{"title":"Interactive effects of management and temperature anomalies on CO2 fluxes recorded over 18 years in a temperate upland grassland system","authors":"Bruna Winck, Katja Klumpp, Juliette M.G. Bloor","doi":"10.1016/j.agrformet.2024.110343","DOIUrl":null,"url":null,"abstract":"<div><div>Temperature anomalies such as heat waves and cold spells are increasingly common, posing threats to ecosystem functioning and delivered services. Although temperature anomalies have been shown to limit broad-scale patterns of carbon sequestration, fine-scale studies on CO<sub>2</sub> fluxes and temperature anomalies are limited and interactions between temperature anomalies and agricultural management remain poorly understood. Using long-term data on grassland CO<sub>2</sub> fluxes and air temperature (2003-2021), we investigated the effects of temperature anomalies (cold, warm, extreme cold, extreme warm) on gross primary productivity and ecosystem respiration in adjacent upland mesic grasslands subjected to either extensive or intensive cattle grazing management treatments. Both warm and cold temperature anomalies occurred throughout the study period, with 40 days per year on average classed as colder or warmer compared to normal. Irrespective of management treatment and flux type, we found that temperature anomalies had a significant effect on the magnitude of CO<sub>2</sub> fluxes, the relationship between air temperature and CO<sub>2</sub> fluxes, and the occurrence of anomalous flux events. The magnitude of CO<sub>2</sub> fluxes was most affected by temperature anomalies at the start of the growing season, and fluxes were generally more sensitive to warm rather than cold temperature anomalies. However, cold temperature anomalies promoted asynchrony between C uptake and loss. Temperature-CO<sub>2</sub> flux relationships were upregulated by warm temperature anomalies in spring but down-regulated in summer and autumn, with greater reductions in flux process rates in the intensive management treatment. Nevertheless, temperature anomalies were not found to be a strong driver of flux anomalies in this study system. Collectively, our results show that grassland management interacts with the timing and nature of temperature anomalies on CO<sub>2</sub> fluxes and suggest that low grassland management intensity may buffer CO<sub>2</sub> fluxes against warm air temperature anomalies in cool temperate systems, with implications for adaptation strategies for grasslands under climate change.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"362 ","pages":"Article 110343"},"PeriodicalIF":5.6000,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Agricultural and Forest Meteorology","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0168192324004568","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"AGRONOMY","Score":null,"Total":0}
引用次数: 0
Abstract
Temperature anomalies such as heat waves and cold spells are increasingly common, posing threats to ecosystem functioning and delivered services. Although temperature anomalies have been shown to limit broad-scale patterns of carbon sequestration, fine-scale studies on CO2 fluxes and temperature anomalies are limited and interactions between temperature anomalies and agricultural management remain poorly understood. Using long-term data on grassland CO2 fluxes and air temperature (2003-2021), we investigated the effects of temperature anomalies (cold, warm, extreme cold, extreme warm) on gross primary productivity and ecosystem respiration in adjacent upland mesic grasslands subjected to either extensive or intensive cattle grazing management treatments. Both warm and cold temperature anomalies occurred throughout the study period, with 40 days per year on average classed as colder or warmer compared to normal. Irrespective of management treatment and flux type, we found that temperature anomalies had a significant effect on the magnitude of CO2 fluxes, the relationship between air temperature and CO2 fluxes, and the occurrence of anomalous flux events. The magnitude of CO2 fluxes was most affected by temperature anomalies at the start of the growing season, and fluxes were generally more sensitive to warm rather than cold temperature anomalies. However, cold temperature anomalies promoted asynchrony between C uptake and loss. Temperature-CO2 flux relationships were upregulated by warm temperature anomalies in spring but down-regulated in summer and autumn, with greater reductions in flux process rates in the intensive management treatment. Nevertheless, temperature anomalies were not found to be a strong driver of flux anomalies in this study system. Collectively, our results show that grassland management interacts with the timing and nature of temperature anomalies on CO2 fluxes and suggest that low grassland management intensity may buffer CO2 fluxes against warm air temperature anomalies in cool temperate systems, with implications for adaptation strategies for grasslands under climate change.
期刊介绍:
Agricultural and Forest Meteorology is an international journal for the publication of original articles and reviews on the inter-relationship between meteorology, agriculture, forestry, and natural ecosystems. Emphasis is on basic and applied scientific research relevant to practical problems in the field of plant and soil sciences, ecology and biogeochemistry as affected by weather as well as climate variability and change. Theoretical models should be tested against experimental data. Articles must appeal to an international audience. Special issues devoted to single topics are also published.
Typical topics include canopy micrometeorology (e.g. canopy radiation transfer, turbulence near the ground, evapotranspiration, energy balance, fluxes of trace gases), micrometeorological instrumentation (e.g., sensors for trace gases, flux measurement instruments, radiation measurement techniques), aerobiology (e.g. the dispersion of pollen, spores, insects and pesticides), biometeorology (e.g. the effect of weather and climate on plant distribution, crop yield, water-use efficiency, and plant phenology), forest-fire/weather interactions, and feedbacks from vegetation to weather and the climate system.