Characterizing functional trait variation and covariation, and its drivers, is critical to understand the response of species to changing environmental conditions. Evolutionary and environmental factors determine how traits vary among and within species at multiple scales. However, disentangling their relative contribution is challenging and a comprehensive trait-environment framework addressing such questions is missing in lichens. We investigated the variation in nine traits related to photosynthetic performance, water use and nutrient acquisition applying phylogenetic comparative analyses in lichen epiphytic communities on beech across Europe. These poikilohydric organisms offer a valuable model owing to their inherent limitations to buffer contrasting environmental conditions. Photobiont type and growth form captured differences in certain physiological traits whose variation was largely determined by evolutionary processes (i.e. phylogenetic history), although the intraspecific component was non-negligible. Seasonal temperature fluctuations also had an impact on trait variation, while nitrogen content depended on photobiont type rather than nitrogen deposition. The inconsistency of trait covariation among and within species prevented establishing major resource use strategies in lichens. However, we did identify a general pattern related to the water-use strategy. Thus, to robustly unveil lichen responses under different climatic scenarios, it is necessary to incorporate both among and within-species trait variation and covariation.

Objective: To investigate the release of progastrin-releasing peptide (ProGRP) in patients with thyroid nodules and the value of ProGRP in fine-needle aspirate washout fluid (FNA-ProGRP) in the differential diagnosis between medullary thyroid carcinoma (MTC) and non-MTC thyroid nodules.Methods: We investigated 2,446 healthy persons and 212 patients with 235 thyroid nodules. They were classified into healthy, nodular goiter, chronic thyroiditis, thyroid follicular neoplasm, papillary thyroid carcinoma, follicular thyroid carcinoma, and medullary thyroid carcinoma. The serum ProGRP and FNA-ProGRP were measured.Results: The serum ProGRP median concentration in MTC was 124.40 pg/mL, significantly higher than in other groups. The cutoff value of serum ProGRP was 68.30 pg/mL, leading to 53.85% sensitivity, 96.98% specificity, and 0.51 kappa value in MTC. The FNA-ProGRP median concentration in MTC nodules was 2,096.00 pg/mL, significantly higher than in other groups. A receiver operating characteristic analysis of MTC nodules and non-MTC nodules indicated that the cutoff value was 22.77 pg/mL, leading to 94.12% sensitivity, 98.27% specificity, and 0.85 kappa value.Conclusion: FNA-ProGRP measurement could be served as an ancillary method for the differential diagnosis between MTC and non-MTC thyroid nodules.Abbreviations: CEA = carcinoembryonic antigen; CT = calcitonin; FNAC = fine-needle aspiration cytology; FNA-CT = calcitonin in fine-needle aspirate washout fluid; FNA-ProGRP = ProGRP in fine-needle aspirate washout fluid; MTC = medullary thyroid carcinoma; ProGRP = progastrin-releasing peptide; SCLC = small-cell lung cancer; TM = tumor marker

BACKGROUND AND AIMS:In order to re-establish lichen symbiosis, fungal spores must first germinate and then associate with a compatible photobiont. To detect possible establishment limitations in a sexually reproducing cyanolichen species, we studied ascospore germination, photobiont growth and photobiont association patterns in Pectenia plumbea.METHODS:Germination tests were made with ascospores from 500 apothecia under different treatments, and photobiont growth was analysed in 192 isolates obtained from 24 thalli. We determined the genotype identity [tRNALeu (UAA) intron] of the Nostoc cyanobionts from 30 P. plumbea thalli from one population. We also sequenced cyanobionts of 41 specimens of other cyanolichen species and 58 Nostoc free-living colonies cultured from the bark substrate.KEY RESULTS:Not a single fungal ascospore germinated and none of the photobiont isolates produced motile hormogonia. Genetic analyses revealed that P. plumbea shares Nostoc genotypes with two other cyanolichen species of the same habitat, but these photobionts were hardly present in the bark substrate.CONCLUSIONS:Due to the inability of both symbionts to thrive independently, the establishment of P. plumbea seems to depend on Dendriscocaulon umhausense, the only cyanolichen species in the same habitat that reproduces asexually and acts as a source of appropriate cyanobionts. This provides support to the hypothesis about facilitation among lichens.

