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Earth harbours an extraordinary plant phenotypic diversity1 that is at risk from ongoing global changes2,3. However, it remains unknown how increasing aridity and livestock grazing pressure-two major drivers of global change4-6-shape the trait covariation that underlies plant phenotypic diversity1,7. Here we assessed how covariation among 20 chemical and morphological traits responds to aridity and grazing pressure within global drylands. Our analysis involved 133,769 trait measurements spanning 1,347 observations of 301 perennial plant species surveyed across 326 plots from 6 continents. Crossing an aridity threshold of approximately 0.7 (close to the transition between semi-arid and arid zones) led to an unexpected 88% increase in trait diversity. This threshold appeared in the presence of grazers, and moved toward lower aridity levels with increasing grazing pressure. Moreover, 57% of observed trait diversity occurred only in the most arid and grazed drylands, highlighting the phenotypic uniqueness of these extreme environments. Our work indicates that drylands act as a global reservoir of plant phenotypic diversity and challenge the pervasive view that harsh environmental conditions reduce plant trait diversity8-10. They also highlight that many alternative strategies may enable plants to cope with increases in environmental stress induced by climate change and land-use intensification.
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A significant fraction of Earth's ecosystems undergoes periodic wet-dry alternating transitional states. These globally distributed water-driven transitional ecosystems, such as intermittent rivers and coastal shorelines, have traditionally been studied as two distinct entities, whereas they constitute a single, interconnected meta-ecosystem. This has resulted in a poor conceptual and empirical understanding of water-driven transitional ecosystems. Here, we develop a conceptual framework that places the temporal availability of water as the core driver of biodiversity and functional patterns of transitional ecosystems at the global scale. Biological covers (e.g., aquatic biofilms and biocrusts) serve as an excellent model system thriving in both aquatic and terrestrial states, where their succession underscores the intricate interplay between these two states. The duration, frequency, and rate of change of wet-dry cycles impose distinct plausible scenarios where different types of biological covers can occur depending on their desiccation/hydration resistance traits. This implies that the distinct eco-evolutionary potential of biological covers, represented by their trait profiles, would support different functions while maintaining similar multifunctionality levels. By embracing multiple alternating transitional states as interconnected entities, our approach can help to better understand and manage global change impacts on biodiversity and multifunctionality in water-driven transitional ecosystems, while providing new avenues for interdisciplinary studies.
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Biodiversidade , Ecossistema , BiofilmesRESUMO
Perennial plants create productive and biodiverse hotspots, known as fertile islands, beneath their canopies. These hotspots largely determine the structure and functioning of drylands worldwide. Despite their ubiquity, the factors controlling fertile islands under conditions of contrasting grazing by livestock, the most prevalent land use in drylands, remain virtually unknown. Here we evaluated the relative importance of grazing pressure and herbivore type, climate and plant functional traits on 24 soil physical and chemical attributes that represent proxies of key ecosystem services related to decomposition, soil fertility, and soil and water conservation. To do this, we conducted a standardized global survey of 288 plots at 88 sites in 25 countries worldwide. We show that aridity and plant traits are the major factors associated with the magnitude of plant effects on fertile islands in grazed drylands worldwide. Grazing pressure had little influence on the capacity of plants to support fertile islands. Taller and wider shrubs and grasses supported stronger island effects. Stable and functional soils tended to be linked to species-rich sites with taller plants. Together, our findings dispel the notion that grazing pressure or herbivore type are linked to the formation or intensification of fertile islands in drylands. Rather, our study suggests that changes in aridity, and processes that alter island identity and therefore plant traits, will have marked effects on how perennial plants support and maintain the functioning of drylands in a more arid and grazed world.
