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August 3, 2005

Chapter 13 - Fragile environments: the biogeography of existence.

New books and papers | Websites

Chapter Outline :

    • Fragile environments are one of the commonest ideas in biogeography and yet the concept is not well defined ecologically;
    • Fragility is better considered in terms of the notions of extinction (loss of species) and origination (gaining new species);
    • Examination of the concept of species loss and gain shows it to be a complex system of the interplay of genetics, organisation and chaos dynamics;
    • These factors can be placed in a model to better explain the loss and gain of species;
    • Examples of fragile ecosystems and threatened species need to be studied to better enable us to appreciate the factors which can cause catastrophic changes in ecosystems. It is clear that this will be one of the most urgent tasks facing biogeographers in the twenty-first century.
New books and papers
Author(s) Title (and link) Comment
Andersen and Krzywinski 2007 Mortality, Recruitment and Change of Desert Tree Populations in a Hyper-Arid Environment Extreme environments continue to oofer us insights into biogeographical change. Here's a study showing that human intervention and difficult recruitment can cause severe decline.
Smol and Douglas 2007 Crossing the final ecological threshold in high Arctic ponds Arctic areas are fragile environments and their ponds are especially vulnerable whilst also having high biodiversity. Global warming may change all of this.
Vamosi et al 2006 Pollination decays in biodiversity hotspots As pollinators become rarer their loss will be felt most keenly in species-rich areas.
Brook et al 2006 Minimum viable population sizes and global extinction risk are unrelated Extinction risks might be more related to external factors such as human pressure rather than the population going below its MVP level.
Fagan and Holmes 2006 Quantifying the extinction vortex Extinction patterns appear to be log-realtionships which has important implications for extinction dynamics.
Hoyle and James 2005 Global Warming, Human Population Pressure, and Viability of the World’s Smallest Butterfly Species loss is fastest where climate cnage acts togehter with human pressure
 Mills and Schwartz. 2005.  Rare plants at the extremes of distribution: broadly and narrowly distributed rare species  There are two types of rarity: endemism and suffusively rare each with their own lifeform characterisitcs and conservation needs.

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