Background Systemic lupus erythematous (SLE) is an autoimmune disease characterised by deregulation of cytokine production. INF1A is a proinflamatory cytokine considered as a key molecule in the SLE etiopathogenesis, being responsible indirectly of IL10 upregulation. BLyS is involved in autoantibodies production and clinical activity in SLE, and its expression is regulated by other cytokines as IL10 and INF1A. IL2 is an anti-inflammatory cytokine in SLE, but its loss leads to the production of Th2 proinflammatory cytokines as IL4, IL5 and IL13. Objectives To analyse the association among inflammatory cytokine levels and clinical activity, as well as to identify a cytokine profile related to disease activity in SLE. Methods A cross-sectional, observational study of 142 patients diagnosed of SLESLICC 2012 criteria), and 35 healthy controls, was performed. A complete blood-test and an interview were carried out to collect their clinical data. We analysed inflammatory cytokines serum levels by colorimetric methods. Biostatistical analysis with R was performed. Results Mean cytokine levels for the SLE patients and healthy controls are shown in the table 1. The mean clinical activity measured by SLEDAI was 5.91±5.06, and we observed a statistically significant association between high levels of IL10 and high clinical activity (p=0.001). Statistical analysis indicates that complement consumption is associated with increased levels of IL10 (p=0.029), INF1A (p<0.001), IL4 (p=0.004), IL5 (p=0.009) and decreased levels of IL2 (p=0.045),; or anti-DNA positivity is associated with increased levels of INF1A (p=0.002) and decreased levels of IL2 (p=0.045), IL4 (p=0.034) and IL5 (p=0.007). Moreover, BLyS seems to have increased in patients with positive antiphospholipid antibodies and anti-DNA. IL10 is associated with ENAs positivity (p=0.022). In patients with other autoimmune disease associated with SLE, an increase of INF1A (p=0.008) and IL5 (p=0.044) is observed. SLE patients were categorised by normal, low or high level of the eight citokines. Despite the fact that no specific cytokine profile associated with clinical activity was observed, those patients with high SLEDAI score had increased levels of IL10 and INF1A and decreased levels of IL2 and IL21. Conclusions Our SLE patients displayed mainly IL10, INF1A and BLyS increased, and IL2 decreased. Although IL10 seems to be the cytokine which best fits to clinical activity in SLE, altered levels of INF1A, IL2, IL4, and IL5 are associated with complement consumption or anti-DNA positivity. Disclosure of Interest None declared

Existen diversas evidencias que indican que los déficits motores en los pacientes de parálisis cerebral se asocian con problemas en la planificación motora que, a su vez, apuntan a una mermada capacidad para imaginar movimientos. La imaginación motora se ha revelado como una herramienta efectiva en el aprendizaje y la adquisición de habilidades motoras ya que comparte estructuras neuronales similares con la ejecución motora. En este trabajo se presenta un paradigma basado en un juego de realidad virtual para guiar la actividad mental del paciente que sirve a dos fines: estudiar su capacidad de imaginar movimientos e implicar y motivar al paciente en el entrenamiento de dicha capacidad. El estudio ha involucrado cuatro niños con parálisis cerebral espástica (edad media = 13.25 años, DS = 1.5) con lesión cerebral bilateral. Los resultados obtenidos del análisis de su actividad electroencefalográfica muestran que estos pacientes son capaces de emplear la imaginación motora en una tarea de marcha, indicada por la presencia del fenómeno ERD (Event Related Desynchronization) en zonas corticales motoras, independientemente de su nivel funcional y de los miembros afectados.

