Recovery Plan for the Northern Spotted Owl - DRAFT

Riparian Ecosystemssilvicultural practices in very young (less than 40 years) stands that are aimedat producing habitat structure for owls will not provide the branch structureassociated with murrelet nest sites. Ruggiero et al. (1988) stated that asmanagement becomes more tightly directed at a single species, it is less likelyto provide for other species. Baker and Schonewald-Cox (1986) concluded that"Incorrectly assuming that other species are receiving protection as a result ofthe protection of Ian indicator] can result in the inadvertent loss of those otherspecies."These cautions on the use of indicators were used in several ways in thedevelopment of the recovery plan. First, in developing the overall strategy forspotted owl recovery, the Recovery Team evaluated the overlap between possiblespotted owl management areas and the ranges and locations of otherspecies that were judged to be priorities. Second, in developing recommendationsfor management practices of DCAs, the Recovery Team attempted to lookbeyond the habitat attributes associated with spotted owls. Wherever possible,the Recovery Team used the structure and functioning of older forests as abenchmark for recommendations on management activities. This insured thatthose activities would help provide habitat for other species and not focus sospecifically on spotted owls that other species were inadvertently harmed.Riparian areas are among the most ecologically important components of forestlandscapes. There are several definitions for riparian areas, but basically theyare areas where soils contain free or unbound water and are recognized byunique vegetation types adjacent to lakes, streams, rivers, ponds, marshes,seeps, or bogs. They form boundaries between different ecosystems andprovide connectivity for interchange and dispersal for plants and animals.Spotted owls often are associated with riparian areas within their home ranges.Forsman (1976) first noted this relationship; he reported that all but threenests he located were within 425 yards of water. Later, Forsman et al. (1984)noted the same relationship for a larger sample of nest sites. Using radiotelemetry,Solis (1983) and Solis and Gutierrez (1990) also reported thatroosting and foraging sites were more likely to be found on the lower thirds ofslopes (i.e., near streams within their home ranges) than elsewhere. Finally,Blakesley et al. (In press) report a similar relationship in northwestern California.Their study analyzed all roost and nest sites used by an entire populationof owls over a 5-year period. Thus, analysis of individual selection and populationselection have noted an association of spotted owls with riparian areas.The association of spotted owls with streams and associated vegetation is notwell understood, but there may be several reasons for the observed relationship:1) riparian areas usually are cooler, which may facilitate thermoregulationin the owls (Barrows and Barrows 1978; Barrows 1981); 2) riparian areasin the Pacific Northwest often are more productive areas in terms of treegrowth, and this may promote more rapid development of suitable nest sites; 3)riparian areas usually support a more diverse biota than adjacent areas,resulting in the structural diversity that is characteristic of spotted owl habitat;and 4) riparian systems are more floristically rich and consequently maysupport higher numbers and abundance of prey species.337