Issues With The Wildland-Urban Interface In South Florida Jon Moore & Vincent del Signore Wilkes Honors College, Florida Atlantic University
What Is Happening? Increasing urbanization has moved into rural areas Exurbs = towns being built beyond suburbs, adjacent to rural and wild lands 2000-2010 US population grew 10% Exurban population grew 60%
Some Reasons Folks Move To Exurbs Nearby recreation in natural areas Visual appeal Increased privacy Escape problems of urban areas Higher property values
Impact of Exurbanization Increasing human influence on edges of southern wildlands challenge natural area managers Some traditional methods of management no longer work in these areas Newcomers to WUI bring different values, attitudes, lifestyles and perceptions of how wildlands should be used and managed They likely do not understand how wildlands in Florida ecologically function
Impacts of Exurbanization Habitat loss and fragmentation of wildlands Increased roadkill Water quality changes Loss of native diversity Introduced species More interactions with dangerous native species Increased populations of native commensals (e.g., blue jays, raccoons, coyote) Fire suppression Poaching Dumping of trash or yard waste
Habitat Fragmentation North end of Savannas Preserve State Park showing habitat fragmentation
Increased Roadkill
Introduced Species Sanseviera in Hobe Sound NWR scrub
Dangerous Native Species
Commensals Gone Wild Raccoons at Hugh Taylor Birch State Park
Poached Gopher Tortoises in 2011
Yard Waste Thrown Over Fence
Abacoa Greenway System FAU Honors College campus was designed into a 2050-acre planned community in Jupiter, FL called Abacoa Abacoa includes a 267- acre greenway system as natural habitat corridor running through the community Jupiter
Greenways University
Water Flow & Water Quality in Abacoa
Range VIa in Abacoa 9.16 Hectare (22.9 Acre) Site N Fredrick Small Rd Pipe line Aerial photo from 2000 Cattle fenceline Central Blvd Catchment basin 90 m 1 Figure 1. Aerial photograph of the study site, Range VIa.
Invasives In Wildland Curlytails have followed sidewalks and moved into greenway and now take refuge in gopher tortoise burrows Domestic variety of coco plum now sprouting in the center of range This species is used as hedge along fence at periphery of range Likely dispersed by tortoises which eat dropped fruit
Cultivars In Greenway Cultivated variety of agave next to gopher tortoise burrow
Abacoa Greenway System Problems: Large overgrowth of vegetation, no fire since before 1997 Public objections to use of fire near homes Tortoises forced to the open periphery of the site Grounds-keeping trucks accidentally collapse some burrows along paths Objective: Restore interior landscape back to a state that is conducive for gopher tortoise use
Range VIa Tortoise Burrow Locations Jan 2001 to Jan 2005
Oct 2001
Feb 2004
Locations of new burrows from May 2003 to Sept 2006 (B200-B274)
Burrows crushed closed by grounds keeping trucks and mowers during May 2003 to Sept 2006
Herbicide Management of Wild Grape
The Reduction Mowing October 25, 2006 mowing began, took 8 working days to mow site Large mowers chopped down saw palmetto and ground stumps Thick layer of mulch left over
Before and After the Mowing BEFORE (day of mowing) AFTER (2 days later)
Same View 1 Year Later (2007)
Same View Yesterday
Interior vs. Peripheral Areas
Active and New Burrows for 6 Months Prior to Mowing
Active and New Burrows for 6 Months After Mowing
Heavy layer of mulch where palmettos were thick, but many smaller open patches of grasses and herbs left alone Flagged burrows and surrounding palmettos left intact Several new burrows and several inactive or abandoned burrows re-excavated and re-occupied in interior Results of Mowing
Unintended Consequences Woody plants with deep roots grew back quickly and filled in greater proportion of space Visible re-growth of palmetto, grasses, gopher apple, runner oak and gallberry Several plants took longer to reappear: pine lily, deer moss Mulch suppressed several herbaceous plants, may have destroyed seed bank
Gallberry Stands Take Over
Unintended Consequences Mulch on ground may have also fostered spread of invasive Little red fire ant Wasmannia auropunctata
Wasmannia Ants in 2002
Wasmannia Ants in 2008
Conclusions Prescribed burns are frowned upon in urban areas, so alternative methods for conservation of scrubby flatwoods and scrub habitat are necessary Because the mowing creates a thick layer of mulch and debris, smaller growing forbs and grasses are initially impeded from growth This may have a significant effect on protected plant species (e.g., Polygala smallii) Follow up maintenance is necessary to continually regulate this habitat Removing non-native invasives Mowing needed about every 8-10 years in Abacoa Raking of some mulch Root-raking to remove some woody plants and create open patches
Questions?