La leucemia mieloblástica aguda (LMA) constituye la segunda hemopatía maligna en la población pediátrica y una de las principales causas de mortalidad por cáncer infantil. La supervivencia se sitúa alrededor del 60% sin haber mejorado en las últimas décadas, por lo que son necesarios nuevos enfoques terapéuticos. El efecto antileucémico ejercido por los linfocitos y las células natural killer (NK) del sistema inmunológico está bien establecido en el trasplante de células madre hematopoyéticas pero también como estrategia de inmunoterapia adoptiva tras la quimioterapia de consolidación. De manera retrospectiva, se analizan las características clínicas de los pacientes diagnosticados de LMA en nuestro centro durante el período 1996-2014. Además en 10 leucemias agudas, 5 linfoides y 5 mieloides, se analizaron la intensidad media de fluorescencia de HLA-I, MICA-B, ULBP1-4, ligandos para los receptores de las células NK. Un total de 67 pacientes formaron parte de este análisis. La supervivencia libre de eventos con una mediana de seguimiento de 25 meses fue del 62% (IC del 95%, 55-67). Las LMA con menor supervivencia fueron las secundarias, las no M3 y las carentes de marcadores citogenéticos favorables. La probabilidad de recaída fue del 38% (IC del 95%, 31-45). La expresión de HLA-I y ULBP-4 fue significativamente menor en los blastos mieloides que en los linfoides. Nuestros resultados clínicos son similares a los descritos en la literatura. No se ha modificado significativamente la supervivencia en las últimas décadas y la probabilidad de recaída sigue siendo elevada. Los blastos mieloides podrían ser más susceptibles a las células NK al expresar menos HLA-I, por lo que estrategias de terapia celular podrían ser eficaces tal y como reportan otros grupos. Acute myeloid leukaemia (AML) is the second haematological malignancy in the paediatric population, and one of the leading causes of childhood cancer mortality. Survival is currently around 60%, with no improvement in last decades, suggesting that new therapeutic approaches are needed. The anti-leukaemia effect mediated by the lymphocytes and natural killer (NK) cells of the immune system has been established in haematopoietic stem cell transplantation, and also as adoptive immunotherapy after consolidation chemotherapy schemes. A retrospective study was conducted on the clinical characteristics of patients diagnosed and treated for AML in our centre during 1996-2014. The mean fluorescence intensities of HLA-I, MICA/B and ULBP1-4, ligands for NK cell receptors, were also analysed in ten new diagnosed leukaemia cases, five myeloid and five lymphoid. A total of 67 patients were used in this analysis. With a median follow up of 25 months, the event-free survival was 62% (95% CI: 55-67). Secondary AML, non-M3 phenotype, and the absence of favourable cytogenetic markers had a lower survival. The probability of relapse was 38% (95% CI: 31-45). The expression of HLA-I and ULBP-4 was significantly lower in myeloid than in lymphoid blast cells. Our clinical results are similar to those described in the literature. Survival did not significantly change in recent decades, and the likelihood of relapse remains high. Myeloid blasts might be more susceptible to the cytotoxicity of NK cells through their lower expression of HLA-I. NK therapy strategies in minimal disease situation could be effective, as reported by other groups.

Background Pregnancy in rheumatic diseases is a process that requires careful handling, beginning with proper planning. Infertility and chronic use of teratogenic drugs are some common situations in these patients, giving them a high-risk obstetrics. Objectives To established a protocol for planning and monitoring pregnancies in patients with rheumatic diseases Methods Retrospective review of a follow-up protocol for patients with rheumatic diseases and pregnancy wishes. This protocol includes: preconception consultation to asses fertility of the couple, as well as pregnancy couselling and establishment of a appropriate pharmacological treatment; after pregnancy period start, monthly consultations by a multidisciplinary team; and finally, a postpartum consultation after delivery Results A total of 51 patient with different rheumatic diseases were included: Sistemic Lupus Erythematosus (8 patients), Sjogren9S Syndrom (10 patients), Rheumatoid arthritis (13 patients), Psoriatic arthritis (5 patients), Behcet9s disease (3 patients), Spondiloarthritis (2 patients), Familial Mediterranean Fever (2 patients), Conective mixed Tissues Disease (1 patient), Primary Antiphospholipi Syndrom (2 patient) an Hyper IgD Syndrome (1 patient). The results were: Infertility was detected in 8 couples and assisted reproductive techniques was requieres in 7 (6 IVF and 1 insemination). Safe Pharmacological treatments were used: sulfasalazine (4), hydroxychloroquine (13), azathioprine (2). Biological DMARDs in 3 patients (1 infliximab and Certlizumab in 2). Other treatments were: steroids (12) and intravenosus immunoglobulins for fetal heart block (2). All patients with thrombophilia have been treated with LMWH alone or plus aspirin. The course of pregnancy was:delivery at term (28), delivery pre-term (3)**, miscariages (3)*, pregnancy on course (7), neonatal death (1) and 8 patients are plannig the pregnancy. The abortions have occurred in 2 patients with lupus erythematosus and in 1 patient with rheumatoid arthritis. Postpartum care of newborns with mothers with positivity anti-Ro has objectified a neonatal transfer of Acs in 100% of cases;only 8 of them developed neonatal SLE. Conclusions A satisfactory evolution of pregnancy was observed in 87% of our patients, a fact that supports our impression that this process should be approached in a multidisciplinary team. Infertility is a situation that should be considered and treated at an early stage in this patients, preferably before preconceptional period. Disclosure of Interest None declared

