A Multiscale, Hierarchical Model of Pulse Dynamics in Arid-Land Ecosystems

Collins, Scott L.; Belnap, Jayne; Grimm, Nancy B.; Rudgers, Jenn; Dahm, Clifford N.; D’Odorico, Paolo; Litvak, M. E.; Natvig, Donald O.; Peters, Debra P. C.; Pockman, William T.; Sinsabaugh, Robert L.; Wolf, Blair O.

doi:10.1146/annurev-ecolsys-120213-091650

Cited by 185 publications

(179 citation statements)

References 127 publications

(147 reference statements)

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“…Application of above-mentioned methods for assessing DSR in arid and semi-arid regions has met a variety of challenges, primarily due to the fact that precipitation events often happen in the form of short pulses with highly variable intensity (Collins et al, 2014). The intermittent and unpredictable characteristics of precipitation events led to highly variable moisture and nutrient levels in the soils (Beatley, 1974;Huxman et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Is annual recharge coefficient a valid concept in arid and semi-arid regions?

Cheng

Zhan

Yang

et al. 2017

Hydrol. Earth Syst. Sci.

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Abstract. Deep soil recharge (DSR) (at depth greater than 200 cm) is an important part of water circulation in arid and semi-arid regions. Quantitative monitoring of DSR is of great importance to assess water resources and to study water balance in arid and semi-arid regions. This study used a typical bare land on the eastern margin of Mu Us Sandy Land in the Ordos Basin of China as an example to illustrate a new lysimeter method of measuring DSR to examine if the annual recharge coefficient is valid or not in the study site, where the annual recharge efficient is the ratio of annual DSR over annual total precipitation. Positioning monitoring was done on precipitation and DSR measurements underneath mobile sand dunes from 2013 to 2015 in the study area. Results showed that use of an annual recharge coefficient for estimating DSR in bare sand land in arid and semi-arid regions is questionable and could lead to considerable errors. It appeared that DSR in those regions was influenced by precipitation pattern and was closely correlated with spontaneous strong precipitation events (with precipitation greater than 10 mm) other than the total precipitation. This study showed that as much as 42 % of precipitation in a single strong precipitation event can be transformed into DSR. During the observation period, the maximum annual DSR could make up 24.33 % of the annual precipitation. This study provided a reliable method of estimating DSR in sandy areas of arid and semi-arid regions, which is valuable for managing groundwater resources and ecological restoration in those regions. It also provided strong evidence that the annual recharge coefficient was invalid for calculating DSR in arid and semi-arid regions. This study shows that DSR is closely related to the strong precipitation events, rather than to the average annual precipitation, as well as the precipitation patterns.

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Section: Introductionmentioning

confidence: 99%

Is annual recharge coefficient a valid concept in arid and semi-arid regions?

Cheng

Zhan

Yang

et al. 2017

Hydrol. Earth Syst. Sci.

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“…The diversity of findings suggest that the consumereresourceeprimary producer relationship is nuanced in arid and semi-arid ecosystems, thus requiring consideration of interactions between herbivory and other abiotic factors, such as soil resources and light availability (Borer et al, 2014). Mean annual precipitation controls aridland primary production at large scales (Muldavin et al, 2008), but rainfall variability and landscape properties can lead to complex interactions between producer and consumer populations (Collins et al, 2014;McCluney et al, 2012). For example, as in other systems, both desert plant biomass and herbivore abundance increase with precipitation, but consumer population sizes lag behind primary producers as they are more closely related to the previous years' production (B aez et al, 2006;Brown and Ernest, 2002;Chase et al, 2000;Ernest et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Top-down vs. bottom-up regulation of herbaceous primary production and composition in an arid, urbanizing ecosystem

Davis

Cook

Collins

et al. 2015

Journal of Arid Environments

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“…(ii) The effect of enhanced interannual precipitation variation increases through time. The duration of increased precipitation variability periods may lead to hierarchical ecosystem responses (19). We expect that physiological responses Significance Although increased climatic variability resulting from climate change has been accepted by the scientific community and forms part of the public narrative, studies of the effect of climatic variability on ecosystems have received much less attention than effects of changes in the mean state of climate.…”

mentioning

confidence: 99%

Enhanced precipitation variability decreases grass- and increases shrub-productivity

Gherardi

Sala

2015

Proc. Natl. Acad. Sci. U.S.A.

238

191

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Although projections of precipitation change indicate increases in variability, most studies of impacts of climate change on ecosystems focused on effects of changes in amount of precipitation, overlooking precipitation variability effects, especially at the interannual scale. Here, we present results from a 6-y field experiment, where we applied sequences of wet and dry years, increasing interannual precipitation coefficient of variation while maintaining a precipitation amount constant. Increased precipitation variability significantly reduced ecosystem primary production. Dominant plantfunctional types showed opposite responses: perennial-grass productivity decreased by 81%, whereas shrub productivity increased by 67%. This pattern was explained by different nonlinear responses to precipitation. Grass productivity presented a saturating response to precipitation where dry years had a larger negative effect than the positive effects of wet years. In contrast, shrubs showed an increasing response to precipitation that resulted in an increase in average productivity with increasing precipitation variability. In addition, the effects of precipitation variation increased through time. We argue that the differential responses of grasses and shrubs to precipitation variability and the amplification of this phenomenon through time result from contrasting root distributions of grasses and shrubs and competitive interactions among plant types, confirmed by structural equation analysis. Under drought conditions, grasses reduce their abundance and their ability to absorb water that then is transferred to deep soil layers that are exclusively explored by shrubs. Our work addresses an understudied dimension of climate change that might lead to widespread shrub encroachment reducing the provisioning of ecosystem services to society.C limate-change simulations project increases in precipitation variability as a result of global warming (1-3). The frequency of large precipitation events is expected to increase (3, 4), even in regions where precipitation will decrease (5). Similarly, the occurrence of wet days will decrease, resulting in a highly variable climate with enhanced probabilities of drought and heavy rainfall (5). Precipitation change will occur at intra-, interannual, and decadal scales. Mechanisms explaining such changes differ among temporal scales. At short-time scales, high precipitation variation results from the increased water-holding capacity of a warmer atmosphere that yields large rainfall events interspaced with droughts (6). At the interannual and decadal scales, climate change results in enhanced precipitation variability resulting from changes in atmospheric circulation that affect multiyear rainfall patterns (7).Although precipitation variability changes are part of the public narrative (8) and motivated a special Intergovernmental Panel on Climate Change (IPCC) report on extreme events (9), our understanding of the effect of climate variability on the carbon cycle in grasslands is still weak (10). A...

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A Multiscale, Hierarchical Model of Pulse Dynamics in Arid-Land Ecosystems

Cited by 185 publications

References 127 publications

Is annual recharge coefficient a valid concept in arid and semi-arid regions?

Is annual recharge coefficient a valid concept in arid and semi-arid regions?

Top-down vs. bottom-up regulation of herbaceous primary production and composition in an arid, urbanizing ecosystem

Enhanced precipitation variability decreases grass- and increases shrub-productivity

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