[tlocoh-info] Using T-LoCo to look at spatial and temporal avoidance between individuals
galadrielent at yahoo.com
Wed Apr 8 22:28:43 CEST 2015
I'm working on an analysis of spider monkey space-use and social relationships. I've been using permutation tests as proposed by Whitehead et al. (2005) and Whitehead (2008) to test for preferred/avoided associations between individuals. I've done this using the SOCPROG (http://myweb.dal.ca/hwhitehe/social.htm;see citations at the end) implementation of this analysis, considering associations based on the presence of individuals in the same subgroup.
I'm also trying to come up with an equivalent analysis based on individual space-use (specifically core areas) and for this I've been using T-LoCoH. I basically came up (with a lot of help from Andy Lyons) with a random-encounter-expectation for each pair of individuals within their core areas (of course, this was only possible if the core areas/isopleth of interest intersected). This exercise is pretty rudimentary because it assumes a random-uniform distribution of individuals in space which is of course a simplification, but it was a good start. Even though I got interesting results, the resulting random expectation was several orders of magnitude smaller than the actual encounter rates for all pairs of individuals, so it wasn't very useful for distinguishing preferred/avoided associations. After recovering from the disappointment, I decided to use a dyadic-spatial-association-index (derived from the core area overlap between two individuals with respect to the sum of their core area) with a bootstrap approach to come up with confidence intervals which I'm using as limits to distinguish non-random or "outstanding" spatial associations, if you will.
I hope this gives you some ideas. I recommend taking a good look at Whitehead's work. I also recently came across the R package Digiroo2 which seems to do something similar to what I've been trying to devise, but I really haven't looked into it http://cran.r-project.org/web/packages/Digiroo2/Digiroo2.pdf
Sandra E. Smith AguilarDoctorado en Ciencias en Conservación y Aprovechamiento de Recursos NaturalesCIIDIR Unidad Oaxaca, Instituto Politécnico Nacional,
Whitehead, H., L. Bejder, and A. C. Ottensmeyer. 2005. Testing associationpatterns: issues arising and extensions. Animal Behaviour69: e1-e6.
Whitehead, H.2008. Analyzing animal societies: quantitative methods forvertebrate social analysis. University of Chicago Press, Chicago.
Whitehead, H. 2009. SOCPROG programs: analyzing animalsocial structures. Behavioral Ecology andSociobiology 63:765-778 From: Nalani Ludington <nalani.ludington at gmail.com>
To: tlocoh-info at lists.r-forge.r-project.org
Sent: Wednesday, April 8, 2015 12:44 PM
Subject: [tlocoh-info] Using T-LoCo to look at spatial and temporal avoidance between individuals
I am using T-LoCo for a study of black bear in Yosemite National Park, California. I will be examining how despotic distribution influences adult male and adult female use of areas of human development. Part of my study involves looking at males and females whose home ranges overlap in a developed area. I will look at presences and absences of each sex in the area of overlap to see if females are avoiding the shared area when a male is present. I was wondering if anyone knows if there has been any work done on a question like this using T-LoCo? The current method that I plan to use was presented in Minta 1992 (see full citation below). This method basically takes presences and absences for each animal and compares them to the expected frequency of spatially independent home range use by each animal relative to the other, and the expected frequency of temporally independent home range use by the two animals.
Minta, S.C. 1992. Test of spatial and temporal interaction among animals. Ecological Applications 2: 178-188.
Nalani LudingtonHumboldt State University Wildlife Department 1 Harpst St. Arcata, CA 95521nalani.ludington at gmail.com
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