Transoral flexible laser surgery of the upper aerodigestive tract with blue laser.

PURPOSE: The introduction of fiber-guided lasers was a breakthrough in laryngology practice, opening the path for treating different pathologies with minimally invasive procedures, both in the operating room and in the office. The most recent technology in the area is the blue laser, which combines photoangiolytic and cutting properties, characteristics that make this equipment suitable for its use in upper aerodigestive tract surgery. However, there is not enough experience in this area. The authors present a case series of patients with different pharyngeal, laryngeal, and tracheal pathologies who were treated by means of transoral procedures using fiber-guided blue laser. METHODS: The surgical records of patients with different upper aerodigestive tract pathologies who were treated with fiber-guided blue laser in the operating room, under general anesthesia with jet ventilation or supraglottic ventilation using suspension laryngotracheoscopy techniques between February 2018 and March 2022 were reviewed. RESULTS: A total of 80 surgical interventions in a group of 38 patients were performed. A wide variety of procedures was executed, either using the laser alone or in combination with other techniques to treat different pathologies of the aero-digestive tract safely and effectively, with adequate functional results. CONCLUSIONS: Following all necessary precautions, blue laser is a reliable tool to perform minimally invasive surgeries in the operating room using TOFLS techniques. It can be used alone or in combination with other devices to achieve the desired goals.

Quantitative Representativeness and Constituency of the Long-Term Agroecosystem Research Network and Analysis of Complementarity with Existing Ecological Networks.

Studies conducted at sites across ecological research networks usually strive to scale their results to larger areas, trying to reach conclusions that are valid throughout larger enclosing regions. Network representativeness and constituency can show how well conditions at sampling locations represent conditions also found elsewhere and can be used to help scale-up results over larger regions. Multivariate statistical methods have been used to design networks and select sites that optimize regional representation, thereby maximizing the value of datasets and research. However, in networks created from already established sites, an immediate challenge is to understand how well existing sites represent the range of environments in the whole area of interest. We performed an analysis to show how well sites in the USDA Long-Term Agroecosystem Research (LTAR) Network represent all agricultural working lands within the conterminous United States (CONUS). Our analysis of 18 LTAR sites, based on 15 climatic and edaphic characteristics, produced maps of representativeness and constituency. Representativeness of the LTAR sites was quantified through an exhaustive pairwise Euclidean distance calculation in multivariate space, between the locations of experiments within each LTAR site and every 1 km cell across the CONUS. Network representativeness is from the perspective of all CONUS locations, but we also considered the perspective from each LTAR site. For every LTAR site, we identified the region that is best represented by that particular site-its constituency-as the set of 1 km grid locations best represented by the environmental drivers at that particular LTAR site. Representativeness shows how well the combination of characteristics at each CONUS location was represented by the LTAR sites' environments, while constituency shows which LTAR site was the closest match for each location. LTAR representativeness was good across most of the CONUS. Representativeness for croplands was higher than for grazinglands, probably because croplands have more specific environmental criteria. Constituencies resemble ecoregions but have their environmental conditions "centered" on those at particular existing LTAR sites. Constituency of LTAR sites can be used to prioritize the locations of experimental research at or even within particular sites, or to identify the extents that can likely be included when generalizing knowledge across larger regions of the CONUS. Sites with a large constituency have generalist environments, while those with smaller constituency areas have more specialized environmental combinations. These "specialist" sites are the best representatives for smaller, more unusual areas. The potential of sharing complementary sites from the Long-Term Ecological Research (LTER) Network and the National Ecological Observatory Network (NEON) to boost representativeness was also explored. LTAR network representativeness would benefit from borrowing several NEON sites and the Sevilleta LTER site. Later network additions must include such specialist sites that are targeted to represent unique missing environments. While this analysis exhaustively considered principal environmental characteristics related to production on working lands, we did not consider the focal agronomic systems under study, or their socio-economic context.

The XadA Trimeric Autotransporter Adhesins in Xylella fastidiosa Differentially Contribute to Cell Aggregation, Biofilm Formation, Insect Transmission and Virulence to Plants.

