RESUMO
Fungi are among the most diverse and ecologically important kingdoms in life. However, the distributional ranges of fungi remain largely unknown as do the ecological mechanisms that shape their distributions1,2. To provide an integrated view of the spatial and seasonal dynamics of fungi, we implemented a globally distributed standardized aerial sampling of fungal spores3. The vast majority of operational taxonomic units were detected within only one climatic zone, and the spatiotemporal patterns of species richness and community composition were mostly explained by annual mean air temperature. Tropical regions hosted the highest fungal diversity except for lichenized, ericoid mycorrhizal and ectomycorrhizal fungi, which reached their peak diversity in temperate regions. The sensitivity in climatic responses was associated with phylogenetic relatedness, suggesting that large-scale distributions of some fungal groups are partially constrained by their ancestral niche. There was a strong phylogenetic signal in seasonal sensitivity, suggesting that some groups of fungi have retained their ancestral trait of sporulating for only a short period. Overall, our results show that the hyperdiverse kingdom of fungi follows globally highly predictable spatial and temporal dynamics, with seasonality in both species richness and community composition increasing with latitude. Our study reports patterns resembling those described for other major groups of organisms, thus making a major contribution to the long-standing debate on whether organisms with a microbial lifestyle follow the global biodiversity paradigms known for macroorganisms4,5.
Assuntos
Microbiologia do Ar , Biodiversidade , DNA Fúngico , Fungos , Estações do Ano , Análise Espaço-Temporal , DNA Fúngico/análise , DNA Fúngico/genética , Fungos/genética , Fungos/classificação , Fungos/isolamento & purificação , Micorrizas/genética , Micorrizas/classificação , Micorrizas/isolamento & purificação , Filogenia , Esporos Fúngicos/classificação , Esporos Fúngicos/isolamento & purificação , Temperatura , Clima Tropical , Mapeamento GeográficoRESUMO
Numerous studies have shown reduced performance in plants that are surrounded by neighbours of the same species1,2, a phenomenon known as conspecific negative density dependence (CNDD)3. A long-held ecological hypothesis posits that CNDD is more pronounced in tropical than in temperate forests4,5, which increases community stabilization, species coexistence and the diversity of local tree species6,7. Previous analyses supporting such a latitudinal gradient in CNDD8,9 have suffered from methodological limitations related to the use of static data10-12. Here we present a comprehensive assessment of latitudinal CNDD patterns using dynamic mortality data to estimate species-site-specific CNDD across 23 sites. Averaged across species, we found that stabilizing CNDD was present at all except one site, but that average stabilizing CNDD was not stronger toward the tropics. However, in tropical tree communities, rare and intermediate abundant species experienced stronger stabilizing CNDD than did common species. This pattern was absent in temperate forests, which suggests that CNDD influences species abundances more strongly in tropical forests than it does in temperate ones13. We also found that interspecific variation in CNDD, which might attenuate its stabilizing effect on species diversity14,15, was high but not significantly different across latitudes. Although the consequences of these patterns for latitudinal diversity gradients are difficult to evaluate, we speculate that a more effective regulation of population abundances could translate into greater stabilization of tropical tree communities and thus contribute to the high local diversity of tropical forests.
Assuntos
Biodiversidade , Florestas , Mapeamento Geográfico , Árvores , Modelos Biológicos , Especificidade da Espécie , Árvores/classificação , Árvores/fisiologia , Clima TropicalRESUMO
Tree fecundity and recruitment have not yet been quantified at scales needed to anticipate biogeographic shifts in response to climate change. By separating their responses, this study shows coherence across species and communities, offering the strongest support to date that migration is in progress with regional limitations on rates. The southeastern continent emerges as a fecundity hotspot, but it is situated south of population centers where high seed production could contribute to poleward population spread. By contrast, seedling success is highest in the West and North, serving to partially offset limited seed production near poleward frontiers. The evidence of fecundity and recruitment control on tree migration can inform conservation planning for the expected long-term disequilibrium between climate and forest distribution.
