SCOTT A. MANGAN

Education:

Thesis research:  The consumption of arbuscular mycorrhizal fungi by Neotropical rodents

Identifying complex interactions that are important in tropical-forest regeneration and maintenance has been a priority for ecologists due to the ever-increasing rates of deforestation in tropical regions.  Much attention has been placed on rodents because they influence successful tree establishment by acting as both seed dispersers and predators.  In the Neotropics, successful establishment of tree seedlings often requires the mutualistic association formed with arbuscular mycorrhizal fungi (AMF).  In temperate regions, small mammals commonly consume the fruiting bodies of mycorrhizal fungi and pass most spores in viable condition.  If fungus consumption (mycophagy) is equally as common in tropical small mammals, then rodents also may influence seedling survival by dispersing AMF in tropical regions.  This thesis examines the consumption of AMF by rodents residing in two different tropical ecosystems.

Proechimys semispinosus (the Central American spiny rat) residing on small islands in Gatun Lake, Panama commonly included several species of AMF in their diets.  Mycophagy was highly seasonal and strongly correlated with soil moisture, with spores being more frequent in fecal pellets during mid to late rainy season.  AMF consumption did not differ between islands that were experimentally provisioned with extra food and islands that remained unmanipulated.  P. semispinosus largely consumes AMF regardless of natural fruit and seed availability, suggesting that fungi are probably essential dietary items when available.  AMF spores were found in several species of rodents and marsupials of montane cloud forest in western Panama.  The common occurrence of AMF spores in feces of Reithrodontomys mexicanus, a primarily arboreal rodent, suggests that this species may be important in dispersing AMF to epiphytes in the forest canopy.

Like small mammals in temperate regions, tropical rodents commonly consume mycorrhizal fungi.  Further experimental studies are required to elucidate the importance of these rodents as AMF spore dispersers in tropical regions.

Publications (while in The Topical Rat Lab):


Grants (while in The Tropical Rat Lab)


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Last updated 12 February 2002.