Surface adhesion strategies are widely employed by bacterial pathogens during establishment and systemic spread in their host. A variety of cell-surface appendages such as pili, fimbriae, and afimbrial adhesins are involved in these processes. The phytopathogen Xylella fastidiosa employs several of these structures for efficient colonization of its insect and plant hosts. Among the adhesins encoded in the X. fastidiosa genome, three afimbrial adhesins, XadA1, Hsf/XadA2, and XadA3, are predicted to be trimeric autotransporters with a C-terminal YadA-anchor membrane domain. We analyzed the individual contributions of XadA1, XadA2, and XadA3 to various cellular behaviors both in vitro and in vivo. Using isogenic X. fastidiosa mutants, we found that cell-cell aggregation and biofilm formation were severely impaired in the absence of XadA3. No significant reduction of cell-surface attachment was found with any mutant under flow conditions. Acquisition by insect vectors and transmission to grapevines were reduced in the XadA3 deletion mutant. While the XadA3 mutant was hypervirulent in grapevines, XadA1 or XadA2 deletion mutants conferred lower disease severity than the wild-type strain. This insight of the importance of these adhesive proteins and their individual contributions to different aspects of X. fastidiosa biology should guide new approaches to reduce pathogen transmission and disease development. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Informed consent for suspension microlaryngoscopy: what should we tell the patient? A consensus statement of the European Laryngological Society.

INTRODUCTION: Informed consent for any surgical intervention is necessary, as only well-informed patients can actively participate in the decision-making process about their care, and better understand the likely or potential outcomes of their treatment. No consensus exists on informed consent for suspension microlaryngoscopy (SML). MATERIALS AND METHODS: Informed consent procedures in nine countries on five continents were studied. RESULTS: Several risks can be discerned: risks of SML as procedure, anesthesiologic risks of SML, specific risks of phonosurgery, risks of inadequate glottic exposure or unexpected findings, risks of not treating. SML has recognized potential complications, that can be divided in temporary (minor) complications, and lasting (major) complications. CONCLUSION: SML is a safe procedure with low morbidity, and virtually no mortality. Eleven recommendations are provided.

A comparative genomic analysis of Xanthomonas arboricola pv. juglandis strains reveal hallmarks of mobile genetic elements in the adaptation and accelerated evolution of virulence.

Xanthomonas arboricola pv. juglandis (Xaj) is the most significant aboveground walnut bacterial pathogen. Disease management uses copper-based pesticides which induce pathogen resistance. We examined the genetic repertoire associated with adaptation and virulence evolution in Xaj. Comparative genomics of 32 Xaj strains reveal the possible acquisition and propagation of virulence factors via insertion sequences (IS). Fine-scale annotation revealed a Tn3 transposon (TnXaj417) encoding copper resistance genes acquired by horizontal gene transfer and associated with adaptation and tolerance to metal-based pesticides commonly used to manage pathogens in orchard ecosystems. Phylogenomic analysis reveals IS involvement in acquisition and diversification of type III effector proteins ranging from two to eight in non-pathogenic strains, 16 to 20 in pathogenic strains, besides six other putative effectors with a reduced identity degree found mostly among pathogenic strains. Yersiniabactin, xopK, xopAI, and antibiotic resistance genes are also located near ISs or inside genomic islands and structures resembling composite transposons.

Long-term intubation and high rate of tracheostomy in COVID-19 patients might determine an unprecedented increase of airway stenoses: a call to action from the European Laryngological Society.

INTRODUCTION: The novel Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2, may need intensive care unit (ICU) admission in up to 12% of all positive cases for massive interstitial pneumonia, with possible long-term endotracheal intubation for mechanical ventilation and subsequent tracheostomy. The most common airway-related complications of such ICU maneuvers are laryngotracheal granulomas, webs, stenosis, malacia and, less commonly, tracheal necrosis with tracheo-esophageal or tracheo-arterial fistulae. MATERIALS AND METHODS: This paper gathers the opinions of experts of the Laryngotracheal Stenosis Committee of the European Laryngological Society, with the aim of alerting the medical community about the possible rise in number of COVID-19-related laryngotracheal stenosis (LTS), and the aspiration of paving the way to a more rationale concentration of these cases within referral specialist airway centers. RESULTS: A range of prevention strategies, diagnostic work-up, and therapeutic approaches are reported and framed within the COVID-19 pandemic context. CONCLUSIONS: One of the most important roles of otolaryngologists when encountering airway-related signs and symptoms in patients with previous ICU hospitalization for COVID-19 is to maintain a high level of suspicion for LTS development, and share it with colleagues and other health care professionals. Such a condition requires specific expertise and should be comprehensively managed in tertiary referral centers.

An improved bind-n-seq strategy to determine protein-DNA interactions validated using the bacterial transcriptional regulator YipR.

