Moorhouse, T. P. et al.: Effects of forage availability on growth and maturationrates in water voles

Tom P. Moorhouse, Merryl Gelling and David W. Macdonald: Effects of forage availability on growth and maturationrates in water voles.
In: Journal of Animal Ecology 2008,77 , 1288–1295.

Link: http://www.academia.edu/169019/Effects_of_forage_availability_on_growth_and_maturation_rates_in_water_voles

Zitat :

Summary

1. In populations of small mammals, food supplementation typically results in higher populationdensities, body weights, growth rates and reproductive rates. However, few studies have demon-strated a relationship between forage levels and demographic rates in wild populations in theabsence of supplementation.
2. We examined the association of levels of available forage with individual growth rates and timeto 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 andindividual 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 formales and did not vary between study sites. Differences in growth rates therefore translated into dif-ferences in the time taken to reach maturity between sites.
5. In the re-introduced populations, mean days to maturity varied inversely with mean rangelength. Females took 7 days (18%, range 40–47 days) longer and males 5 days (13%, range 40–45days) 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 densitiesmay reduce maturation rates in water voles through a reduction in mean range size, thereby limitingthe availability of forage to each individual.