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and Brock 2006). The legislature also mandated public land protection agencies to focus on using
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alternatives to fee simple acquisition. Since 2000, FF has protected more than 1.3 million acres
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of water resources, environmentally sensitive lands, and parks (Department of Environmental
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Protection [DEP] 2016). Many of these areas have been protected through less-than-fee
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arrangements, involving purchase of conservation easements. Conservation easements allow
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lands to stay in private ownership but legally restrict what activities can occur on the land. At the
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64 • MICHAEL I. VOLK ET AL.
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same time, the land stays on the local tax rolls and under private management. Figure 2.2 shows
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conservation lands in Florida classified by date of protection based on the Florida Natural Areas
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Inventory Florida Conservation Lands dataset. This data includes both public and private lands
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that are either protected primarily for conservation or where conservation is an important activity
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(e.g., various military installations across Florida).
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Figure 2.2. Florida conservation lands and date of protection. Data Source: Florida Natural Areas Inventory
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Florida Conservation Lands (Florida Natural Areas Inventory 2016)
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Today Florida has a substantial acreage of its lands and waters in some kind of conservation
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designation. Combined local, state, and federal conservation holdings equate to 29.4% of the
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state, with 9,447,419 acres held in fee simple ownership and another 760,400 acres under
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conservation easements (this figure is slightly higher if private conservation lands and lands in
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FLORIDA LAND USE AND LAND COVER CHANGE IN THE PAST 100 YEARS • 65
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private mitigation banks are included). These figures also include lands managed by the
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Department of Defense (e.g., Eglin Air Force Base) for conservation benefits (667,200 acres)
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and land under conservation easements held by the federal Natural Resources Conservation
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Service (121,122 acres). Figure 2.3 shows conservation and managed lands in Florida classified
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by managing entity.
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Figure 2.3. Florida conservation lands and managing entities. Data Source: Florida Natural Areas Inventory
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Florida Conservation Lands (Florida Natural Areas Inventory 2016).
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While Florida’s history of conservation achievement has been impressive, it has not been
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enough to prevent wholesale changes to and conversion of the Florida landscape – and its ecology
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– on a massive scale, and additional conservation land is needed to effectively conserve the still
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significantly, but quickly vanishing, natural resources that are still unprotected.
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66 • MICHAEL I. VOLK ET AL.
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Climate Change Impacts on Land Use and Land Cover To-Date
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It is important to understand how changes in climate are already impacting land cover within the
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state, as an indicator of what types of future changes may occur. Significant shifts in land cover
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are already being seen in both upland and coastal areas as a result of sea level rise, precipitation,
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and temperature change. Some of these are summarized here, though others are undoubtedly
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occurring or have been documented.
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Coastal Land Cover Changes along the Big Bend Coast
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Florida’s Big Bend Coast, which stretches along the Gulf of Mexico from just north of Tampa to
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south of Tallahassee, remains the least developed coastal region in the lower 48 states of the U.S.
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The region’s forests, salt marshes, and near coastal marine environments are legendary for their
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productivity due to a combination of factors including massive fresh water inputs from the
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Suwannee River and several first-magnitude springs. That said, it has certainly not been spared
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from human use, which is intensifying, while it is being rapidly inundated again by rising seas
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(Williams et al. 1999; de Santis et al. 2007; Raabe and Stumpf 2016).
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An understanding of the area’s geography is necessary to understand current changes. Like
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most of Florida, the area is low in elevation and topographically nearly flat; the highest points
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along the coast are the paleodune on Sea Horse Key and nearby Shell Mound, which started as a
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dune but was enhanced by Amerindian engineers more than 1000 years ago — neither of those
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peaks exceeds 20 meters in elevation. The flatness of the coastal region extends far out into the
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Gulf of Mexico.
