Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

Beginning with Emlen (1966) and MacArthur and Pianka (1966) and extending through the last ten years, several authors have sought to predict the foraging behavior of animals by means of mathematical models. These models are very similar,in that they all assume that the fitness of a foraging animal is a function of the efficiency of foraging measured in terms of some "currency" (Schoener, 1971) -usually energy- and that natural selection has resulted in animals that forage so as to maximize this fitness. As a result of these similarities, the models have become known as "optimal foraging models"; and the theory that embodies them, "optimal foraging theory." The situations to which optimal foraging theory has been applied, with the exception of a few recent studies, can be divided into the following four categories: (1) choice by an animal of which food types to eat (i.e., optimal diet); (2) choice of which patch type to feed in (i.e., optimal patch choice); (3) optimal allocation of time to different patches; and (4) optimal patterns and speed of movements. In this review we discuss each of these categories separately, dealing with both the theoretical developments and the data that permit tests of the predictions. The review is selective in the sense that we emphasize studies that either develop testable predictions or that attempt to test predictions in a precise quantitative manner. We also discuss what we see to be some of the future developments in the area of optimal foraging theory and how this theory can be related to other areas of biology. Our general conclusion is that the simple models so far formulated are supported are supported reasonably well by available data and that we are optimistic about the value both now and in the future of optimal foraging theory. We argue, however, that these simple models will requre much modification, espicially to deal with situations that either cannot easily be put into one or another of the above four categories or entail currencies more complicated that just energy.

Citation classic - optimal foraging - a selective review of theory and tests

The boundary layer equations for plane, incompressible, and steady flow are 

$$\matrix{ {u{{\partial u} \over {\partial x}} + v{{\partial u} \over {\partial y}} = - {1 \over \varrho }{{\partial p} \over {\partial x}} + v{{{\partial ^2}u} \over {\partial {y^2}}},} \cr {0 = {{\partial p} \over {\partial y}},} \cr {{{\partial u} \over {\partial x}} + {{\partial v} \over {\partial y}} = 0.} \cr }$$

Boundary Layer Theory

Connectivity, or the exchange of individuals among marine populations, is a central topic in marine ecology. For most benthic marine species with complex life cycles, this exchange occurs primarily during the pelagic larval stage. The small size of larvae coupled with the vast and complex fluid environment they occupy hamper our ability to quantify dispersal and connectivity. Evidence from direct and indirect approaches using geochemical and genetic techniques suggests that populations range from fully open to fully closed. Understanding the biophysical processes that contribute to observed dispersal patterns requires integrated interdisciplinary approaches that incorporate high-resolution biophysical modeling and empirical data. Further, differential postsettlement survival of larvae may add complexity to measurements of connectivity. The degree to which populations self recruit or receive subsidy from other populations has consequences for a number of fundamental ecological processes that affect population regulation and persistence. Finally, a full understanding of population connectivity has important applications for management and conservation.

Larval Dispersal and Marine Population Connectivity

What determines the number and size of the seeds produced by a plant? How often should it reproduce them? How often should a plant produce them? Why and how are seeds dispersed, and what are the implications for the diversity and composition of vegetation? These are just some of the questions tackled in this wide-ranging review of the role of seeds in the ecology of plants. The authors bring together information on the ecological aspects of seed biology, starting with a consideration of reproductive strategies in seed plants and progressing through the life cycle, covering seed maturation, dispersal, storage in the soil, dormancy, germination, seedling establishment, and regeneration in the field. The text encompasses a wide range of concepts of general relevance to plant ecology, reflecting the central role that the study of seed ecology has played in elucidating many fundamental aspects of plant community function.