Assuntos
Mudança Climática , Árvores/fisiologia , Ecossistema , Fertilidade/fisiologia , Geografia , América do Norte , IncertezaRESUMO
Despite its importance for forest regeneration, food webs, and human economies, changes in tree fecundity with tree size and age remain largely unknown. The allometric increase with tree diameter assumed in ecological models would substantially overestimate seed contributions from large trees if fecundity eventually declines with size. Current estimates are dominated by overrepresentation of small trees in regression models. We combined global fecundity data, including a substantial representation of large trees. We compared size-fecundity relationships against traditional allometric scaling with diameter and two models based on crown architecture. All allometric models fail to describe the declining rate of increase in fecundity with diameter found for 80% of 597 species in our analysis. The strong evidence of declining fecundity, beyond what can be explained by crown architectural change, is consistent with physiological decline. A downward revision of projected fecundity of large trees can improve the next generation of forest dynamic models.
Assuntos
Fertilidade , Modelos Biológicos , Regeneração , Árvores/crescimento & desenvolvimento , FlorestasRESUMO
BACKGROUND: Educational programs to prepare nurse practitioners (NPs) were historically built upon foundational nursing experience. Originally prepared as certificate programs in 1965, the educational requirements for nurse practitioners (NPs) rapidly shifted from certificate programs to the Master's degree (DellaBella, 2015; Fairman, 2008). As Doctor of Nursing Practice (DNP) degree programs increase in number, it is unknown whether this foundational nursing experience has changed, or if it differs by certification type for pediatric nurse practitioners (PNPs). This study aimed to evaluate the educational preparation and prior nursing experience of primary care and acute care certified PNPs. METHODS: A national survey of members of the Pediatric Nurse Practitioner Certification Board (N = 17,530) was completed (Mudd et al., 2022). A sub-analysis of this data was conducted (n = 1974). RESULTS: There was no statistical evidence among either primary or acute care PNPs of an association between previous nursing experience and type of degree preparation (Master's or DNP). There was only a weak association between educational preparation and experience among acute care nurse practitioners. Most respondents were prepared at the Master's level, and 85% of all respondents had >1 year of nursing experience prior to returning for additional PNP education. DISCUSSION: This study adds to the literature as it describes the educational preparation and foundational nursing experience of primary and acute care PNPs. It can serve as a benchmark as the move to the DNP continues for Advanced Practice Registered Nurse preparation.
Assuntos
Certificação , Educação de Pós-Graduação em Enfermagem , Humanos , Estados Unidos , Masculino , Feminino , Profissionais de Enfermagem Pediátrica/educação , Adulto , Profissionais de Enfermagem/educação , Competência Clínica , Inquéritos e Questionários , Pessoa de Meia-IdadeRESUMO
OBJECTIVES: We aimed to develop a standardized scoring tool to measure point-of-care ultrasound (POCUS) image quality and to determine validity evidence for its use to assess lung ultrasound image quality. METHODS: The POCUS Image Quality (POCUS IQ) scale was developed by POCUS-trained physicians to assess sonographers' image acquisition skills by evaluating image quality for any POCUS application. The scale was piloted using lung images of healthy standardized patients acquired by three expert sonographers compared to three novices before and after training. All images (experts, novices pre-training, novices post-training) were scored on the POCUS IQ scale by three blinded POCUS-trained physicians. Reliability was assessed with fully-crossed generalizability and decision studies. Validity was assessed using Messick's framework. RESULTS: Content validity was supported by the tool's development process of literature review, expert consensus, and pilot testing. Response process was supported by reviewer training and the blinded scoring process. Relation to other variables was supported by scores relating to sonographer experience: median expert score = 10.5/14 (IQR: 4), median novice pre-training score = 6/14 (IQR: 2.25), and novices' improvement after training (median post-training score = 12/14, IQR: 3.25). Internal structure was supported by internal consistency data (coefficient alpha = 0.84, omega coefficient = 0.91) and the generalizability study showing the main contributor to score variability was the sonographer (51%). The G-coefficient was 0.89, suggesting very good internal structure, however, Gwet's AC2 was 0.5, indicating moderate interrater reliability. The D study projected a minimum of 1 reviewer and 2 patients are needed for good psychometric reliability. CONCLUSIONS: The POCUS scale has good preliminary validity evidence as an assessment tool for lung POCUS image acquisition skills. Further studies are needed to demonstrate its utility for other POCUS applications and as a feedback tool for POCUS learners.
