Premium
Experimental Manipulation of Population Density in Three Sympatric Rodents
Author(s) -
Joule James,
Jameson David L.
Publication year - 1972
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1934779
Subject(s) - sigmodon hispidus , sympatric speciation , biology , cotton rat , population density , population , homogeneous , body weight , zoology , ecology , demography , immunology , endocrinology , sociology , virus , physics , thermodynamics
Three abundant rodents, the cotton rat (Sigmodon hispidus), the harvest mouse (Reithrodontomys fulvescens), and the rice rat (Oryzomys palustris) are sympatric in southeast Texas. From January 1970 to May 1970, six presumably homogeneous areas, three control, were live—trapped. Mark—release—recapture and selective removal techniques were used to monitor species composition within the areas. Estimates of the number of individuals per species, body weights, and sex ratios were obtained at 2—week intervals. When cotton rats were experimentally removed, no change in the mean weights of harvest mice or rice rats were revealed by linear regression analysis. When harvest mice and rice rats were removed, cotton rat females exhibited a significant increase in mean weight. A significant change in sex ratio of cotton rats, from a greater proportion of males to a greater proportion of females, was recorded in the areas where harvest mice and rice rats were removed. Although the number of captures per species declined, comparisons of the different experimental manipulations could be made throughout the study.