Supplemental structured surveys and pre-existing detection models improve fine-scale density and population estimation with opportunistic community science data.

Density and population estimates aid in conservation and stakeholder communication. While free and broadly available community science data can effectively inform species distribution models, they often lack the information necessary to estimate imperfect detection and area sampled, thus limiting their use in fine-scale density modeling. We used structured distance-sampling surveys to model detection probability and calculate survey-specific detection offsets in community science models. We estimated density and population for 16 songbird species under three frameworks: (1) a fixed framework that assumes perfect detection within a specified survey radius, (2) an independent framework that calculates offsets from an independent source, and (3) a calibration framework that calculates offsets from supplemental surveys. Within the calibration framework, we examined the effects of calibration dataset size and data pooling. Estimates of density and population size were consistently biased low in the fixed framework. The independent and calibration frameworks produced reliable estimates for some species, but biased estimates for others, indicating discrepancies in detection probability between structured and community science surveys. The calibration framework produced reliable population estimates with as few as 10 calibration surveys with positive detections. Data pooling dramatically decreased bias. This study provides conservationists and managers with a cost-effective method of estimating density and population.

Integrated distance sampling models for simple point counts.

Point counts (PCs) are widely used in biodiversity surveys but, despite numerous advantages, simple PCs suffer from several problems: detectability, and therefore abundance, is unknown; systematic spatiotemporal variation in detectability yields biased inferences, and unknown survey area prevents formal density estimation and scaling-up to the landscape level. We introduce integrated distance sampling (IDS) models that combine distance sampling (DS) with simple PC or detection/nondetection (DND) data to capitalize on the strengths and mitigate the weaknesses of each data type. Key to IDS models is the view of simple PC and DND data as aggregations of latent DS surveys that observe the same underlying density process. This enables the estimation of separate detection functions, along with distinct covariate effects, for all data types. Additional information from repeat or time-removal surveys, or variable survey duration, enables the separate estimation of the availability and perceptibility components of detectability with DS and PC data. IDS models reconcile spatial and temporal mismatches among data sets and solve the above-mentioned problems of simple PC and DND data. To fit IDS models, we provide JAGS code and the new "IDS()" function in the R package unmarked. Extant citizen-science data generally lack the information necessary to adjust for detection biases, but IDS models address this shortcoming, thus greatly extending the utility and reach of these data. In addition, they enable formal density estimation in hybrid designs, which efficiently combine DS with distance-free, point-based PC or DND surveys. We believe that IDS models have considerable scope in ecology, management, and monitoring.

Reducing suicidal ideation in African American adolescents: A randomized controlled clinical trial.

OBJECTIVE: Suicide rates among African American adolescents have increased exponentially in recent years. The socioecological stressors that can increase suicide risk for African American adolescents, in conjunction with unique suicide risk manifestations within this group, require culturally sensitive preventive interventions. This study examines the efficacy of the Adapted-Coping With Stress course (A-CWS), a culturally tailored preventive intervention, to reduce suicidal ideation in African American adolescents, utilizing a randomized controlled design. METHOD: Participants included 410 ninth-grade students in a large Midwestern city; most students identified as Black/African American. Participants were randomly assigned to either the A-CWS intervention or standard care control condition. All participants were assessed at baseline, immediately postintervention, and 6 and 12 months postintervention. RESULTS: Treatment effects were examined using latent growth models comparing suicidal ideation trajectories in control and intervention conditions. Analyses were conducted using both intention-to-treat and treatment-as-received samples (i.e., intervention condition participants who attended at least 80% of sessions). In both intention-to-treat and treatment-as-received analyses, there was a significant treatment effect: Individuals in the A-CWS intervention condition with higher baseline ideation evidenced a superior reduction in suicidal ideation over the course of the study, relative to their counterparts in the standard care control condition. CONCLUSION: Findings indicate that the A-CWS preventive intervention is efficacious in reducing suicidal ideation among African American adolescents with higher levels of baseline suicidal ideation and that effects sustain over time, with the strongest effect evidenced 12 months postintervention. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Oyster aquaculture enhances sediment microbial diversity- Insights from a multi-omics study.