Assuntos
Médicos , Sistemas Automatizados de Assistência Junto ao Leito , Humanos , Reprodutibilidade dos Testes , Ultrassonografia/métodos , Testes ImediatosRESUMO
AIM: The purpose of this study was to explore student experiences within a health care disparity simulation, embedded in maternal-child content. BACKGROUND: Health care disparities related to race and ethnicity in the maternal-child population are daunting among African American and Hispanic women. METHOD: Participants completed the Simulation Effectiveness Tool-Modified, a rapid-fire huddle questionnaire, and a demographic instrument. All students participated in structured debriefing. RESULTS: Student responses ( n = 69) demonstrated effectiveness in learning via this scenario. CONCLUSION: The rapid-fire huddle and debriefing are important elements when health care disparities are introduced into nursing curricula.
Assuntos
Bacharelado em Enfermagem , Treinamento por Simulação , Estudantes de Enfermagem , Humanos , Feminino , Disparidades em Assistência à Saúde , Escolaridade , AprendizagemRESUMO
Lack of tree fecundity data across climatic gradients precludes the analysis of how seed supply contributes to global variation in forest regeneration and biotic interactions responsible for biodiversity. A global synthesis of raw seedproduction data shows a 250-fold increase in seed abundance from cold-dry to warm-wet climates, driven primarily by a 100-fold increase in seed production for a given tree size. The modest (threefold) increase in forest productivity across the same climate gradient cannot explain the magnitudes of these trends. The increase in seeds per tree can arise from adaptive evolution driven by intense species interactions or from the direct effects of a warm, moist climate on tree fecundity. Either way, the massive differences in seed supply ramify through food webs potentially explaining a disproportionate role for species interactions in the wet tropics.
Assuntos
Florestas , Árvores , Biodiversidade , Clima , Fertilidade , SementesRESUMO
OBJECTIVE: To gather and evaluate validity evidence in the form of content and reliability of scores produced by 2 surgical skills assessment instruments, 1) a checklist, and 2) a modified form of the Objective Structured Assessment of Technical Skills (OSATS) global rating scale (GRS). STUDY DESIGN: Prospective randomized blinded study. SAMPLE POPULATION: Veterinary surgical skills educators (n =10) evaluated content validity. Scores from students in their third preclinical year of veterinary school (n = 16) were used to assess reliability. METHODS: Content validity was assessed using Lawshe's method to calculate the Content Validity Index (CVI) for the checklist and modified OSATS GRS. The importance and relevance of each item was determined in relation to skills needed to successfully perform supervised surgical procedures. The reliability of scores produced by both instruments was determined using generalizability (G) theory. RESULTS: Based on the results of the content validation, 39 of 40 checklist items were included. The 39-item checklist CVI was 0.81. One of the 6 OSATS GRS items was included. The 1-item GRS CVI was 0.80. The G-coefficients for the 40-item checklist and 6-item GRS were 0.85 and 0.79, respectively. CONCLUSION: Content validity was very good for the 39-item checklist and good for the 1-item OSATS GRS. The reliability of scores from both instruments was acceptable for a moderate stakes examination. IMPACT: These results provide evidence to support the use of the checklist described and a modified 1-item OSAT GRS in moderate stakes examinations when evaluating preclinical third-year veterinary students' technical surgical skills on low-fidelity models.
