DOI: 10.5061/dryad.c3tc6
title: Data from: Empirical tests of harvest-induced body-size evolution along a geographic gradient in Australian macropods

description: 1. Life-history theory predicts the progressive dwarfing of animal
 populations that are subjected to chronic mortality stress but the
 evolutionary impact of harvesting terrestrial herbivores has seldom been
 tested. In Australia, marsupials of the genus Macropus (kangaroos and
 wallabies) are subjected to size-selective commercial harvesting.
 Mathematical modelling suggests that harvest quotas (ca. 10–20 % of
 population estimates annually) could be driving body-size evolution in
 these species. 2. We tested this hypothesis for three harvested macropod
 species with continental-scale distributions. To do so, we measured more
 than 2 000 macropod skulls sourced from wildlife collections spanning the
 last 130 years. We analysed these data using spatial Bayesian models that
 controlled for the age and sex of specimens as well as environmental
 drivers and island effects. 3. We found no evidence for the hypothesized
 decline in body size for any species; rather, models that fit trend terms
 supported minor body size increases over time. This apparently
 counterintuitive result is consistent with reduced mortality due to a
 depauperate predator guild and increased primary productivity of grassland
 vegetation following European settlement in Australia. 4. Spatial patterns
 in macropod body size supported the heat dissipation limit and
 productivity hypotheses proposed to explain geographic body-size variation
 (i.e., skull size increased with decreasing summer maximum temperature and
 increasing rainfall, respectively). 5. There is no empirical evidence that
 size-selective harvesting has driven the evolution of smaller body size in
 Australian macropods. Bayesian models are appropriate for investigating
 the long-term impact of human harvesting because they can impute missing
 data, fit non-linear growth models and account for non-random spatial
 sampling inherent in wildlife collections.
description: Macropod specimen
 details and extracted spatial covariate valuesThis file provides the
 following information for macropod skulls of three Macropus species
 sourced from nine wildlife collections: Species, Longitude (as recorded on
 the specimen tag), Latitude (as recorded on the specimen tag),
 gridLongitude (the central longitude of the grid cell from which
 covariates were extracted for the specimen), gridLatitude (the central
 latitude of the grid cell from which covariates were extracted for the
 specimen), Sex, Island, Year (the year of collection as recorded on the
 specimen tag), MI (molar index), CL (condylobasal length), WinterMinTemp
 (mean minimum temperature over the winter months), SummerMaxTemp (mean
 maximum temperature over the summer months), SummerWetBulbTemp (mean wet
 bulb temperature over the summer months), AnnualRain (mean annual
 rainfall), AnnualNDVI (mean annual Normalised Difference Vegetation
 Index), GrowSeasRain (mean rainfall during the growing season),
 GrowSeasNDVI (mean Normalised Difference Vegetation Index during the
 growing season), MinSeasRain (mean rainfall of the driest season),
 MinSeasNDVI (mean Normalised Difference Vegetation Index for the season
 with the lowest mean NDVI).ProwseEtAl_MacropodData.csv