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Another distinctive characteristic of the Big Bend region relates to the abundant water, both
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fresh and somewhat salty. Tidal amplitudes in the Gulf of Mexico are small, less than half of
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those in the Atlantic. Massive influxes of fresh water keep the near-shore salinities in Gulf water
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at half of “normal” sea water. While all the rivers and spring runs moderate the Gulf’s salinity,
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their waters do not deliver much sediment. Trapped sediments help build land, but the amount
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deposited on coastal areas of the Big Bend is a small fraction of that carried by rivers.
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The natural ecosystems along the Big Bend reflect the impacts of sea salt, as determined by
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centimeters of elevational change and tempered by distance from the coast. As elevation rises
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from the open water of the Gulf one crosses sea grass flats, some of which are exposed at
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especially low tides, mud flats, and oyster bars. Salt marshes are next, often dominated by black
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needle rush (Juncus roemerianus) with saltmarsh cordgrass (Spartina spp.) on the depositional
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banks of meandering tidal streams. At slightly higher elevations, salt marsh shrubs flourish often
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under the dying crowns of the red cedars (Juniperus virginiana) and cabbage palms (Sabal
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palmetto) they replace as sea level rises. Healthy forested islands of cabbage palms and cedars
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surrounded by salt marsh are next at elevations of 50-60 cm where inundation is only by the
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highest of high tides as well as by storm surges, which can be several meters high. Inland and
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slightly uphill from the coastal hammocks of cedar and palms there can be slash pine flatwoods
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FLORIDA LAND USE AND LAND COVER CHANGE IN THE PAST 100 YEARS • 67
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on sandy soils where fires are frequent or, more often, swamp forests referred to as hydric
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hammocks (Vince et al., 1989). These long hydroperiod wetlands can have as many as 25 species
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of canopy trees including several species of ash (Fraxinus spp.), oak (Quercus spp.), and elm
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(Ulmus spp.), with only scattered cabbage palms.
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Big Bend ecosystems have been shaped by humans since they arrived some 14,000 years ago.
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For example, early as well as recent occupants harvested the bountiful shell and bony fish
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(McCarthy 2006). While modern clam farms benefit from new technologies, farming the sea has
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been underway for millennia, as indicated by archeological discoveries of massive fish weirs and
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managed oyster bars. Less than a century ago, pencil slat and brush factories near Cedar Key
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gobbled up thousands of red cedar and cabbage palm trees every month. Up until a few decades
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ago when the furniture mills closed, hardwoods were harvested from the hydric hammocks. To
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this day, stands of slash pine are clear-cut for pulp and saw timber, hunters seek deer, turkeys,
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bear, and other wildlife throughout the region while crabbers, oyster harvesters, and fisherman
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ply the coastal waters and up into the tidal creeks.
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In addition to the direct effects of sea level rise, ecosystems in the Big Bend Region are being
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influenced by the decreasing frequency of the hard freezes that set the northern limits to the
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distributions of many plant species including mangrove trees (Williams et al. 2014). For reasons
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that are not yet clear, no tree species can withstand both high salinity and cold freezes. This
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means that where there are hard freezes, salt marshes predominate, whereas the coasts of warmer
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areas typically support mangrove forests. Black mangrove (Avicennia germinans), the most
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common species of mangrove tree in the region, can withstand super-high salinities but is killed
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by freezing temperatures. The northern limit of black mangrove is currently about halfway up
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the Big Bend Coast, but that limit continues to shift northwards as will be described in more
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detail in the next section. This massive switch from marsh to forest has numerous implications
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for the biota, biogeochemistry, and the effects of storm surges, which are blocked better by dense
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forests than by low-growing herbaceous vegetation.
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The other big change underway along the Big Bend Coast is also related to global change,
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but is driven by Brazilian pepper, an invasive species described earlier in this chapter. Brazilian
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pepper is top-killed by hard freezes but, unlike mangrove trees, re-sprouts afterwards. The fact
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that it tolerates fairly high soil salinities allows it to proliferate where cabbage palms and cedar
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trees are succumbing to salt stress (Ewe and Sternberg 2005). Because it can grow taller than the
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