Assuntos
Competência Clínica , Internato e Residência , Animais , Lista de Checagem , Humanos , Estudos Prospectivos , Reprodutibilidade dos Testes , EstudantesRESUMO
Pathogens play an important part in shaping the structure and dynamics of natural communities, because species are not affected by them equally. A shared goal of ecology and epidemiology is to predict when a species is most vulnerable to disease. A leading hypothesis asserts that the impact of disease should increase with host abundance, producing a 'rare-species advantage'. However, the impact of a pathogen may be decoupled from host abundance, because most pathogens infect more than one species, leading to pathogen spillover onto closely related species. Here we show that the phylogenetic and ecological structure of the surrounding community can be important predictors of disease pressure. We found that the amount of tissue lost to disease increased with the relative abundance of a species across a grassland plant community, and that this rare-species advantage had an additional phylogenetic component: disease pressure was stronger on species with many close relatives. We used a global model of pathogen sharing as a function of relatedness between hosts, which provided a robust predictor of relative disease pressure at the local scale. In our grassland, the total amount of disease was most accurately explained not by the abundance of the focal host alone, but by the abundance of all species in the community weighted by their phylogenetic distance to the host. Furthermore, the model strongly predicted observed disease pressure for 44 novel host species we introduced experimentally to our study site, providing evidence for a mechanism to explain why phylogenetically rare species are more likely to become invasive when introduced. Our results demonstrate how the phylogenetic and ecological structure of communities can have a key role in disease dynamics, with implications for the maintenance of biodiversity, biotic resistance against introduced weeds, and the success of managed plants in agriculture and forestry.
Assuntos
Biodiversidade , Pradaria , Filogenia , Doenças das Plantas/estatística & dados numéricos , Plantas/classificação , California , Bases de Dados Factuais , Espécies Introduzidas/tendências , Densidade DemográficaRESUMO
BACKGROUND: Healthcare simulation has expanded dramatically; however, little is known about the scope of simulation in acute care hospitals. METHODS: A descriptive, cross-sectional online survey was used. Participants included nurse executives from acute care hospitals in California. RESULTS: Most organizations (96%) used simulation primarily for education, 37% used simulation for health system integration and systems testing, 30% used it for error investigation, 15% used it for research, and 15% used it for patient/family education. CONCLUSIONS: Organizations have a substantial opportunity to increase the scope of simulation beyond education to include systems integration, clinical systems testing, and other translational simulation activities. This targeted focus on patient safety and quality will allow hospitals to improve financial performance and maximize scarce resources.
Assuntos
Eficiência Organizacional/normas , Manequins , Recursos Humanos de Enfermagem Hospitalar/educação , Equipe de Assistência ao Paciente/organização & administração , Simulação de Paciente , California , Competência Clínica , Simulação por Computador , Estudos Transversais , HumanosRESUMO
BACKGROUND: Opioid-induced respiratory depression (OIRD) is a serious adverse reaction associated with opioid administration. LOCAL PROBLEM: The purpose of this quality improvement study was to evaluate the impact of implementing a clinical practice guideline for OIRD in a medical-surgical setting lacking standardized monitoring techniques and reporting criteria for patients receiving opioid analgesia. METHODS: An American Society for Pain Management Nursing protocol was implemented in 4 medical/surgical units. The impact on OIRD-related nurse knowledge, documentation, and opioid-related rapid response calls was measured pre- and postimplementation. RESULTS: Nurse OIRD-related knowledge significantly increased. The number of naloxone administrations associated with prior intravenous opioid analgesic administration did not significantly change. However, there was a significant decrease in the postimplementation number of respiratory distress-related rapid response calls. CONCLUSIONS: Implementation of the American Society for Pain Management Nursing guidelines had a positive impact on knowledge, documentation, early intervention of OIRD, and the number of opioid-related rapid response calls.
