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F RAY E 0 S A F E T Y NET S .......................................................................................................................................................................,.., gered bird species. According to the team's 1990 report, in order for the plan to result in viable populations of both bird species within the plan- ning area, there must be enough habitat to sup- port 500 to 1,000 breeding pairs in the preserves (the team recommended two such populations for the golden-cheeked warbler). According to their calculations, this would require an HCP with 130,000 acres of preserves (Travis County is 648,000 acres), after taking into account decline in habitat quality due to edge effects, urbaniza- tion and habitat fragmentation. These recommendations were deliberately developed with no reference to the political and economic contexts. In order to follow the rec- ommendations completely, the plan would have required hundreds of millions of dollars and extensive restoration of areas that were signifi- cantly degraded (130,000 acres of intact habitat no longer existed, for example). Instead of try- ing to achieve the goals recommended in the biological advisory team's report (i.e., viable pop- ulations), planners decided to implement the rec- ommendations to the extent possible. Unfortunately, the team's recommendations became a science-based high-water mark that simply was not practical to achieve and served to illustrate the precarious condition of the warbler and vireo. The plan allows take of 55 percent of the black-capped vireo population and up to 71 per- cent of the identified golden-cheeked warbler habitat in the planning area. In the final pre- serve design, the total preserve acreage will be at least 30,428 acres distributed in seven preserve units, if all anticipated funding is realized. In addition, the plan was instrumental in the estab- lishment of Balcones Canyonlands National Wildlife Refuge, where management for signifi- cant numbers of the endangered birds will enhance populations. While the acreage of the preserve and the wildlife refuge captures much of the large, relatively unfragmented habitat patches for the birds, and while habitat management will slow habitat degradation due to public use, the preserve design falls far short of original, biologi- cally based expectations. Indeed, "the current consensus of the wildlife agencies appears to be that... the proposed action could threaten the population viability of the golden-cheeked war- bler in the permit area" (Final HCP, pp. 4-19). Obviously, the 35,000-acre preserve system is much smaller than the 130,000 acres recom- mended by the biological advisory team. In implementing the plan, however, the city of Austin and wildlife agencies may be able to ame- liorate this inadequate acreage by managing habi- tat so that it sustains higher numbers of warblers and vireos. The team's 1990 report, however, specifically addressed habitat management versus acquisition and preservation: "It is thus impossi- ble even to identify all the threats caused by habitat destruction, much less to address these threats by intensive management. Because of this, without preservation of adequate habitat even the most intensive management will eventu- ally fail" (p. 2). The relationship between man- agement and acquisition, however, was not examined in detail by the team, and the ultimate success of some of the management techniques is not guaranteed. Aside from inadequate land acquisition for G