Rapid Assessment of Threats to Wildlife Corridors in ...conservation.dcp.ufl.edu/RA_Report_March 2011.pdf · The Rapid Assessment of Threats to Wildlife Corridors in Southwest Florida,

Rapid Assessment of Threats to Wildlife Corridorsin Southwest Florida

part of the

Florida Fish and Wildlife Conservation Commission’s Cooperative Conservation Blueprint Regional Pilot Project

prepared by

The Center for Landscape Conservation Planning, University of Floridaand

Florida Natural Areas InventoryMarch 2011

The Center for Landscape Conservation Planning, University of Florida Florida Natural Areas Inventory

Rapid Assessment of Corridor Threats, March 2011 Cooperative Conservation Blueprint Regional Pilot Project

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ContentsAbstract 3

Introduction 4Potential Individual Threats to Wildlife Corridors 8

Synthesis of Potential Threats to Wildlife Corridors 18Conclusions 23Works Cited 24

List of Acronyms / AbbreviationsCCB Pilot: Cooperative Conservation Blueprint Regional Pilot Project

CLC: Cooperative Land Cover ProjectCLU: Current Land Use

DCA: Florida Department of Community AffairsDRI: Development of Regional Impact

FLU: Future Land UseFNAI: Florida Natural Areas Inventory

FWC: Florida Fish and Wildlife Conservation CommissionGeoPlan: University of Florida GeoPlan Center

IHN: Integrated Habitat NetworkModCon: Moderate Connectivity Model

RA: Rapid Assessment of Threats to Wildlife Corridors in Southwest FloridaSLR: Sea Level Rise

Cover Image Credits:Landscape: bing.com/maps

Panther: sierraclubfloridanews.orgSherman’s fox squirrel: flickr.com

Black bear: blogs.trb.com



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Abstract

The Rapid Assessment of Threats to Wildlife Corridors in Southwest Florida, a spatial analysis conducted in late 2010 and early 2011 by the University of Florida Center for Landscape Conservation Planning and the Florida Natural Areas Inventory, compared a representation of potential priority areas for conservation in southwest Florida, including wildlife corridors, with representations of five potentially corridor-inhibiting factors. These factors were current land use, parcel fragmentation, future land use, developments of regional impact, and sea level rise. Each factor was compared individually with the representation of potential priority areas for conservation, yielding five single threat analyses, which were then combined in two different ways to produce a pair of combined threat-syntheses. The individual analyses and especially the syntheses identify potential hazards to wildlife corridors in southwest Florida. Several strategic nodes and linkages face multiple potential hazards, and corridor threats, while not particularly extensive, tend to cluster in corridor-blocking bands or clumps. We recommend that regional corridor conservation efforts include a focus on these potential blockages.



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Introduction

The Rapid Assessment of Threats to Wildlife Corridors in South-west Florida (RA) is a spatial analysis conducted by the University of Florida Center for Landscape Conservation Planning and the Florida Natural Areas Inventory between December 2010 and March 2011. It comprises one portion of the Florida Fish and Wildlife Conservation Commission’s Cooperative Conservation Blueprint Regional Pilot Project (CCB Pilot), an ongoing effort to develop conservation incentives based on region-specific natural resources, funding opportunities, and landowner interests. The CCB Pilot includes all or portions of fourteen peninsular Florida counties (see Map 1), most of which are included in the RA study area (Map 2). (The RA study area will also touch upon counties outside the CCB pilot study area.) As existing conservation lands--shaded gray in Map 2--are not considered subject to the threats analyzed herein, they are not included in the RA.

The RA’s focus, then, is the natural and semi-natural corridors linking existing conservation areas in southwest Florida. In this study, these corridors will be represented by the Moderate Con-nectivity Model introduced by Noss and Hoctor (2010) in their report to the Babcock Ranch Steering Committee. The Moder-ate Connectivity Model (ModCon) is a spatial dataset including

core habitat for several species studied by Noss and Hoctor, along with buffered least-cost paths linking these habitat areas (Map 3). To these habitat areas and least-cost linkages, Noss and Hoctor added what is known as the Integrated Habitat Network (IHN), which appears in light green in Map 3. This addition was designed to represent wildlife habitat and corridors in the Peace and Myakka River valleys and in Manatee and Hillsborough Counties. Thus the Moderate Connectivity Model includes core habitat for Noss and Hoctor’s focal species, linkages between these cores, and the IHN. For a more complete explanation of the Moderate Connectivity Model, see Noss and Hoctor 2010.