Assuntos
Analgésicos Opioides/uso terapêutico , Guias como Assunto , Hipnóticos e Sedativos/uso terapêutico , Insuficiência Respiratória/etiologia , Analgésicos Opioides/efeitos adversos , Analgésicos Opioides/farmacologia , Avaliação Educacional/métodos , Humanos , Hipnóticos e Sedativos/farmacologia , Meio-Oeste dos Estados Unidos , Desenvolvimento de Programas/métodos , Insuficiência Respiratória/prevenção & controle , Fatores de RiscoRESUMO
BACKGROUND: Development of professional nursing values is critical within registered nurse-to-bachelor of science in nursing programs to prepare nurses for increasingly complex and diverse work environments. The results of previous studies have been inconsistent, with few studies focusing on online registered nurse-to-bachelor of science in nursing programs. In addition, little is known regarding the effectiveness of the educational methods used to support advancement of professional values and ethical practice. OBJECTIVE: The object of this study was to gain an understanding of nursing students' attitudes and beliefs about professional values at entry and exit of an online registered nurse-to-bachelor of science in nursing program that includes a standalone ethics course and integrates American Nurses Association Code of Ethics provisions throughout the curriculum. RESEARCH DESIGN: For this one-group pretest-posttest, quasi-experimental design, longitudinal matched-pair data were gathered at program entry and exit using the Nurses Professional Values Scale-Revised. PARTICIPANTS AND RESEARCH CONTEXT: In all, 119 students of an online registered nurse-to-bachelor of science in nursing program at a Midwest public university who completed entry and exit surveys between spring 2015 and spring 2018 were included in this study. ETHICAL CONSIDERATIONS: This study was reviewed and determined to be exempt by the university's institutional review board. FINDINGS: The results showed a significant increase in total posttest scores when considering all participants. However, students who took the ethics course after the pretest demonstrated a significant increase in posttest scores, while students who took the ethics course prior to the pretest demonstrated a small increase that was not statistically significant. Significant increases were also found in the professionalism, activism, and trust factors. DISCUSSION: This study supports previous study findings where students scored higher on caring and lower on activism and professionalism factors. The largest gains were made after completing the ethics course. CONCLUSION: The results suggest that requiring a standalone ethics course in the registered nurse-to-bachelor of science in nursing curriculum had a positive impact on self-reported professional values.
Assuntos
Profissionalismo/ética , Valores Sociais , Estudantes de Enfermagem/psicologia , Adulto , Atitude do Pessoal de Saúde , Estudos de Coortes , Currículo/tendências , Bacharelado em Enfermagem/métodos , Bacharelado em Enfermagem/tendências , Feminino , Humanos , Estudos Longitudinais , Masculino , Estudantes de Enfermagem/estatística & dados numéricosRESUMO
Reforestation is challenging when timber harvested areas have been degraded, invaded by nonnative species, or are of marginal suitability to begin with. Conifers form mutualistic partnerships with ectomycorrhizal fungi (EMF) to obtain greater access to soil resources, and these partnerships may be especially important in degraded areas. However, timber harvest can impact mycorrhizal fungi by removing or compacting topsoil, removing host plants, and warming and drying the soil. We used a field experiment to evaluate the role of EMF in Douglas-fir reforestation in clearcuts invaded by Cytisus scoparius (Scotch broom) where traditional reforestation approaches have repeatedly failed. We tested how planting distance from intact Douglas-fir forest edges influenced reforestation success and whether inoculation with forest soils can be used to restore EMF relationships. We used an Illumina DNA sequencing approach to measure the abundance, richness and composition of ectomycorrhizal fungi on Douglas-fir roots, and assessed differences in Douglas-fir seedling survival and growth near to and far from forest edges with and without forest soil inoculum. Planting Douglas-fir seedlings near forest edges increased seedling survival, growth, and EMF root colonization. Edge proximity had no effect on EMF richness but did change fungal community composition. Inoculations with forest soil did not increase EMF abundance or richness or change community composition, nor did it improve seedling establishment. With Illumina sequencing, we identified two to three times greater species richness than described in previous edge effects studies. Of the 95 EMF species we identified, 40% of the species occurred on less than 5% of the seedlings. The ability to detect fungi at low abundance may explain why we did not detect differences in EMF richness with distance to hosts as previous studies. Our findings suggest that forest edges are suitable for reforestation, even when the interiors of deforested areas are not. We advocate for timber harvest designs that maximize edge habitat where ectomycorrhizal fungi contribute to tree establishment. However, this study does not support the use of inoculation with forest soil as a simple method to enhance EMF and seedling survival.