Cerebral Palsy (CP) is a disorder of posture and movement due to a defect in the immature brain. The use of robotic devices as alternative treatment to improve the gait function in patients with CP has increased. Nevertheless, current gait trainers are focused on controlling complete joint trajectories, avoiding postural control and the adaptation of the therapy to a specific patient. This paper presents the applicability of a new robotic platform called CPWalker in children with spastic diplegia.

Cerebral Palsy (CP) is a disorder of posture and movement due to an imperfection or lesion in the immature brain. CP is often associated to sensory deficits, cognition impairments, communication and motor disabilities, behaviour issues, seizure disorder, pain and secondary musculoskeletal problems. New strategies are needed to help to promote, maintain, and rehabilitate the functional capacity, and thereby diminish the dedication and assistance required and the economical demands that this condition represents for the patient, the caregivers and the whole society. This paper describes the conceptualization and development of the integrated CPWalker robotic platform to support novel therapies for CP rehabilitation. This platform (Smart Walker + exoskeleton) is controlled by a multimodal interface to establish the interaction of CP children with robot-based therapies. The objective of these therapies is to improve the physical skills of children with CP and similar disorders. CPWalker concept will promote the earlier incorporation of CP patients to the rehabilitation therapy and increase the level of intensity and frequency of the exercises according to the task, which will enable the maintenance of therapeutic methods in daily basis, with the intention to lead to significant improvements in the treatment outcome.

Introduction: Acute myeloid leukaemia (AML) is the second haematological malignancy in the paediatric population, and one of the leading causes of childhood cancer mortality. Survival is currently around 60%, with no improvement in last decades, suggesting that new therapeutic approaches are needed. The anti-leukaemia effect mediated by the lymphocytes and natural killer (NK) cells of the immune system has been established in haematopoietic stem cell transplantation, and also as adoptive immunotherapy after consolidation chemotherapy schemes.Patients and methods: A retrospective study was conducted on the clinical characteristics of patients diagnosed and treated for AML in our centre during 1996-2014. The mean fluorescence intensities of HLA-I, MICA/B and ULBP1-4, ligands for NK cell receptors, were also analysed in ten new diagnosed leukaemia cases, five myeloid and five lymphoid.Results: A total of 67 patients were used in this analysis. With a median follow up of 25 months, the event-free survival was 62% (95% CI: 55-67). Secondary AML, non-M3 phenotype, and the absence of favourable cytogenetic markers had a lower survival. The probability of relapse was 38% (95% CI: 31-45). The expression of HLA-I and ULBP-4 was significantly lower in myeloid than in lymphoid blast cells.Conclusions: Our clinical results are similar to those described in the literature. Survival did not significantly change in recent decades, and the likelihood of relapse remains high. Myeloid blasts might be more susceptible to the cytotoxicity of NK cells through their lower expression of HLA-I. NK therapy strategies in minimal disease situation could be effective, as reported by other groups. (C) 2015 Asociacion Espanola de Pediatria. Published by Elsevier Espana, S.L.U. All rights reserved.

