Carbon and nitrogen in the topsoils of Inceptisols and Mollisols under native sage scrub and non-native grasslands in southern California

Caspi, Tal; Estrada, Leo; Dowling, Anna V.; Su, Erin; Leshchinskiy, Maxim; Cavalcanti, André R. O.; Crane, Edward J.; Robins, Colin R.; Meyer, Wallace M.

doi:10.1016/j.geodrs.2018.e00172

Cited by 10 publications

(40 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First, we obtained an intact soil clod from the mineral soil surface (A horizon) for calculating bulk density (Burt, ). We slightly modified the clod method used in Caspi et al () to decrease the number of times each soil clod is dipped in resin and to better account for hairnet weight. The final equation used is below (where D is density and W is weight).

D_{soil} = \frac{[((W_{dip1} - (W_{dip2} - W_{dip1})) - W_{hairnet}) \times (1 - (\frac{W_{dip2} - W_{oven}}{W_{dip2}}))] - W_{rocks}}{Volume} .

…”

Section: Methodsmentioning

confidence: 99%

“…Both studies found decreased soil C concentrations in non‐native grasslands compared to adjacent sage scrub habitats. While Wheeler et al () found decreased N in soil under type‐converted non‐native grasslands, Caspi et al () did not find significant soil N differences between habitat types, suggesting that N storage may be particularly influenced by interannual variation in environmental conditions. Caspi et al () also suggest that C storage capacities vary along spatial gradients, with coastal sites having higher storage ability than inland sites.…”

Section: Introductionmentioning

confidence: 94%

“…While Wheeler et al () found decreased N in soil under type‐converted non‐native grasslands, Caspi et al () did not find significant soil N differences between habitat types, suggesting that N storage may be particularly influenced by interannual variation in environmental conditions. Caspi et al () also suggest that C storage capacities vary along spatial gradients, with coastal sites having higher storage ability than inland sites. These findings pose serious implications for regional carbon storage ability under increasing non‐native grass invasion, but our understanding of the mechanisms driving these processes remains limited.…”

Section: Introductionmentioning

confidence: 94%

“…Because of the competitive exclusion of grasses and alteration of the soil microbial community, soil C and N storage in areas dominated by invasive mustards could differ from areas dominated by Bromus species. Despite this possibility, previous studies investigating type‐conversion have not differentiated between invasive cover dominated by non‐native forbs like Brassica and invasive habitat composed mostly of non‐native grasses (Caspi et al, ; Matsuda et al, ; Suarez, Bolger, & Case, ; Talluto & Suding, ).…”

Section: Introductionmentioning

confidence: 98%

“…While type‐conversion is a key process in terrestrial accounting of soil C and N, other factors must also be included in regional modeling efforts. Variability in soil taxonomy, structure, and soil density influences nutrient storage capacity across the landscape and can have significant effects across small distances (Caspi et al, ). Additionally, soil microbes play critical roles as drivers of biogeochemical cycling (Fierer et al, ), and differences between microbial assemblages between sage scrub and non‐native grassland habitats may have significant functional implications (Caspi et al, ; Dickens et al, ; Hawkes, Wren, Herman, & Firestone, ; Sigüenza, Crowley, & Allen, ).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Impacts of invasive annuals on soil carbon and nitrogen storage in southern California depend on the identity of the invader

