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J Archaeol Method Theory (2013) 20:397419
DOI 10.1007/s10816-012-9166-z
Michael D. Cannon
Published online: 14 December 2012# Springer Science+Business Media New York 2012
Abstract Zooarchaeologists have long recognized that the number of identified specimens (NISP) is dependent on the degree to which bones are fragmented, but attempts are rarely made to control for the effects of fragmentation on NISP. This paper provides insight into those effects by presenting both a formal model of the relationship between NISP and fragmentation and experimental data on that relationship. The experimental data have practical implications regarding the effectiveness of potential measures of bone fragmentation, suggesting that specimen sizewhich can be determined easily through digital image analysisis more useful than other variables that have been or might be used as fragmentation measures.
Keywords Zooarchaeology . Taphonomy . Experimental archaeology . Digital image analysis
Introduction
The number of identified specimens (NISP) is the simplest measure of taxonomic abundance available to zooarchaeologists, and it is probably also the most commonly used. It has long been recognized, however, that NISP is far from perfect as a taxonomic abundance measure (e.g., Grayson 1984; Klein and Cruz-Uribe 1984; Marshall and Pilgram 1993). Among the problems that have been noted with NISP is that it varies not only with taxonomic abundance but also with the degree to which bones have been fragmented: breaking bones into more pieces means more pieces that can potentially be identified and, hence, potentially higher NISP values.
Even though zooarchaeologists have long acknowledged this, rarely do we attempt to control for the effects of fragmentation on NISP when using it to measure
M. D. Cannon (*)
SWCA Environmental Consultants, 257 East 200 South, Suite 200, Salt Lake City, UT 84111, USA e-mail: [email protected]
NISP, Bone Fragmentation, and the Measurement of Taxonomic Abundance
398 Cannon
taxonomic abundance. This is despite the fact that, without doing so, we cannot truly know whether variability in NISP is simply telling us about variability in fragmentation rather than about variability in taxonomic abundance. As I show in the succeeding paragraphs, potentially significant conclusions about prehistory that are based upon patterns in archaeofaunal taxonomic abundance may be confounded by differential rates of fragmentation among faunal samples. This paper takes steps towards developing methods for better dealing with this problem...