understanding and improved management of these invaluable ecosystems.

Speaker: Prof. Omar Defeo

Unidad de Ciencias del Mar, Universidad de la Republica, Uruguay

Sandy beach research began intermittently about a century ago, only broadening in the second half of the 20th century and always lagging behind attention given to other coastal ecosystem types. While still behind other coastal habitats in annual research output, beaches have been receiving much greater attention in recent decades, especially since the initiation of a series of international symposia on the ecology of these systems. The first international sandy beach symposium, held in Port Elizabeth, South Africa in 1983, was a milestone and established modern sandy beach research as a recognized discipline in coastal ecology. Main emphasis was placed on the underlying physical structure and basic ecological processes that define and control the beach system, through the uniquely adapted fauna and flora, to the ecosystem structure. For the first time, sandy beaches were seen as ecosystems, and this foundation was built upon by seven further meetings, which were held in Chile, Italy, Spain, Morocco, South Africa, Brazil, and Crete. As time goes by, researchers have delved deeply into elucidating the intricate interactions among organisms inhabiting sandy shores, shedding light on their biodiversity, ecological processes, and responses to environmental changes. Further, despite sandy beaches being seen as intertidal interfaces between sea and land, a wider perspective was taken, seeing the beach as tightly coupled to its adjacent dunes and surf zone, which together defines the holistic littoral active zone. Through innovative methodologies and technologies, such as remote sensing, molecular analysis, and ecological modelling, scientists have gained insights into the complex dynamics of these ecosystems. Beach science has now developed beyond the initial exploratory stage and is an established and expanding field, based on paradigms, concepts and ideas of ecosystem structure.

Research has evolved and humans become an ever more central part of the social-ecological system that is the sandy beach. Studies have increasingly focused on the impacts of human activities on sandy shore ecosystems, as well as the services that healthy, functional beaches provide to societies. Our understanding of the challenges facing sandy coasts, amidst the compounded impacts of natural and anthropogenic perturbations, requires holistic approaches to keep expanding our knowledge base. The inevitable reality of the significant human footprint on sandy shores highlights the need for collective action as the foundation for participatory governance.

Despite progress, numerous questions remain unanswered, offering ample opportunity for further understanding and improved management of these invaluable ecosystems.

Connectivity between sandy beaches:
The challenges of creating a network of Marine Protected Areas

Connectivity between sandy beaches:
The challenges of creating a network of Marine Protected Areas

Speaker: Prof. John M Baxter

Unidad de Ciencias del Mar, Universidad de la Republica, Uruguay

As the number of designated Marine Protected Areas (MPAs) in the world increases, many countries claim to have created MPA networks to meet their 30 x 30 commitments. The IUCN defines an MPA network as ‘A collection of individual MPAs operating cooperatively and synergistically at various spatial scales and with a range of protection levels that are designed to meet objectives that a single reserve cannot achieve’. In reality, most ‘so called’ networks of MPAs are at best collections of MPAs each having been selected for their individual features, and any actual connectivity between sites is coincidental and at best incomplete. The various aspects of connectivity, including passive connectivity, active connectivity, and habitat and seascape scale connectivity will be discussed. The complexity of the issues that need to be taken into account when designing a truly connected network of protected areas will be explored using the example of horse mussel beds in Scotland. Although not a sandy beach species the lessons learned from investigating this species are relevant to ensuring that what is created is a connected network of sandy shore sites. No measure of connectivity between sites is absolute – different species’ dispersal mechanisms and ranges exist. What may represent the optimal connectivity between various sites for one species may be totally inadequate for another. Thus, any claims of connectivity need to be clearly defined.

To establish connectivity within a network of MPAs there needs to be better understanding of how connections between sites operate in both time and space, as well as greater recognition of the impacts of present and future climate change together with the importance of identifying and protecting refugia for given species, better monitoring to demonstrate continuing or new connectivity. Finally, it is important to establish what level of certainty in the effectiveness of any connectivity is acceptable and whether it can be determined by inference rather than more labour-intensive procedures such as genetics studies or tagging.

Speaker: Prof. John M Baxter

Unidad de Ciencias del Mar, Universidad de la Republica, Uruguay

As the number of designated Marine Protected Areas (MPAs) in the world increases, many countries claim to have created MPA networks to meet their 30 x 30 commitments. The IUCN defines an MPA network as ‘A collection of individual MPAs operating cooperatively and synergistically at various spatial scales and with a range of protection levels that are designed to meet objectives that a single reserve cannot achieve’. In reality, most ‘so called’ networks of MPAs are at best collections of MPAs each having been selected for their individual features, and any actual connectivity between sites is coincidental and at best incomplete. The various aspects of connectivity, including passive connectivity, active connectivity, and habitat and seascape scale connectivity will be discussed. The complexity of the issues that need to be taken into account when designing a truly connected network of protected areas will be explored using the example of horse mussel beds in Scotland. Although not a sandy beach species the lessons learned from investigating this species are relevant to ensuring that what is created is a connected network of sandy shore sites. No measure of connectivity between sites is absolute – different species’ dispersal mechanisms and ranges exist. What may represent the optimal connectivity between various sites for one species may be totally inadequate for another. Thus, any claims of connectivity need to be clearly defined.