Caspi

Hartz

Villa

et al. 2019

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

Non‐native plant invasions can alter nutrient cycling processes and contribute to global climate change. In southern California, California sage scrub (hereafter sage scrub), a native shrub‐dominated habitat type in lowland areas, has decreased to <10% of its original distribution. Postdisturbance type‐conversion to non‐native annual grassland, and increasingly to mustard‐dominated invasive forbland, is a key contributor to sage scrub loss. To better understand how type‐conversion by common invasive annuals impacts carbon (C) and nitrogen (N) storage in surface soils, we examined how the identity of the invader (non‐native grasses, Bromus spp.; and non‐native forbs, Brassica nigra ), microbial concentrations, and soil properties interact to influence soil nutrient storage in adjacent native and invasive habitat types at nine sites along a coast to inland gradient. We found that the impact of type‐conversion on nutrient storage was contingent upon the invasive plant type. Sage scrub soils stored more C and N than non‐native grasslands, whereas non‐native forblands had nutrient storage similar to or higher than sage scrub. We calculate that >940 t C km −2 and >60 t N km −2 are lost when sage scrub converts to grass‐dominated habitat, demonstrating that grass invasions are significant regional contributors to greenhouse gas emissions. We found that sites with greater total C and N storage were associated with high cation exchange capacities and bacterial concentrations. Non‐native grassland habitat type was a predictor of lower total C, and soil pH, which was greatest in invasive habitats, was a predictor of lower total N. We demonstrate that modeling regional nutrient storage requires accurate classification of habitat type and fine‐scale quantification of cation exchange capacity, pH, and bacterial abundance. Our results provide evidence that efforts to restore and conserve sage scrub enhance nutrient storage, a key ecosystem service reducing atmospheric CO 2 concentrations.

show abstract

D_{soil} = \frac{[((W_{dip1} - (W_{dip2} - W_{dip1})) - W_{hairnet}) \times (1 - (\frac{W_{dip2} - W_{oven}}{W_{dip2}}))] - W_{rocks}}{Volume} .

…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Impacts of invasive annuals on soil carbon and nitrogen storage in southern California depend on the identity of the invader

Caspi

Hartz

Villa

et al. 2019

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

show abstract

Vertebrate herbivory on shrub seedlings in California sage scrub: important but understudied interactions

et al. 2019

View full text Add to dashboard Cite

Soil bacterial assemblage responses to wildfire in low elevation southern California habitats

et al. 2022

View full text Add to dashboard Cite

Understanding how wildfires and modification in plant assemblages interact to influence soil bacteria assemblages is a crucial step in understanding how these disturbances may influence ecosystem structure and function. Here, we resampled soil from three study sites previously surveyed in spring 2016 and 2017 and compared soil bacterial assemblages prior to and six months after (spring 2019) the 2018 Woolsey Fire in the Santa Monica Mountain National Recreation Area using Illumina sequencing of the 16S rRNA gene. All sites harbored both native California sage scrub and a non-native (grassland or forbland) habitat, allowing us to examine how fire influenced bacterial assemblages in common southern California habitats. Most results contrasted with our a-priori hypotheses: (1) richness and diversity increased following the fire, (2) heat/drought resistant and sensitive bacteria did not show consistent and differing patterns by increasing and decreasing, respectively, in relative abundance after the fire, and (3) bacterial assemblage structure was only minimally impacted by fire, with no differences being found between 2017 (pre-fire) and 2019 (post-fire) in three of the six habitats sampled. As sage scrub and non-native grasslands consistently harbored unique bacterial assemblages both before and following the fire, modifications in plant compositions will likely have legacy effects on these soils that persist even after a fire. Combined, our results demonstrate that bacterial assemblages in southern California habitats are minimally affected by fire. Because direct impacts of fire are limited, but indirect impacts, e.g., modifications in plant compositions, are significant, plant restoration efforts following a fire should strive to revegetate sage scrub areas to prevent legacy changes in bacterial composition.

show abstract

Carbon and nitrogen in the topsoils of Inceptisols and Mollisols under native sage scrub and non-native grasslands in southern California

Cited by 10 publications

References 42 publications

Impacts of invasive annuals on soil carbon and nitrogen storage in southern California depend on the identity of the invader

Impacts of invasive annuals on soil carbon and nitrogen storage in southern California depend on the identity of the invader

Vertebrate herbivory on shrub seedlings in California sage scrub: important but understudied interactions

Soil bacterial assemblage responses to wildfire in low elevation southern California habitats

Contact Info

Product

Resources

About