For the RA, the non-IHN portion Moderate Connectivity Model--including portions within existing conservation lands--was buff-ered by one mile (Map 4). The rationale for this decision is that corridor function depends to a degree upon surrounding land uses, and that the buffers could also represent additional areas to support implementation of corridors if revisions in paths were needed to avoid potential threats. While this rationale no doubt also applies to the IHN, buffering this complex network would have brought into the analysis what was felt to be excessive acre-age. Map 4 is thus the foundation for the RA, delineating the

RA Study Area

Map 1 Map 2



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Map 3



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Map 4

Rapid Assessment of Threats: Moderate Connectivity Model with 1 Mile Buffer of Core Components



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Moderate Connectivity Model (including the IHN) and its buffer. That is, Map 4 shows the corridors whose exposure to various potential threats is analyzed by the RA.

We define potential threats as changes in land use or land cover within or near corridors which could inhibit their functional con-nectivity. While there are likely dozens of connectivity-inhibiting factors, we focused on five for which spatial datasets were readily available and whose negative impact on corridor func-tion is widely accepted. These five potential threats are briefly described below:

I. Potential current-land-use-related threats: Intensive land uses, such as commercial and residential development, often function as barriers to wildlife movement, inhibiting func-tional connectivity (see Forman 1995). II. Potential ownership-related threats: Areas consisting of small parcels (e.g., parcels of less than 100 acres) are less conducive to wildlife movement than those consisting of larger parcels. Generally speaking, a relatively high propor-tion of a small parcel’s area is likely to be developed. In ad-dition, clusters of small parcels tend to correlate with higher road densities, which often impede wildlife movement. Furthermore, areas dominated by small parcels are likely to

have many different owners, which often makes them more difficult to protect. III. Potential future-land-use-related threats: Corridor lands and buffers slated for intensive uses will likely experience reduced functionality on par with those already intensively developed. IV. Potential DRI-related threats: Where approved by regula-tors, Developments of Regional Impact (DRIs), large-scale developments whose effects are expected to extend beyond their immediate surroundings, are more likely to develop than are other areas (Zwick and Carr 2006). V. Potential sea-level-rise-related threats: For many terres-trial species, wider rivers or newly submerged lands will likely represent a barrier or hindrance to movement.

The RA therefore compares spatial datasets representing these five threats with the corridor network shown in Map 4 (the buffered Moderate Connectivity Model), identifying portions of southwest Florida’s wildlife corridors subject to potential reduced functionality. In an effort to summarize these findings, the RA also compiles the various individual threats into three representations of cumulative corridor threats. The following pages describe the five individual analyses and their two compi-lations and provide brief analysis of each.



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Potential Individual Threats to Wildlife Corridors

Table 1 summarizes the analyses of potential individual threats to wildlife corridors. In each analysis, an input dataset was first sorted (reclassified) so as to represent various threat levels to corridor functionality, and this reclassified dataset was then compared to the Moderate Connectivity Model. This section briefly describes the individual analyses and analyzes their re-sults. (These descriptions and analyses are meant to be intro-ductory rather than comprehensive.)

I. Potential current-land-use-related threats. Given that inten-sive land uses reduce wildlife corridor functionality, this analysis sorted a spatial representation of existing land uses--FNAI’s Co-operative Land Cover dataset--into intensive and non-intensive categories, removed intensive land uses of less than five acres, and then compared the resulting dataset with the Moderate Connectivity Model. Table 2 shows the CLC land use / land cover categories considered intensive for this analysis, while Table 3 and Map 5 summarize its results.

Rapid Assessment of Potential Threats to Wildlife Corridors2/26/2011PART 1: POTENTIAL CURRENT‐LAND‐USE‐RELATED THREATSCURRENT LAND USE THREAT TO CORRIDORS GRID VALUEINTENSIVE (SEE RA_Intsv_CLU_201102133.xls for details) high 1_ _ _ gNON‐INTENSIVE low 9

PART 2: POTENTIAL OWNERSHIP‐RELATED THREATSPARCEL SIZE THREAT TO CORRIDORS GRID VALUE100 ACRES OR MORE none 9NO DATA (PORTIONS OF HIGHLANDS) unknown 5LESS THAN 100 ACRES high 1

