109．Finally，for the many small mammals that supplement their insect diet withfruits or seeds an inability to span open gaps between tree crowns may beproblematic，since treesthat yield these foods can be sparse．

(特殊结构supplement…with…——以…补充)

最后，对于以水果或种子来补充其昆虫食物的许多小型哺乳动物而言，不能跨越树冠之间的无树问隙可能很成问题，因为生产这些食物的树林可能分布很稀疏。

分句1：for the many small mammals

分句2：that supplement their insect dietwith fruits or seeds an inability to span open gaps between tree crowns may beproblematic

分句3：since trees that yield these foodscan be sparse

1和2嵌套

1和3并列