Effects of environmental disturbances and land-use on semi-deciduous forests in Yucatán, Mexico.

John Rogan, Clark University, jrogan@clarku.edu
Laura Schneider, Rutgers University, laschnei@rci.rutgers.edu (Presenter)
Zachary Christman, Middlebury College, zjc@zachxman.com
Irene Zager, Rutgers University, izager@eden.rutgers.edu
Schmook Birgit, ECOSUR, bschmook@ecosur.mx
Miguel Mendez, Calakmul Biosphere Reserve, mmendez@conanp.gob.mx

In the Mexican Yucatán forest fragments and biosphere reserves exist within a matrix of cattle pastures and slash-and-burn farming plots that are regularly burned. Ongoing deforestation and fragmentation leaves many remaining forest edges vulnerable to fire particularly during severe drought years. We explore the linkages between wildfire occurrence, frequency and severity and landscape characteristics including land-use, forest fragments, and hurricane damage in the four years following Hurricane Dean, an August 2007 Category-5 wind event. We examined the spatio-temporal behavior of all dry-season fire events from 2007 to 2011 using a combination of field records, official statistics and MODIS Active Fire data. Then we focus on three April-May (2011) wildfires that were ignited to clear cattle pastures, then escaped and spread quickly to the forest of the Calakmul Biosphere Reserve. A combination of plot-level burn severity data and pre- vs. post-fire Quickbird-2 imagery are used to map the burn severity and examine the linkages between severity, forest composition/configuration, and level of hurricane damage. Results reveal a three-year time lag between the hurricane event and abnormal levels of wildfire occurrence, in terms of spatial and temporal frequency. The dry-season of 2011 was the most wildfire prone season of the decade – the outcome of a prolonged five-year regional drought, desiccated wind thrown fuels, and ubiquitous fires for pasture maintenance along forest edges. The three 2011 caused stand-replacement in over 60% of the affected area, and likely a future 20% mortality in the remaining fragments. Burn severity was highest along forest edges that abutted pastures, which also sustained high levels of branch damage and uprooting during Hurricane Dean in 2007. Current conditions of ubiquitous wildfire ignitions, extensive land clearing for cattle pasture, fragmentation and damage to forests may combine to make large regions of the Yucatán vulnerable to fire conversion to early successional and impoverished conditions.

Presentation Type:  Poster

Session:  Other   (Wed 10:00 AM)

Associated Project(s): 

• Related Activity

Poster Location ID: 248