BACKGROUND: Interactions between transcription factors and DNA lie at the centre of many biological processes including DNA recombination, replication, repair and transcription. Most bacteria encode diverse proteins that act as transcription factors to regulate various traits. Several technologies for identifying protein-DNA interactions at the genomic level have been developed. Bind-n-seq is a high-throughput in vitro method first deployed to analyse DNA interactions associated with eukaryotic zinc-finger proteins. The method has three steps (i) binding protein to a randomised oligonucleotide DNA target library, (ii) deep sequencing of bound oligonucleotides, and (iii) a computational algorithm to define motifs among the sequences. The classical Bind-n-seq strategy suffers from several limitations including a lengthy wet laboratory protocol and a computational algorithm that is difficult to use. We introduce here an improved, rapid, and simplified Bind-n-seq protocol coupled with a user-friendly downstream data analysis and handling algorithm, which has been optimized for bacterial target proteins. We validate this new protocol by showing the successful characterisation of the DNA-binding specificities of YipR (YajQ interacting protein regulator), a well-known transcriptional regulator of virulence genes in the bacterial phytopathogen Xanthomonas campestris pv. campestris (Xcc). RESULTS: The improved Bind-n-seq approach identified several DNA binding motif sequences for YipR, in particular the CCCTCTC motif, which were located in the promoter regions of 1320 Xcc genes. Informatics analysis revealed that many of these genes regulate functions associated with virulence, motility, and biofilm formation and included genes previously found involved in virulence. Additionally, electromobility shift assays show that YipR binds to the promoter region of XC_2633 in a CCCTCTC motif-dependent manner. CONCLUSION: We present a new and rapid Bind-n-seq protocol that should be useful to investigate DNA-binding proteins in bacteria. The analysis of YipR DNA binding using this protocol identifies a novel DNA sequence motif in the promoter regions of target genes that define the YipR regulon.

High-Quality Draft Genome Sequence Resources of Eight Xylella fastidiosa Strains Isolated from Citrus, Coffee, Plum, and Hibiscus in South America.

Xylella fastidiosa subsp. pauca, once confined to South America and infecting mainly citrus and coffee plants, has been found to be associated with other hosts and in other geographic regions. We present high-quality draft genome sequences of X. fastidiosa subsp. pauca strains J1a12, B111, U24D, and XRB isolated from citrus plants in Brazil, strain Fb7 isolated from a citrus plant in Argentina and strains 3124, Pr8x, and Hib4 isolated, respectively, from coffee, plum, and hibiscus plants in Brazil. Sequencing was performed using Roche 454-GS FLX, MiSeq-Illumina or Pacific Biosciences platforms. These high-quality genome assemblies will be useful for further studies about the genomic diversity, evolution, and biology of X. fastidiosa.

Targeting of cathepsin S reduces cystic fibrosis-like lung disease.

Cathepsin S (CatS) is upregulated in the lungs of patients with cystic fibrosis (CF). However, its role in CF lung disease pathogenesis remains unclear.In this study, ß-epithelial Na+ channel-overexpressing transgenic (ßENaC-Tg) mice, a model of CF-like lung disease, were crossed with CatS null (CatS-/-) mice or treated with the CatS inhibitor VBY-999.Levels of active CatS were elevated in the lungs of ßENaC-Tg mice compared with wild-type (WT) littermates. CatS-/-ßENaC-Tg mice exhibited decreased pulmonary inflammation, mucus obstruction and structural lung damage compared with ßENaC-Tg mice. Pharmacological inhibition of CatS resulted in a significant decrease in pulmonary inflammation, lung damage and mucus plugging in the lungs of ßENaC-Tg mice. In addition, instillation of CatS into the lungs of WT mice resulted in inflammation, lung remodelling and upregulation of mucin expression. Inhibition of the CatS target, protease-activated receptor 2 (PAR2), in ßENaC-Tg mice resulted in a reduction in airway inflammation and mucin expression, indicating a role for this receptor in CatS-induced lung pathology.Our data indicate an important role for CatS in the pathogenesis of CF-like lung disease mediated in part by PAR2 and highlight CatS as a therapeutic target.

Time dependent expression of the blood biomarkers EIF2D and TOX in patients with schizophrenia.