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Herbivoria , Solo , Solo/química , Plantas , Ecossistema , Clima Desértico , AnimaisRESUMO
Background: Stereotactic radiosurgery (SRS) has supplanted whole brain radiotherapy (WBRT) as standard-of-care adjuvant treatment following surgery for brain metastasis (BrM). Concomitant with the adoption of adjuvant SRS, a new pattern of failure termed "Pachymeningeal failure" (PMF) has emerged. Methods: We reviewed a prospective registry of 264 BrM patients; 145 and 119 were treated adjuvantly with WBRT and SRS, respectively. The Cox proportional hazards model was used to identify variables correlating to outcomes. Outcomes were calculated using the cumulative incidence (CI) method. Univariate (UVA) and multivariate analyses (MVA) were done to identify factors associated with PMF. Results: CI of PMF was 2 % and 18 % at 12 months, and 2 % and 23 % at 24 months for WRBT and SRS, respectively (p < 0.001). The CI of classic leptomeningeal disease (LMD) was 3 % and 4 % at 12 months, and 6 % and 6 % at 24 months for WBRT and SRS, respectively (P = 0.67). On UVA, adjuvant SRS [HR 9.75 (3.43-27.68) (P < 0.001)]; preoperative dural contact (PDC) [HR 6.78 (1.64-28.10) (P = 0.008)]; GPA score [HR 1.64 (1.11-2.42) (P = 0.012)]; and lung EGFR/ALK status [HR 3.11 (1.02-9.45) (P = 0.045)]; were associated with PMF risk. On MVA, adjuvant SRS [HR 8.15 (2.69-24.7) (P < 0.001)]; and PDC [HR 6.28 (1.51-26.1) (P = 0.012)] remained associated with PMF. Conclusions: Preoperative dural contact and adjuvant SRS instead of adjuvant WBRT were associated with an increased risk of PMF. Strategies to improve pachymeningeal radiation coverage to sterilize at risk pachymeninges should be investigated.
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Introduction: Soil bacteria play a crucial role in the terrestrial nitrogen (N) cycle by fixing atmospheric N2, and this process is influenced by both biotic and abiotic factors. The diversity of N2-fixing bacteria (NFB) directly reflects the efficiency of soil N fixation, and the diversity of NFB in degraded alpine meadow soil may change with different N fertilizing levels and varied slopes. However, how N addition affects the diversity of NFB in degraded alpine meadows, and whether this influence varies with slope, remain poorly understood. Methods: We conducted an N addition field experiment at three levels (2, 5, and 10 g N·m-2·a-1) to study the effects of N addition on soil NFB diversity on two different slopes in a degraded meadow on the Tibetan Plateau. Results: There were significant differences in the dominant bacterial species between the two slopes. The Chao1 index, species richness, and beta diversity of NFB did not differ significantly between slopes, but the Shannon index did. Interestingly, N addition had no effect on the diversity of NFB or the abundance of dominant bacteria. However, we did observe a significant change in some low-abundance NFB. The community composition and diversity of NFB were significantly positively correlated with slope and soil physicochemical properties (e.g., total potassium, pH, and total nitrogen). Conclusions: Our study highlights the variation in NFB communities among different slopes in degraded alpine meadows and their resilience to exogenous N addition. Our results also underscore the importance of considering the effects of micro-topography on soil microbial communities in future studies of alpine ecosystems.
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BACKGROUND: Pachymeningeal disease (PMD) is a newly recognized pattern of brain metastasis (BrM) failure that specifically occurs following surgery with adjuvant stereotactic radiosurgery (SRS) and has unique prognostic implications relative to leptomeningeal disease (LMD). Here, we report its prevalence, prognostic implications, and associated risk factors. METHODS: A literature search was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses on PUBMED and Cochrane from January 2000 to June 2023. RESULTS: We identified 12 studies that included a total of 3992 BrM patients, 659 (16.5%) of whom developed meningeal disease (MD) following surgery plus adjuvant SRS, including either PMD or LMD. The mean prevalence of MD across studies was 20.9% (7.9-38.0%), with PMD accounting for 54.6% of this prevalence and LMD comprising the remaining 45.4%. Mean of the median overall survivals following diagnosis of PMD and LMD was 10.6 months and 3.7 months p = 0.007, respectively, a significant difference. Only 2 risk factors for PMD were reported in ≥ 2 studies and also identified as statistically significant per our meta-analysis: infratentorial location and controlled systemic disease status. CONCLUSION: While PMD has a superior prognosis to LMD, it is nevertheless a critical oncologic event associated with significant mortality and remains poorly recognized. PMD is predominantly observed in patients with controlled systemic disease status and infratentorial location. Future treatment strategies should focus on reducing surgical seeding and sterilizing surgical cavities.