To establish connectivity within a network of MPAs there needs to be better understanding of how connections between sites operate in both time and space, as well as greater recognition of the impacts of present and future climate change together with the importance of identifying and protecting refugia for given species, better monitoring to demonstrate continuing or new connectivity. Finally, it is important to establish what level of certainty in the effectiveness of any connectivity is acceptable and whether it can be determined by inference rather than more labour-intensive procedures such as genetics studies or tagging.

Collapse disasters at/around natural and artificial sandy beaches with mitigation measures

Collapse disasters at/around natural and artificial sandy beaches with mitigation measures

Speaker: Dr. Shinji Sassa

Chair of the International Technical Committee on Scour and Erosion
National Institute of Maritime, Port and Aviation Technology, Japan


Amid global climate change, the ocean wave conditions are becoming more severe along more than half of the world’s coasts, posing risks of coastal disasters worldwide. Here, I present some recent advances in understanding and mitigating the impact of collapse disasters at/around natural and artificial sandy beaches. Collapse is a consequence of coastal internal erosion, cavity formation and cavity destabilization under diverse environmental forcing such as waves, tides, flows, groundwater level fluctuations, rainfalls, and earthquakes. Collapse can lead to a fatal accident where a cavity formed in sands suddenly collapses without giving any alarming signs to the sand surface. The key factors and processes involved are: propagation of fluctuating water pressure, wash out of sand particles, arch effect and the role of suction. The role of suction, i.e. negative pore water pressure relative to atmospheric pressure, is of particular importance, since no significant cavities would be formed in dry or saturated states of sands. This means that suction may control the lifetime of cavities in unsaturated granular materials above groundwater levels accompanying flows of pore fluids (air and water) under complex hydro-environmental conditions. In an artificial sandy beach, internal erosion stems from defects in joints or sand covers of coastal facilities, allowing sand particles to be washed out through the joints and/or defects under continued hydrodynamic forcing such as waves and tides. Cavity collapses when suction decreases irrespective of the types of forcing conditions. A practical countermeasure for suppressing such internal erosion and collapse in artificial sandy beaches has been developed for disaster prevention/mitigation. Severe wave impacts can occasionally cause damages to coastal roads surrounding natural sandy beaches owing to scour and erosion. The combined analyses of wind waves, hydraulic flume experiments, and field surveys of the past coastal disasters demonstrate that the collapses of the coastal road embankment slopes behind natural sandy beaches are the consequence of coupled surface erosion, scour, and internal erosion subject to waves, flows, and overtopping. The presence of overtopping enlarges the extent of collapses. New filter design criteria can facilitate preventing and mitigating the impact of such collapse disasters against various dynamic forcing conditions.

Speaker: Dr. Shinji Sassa

Chair of the International Technical Committee on Scour and Erosion
National Institute of Maritime, Port and Aviation Technology, Japan


Amid global climate change, the ocean wave conditions are becoming more severe along more than half of the world’s coasts, posing risks of coastal disasters worldwide. Here, I present some recent advances in understanding and mitigating the impact of collapse disasters at/around natural and artificial sandy beaches. Collapse is a consequence of coastal internal erosion, cavity formation and cavity destabilization under diverse environmental forcing such as waves, tides, flows, groundwater level fluctuations, rainfalls, and earthquakes. Collapse can lead to a fatal accident where a cavity formed in sands suddenly collapses without giving any alarming signs to the sand surface. The key factors and processes involved are: propagation of fluctuating water pressure, wash out of sand particles, arch effect and the role of suction. The role of suction, i.e. negative pore water pressure relative to atmospheric pressure, is of particular importance, since no significant cavities would be formed in dry or saturated states of sands. This means that suction may control the lifetime of cavities in unsaturated granular materials above groundwater levels accompanying flows of pore fluids (air and water) under complex hydro-environmental conditions. In an artificial sandy beach, internal erosion stems from defects in joints or sand covers of coastal facilities, allowing sand particles to be washed out through the joints and/or defects under continued hydrodynamic forcing such as waves and tides. Cavity collapses when suction decreases irrespective of the types of forcing conditions. A practical countermeasure for suppressing such internal erosion and collapse in artificial sandy beaches has been developed for disaster prevention/mitigation. Severe wave impacts can occasionally cause damages to coastal roads surrounding natural sandy beaches owing to scour and erosion. The combined analyses of wind waves, hydraulic flume experiments, and field surveys of the past coastal disasters demonstrate that the collapses of the coastal road embankment slopes behind natural sandy beaches are the consequence of coupled surface erosion, scour, and internal erosion subject to waves, flows, and overtopping. The presence of overtopping enlarges the extent of collapses. New filter design criteria can facilitate preventing and mitigating the impact of such collapse disasters against various dynamic forcing conditions.