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A N e w Y o r k C a s e S t u d y : The Decline of an Endangered Species By Timothy L. McCabe Senior Scientist and Curator of Entomology New York State Museum The Karner blue butterfly serves as an indicator of the environmental health of the Albany pine barrens. The Karner blue larvae are dependent on a single host plant—the blue lupine. Lupine requires a complex mix of fire, low graze pressure from herbivores, and disturbance. The butterflies have equally complex needs for winter snow cover, nectar sources, ant symbionts and traffic-free areas. In preserves, deer and rabbit populations are protected from exploitation, enabling them to build large populations. The resulting increased browsing puts unnatural pressure on selected plants, particularly the lupine, thus reducing host availability. The Karner blue butterflies disperse across the landscape, taking advantage of unexploited habitat. They may stay in an area for 20 years, then disappear as the area becomes more overgrown and shaded. Managing the habitat is important for the future of this species. Currently, unused suitable habitat necessary for establishing new populations is being destroyed. The delicate balance between the butterfly and habitat has been exemplified by its extirpation from four states. The Karner blue is found in Albany, Schenectady and Warren counties. Originally, the Albany pine barrens comprised 25,000 acres. Now there are less than 2,800 acres of undeveloped land. Loss of pine barrens habitat through development has resulted in a corresponding decline in butterfly abundance. Figure 1 is an example of a site that has experienced a severe decline with the population apparently being extirpated. However, at most other sites in the Albany pine barrens, the decline has not been as severe as in this example. This decline became well known in the late 1970s and early ’80s through a city-sponsored Environmental Impact Statement. B i o l o g i c a l 10 D i v e r s i t y
12 10 Number of Butterflies Observed 8 6 4 2 0 1991 1992 1993 1994 1995 1996 1997 1998 Survey Year F i g u r e 1 . Data were collected by observing and counting adult butterflies at one site in the Albany pine barrens. This visual survey method gives researchers a relative population index number, which, although it is not the actual population size, is very useful for monitoring some organisms such as butterflies. Each bar on the graph represents the total number of butterflies counted on different days. There were no butterflies observed on surveys in 1997 and 1998. (Data courtesy of the Albany Pine Bush Preserve Commission.) B i o l o g i c a l 11 D i v e r s i t y
Page 1: Biological Diversity: T H E O L D E
Page 4 and 5: THE UNIVERSITY OF THE STATE OF NEW
Page 6 and 7: Copyright © 1999 by The New York S
Page 9 and 10: Preface This book is based on a man
Page 11 and 12: Additional information on the activ
Page 13 and 14: Biological Diversity: T H E O L D E
Page 15 and 16: some degree of potency. A much high
Page 17 and 18: Some groups of organisms, such as f
Page 19 and 20: to their environment and to one ano
Page 21: N EW YORK’S BIODIVERSITY IS THREA
Page 25 and 26: It is possible that the next hundre
Page 27 and 28: environment. For almost 3 billion y
Page 29 and 30: W ITH ITS WISPINESS AND LIGHT-AND-D
Page 31 and 32: sophisticated microscopic and bioch
Page 33 and 34: The tropical zones generally have a
Page 35 and 36: average as well as greater ecologic
Page 37 and 38: early extinction within the next 30
Page 39 and 40: perished. As the paleontologist Dav
Page 41 and 42: collected in the stream in 1936 and
Page 43 and 44: Systematics, or taxonomy, is at the
Page 45 and 46: Community ecology addresses the man
Page 47 and 48: Biological field stations from four
Page 49 and 50: Biogeography 1 The scientific study
Page 51 and 52: Dispersal In biology, the way a spe
Page 53 and 54: Global warming An increase in the c
Page 55 and 56: Ozone A form of oxygen (O 3 ) that
Page 57 and 58: Termites A group of insects that is
Page 59 and 60: Grifo, Francesca, and J. Rosenthal
Page 61 and 62: diverse and why the threat to that
Page 63 and 64: Mitchell, Richard S., L. Danaher, a
Page 65 and 66: 9. Is an ecologist the same as a ta
Page 67 and 68: 31. Do you know of a biological res
Page 69 and 70: B i o l o g i c a l 57 D i v e r s
Page 72:
THE NEW YORK STATE MUSEUM IS A PROG
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