Assuntos
Micorrizas , Pseudotsuga , Florestas , Raízes de Plantas , Plântula , Solo , Microbiologia do Solo , ÁrvoresRESUMO
BACKGROUND: Human morphology is a critical component of dental and medical graduate training. Innovations in basic science teaching methods are needed to keep up with an ever-changing landscape of technology. The purpose of this study was to investigate whether students in a medical and dental histology course would have better grades if they used gaming software Kahoot® and whether gamification effects on learning and enjoyment. METHODS: In an effort to both evoke students' interest and expand their skill retention, an online competition using Kahoot® was implemented for first-year students in 2018 (n = 215) at the University of Eastern Finland. Additionally, closed (160/215) or open-ended (41/215) feedback questions were collected and analyzed. RESULTS: The Kahoot® gamification program was successful and resulted in learning gains. The overall participant satisfaction using Kahoot® was high, with students (124/160) indicating that gamification increased their motivation to learn. The gaming approach seemed to enable the students to overcome individual difficulties (139/160) and to set up collaboration (107/160); furthermore, gamification promoted interest (109/160), and the respondents found the immediate feedback from senior professionals to be positive (146/160). In the open-ended survey, the students (23/41) viewed collaborative team- and gamification-based learning positively. CONCLUSION: This study lends support to the use of gamification in the teaching of histology and may provide a foundation for designing a gamification-integrated curriculum across healthcare disciplines.
Assuntos
Desempenho Acadêmico , Jogos Experimentais , Histologia/educação , Internet , Ensino , Currículo , Finlândia , Humanos , Estudantes de MedicinaRESUMO
AIM: The purpose of the study was to evaluate the psychometric properties of the Facilitator Competency Rubric (FCR). BACKGROUND: The FCR was developed to fill a deficit in tools available to holistically evaluate competency of simulation facilitators. METHOD: The FCR has five constructs: preparation, prebriefing, facilitation, debriefing, and evaluation. Benner's novice-to-expert theory was used to categorize subcomponents. Expert panel validation was sought. Participants from four baccalaureate nursing programs completed 107 observations of facilitators using the FCR. RESULTS: Interrater reliability as assessed using generalizability theory was good. G coefficients ranged from good to excellent (.80 to .99). FCR items appeared to be well constructed. Term, day of the week, time of day, and simulation type were significant predictors of the FCR global score. CONCLUSION: The FCR is a valid, reliable tool that can be used for formative or summative evaluation of simulation facilitators. Scores can guide and prioritize faculty development.
Assuntos
Competência Clínica , Educação em Enfermagem , Psicometria , Educação em Enfermagem/normas , Humanos , Reprodutibilidade dos TestesRESUMO
Gaining experience and dexterity for trans-rectal cattle palpation requires substantial training. Simulation allows students to perform palpation without risks and to obtain feedback, but many believe live cattle palpation is essential. Limited research exists on the proper training method for live animal trans-rectal palpation. This study compared student improvement in laboratory palpation skills when assigned to the same cows versus choosing a cow at random. The hypothesis for the study was that students assigned the same cow, as compared to students choosing a cow at random, would be more accurate at palpation, would learn what structures are present on the ovaries and what size the reproductive tract measures, and would be able to follow the cyclicity of the cow. Cervical diameter, uterine tone, diameter of left and right uterine horns, and ovarian structures were recorded over time. Responses were compared to laboratory instructors' responses and Z-tests for proportions were used to test the differences in percentage correct at each time point for each palpation exercise. Overall the experiment showed that assigning students to certain cows will not improve their trans-rectal palpation training. However, asking students to identify specific landmarks with quantitative measurements did allow for more productive laboratory time and engaged students. The results of the present study also suggest that if there is limited time available for palpation instruction, choosing cows with behavior allowing easy handling is important to the educational process.
