Consequences of More Extreme Precipitation Regimes for Terrestrial Ecosystems

Knapp, Alan K.; Beier, Claus; Briske, David D.; Classen, Aimée T.; Luo, Yiqi; Reichstein, Markus; Smith, Melinda D.; Smith, Stanley D.; Bell, Jesse E.; Fay, Philip A.; Heisler, Jana L.; Leavitt, Steven W.; Sherry, Rebecca A.; Smith, Benjamin; Weng, Ensheng

doi:10.1641/b580908

Cited by 1,005 publications

(904 citation statements)

References 65 publications

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“…Soil microbes may be activated by small rainfall events at lower threshold compared with plants 30,32 . As microbial mineralization of soil organic matter is typically the main source of soil inorganic N 33 , if soil microbes are activated by rainfall, there may be a pulse of high N availability to plants 4 . But if there is an asynchrony in N-cycling via water limitation on plant N uptake, the mineralized N is subject to nitrification and denitrification losses.…”

Section: Discussionmentioning

confidence: 99%

“…As a consequence of global warming and associated climate change, the total area of drylands is predicted to increase globally 2 ; more extreme climatic regimes will make arid and semi-arid ecosystems more vulnerable to increased risk of drought as well as increased probability of intense rain [3][4][5] . Assessing this vulnerability is a major challenge for ecologists and land managers in developing effective adaptation strategies.…”

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confidence: 99%

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Aridity threshold in controlling ecosystem nitrogen cycling in arid and semi-arid grasslands

et al. 2014

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Higher aridity and more extreme rainfall events in drylands are predicted due to climate change. Yet, it is unclear how changing precipitation regimes may affect nitrogen (N) cycling, especially in areas with extremely high aridity. Here we investigate soil N isotopic values (d 15 N) along a 3,200 km aridity gradient and reveal a hump-shaped relationship between soil d 15 N and aridity index (AI) with a threshold at AI ¼ 0.32. Variations of foliar d 15 N, the abundance of nitrification and denitrification genes, and metabolic quotient along the gradient provide further evidence for the existence of this threshold. Data support the hypothesis that the increase of gaseous N loss is higher than the increase of net plant N accumulation with increasing AI below AI ¼ 0.32, while the opposite is favoured above this threshold. Our results highlight the importance of N-cycling microbes in extremely dry areas and suggest different controlling factors of N-cycling on either side of the threshold.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Aridity threshold in controlling ecosystem nitrogen cycling in arid and semi-arid grasslands

et al. 2014

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“…Theoretical models that are supported by recent empirical data predict that precipitation events will become more intense, less frequent, and generally less predictable with current climate warming trends (Knapp et al 2008). Though numerous studies have examined the effects of water stress on plant-herbivore interactions, there still is no general predictive framework on the outcome of these interactions and their impact on the third trophic level (Alberti et al 2007, Joern & Mole 2005, Wirth & Leal 2001.…”

Section: Discussionmentioning

confidence: 99%

Caterpillar abundance and parasitism in a seasonally dry versus wet tropical forest of Panama

et al. 2010

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Abstract:Rainfall seasonality can strongly influence biotic interactions by affecting host plant quality, and thus potentially regulating herbivore exposure to natural enemies. Plant defences are predicted to increase from dry to wet forests, rendering wet-forest caterpillars more vulnerable to parasitoids due to the slow-growth-high-mortality hypothesis. We collected and reared caterpillars from the understorey and trail edges of a wet forest and a seasonally dry forest to determine whether wet-forest caterpillars suffered a higher prevalence of parasitism and were less abundant than dry-forest caterpillars. In the two forests, caterpillar abundances (on average 8 h −1 ) and prevalence of parasitism (18%) were very similar regardless of feeding niche for both parasitism (27% versus 29% in shelter builders, and 16% versus 11% in external feeders) and caterpillar abundances (shelter builders: 1.42 versus 2.39, and external feeders: 8.27 versus 5.49 caterpillars h −1 ) in the dry and wet forests, respectively. A similar comparative analysis conducted in the canopy and understorey of the dry forest revealed a higher prevalence of parasitism in the canopy (43%) despite caterpillar densities similar to those in the understorey. Overall, shelter builders suffered higher parasitism than external feeders (32% versus 14.9%), and were attacked primarily by flies, whereas external feeders were more vulnerable to attack by parasitoid wasps.

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“…As a result of increased temperatures, a concomitant increase in the frequency and duration of drought events in mesic ecosystems is anticipated (Knapp et al, 2008). The expected exposure to water stress is likely to affect both microbial and plant communities by interrupting key nutrient cycles and plant-microbe feedbacks.…”

Section: Introductionmentioning

confidence: 99%

Effect of warming and drought on grassland microbial communities

et al. 2011

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The soil microbiome is responsible for mediating key ecological processes; however, little is known about its sensitivity to climate change. Observed increases in global temperatures and alteration to rainfall patterns, due to anthropogenic release of greenhouse gases, will likely have a strong influence on soil microbial communities and ultimately the ecosystem services they provide. Therefore, it is vital to understand how soil microbial communities will respond to future climate change scenarios. To this end, we surveyed the abundance, diversity and structure of microbial communities over a 2-year period from a long-term in situ warming experiment that experienced a moderate natural drought. We found the warming treatment and soil water budgets strongly influence bacterial population size and diversity. In normal precipitation years, the warming treatment significantly increased microbial population size 40-150% but decreased diversity and significantly changed the composition of the community when compared with the unwarmed controls. However during drought conditions, the warming treatment significantly reduced soil moisture thereby creating unfavorable growth conditions that led to a 50-80% reduction in the microbial population size when compared with the control. Warmed plots also saw an increase in species richness, diversity and evenness; however, community composition was unaffected suggesting that few phylotypes may be active under these stressful conditions. Our results indicate that under warmed conditions, ecosystem water budget regulates the abundance and diversity of microbial populations and that rainfall timing is critical at the onset of drought for sustaining microbial populations.

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Consequences of More Extreme Precipitation Regimes for Terrestrial Ecosystems

Cited by 1,005 publications

References 65 publications

Aridity threshold in controlling ecosystem nitrogen cycling in arid and semi-arid grasslands

Aridity threshold in controlling ecosystem nitrogen cycling in arid and semi-arid grasslands

Caterpillar abundance and parasitism in a seasonally dry versus wet tropical forest of Panama

Effect of warming and drought on grassland microbial communities

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