PART 3: POTENTIAL FUTURE‐LAND‐USE‐RELATED THREATSSTATE FLU DESCRIPTION THREAT TO CORRIDORS GRID VALUEAGRICULTURE ‐ RURAL LAND, FARMS < 0.5DU (AG) none 9COMMERCIAL, OFFICE, TOURISM, MARINA (COM) high 1CONSERVATION, NATURAL AND PROTECTED (CONS) none 9INDUSTRIAL, EXTRACTIVE, TRANSPORTATION (IND) mod‐high 3MIXED USE, ACTIVITY CTR, URBAN VILLAGE (MU) high 1, , ( ) gMUNICIPALITY, INFORMATION NOT AVAILABLE (CITY) moderate 7PUBLIC/SEMI‐PUBLIC, GOV, INSTITUTIONAL (PUB) moderate 5RECREATION/OPEN SPACE (REC) none 9RESIDENTIAL HIGH MORE THAN RM AND > 12DU (RH) high 1RESIDENTIAL LO HIGHER THAN AG < 1DU (RL) high 2( ) gRESIDENTIAL MEDIUM MORE THAN RL, < 13DU (RM) high 1UNKNOWN, INFORMATION NOT AVAILABLE (UNK) moderate 7WATER BODIES (WAT) none 9

PART 4: POTENTIAL DRI‐RELATED THREATSCURRENT LAND USE THREAT TO CORRIDORS GRID VALUEDRI PRESENT high 1DRI ABSENT low 9

PART 5: POTENTIAL SLR‐RELATED THREATSSLR MODEL DESIGNATION THREAT TO CORRIDORS GRID VALUEFLOODED 0M SLR none 9FLOODED 1M SLR high 1FLOODED 2M SLR moderate 5FLOODED 3M SLR low 7ABOVE 3M very low 9

Table 1

mod-high



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Map 5



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As Map 5 and Table 3 show, current-land-use-related threats to corridors in southwest Florida are, for the moment, minimal. A few potentially significant threats to IHN-contributed portions of the Moderate Connectivity Model appear in Manatee, Sarasota, and Hillsborough Counties, while small flecks of red dot other portions of the model (e.g., DeSoto County). The ModCon buffer is somewhat more affected by current land uses, with notable pink areas appearing along the Lake Wales Ridge in Highlands County, between Myakka State Forest and the larger Myakka Complex, and around Corkscrew Swamp.

However, it should be pointed out that the Moderate Con-nectivity Model sought to avoid intensive land uses in the first place (see Hoctor and Noss 2010), so for the most part the two should be mutually exclusive (except where there are potentially unavoidable bottlenecks in corridors constrained but not cur-rently cut off by such existing intensive land uses). The current land-use-related threats assessment therefore serves primarily to confirm that intact wildlife corridors (and viable unprotected core habitat) do exist in the region, at least so far as current land use is concerned.

II. Potential ownership-related threats. Ownership fragmenta-tion (a.k.a. parcel fragmentation) is another potential impedi-ment to corridor function, although the degree of fragmentation required to inhibit wildlife movement is not well defined. For this analysis, a 2009 tax parcel dataset provided by UF’s Geo-Plan Center (originally acquired from county tax appraisers) was sorted into two classes: parcels of 100 or more acres and parcels

of less than 100 acres. Only the latter were considered a risk to corridors, represented again by the Moderate Connectivity Model.

For expediency, it was also assumed that each parcel represent-ed a unique owner; while this was probably not always true, the decision reflected practical concerns along with an assumption that, ownership notwithstanding, small parcels are an inherently greater risk to corridor implementation than large ones. Par-cels of less than 100 acres in the Moderate Connectivity Model appear in red (pink in the buffer area) in Map 6; larger parcels in ModCon appear in dark green (light green in the buffer area). Parcel data were unavailable for portions of Highlands County.

Map 6 and Table 4 make clear that ownership-related threats are a matter of concern for the region’s wildlife corridors. Fully 20% of the Moderate Connectivity Model is subject to parcel fragmentation, and nearly 35% of the ModCon buffer is exposed to this potential threat. Ownership-related threats are particu-larly noteworthy in the lower Peace River valley (DeSoto County), in corridors linking the Highlands Hammock State Park with Avon Park Air Force Range, and in many parts of the IHN, especially in Hardee County.