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Neoplasias Encefálicas , Neoplasias Meníngeas , Radiocirurgia , Humanos , Neoplasias Meníngeas/epidemiologia , Neoplasias Meníngeas/terapia , Neoplasias Encefálicas/cirurgia , Prognóstico , Fatores de Risco , Radiocirurgia/efeitos adversos , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Ecological theory posits that temporal stability patterns in plant populations are associated with differences in species' ecological strategies. However, empirical evidence is lacking about which traits, or trade-offs, underlie species stability, especially across different biomes. We compiled a worldwide collection of long-term permanent vegetation records (greater than 7000 plots from 78 datasets) from a large range of habitats which we combined with existing trait databases. We tested whether the observed inter-annual variability in species abundance (coefficient of variation) was related to multiple individual traits. We found that populations with greater leaf dry matter content and seed mass were more stable over time. Despite the variability explained by these traits being low, their effect was consistent across different datasets. Other traits played a significant, albeit weaker, role in species stability, and the inclusion of multi-variate axes or phylogeny did not substantially modify nor improve predictions. These results provide empirical evidence and highlight the relevance of specific ecological trade-offs, i.e. in different resource-use and dispersal strategies, for plant populations stability across multiple biomes. Further research is, however, necessary to integrate and evaluate the role of other specific traits, often not available in databases, and intraspecific trait variability in modulating species stability.
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Ecossistema , Plantas , Filogenia , Sementes , Fenótipo , Folhas de PlantaRESUMO
Solitary plasmacytoma is an uncommon hematologic malignancy characterized by the monoclonal proliferation of abnormal plasma cells in the bone or extramedullary tissues and the absence of other multiple myeloma-defining clinical characteristics. Mostly, solitary extramedullary plasmacytoma (SEP) occurs in the head and neck region, also called solitary extramedullary plasmacytoma of the head and neck (SEPHN). Although the standard of care for SEPHN is not well established, either a surgical approach or localized external beam radiotherapy (EBRT) can be used as a definitive treatment. Due to the high radiosensitivity of SEPHN, EBRT has been associated with adequate therapeutic effects in the management of SEP, with the advantage of being a noninvasive modality that yields high rates of local control with a reasonable toxicity profile. We present a case series of three patients with SEPHN treated with EBRT at our institution with clinical outcomes.
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PURPOSE: Neurosurgery (NS) is an essential modality for large brain metastases (BM). Postoperative stereotactic radiosurgery (SRS) is the standard of care adjuvant treatment. Pachymeningeal failure (PMF) is a newly described entity, distinct from classical leptomeningeal failure (LMF), that is uniquely observed in postoperative patients treated with adjuvant SRS. We sought to identify risk factors for PMF in patients treated with NS + SRS. METHODS: From a prospective registry (2009 to 2021), we identified all patients treated with NS + SRS. Clinical, imaging, pathological, and treatment factors were analyzed. PMF incidence was evaluated using a competing risks model. RESULTS: 144 Patients were identified. The median age was 62 (23-90). PMF occurred in 21.5% (31/144). Female gender [Hazard Ratio (HR) 2.65, p = 0.013], higher Graded Prognostic Assessment (GPA) index (HR 2.4, p < 0.001), absence of prior radiation therapy (HR N/A, p = 0.018), controlled extracranial disease (CED) (HR 3.46, p = 0.0038), and pia/dura contact (PDC) (HR 3.30, p = 0.0053) were associated with increased risk for PMF on univariate analysis. In patients with PDC, wider target volumes correlated with reduced risk of PMF. Multivariate analysis indicated PDC (HR 3.51, p = 0.0053), piecemeal resection (HR 2.38, p = 0.027), and CED (HR 3.97, p = 0.0016) independently correlated with PMF risk. PMF correlated with reduced OS (HR 2.90, p < 0.001) at a lower rate compared to LMF (HR 10.15, p < 0.001). CONCLUSION: PMF correlates with tumor PDC and piecemeal resection in patients treated with NS + SRS. For unclear reasons, it is also associated with CED. In tumors with PDC, wider dural radiotherapy coverage was associated with a lower risk of PMF.
