Analysis of spatial association between two species based on the interspecies mean crowding

Abstract

Summary and ConclusionThe measurement of spatial association between two species is considered on the basis of interspecies mean crowding. Two indices of overlapping, γ and Cp, are derived as geometric and weighted arithmetic means of the same component ratios related to inter‐and intraspecies mean crowdings. Both indices behave in a similar way, ranging from 1 when the distributions of two species are completely overlapped to 0 when they are completely exclusive with each other. The former is essentially identical with indices proposed byKuno (1968) andPianka (1973), and the latter is a modified form ofMorisita's (1959)Cσ index. Indices to measure the degree of spatial correlation between species, Ω and Rμ, are then derived for both kinds of overlapping indices, which vary from 1 in complete overlapping, through 0 in independent occurrence, to −1 in complete exclusion.Various kinds of interspecies association are analyzed using these indices and an extended form of the regression graph which provides a convenient way of indicating the spatial interrelation between two species as well as distribution patterns of respective species.The method presented in this paper may also be applicable to compare temporal distribution patterns between species, similarity between communities, etc. For such a wider application which includes continuous as well as discrete distributions, the interpretation of intra‐and interspecies mean crowdings is not necessarily appropriate, and hence the concept of mean concentration with the symbols and for intraspecies relation and and for interspecies relation is suggested.

Spatial Distributions of Wind-dispersed Fruits and Trees of Swintonia schwenkii (Anacardiaceae) in a Tropical Forest of West Sumatra.

“…In Padang city the annual precipitation is about 4764 mm/yr and annual mean temperature is 27.0 "C (Hotta ed., 1984 (Iwao, 1977), of which results are given in Table 2. 100' 30'E). one of 55 m in height whose crown is drawn with broken line in Fig.…”

“…The distributional pattems of fallen fruits and trees seemed to have no clear relationships with the topography. (Iwao, 1977) The relations between the distributions of fruits and of trees of different layers were analyzed using the ol index of Iwao (1977). C) = 1 when the distributions of two species are completely the same, o = 0 when they are independent and o = -1 when they are completely exclusive.…”

T-pattern analysis for the study of temporal structure of animal and human behavior: A comprehensive review

“…and may thus be subjected to the same kinds of analyses and modeling of their distributions in time and space, for example, Markov Chain analysis (Grinstead and Snell, 2012), Iwao's omega (Iwao, 1977), and numerous other kinds of analyses. While Markov Chain models traditionally involve a minimum of contextual memory, T-pattern analysis is concerned with contextual effects in terms of multiordinal or complex-conditional probabilities between simple behaviors and patterns of these and is thus potentially useful in various molar approaches such as, for example, advocated by Rachlin (1986) and decision making processes as discussed by Rachlin and Siegel (1994), Kudadjie-Gyamfi and Rachlin (1996) among others.…”

Litterfall of a subtropical evergreen broad-leaved forest in Okinawa island, Japan

“…To measure overlap, the following indexes: and (Iwao, 1977) were used. for for where m X is the mean of item X.…”