The global aquaculture industry has grown substantially, with consequences for coastal ecology and biogeochemistry. Oyster aquaculture can alter the availability of resources for microbes that live in sediments as oysters move large quantities of organic material to the sediments via filter feeding, possibly leading to changes in the structure and function of sediment microbial communities. Here, we use a chronosequence approach to investigate the impacts of oyster farming on sediment microbial communities over 7 years of aquaculture activity in a temperate coastal system. We detected shifts in bacterial composition (16S rRNA amplicon sequencing), changes in gene expression (meta-transcriptomics), and variations in sediment elemental concentrations (sediment geochemistry) across different durations of oyster farming. Our results indicate that both the structure and function of bacterial communities vary between control (no oysters) and farm sites, with an overall increase in diversity and a shift towards anoxic tolerance in farm sites. However, little to no variation was observed in either structure or function with respect to farming duration suggesting these sediment microbial communities are resilient to change. We also did not find any significant impact of farming on heavy metal accumulation in the sediments. The minimal influence of long-term oyster farming on sediment bacterial function and biogeochemical processes as observed here can bear important consequences for establishing best practices for sustainable farming in these areas. Importance: Sediment microbial communities drive a range of important ecosystem processes such as nutrient recycling and filtration. Oysters are well-known ecological engineers, and their presence is increasing as aquaculture expands in coastal waters globally. Determining how oyster aquaculture impacts sediment microbial processes is key to understanding current and future estuarine biogeochemical processes. Here, we use a multi-omics approach to study the effect of different durations of oyster farming on the structure and function of bacteria and elemental accumulation in the farm sediments. Our results indicate an increase in the diversity of bacterial communities in the farm sites with no such increases observed for elemental concentrations. Further, these effects persist across multiple years of farming with an increase of anoxic tolerant bacteria at farm sites. The multi-omics approach used in this study can serve as a valuable tool to facilitate understanding of the environmental impacts of oyster aquaculture.

Cognitive development from infancy to young adulthood in common marmosets (Callithrix jacchus): Effect of age, sex, and hormones on learning and affective state.

Studies looking at individual variability in cognition have increased in recent years. We followed 43 marmosets (21 males, 22 females) from infancy to young adulthood. At 3-months old, marmosets were trained to touch a rewarded stimulus. At 9-, 15-, and 21-months old, they were given visual discrimination and cognitive bias tests, and urine samples were collected to examine hormone levels. Marmosets were significantly more successful learners at 15 months than 9 months. Individuals who were more successful learners at 9 months were also more successful at 15 months, with more male learners than expected at 15 months. At 9 months, learning success was associated with higher cortisol levels. At 15 months, males with higher estradiol levels were more successful learners, whereas at 21 months, females with higher estradiol and cortisol levels tended to be less successful learners and more pessimistic. Nine months, therefore, appears to be an important developmental timepoint for acquiring cognitive control, which has developed by 15 months. Steroids may have differential effects on each sex, with complex interactions between gonadal and adrenal hormones having an influence on cognitive function over the lifespan. This longitudinal study offers new insight into cognition, including its development and biological underpinnings.

The application of epiphenotyping approaches to DNA methylation array studies of the human placenta.

BACKGROUND: Genome-wide DNA methylation (DNAme) profiling of the placenta with Illumina Infinium Methylation bead arrays is often used to explore the connections between in utero exposures, placental pathology, and fetal development. However, many technical and biological factors can lead to signals of DNAme variation between samples and between cohorts, and understanding and accounting for these factors is essential to ensure meaningful and replicable data analysis. Recently, "epiphenotyping" approaches have been developed whereby DNAme data can be used to impute information about phenotypic variables such as gestational age, sex, cell composition, and ancestry. These epiphenotypes offer avenues to compare phenotypic data across cohorts, and to understand how phenotypic variables relate to DNAme variability. However, the relationships between placental epiphenotyping variables and other technical and biological variables, and their application to downstream epigenome analyses, have not been well studied. RESULTS: Using DNAme data from 204 placentas across three cohorts, we applied the PlaNET R package to estimate epiphenotypes gestational age, ancestry, and cell composition in these samples. PlaNET ancestry estimates were highly correlated with independent polymorphic ancestry-informative markers, and epigenetic gestational age, on average, was estimated within 4 days of reported gestational age, underscoring the accuracy of these tools. Cell composition estimates varied both within and between cohorts, as well as over very long placental processing times. Interestingly, the ratio of cytotrophoblast to syncytiotrophoblast proportion decreased with increasing gestational age, and differed slightly by both maternal ethnicity (lower in white vs. non-white) and genetic ancestry (lower in higher probability European ancestry). The cohort of origin and cytotrophoblast proportion were the largest drivers of DNAme variation in this dataset, based on their associations with the first principal component. CONCLUSIONS: This work confirms that cohort, array (technical) batch, cell type proportion, self-reported ethnicity, genetic ancestry, and biological sex are important variables to consider in any analyses of Illumina DNAme data. We further demonstrate the specific utility of epiphenotyping tools developed for use with placental DNAme data, and show that these variables (i) provide an independent check of clinically obtained data and (ii) provide a robust approach to compare variables across different datasets. Finally, we present a general framework for the processing and analysis of placental DNAme data, integrating the epiphenotype variables discussed here.