BACKGROUND: During last years, there has been an intensive search for blood biomarkers in schizophrenia to assist in diagnosis, prognosis and clinical management of the disease. METHODS: In this study, we first conducted a weighted gene coexpression network analysis to address differentially expressed genes in peripheral blood from patients with chronic schizophrenia (n = 30) and healthy controls (n = 15). The discriminating performance of the candidate genes was further tested in an independent cohort of patients with first-episode schizophrenia (n = 124) and healthy controls (n = 54), and in postmortem brain samples (cingulate and prefrontal cortices) from patients with schizophrenia (n = 34) and healthy controls (n = 35). RESULTS: The expression of the Eukaryotic Translation Initiation Factor 2D (EIF2D) gene, which is involved in protein synthesis regulation, was increased in the chronic patients of schizophrenia. On the contrary, the expression of the Thymocyte Selection-Associated High Mobility Group Box (TOX) gene, involved in immune function, was reduced. EIF2D expression was also altered in first-episode schizophrenia patients, but showing reduced levels. Any of the postmortem brain areas studied did not show differences of expression of both genes. CONCLUSIONS: EIF2D and TOX are putative blood markers of chronic patients of schizophrenia, which expression change from the onset to the chronic disease, unraveling new biological pathways that can be used for the development of new intervention strategies in the diagnosis and prognosis of schizophrenia disease.

Ecosystem resilience despite large-scale altered hydroclimatic conditions.

Climate change is predicted to increase both drought frequency and duration, and when coupled with substantial warming, will establish a new hydroclimatological model for many regions. Large-scale, warm droughts have recently occurred in North America, Africa, Europe, Amazonia and Australia, resulting in major effects on terrestrial ecosystems, carbon balance and food security. Here we compare the functional response of above-ground net primary production to contrasting hydroclimatic periods in the late twentieth century (1975-1998), and drier, warmer conditions in the early twenty-first century (2000-2009) in the Northern and Southern Hemispheres. We find a common ecosystem water-use efficiency (WUE(e): above-ground net primary production/evapotranspiration) across biomes ranging from grassland to forest that indicates an intrinsic system sensitivity to water availability across rainfall regimes, regardless of hydroclimatic conditions. We found higher WUE(e) in drier years that increased significantly with drought to a maximum WUE(e) across all biomes; and a minimum native state in wetter years that was common across hydroclimatic periods. This indicates biome-scale resilience to the interannual variability associated with the early twenty-first century drought--that is, the capacity to tolerate low, annual precipitation and to respond to subsequent periods of favourable water balance. These findings provide a conceptual model of ecosystem properties at the decadal scale applicable to the widespread altered hydroclimatic conditions that are predicted for later this century. Understanding the hydroclimatic threshold that will break down ecosystem resilience and alter maximum WUE(e) may allow us to predict land-surface consequences as large regions become more arid, starting with water-limited, low-productivity grasslands.

Correction to: Laser-assisted surgery of the upper aero-digestive tract: a clarification of nomenclature. A consensus statement of the European Laryngological Society.

The article 'Laser-assisted surgery of the upper aero-digestive tract: a clarification of nomenclature. A consensus statement of the European Laryngological Society,' written by Marc Remacle, Christoph Arens, Mostafa Badr Eldin, Guillermo Campos, Carlos Chiesa Estomba, Pavel Dulguerov, Ivana Fiz, Anastasios Hantzakos, Jerôme Keghian, Francesco Mora, Nayla Matar, Giorgio Peretti, Cesare Piazza, Gregory N. Postma, Vyas Prasad, Elisabeth Sjogren, Frederik G. Dikkers, was originally published Online First without open access. After publication in volume 274 issue 10, page 3723-3727 the authors decided to opt for Open Choice and to make the article an open access publication. Therefore, the copyright of the article has been changed to

Comment on 'Discovering hospital admission patterns using models learnt from electronic hospital records'. The importance of using the right codes.

CONTACT: guillermo.lopez@unimelb.edu.au.

CO2 exchange and evapotranspiration across dryland ecosystems of southwestern North America.