Haploidentical hematopoietic stem cell transplantation using T-cell-depleted grafts is a valid option for pediatric patients with hematological malignancies in need of an allogeneic transplantation and lacking an HLA-identical donor. Seventy-five transplantations were performed in 70 patients. Thirty-eight patients had ALL, 32 had AML, 3 had advanced myelodysplastic syndromes and 2 juvenile myelomonocytic leukemia; 19 were in first CR, 30 in second CR, 12 in greater than second CR and 14 were considered to be in refractory disease at time of transplantation. Four patients developed graft failure. Among engrafted patients, the median time to neutrophil and platelet recovery was 13 (range 8–20) and 10 days (range 8–70), respectively. In 64 (85%) cases, ⩾1 infections were diagnosed after transplant. The probability of nonrelapse mortality by day +100 after transplantation was 10±4%. With a median follow-up of 22 months, the probability of relapse was 32±6% and disease-free survival was 52±6%. Haploidentical transplantation using CD3/CD19 depletion is associated with encouraging results especially in patients in early phase of disease. Killer-cell Ig-like receptor B haplotype donors confer a rapid natural killer cells expansion early after transplantation, resulting in lower probability of relapse and suggesting a GvL effect apart from graft-versus-host reactions. Donor infusion of high numbers of CD34+ cells is recommended in order to improve T-cell reconstitution.

PURPOSE:Acute mesenteric ischaemia (AMI) accounts for about 1:1000 acute hospital admissions. Untreated, AMI will cause mesenteric infarction, intestinal necrosis, an overwhelming inflammatory response and death. Early intervention can halt and reverse this process leading to a full recovery, but the diagnosis of AMI is difficult and failure to recognize AMI before intestinal necrosis has developed is responsible for the high mortality of the disease. Early diagnosis and prompt treatment are the goals of modern therapy, but there are no randomized controlled trials to guide treatment and the published literature contains a high ratio of reviews to original data. Much of that data comes from case reports and often small, retrospective series with no clearly defined treatment criteria. METHODS:A study group of the European Society for Trauma and Emergency Surgery (ESTES) was formed in 2013 with the aim of developing guidelines for the management of AMI. A comprehensive literature search was performed using the Medical Subject Heading (MeSH) thesaurus keywords "mesenteric ischaemia", "bowel ischaemia" and "bowel infarction". The bibliographies of relevant articles were screened for additional publications. After an initial systematic review of the literature by the whole group, a steering group formulated questions using a modified Delphi process. The evidence was then reviewed to answer these questions, and recommendations formulated and agreed by the whole group. RESULTS:The resultant recommendations are presented in this paper. CONCLUSIONS:The aim of these guidelines is to provide recommendations for practice that will lead to improved outcomes for patients.

Integrin αIIbβ3 is a member of the integrin family of transmembrane proteins present on the plasma membrane of platelets. Integrin αIIbβ3 is widely known to regulate the process of thrombosis via activation at its cytoplasmic side by talin and interaction with the soluble fibrinogen. It is also reported that three groups of interactions restrain integrin family members in the inactive state, including a set of salt bridges on the cytoplasmic side of the transmembrane domain of the integrin α- and β-subunits known as the inner membrane clasp, hydrophobic packing of a few transmembrane residues on the extracellular side between the α- and β-subunits that is known as the outer membrane clasp, and the key interaction group of the βA domain (located on the β-subunit head domain) with the βTD (proximal to the plasma membrane on the β-subunit). However, molecular details of this key interaction group as well as events that lead to detachment of the βTD and βA domains have remained ambiguous. In this study, we use molecular dynamics models to take a comprehensive outside-in and inside-out approach at exploring how integrin αIIbβ3 is activated. First, we show that talin’s interaction with the membrane-proximal and membrane-distal regions of integrin cytoplasmic-transmembrane domains significantly loosens the inner membrane clasp. Talin also interacts with an additional salt bridge (R734-E1006), which facilitates integrin activation through the separation of the integrin’s α- and β-subunits. The second part of our study classifies three types of interactions between RGD peptides and the extracellular domains of integrin αIIbβ3. Finally, we show that the interaction of the Arg of the RGD sequence may activate integrin via disrupting the key interaction group between K350 on the βA domain and S673/S674 on the βTD.

