East Lake （Credit: IHB)

Clarifying the maintenance mechanism of biodiversity on ecosystem stability is crucial for achieving ecosystem functions and services. Previous research that addressing the diversity-asynchrony-stability relationships has mainly focused on a single trophic level, especially the effects of population asynchrony, leaving the dynamics of these relationships across multiple trophic levels poorly understood.

Community stability may also be affected by trophic community asynchrony, which may cause a mismatch between consumer demand and resource availability, consequently, decreasing trophic interactions. Given that current climate change fundamentally alters seasonality and may erode key seasonally stabilising structures in nature, elucidating the mechanisms by which population asynchrony within and between trophic levels affects seasonal community stability is crucial.

A researchgroup led by Prof. XIE Ping from the Institute of Hydrobiology (IHB) of the Chinese Academy of Sciences revealed that population asynchrony within and between trophic levels have contrasting effects on consumer community stability in the lake ecosystem. This study was published in Journal of Animal Ecology.

In this study, researchers developed the concept of “trophic community asynchrony”, which is quantified as community asynchrony between resources and consumers over time, similar to the calculation method for population asynchrony among species, rather than based on phenological mismatch.

Based on monthly monitoring data from the Donghu Experimental Station of the Chinese Ecosystem Research Network (CERN) from 2003 to 2020, the researchers assessed how population asynchrony within and between trophic levels (i.e. zooplankton and phytoplankton) affects seasonal ecosystem stability under the increasing pressures of climate warming, fish consumption and nutrient enrichment.

The linear mixed-effects models (LMMs) and structural equation models (SEMs) results showed that species diversity promoted community stability mainly by increasing population asynchrony both for phytoplankton and zooplankton. Trophic community asynchrony had a significant negative effect on zooplankton community stability rather than that of phytoplankton, which supports the match-mismatch hypothesis that trophic mismatch has negative effects on consumers.

Furthermore, the results of SEMs showed that warming and top-down effects may simultaneously alter community stability through population dynamics processes within and between trophic levels, whereas nutrients act on community stability mainly through the processes within trophic levels. Moreover, the researchers found that rising water temperature decreased trophic community asynchrony, which may challenge the prevailing idea that climate warming increases the trophic mismatch between primary producers and consumers.

This study provides the first evidence that population and trophic community asynchrony have contrasting effects on consumer community stability, which offers a valuable insight for addressing global environmental change. 

(Editor: MA Yun)