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evolutionarily. The seaside alder ( Alnus maritlma) is such an endemic in 

 the Bay region. But many species have persisted for a very long time without 

 every becoming especially abundant. Man's mass disruption of habitats, 

 however, has radically altered the picture allowing tremendous increases in 

 the populations of species able to accommodate the changes, and driving 

 many of the remainder close to extinction. The - problem of determining 

 which species are rare is far more difficult than might be supposed. 

 First, there is in general far less interest in plants than animals 

 hence plant distributions are less well known than are most vertebrate 

 distributions. Second, records of past collections are often impossibly 

 vague, (e.g., "eastern shore," or"Somerset County," or "north of Baltimore") 

 which makes location of a plant colony virtually impossible. Third, there 

 is no available monitor of changing plant abundance. A species listed in 

 a flora (which might have been written 20 years ago or more) as abundant 

 or wide ranging might over 20 years of environmental degradation in its 

 range be completely eliminated. It was not until this past year that the 

 Smithsonian Institution pulled together a first report on endangered plants 

 of the United States. Most of the few records of endangered plants in 

 natural areas of the Bay region were taken from that source Many more 

 might be discovered it an adequate search were undertaken. 



SEASONAL CONCENTRATION OF ANIMALS 

 While endangered, rare, and uncommon species are critically important 

 and figure strongly in the selection of desirable natural areas, the 

 most striking feature of Bay wildlife is the seasonal concentration of 

 various species. There are three major groups: overwintering species, 

 seasonal breeders, and migratory stopovers. 



