A Migratory Northern Ungulate in the Pursuit of Spring: Jumping or Surfing the Green Wave?
A Migratory Northern Ungulate in the Pursuit of Spring: Jumping or Surfing the Green Wave?
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DOI：
10.1086/667590
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发表时间：
2012-10-01
影响因子：
2.9
通讯作者：
Mysterud, Atle
中科院分区：
文献类型：
--
作者：
Bischof, Richard;Loe, Leif Egil;Mysterud, Atle
牧草成熟假说（FMH）指出，草食动物迁移沿着植物发育的物候梯度，以最大限度地提高能量摄入。尽管强烈支持FMH，植物物候和有蹄类动物运动之间的实际关系仍然是谜。我们链接植物物候（MODIS标准化差异植被指数[NDVI]数据）和空间使用的167个迁移和78个居民红鹿（马鹿），使用空间-时间-时间矩阵的“春天”，定义为瞬时速率的绿色。与FMH一致，移民比居民更容易获得早期植物物候学。鹿也更有可能迁徙到那些迁徙导致春季收获更大的地区。在迁徙过程中，迁徙的红鹿不是“在绿色浪潮中冲浪”，而是从冬季迅速移动到夏季，从而“跳过绿色浪潮”。“然而，移民和居民（在较小程度上）确实通过对栖息地使用进行较小规模的调整，在生长季节的部分时间里跟踪了物候学上的绿色。尽管它们的生活史有明显的差异，但在这项研究中，我们发现雄性和雌性红鹿之间只有微小的差异。我们确实发现的这些差异指向了女性空间使用策略的额外限制，例如产犊和照顾依赖后代所造成的限制。我们的结论是，而在某些系统的迁移本身是一种方式冲浪的绿色波，在其他人可能只是一种手段，以重新连接在夏季范围的物候春天。鉴于普遍存在的人为环境变化，了解绿色浪潮和有蹄类动物空间利用之间的关系，对管理和保护迁徙有蹄类动物和迁徙现象本身具有重要意义。
The forage-maturation hypothesis (FMH) states that herbivores migrate along a phenological gradient of plant development in order to maximize energy intake. Despite strong support for the FMH, the actual relationship between plant phenology and ungulate movement has remained enigmatic. We linked plant phenology (MODIS-normalized difference vegetation index [NDVI] data) and space use of 167 migratory and 78 resident red deer (Cervus elaphus), using a space-time-time matrix of "springness," defined as the instantaneous rate of green-up. Consistent with the FMH, migrants experienced substantially greater access to early plant phenology than did residents. Deer were also more likely to migrate in areas where migration led to greater gains in springness. Rather than " surfing the green wave" during migration, migratory red deer moved rapidly from the winter to the summer range, thereby " jumping the green wave." However, migrants and, to a lesser degree, residents did track phenological green-up through parts of the growing season by making smaller-scale adjustments in habitat use. Despite pronounced differences in their life histories, we found only marginal differences between male and female red deer in this study. Those differences that we did detect pointed toward additional constraints on female space-use tactics, such as those posed by calving and caring for dependent offspring. We conclude that whereas in some systems migration itself is a way to surf the green wave, in others it may simply be a means to reconnect with phenological spring at the summer range. In the light of ubiquitous anthropogenic environmental change, understanding the relationship between the green wave and ungulate space use has important consequences for the management and conservation of migratory ungulates and the phenomenon of migration itself.