Assuntos
Competência Clínica , Exame Retal Digital , Educação em Veterinária , Prenhez , Animais , Bovinos , Feminino , Gravidez , Exame Retal Digital/veterinária , Prenhez/fisiologiaRESUMO
Obstetrical chain placement requires location of specific landmarks and a certain dexterity that must be practiced. Use of low-fidelity models may not always provide students with a realistic experience. In this study we developed an anatomically correct high-fidelity calf leg model that would serve as a better teaching model for pre-clinical veterinary students than a pre-existing low-fidelity polyvinyl chloride (PVC) model. One hundred and twenty pre-clinical veterinary students were instructed how to use obstetrical chains with a low-fidelity PVC model and the anatomically correct high-fidelity calf leg model. After a 45-minute lab, students were surveyed on their experience with both models. Overall students felt the anatomically correct high-fidelity calf leg model increased accuracy in chain placement and provided more accurate landmarks, a more realistic model, and more real-life scenario training.
Assuntos
Anatomia Veterinária/educação , Bovinos/anatomia & histologia , Competência Clínica , Educação em Veterinária , Modelos Anatômicos , Animais , Animais Recém-Nascidos/anatomia & histologia , Humanos , Perna (Membro)/anatomia & histologia , Treinamento por SimulaçãoRESUMO
Negative density-dependent seedling mortality has been widely detected in tropical, subtropical and temperate forests, with soil pathogens as a major driver. Here we investigated how host density affects the composition of soil pathogen communities and consequently influences the strength of plant-soil feedbacks. In field censuses of six 1-ha permanent plots, we found that survival was much lower for newly germinated seedlings that were surrounded by more conspecific adults. The relative abundance of pathogenic fungi in soil increased with increasing conspecific tree density for five of nine tree species; more soil pathogens accumulated around roots where adult tree density was higher, and this greater pathogen frequency was associated with lower seedling survival. Our findings show how tree density influences populations of soil pathogens, which creates plant-soil feedbacks that contribute to community-level and population-level compensatory trends in seedling survival.
Assuntos
Fungos/classificação , Fungos/fisiologia , Doenças das Plantas/microbiologia , Plântula/microbiologia , Árvores/microbiologia , Densidade Demográfica , Microbiologia do SoloRESUMO
Global change is impacting forests worldwide, threatening biodiversity and ecosystem services including climate regulation. Understanding how forests respond is critical to forest conservation and climate protection. This review describes an international network of 59 long-term forest dynamics research sites (CTFS-ForestGEO) useful for characterizing forest responses to global change. Within very large plots (median size 25 ha), all stems ≥ 1 cm diameter are identified to species, mapped, and regularly recensused according to standardized protocols. CTFS-ForestGEO spans 25 °S-61 °N latitude, is generally representative of the range of bioclimatic, edaphic, and topographic conditions experienced by forests worldwide, and is the only forest monitoring network that applies a standardized protocol to each of the world's major forest biomes. Supplementary standardized measurements at subsets of the sites provide additional information on plants, animals, and ecosystem and environmental variables. CTFS-ForestGEO sites are experiencing multifaceted anthropogenic global change pressures including warming (average 0.61 °C), changes in precipitation (up to ± 30% change), atmospheric deposition of nitrogen and sulfur compounds (up to 3.8 g N m(-2) yr(-1) and 3.1 g S m(-2) yr(-1)), and forest fragmentation in the surrounding landscape (up to 88% reduced tree cover within 5 km). The broad suite of measurements made at CTFS-ForestGEO sites makes it possible to investigate the complex ways in which global change is impacting forest dynamics. Ongoing research across the CTFS-ForestGEO network is yielding insights into how and why the forests are changing, and continued monitoring will provide vital contributions to understanding worldwide forest diversity and dynamics in an era of global change.