Ecological Archives A021-135-A3

Angela L. Strecker, Julian D. Olden, Joanna B. Whittier, and Craig P. Paukert. 2011. Defining conservation priorities for freshwater fishes according to taxonomic, functional, and phylogenetic diversity. Ecological Applications 21:3002–3013.

Appendix C. Methodological details of Zonation implementation.

We used the core-area implementation of Zonation to identify locations where a single species has an important occurrence, although it may be an otherwise species-poor location (Moilanen et al. 2009). In this implementation, species are not substitutable for each other, placing greater importance on species identity. To incorporate species-specific connectivity requirements, we first estimated a home range for each species with the regression equation developed by Minns (1995), which relates the range size of riverine fish to maximum body size:

loge H = -2.41 + 1.52 × logeL

where H = home range (m²) and L = body length (mm). This home range is then rescaled to α, the species-specific scale of landscape usage (i.e., maximum dispersal distance: Moilanen and Kujala 2008).

Each species has a specific response to fragmentation of the landscape and loss of habitat, and therefore, has specific connectivity requirements. For example, a species that is highly sensitive to fragmentation would likely need a larger conservation area compared to a species that is less sensitive to fragmentation. These values were derived from studies by Fagan et al. (2002, 2005), who developed scale-area slopes for historical and contemporary populations of native fishes. Scale-area slope is a scale-independent quantitative measure of spatial rarity, where large values indicate fragmented distributions whose occurrences were sparsely distributed over a large region, and small values represent species with more compact distributions (Fagan et al. 2002). We assumed that an increase in the scale-area slope from historic to contemporary periods is indicative of increasing sensitivity to habitat loss and fragmentation. This value was then subtracted from 1 to conform to the needs of the program. Non-native fish were considered to be insensitive to habitat fragmentation, as most are moved both intentionally and unintentionally by humans, thus dissolving barriers to movement (Rahel 2007). Additionally, we determined that upstream connectivity is likely slightly more limited than downstream connectivity for fishes (Olden et al. 2001), and appropriately changed sensitivity to fragmentation values.


LITERATURE CITED

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Fagan, W. F., C. M. Kennedy, and P. J. Unmack. 2005. Quantifying rarity, losses, and risks for native fishes of the lower Colorado River Basin: implications for conservation listing. Conservation Biology 19:1872–1882.

Fagan, W. F., P. J. Unmack, C. Burgess, and W. L. Minckley. 2002. Rarity, fragmentation, and extinction risk in desert fishes. Ecology 83:3250–3256.

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Minns, C. K. 1995. Allometry of home range size in lake and river fishes. Canadian Journal of Fisheries and Aquatic Sciences 52:1499–1508.

Moilanen, A., and H. Kujala. 2008. The Zonation conservation planning framework and software v.2.0: user manual. http://www.helsinki.fi/bioscience/consplan/

Moilanen, A., H. Kujala, and J. Leathwick. 2009. The Zonation framework and software for conservation prioritization. Pages 196-210 in A. Moilanen, K. A. Wilson, and H. P. Possingham, editors. Spatial conservation prioritization: quantitative methods and computational tools. Oxford University Press, Oxford, UK.

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Olden, J. D., D. A. Jackson, and P. R. Peres-Neto. 2001. Spatial isolation and fish communities in drainage lakes. Oecologia 127:572–585.

Rahel, F. J. 2007. Biogeographic barriers, connectivity and homogenization of freshwater faunas: it's a small world after all. Freshwater Biology 52:696–710.

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