Background Primary pyomyositis is a rare condition in children that should be included in the differential diagnosis of musculoskeletal infections. Objectives To describe the clinical features of pyomyositis as well as its diagnostic and therapeutic approach. Methods A descriptive and retrospective study was performed by reviewing medical records of patients admitted to our hospital from January 1996 to July 2013 with a diagnosis of primary pyomyositis. Results A total of 25 patients (16 men, 9 women) aged between one month and 14 years (median age 2 years) were registered. Two peaks of incidence have been found in the months of July and October. The most frequent clinical manifestations were the presence of local pain (24 patients), fever (18 patients), local swelling (9 patients) and skin rash (7 patients). Predisposing factors in 8 patients (1 strenuous exercise, 4 trauma, 3 intramuscular injections) were found. The primary site was pelvic muscles or lower extremities (20 patients). In laboratory results, we found the presence of leukocytosis, with an average value of 12,936±5.753/uL leukocytes, total neutrophils 4.659/uL ±7.350), ESR of 55±28 mm) and PCR 8±6 mg/dL). CPK was normal in 5 out of 6 patients who were requested. Laboratory results were positive for Staphylococcus aureus (7 patients), Salmonella no tiphy (1 patient) and Bacteroides fragillis (1 patient). Ultrasound suggested the diagnosis in 11 cases and magnetic resonance imaging support the diagnosis in all cases. All patients received intravenous antibiotic therapy (mean duration 11 days) followed by oral antibiotic therapy (mean duration 23 days). 9 patients suffered complications as abscess formation, 3 need abscess aspiration and one of them required surgical drainage. None of our patients had residual functional limitations. Conclusions It is important to have a high index of suspicion for pyomyositis in patients with fever and musculoskeletal pain at an early stage in order to initiate start appropriate antibiotic treatment against Staphylococcus aureus. Although ESR and ultrasound may be useful, it is necessary to complement with magnetic resonance imaging in order to support the diagnosis in all cases. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.4467

Current data suggest that at least three psychophysiological paradigms are involved in Alcohol Dependence: attentional bias; affective modulation of the startle reflex and behavioural inhibition. These three paradigms have not been studied together in a sample of alcohol dependent subjects. To show that the performance on these three psychophysiological processes allows discriminating alcohol dependent subjects (with different severity) from healthy controls. 59 alcohol dependent subjects were assessed with the following three psychophysiological tasks: The dot probe task (which assesses attentional bias), the startle response when viewing alcohol cues (which evaluates affective modulation of the startle reflex), and the Modified- Stop Signal-Task (which measures behavioral inhibition). The Severity of Alcohol Dependence Scale (SAD) was used for grouping patients based on their dependence severity. 52 healthy subjects were assessed as the control group. All three paradigms correctly discriminated between patients and controls. Patients were divided into three subgroups according to their scores on the SAD (mild, moderate and severe dependence). The performance of the three groups in the three paradigms studied was also different. Patients with more severe dependence had more attentional bias for alcohol cues, exhibited lower magnitudes of startle response when viewing alcohol cues, and showed lower capacity to inhibit their behaviour when words related to alcohol were being seen. Subjects with alcohol dependence showed different psychophysiological response patterns compared to controls in the three paradigms studied. These response patterns seem to be associated with the severity of dependence, and they could be used to determine the outcome of the treatment in patients with alcohol dependence.

Grazing represents one of the most common disturbances in drylands worldwide, affecting both ecosystem structure and functioning. Despite the efforts to understand the nature and magnitude of grazing effects on ecosystem components and processes, contrasting results continue to arise. This is particularly remarkable for the biological soil crust (BSC) communities (i.e., cyanobacteria, lichens, and bryophytes), which play an important role in soil dynamics. Here we evaluated simultaneously the effect of grazing impact on BSC communities (resistance) and recovery after livestock exclusion (resilience) in a semiarid grassland of Central Mexico. In particular, we examined BSC species distribution, species richness, taxonomical group cover (i.e., cyanobacteria, lichen, bryophyte), and composition along a disturbance gradient with different grazing regimes (low, medium, high impact) and along a recovery gradient with differently aged livestock exclosures (short-, medium-, long-term exclusion). Differences in grazing impact and time of recovery from grazing both resulted in slight changes in species richness; however, there were pronounced shifts in species composition and group cover. We found we could distinguish four highly diverse and dynamic BSC species groups: (1) species with high resistance and resilience to grazing, (2) species with high resistance but low resilience, (3) species with low resistance but high resilience, and (4) species with low resistance and resilience. While disturbance resulted in a novel diversity configuration, which may profoundly affect ecosystem functioning, we observed that 10 years of disturbance removal did not lead to the ecosystem structure found after 27 years of recovery. These findings are an important contribution to our understanding of BCS dynamics from a species and community perspective placed in a land use change context.