The ecology of seeds

Native oyster reefs once dominated many estuaries, ecologically and economically. Centuries of resource extraction exacerbated by coastal degradation have pushed oyster reefs to the brink of functional extinction worldwide. We examined the condition of oyster reefs across 144 bays and 44 ecoregions; our comparisons of past with present abundances indicate that more than 90% of them have been lost in bays (70%) and ecoregions (63%). In many bays, more than 99% of oyster reefs have been lost and are functionally extinct. Overall, we estimate that 85% of oyster reefs have been lost globally. Most of the world's remaining wild capture of native oysters (> 75%) comes from just five ecoregions in North America, yet the condition of reefs in these ecoregions is poor at best, except in the Gulf of Mexico. We identify many cost-effective solutions for conservation, restoration, and the management of fisheries and nonnative species that could reverse these oyster losses and restore reef ecosystem services.

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Oyster Reefs at Risk and Recommendations for Conservation, Restoration, and Management

The importance of restoring filter-feeders, such as the Eastern oyster Crassostrea virginica, to mitigate the effects of eutrophication (e.g. in Chesapeake Bay) is currently under debate. The argument that bivalve molluscs alone cannot control phytoplankton blooms and reduce hypoxia oversimplifies a more complex issue, namely that ecosystem engineering species make manifold contributions to ecosystem services. Although further discussion and research leading to a more complete understanding is required, oysters and other molluscs (e.g. mussels) in estuarine eco- systems provide services far beyond the mere top-down control of phytoplankton blooms, such as (1) seston filtration, (2) benthic-pelagic coupling, (3) creation of refugia from predation, (4) creation of feeding habitat for juveniles and adults of mobile species, and for sessile stages of species that attach to molluscan shells, and (5) provision of nesting habitat.

/pdf/ecosystem-services-related-to-oyster-restoration-2s5ki3syld.pdf

Ecosystem services related to oyster restoration

Developing success criteria and goals for evaluating oyster reef restoration: Ecological function or resource exploitation?

Seagrasses rely on both vegetative (rhizome elongation) and sexual (seeds) propagation for maintenance of existing beds and colonization of new areas. Yet mecha- nisms of seed dispersal and survival of seeds in new areas remain poorly described. We conducted seed dispersal experiments in the field and laboratory to better describe seed dispersal characteristics in one species, Zostera marina L. (eelgrass), the dominant seagrass species in the temperate zone of the United States, Japan, and Europe. Seeds were broadcast by hand into unvegetated 5 m diameter plots at three locations over 3 yr (1989-1991) in the York River, Virginia (Chesapeake Bay). These sites had been previously vegetated but were devoid of any vegetation prior to (since 1972) and during the course of the experiments. Resultant seedling distributions closely matched broadcast patterns, with 80% of all seedlings found within the 5 m diameter plots, despite the fact that geophysical processes would appear sufficient to transport seeds greater distances. Wind records for the 2-mo period between seed broadcasting and germination revealed time-averaged wind speeds in excess of 40 km/h on 12 d in each of the 3 yr and gale- force winds (72 km/h) in 2 of 3 yr. A three-dimensional hydrographic computer simulation model of the York River provided instantaneous current velocity estimates from which maximum bottom shear velocities (u.) in the study area were approximated (flood tide: 1.26 cm/s, ebb tide: 1.20 cm/s). These estimates exceeded the critical erosion threshold (ucrit = 0.7 cm/s) for Z. marina seeds determined from laboratory flume experiments. We postulate that small-scale topographic features on the bottom (burrows, pits, mounds, ripples) shield the seeds from the flow. Our results suggest that seeds settle rapidly, dispersing only up to a few metres under the influence of currents and become rapidly incorporated into the sediment. The limited dispersal capabilities of seeds underscore the need to address restoration goals and questions of seagrass ecology in the context of landscape-scale distributional patterns and metapopula- tion analyses.

/pdf/seed-dispersal-in-a-marine-macrophyte-implications-for-3gehfq16ck.pdf

Mark W. Luckenbach

Papers

Oyster Reefs at Risk and Recommendations for Conservation, Restoration, and Management

Ecosystem services related to oyster restoration

Developing success criteria and goals for evaluating oyster reef restoration: Ecological function or resource exploitation?

Seed Dispersal in a Marine Macrophyte: Implications for Colonization and Restoration

The role of oyster reefs as essential fish habitat: a review of current knowledge and some new perspectives