Native diversity buffers against severity of non-native tree invasions.

Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species1,2. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies3,4. Here, leveraging global tree databases5-7, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions.

The number of tree species on Earth.

One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknown. Here, based on global ground-sourced data, we estimate the total tree species richness at global, continental, and biome levels. Our results indicate that there are ∼73,000 tree species globally, among which ∼9,000 tree species are yet to be discovered. Roughly 40% of undiscovered tree species are in South America. Moreover, almost one-third of all tree species to be discovered may be rare, with very low populations and limited spatial distribution (likely in remote tropical lowlands and mountains). These findings highlight the vulnerability of global forest biodiversity to anthropogenic changes in land use and climate, which disproportionately threaten rare species and thus, global tree richness.

Reading tea leaves worldwide: Decoupled drivers of initial litter decomposition mass-loss rate and stabilization.

The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large-scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass-loss rates and stabilization factors of plant-derived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy-to-degrade components accumulate during early-stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass-loss rates and stabilization, notably in colder locations. Using TBI improved mass-loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early-stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models.

Action observation plus motor imagery and somatosensory discrimination training are effective non-motor approaches to improve manual dexterity.

BACKGROUND: Action observation plus motor imagery (AOMI) and somatosensory discrimination training (SSDT) represent sensory input-based approaches to train the motor system without necessarily asking subjects to perform active movements. PURPOSE: To investigate AOMI and SSDT effects compared to no intervention on manual dexterity in healthy subjects. STUDY DESIGN: Randomized controlled study. METHODS: Sixty healthy right-handed participants were randomized into AOMI, SSDT or Control (CTRL) groups. AOMI observed video-clips including right-hand dexterity tasks and concurrently performed motor imagery, SSDT performed surfaces recognition and 2-point distance discrimination tasks with the right hand, whereas CTRL underwent no intervention. A blinded physiotherapist assessed participants for manual dexterity using the Purdue Pegboard Test (Right hand-R, Left hand-L, Both hands-B, R+L+B and assembly tasks) at baseline (T0) and training end (T1). A mixed-design Analysis of Variance with Time as within-subject factor and Group as between-subject factor was used to investigate between-group differences over time. RESULTS: A Time by Group interaction and Time effect were found for R task, which increased from T0 to T1 in all groups with very large effect sizes for SSDT (d = 1.8, CI95 2.4-1.0, P < .001) and AOMI (d = 1.7, CI95 2.5-1.0, P < .001) and medium effect size for CTRL (d = 0.6, CI95 1.2-0.2, P < .001). Between-group post-hoc comparison for deltas (T1-T0) showed large effect size (d = 1.0, CI95 1.6-0.3, P = .003) in favor of SSDT and medium effect size (d = 0.7, CI95 1.4-0.1, P = .026) in favor of AOMI compared to CTRL. Time effects were found for L, B, R + L + B and assembly tasks (P < .001). CONCLUSIONS: AOMI and SSDT induced greater manual dexterity improvements than no intervention. These findings supported the role of visual and somatosensory stimuli in building a motor plan and enhancing the accuracy of hand movements. These non-motor approaches may enhance motor performance in job or hobbies requiring marked manual dexterity.

Motor resonance to non-visible postural adaptation: A novel aspect of the mirror mechanism.

The activation of the Mirror Neuron System (MNS) has been described to reflect visible movements, but not postural, non-visible, adaptations that accompany the observed movements. Since any motor act is the result of a well-tailored dialogue between these two components, we decided to investigate whether a motor resonance to nonvisible postural adaptations could be detected. Possible changes in soleus corticospinal excitability were investigated by eliciting the H-reflex during the observation of three videos, corresponding to three distinct experimental conditions: 'Chest pass', 'Standing' and 'Sitting', and comparing its size with that measured during observation of a control videoclip (a landscape). In the observed experimental conditions, the Soleus muscle has different postural roles: a dynamic role in postural adaptations during the Chest pass; a static role while Standing still; no role while Sitting. The H-reflex amplitude was significantly enhanced in the 'Chest pass' condition compared to the 'Sitting' and 'Standing' conditions. No significant difference was found between 'Sitting' and 'Standing' conditions. The increased corticospinal excitability of the Soleus during the 'Chest pass' condition suggests that the mirror mechanisms produce a resonance to postural components of an observed action, although they may not be visible. This observation highlights the fact that mirror mechanisms echo non intentional movements as well and points to a novel possible role of mirror neurons in motor recovery.

