We provide a brief synopsis of the unique physical and ecological attributes of sandy beach ecosystems and review the main anthropogenic pressures acting on the world's single largest type of open shoreline. Threats to beaches arise from a range of stressors which span a spectrum of impact scales from localised effects (e.g. trampling) to a truly global reach (e.g. sea-level rise). These pressures act at multiple temporal and spatial scales, translating into ecological impacts that are manifested across several dimensions in time and space so that today almost every beach on every coastline is threatened by human activities. Press disturbances (whatever the impact source involved) are becoming increasingly common, operating on time scales of years to decades. However, long-term data sets that describe either the natural dynamics of beach systems or the human impacts on beaches are scarce and fragmentary. A top priority is to implement long-term field experiments and monitoring programmes that quantify the dynamics of key ecological attributes on sandy beaches. Because of the inertia associated with global climate change and human population growth, no realistic management scenario will alleviate these threats in the short term. The immediate priority is to avoid further development of coastal areas likely to be directly impacted by retreating shorelines. There is also scope for improvement in experimental design to better distinguish natural variability from anthropogenic impacts. Sea-level rise and other effects of global warming are expected to intensify other anthropogenic pressures, and could cause unprecedented ecological impacts. The definition of the relevant scales of analysis, which will vary according to the magnitude of the impact and the organisational level under analysis, and the recognition of a physical–biological coupling at different scales, should be included in approaches to quantify impacts. Zoning strategies and marine reserves, which have not been widely implemented in sandy beaches, could be a key tool for biodiversity conservation and should also facilitate spillover effects into adjacent beach habitats. Setback and zoning strategies need to be enforced through legislation, and all relevant stakeholders should be included in the design, implementation and institutionalisation of these initiatives. New perspectives for rational management of sandy beaches require paradigm shifts, by including not only basic ecosystem principles, but also incentives for effective governance and sharing of management roles between government and local stakeholders.

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Threats to sandy beach ecosystems: A review

This text details animal orientation with the help of information from the geomagnetic field. It reviews the magnetic effects on spatial behaviour in the various groups of the animal kingdom from platyhelminths to vertebrates, with an emphasis on birds as the best studied group. The discussion covers "compass" and "non-compass" effects and different types of responses, for example, alignments, compass orientation and orientation by the spatial distribution of magnetic parameters, which should aid the reader's understanding of the various ways magnetic information may be used.

Magnetic orientation in animals

Ichnology is the study of traces created in the substrate by living organisms. This is the first book to systematically cover basic concepts and applications in both paleobiology and sedimentology, bridging the gap between the two main facets of the field. It emphasizes the importance of understanding ecologic controls on benthic fauna distribution and the role of burrowing organisms in changing their environments. A detailed analysis of the ichnology of a range of depositional environments is presented using examples from the Precambrian to the recent, and the use of trace fossils in facies analysis and sequence stratigraphy is discussed. The potential for biogenic structures to provide valuable information and solve problems in a wide range of fields is also highlighted. An invaluable resource for researchers and graduate students in paleontology, sedimentology and sequence stratigraphy, this book will also be of interest to industry professionals working in petroleum geoscience.

