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Assessing critical habitat and threats to endangered Stickleback Species pairs on the forested land base
Rosenfeld, Jordan S.
One of the key biodiversity goals and responsibilities of the province of B.C., private landowners, and the forest industry is to ensure the persistence of globally endangered species on the forested landbase. B.C. is legally committed to recovery planning for endangered species under the Species At Risk Act, which requires identifying critical habitat for species at risk, as well as non-habitat related threats to species persistence and how to manage them. Recovery planning is a critical step in resource planning if B.C. is to fulfill its commitment to maintain endangered species on the forested land base. Stickleback species pairs are nationally and globally red listed and contribute uniquely to provincial and global biodiversity. In addition to their intrinsic biodiversity value they have supported some of the most advanced research in evolution and genetics since Darwins' finches (e.g. Rundle et al. 2000; Peichel et al. 2001; Colosimo et al. 2005; Keneddy 2005). Stickleback species pairs are globally unique in that a benthic and limnetic species have recently evolved and differentiated in the same lakes, with the benthic species feeding on benthos in the littoral zone and the limnetic feeding on zooplankton in the pelagic zone. Current status of stickleback species pairs in B.C. is not encouraging (Foster 2003; Wood 2003). Four pairs have been identified in six different lakes (Foster et al. 2003). One of the pairs (Hadley Lake) has been extirpated due to introduction of alien fish (Ictalurus catfish; Hatfield 2001), and another species pair (Enos Lake) has collapsed into a hybrid swarm for unknown reasons (circumstantial evidence implicates habitat change associated with watershed development or crayfish introduction; Boughman 2001; Gow et al. 2006; Taylor et al. 2006). Only two of four original species pairs are extant in the four remaining lakes on Texada Island, three of which are on public or private forested land subject to industrial logging. The importance of proper habitat and watershed management in these forested watersheds is heightened because they represent 75% of the remaining global distribution of extant species pairs. Given that half of the original species pairs have become extinct over a relatively short period, the remaining species are likely to suffer the same fate unless threats to their persistence are properly identified and managed. Establishing critical habitat and identifying and minimizing threats to species persistence is a priority commitment for provincial agencies responsible for management of endangered species and their habitats on provincial forested lands (i.e. Ministries of Environment and Forests). Although stickleback species pairs have been subject to enormous research focused on their evolutionary ecology and genetics, little is known about their ecological requirements or habitat associations. We propose targeted research to identify both critical habitat (Rosenfeld and Hatfield 2006) and the priority habitat and non-habitat related threats to species persistence (e.g. forestry impacts, exotic species) on the forested land base, in support of prioritizing management actions to minimize these threats. Specifically, we will work towards identifying critical habitat through a combination of 1) habitat identification and mapping in species pairs lakes, 2) assessment of the habitat attributes that are necessary for species persistence based on the distribution and productivity of habitats in species pairs lakes relative to single-species stickleback lakes, 3) assessment of seasonal fluctuations in habitat availability associated with natural and human-modified changes in water levels that affect habitat availability (e.g. littoral macrophyte beds vs. pelagic habitat), and 4) habitat-explicit Population Viability Analysis (PVA). We will also determine key demographic parameters for sticklebacks in species pair lakes on the forested land base, such as better estimates of benthic ...
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Effects of Alien Crayfish... (Report)

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