320 



Interior West — Our Living Resmirce.'! 



Table 2. Selected sensitive, rare, and endangered plants of the sky islands. 



Tabic 3. Various threatened, 

 endangered, and candidate 

 species ■ 



Chaenaxis. More than 75 reptile species inhab- 

 it the sky islands, one of the most diverse her- 

 petological regions in Noilh America with sev- 

 eral endemic races. 



About 265 bird species occur within the sky 

 island complex, including valley and riparian 

 species. About .'^O are of subtropical origin and 

 have their northern limits within the sky island 

 complex. The sky islands are the most diverse 

 U.S. area for mammals: some 90 native mam- 



'This list is incomplete because of revisions since publication in 1988 Only animals inhabiting sky islands within or above 

 the oak-pine woodlands are included. Some wetland species have not been included The species must have been on fed- 

 eral lists. Vanous — more than two sky-island ecosystems; T — threatened; E — endangered; C — candidate in Arizona 

 or New Mexico; ( ) — listing by Arizona Fish and Game only; federal status not yet determined. 



mals inhabit the area frotn the chaparral com- 

 munity to higher elevations; at least 6 are 

 endemic subspecies. 



Trends and Management 



Researchers have begun measuring biologi- 

 cal trends in six major categories concerning 

 inventory, monitoring, preservation, and 

 restoration that are most pertinent to sky island 

 forested ecosystems. A discussion of these cat- 

 egories follows. 



Endemics and Insular Species 



With new investigative techniques, there has 

 been growing respect for the genetic diversity of 

 this area, especially late-Cenozoic and 

 Pleistocene relict faunal populations (see exam- 

 ples. Tables 2, 3). For instance, recent genetic 

 analyses on the Mt. Graham red squirrel 

 (Tamasciuris hudsonicus i>rahcimeiisis) and the 

 lemon lily (Lillium panyi) showed that both 

 populations are more highly divergent from 

 closely related populations than previously 

 thought. Increasingly, however, local and insu- 

 lar species have hybridized with introduced 

 races and species; hybridization is particularly 

 evident among fish (e.g.. hybrids of the Apache 

 trout. Oncorhynchus apache, with the rainbow 

 trout. O. mykiss), but can also be found among 

 white-tail deer (Odocoileus virginiamis versus 

 hemionus). pronghorn (Antiiocapra americana 

 versus mexicana). turkeys (Meleagris merriami 

 versus mexicana), and bighorn sheep (Ovis 

 mexicana versus nelsoni). 



Selected rare, unique, threatened, and 

 endangered species and subspecies whose criti- 

 cal habitat includes the sky islands are listed in 

 Tables 2 and 3. Figure 3 compares the Coronado 

 National Forest to other forests. The number of 

 sensitive plant and animal species from the sky 

 island ecoregion has increased over the last 20 

 years. (Sensitive means that the population's 

 viability is of concern and requires monitoring 

 or active protection.) The increase is. in part, the 

 product of more detailed knowledge. For 

 instance, a recent review of Erigeron pringlei 

 split this fleabane into four species, creating a 

 new endemic, E. heliographis. on the Pinalenos. 

 Nevertheless, the Coronado Forest reports 56 

 sensitive plants, among the largest number 

 reported from any national forest, including 1 

 on the federal endangered list and 3 candidate 

 species. McLaughlin (University of Arizona, 

 unpublished data) suggested that the local extir- 

 pation of six plant species in the last century 

 was related to either global warming, habitat 

 alteration, or both. 



Seven insects are listed by the Coronado 

 National Forest as species of concern (U.S. 

 Forest Service, unpublished memo). About 12 



