this is also important to conservation. The conserva- 

 tion value of Darwin's finches derives in no small part 

 from the substantial evolutionary differences that sepa- 

 rate these Galapagos Island birds from continental 

 forms. 



Species of Special Concern 



Biologists maintain "Red Books" in which the world's 

 endangered and threatened species in all taxonomic 

 groups are listed. Rates of current habitat destruction 

 are such that these compilations can never be up-to- 

 date — by the time they are compiled and published, 

 many more species are known to be endangered. In 

 addition, such books cannot be more than indicative, 

 given the large proportion of biological species still un- 

 known to science. Many unknown species are un- 

 doubtedly imperiled, but detailed knowledge is re- 

 quired to demonstrate that a species is imperiled. Jared 

 Diamond of the University of California, Los Angeles 

 has suggested that a more scientifically defensible en- 

 deavor would be to publish "Green Books," enumerat- 

 ing those (relatively few) species that are known to be 

 secure. 



Museum scientists generally focus on ecosystem- 

 level conservation but also make important contribu- 

 tions to efforts to conserve particular species. These 

 contributions rest on broad training. Through study of 

 all aspects of natural history, museum scientists com- 

 monly assemble the foundations of ecological and be- 

 havioral information on species of special concern. 

 This information is essential to management of natural 

 populations. Recent Field Museum studies on diets of 

 harpy eagles, abundance and habitats of Chilean 

 shrew-opossums, geographic ranges of New World 

 monkeys, and ecology of Asian flying lizards serve as 

 examples. These contributions can have value to con- 

 servation which transcends management programs fo- 

 cused on single species — individual species such as har- 

 py eagles, spectacled bears, and lion tamarins can serve 

 as "flagships" for conservation efforts, igniting public 

 interest and support. 



Conceptual Studies in Conservation 



Conceptual studies are key to making conservation 

 biology a predictive and powerful science. It is impos- 

 sible to study individually all the areas that need pre- 

 servation, given shortages of money, manpower, and 

 time. By assembling information on general patterns 

 and processes, scientists can make inferences that per- 



Discovered and described by Field Museum zoologist W, H, 

 Osgood during the Marshall Field Chilean Expedition of 1922-23, 

 the Chilean shrew-opossum {Rhyncholestes raphanurus) remained 

 virtually unknown for 60 years. In 1 977, Chilean researchers de- 

 clared it "the rarest mammal in Chile." During an inventory of Parque 

 Nacional Vicente Perez Resales, mammalogist Bruce Patterson 

 found that this form was abundant and occupied a variety of habi- 

 tats, indicating its current status as secure. Photo by b d Patterson 



mit informed conservation decisions in a timely and 

 cost-effective fashion. 



Most predictions of species loss in the wake of tro- 

 pical deforestation are based on an analogy between 

 nature reserves and islands. Like islands, nature pre- 

 serves are often surrounded by inhospitable areas and 

 isolated from sources of colonization. By studying is- 

 land biology, museum researchers have identified some 

 general patterns of natural distribution and abundance 

 that have direct conservation implications. Working 

 in the Philippines, mammalogist Larry Heaney has stu- 

 died how extinction rates change over time. Extinc- 

 tion rates are apparently very high soon after islands 

 become isolated and subsequently decrease to minor or 

 insignificant levels. Thus, fragmentation of forests 

 through cutting should produce rapid extinctions of 

 many species, after which the communities will stabil- 

 ize. 



Small islands have long been known to support 

 impoverished faunas, but scientists have generally re- 

 garded the species comprising them as being random 

 samples of a given biota. In 1985, I noted that the spe- 

 cies found on small islands were also present on larger 

 islands, but other species are never present on small 

 islands. This pattern characterizes mammal and bird 

 fauna in several archipelagos. The significance of such 

 patterns of species richness and composition is clear: 23 