Large areas of red and pink also appear south of Corkscrew Swamp. Although these affect a block of habitat in northern Golden Gate Estates, they leave the Camp Keais Strand corridor

CLC Land Uses Considered Intensive for RA Assessment of Current-Land-Use-Related-ThreatsCLC LC NUMBER AND LC NAME ACRES182136 - Community rec. facilities 11,649 1822 - High Intensity Urban 60,554 18221 - Residential, Med. Density - 2-5 Dwelling Units/AC 1,291,209 18222 - Residential, High Density > 5 Dwelling Units/AC 659,133 18223 - Commercial & Services 370,380 18224 - Industrial 102,537 18225 - Institutional 166,901 1840 - Transportation 140,851 1841 - Roads 148,269 1842 - Rails 13,487 1850 - Communication 4,259 1860 - Utilities 113,851 9900 - Developed 144,196 Table 2

RA: Potential Current-Land-Use-Related Threats to Wildlife CorridorsCATEGORY ACRES

In ModCon - Low Cor. Suitability 23,818 In ModCon - Other Cor. Suitability 2,060,196

ModCon Buffer - Low Cor. Suitability 75,437 ModCon Buffer - Other Cor. Suitability 1,100,064

Table 3

RA: Potential Ownership-Related Threats to Wildlife CorridorsCATEGORY ACRES

In ModCon - 1 - Parcels < 100 Acres 421,307 In ModCon - 5 - No Parcel Data 140,413

In ModCon - 9 - Parcels >= 100 Acres 1,522,294 ModCon Buffer - 1 - Parcels < 100 Acres 410,281

ModCon Buffer - 5 - No Parcel Data 66,369 ModCon Buffer - 9 - Parcels >= 100 Acres 698,851

Table 4



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Map 6



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between Corkscrew and Big Cypress intact. To the Swamp’s north, however, ownership fragmentation within the corridor leading to Webb-Babcock may threaten connectivity between the two. In sum, while ownership fragmentation does not always signal a present-day impediment to wildlife corridors, the potential exists for it to substantially impair the region’s func-tional connectivity in the future. III. Potential future-land-use-related threats. As stated earlier, intensive land uses, especially commercial and high-density-residential development, inhibit corridor function, creating a potentially untraversable barrier for many species. To identify areas where such land uses might soon impact corridors, we compared a statewide future-land-use (FLU) dataset provided by GeoPlan (originally developed by the Florida Department of Community Affairs and the state’s Regional Planning Councils) with the Moderate Connectivity Model. This statewide future-land-use map is a general representation of the future-land-use maps included in the comprehensive plans of each county within the study area.

The future-land-use dataset was sorted according the categories shown in Part 3 of Table 1. This scheme differs from that used to sort current-land-use-related threats (see Table 2) for two rea-sons. First, the input datasets differed, and, second, a gradient-like distribution of threat levels was desired for this analysis, as opposed to the binary system used for the current-land-use analysis. Given the way the Moderate Connectivity Model was identified to avoid existing intensive land uses, we considered future land use a more important consideration for corridor pro-tection than current land use, and therefore developed a more specific model.

The FLU dataset was thus sorted into six classes, reflecting po-tential hazard levels ranging from “no threat” (e.g., agriculture, conservation, recreation, water) to “high threat” (e.g., com-mercial, mixed use, medium and high density residential) with four intermediate values (including government uses and low density residential). The industrial, extractive, transportation category was not assigned the highest threat level value because

it includes the region’s phosphate-mining areas, which were not thought to constitute a high corridor threat due to the potential for mining areas to be restored into areas potentially suitable for facilitating wildlife habitat and connectivity. As usual, the sorted input dataset was combined with the Moderate Connectivity Model, yielding Table 5 and Map 7.

The table shows that the majority of ModCon and ModCon buffer acreage is relatively safe from future-land-use-related threats. The map, on the other hand, reveals the potentially strategic nature of several FLU-related blockages. The corridor linking the Webb-Babcock and Myakka conservation areas, for example, is fragmented by potential future intensive land uses along the eastern side of the lower Peace River in southwestern DeSoto County. Similarly, FLU poses a risk to the connection between the northern Peace River valley and the Green Swamp. Further south, FLU may further constrict the crucial bottleneck along the Caloosahatchee River (near the Glades-Hendry County line) and affect the Corkscrew Swamp to Webb-Babcock corridor. In quantitative terms, then, future-land-use-related threats to regional corridors appear less significant, but in spatial terms, their potential severity is more evident.