Salt marsh nitrogen cycling: where land meets sea.

Salt marshes sit at the terrestrial-aquatic interface of oceans around the world. Unique features of salt marshes that differentiate them from their upland or offshore counterparts include high rates of primary production from vascular plants and saturated saline soils that lead to sharp redox gradients and a diversity of electron acceptors and donors. Moreover, the dynamic nature of root oxygen loss and tidal forcing leads to unique biogeochemical conditions that promote nitrogen cycling. Here, we highlight recent advances in our understanding of key nitrogen cycling processes in salt marshes and discuss areas where additional research is needed to better predict how salt marsh N cycling will respond to future environmental change.

eoPred: predicting the placental phenotype of early-onset preeclampsia using public DNA methylation data.

Background: A growing body of literature has reported molecular and histological changes in the human placenta in association with preeclampsia (PE). Placental DNA methylation (DNAme) and transcriptomic patterns have revealed molecular subgroups of PE that are associated with placental histopathology and clinical phenotypes of the disease. However, the clinical and molecular heterogeneity of PE both across and within subtypes complicates the study of this disease. PE is most strongly associated with placental pathology and adverse fetal and maternal outcomes when it develops early in pregnancy. We focused on placentae from pregnancies affected by preeclampsia that were delivered before 34 weeks of gestation to develop eoPred, a predictor of the DNAme signature associated with the placental phenotype of early-onset preeclampsia (EOPE). Results: Public data from 83 placental samples (HM450K), consisting of 42 EOPE and 41 normotensive preterm birth (nPTB) cases, was used to develop eoPred-a supervised model that relies on a highly discriminative 45 CpG DNAme signature of EOPE in the placenta. The performance of eoPred was assessed using cross-validation (AUC = 0.95) and tested in an independent validation cohort (n = 49, AUC = 0.725). A subset of fetal growth restriction (FGR) and late-PE cases showed a similar DNAme profile at the 45 predictive CpGs, consistent with the overlap in placental pathology between these conditions. The relationship between the EOPE probability generated by eoPred and various phenotypic variables was also assessed, revealing that it is associated with gestational age, and it is not driven by cell composition differences. Conclusion: eoPred relies on a 45-CpG DNAme signature to predict a homogeneous placental phenotype of EOPE in a discrete or continuous manner. Using this classifier should 1) aid in the study of placental insufficiency and improve the consistency of future placental DNAme studies of PE, 2) facilitate identifying the placental phenotype of EOPE in public data sets and 3) importantly, standardize the placental diagnosis of EOPE to allow better cross-cohort comparisons. Lastly, classification of cases with eoPred will be useful for investigating the relationship between placental pathology and genetic or environmental variables.

Psychopharmacology attitudes, beliefs, and practices among systemic family therapists and supervisors.

Many aspects of systemic family therapist (SFT) training and competence play a vital role in effective treatment and professional satisfaction. One area that has been significantly overlooked by many SFTs is the role of psychotropic medication (PM) in conjunction with talk therapy for optimal mental health outcomes. This study explores the current status of PM in SFT training and clinical practice. Our findings highlight the continued struggle of SFTs in their comfort level with addressing the PM needs of their clients. We identified a perceived inadequacy of SFT training and supervision regarding PM use. SFTs around the world need to find educational opportunities to improve their competence in working with their clients and their prescribed medications. Additional studies need to be conducted on strategies and mechanisms to improve client care. If SFTs are ignorant of PM, their treatment of clients-who often use PM-will be compromised.

