Assessing the effects of rainfall reduction on litterfall and the litter layer in phytophysiognomies of the Amazonia–Cerrado transition

Atmospheric circulation change is likely to be the dominant driver of multidecadal rainfall trends in the midlatitudes with climate change this century. This study examines circulation features relevant to southern Australian rainfall in January and July and explores emergent constraints suggested by the intermodel spread and their impact on the resulting rainfall projection in the CMIP5 ensemble. The authors find relationships between models’ bias and projected change for four features in July, each with suggestions for constraining forced change. The features are the strength of the subtropical jet over Australia, the frequency of blocked days in eastern Australia, the longitude of the peak blocking frequency east of Australia, and the latitude of the storm track within the polar front branch of the split jet. Rejecting models where the bias suggests either the direction or magnitude of change in the features is implausible produces a constraint on the projected rainfall reduction for southern Australia. For RCP8.5 by the end of the century the constrained projections are for a reduction of at least 5% in July (with models showing increase or little change being rejected). Rejecting these models in the January projections, with the assumption the bias affects the entire simulation, leads to a rejection of wet and dry outliers.

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Can trophic rewilding reduce the impact of fire in a more flammable world?

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2017.0443 ◽

2018 ◽

Vol 373 (1761) ◽

pp. 20170443 ◽

Cited By ~ 17

Author(s):

Christopher N. Johnson ◽

Lynda D. Prior ◽

Sally Archibald ◽

Helen M. Poulos ◽

Andrew M. Barton ◽

...

Keyword(s):

Fire Regimes ◽

Ground Vegetation ◽

Litter Layer ◽

Theme Issue ◽

Large Herbivores ◽

Plant Matter ◽

The World ◽

Large Animals ◽

In Fire ◽

The Impact

Large vertebrates affect fire regimes in several ways: by consuming plant matter that would otherwise accumulate as fuel; by controlling and varying the density of vegetation; and by engineering the soil and litter layer. These processes can regulate the frequency, intensity and extent of fire. The evidence for these effects is strongest in environments with intermediate rainfall, warm temperatures and graminoid-dominated ground vegetation. Probably, extinction of Quaternary megafauna triggered increased biomass burning in many such environments. Recent and continuing declines of large vertebrates are likely to be significant contributors to changes in fire regimes and vegetation that are currently being experienced in many parts of the world. To date, rewilding projects that aim to restore large herbivores have paid little attention to the value of large animals in moderating fire regimes. Rewilding potentially offers a powerful tool for managing the risks of wildfire and its impacts on natural and human values. This article is part of the theme issue ‘Trophic rewilding: consequences for ecosystems under global change’.

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The surface CO2 gradient and pore-space storage flux in a high-porosity litter layer

Tellus B ◽

10.3402/tellusb.v56i4.16449 ◽

2004 ◽

Vol 56 (4) ◽

pp. 312-321 ◽

Cited By ~ 5

Author(s):

Adam I. Hirsch ◽

Susan E.: Trumbore ◽

Michael L. Goulden

Keyword(s):

Pore Space ◽

High Porosity ◽

Litter Layer ◽

Storage Flux

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Are vegetation–soil systems drivers of ecosystem carbon contents along an elevational gradient in a highland temperate forest?

Canadian Journal of Forest Research ◽

10.1139/cjfr-2018-0245 ◽

2019 ◽

Vol 49 (3) ◽

pp. 296-304 ◽

Cited By ~ 2

Author(s):

Isela Jasso-Flores ◽

Leopoldo Galicia ◽

Felipe García-Oliva ◽

Angelina Martínez-Yrízar

Keyword(s):

Climate Change ◽

Aboveground Biomass ◽

Soil Depth ◽

Global Climate ◽

Elevational Gradient ◽

Litter Layer ◽

Upward Migration ◽

Soil Carbon Stock ◽

Ecosystem Carbon ◽

Soil Systems

Vegetation–soil systems differentially influence the ecosystem processes related to the carbon cycle, particularly when one tree species is dominant over wide geographic regions that are undergoing climate change. The objective of this study was to quantify the stocks of ecosystem carbon in three vegetation–soil systems along a highland elevational gradient in central Mexico. The vegetation–soil systems, from lower to higher elevation, were dominated by Alnus jorullensis Kunth, Abies religiosa (Kunth) Schltdl. & Cham., and Pinus hartwegii Lindl., respectively. Above- and below-ground tree biomass was determined in each system, along with the litter, coarse woody material, roots, and litterfall. The A. religiosa system had the greatest stock of aboveground biomass carbon (216 ± 31 Mg C·ha−1). The A. jorullensis system had the greatest production of litterfall (3.1 ± 0.08 Mg·ha−1·year−1); however, the carbon content of this litter layer (1.2 ± 0.32 Mg C·ha−1) was lower than that of P. hartwegii (10.1 ± 0.28 Mg C·ha−1). Thus, the litter layer in the A. jorullensis system had markedly the shortest residence time (8 years), suggesting high rates of litter decomposition. The soil carbon stock (at soil depth of 1 m) was greater in A. jorullensis (189 Mg C·ha−1) and P. hartwegii (137 Mg C·ha−1) than in A. religiosa (68 Mg C·ha−1). The A. religiosa and A. jorullensis systems had the highest and lowest total ecosystem C content (301 and 228 Mg C·ha−1, respectively). Upward migration of the A. religiosa system in response to global climate change, however, could cause losses by 2030 of 187 Mg C·ha−1 associated with aboveground biomass.

