Community reestablishment and poor body conditions of small mammal assemblages in subtropical afforested ecosystems

Abstract

Afforestation is one of the high-efficiency practices for the restoration of degraded forest ecosystems and has been increasingly used worldwide. It is crucial to determine the restoration status of wildlife in afforested forests to effectively monitor biodiversity conservation and the self-sustainability of forest ecosystems, as well as to effectively guide the implementation of afforestation projects in the future. China has the largest area of man-made forests around the world, but the effects of the restoration efforts on the faunal diversity in artificial woodlands are unclear. Here, we evaluated the effects of afforestation practices on small mammals in two types of planted forests: Japanese larch (Larix kaempferi, an introduced species) and China Armand pine (Pinus armandii, a native species) plantations, and two reference forests: young- and old-growth forests, at the community, population, and individual levels. The diversity of small mammals did not differ significantly among the four forest types and the population densities of small mammals in two plantations were between the young- and old-growth forests. Collectively, our findings indicated that small mammal assemblages had reestablished in afforested forests. Four body condition indices were measured in the Chinese white-bellied rat (Niviventer confucianus), a predominant species, and differences were found between afforested and reference forests. Chinese white-bellied rats had the lowest body masses and highest endoparasite loads in the Japanese larch planted forest, while body length or carcass mass did not differ among the four forest types. In comparison, study rats had slightly lower body masses and lower endoparasite loads in the China Armand pine planted forest than reference forests. These findings indicated that small mammals inhabiting both types of afforested forests had poor body conditions but these trends were worse in the Japanese larch planted forest, i.e., the introduced species. Given that afforestation is a widespread practice for global forest landscape restoration, we propose two suggestions to guide afforestation efforts and the subsequent management thereof: (1) native species rather than exotic species are preferable for use in afforestation projects, and (2) wildlife diversity in afforested forests should be considered when monitoring the restoration and management of degraded forest ecosystems.