Issues With The Wildland-Urban Interface In South Florida

Transcription

1 Issues With The Wildland-Urban Interface In South Florida Jon Moore & Vincent del Signore Wilkes Honors College, Florida Atlantic University

2 What Is Happening? Increasing urbanization has moved into rural areas Exurbs = towns being built beyond suburbs, adjacent to rural and wild lands US population grew 10% Exurban population grew 60%

3 Some Reasons Folks Move To Exurbs Nearby recreation in natural areas Visual appeal Increased privacy Escape problems of urban areas Higher property values

4 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

5 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

6 Habitat Fragmentation North end of Savannas Preserve State Park showing habitat fragmentation

7 Increased Roadkill

8 Introduced Species Sanseviera in Hobe Sound NWR scrub

9 Dangerous Native Species

10 Commensals Gone Wild Raccoons at Hugh Taylor Birch State Park

11 Poached Gopher Tortoises in 2011

12 Yard Waste Thrown Over Fence

13 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

14 Greenways University

15 Water Flow & Water Quality in Abacoa

16 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.

17 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

18 Cultivars In Greenway Cultivated variety of agave next to gopher tortoise burrow

19 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

20 Range VIa Tortoise Burrow Locations Jan 2001 to Jan 2005

21 Oct 2001

22 Feb 2004

23 Locations of new burrows from May 2003 to Sept 2006 (B200-B274)

24 Burrows crushed closed by grounds keeping trucks and mowers during May 2003 to Sept 2006

25 Herbicide Management of Wild Grape

26 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

27 Before and After the Mowing BEFORE (day of mowing) AFTER (2 days later)

28 Same View 1 Year Later (2007)

29 Same View Yesterday

30 Interior vs. Peripheral Areas

31 Active and New Burrows for 6 Months Prior to Mowing

32 Active and New Burrows for 6 Months After Mowing

33 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

34 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

35 Gallberry Stands Take Over

36 Unintended Consequences Mulch on ground may have also fostered spread of invasive Little red fire ant Wasmannia auropunctata

37 Wasmannia Ants in 2002

38 Wasmannia Ants in 2008

39 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

40 Questions?