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36 Creating Habitat Reserves for Migratory Salamanders
- University of California Press
- Chapter
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260 Habitat loss and fragmentation results in the reduction and isolation of amphibian populations (Reh and Seitz, 1990; Gulve, 1994) and the subsequent increased risk of local extinction (Saccheri et al., 1998). While local extinctions are often part of amphibian population dynamics, amphibian populations persist because such extirpations are compensated for by recolonization and the resulting rescue effect (Skelly et al., 1999). However, the fragmentation of amphibian habitats inhibits dispersal and thereby hinders or prevents the rescue effect (Reh and Seitz, 1990; Gulve, 1994). Massachusetts provides a prime example of this conservation challenge and of the need to protect connected habitat complexes for amphibians, especially for migratory salamanders . Massachusetts is the third most densely populated state in the union, with an average of 765 residents per square mile, ten times the national average of 74 residents per square mile (MEOTC, 1998). Massachusetts contains 68,642 lane miles of roads. The largest roadless area is the 3,400 acres (0.07% of the state’s total land area) that surrounds the Quabbin Reservoir in central Massachusetts. This “roadless” area does include limited -access dirt roads. Despite relatively strong state laws protecting wildlife and habitats, populations of ambystomatid salamanders are threatened by the densities of development and roads in Massachusetts . Of the four native ambystomatids in Massachusetts, three are listed by the Massachusetts Division of Fisheries and Wildlife (DFW) as Threatened (marbled salamanders, Ambystoma opacum) or Species of Special Concern (Jefferson salamanders , A. jeffersonianum, and blue-spotted salamanders, A. laterale). Only spotted salamanders (A. maculatum) are considered common. Regulatory measures alone are unlikely to protect rare salamanders from further decline in Massachusetts. Regulations do not recognize the full extent of the habitats on which ambystomatid salamanders depend. Even when breeding habitats are protected by the Massachusetts Wetlands Protection Act and its implementing regulations, these regulations do not apply to upland habitat, nor do they require that upland and wetland habitats remain connected and free of barriers to salamander movement. Although the Massachusetts Endangered Species Act can protect both wetland and upland habitats of rare salamanders, upland habitats between breeding sites are difficult to delineate, and, subsequently, to regulate (Melvin and Roble, 1990). In addition, because state environmental regulations are applied to individual projects as they are proposed , the regulations fail to prevent the cumulative loss of habitat brought on by the gradual encroachment of urban and suburban sprawl on remaining wildlands. An effective strategy for statewide conservation of ambystomatid salamanders involves proactive protection of habitats , rather than solely relying on regulations. The Natural Heritage and Endangered Species Program of the DFW is currently working to identify and map conservation areas for rare herpetofauna, including marbled, Jefferson, and blue-spotted salamanders. To design effective reserves, we need to know the minimum areas necessary to sustain viable populations, as well as the landscape and habitat features that these areas should contain (see Quinn and Scott, this volume). To address these questions, we need information on (1) the minimum viable population size for each species; (2) population density; (3) dispersal distances; and (4) habitat requirements of each species, including the entire array of habitat types used during an annual cycle as well as during a drought cycle (see Lannoo, 1998a). Our project illustrates both a conservation strategy and the information needs of managers attempting to protect amphibian habitats. Initially, the effectiveness of habitat reserves and the process of designing them may be limited by a lack of empirical data to guide our efforts. We have limited information on upland habitat use and dispersal distances of these animals, so designing reserves for ambystomatid salamanders involves working with some degree of uncertainty about the types and extents of critical habitats. However, waiting until we answer all the unknowns will certainly result in continued loss and fragmentation of habitats. Current Legal Protection for Rare Herpetofauna in Massachusetts Conservation laws in Massachusetts have not succeeded in comprehensive protection of connected upland and wetland complexes on which populations of ambystomatid salamanders depend (Melvin and Roble, 1990). Wetland habitats are TH I RTY-S I X Creating Habitat Reserves for Migratory Salamanders SUZANNE C. FOWLE AND SCOTT M. MELVIN HABITAT RESERVES FOR MIGRATORY SALAMANDERS 261 protected from direct impact by the Massachusetts Wetlands Protection Act, which prohibits “short or long-term adverse impacts” to habitats of state-listed, wetland-dependent wildlife (MGL c. 131 s. 40). This protection extends to a 100-foot-wide buffer zone around most jurisdictional wetlands, but it otherwise fails to protect the full extent of uplands...