Phenological changes offset the warming effects on biomass production in an alpine meadow on the Qinghai–Tibetan Plateau

Abstract

Phenology is an important indicator of plant responses to environmental changes and is closely correlated with biomass production. However, how changes in phenological events affect plant biomass production when exposed to changing temperature and precipitation remain unclear. We conducted a 4‐year manipulative experiment of warming and precipitation addition to explore phenology–biomass interactions under climate change in a dry alpine meadow on the central Qinghai–Tibetan Plateau from 2015 to 2018. In dry and warm years, warming delayed phenology and precipitation addition advanced them. Warming decreased the biomass of Kobresia pygmaea in 2018 and the biomass of Poa pratensis in 2015, 2017 and 2018. However, precipitation addition significantly increased the biomass of Poa pratensis and Potentilla multifida in most of the experimental years. Phenological changes regulated the responses of biomass to treatments. Specifically, delay of green up of P. pratensis and delay of withering of K. pygmaea induced by warming can increase biomass production, but it can be offset by the direct negative effects of warming on biomass. Synthesis. Here we show how warming‐induced drought tend to decrease the biomass production of graminoids and the negative effects of warming on the biomass of P. pratensis and K. pygmaea were partially offset by green up postponement and withering postponement respectively. Our results highlights phenology is a crucial regulator for biomass production under climate change. Hence, both direct and indirect effects of warming and precipitation addition on phenology and biomass cannot be ignored when predicting biomass responses to climate change.

A Mechanistic Framework for Understanding the Effects of Climate Change on the Link Between Flowering and Fruiting Phenology

“…Finally, environmental controls could interact with other factors influencing a species' phenology and our other proposed mechanisms. For example, higher temperatures due to climate change could interact with biogeography (e.g., Loarie et al, 2009;Butt et al, 2015;Ge et al, 2015, reviewed in Du et al, 2020, phylogeny (Davis et al, 2010), and life form (Du et al, 2020;Ganjurjav et al, 2021) to produce patterns in the FTFI across many species.…”

Precipitation regulates the livestock dung seed bank through above ground vegetation productivity in the Qaidam basin

“…This phenomenon has also been verified in other arid regions (Gherardi & Sala, 2018; Huxman et al, 2004; Lehouerou et al, 1988). The reason may be that an increase in precipitation leads to the advancement of the greening period of plants and the postponement of the withering period (Ganjurjav et al, 2020); that is, precipitation can prolong the plant growth period and ultimately increases the aboveground biomass. In addition, moisture is a prerequisite for seed germination (Wang et al, 2020).…”

Climate warming interacts with other global change drivers to influence plant phenology: A meta‐analysis of experimental studies

“…in a temperate‐boreal forest ecotone but not when it was accompanied by decreased precipitation (Rice et al, 2021). However, positive effects of warming on plant phenology may be intensified by increased precipitation, as this could counteract the desiccating effects of warming (Ganjurjav et al, 2021). Greater positive impacts on leaf colouring have also been found under simultaneous warming and elevated CO 2 (Reyes‐Fox et al, 2014), perhaps because elevated CO 2 is associated with reduced stomatal conductance (Hetherington & Woodward, 2003), reducing water losses and enabling an extension of plant growing season under climate warming.…”