Data from: Megagrazer loss drives complex landscape-scale biophysical cascades

Wild animals can modulate ecosystem-climate feedbacks, e.g. through
impacts on vegetation and associated carbon dynamics. However, vegetation
cover and composition also affect land surface albedo, which is an
important component of the global energy budget. We currently know very
little about the influence of wild animals on land surface albedo and the
resulting climate forcing of these albedo changes. Leveraging a unique,
ecosystem-scale, semi-experimental approach, we study how the loss of the
world’s largest, terrestrial grazer, white rhinoceros (Ceratotherium
simum), affected the coupling between fire dynamics, woody encroachment
and surface albedo in Hluhluwe-iMfolozi Park (HiP), South Africa. Our path
analysis revealed that areas in the park where more rhinos had been
removed showed a stronger increase in burnt area and woody encroachment
compared to areas with fewer rhinos removed, which were both related to a
decrease in surface albedo. Increasing burnt area was further associated
with higher rates of woody encroachment, indirectly reinforcing the
negative effect of rhino loss on albedo. Our study demonstrates that
removing megagrazers in HiP were related to complex ecosystem-wide
cascades with measurable impacts on land cover and surface albedo and
consequences on climate forcing. This highlights the importance of
restoring functional ecosystems by reinstating trophic processes.

野生动物可调控生态系统-气候反馈过程，例如通过对植被及其相关碳动态的影响实现调控。然而，植被覆盖与组成同样会影响陆地表面反照率（land surface albedo），而后者是全球能量收支的重要组成部分。目前我们对野生动物对陆地表面反照率的影响，以及这类反照率变化所引发的气候强迫效应，尚知之甚少。本研究依托一套独特的生态系统尺度半实验方法，探究了全球最大陆生植食动物——白犀牛（Ceratotherium simum）的消失，对南非赫卢赫卢韦-因福兹公园（HiP）内火动态、木本侵占与陆地表面反照率之间耦合关系的影响。我们的路径分析（path analysis）结果显示，相较于犀牛移除量较少的区域，公园内犀牛移除量更多的区域，其火烧面积与木本侵占程度均呈现出更为显著的上升，且这两类变化均与陆地表面反照率的下降存在关联。火烧面积的进一步扩张还与更高的木本侵占速率相关，间接加剧了犀牛消失对反照率的负面影响。本研究表明，在HiP公园移除巨型植食动物，与一系列复杂的全生态系统级联效应存在关联，这些效应会对土地覆被与陆地表面反照率产生可量化的影响，并进一步影响气候强迫效应。这一研究结果凸显了通过恢复营养级过程来修复功能性生态系统的重要性。