Paleoecologic Record

Imagine a community ecologist venturing into the literature of marine paleoecology for the first time. Let us say that her first exposure will be in the reading of a volume of contributed chapters, such as this one. If our colleague scratches her head each time she is confused over inconsistent and illogical usage of unit definitions, by the end of the book she might be bald. This would be no reflection on the quality of data or analytical rigor in such volumes, but rather a consequence of a...

References

Cataudella, J. R. Powell, and V. Sbordoni. 1995. Acclimation of the European sea bass to freshwater Monitoring genetic changes by RAPD polymerase chain reaction to detect DNA polymorphisms. Marine Biology 121 591-599. Avise, J. C. 1992. Molecular population structure and the biogeographic history of a regional fauna A case history with lessons for conservation biology. Oikos 63 62-76. Bambach, R. K. and J. B. Bennington. 1996. Do communities evolve A major...

Nutrients and Evolution in the Marine Realm

It is a central theme of ecology that energy flow is one of the most important aspects of any biological community or ecosystem (e.g., Ricklefs 1990 Begon, Harper, and Townsend 1996). Under various terms (e.g., trophic structure, nutrient cycling, etc.), the causes and effects of energy transfer and how it is accomplished among organisms and taxa are virtually universally viewed as among the basic organizing factors of the biosphere. This is an ecological view. When this view is expanded to...

The Diversity Pyramid

Within many clades, the species richness of various trophic levels parallels productivity at those levels (figure 7.1). As noted long ago by Elton (1927), the ecological efficiency of a community dictates that only a fraction of the productivity at one trophic level will be transferred to the next highest level, producing a pyramid herbivore production may, for example, be only 20 of plant production and first-level carnivore production may be only 15 of herbivore production, and therefore only...

Resistance versus Resilience

Resistance is the ability of a community to withstand perturbations without significant change, whereas resilience refers to the ability of a community to rebound to initial conditions after experiencing a disturbance (Grimm and Wissel 1997, and references therein). Having high resistance does not necessarily confer high resilience upon a community and vice versa. In fact, the opposite may be true resistance may be negatively correlated with resilience. For example, -selected populations...

Late Neogene Faunal Change in the Western Atlantic

The late Cenozoic (i.e., Pliocene-Recent, the last five million years) marine fossil record of the Western Atlantic region, especially in the Caribbean, Central America, and the Coastal Plain of the southeastern United States is a particularly appropriate record in which to study the connection between environmental and faunal change because of the dramatic paleoceanographic changes associated with the rise of the Central American Isthmus (CAI). Of special interest in much work on the Western...

E

Environmental Parameter Environmental Parameter FIGURE 5.2. A two-dimensional schematic to illustrate the difference between (A) a dynamically fragile community versus (B) a robust one. A dynamically fragile community (or species) would be able to exhibit stability within a limited range of environmental conditions, whereas a robust one could withstand a wide range of conditions. (After Begon, Harper, and Townsend 1996) Environmental Parameter Environmental Parameter FIGURE 5.2. A...

Stability Over Neontological Timescales

We are currently in a period of global change in which extinctions and invasions of new habitats are proceeding quickly. Thus, it is clearly important to understand if and how ecosystems react to physical and ecological perturbations. There are documented cases in which the introduction of exotic species into new ecosystems had little effect on the native fauna (e.g., Simberloff 1981), which suggests that stability is quite predominant. In other examples, the introductions have caused local...

Coral Reproductive Strategies

Corals reproduce asexually, primarily by fragmentation. They also employ two strategies of sexual reproduction broadcast spawning of gametes and release of brooded planula larvae (Szmant 1986 Richmond and Hunter 1990 Smith 1992 Richmond 1997). Slow recovery times of populations of A. palmata, A. cervicornis, and (to a lesser extent) M. annularis complex can be tied to their reproductive strategies. The key to success for A. cervicornis prior to 1980 was rapid growth coupled with reproduction by...

The Ecological Architecture of Major Events in the Phanerozoic History of Marine Invertebrate Life

Droser, Peter M. Sheehan, and George R. McGhee Jr. the history of life is punctuated by mass extinctions, their recoveries, and radiations. Although the recognition and understanding of these events comes largely from taxonomic data, researchers have striven to evaluate changing ecologies associated with these events. However, evolutionary paleoecologists are still in the early stages of recognizing the particular paleoecological patterns that are associated with...

Discussion

Although patterns of relationship shared among populations of a single species should not be used to draw general biogeographic conclusions Brooks and McLennan 1991 , area relationships in A. plicata can be instructive if compared with results of other codistributed species to consider more general biogeographic patterns, patterns of phylogeographic association, and thus also patterns of ecological interaction over long periods of time. To do this, it is necessary to assume that the populations...

Dynamically Fragile versus Dynamically Robust Communities

Communities that are stable only under a limited range of environmental and ecological conditions are considered dynamically fragile, whereas communities that are stable over a wide range of conditions are dynamically robust. Figure 5.2 is a two-dimensional representation of the difference between a dynamically fragile and a dynamically robust system. Of course, a hypervolume with numerous axes would more adequately represent natural environmental conditions. A fragile community is one in which...

Underpinnings of Mass Extinction Taxonomic and Ecological Decoupling

Perhaps one of the most interesting aspects of this analysis of mass extinctions using our approach of paleoecological levels is the phenomenon that we term taxonomic and ecological decoupling, where the relative level of ecological degradation is not as great as the degree of taxonomic degradation during a mass extinction event Droser et al. 2000 . This ecological decoupling appears to occur at the second paleoecological level. For example, as discussed, the Late Ordovician mass extinction,...

Reclining

General adaptive benthic strategies that are typical of A the Cambrian Evolutionary Fauna and B the Ordovician representatives of the Cambrian and Paleozoic Evolutionary Faunas after Bambach 1983 . The shaded boxes are not biologically practical strategies. Second-level changes from A to B include the addition of new Bambachian megaguilds. Third-level changes include the filling-in of Bambachian megaguilds after Droser and Sheehan 1995 . FIGURE 4.1. General adaptive benthic...

Origin of the Modern Coral Fauna of the Caribbean

The present-day coral fauna of the Caribbean is very unlike that of the Indo-Pacific, although both originated from the same Eocene-Oligocene pantropi-cal species pool. Many of these differences can be traced to two intervals of evolutionary change in the Caribbean A regional extinction in the early Miocene and a period of accelerated turnover during the Plio-Pleistocene. These two formative episodes affected both the taxonomic composition and ecological attributes of the fauna. Following an...

Evolutionary Paleoecology of Caribbean Coral Reefs

Precht ecologists have radically altered their thinking about coral reefs, and those views continue to evolve. Coral reefs, formerly viewed as stable, equilibrial systems Newell 1971 , are now interpreted as nonequilib-rial on ecologically relevant scales of time years to decades and space landscapes to reef systems Grigg and Dollar 1990 Karlson and Hurd 1993 Edmunds and Bruno 1996 Brown 1997 . Increasing awareness of this variability is motivating a strategic...