The minimal area problem in invertebrate communities of Mediterranean rocky substrata

✍ Scribed by S. Weinberg

• Book ID: 104752156
• Publisher: Springer-Verlag
• Year: 1978
• Tongue: English
• Weight: 630 KB
• Volume: 49
• Category: Article
• ISSN: 0025-3162
• DOI: 10.1007/bf00390728

✦ Synopsis

D i f f e r e n t ways of o b t a i n i n g i n f o r m a t i o n about m i n i m a l area are studied. The classical s p e c i e s -a r e a curve lacks objectivity. Curves based on s i m i l a r i t y indices a r e objective, in so far that a critical t h r e s h o l d can be defined, w h e r e one admits that the m i n i m a l area is reached. C o m p a r i s o n is made b e t w e e n S~rensen's q u a l i t a t i v e s i m i l a r i t y index (based on presence-absence) and K u l c z y n s k i ' s q u a n t i t a t i v e similarity index (based on numbers of individuals and/or percent cover). In the shalloww a t e r rocky h a b i t a t s studied, two types of c o m m u n i t y were distinguished. The first, m i n i a t u r i z e d c o m m u n i t i e s are found in dark caves. Their m i n i m a l area is about 4,000 cm 2. The second, coarser, c o m m u n i t i e s occur on open rocks, either horizontal, sloping or vertical. Their minimal area is 20,0OO cm 2. C a l c u l a t i o n s were based mainly on O c t o c o r a l l i a ( C o e l e n t e r a t a w h i c h are assumed to be c h a r a c t e r i s t i c of the comm u n i t y as a whole.