Longitudinal patterns and predictors of suicidal ideation in African American adolescents.

Suicide rates among African American adolescents have increased dramatically. Suicidal ideation is associated with both suicide attempts and completions, thus understanding ideation patterns and predictors in African American adolescents is critical to informing prevention efforts. This study recruited 160 African American ninth grade students. Participants were those students randomized to the control condition of a randomized controlled preventive intervention. Of the 160 participants, 99 completed all assessment points and were included in latent transition analyses. We assessed participants four times: baseline then again at 6-, 12-, and 18-month postbaseline. Constructs of interest for this study included suicidal ideation, depression, hopelessness, and community violence exposure. A 2-class model (i.e., low ideation [LI] and high ideation [HI]) characterized ideation at each time point. A total of 86%-90% of participants were in the LI class in any given time point and 27.3% of participants were in the HI class at least once. Participants in the LI class tended to stay in that class, whereas those in the HI class often transitioned to the LI group. Depression and hopelessness, but not exposure to community violence, predicted HI class membership. Findings suggest that (a) most African American adolescents may experience suicide ideation at some point in time, (b) a concerning proportion of African American adolescents may experience high ideation, (c) high ideation is often time-limited, and (d) depression and hopelessness predict high ideation.

Effects of nitrate and ammonium on assimilation of nitric oxide by Heterosigma akashiwo.

The harmful alga Heterosigma akashiwo possesses a hybrid nitrate reductase (NR) enzyme, NR2-2/2HbN, which has the potential to convert NO to nitrate for assimilation into biomass. In previous research, NR transcription in H. akashiwo was induced by nitrate while NR activity was inhibited by ammonium. Here, the capacity of H. akashiwo to use NO in the presence of nitrate and/or ammonium was investigated to understand the regulation of NO assimilation. Continuous cultures of H. akashiwo were acclimated to growth on nitrate, ammonium, or a mixture of both. Aliquots from these cultures were spiked with 15N-labeled NO. The expression of genes involved in nitrogen assimilation was evaluated, as well as nitrate reductase activity and assimilation of 15N-labeled nitrogen into algal biomass. Results showed that NO induced expression and activity of NR, and upregulated expression of GOGAT regardless of the presence of other inorganic nitrogen sources, while GS expression decreased over time. Furthermore, 15NO uptake and assimilation was significantly higher in cultures acclimated for growth on ammonium compared to cultures acclimated for growth on nitrate alone. Assimilation of NO may provide H. akashiwo with a competitive advantage in N-poor environments or areas with elevated NO.

The Impact of COVID-19 and Telehealth Services on Attrition Rates in Psychotherapy.

Attrition in psychotherapy has been identified as a significant obstacle in the productive delivery of mental health services. Defined generally as the ending of a treatment prior to proper optimal benefit, attrition both hinders treatment efficacy and costeffectiveness in therapy. With the demands for quality mental health services increasing, resources must be identified to reduce barriers to such services. The COVID-19 pandemic has resulted in the emergence of one potential resources: telehealth services. The current study aims to identify how COVID-19 and telehealth services have influenced attrition by analyzing attrition rates from both before and during the pandemic in a community health center where a transition to telehealth was made at the start of the pandemic. In addition, the variables of age, gender, socioeconomic status, and insurance coverage were also tested as potential predictors of attrition. Using de-identified patient information, clients who had participated in therapy services within a six-month period at a community health center (N = 329) were selected. A survival analysis was used to assess the time taken from initial appointment to the point of attrition. Results indicated that those who attended therapy via telehealth were less likely to stop attending treatment than those who participated in therapy in person. Individuals who used both in-person and telehealth visits were the least likely to terminate treatment prematurely. Clinical implications include the need for therapists to offer both telehealth and in-person services in order to give clients more resources to reduce a large barrier to needed mental healthcare treatment. Supplementary Information: The online version contains supplementary material available at 10.1007/s10591-023-09661-0.

Social Support Coping for African American Adolescents: Effect of a Culturally Grounded Randomized Controlled Trial Intervention.