Global-scale studies suggest that dryland ecosystems dominate an increasing trend in the magnitude and interannual variability of the land CO2 sink. However, such analyses are poorly constrained by measured CO2 exchange in drylands. Here we address this observation gap with eddy covariance data from 25 sites in the water-limited Southwest region of North America with observed ranges in annual precipitation of 100-1000 mm, annual temperatures of 2-25°C, and records of 3-10 years (150 site-years in total). Annual fluxes were integrated using site-specific ecohydrologic years to group precipitation with resulting ecosystem exchanges. We found a wide range of carbon sink/source function, with mean annual net ecosystem production (NEP) varying from -350 to +330 gCm-2 across sites with diverse vegetation types, contrasting with the more constant sink typically measured in mesic ecosystems. In this region, only forest-dominated sites were consistent carbon sinks. Interannual variability of NEP, gross ecosystem production (GEP), and ecosystem respiration (Reco ) was larger than for mesic regions, and half the sites switched between functioning as C sinks/C sources in wet/dry years. The sites demonstrated coherent responses of GEP and NEP to anomalies in annual evapotranspiration (ET), used here as a proxy for annually available water after hydrologic losses. Notably, GEP and Reco were negatively related to temperature, both interannually within site and spatially across sites, in contrast to positive temperature effects commonly reported for mesic ecosystems. Models based on MODIS satellite observations matched the cross-site spatial pattern in mean annual GEP but consistently underestimated mean annual ET by ~50%. Importantly, the MODIS-based models captured only 20-30% of interannual variation magnitude. These results suggest the contribution of this dryland region to variability of regional to global CO2 exchange may be up to 3-5 times larger than current estimates.

Global and time-resolved monitoring of crop photosynthesis with chlorophyll fluorescence.

Photosynthesis is the process by which plants harvest sunlight to produce sugars from carbon dioxide and water. It is the primary source of energy for all life on Earth; hence it is important to understand how this process responds to climate change and human impact. However, model-based estimates of gross primary production (GPP, output from photosynthesis) are highly uncertain, in particular over heavily managed agricultural areas. Recent advances in spectroscopy enable the space-based monitoring of sun-induced chlorophyll fluorescence (SIF) from terrestrial plants. Here we demonstrate that spaceborne SIF retrievals provide a direct measure of the GPP of cropland and grassland ecosystems. Such a strong link with crop photosynthesis is not evident for traditional remotely sensed vegetation indices, nor for more complex carbon cycle models. We use SIF observations to provide a global perspective on agricultural productivity. Our SIF-based crop GPP estimates are 50-75% higher than results from state-of-the-art carbon cycle models over, for example, the US Corn Belt and the Indo-Gangetic Plain, implying that current models severely underestimate the role of management. Our results indicate that SIF data can help us improve our global models for more accurate projections of agricultural productivity and climate impact on crop yields. Extension of our approach to other ecosystems, along with increased observational capabilities for SIF in the near future, holds the prospect of reducing uncertainties in the modeling of the current and future carbon cycle.

Laser-assisted surgery of the upper aero-digestive tract: a clarification of nomenclature. A consensus statement of the European Laryngological Society.

Acronyms and abbreviations are frequently used in otorhinolaryngology and other medical specialties. CO2 laser-assisted transoral surgery of the pharynx, the larynx and the upper airway is a family of commonly performed surgical procedures termed transoral laser microsurgery (TLM). The abbreviation TLM can be confusing because of alternative modes of delivery. Classification and definition of the different types of procedures, performed transorally or transnasally, are proposed by the Working Committee for Nomenclature of the European Laryngological Society, emphasizing the type of laser used and the way this laser is transmitted. What is usually called TLM, would more clearly be defined as CO2 laser transoral microsurgery or CO2 TOLMS or CO2 laser transoral surgery only (with a handpiece) would be defined as CO2 TOLS. KTP transnasal flexible laser surgery would be KTP TNFLS. Transoral use of the flexible CO2 wave-guide with a handpiece would be a CO2 TOFLS. One can argue that these clarifications are not necessary and that the abbreviation TLM for transoral laser microsurgery is more than sufficient. But this is not the case. Laser surgery, office-based laser surgery and microsurgery are frequently and erroneously interchanged for one another. These classifications allow for a clear understanding of what was performed and what the results meant.

Patient-reported outcomes and therapeutic affordances of social media: findings from a global online survey of people with chronic pain.

