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California Clapper Rail cont. Marsh size and habitat quality, considered together, determine the maximum number of rails which can be supported in a particular marsh. It is important to consider habitat quality prior to starting a restoration project, since parcels of low quality habitat may not be able to support a viable rail population. This is because rails call to each other to contact one another, to advertise breeding status, and to defend territories. If a rail cannot hear another rail because they are too far apart, it may not find a mate or breed. A population of many unmated rails will not sustain itself. Location of marshes with respect to one another should also be taken into consideration when planning restoration. Marshes to be managed for breeding clapper rails should be in close proximity to each other to facilitate dispersal without risk of excessive predation. Minimally, marsh corridors (low-quality, narrow marsh habitats not used by rails for breeding), should be available between the primary breeding marshes to provide cover for migrating rails. Size of buffer areas or transitional habitat (area between the marsh and uplands) is important because outside influences from the upland area may have devastating effects in the marsh. The larger the buffer, the less severe or direct the impacts will be. For instance, one of the reasons the non-native red fox is able to have a large impact on rail populations is because there is no buffer area between the uplands and the marsh. Most remaining marshes have levees on at least two sides and the foxes use the levees to reach the marsh. The shape of marshes also determines ease of access for foxes. The narrower the marsh, the easier it is for foxes (and other terrestrial predators) to gain access to the entire marsh. Historically, marshes were very wide, with ample transition zones. Likely, terrestrial predators limited their activities to the edges of the marshes and wildlife in the interior of the marsh was safe from this type of predation. The presence of intricate networks of tidal channels in marshes is one of the |
Last updated:
May 22, 2008
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