RA: Potential Future-Land-Use-Related Threats to Wildlife CorridorsCATEGORY ACRES

In ModCon - Threat Level 1 116,392 In ModCon - Threat Level 2 114,942 In ModCon - Threat Level 3 76,284 In ModCon - Threat Level 5 44,705 In ModCon - Threat Level 7 4,592 In ModCon - Threat Level 9 1,727,098

ModCon Buffer - Threat Level 1 143,030 ModCon Buffer - Threat Level 2 108,332 ModCon Buffer - Threat Level 3 6,186 ModCon Buffer - Threat Level 5 108,736 ModCon Buffer - Threat Level 7 2,493 ModCon Buffer - Threat Level 9 806,724

Table 5



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Map 7



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IV. Potential DRI-related threats. Like the FLU analysis just described, the analysis of corridor threats potentially arising from developments of regional impact (DRIs) identifies potential pending intensifications in land use, which in many cases will involve conversion from natural or agricultural land uses to com-mercial or residential development.1 Although the future-land-use analysis already captures most of these potential changes, the DRI analysis was included because it ensures that the RA takes into account the potential threats posed by these regula-tor-approved, large-scale developments.

As shown by Table 1, the DRI dataset was sorted into threat levels using a binary system: DRIs were considered a potentially high threat and all other areas no threat. Combining this sorted dataset with the Moderate Connectivity Model resulted in Map 8, which is summarized by Table 6.

The situation described by the table and map is not unlike that identified by the FLU analysis. In quantitative terms, DRIs would

1 However, this is not always the case, with many DRIs in the IHN being extrac-tive DRIs. It is important to point out that our analysis does not differentiate between residential, commercial, mining, or other types of DRIs. Nor do we dif-ferentiate between DRIs that were approved many years ago versus those more recently approved. In addition, DRIs can include some designated protected areas within the boundaries of the proposed DRI. A more detailed treatment of DRIs is therefore a recommended next step in areas shown by this analysis to be impacted or even fragmented by DRIs.

seem to pose only a low threat to corridors in the region. But the map again tells a more complete story, revealing several potentially significant DRI impacts, especially between the My-akka complex and the Peace River and along the Glades-Hendry County line and Caloosahatchee River. DRIs also pose a risk to connectivity in central Highlands County, where a DRI appears to fragment the narrow Josephine Creek corridor leading northeast toward Avon Park Range. The almost complete overlap of the Integrated Habitat Network portion of the Moderate Connectiv-ity model is due to the phosphate mining DRIs in the Peace River valley in Polk, Hardee, and DeSoto counties (see Footnote 1).

RA: Potential DRI-Related Threats to Wildlife CorridorsCATEGORY ACRES

In ModCon - DRI 166,787 In ModCon - No DRI 1,917,226

ModCon Buffer - DRI 45,251 ModCon Buffer - No DRI 1,130,250

Table 6



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Map 8



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V. Potential sea-level-rise-related threats. The last individual analysis contrasts with the others in that it evaluates a threat to corridors not driven by land use. However, for many species, widened rivers or newly submerged lands may hinder movement to an equal or greater extent than would intensive development.

A sea-level-rise (SLR) model developed by FNAI (from a digital elevation model provided by FWC) was used for the analysis of potential sea-level-rise-related threats. As shown by Table 1, this dataset identifies areas which would potentially be submerged by one, two, and three meter rises in sea level. Given that a one meter rise is more likely than a two, and a two more likely than a three (at least in the near term), the SLR dataset was sorted such that areas subject to a one meter rise were labeled high risk, those subject to a two meter rise moderate risk, and those sub-ject to a three meter rise low risk. This reclassified dataset was then combined with the Moderate Connectivity Model, yielding Table 7 and Map 9.

The table and map point to another case of localized but potentially significant impediments to wildlife corridors. Only a small percentage of ModCon and ModCon buffer area will be submerged by any more-likely level of SLR. As would be expected, the largest swaths of at-risk acreage lie immediately along the coast, whereas (owing largely to coastal development)

most existing wildlife corridors lie inland. However, where low elevations reach inland, corridor constriction and severance become potential issues. Notice, for example, the strips of red and orange lining the Peace River where it bisects the corridor joining the Webb-Babcock and Myakka conservation complexes (see Map Enlargement 1). In the low-lying Caloosahatchee River valley, potential SLR generates bands of red, yellow, and orange well inland, indicating threats to both the Okaloacoochee Slough to Fisheating Creek corridor and the Corkscrew Swamp to Webb-Babcock corridor. While not extensive in area terms, SLR-related threats thus pose a risk to at least three regional corridors (not to mention its potential inundation of large portions of the con-servation lands themselves--e.g., Big Cypress National Preserve).