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Neoplasias Encefálicas , Radiocirurgia , Humanos , Masculino , Feminino , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundário , Neoplasias Encefálicas/cirurgia , Complicações Pós-Operatórias , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Resultado do Tratamento , Neoplasias Meníngeas/radioterapia , Neoplasias Meníngeas/secundárioRESUMO
Purpose: Biocrust communities, which are important regulators of multiple ecosystem functions in drylands, are highly sensitive to climate change. There is growing evidence of the negative impacts of warming on the performance of biocrust constituents like lichens in the field. Here, we aim to understand the physiological basis behind this pattern. Methods: Using a unique manipulative climate change experiment, we monitored every 30 minutes and for 9 months the chlorophyll a fluorescence and microclimatic conditions (lichen surface temperature, relative moisture and photosynthetically active radiation) of Psora decipiens, a key biocrust constituent in drylands worldwide. This long-term monitoring resulted in 11,847 records at the thallus-level, which allowed us to evaluate the impacts of ~2.3 °C simulated warming treatment on the physiology of Psora at an unprecedented level of detail. Results: Simulated warming and the associated decrease in relative moisture promoted by this treatment negatively impacted the physiology of Psora, especially during the diurnal period of the spring, when conditions are warmer and drier. These impacts were driven by a mechanism based on the reduction of the length of the periods allowing net photosynthesis, and by declines in Yield and Fv/Fm under simulated warming. Conclusion: Our study reveals the physiological basis explaining observed negative impacts of ongoing global warming on biocrust-forming lichens in the field. The functional response observed could limit the growth and cover of biocrust-forming lichens in drylands in the long-term, negatively impacting in key soil attributes such as biogeochemical cycles, water balance, biological activity and ability of controlling erosion. Supplementary Information: The online version contains supplementary material available at 10.1007/s11104-022-05686-w.
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Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that interactions between grazing pressure, climate, soil, and biodiversity are critical to explain the delivery of fundamental ecosystem services across drylands worldwide. Increasing grazing pressure reduced ecosystem service delivery in warmer and species-poor drylands, whereas positive effects of grazing were observed in colder and species-rich areas. Considering interactions between grazing and local abiotic and biotic factors is key for understanding the fate of dryland ecosystems under climate change and increasing human pressure.
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Biodiversidade , Herbivoria , Gado , Mudança Climática , SoloRESUMO
While biodiversity is expected to enhance multiple ecosystem functions (EFs), the different roles of multiple biodiversity dimensions remain difficult to disentangle without carefully designed experiments. We sowed plant communities with independent levels of functional (FD) and phylogenetic diversities (PD), combined with different levels of fertilization, to investigate their direct and indirect roles on multiple EFs, including plant-related EFs (plant biomass productivity, litter decomposability), soil fertility (organic carbon and nutrient pool variables), soil microbial activity (respiration and nutrient cycling), and an overall multifunctionality. We expected an increase in most EFs in communities with higher values of FD and/or PD via complementarity effects, but also the dominant plant types (using community weighted mean, CWM, independent of FD and PD) via selection effects on several EFs. The results showed strong direct effects of different dimensions of plant functional structure parameters on plant-related EFs, through either CWM or FD, with weak effects of PD. Fertilization had significant effects on one soil microbial activity and indirect effects on the other variables via changes in soil abiotic properties. Dominant plant types and FD showed only indirect effects on soil microbial activity, through litter decomposition and soil abiotic properties, highlighting the importance of cascading effects. This study shows the relevance of complementary dimensions of biodiversity for assessing both direct and cascading effects on multiple EFs.
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Ecossistema , Solo , Solo/química , Filogenia , Plantas , Biodiversidade , Microbiologia do SoloRESUMO
Background: Brain metastasis quantity may be a negative prognostic factor for patients requiring resection of at least one lesion. Methods: We retrospectively reviewed patients who underwent surgical resection of brain metastases from July 2018 to June 2019 at our institution, and examined outcomes including overall survival (OS), progression free survival (PFS), and rates of local failure (LF). Patients were grouped according to the number of metastases at the time of surgery (single vs multiple). Results: We identified 130 patients who underwent surgical resection as the initial treatment modality. At the time of surgery, 87 patients had only one lesion (control) and 43 had multiple (>1). Two-year OS for the entire cohort was 46%, with equal rates in both the multiple metastases group and the control group (P = .335). 2-year PFS was 27%; 21% in the multiple metastases group and 31% in the control group (P = .766). The rate of LF at 2 years was 32%, with equal rates in both the multiple lesion group and control group (P = .889). On univariate analysis, multiplicity was not significantly correlated to OS (HR = 0.80, 95% CI: 0.51-1.26, P = .336), PFS (HR = 1.06, 95% CI: 0.71-1.59, P = .766) or LF (HR = 1.06, 95% CI: 0.57-1.97, P = .840). Multivariate analysis revealed preoperative tumor volume of the resected lesion to be the single correlate for OS (P = .0032) and PFS (P = .0081). Conclusions: Having more than one metastasis does not negatively impact outcomes in patients treated with surgery. In carefully selected patients, especially those with large tumors, surgery should be considered regardless of the total number of lesions.
