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Estes et al. 2011 paper discussion
 

Estes et al. 2011 paper discussion

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Discussion on the trophic downgrading of Planet Earth by Sofia Olivero Lora.

Discussion on the trophic downgrading of Planet Earth by Sofia Olivero Lora.

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    Estes et al. 2011 paper discussion Estes et al. 2011 paper discussion Presentation Transcript

    • Trophic Downgrading of Planet Earth Sofia Olivero Lora November 29, 2012 Estes et al. 2011
    • Mass extinction events (http://evolution.berkeley.edu)
    • (http://evolution.berkeley.edu)
    • 6th mass extinction• Early to middle stages• Differences – Homo sapiens – Loos larger-bodied animals in general, apex consumers in particular• Global occurrence
    • Apex consumers• Global and perpetual• Effects on processes – Carbon sequestration, invasive species, biogeochemical exchanges, etc.• Removal-trophic downgrading
    • Trophic cascade http://pubs.usgs.gov/fs/2010/3099/
    • http://www.ucc.ie/staff/memmers/Lough%20Hyne.htm
    • Alternative stable states• Sets of unique biotic and abiotic conditions• Basins of attraction – Set of individual conditions lead to long-time behavior – Collection of all possible initial conditions of a dynamical state• ASS- perturbations push ecosystem from one basin to another
    • Alternative stable states• Tipping points – Phase shifts – abrupt changes in ecosystem structure and function.• Hysteresis – Multiple states persist under equal environmental conditions – Example: Tropical cloud forests
    • Connectivity• Ecosystems are built around interaction webs• Every species can potentially influence many others• Interactions – Biological processes – Physicochemical processes – Highly complex network
    • Ecological Society of Americahttp://phys.org/news/2012-10-scientists-greenbelts-wildlife-sanctuaries.html
    • Trophic Downgrading• Not widely appreciated, difficult to observe• Need for perturbation, to be perceived• Time scales – When noticed, too late• Space scales
    • • Sea Otter (nutria) – Population collapse – -herbivorous sea urchins – +kelp abundance• Seastar – Prevents dominance mussels (mejillon)• Bass (robalo) – Reduce phytoplankton – Eats zooplanktivorous• Large reef fish – Fisheries (left)• Bass – Eats minnows – Promotes benthic algae
    • • Artic fox (zorro) – Eat seabirds – Reduces nutrients inputs from sea to land• Jaguar – Herbivore guild – Reduction plant recruitment and survival• Wolf – Elk (alce) browsing• Wildebeest (gorgon) – Rinderpest (virus) – Increase biomass-fire
    • • Kelp increase enhances abundance of kelp forest fish• Increases organic carbon- +growth rate of mussels• Gulls (gaviotas) – Fish- invertebrates• Fish, mammals, birds
    • Discussion• Management solution: restoration of apex consumers.• Ecological surprises – Pandemics, loss valuable sp., shifts ecosystem states, loss ES – Altered top-down regimes – Apex loss or introduction of exotics
    • Discussion• What about other anthropogenic threats?• Do present conservation strategies contemplate this new paradigm?
    • Surrogate species?Species used to represent other species or aspects of the environment to obtain a conservation objective. (Caro, 2010) Indicator Umbrella Keystone Flagship
    • Thanks for your attention!