Ichnology: Organism-Substrate Interactions in Space and Time

To investigate the influence of marine macrophyte wrack subsidies on community structure, relationships between community attributes, including species richness, abundance, and biomass of macrofauna and abundance of shorebirds, and a variety of factors, including the standing crop of wrack and beach morphodynamics, were examined on 15 exposed sandy beaches on the southern California coast. The beaches sampled were primarily modally intermediate morphodynamic types, and three were groomed regularly. Species richness, abundance, and biomass of the macrofauna were high compared to values reported for similar beach types in other regions and were not predicted by morphodynamics or other physical factors. Overall species richness and abundance, and the species richness, abundance, and biomass of wrack-associated fauna and selected taxa were significantly correlated with the standing crop of macrophyte wrack. Wrack-associated macrofauna, such as amphipods, isopods, and insects, made up an average of >37% of the species on ungroomed beaches and comprised 25% or more of the total abundance on half of those beaches. The abundance of two shorebird species, plovers that forage using visual cues, was positively correlated with the standing crop of wrack and with the abundance of wrack-associated invertebrates. Significant differences in community structure, including depressed species richness, abundance, and biomass of macrofauna, especially for wrack-associated taxa, were associated with beach grooming and provided strong evidence for the bottom-up effects of wrack subsidies. Grooming also reduced the prey available to vertebrate predators, such as shorebirds. Substantial ecological effects of the large-scale disturbance and removal of organic material, food resources, and habitat are associated with beach grooming. These results suggest that macrophyte wrack subsidies strongly influence macrofaunal community structure, higher trophic levels, and ecological processes on exposed sandy beaches. The supply of macrophyte wrack should be considered as a factor in ecological studies of exposed sandy beaches, particularly where macrophyte production is high.

The response of macrofauna communities and shorebirds to macrophyte wrack subsidies on exposed sandy beaches of southern California

Physical and biological factors govern com- munity and population features of sandy beach macro- fauna. At the macroscale, species richness decreases from tropical to temperate beaches, and from macrotidal dissipative to microtidal reflective beaches. At the species level, life history traits are highly plastic over latitudinal gradients; large-scale variations in environmental vari- ables modulate intraspecific phenotypic differentiation. At the mesoscale, alongshore and across-shore distribu- tions tend to be unimodal, bell-shaped within a beach, with abundance varying from the central region to the boundaries, even though environmental gradients (wave exposure, salinity) can cause asymmetries. Zona- tion is highly dynamic and not sharply defined. This is attributed to short- (hourly, daily) or medium- (seasonal) term reactions to environmental conditions, passive transport and sorting by the swash (e.g. recruits), active micro-habitat selection (e.g. adults), and intra- and inter- specific interactions. Across-shore distribution may be- come multimodal due to intraspecific segregation by sizes during recruitment. At the microscale (individual neighbourhood or quadrat scale), behavioural factors and intra-/interspecific interactions become more important as density increases. Human induced impacts also gener- ate variability in population demography, structure and dynamics. We identify physical-biological coupling at dif- ferent temporal and spatial scales, emphasizing the role of life history traits in order to assess alternative regula- tory mechanisms and processes. Our synthesis suggests that: (1) biological interactions are more important regu- latory agents than previously thought: in benign dissipa- tive beaches or undisturbed sites, intra- and interspecific competition can be more intense than in reflective beach- es or disturbed sites, where the populations are physi- cally controlled; (2) supralittoral forms are relatively inde- pendent of the swash regime and show no clear response to beach type; (3) marked long-term fluctuations are noticeable in species with planktonic larvae structured as metapopulations, due to environmental disturbances and stochasticity in reproduction and recruitment.

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Patterns, processes and regulatory mechanisms in sandy beach macrofauna: a multi-scale analysis

1. Introduction 2. The Physical Environment 3. The Interstitial Environment 4. Beach and Surf Zone Flora 5. Sandy Beach Invertebrates 6. Adaptation to Sandy Beach Life 7. Benthic Macrofauna Communities 8. Benthic Macrofauna Populations 9. Interstitial Ecology 10. Surf Zone Fauna 11. Turtles and Terrestrial Vertebrates 12. Energetics and Nutrient Cycling 13. Coastal Dune Ecosystems and Dune-beach Interactions 13. Conclusions 14. Human Impacts 15. Coastal Zone Management 16. Glossary 17. References 18. Appendices