The effect of the Adapted-Coping with Stress (A-CWS) intervention on social support coping was examined, using a randomized controlled trial design. The participants were 410 ninth-grade students (ages 14 to 16 years and mostly African American) living in low-resourced neighborhoods. Participants were randomly assigned 1:1 to either the A-CWS intervention or a standard care control condition. All participants were assessed at their schools before implementation of the intervention, at intervention completion, and again at 6- and 12-month post-intervention. Engagement in social support coping was examined in both intention-to-treat and treatment-as-received samples (i.e., intervention participants who attended at least 12 A-CWS treatment sessions and participants in the standard care control condition), using latent growth models. In intention-to-treat analyses, no significant treatment effects were identified. In treatment-as-received analyses, results revealed a significant association between social support coping and treatment condition; levels of social support coping decreased over time in the control condition, but they remained relatively stable in the treatment condition. The results indicate adequate intervention adherence and efficacy of the A-CWS to sustain social support coping within a sample of youth at high risk for stress exposure and associated disorders.Clinical Trial Registration: clinicaltrials.gov identifier: NCT0395445.

Elevated inbreeding in Heliconia tortuosa is determined by tropical forest stand age, isolation and loss of hummingbird functional diversity.

Forest conversion and habitat loss are major threats to biological diversity. Forest regeneration can mitigate the negative effects of old-growth forest loss on species diversity, but less is known about the extent to which forest loss reduces genetic diversity in remnant populations and whether secondary forests play a role in the maintenance of genetic diversity. We quantified genetic diversity in a tropical hummingbird-pollinated understorey herb, Heliconia tortuosa, across a landscape mosaic of primary and secondary forest regrowth. Using microsatellite genotypes from >850 adult and juvenile plants within 33 forest patches and extensive bird surveys, we examined the effect of contemporary and historical landscape features including forest age (primary vs. secondary forest), stand isolation and pollinator assemblages on genetic diversity and levels of inbreeding in H. tortuosa. We found that inbreeding was up to three times higher in secondary forest, and this effect was amplified with reductions in primary forest in the surrounding landscape through reduced observed heterozygosity in isolated fragments. Inbreeding in forest patches was negatively correlated with the local frequency of specialist long-distance foraging traplining hummingbirds. Traplining hummingbirds therefore appear to facilitate mating among unrelated plants-an inference we tested using empirically parameterized simulations. Higher levels of inbreeding in H. tortuosa are therefore associated with reduced functional diversity of hummingbirds in secondary forests and forest patches isolated from primary forests. Our findings suggest a cryptic consequence of primary forest loss and secondary forest regeneration through the disruption of mutualistic interactions resulting in the erosion of genetic diversity in a common understorey plant.

Nitrogen fixation: a poorly understood process along the freshwater-marine continuum.

Although N2 fixation is a major component of the global N cycle and has been extensively studied in open-ocean and terrestrial ecosystems, rates and ecological dynamics remain virtually unknown for the inland and coastal aquatic ecosystems (lakes, wetlands, rivers, streams, estuaries) that connect terrestrial and marine biomes. This is due to the diversity of these habitats, as well as the traditional paradigm that N2 fixation rates were low to nonexistent, and therefore not important, in these ecosystems. We identify three major research themes to advance understanding of aquatic N2 fixation: 1) the biological diversity of diazotrophs and variability of N2 fixation rates, 2) the ecological stoichiometry of N2 fixation, and 3) the upscaling of N2 fixation rates from genes to ecosystems. Coordinating research across these areas will advance limnology and oceanography by fully integrating N2 fixation into ecological dynamics of aquatic ecosystems from local to global scales.

Cold Seeps on the Passive Northern U.S. Atlantic Margin Host Globally Representative Members of the Seep Microbiome with Locally Dominant Strains of Archaea.