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Drought and rewetting events enhance nitrate leaching and seepage-mediated translocation of microbes from beech forest soils

10.1101/2020.08.03.234047 ◽

2020 ◽

Author(s):

Markus Krüger ◽

Karin Potthast ◽

Beate Michalzik ◽

Alexander Tischer ◽

Kirsten Küsel ◽

...

Keyword(s):

Forest Soils ◽

Nitrate Leaching ◽

Soil Depth ◽

Groundwater Resources ◽

Beech Forest ◽

Summer Drought ◽

Ammonia Oxidizing Bacteria ◽

Litter Layer ◽

Drought Period ◽

Potential Nitrification

AbstractNitrification in forest soils is often associated with increased leaching of nitrate to deeper soil layers with potential impacts on groundwater resources, further enhanced under scenarios of anthropogenic atmospheric nitrogen deposition and predicted weather extremes. We aimed to disentangle the relationships between soil nitrification potential, seepage-mediated nitrate leaching and the vertical translocation of nitrifiers in soils of a temperate mixed beech forest in central Germany before, during and after the severe summer drought 2018. Leaching of nitrate assessed below the litter layer and in 4, 16 and 30 cm soil depth showed high temporal and vertical variation with maxima at 16 and 30 cm during and after the drought period. Maximum of soil potential nitrification activity of 4.4 mg N kg-1 d-1 only partially coincided with maximum nitrate leaching of 10.5 kg N ha-2. Both ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) were subject to translocation by seepage, and AOB decreased at least by half and AOA increased by one to three orders of magnitude in their abundance in seepage with increasing soil depth. On the level of the total bacterial population, an increasing trend with depth was also observed for Cand. Patescibacteria while Bacteroidetes were strongly mobilized from the litter layer but poorly transported further down. Despite stable population densities in soil over time, abundances of AOA, AOB and total bacteria in seepage increased by one order of magnitude after the onset of autumn rewetting. Predicted future higher frequency of drought periods in temperate regions may result in more frequent seepage-mediated seasonal flushes of nitrate and bacteria from forest soils. Moreover, the observed translocation patterns point to taxon-specific differences in the susceptibility to mobilization, suggesting that only selected topsoil derived microbial groups are likely to affect subsoil or groundwater microbial communities and their functional potential.

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Litter Ecohydrological Function Characteristics of Three Typical Plant Communities in The Core Area of Five-Hundred-Meter Aperture Spherical Radio Telescope from Guizhou, China

10.21203/rs.3.rs-607783/v1 ◽

2021 ◽

Author(s):

Jianli Zhang ◽

Ting Zhang ◽

Lihua Pu ◽

Lingbin Yan ◽

Guojun Cai ◽

...

Keyword(s):

Water Absorption ◽

Plant Communities ◽

Coniferous Forest ◽

Water Holding Capacity ◽

Litter Layer ◽

Broad Leaved Forest ◽

Maximum Water ◽

And Storage ◽

Water Holding ◽

Leaved Forest

Abstract Taking the litter layer of three typical plant communities (broad-leaved forest, coniferous forest, and shrubs) as the research object, this study analyzed the hydrological function characteristics of the litter layers of different typical plant communities using the indoor immersion method in order to reveal the effects of the traits of the litter layer on the hydrological functions of typical plant communities in the core area. The results showed that: (1) the litter reserve change trend decreased in order as follows: broad-leaved forest (13.31 ± 1.54 t/hm2) > shrubs (12.62 ± 2.34 t/hm2) > coniferous forest (11.36 ± 1.43 t/hm2). The coniferous forest and shrub litter reserves increased significantly with the increase of decomposition degree (F = 19.36, P < 0.01; and F = 9.19, P < 0.01, respectively), while the broad-leaved forest litter reserves decreased first and then increased significantly with the increase of decomposition degree (F = 25.70, P < 0.01); (2) the litter natural moisture content change trends were as follows: shrubs (34.09 ± 4.31 t/hm2) > broad-leaved forest (31.32 ± 1.76 t/hm2) > coniferous forest (29.48 ± 7.02 t/hm2). The change trends of the maximum water-holding capacity, maximum interception amount, maximum interception rate, effective interception amount, and effective interception rate were in descending order as follows: broad-leaved forest > shrubs > coniferous forest. The maximum water-holding capacity, maximum interception amount, and effective interception amount of litter rose with the increase of decomposition degree. The broad-leaved forest community litter layer had the strongest rainfall interception function and the best hydrological service functions. The interception function was stronger with the increase of the decomposition degree of the litter layer; (3) the water-holding and water-releasing capacity variation of the litter layers manifested as reversed “J” features for the three typical plant communities. The water-holding capacity of different plant community litter layers (Qct) was significantly positively correlated with time (t) (P < 0.01), and the equation was Qct = b + alnt, whereas the water-releasing capacity of different plant community litter layers (Qst) was significantly positively correlated with time (t) (P < 0.01), and the equation was Qst = a t b; and (4) the water absorption and release rates of the litter layers had four periods. The water absorption rate (v) was significantly negatively correlated with time (t) (P < 0.01), and the equation was v = a t− b, while the water release rate was the same. The water absorption and release rates differed by one order of magnitude in the first 5 min, exhibiting the greatest regulation and storage function, while the rate differed by only 2.1–4.5 times during the last three periods. This shows that the litter layer has the strongest rainfall regulation and storage function for only a short period of time before declining.

