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Effects of forage availability on growth and maturation rates in water voles
Author(s) -
Moorhouse Tom P.,
Gelling Merryl,
Macdonald David W.
Publication year - 2008
Publication title -
journal of animal ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.134
H-Index - 157
eISSN - 1365-2656
pISSN - 0021-8790
DOI - 10.1111/j.1365-2656.2008.01431.x
Subject(s) - forage , biology , zoology , sexual maturity , range (aeronautics) , bovidae , population , ecology , growth rate , demography , materials science , geometry , mathematics , sociology , composite material
Summary1 In populations of small mammals, food supplementation typically results in higher population densities, body weights, growth rates and reproductive rates. However, few studies have demonstrated a relationship between forage levels and demographic rates in wild populations in the absence of supplementation. 2 We examined the association of levels of available forage with individual growth rates and time to sexual maturity in eight re‐introduced and three naturally occurring populations of water voles ( Arvicola terrestris ). 3 Range sizes were smaller at sites with higher population densities. Mean forage availability and individual growth rates covaried with range size at each site. 4 The weight at which water voles became sexually mature was 112 g for females and 115 g for males and did not vary between study sites. Differences in growth rates therefore translated into differences in the time taken to reach maturity between sites. 5 In the re‐introduced populations, mean days to maturity varied inversely with mean range length. Females took 7 days (18%, range 40–47 days) longer and males 5 days (13%, range 40–45 days) longer to reach breeding condition at the sites with the shortest mean range lengths. 6 Evidence from this study suggests a possible mechanism by which increased population densities may reduce maturation rates in water voles through a reduction in mean range size, thereby limiting the availability of forage to each individual.