A multitaxonomic assessment of Natura 2000 effectiveness across European biogeographic regions.

The Natura 2000 (N2K) protected area (PA) network is a crucial tool to limit biodiversity loss in Europe. Despite covering 18% of the European Union's (EU) land area, its effectiveness at conserving biodiversity across taxa and biogeographic regions remains uncertain. Testing this effectiveness is, however, difficult because it requires considering the nonrandom location of PAs, and many possible confounding factors. We used propensity score matching and accounted for the confounding effects of biogeographic regions, terrain ruggedness, and land cover to assess the effectiveness of N2K PAs on the distribution of 1769 species of conservation priority in the EU's Birds and Habitats Directives, including mammals, birds, amphibians, reptiles, arthropods, fishes, mollusks, and vascular and nonvascular plants. We compared alpha, beta, and gamma diversity between matched selections of protected and unprotected areas across EU's biogeographic regions with generalized linear models, generalized mixed models, and nonparametric tests for paired samples, respectively, for each taxonomic group and for the entire set of species. PAs in N2K hosted significantly more priority species than unprotected land, but this difference was not consistent across biogeographic regions or taxa. Total alpha diversity and alpha diversity of amphibians, arthropods, birds, mammals, and vascular plants were significantly higher inside PAs than outside, except in the Boreal biogeographical region. Beta diversity was in general significantly higher inside N2K PAs than outside. Similarly, gamma diversity had the highest values inside PAs, with some exceptions in Boreal and Atlantic regions. The planned expansion of the N2K network, as dictated by the European Biodiversity Strategy for 2030, should therefore target areas in the southern part of the Boreal region where species diversity of amphibians, arthropods, birds, mammals, and vascular plants is high and species are currently underrepresented in N2K.

Análisis multitaxonómico de la efectividad de Natura 2000 en las regiones biogeográficas de Europa Resumen La red de áreas protegidas (AP) de Natura 2000 (N2K) es una herramienta importante para reducir la pérdida de biodiversidad en Europa. A pesar de que cubre el 18% del área terrestre de la UE, todavía es incierta la efectividad que tiene para conservar la biodiversidad en los taxones y las regiones biogeográficas. Sin embargo, es complicado analizar esta efectividad porque requiere considerar la ubicación no azarosa de las AP y la posibilidad de muchos factores confusos. Usamos el pareamiento por puntaje de propensión y consideramos los efectos confusos de las regiones biogeográficas, lo accidentado del terreno y la cobertura del suelo para analizar la efectividad de las AP de N2K en la distribución de 1,769 especies (mamíferos, aves, anfibios, reptiles, artrópodos, peces, moluscos y plantas vasculares y no vasculares) con prioridad de conservación en las Directivas de Aves y Hábitats de la UE. Comparamos la diversidad alfa, beta y gamma entre las selecciones pareadas de las áreas protegidas y no protegidas en las regiones biogeográficas de la UE con los modelos generalizados lineales, mixtos y pruebas no paramétricas de las muestras pareadas, respectivamente, para cada grupo taxonómico y para el conjunto completo de especies. Las áreas protegidas en N2K tuvieron una mayoría significativa de especies prioritarias en comparación con el suelo no protegido, pero esta diferencia no fue coherente entre los taxones y las regiones biogeográficas. La diversidad alfa total y la diversidad alfa de anfibios, artrópodos, aves, mamíferos y plantas vasculares fue significativamente mayor dentro de las AP que fuera de ellas, excepto en la región biogeográfica boreal. La diversidad beta fue significativamente más alta dentro de las AP de N2K que fuera de ellas. De forma similar, la diversidad gamma tuvo los valores más altos dentro de las AP, salvo algunas excepciones en las regiones boreal y atlántica. Por lo tanto, la expansión planeada de la red N2K, como dicta la Estrategia de la UE sobre Biodiversidad para 2030, debería enfocarse en las áreas del sur de la región boreal, donde es alta la diversidad de especies de anfibios, artrópodos, aves, mamíferos y plantas vasculares y cuyas especies están poco representadas dentro de N2K.

Kinematic evaluation and reliability assessment of the Nine Hole Peg Test for manual dexterity.