RA: Potential Sea-Level-Rise-Related Threats to Wildlife CorridorsCATEGORY ACRES

In ModCon - Threat Level 1 3,875 In ModCon - Threat Level 5 32,808 In ModCon - Threat Level 7 32,355 In ModCon - Threat Level 9 2,014,971

ModCon Buffer - Threat Level 1 12,054 ModCon Buffer - Threat Level 5 22,924 ModCon Buffer - Threat Level 7 9,868 ModCon Buffer - Threat Level 9 1,128,740

Table 7

Map Enlargement 1



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Map 9



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Synthesis of Potential Threats to Wildlife Corridors

I. Process. No one ideal method was identified for synthesizing the five individual analyses; a complete picture of aggregate corridor threats probably requires two perspectives. The general issue here is whether a synthesis should represent at each Mod-Con and ModCon buffer location an average of individual threats or a maximum threat level. An average would identify areas subject to more than one category of high-level threats, but would not highlight areas subject to an intense threat from only one source. A maximum-threat combination, on the other hand, would identify any areas subject to any threat, but in so doing would also fail to communicate the presence of multiple threats. It was therefore decided that both average-threat and maxi-mum-threat syntheses would be performed, since both convey different information and are complementary to one another.

Table 8 shows how these combinations were achieved. In the average-threat synthesis, the five individual analyses were simply combined so that each contributed 20%. Thus a location where four individual analyses had contributed a nine and the other a one would be assigned a 7.4. These average values were not classified (i.e., they were not sorted into discrete categories); they were simply left in their original distribution, represented spatially by Map 10 and quantitatively by Tables 9 and 10.

The maximum-threat synthesis--“Synthesis: Minimum Corridor Suitability (Maximum Threat)”--displays at each location the highest threat level from any of the five individual analyses. So, to a location where four inputs contributed a nine and the other

a one, the maximum-threat synthesis would assign a one (Map 11), since throughout the individual analyses lower values were used to indicate greater potential threats (see Table 1).

II. Results. As would be expected, the two synthesis maps contrast noticeably. The Maximum Threat from Any Input map (Map 11) is more extreme in its representation of potential threats, showing red in many areas colored only yellow by the Inputs Averaged map (Map 10), which offers a more moderated, nuanced view.

Looking more closely at the Inputs Averaged map, it is evident that several corridors face multiple potential threats. First, swaths of yellow and orange bisect the Myakka to Webb-Bab-cock corridors in the lower Peace River valley. Parcel-, future-land-use-, and sea-level-rise-related threats all contribute to this result. Second, the often-mentioned bottleneck along the Glades-Hendry County line and Caloosahatchee River faces multiple threats; these relate to parcel fragmentation, FLU, SLR, and DRIs. Third, portions of the Highlands Hammock to Avon Park Range corridor appear in yellow, especially along U.S. Highways 27 and 700. Parcel-, FLU-, DRI-, and even CLU-related threats contribute to this result. Fourth, the Corkscrew to Webb-Babcock corridors are constricted, primarily by parcel- and FLU-related threats. Finally, almost none of the IHN appears in dark-green, and its Polk and Hillsborough networks appear mostly in yellow.

Table 8

SYNTHESIS: AVERAGEGRID KEY WEIGHT OUTPUT OPERATION OUTPUT OPERATION OUTPUTReclass_flu02 POTENTIAL FLU THREATS: 6 CLASS 0.2fwcdemslr_rec POTENTIAL SLR THREATS 0.2par_reg_951 POTENTIAL OWNERSHIP‐RELATED THREATS 0.2clu_5acup_19 POTENTIAL CURRENT‐LAND‐USE‐RELATED THREATS 0.2DRI_10q3_19 POTENTIAL DRI‐RELATED THREATS 0.2

SYNTHESIS: AVERAGE (GRADIENT)GRID KEY WEIGHT OUTPUT OPERATION OUTPUT OPERATION OUTPUTReclass_flu02 POTENTIAL FLU THREATS: 6 CLASS 0.2fwcdemslr_rec POTENTIAL SLR THREATS 0.2par_reg_951 POTENTIAL OWNERSHIP‐RELATED THREATS 0.2clu_5acup_19 POTENTIAL CURRENT‐LAND‐USE‐RELATED THREATS 0.2DRI_10q3_19 POTENTIAL DRI‐RELATED THREATS 0.2