The main factors determining the occurrence, abundance, growth and reproductive capacity of threatened lichens need to be known in order to implement conservation initiatives. The main objective of the present study was to evaluate which factors affect the conservation status of Degelia species-complex in central Spain. We undertook a non-parametric analysis to evaluate whether population sizes are larger in protected areas. We fitted generalized linear models (GLM) and mixed models (GLMMs) to analyze which variables are driving occurrence and abundance of Degelia, the thallus size and reproduction capacity. Results show that population sizes of Degelia are very variable, being larger in broad-leaved evergreen forests and inside protected areas. Tree characteristics play an important role in its local dynamics.

Morphological and physiological characteristics of biological soil crusts (BSCs) enhance soil stability and fertility, and influence soil chemistry. However, the effect of BSCs on soil physico-chemical properties may vary depending on taxa (cyanobacteria, lichen, bryophytes) and species, and be susceptible to soil surface disturbance. We examined a wide variety of soil physico-chemical properties associated with five BSC components (cyanobacteria crust, one moss species, three lichen species) naturally occurring in the study area, and bare soil along a disturbance gradient in a semiarid grassland ecosystem in Central Mexico. We addressed the following questions: 1) Do different BSC components create distinct soil microsites characterized by a particular combination of physico-chemical properties? 2) Do distinct soil properties change beneath different BSC components? 3) Does grazing disturbance modify or override species-specific BSC effects? We found that BSC components and bare soil generated distinct soil microsites, however, this effect diminished with increasing grazing pressure. Also, most of the soil variables examined differed between BSC components and bare soil along the gradient. While soil properties associated with cyanobacteria were relatively similar compared to bare soil along the gradient, Diploschistes diacapsis and Lecidella sp. showed decreases in pH and marked differences in mineral nutrient concentration (i.e. variations in Na, Fe and Zn concentration respect to other BSC components and bare soil). Grazing intensity and frequency changed species-specific effects of D. diacapsis, specially modifying its effect on soil texture, diminishing its effect on pH, K and Na concentration, and increasing its effect on Ca and Zn concentration. We conclude that BSC components contribute to natural small-scale soil heterogeneity, and that soil disturbance substantially modifies the nature and magnitude of this effect with potentially important implications on ecosystem processes. Because of the potential influence of other factors (i.e. climate, vascular plants, microbial activity) on BSCs' relation to soil properties, this assertion should be tested including these factors and in multiple ecosystems. (C) 2013 Elsevier Ltd. All rights reserved.

La costra biológica del suelo (CBS) es un componente complejo del ecosistema que engloba diferentes organismos (líquenes, musgos, hepáticas, cianobacterias, hongos, algas) presentes en las primeras capas de suelo. La CBS se encuentra en una amplia variedad de ecosistemas, aunque generalmente es más abundante en ecosistemas donde la cobertura de plantas vasculares es escasa, como los ecosistemas áridos. En estos eco-sistemas, la CBS contribuye considerablemente a su biodiversidad y funcionamiento. Debido a la gran dificultad para la identificación de especies de estas comunidades, la mayoría de la investigación sobre la CBS se ha desarrollado a escala de comunidad y grupo morfológico. A este nivel, se ha podido observar el gran potencial de estas comunidades de contribuir a la estructura y dinámica del ecosistema: interaccionan con las primeras capas del suelo y con otros organismos, participan en la fijación de carbono y nitrógeno, así como en procesos hidrológicos y en el ciclo de nutrientes. Sin embargo, avances recientes en el conocimiento de la CBS arrojan interesantes y marcadas diferencias en la ecología y el papel funcional de las distintas especies que la componen, con las consecuentes implicaciones en la gestión y conservación de estas comunidades y de los ecosistemas que habitan. En particular, se han observado respuestas específicas en términos de presencia, abundancia y frecuencia ante diversos factores ambientales (variables climáticas, tipo de sustrato, presencia de plantas vasculares y perturbación por pastoreo – recuperación natural), así como un efecto a nivel de especie sobre las propiedades del suelo.