BACKGROUND: Patient-reported outcomes (PROs) from social media use in chronic disease management continue to emerge. While many published articles suggest the potential for social media is positive, there is a lack of robust examination into mediating mechanisms that might help explain social media's therapeutic value. This study presents findings from a global online survey of people with chronic pain (PWCP) to better understand how they use social media as part of self-management. OBJECTIVE: Our aim is to improve understanding of the various health outcomes reported by PWCP by paying close attention to therapeutic affordances of social media. We wish to examine if demographics of participants underpin health outcomes and whether the concept of therapeutic affordances explains links between social media use and PROs. The goal is for this to help tailor future recommendations for use of social media to meet individuals' health needs and improve clinical practice of social media use. METHODS: A total of 231 PWCP took part in a global online survey investigating PROs from social media use. Recruited through various chronic disease entities and social networks, participants provided information on demographics, health/pain status, social media use, therapeutic affordances, and PROs from use. Quantitative analysis was performed on the data using descriptive statistics, cross-tabulation, and cluster analysis. RESULTS: The total dataset represented 218 completed surveys. The majority of participants were university educated (67.0%, 146/218) and female (83.9%, 183/218). More than half (58.7%, 128/218) were married/partnered and not working for pay (75.9%, 88/116 of these due to ill health). Fibromyalgia (46.6%, 55/118) and arthritis (27.1%, 32/118) were the most commonly reported conditions causing pain. Participants showed a clear affinity for social network site use (90.0%, 189/210), followed by discussion forums and blogs. PROs were consistent, suggesting that social media positively impact psychological, social, and cognitive health. Analysis also highlighted two strong correlations linking platform used and health outcomes (particularly psychological, social, and cognitive) to (1) the narrative affordance of social media and (2) frequency of use of the platforms. CONCLUSIONS: Results did not uncover definitive demographics or characteristics of PWCP for which health outcomes are impacted. However, findings corroborate literature within this domain suggesting that there is a typical profile of people who use social media for health and that social media are more suited to particular health outcomes. Exploration of the relationship between social media's therapeutic affordances and health outcomes, in particular the narration affordance, warrants further attention by patients and clinicians.

The presence of HIV-1 Tat protein second exon delays fas protein-mediated apoptosis in CD4+ T lymphocytes: a potential mechanism for persistent viral production.

HIV-1 replication is efficiently controlled by the regulator protein Tat (101 amino acids) and codified by two exons, although the first exon (1-72 amino acids) is sufficient for this process. Tat can be released to the extracellular medium, acting as a soluble pro-apoptotic factor in neighboring cells. However, HIV-1-infected CD4(+) T lymphocytes show a higher resistance to apoptosis. We observed that the intracellular expression of Tat delayed FasL-mediated apoptosis in both peripheral blood lymphocytes and Jurkat cells, as it is an essential pathway to control T cell homeostasis during immune activation. Jurkat-Tat cells showed impairment in the activation of caspase-8, deficient release of mitochondrial cytochrome c, and delayed activation of both caspase-9 and -3. This protection was due to a profound deregulation of proteins that stabilized the mitochondrial membrane integrity, such as heat shock proteins, prohibitin, or nucleophosmin, as well as to the up-regulation of NF-κB-dependent anti-apoptotic proteins, such as BCL2, c-FLIPS, XIAP, and C-IAP2. These effects were observed in Jurkat expressing full-length Tat (Jurkat-Tat101) but not in Jurkat expressing the first exon of Tat (Jurkat-Tat72), proving that the second exon, and particularly the NF-κB-related motif ESKKKVE, was necessary for Tat-mediated protection against FasL apoptosis. Accordingly, the protection exerted by Tat was independent of its function as a regulator of both viral transcription and elongation. Moreover, these data proved that HIV-1 could have developed strategies to delay FasL-mediated apoptosis in infected CD4(+) T lymphocytes through the expression of Tat, thus favoring the persistent replication of HIV-1 in infected T cells.

Functional response of U.S. grasslands to the early 21st-century drought.

Grasslands across the United States play a key role in regional livelihood and national food security. Yet, it is still unclear how this important resource will respond to the prolonged warm droughts and more intense rainfall events predicted with climate change. The early 21st-century drought in the southwestern United States resulted in hydroclimatic conditions that are similar to those expected with future climate change. We investigated the impact of the early 21st-century drought on aboveground net primary production (ANPP) of six desert and plains grasslands dominated by C4 (warm season) grasses in terms of significant deviations between observed and expected ANPP. In desert grasslands, drought-induced grass mortality led to shifts in the functional response to annual total precipitation (P(T)), and in some cases, new species assemblages occurred that included invasive species. In contrast, the ANPP in plains grasslands exhibited a strong linear function of the current-year P(T) and the previous-year ANPP, despite prolonged warm drought. We used these results to disentangle the impacts of interannual total precipitation, intra-annual precipitation patterns, and grassland abundance on ANPP, and thus generalize the functional response of C4 grasslands to predicted climate change. This will allow managers to plan for predictable shifts in resources associated with climate change related to fire risk, loss of forage, and ecosystem services.