TY - JOUR

T1 - Negative effects of long-term phosphorus additions on understory plants in a primary tropical forest

AU - Mao, Qinggong

AU - Chen, Hao

AU - Gurmesa, Geshere Abdisa

AU - Gundersen, Per

AU - Ellsworth, David Scott

AU - Gilliam, Frank S.

AU - Wang, Cong

AU - Zhu, Fiefei

AU - Ye, Qing

AU - Mo, Jiangming

AU - Lu, Xiankai

N1 - Funding Information: Financial support was provided by the National Natural Science Foundation of China (No. 31700422 , 41731176 , 41922056 , 31872691 ), Guangdong Basic and Applied Basic Research Foundation ( 2019A1515011642 ), and China Postdoctoral Science Foundation ( 2017M612775 ). We are grateful to Dr. Weixing Zhu and two anonymous reviewers for invaluable suggestions and comments. We appreciate Yujia Huang, Nianzhuang Liu, Lijie Deng, Juan Huang and Hui Mo for their assistance in laboratory and fieldwork. Publisher Copyright: © 2018 Elsevier B.V.

PY - 2021/12/1

Y1 - 2021/12/1

N2 - Human activities have disturbed global phosphorus (P) cycling by introducing substantial amounts of P to natural ecosystems. Although natural P gradients and fertilization studies have found that plant community traits are closely related to P availability, it remains unclear how increased P supply affects plant growth and diversity in P-deficient tropical forests. We used a decadal P-addition experiment (2007–2017) to study the effects of increased P input on plant growth and diversity in understory layer in tropical forests. We monitored the dynamics of seedling growth, survival rate, and diversity of understory plants throughout the fertilization period under control and P addition at 15 g P m−2 yr−1. To identify the drivers of responses, P concentration, photosynthesis rate and nonstructural carbon were analyzed. Results showed that long-term P addition significantly increased P concentrations both in soil pools and plant tissues. However, P addition did not increase the light-saturated photosynthesis rate or growth rate of the understory plants. Furthermore, P addition significantly decreased the survival rate of seedlings and reduced the species richness and density of understory plants. The negative effects of P addition may be attributed to an increased carbon cost due to the tissue maintenance of plants with higher P concentrations. These findings indicate that increased P supply alone is not necessary to benefit the growth of plants in ecosystems with low P availability, and P inputs can inhibit understory plants and may alter community composition. Therefore, we appeal to a need for caution when inputting P to tropical forests ecosystems.

AB - Human activities have disturbed global phosphorus (P) cycling by introducing substantial amounts of P to natural ecosystems. Although natural P gradients and fertilization studies have found that plant community traits are closely related to P availability, it remains unclear how increased P supply affects plant growth and diversity in P-deficient tropical forests. We used a decadal P-addition experiment (2007–2017) to study the effects of increased P input on plant growth and diversity in understory layer in tropical forests. We monitored the dynamics of seedling growth, survival rate, and diversity of understory plants throughout the fertilization period under control and P addition at 15 g P m−2 yr−1. To identify the drivers of responses, P concentration, photosynthesis rate and nonstructural carbon were analyzed. Results showed that long-term P addition significantly increased P concentrations both in soil pools and plant tissues. However, P addition did not increase the light-saturated photosynthesis rate or growth rate of the understory plants. Furthermore, P addition significantly decreased the survival rate of seedlings and reduced the species richness and density of understory plants. The negative effects of P addition may be attributed to an increased carbon cost due to the tissue maintenance of plants with higher P concentrations. These findings indicate that increased P supply alone is not necessary to benefit the growth of plants in ecosystems with low P availability, and P inputs can inhibit understory plants and may alter community composition. Therefore, we appeal to a need for caution when inputting P to tropical forests ecosystems.

KW - Community composition

KW - Diversity

KW - Phosphorus limitation

KW - Survival rate

KW - Tropical forests

KW - Understory plants

U2 - 10.1016/j.scitotenv.2021.149306

DO - 10.1016/j.scitotenv.2021.149306

M3 - Journal article

C2 - 34340072

AN - SCOPUS:85111614932

VL - 798

JO - Science of the Total Environment

JF - Science of the Total Environment

SN - 0048-9697

M1 - 149306

ER -