SYNTHESIS: MINIMUM CORRIDOR SUITABILITY (MAXIMUM THREAT)GRID KEY OPERATION OUTPUT OPERATION OUTPUTReclass_flu02 POTENTIAL FLU THREATS: 6 CLASSfwcdemslr_rec POTENTIAL SLR THREATSpar_reg_951 POTENTIAL OWNERSHIP‐RELATED THREATSclu_5acu_p_19 POTENTIAL CURRENT‐LAND‐USE‐RELATED THREATSDRI_10q3_19 POTENTIAL DRI‐RELATED THREATS

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Map 10

9: Low Threat

1: High Threat

9: Low Threat

1: High Threat

The Center for Landscape Conservation Planning, University of Florida

Rapid Assessment of Corridor Threats, March 2011 Cooperative Conservation Blueprint Pilot

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Florida Natural Areas Inventory

In quantitative terms (see Tables 9 and 10), only modest por-tions of the Moderate Connectivity Model (2%) and ModCon buffer area (6%) are subject to a level-five or higher potential threat in the Inputs Averaged synthesis. However, because the values summarized by Tables 9 and 10 are averages of five inputs, any value below 9 indicates the presence of some po-tential threat, and any value below 7.4 indicates the presence of multiple potential threats. (Some values between 7.3 and 9 may also indicate multiple threats.) And, while 2% and 6% are not overwhelming proportions, as described above, many potential threats are strategically located.

On the other hand, the Inputs Averaged synthesis identifies little acreage subject to top-tier threats from all or most input analyses (i.e., it is not overwhelming orange and red). So while the Inputs Averaged synthesis points to several strategic corridor threats, the relative lack of red and orange in those areas (and in general) suggests that few wildlife corridors in the region face an insurmountable combination of potential threats.

The Maximum Threat synthesis, by contrast, identifies and displays the highest threat value contributed by any of the five individual threat analyses. Not surprisingly, this synthesis cat-egorizes considerable acreage as highly threatened, identifying nearly 29% of ModCon and more than 41% of ModCon Buffer as vulnerable to tier-one threats (Table 11, Charts 1 and 2). Con-versely, only 61% of ModCon and 47% of ModCon buffer face no threat based on this synthesis.

The Maximum Threat map (Map 11) is even more telling, reveal-ing hazards of one kind or another in all corridors (and in most unprotected core habitat areas). Corridors with particularly extreme colorations include all those extending eastward from Myakka; those linking Webb-Babcock and Corkscrew; the con-nection between Okaloacoochee Slough and Fisheating Creek; those between Highlands Hammock and Avon Park Range; and most of the IHN.

Table 9

RA Synthesis: Inputs Averaged (in ModCon)AVERAGE ACRES PERCENTAGE

1.0 0.9 0.000%1.8 115.2 0.006%2.0 2.0 0.000%2.2 45.8 0.002%2.4 14.0 0.001%2.6 823.7 0.040%2.8 409.0 0.020%3.0 90.3 0.004%3.4 2,971.6 0.143%3.6 241.7 0.012%3.8 1,261.6 0.061%4.0 334.9 0.016%4.2 8,928.4 0.428%4.4 6,686.7 0.321%4.6 6,306.4 0.303%5.0 8,969.5 0.430%5.2 3,326.1 0.160%5.4 3,077.2 0.148%5.6 3,215.1 0.154%5.8 79,553.1 3.817%6.0 76,764.3 3.683%6.2 54,077.8 2.595%6.6 23,357.2 1.121%6.8 3,466.0 0.166%7.0 8,790.5 0.422%7.2 2,477.2 0.119%7.4 316,230.9 15.174%7.6 18,005.1 0.864%7.8 16,302.9 0.782%8.2 157,231.9 7.545%8.6 17,128.7 0.822%9.0 1,263,803.1 60.643%

