The widespread transition of primary rainforest to agricultural systems, secondary forests, and tree plantations under intensive management has occurred, or is occurring, throughout the tropics. In order to guide the restoration of degraded tropical lands and achieve their long-term sustainable land use, it is imperative to better understand how deforestation, forest conversion, and land cover affect the litter conditions.
Researchers from Xishuangbanna Tropical Botanical Garden (XTBG) investigated litterfall production, standing litter and litter quality for 5 years in a tropical seasonal rainforest (TSR), tropical secondary forest (TSF), tropical anthropogenic forest (TAF), and a rubber monoculture (RM) in Xishuangbanna, SW China.
The researchers examined the differences in litterfall production, standing litter, and nutrient returns and their related nutrient use efficiency (NUE) among the four forests. They also assessed the effects of tropical forest transition on litter conditions.
They found clear differences in the community composition and vegetation characteristics among the four studied tropical forests in Xishuangbanna. The amount of litterfall, standing litter, nutrient returns, and NUE, all significantly varied with forest types, reflecting their differences in the ecophysiological responses of specific plant communities at different ages.
The annual mean litterfall was significantly higher in tropical secondary forest, followed by tropical anthropogenic forest, tropical seasonal rainforest and rubber monoculture.
Compared with the rubber monoculture and its simplified community structure, precipitation and temperature apparently had more influences on litterfall production from tropical seasonal rainforest and tropical secondary forest with their relatively species-rich communities. Similar to litter production, most of the nutrient returns occurred in the cool and dry season.
“Our results suggest that conversion of tropical primary forest to young secondary/anthropogenic forest could effectively increase litter production and nutrient returns but decrease NUE”, said Prof. LIU Wenjie, principal investigator of the study.