Geomorphology and Ecosystems

INTRODUCTION sys t em and on a v a r i e t y of t ime s c a l e s . Hack and G o o d l e t t (1960) a r g u e t h a t t h e l a n d s c a p e and v e g e t a t i o n development models N a t u r a l ecosys tems deve lop th rough the i n t e r p l a y of p h y s i c a l and b i o l o g i c a l f ac c f Davis and Clements are i n c o r r e c t i n t o r s . B i o l o g i c a l f a c t o r s have t r a d i t i o n a l l y t h e i r a p p l i c a t i o n t o t h e Appalachian Mounbeen emphasized because most e c o l o g i s t s have t a i n s where t hey were i n i t i a l l y developed. l i f e s c i e n c e backgrounds. The purpose of t h i s pape r i s t o e x p l o r e t h e s i g n i f i c a n c e of e a r t h s c i e n c e p e r s p e c t i v e s i n unders t a n d i n g ecosys tems. P a r t i c u l a r l y i n mount a i n l a n d s c a p e s and a long streams and r i v e r s , geomorphic p r o c e s s e s and landforms have i m p o r t a n t r o l e s i n t h e development and geographic d i s t r i b u t i o n of p l a n t and animal communit ies. Geomorphologists and ecolog i s t s working i n t h e s e dynamic l andscapes have l o n g r e l i e d on i n s i g h t s from each o t h e r ' s d i s c i p l i n e t o i n t e r p r e t causes and p a t t e r n s of e c o l o g i c and geomorphic change. The f u l l r i c h n e s s of geomorphicbiologic i n t e r a c t i o n s r e a l l y emerges from programs of ecosys tem a n a l y s i s where e a r t h and l i f e s c i e n t i s t s work c l o s e l y t o g e t h e r on comm o n t o p i c s , s i t e s , and time f rames . I n t h e p r et w e n t i e t h c e n t u r y era of n a t u r a l i s t s , t h e mixing of e a r t h and l i f e s c i e n c e p e r s p e c t i v e s w a s common. I n t h i s c e n t u r y , t h e r e h a s been p a r a l l e l i s m and i n t e r c h a n g e i n t h e e v o l u t i o n of g e n e r a l models i n geomorphology, p l a n t ecology, and animal ecology (Drury and N i s b e t , 1 9 7 1 ) . W i l l i a m Mor r i s Davis' c y c l i c a l model of long-term (107-108 y e a r s ) landform development se t t h e s t a g e f o r t h e views of veget a t i o n development p u t f o r t h by Clements (1936) and Braun (1950). The i n t e r p r e t e d vegetation and 1 andforms as p r o g r e s s i n g tog e t h e r toward a common end po in t t he penep l a i n w i t h deep mature s o i l s and "climax" v e g e t a t i o n on a n e a r l y l e v e l l andscape .