TOTALS 2,084,008.9 100.000%

RA Synthesis: Inputs Averaged (ModCon Buffer)AVERAGE ACRES PERCENTAGE

1.0 246.4 0.021%1.8 587.8 0.050%2.0 6.0 0.001%2.2 238.4 0.020%2.4 11.8 0.001%2.6 3,564.3 0.304%2.8 2,446.8 0.209%3.0 28.2 0.002%3.4 3,538.0 0.302%3.6 1,225.8 0.105%3.8 1,928.8 0.164%4.0 597.6 0.051%4.2 32,825.8 2.799%4.4 12,676.4 1.081%4.6 1,214.7 0.104%5.0 9,557.5 0.815%5.2 4,121.6 0.351%5.4 1,674.6 0.143%5.6 2,597.8 0.221%5.8 81,716.1 6.967%6.0 64,818.0 5.526%6.2 3,182.9 0.271%6.6 49,395.1 4.211%6.8 3,440.4 0.293%7.0 1,928.1 0.164%7.2 747.2 0.064%7.4 206,126.4 17.574%7.6 15,642.2 1.334%7.8 2,286.2 0.195%8.2 110,330.9 9.407%8.6 1,946.8 0.166%9.0 552,243.7 47.084%

TOTALS 1,172,892.4 100.000%

Table 10



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Map 11



22

41.1%

1.7%0.2%

9.8%

0.2%

47.1%ModCon Buffer - Threat Level 1

ModCon Buffer - Threat Level 2





Chart 2. Synthesis: Maximum Threat, ModCon Buffer

RA Synthesis: Maximum Threat from Any InputCATEGORY ACRES

In ModCon ‐ Threat Level 1 598,986 In ModCon ‐ Threat Level 2 23,948 In ModCon ‐ Threat Level 3 16,256 In ModCon ‐ Threat Level 5 163,187 In ModCon ‐ Threat Level 7 17,132 In ModCon ‐ Threat Level 9 1,258,110

ModCon Buffer ‐ Threat Level 1 482,233 ModCon Buffer ‐ Threat Level 2 19,830 ModCon Buffer ‐ Threat Level 3 2,273 ModCon Buffer ‐ Threat Level 5 114,365 ModCon Buffer ‐ Threat Level 7 1,947 ModCon Buffer ‐ Threat Level 9 552,244

Table 11

28.8%

1.2%

0.8%

7.9%

0.8%

60.6%

In ModCon - Threat Level 1






28.8%

1.2%

0.8%

7.9%

0.8%

60.6%







Chart 1. Synthesis: Maximum Threat, ModCon



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Conclusions

The Rapid Assessment of Corridor Threats points to three es-sential (and several secondary) conclusions. First, wildlife cor-ridors in southwest Florida face various potential threats. The Maximum Threat synthesis suggests that unless action is taken, one potential threat or another could constrict or fragment all regional corridors. The Average Threat synthesis hints at the problem’s complexity, identifying considerable acreage that is subject to multiple potential threats.

Second, three specific areas stand out as particularly vulnerable to multiple potential threats. These are the corridor/habitat bottleneck along the Glades-Hendry County line, the lower Peace River valley, and the Polk and Hillsborough County portions of the IHN. The potential multi-source nature of these threats is illustrated by the Inputs Averaged map, which highlights overlap-ping corridor threats. The individual analysis maps reveal that

DRIs and future-land-use plans are the principal potential threats in these areas, but parcel fragmentation and sea level rise also play a role. These critical locations--strategic for connectivity and potentially affected by multiple threats--deserve immediate attention from project partners.

Finally, the Rapid Assessment is not intended to be comprehen-sive in nature, but instead can serve as a useful guide for indicat-ing where potential existing and future threats could impact regional wildlife corridors. The areas where potential threats are concentrated are an important starting point for efforts to deter-mine priority areas for this regional wildlife corridor project and for determining the efforts and incentives that will be needed to ensure protection of Southwest Florida’s functional habitat and wildlife corridors.



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Works CitedForman, R. T. 1995. Land mosaics: the ecology of landscapes and regions. Cambridge University Press, Cambridge, United Kingdom.

Noss, R.F., and T.S. Hoctor. 2010. Babcock ranch regional connectivity study. Available from http://conservation.dcp.ufl.edu/Bab-cock%20Ecological%20Connectivity%20Report%202_22_2010%20Final.pdf (accessed December 2010).

Zwick, P. D., and M. H. Carr. 2006. Florida 2060: A population distribution scenario for the state of Florida. University ofFlorida GeoPlan Center, Gainesville, Florida. Available from http://1000friendsofflorida.org/PUBS/2060/Florida-2060-Report-Final.pdf (accessed March 2011).

Documents

Rapid Assessment of Threats to Wildlife Corridors in ...conservation.dcp.ufl.edu/RA_Report_March 2011.pdf · The Rapid Assessment of Threats to Wildlife Corridors in Southwest Florida,