BACKGROUND: The Nine Hole Peg Test (NHPT) is one of the most frequently used tools to assess manual dexterity. However, no kinematic parameters are provided to describe the quality of the motor performance, since time is the only score. PURPOSE: To investigate test-retest and intra-rater reliability, correlation with clinical test score, and discriminant validity of kinematic indexes during NHPT. STUDY DESIGN: A clinical measurement study. METHODS: Twenty-five healthy right-handed volunteers performed the NHPT. An experienced physiotherapist administered two sessions at a 6-hour interval with two trials for dominant and non-dominant upper limbs. An optoelectronic system was used to detect NHPT performance, which was divided into nine consecutive peg-grasp, peg-transfer, peg-in-hole, hand-return phases, and one final removing phase. Outcome measures were total and single phases times, normalized jerk, mean, peak and time-to-peak of velocity, curvature index during peg-grasp and hand-return phases, and trunk 3D displacement. The statistical analysis included Intraclass Correlation Coefficients (ICCs) for test-retest and intra-rater reliability, Pearson's coefficients for correlation with the NHPT score, and paired t-tests for discriminant validity. RESULTS: Test-retest reliability was excellent for trunk rotation (ICC: 0.91) and good to moderate for the other indexes (ICCs: 0.89-0.61). Intra-rater reliability was excellent for total and removing times (ICCs: 0.91 and 0.94) and good to moderate for the other indexes (ICCs: 0.84-0.66), except for trunk inclination (ICC: 0.37). NHPT phases, normalized jerk, mean velocity, peak of velocity, time-to-peak and curvature index correlated with total time (r-score: 0.8-0.3). NHPT phases and most kinematic indexes discriminated the dominant from non-dominant upper limb, with the greatest effect size for normalized jerk during hand-return (d = 1.16). CONCLUSIONS: Kinematic indexes during NHPT can be considered for manual dexterity assessment. These indexes may allow for the detection of kinematic changes responsible for NHPT score variations in healthy subjects or patients with upper limb impairments.

Reliability of Shoulder Helical Axes During Intransitive and Transitive Upper Limb Tasks.

Shoulder complex stability can be estimated in vivo through the analysis of helical axes (HAs) dispersion during upper limb movements. The study aimed at investigating test-retest reliability of shoulder HAs dispersion parameters during upper limb tasks. Twenty healthy volunteers performed 2 intransitive (shoulder flexion and rotation) and one transitive (combing) tasks with the dominant and nondominant upper limbs during 2 recording sessions at 1-week distance. Kinematics was detected through an optoelectronic system. Mean distance and mean angle (MA) were adopted as HAs dispersion indexes. Reliability was excellent for mean distance (intraclass correlation coefficient [ICC]: .91) and MA (ICC: .92) during dominant flexion, and good for MA (ICC: .90) during nondominant flexion. Moderate reliability was found for HAs parameters during rotation (ICCs from .70 to .59), except for MA during dominant rotation where reliability was poor. Reliability was good for mean distance (ICC: .83) and moderate for MA (ICC: .67) during the dominant combing task, whereas no reliability was found during the nondominant combing task. HAs dispersion parameters revealed high reliability during simple intransitive tasks with the dominant limb. Reliability decreased with the increase in task complexity due to the increase in movement variability. HAs dispersion technique could be used to assess shoulder complex stability in patients after rehabilitation or surgery.

Mapping brain structure and function in professional fencers: A model to study training effects on central nervous system plasticity.

Brain magnetic resonance imaging (MRI) studies have shown different patterns of structural and functional reorganization in high-level athletes compared with controls, but little is known about their relationship with interlimb coordination mechanisms. To this aim, we investigated brain structural and functional differences in high-level fencers compared with nonathlete controls and the MRI substrates of interlimb coordination in elite athletes. Fourteen right-handed male fencers (median age = 22.3 years) and 15 right-handed age- and sex-matched healthy subjects (median age = 22.4 years) underwent structural and functional MRI acquisition during the execution of cyclic bimanual-movements as well as during in-phase and antiphase hand/foot-movements of the dominant-right limbs. No between-group differences were found in gray matter volumes and white matter architecture. Active-fMRI showed that controls versus fencers had higher activations in parietal and temporal areas during bimanual-task; whereas fencers versus controls had higher activations in the basal ganglia. During in-phase task, controls versus fencers showed higher activation of right cerebellum, whereas fencers had higher activity mainly in frontal areas. The functional-connectivity (FC) analysis showed that fencers versus controls had an increased FC between left motor cortex and fronto-temporal areas as well as bilateral thalami during the different tasks. Intensive and prolonged fencing activity is associated with brain functional changes mainly involving frontal regions related to high-level motor control and planning of complex tasks. These modifications are likely to reflect an optimization of brain networks involved in motor activities, including interlimb coordination tasks, occurring after intensive training.