Definitions of diversity. Measuring species diversity. Choosing an index and interpreting diversity measures. Sampling problems. Structural diversity. Applications of diversity measures. Summary.

/pdf/ecological-diversity-and-its-measurement-4az8bcrmxt.pdf

Ecological Diversity and its Measurement

Since 65 million years ago (Ma), Earth's climate has undergone a significant and complex evolution, the finer details of which are now coming to light through investigations of deep-sea sediment cores. This evolution includes gradual trends of warming and cooling driven by tectonic processes on time scales of 10(5) to 10(7) years, rhythmic or periodic cycles driven by orbital processes with 10(4)- to 10(6)-year cyclicity, and rare rapid aberrant shifts and extreme climate transients with durations of 10(3) to 10(5) years. Here, recent progress in defining the evolution of global climate over the Cenozoic Era is reviewed. We focus primarily on the periodic and anomalous components of variability over the early portion of this era, as constrained by the latest generation of deep-sea isotope records. We also consider how this improved perspective has led to the recognition of previously unforeseen mechanisms for altering climate.

/pdf/trends-rhythms-and-aberrations-in-global-climate-65-ma-to-cflhxkixnq.pdf

Trends, Rhythms, and Aberrations in Global Climate 65 Ma to Present

Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including pollution, degradation of water quality, and anthropogenic climate change. Historical abundances of large consumer species were fantastically large in comparison with recent observations. Paleoecological, archaeological, and historical data show that time lags of decades to centuries occurred between the onset of overfishing and consequent changes in ecological communities, because unfished species of similar trophic level assumed the ecological roles of overfished species until they too were overfished or died of epidemic diseases related to overcrowding. Retrospective data not only help to clarify underlying causes and rates of ecological change, but they also demonstrate achievable goals for restoration and management of coastal ecosystems that could not even be contemplated based on the limited perspective of recent observations alone.

/pdf/historical-overfishing-and-the-recent-collapse-of-coastal-28k1p5mqjm.pdf

Historical overfishing and the recent collapse of coastal ecosystems.

Interactions between organisms are a major determinant of the distribution and abundance of species. Ecology textbooks (e.g., Ricklefs 1984, Krebs 1985, Begon et al. 1990) summarise these important interactions as intra- and interspecific competition for abiotic and biotic resources, predation, parasitism and mutualism. Conspicuously lacking from the list of key processes in most text books is the role that many organisms play in the creation, modification and maintenance of habitats. These activities do not involve direct trophic interactions between species, but they are nevertheless important and common. The ecological literature is rich in examples of habitat modification by organisms, some of which have been extensively studied (e.g. Thayer 1979, Naiman et al. 1988).

Organisms as ecosystem engineers

The management and conservation of the world's oceans require synthesis of spatial data on the distribution and intensity of human activities and the overlap of their impacts on marine ecosystems. We developed an ecosystem-specific, multiscale spatial model to synthesize 17 global data sets of anthropogenic drivers of ecological change for 20 marine ecosystems. Our analysis indicates that no area is unaffected by human influence and that a large fraction (41%) is strongly affected by multiple drivers. However, large areas of relatively little human impact remain, particularly near the poles. The analytical process and resulting maps provide flexible tools for regional and global efforts to allocate conservation resources; to implement ecosystem-based management; and to inform marine spatial planning, education, and basic research.

/pdf/a-global-map-of-human-impact-on-marine-ecosystems-1r5xgg00oe.pdf

A Global Map of Human Impact on Marine Ecosystems

A sediment trap intercomparison study in the Santa Barbara Basin

[1] The coral reef hypothesis asserts that carbonate production on newly flooded shelves contributes importantly to the rise of atmospheric carbon dioxide during deglaciation. We seek to constrain the timing and strength of such carbon dioxide flux by re-assessing reef and platform distribution in the world ocean. The pattern of reef growth that emerges suggests that emission of CO 2 resulting from carbonate production was important particularly during the late stages of deglaciation. The effect peaked during the early Holocene and presumably contributed to the warming in the climatic optimum.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2003GB002147

Wolfgang H Berger

Papers

A sediment trap intercomparison study in the Santa Barbara Basin

Increase of atmospheric CO2 during deglaciation: Constraints on the coral reef hypothesis from patterns of deposition

The sea floor

Dissolution of deep-sea carbonates

On the determination of Pleistocene temperature from planktonic foraminifera