Ecology of seasonal flooding in tropical ecosystems

Flooding, tree cover, and tropical biomes
Flooding is a massive ecological disturbance, which can kill terrestrial plants by
creating soil anoxia. Therefore, differential flood regimes can regulate the
abundance of tree cover, a crucial determinant of biome structure:  grasslands
have few trees, savannas have moderate tree cover, and forests are heavily
treed. However, existing models for the determinants of tropical vegetation
structure exclude flooded ecosystems. Meanwhile, the estimated 9% of 
tropical terrestrial ecosystems (>5 million km^2) that experience periodical
flooding are highly  productive environments which sustain large aggregations
of seasonally migratory (terrestrial and aquatic) wildlife, and provide rich fishing
grounds for many human communities. Furthermore, seasonally inundated
ecosystems  include forests (e.g., the Amazonian varzea), savannas
(Australia’s Kakadu National Park and the South American Pantanal), and
grasslands (e.g., Botswana’s Okavango Delta and the Florida Everglades), leaving
it unclear why trees respond to flooding in varied ways. I am using a range of
remote sensing datasets and field-based data to understand which aspects of
flood regimes (e.g., frequency, regularity, and duration), other environmental
conditions (e.g., rainfall and fire), and species traits determine tree responses to
inundation across the global tropics.

Ecology and conservation of a seasonally flooded tropical savanna
Although sometimes deadly for terrestrial species, floodwaters facilitate many other plants and animals, either as a dispersal agent (e.g., for fish, amphibians, and seeds), or as a source of water (e.g., annual hydration of floodplain grasslands which provide forage for African mammals including elephants and various antelope). I have ongoing projects regarding

     (1) the effects of climate and land use change on the ecologically crucial annual inundation of the Lake Urema floodplain (see video      above) in Mozambique’s Gorongosa National Park ,
     
     (2) and how the spatial spread of floodwaters in Gorongosa affects fish, amphibian, and invertebrate community composition in          the park’s many seasonal ponds.
 
  
Click to see the massive annual flooding of Gorongosa National Park's Lake Urema floodplain in Mozambique. Plants here are nourished by the annual floodwaters, providing forage for the park's antelope, elephants, and other species. The lake also contains robust waterbird, crocodile, and fish poupulations., and the flooding extends into the drier savannas, dispersing aquatic species and shaping animal and plant community composition.