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Does Mixing Tree Species Affect Water Storage Capacity of the Forest Floor? Laboratory Test of Pine-Oak and Fir-Beech Litter Layers

Forests ◽

10.3390/f12121674 ◽

2021 ◽

Vol 12 (12) ◽

pp. 1674

Author(s):

Anna Ilek ◽

Małgorzata Szostek ◽

Anna Mikołajczyk ◽

Marta Rajtar

Keyword(s):

Physical Properties ◽

Bulk Density ◽

Tree Species ◽

Forest Floor ◽

Storage Capacity ◽

Water Storage ◽

Pine Needles ◽

Litter Layer ◽

Water Storage Capacity ◽

Organic Debris

During the last decade, tree species mixing has been widely supported as a silvicultural approach to reduce drought stress. However, little is known on the influence of tree species mixing on physical properties and the water storage capacity of forest soils (including the forest floor). Thus, the study aimed to analyze the effect of mixing pine needles and oak leaves and mixing fir needles and beech leaves on hydro-physical properties of the litter layer during laboratory tests. We used fir-beech and pine-oak litter containing various shares of conifer needles (i.e., 0, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100%) to determine the influence of the needle admixture on bulk density, total porosity, macroporosity, water storage capacity, the amount of water stored in pores between organic debris and the degree of saturation of mixed litter compared to broadleaf litter (oak or beech). We found that the admixture of fir needles increased the bulk density of litter from 7.9% with a 5% share of needles to 55.5% with a 50% share (compared to pure beech litter), while the share of pine needles < 40% caused a decrease in bulk density by an average of 3.0–11.0% (compared to pure oak litter). Pine needles decreased the water storage capacity of litter by about 13–14% with the share of needles up to 10% and on average by 28% with the 40 and 50% shares of pine needles in the litter layer. Both conifer admixtures reduced the amount of water stored in the pores between organic debris (pine needles more than fir needles).

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Plant, fungal, bacterial, and nitrogen interactions in the litter layer of a native Patagonian forest

PeerJ ◽

10.7717/peerj.4754 ◽

2018 ◽

Vol 6 ◽

pp. e4754 ◽

Cited By ~ 7

Author(s):

Lucía Vivanco ◽

Nicolás Rascovan ◽

Amy T. Austin

Keyword(s):

Bacterial Community ◽

Litter Decomposition ◽

Plant Species ◽

Tree Species ◽

Microbial Interactions ◽

N Addition ◽

Litter Layer ◽

Species Identity ◽

Single Tree ◽

Stimulation Of

Plant–microbial interactions in the litter layer represent one of the most relevant interactions for biogeochemical cycling as litter decomposition is a key first step in carbon and nitrogen turnover. However, our understanding of these interactions in the litter layer remains elusive. In an old-growth mixed Nothofagus forest in Patagonia, we studied the effects of single tree species identity and the mixture of three tree species on the fungal and bacterial composition in the litter layer. We also evaluated the effects of nitrogen (N) addition on these plant–microbial interactions. In addition, we compared the magnitude of stimulation of litter decomposition due to home field advantage (HFA, decomposition occurs more rapidly when litter is placed beneath the plant species from which it had been derived than beneath a different plant species) and N addition that we previously demonstrated in this same forest, and used microbial information to interpret these results. Tree species identity had a strong and significant effect on the composition of fungal communities but not on the bacterial community of the litter layer. The microbial composition of the litter layer under the tree species mixture show an averaged contribution of each single tree species. N addition did not erase the plant species footprint on the fungal community, and neither altered the bacterial community. N addition stimulated litter decomposition as much as HFA for certain tree species, but the mechanisms behind N and HFA stimulation may have differed. Our results suggest that stimulation of decomposition from N addition might have occurred due to increased microbial activity without large changes in microbial community composition, while HFA may have resulted principally from plant species’ effects on the litter fungal community. Together, our results suggest that plant–microbial interactions can be an unconsidered driver of litter decomposition in temperate forests.

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