Marine cold seeps are natural sites of methane emission and harbor distinct microbial communities capable of oxidizing methane. The majority of known cold seeps are on tectonically active continental margins, but recent discoveries have revealed abundant seeps on passive margins as well, including on the U.S. Atlantic Margin (USAM). We sampled in and around four USAM seeps and combined pore water geochemistry measurements with amplicon sequencing of 16S rRNA and mcrA (DNA and RNA) to investigate the microbial communities present, their assembly processes, and how they compare to communities at previously studied sites. We found that the USAM seeps contained communities consistent with the canonical seep microbiome at the class and order levels but differed markedly at the sequence variant level, especially within the anaerobic methanotrophic (ANME) archaea. The ANME populations were highly uneven, with just a few dominant mcrA sequence variants at each seep. Interestingly, the USAM seeps did not form a distinct phylogenetic cluster when compared with other previously described seeps around the world. Consistent with this, we found only a very weak (though statistically significant) distance-decay trend in seep community similarity across a global data set. Ecological assembly indices suggest that the USAM seep communities were assembled primarily deterministically, in contrast to the surrounding nonseep sediments, where stochastic processes dominated. Together, our results suggest that the primary driver of seep microbial community composition is local geochemistry-specifically methane, sulfide, nitrate, acetate, and ammonium concentrations-rather than the geologic context, the composition of nearby seeps, or random events of dispersal. IMPORTANCE Cold seeps are now known to be widespread features of passive continental margins, including the northern U.S. Atlantic Margin (USAM). Methane seepage is expected to intensify at these relatively shallow seeps as bottom waters warm and underlying methane hydrates dissociate. While methanotrophic microbial communities might reduce or prevent methane release, microbial communities on passive margins have rarely been characterized. In this study, we investigated the Bacteria and Archaea at four cold seeps on the northern USAM and found that despite being colocated on the same continental slope, the communities significantly differ by site at the sequence variant level, particularly methane-cycling community members. Differentiation by site was not observed in similarly spaced background sediments, raising interesting questions about the dispersal pathways of cold seep microorganisms. Understanding the genetic makeup of these discrete seafloor ecosystems and how their microbial communities develop will be increasingly important as the climate changes.

Receiving Medical Care for Chronic Migraines: A Phenomenological Study.

OBJECTIVES: Treating chronic migraine (CM) effectively is one of the greatest challenges a primary care provider (PCP) may encounter. Many patients with CM report dissatisfaction and minimal gains from treatment, despite using the best medical interventions available. For this study, patients with CM and their partners provided insight into how PCPs could improve CM treatment. METHODS: Using the immersion/crystallization phenomenological method, we collected data from 11 patients with CM and 8 of their partners (N = 19). We analyzed open-ended survey responses about migraine treatment from patients with CM, as well as transcripts from interviews with patients with CM and their partners (14 interviews total) about their medical experiences. RESULTS: Participants used a variety of pharmacological and alternative treatments in search of a cure; wanted to be treated more collaboratively; and repeatedly gave up on medical care, but then sought treatment again. CONCLUSIONS: PCPs could be trained to encourage patients with CM to shift toward accepting and managing migraines rather than endlessly hoping for a cure. Patients could be taught to manage CM using a holistic, biopsychosocial approach.

Motivational increase of androgens and behavior by infant distress calls in highly responsive common marmoset fathers, Callithrix jacchus.

Common marmoset fathers are highly involved in care of their infants. However, variability exists in their response to infant behavior even in paternally experienced fathers. Using infant distress cries as a motivation test, we investigated: 1. the differences in paternally experienced fathers' motivation to search for the infant vocalization stimuli; 2. the relationship between a father's motivation to search for the source of the infant cries and testosterone levels; and 3. if there is a rapid steroidogenesis pathway leading to increased testosterone and estradiol in the peripheral circulation. Only 44% of the paternally experienced fathers showed a high frequency of searching for the source of the infant distress cries. Through the use of multisteroid analysis, we found high responsive fathers had significantly higher levels of progesterone and testosterone in response to infant distress cries compared to a control stimulus with progesterone and androstenedione correlating with testosterone, while no differences were seen in low responders. The frequency to search for the infant stimuli was positively correlated with higher testosterone compared to control vocal levels. These results suggest that searching for the source of infant cries represents a motivation behavior for fathers that is activated by testosterone and reflects rapid circulating testosterone.

Evidence, causes, and consequences of declining nitrogen availability in terrestrial ecosystems.

The productivity of ecosystems and their capacity to support life depends on access to reactive nitrogen (N). Over the past century, humans have more than doubled the global supply of reactive N through industrial and agricultural activities. However, long-term records demonstrate that N availability is declining in many regions of the world. Reactive N inputs are not evenly distributed, and global changes-including elevated atmospheric carbon dioxide (CO2) levels and rising temperatures-are affecting ecosystem N supply relative to demand. Declining N availability is constraining primary productivity, contributing to lower leaf N concentrations, and reducing the quality of herbivore diets in many ecosystems. We outline the current state of knowledge about declining N availability and propose actions aimed at characterizing and responding to this emerging challenge.