The ecology of sandy shores

1. Introduction. 2. The Physical Environment. Sand. Porosity and permeability. Penetrability. Waves. Types of waves. Wave energy. Refraction. Shoaling and breaking. Wave-driven longshore currents and rip currents. Bound and infragravity waves - surf beat. Edge waves. Tides. Internal waves. Wind. Sand movement. Interaction between beach slope, waves and particle size. Beach types. Circulation cells and mixing. Water filtration by the sand. Exposure rating. Conclusion. 3. Beach and Surf-zone Flora. Benthic microflora. Surf-zone phytoplankton. Conclusions. 4. Sandy-beach Invertebrates, with special reference to the Macrofaunal Genera. Phylum:Porifera. Phylum:Cnidaria. Phylum:Platyhelminths. Phylum:Nemertea. Phylum:Nematoda. Phylum:Rotifera. Phylum:Gastrotricha. Phylum:Kinorhyncha. Phylum:Loricifera. Phylum:Annelida. Phylum:Echiurida. Phylum:Sipunculoidea. Phylum:Brachiopoda. Phylum:Mollusca. Phylum:Tardigrada. Phylum:Arthropoda. Phylum:Ectoprocta. Phylum:Echinodermata. Phylum:Hemichordata. 5. Adaptations to Sandy-beach Life. Locomotion:burrowing. Locomotion:surfing. Rhythms of activity. Sensory responses and orientation. Choice of habitat. Nutrition. Respiration. Environmental tolerances. Reproduction. Aggregations and gregariousness. Responses to and avoidance of predators. Conclusions. 6. The Macrobenthic Communities. Sampling methods. Diversity and abundance. Distribution and zonation. Migrations and spatial and temporal changes. Competition, disturbance and predation. Trophic relationships. Conclusions. 7. Interstitial Ecology. The interstitial climate. The biota. Distribution of the interstitial fauna. Temporal changes. Meiofaunal communities. Trophic relationships. Biological interactions. Conclusions. 8. Surf-zone Fauna. Zooplankton:composition. Adaptations of surf-zone zooplankton. Zooplankton:migrations. Zooplankton:distribution. Zooplankton:biomass and abundance. Food and feeding relationships. Surf-zone fishes. Juveniles and nursery areas. Surf-zone fish communities. Fishes:temporal variability. Ichthyofaunal trophic relationships. Other groups. Conclusions. 9. Birds and other Terrestrial Vertebrates. 10. Sandy Beach Ecosystems. Food sources. Macroscopic food chains. Examples of macroscopic food chains. The interstitial food chain. The microbial loop. Energy flow in beach and surf-zone ecosystems. The sandy beaches of the Eastern Cape. Nutrient cycling. Conclusions. 11. Sandy Beaches and Pollution. Crude oil pollution. Oil dispersants. Sewage and organic enrichment. Factory effluents. Thermal pollution. Indicators of pollution. Toxicity studies. Conclusions. 12. The Dune Ecosystem and Dune/Beach Exchanges. The physical environment - wind and sand transport. Coastal dune formation by vegetation. Dune types. Edaphic features. Water. The gradient across coastal dunefields. Dune vegetation. The fauna. Food chains of the dune ecosystem. Dune/beach exchanges. A case study of dune/beach exchanges. Conclusions. 13. Conservation and Management.

Ecology of Sandy Shores

Aquatic Ecosystems: Sandy shores of the near future

Sandy shores of the near future

This chapter introduces the general features of sandy beaches. Sandy coastlines are dynamic environments where the physical structure of the marine habitat is determined by the interaction among sand, waves, and tides. Sandy beaches constitute one of the most resilient types of dynamic coastline because of their ability to absorb wave energy. This wave energy is expended in driving surf-zone water movement, which carries sand offshore during storms and moves it back onshore during calms. The beach is characterized by wave-driven sand transport and by eolian (wind) transport in the backshore and dunes. Most beaches are backed by dunes and interact with them in terms of sediment budgets by either supplying or receiving sand. This sediment transport, in the surf zone by wave action and in the dunes by wind action, has both a shore normal and a longshore component. On many coasts, longshore transport accounts for vast volumes of sand. The sandy beach is thus an extremely dynamic environment where sand and water are always in motion.

A. C. Brown

Papers

The ecology of sandy shores

Ecology of Sandy Shores

Aquatic Ecosystems: Sandy shores of the near future

Sandy shores of the near future

2 – The Physical Environment