Hurley Mark A, Hebblewhite Mark, Gaillard Jean-Michel, Dray Stéphane, Taylor Kyle A, Smith W K, Zager Pete, Bonenfant Christophe
Idaho Department of Fish and Game, , Salmon, ID, USA.
Philos Trans R Soc Lond B Biol Sci. 2014 Apr 14;369(1643):20130196. doi: 10.1098/rstb.2013.0196. Print 2014.
Large herbivore populations respond strongly to remotely sensed measures of primary productivity. Whereas most studies in seasonal environments have focused on the effects of spring plant phenology on juvenile survival, recent studies demonstrated that autumn nutrition also plays a crucial role. We tested for both direct and indirect (through body mass) effects of spring and autumn phenology on winter survival of 2315 mule deer fawns across a wide range of environmental conditions in Idaho, USA. We first performed a functional analysis that identified spring and autumn as the key periods for structuring the among-population and among-year variation of primary production (approximated from 1 km Advanced Very High Resolution Radiometer Normalized Difference Vegetation Index (NDVI)) along the growing season. A path analysis showed that early winter precipitation and direct and indirect effects of spring and autumn NDVI functional components accounted for 45% of observed variation in overwinter survival. The effect size of autumn phenology on body mass was about twice that of spring phenology, while direct effects of phenology on survival were similar between spring and autumn. We demonstrate that the effects of plant phenology vary across ecosystems, and that in semi-arid systems, autumn may be more important than spring for overwinter survival.
大型食草动物种群对遥感测量的初级生产力反应强烈。虽然大多数在季节性环境中的研究都集中在春季植物物候对幼崽存活的影响上，但最近的研究表明秋季营养也起着关键作用。我们在美国爱达荷州广泛的环境条件下，测试了春季和秋季物候对2315只骡鹿幼崽冬季存活的直接和间接（通过体重）影响。我们首先进行了功能分析，确定春季和秋季是构建生长季节初级生产（根据1千米高级甚高分辨率辐射计归一化植被指数（NDVI）估算）种群间和年间变化的关键时期。路径分析表明，初冬降水以及春季和秋季NDVI功能成分的直接和间接影响占观察到的越冬存活变化的45%。秋季物候对体重的影响大小约为春季物候的两倍，而物候对存活的直接影响在春季和秋季相似。我们证明植物物候的影响在不同生态系统中有所不同，并且在半干旱系统中，秋季对于越冬存活可能比春季更重要。