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BACKGROUND: We sought to identify variates correlating with overall survival (OS) in patients treated with surgery (S) plus adjuvant stereotactic radiosurgery (SRS) versus definitive SRS for large (>4 cc) brain metastases (BrM). METHODS: We used univariate (UVA) and multivariate analyses (MVA) to identify survival correlates among eligible patients identified from a prospective registry and compared definitive SRS to S+ adjuvant SRS cohorts using propensity score-matched analysis (PSMA). Secondary outcomes were measured using the cumulative incidence (CI) method. RESULTS: We identified 364 patients; 127 and 237 were treated with S+SRS and definitive SRS, respectively. On UVA, SRS alone [HR1.73 (1.35,2.22) P < .001), BrM quantity [HR 1.13 (1.06-1.22) (P < .001)]; performance status (PS) [HR 2.78 (1.73-4.46) (P < .001)]; extracranial disease (ECD) [HR 1.82 (1.37,2.40) (P < .001)]; and receipt of systemic treatment after BrM therapy, [HR 0.58 (0.46-073) (P < .001)] correlated with OS. On MVA, SRS alone [HR 1.81 (1.19,2.74) (P < .0054)], SRS target volume [HR 1.03 (1.01,1.06) (P < .0042)], and receipt of systemic treatment [HR 0.68 (0.50,0.93) (P < .015)] correlated with OS. When PSMA was used to balance ECD, BrM quantity, PS, and SRS target volume, SRS alone remained correlated with worsened OS [HR 1.62 (1.20-2.19) (P = 0.0015)]. CI of local failure requiring resection at 12 months was 3% versus 7% for S+SRS and SRS cohorts, respectively [(HR 2.04 (0.89-4.69) (P = .091)]. CI of pachymeningeal failure at 12 months was 16% versus 0% for S+SRS and SRS. CONCLUSION: SRS target volume, receipt of systemic therapies, and treatment with S+SRS instead of definitive SRS correlated with improved survival in patients with large BrM.
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Neoplasias Encefálicas , Radiocirurgia , Humanos , Radiocirurgia/métodos , Estudos Retrospectivos , Neoplasias Encefálicas/secundário , Incidência , Análise MultivariadaRESUMO
Under global change, how biological diversity and ecosystem services are maintained in time is a fundamental question. Ecologists have long argued about multiple mechanisms by which local biodiversity might control the temporal stability of ecosystem properties. Accumulating theories and empirical evidence suggest that, together with different population and community parameters, these mechanisms largely operate through differences in functional traits among organisms. We review potential trait-stability mechanisms together with underlying tests and associated metrics. We identify various trait-based components, each accounting for different stability mechanisms, that contribute to buffering, or propagating, the effect of environmental fluctuations on ecosystem functioning. This comprehensive picture, obtained by combining different puzzle pieces of trait-stability effects, will guide future empirical and modeling investigations.
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Biodiversidade , Ecossistema , FenótipoRESUMO
(1) Background: exposure to heavy metals is associated with adverse health effects and disproportionately impacts low-income communities and communities of color. We carried out a community-based participatory research study to examine the distribution of heavy metal concentrations in the soil and social vulnerabilities to soil heavy metal exposures across Census tracts in Santa Ana, CA. (2) Methods: soil samples (n = 1528) of eight heavy metals including lead (Pb), arsenic (As), manganese (Mn), chromium (Cr), nickel (Ni), copper (Cu), cadmium (Cd), and zinc (Zn) were collected in 2018 across Santa Ana, CA, at a high spatial resolution and analyzed using XRF analysis. Metal concentrations were mapped out and American Community Survey data was utilized to assess metals throughout Census tracts in terms of social and economic variables. Risk assessment was conducted to evaluate carcinogenic and non-carcinogenic risk. (3) Results: concentrations of soil metals varied according to landuse type and socioeconomic factors. Census tracts where the median household income was under $50 000 had 390%, 92.9%, 56.6%, and 54.3% higher Pb, Zn, Cd, and As concentrations compared to high-income counterparts. All Census tracts in Santa Ana showed hazard index >1, implying the potential for non-carcinogenic health effects, and nearly all Census tracts showed a cancer risk above 10-4, implying a greater than acceptable risk. Risk was predominantly driven by childhood exposure. (4) Conclusions: findings inform initiatives related to environmental justice and highlight subpopulations at elevated risk of heavy metal exposure, in turn underscoring the need for community-driven recommendations for policies and other actions to remediate soil contamination and protect the health of residents.
