Biodiv Sci ›› 2021, Vol. 29 ›› Issue (7): 980-994.DOI: 10.17520/biods.2020470

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Ecological resilience of pollination in the face of pollinator decline: Content, mechanism and perspective

Zhenghua Xie1,*(), Youqiong Wang1, Jun Cao2, Jianmin Wang3, Jiandong An4   

  1. 1 Research Institute of Insect Resources, Chinese Academy of Forestry, Kunming 650224
    2 Yunnan Key Laboratory of Plant Reproductive Adaption and Evolutionary Ecology and School of Ecology and Environmental Science, Yunnan University, Kunming 650504
    3 Yunnan Rural Science and Technology Service Centre, Kunming 650021
    4 Key Laboratory for Insect-Pollinator Biology of the Ministry of Agriculture and Rural Affairs, Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093
  • Received:2020-12-20 Accepted:2021-04-14 Online:2021-07-20 Published:2021-05-28
  • Contact: * Zhenghua Xie E-mail: cnbees@gmail.com

Abstract:

Background & Aims: Pollinators are declining worldwide and there is a global concern about how to conserve pollination services of agroforestry ecosystems. In theory, the pollination services are determined not only by the level of pollinator diversity but also by the adaptive capability of pollinator communities against disturbances. Recently, researchers have realized the importance of ecological resilience of pollination; nevertheless, the concept of ecological resilience of pollination is not clear and it is often misapplied to other ecological processes, like engineering resilience, resistance, and stability.
Objectives: This study explains the concept and content of ecological resilience of pollination and discusses the differences from other similar ecological processes. Moreover, the underlying mechanisms driving the ecological resilience of pollination are reviewed and the hypotheses explaining ecological resilience of pollination are summarized. The ecological importance of ecological resilience of pollination is addressed in terms of managing pollination functioning of agricultural ecosystems.
Progresses: Ecosystems under outer disturbances can absorb the disturbances by reorganizing the inner structures or components to let the ecosystem functioning remain unchanged or at an acceptable level. Reorganization of the pollinator communities under disturbances drives the occurrence of ecological resilience of pollination. Functional redundancy, density compensation, response diversity, interaction turnover, and cross-scale resilience are the five hypotheses explaining the ecological resilience of pollination, but they are often used imprecisely and incorrectly. We state that the five hypotheses are different but internally interlinked, explaining the ecological resilience of pollination at different spatial scales. From functional redundancy, density compensation, response diversity, interaction turnover to cross-scale resilience, the five hypotheses explain the ecological resilience of pollination ranging from small to large scales and from simple to complex ecosystems. Moreover, the hypothesis running at a relatively large spatial scale (e.g. cross-scale resilience) can be applied to explain the hypothesis at a relatively small scale (e.g. functional redundancy and density compensation). For each hypothesis, a conceptual diagram is presented to illustrate how pollinators reorganize their communities to enhance the ecological resilience of pollination. The experimental evidences to support the five hypotheses are still in shortage, particularly for interaction turnover hypothesis and the cross-scale resilience hypothesis. Nowadays, few studies have explored the pollination functioning of ecosystems by methods integrating the five hypotheses. Moreover, the relationships among the five hypotheses are not tested empirically by field study, either. Therefore, more field evidences are expected to support those hypotheses.
Perspectives: The ecological resilience of pollination is always measured using biodiversity indexes, such as species richness and Simpson diversity. Since ecological resilience of pollination is a measurement of ecosystem functioning, we suggest that its indictor need to integrate pollination functioning, such as pollen grains deposited on stigma surfaces, initial fruit sets and finial fruit sets. Future research also should examine how the disturbance intensification influences the ecological resilience of pollination and when the ecological resilience of pollination occurs. Moreover, the five hypotheses should be tested empirically and their relationships need to be explored. With the development of knowledge on ecological resilience of pollination, researchers can apply those theories to manage the agricultural ecosystems. For example, the ecological resilience of pollination can guide the researchers to determine when and how to provide the managed pollinators (e.g. honey bees) to safeguard the pollination functioning of ecosystems.

Key words: pollinator decline, pollination service, ecological resilience, engineering resilience, anthropogenic disturbance