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Metais Pesados , Poluentes do Solo , Censos , China , Cidades , Monitoramento Ambiental , Metais Pesados/análise , Medição de Risco , Solo , Poluentes do Solo/análiseRESUMO
Biocrusts are key drivers of ecosystem functioning in drylands, yet our understanding of how climate change will affect the chemistry of biocrust-forming species and their impacts on carbon (C) and nitrogen (N) cycling is still very limited. Using a manipulative experiment conducted with common biocrust-forming lichens with distinct morphology and chemistry (Buellia zoharyi, Diploschistes diacapsis, Psora decipiens and Squamarina lentigera), we evaluated changes in lichen total and isotopic C and N and several soil C and N variables after 50 months of simulated warming and rainfall reduction. Climate change treatments reduced δ13 C and the C : N ratio in B. zoharyi, and increased δ15 N in S. lentigera. Lichens had species-specific effects on soil dissolved organic N (DON), NH4+ , ß-glucosidase and acid phosphatase activity regardless of climate change treatments, while these treatments changed how lichens affected several soil properties regardless of biocrust species. Changes in thallus δ13 C, N and C : N drove species-specific effects on dissolved organic nitrogen (DON), NH4+ , ß-glucosidase and acid phosphatase activity. Our findings indicate that warmer and drier conditions will alter the chemistry of biocrust-forming lichens, affecting soil nutrient cycling, and emphasize their key role as modulators of climate change impacts in dryland soils.
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Briófitas , Líquens , Ascomicetos , Mudança Climática , Ecossistema , Solo , Microbiologia do SoloRESUMO
The stability of ecological communities is critical for the stable provisioning of ecosystem services, such as food and forage production, carbon sequestration, and soil fertility. Greater biodiversity is expected to enhance stability across years by decreasing synchrony among species, but the drivers of stability in nature remain poorly resolved. Our analysis of time series from 79 datasets across the world showed that stability was associated more strongly with the degree of synchrony among dominant species than with species richness. The relatively weak influence of species richness is consistent with theory predicting that the effect of richness on stability weakens when synchrony is higher than expected under random fluctuations, which was the case in most communities. Land management, nutrient addition, and climate change treatments had relatively weak and varying effects on stability, modifying how species richness, synchrony, and stability interact. Our results demonstrate the prevalence of biotic drivers on ecosystem stability, with the potential for environmental drivers to alter the intricate relationship among richness, synchrony, and stability.
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Plantas/classificação , Sequestro de Carbono , Mudança Climática , Ecossistema , Desenvolvimento Vegetal , Plantas/metabolismo , Solo/químicaRESUMO
BACKGROUND: Lead (Pb) exposure is a problem that disproportionately impacts low-income communities and communities of color. We applied a community-based participatory research approach to assess the distribution of soil Pb concentrations and related social vulnerabilities across Census tracts in Santa Ana, CA. METHODS: Soil Pb samples (n = 1528) were collected by the ¡Plo-NO! Santa Ana! Lead-Free Santa Ana! partnership in 2018 across Santa Ana, CA, at a high spatial resolution and measured using XRF analysis. Pb concentrations were mapped and spatial interpolation was conducted to generate a continuous smoothed map of soil Pb concentrations across the city. American Community Survey data was used to examine Pb across Census tracts based on social and economic factors, and to allow for the development of a Cumulative Risk Index to identify areas at high risk of health impacts. RESULTS: Soil Pb concentrations varied by landuse type and socioeconomic factors. Census tracts with a median household income below $50,000 had over five times higher soil Pb concentrations than high-income Census tracts. Soil samples collected in tertiles with the highest percent children, residents without health insurance, renter-occupied housing units, and lowest percent college educated residents had 90.0%, 96.1%, 75.2%, and 87.0% higher Pb concentrations on average, respectively, compared to their counterparts. Overall, 52.7% of residential samples had Pb concentrations in excess of the 80 ppm California EPA recommendation, and 11 Census tracts were characterized as high risk according to our Cumulative Risk Index. DISCUSSION: This study underscores the need for precautionary measures relating to disturbances of the soil, particularly for areas where children play outside, given children's higher absorption of lead. It also informs environmental justice initiatives and identifies vulnerable subpopulations at greater risk of Pb exposure, thus warranting community-driven recommendations for policies and initiatives to remediate soil Pb and protect public health and health equity.