Plant Richness Research Articles

Riqueza y uso de la flora medicinal de la Región Cajamarca (Norte del Perú): Un compendio de 1988 a 2022

Information on the richness and use of medicinal plants in the Cajamarca Region (RC), Peru, was compiled and analyzed in 49 studies, carried out from 1988 to 2022. Botanical information, altitudinal distribution, endemisms, conservation categories and applications are presented. in groups of conditions, intraditional medicine. The medicinal flora of the RC includes 1115 species from 141 families, with a predominance of Asteraceae, Fabaceae, Lamiaceae and Solanaceae. The majority are herbaceous, native and wild, less than 20% cultivated and distributed mainly in the mesotropics. Ninety-one medicinal species endemic to Peru and 10 endemics exclusive to the RC were found. 59 species were registered within some category of threat and 18 in critical danger, according to national legislation. They have applications in 21 groups of conditions, with digestive and respiratory predominance. This compendium constitutes the baseline for monitoring medicinal species, in relation to conservation and climate change.

Revealing How Human Activity and Native Plants Outshine Climate in Shaping New Invasive Alien Plant Elevational Patterns in Nature Reserves

ABSTRACTAimWe aim to investigate whether invasive alien plants introduced at different times exhibit variations in elevational distribution patterns and to explore the correlations of these patterns with climate, native plants and human activity.LocationGuangxi, China.MethodsWe recorded plant richness and cover across elevational gradients at 25–34 sites within each reserve, utilising 84–134 roadside plots per site. Using generalised linear mixed model (GLMM), we assessed the impacts of climate, native plants and human activity on the distributions of all, old and new invasive alien plants across the region and within the nature reserves.ResultsAt regional scales, the cover of all, new and old invasive alien plants decreased with increasing elevation, while only the richness of old invasive alien plants exhibited a similar pattern. Contrasting patterns were observed in Dayao Mountain, where the cover of old invasive alien plants decreased while the cover of new invasive alien plants increased. The richness patterns of all and new invasive alien plants were opposite between Dayao Mountain and Yachang Orchid. Moreover, native plant richness was negatively correlated with the richness of invasive alien plants, while interference intensity positively affected new invasive alien plants at both regional and reserve scales. At the regional scale, native plant richness accounted for 78.27%, 91.94% and 60.9% of all, old and new invasive alien plants respectively. Interference intensity accounted for 33.85% of the variation in new invasive alien plants. Annual mean temperature positively influenced the cover of all and old invasive alien plants at both regional and reserve scales, explaining 36.91% and 74.28% of their regional variation. Additionally, interference intensity and distance to human settlements positively impacted the cover of new invasive alien plants, contributing to 50.95% and 31.92% of their variation at regional scales.Main ConclusionThe distinct distribution patterns of old and new invasive alien plants highlight the significance of residence time in understanding their dynamics. Climate factors constrain the cover distribution of all and old invasive alien plants, whereas interference intensity and distance to settlements determine the distribution of new invasive alien plants. Notably, native plants play a vital role in preventing the establishment and spread of invasive alien plants within nature reserves, and their effectiveness increases with longer residence times. Our findings highlight the critical importance of minimising human interference and conserving native species for the effective management of invasive alien plants in nature reserves.

Cultivar-dependent differences in plant bud microbiome and functional gene pathways in woody plants commonly used in urban green space.

Plant richness and microbiota have been associated with plant health; hardly any studies have investigated how plant taxa differs in microbiota in the context of human health. We investigated the microbial differences in buds of 83 woody plant taxa used in urban green spaces in hemiboreal climate, using 16S rRNA and whole metagenome shotgun sequencing. Bud microbial community was the richest in Cotoneaster Nanshan and C. integerrimus, and Malus domestica cultivars 'Sandra' and 'Lobo' and poorest in Ribes glandulosum. Metagenomic shotgun sequencing of two M. domestica and four Ribes varieties confirmed differences in taxa in bud microbiota and indicated higher siderophore synthesis in Malus. Microbial richness, including bacteria, archaea and viruses, and functional richness of gene pathways was higher in Malus compared to Ribes. The ten most abundant amplicon sequence units, often referred as species, belonged to the phylum Proteobacteria. The differences between plant taxa were evident in classes Alpha- and Gammaproteobacteria, known for potential human health-benefits. Since environmental microbiota contributes to human microbiota and immunoregulation, horticultural cultivars hosting rich microbiota may have human health benefits. Further studies are needed to confirm the effectiveness of microbially-oriented plant selection in optimizing human microbiota and planetary health.

Exploring winter diet, gut microbiota and parasitism in caribou using multi-marker metabarcoding of fecal DNA.

In conservation strategies, getting precise and repeatable information on the species' diet and health without relying on invasive or laborious methods is challenging. Here, we developed an efficient and non-invasive workflow for the sequencing and analysis of four taxonomic markers from fecal DNA to characterize the gut microbiota, parasites, and plants and lichens composing the winter diet of caribou (Rangifer tarandus), Canada's most iconic endangered species. Sequencing of the 18S rRNA gene of eukaryotes from seven locations in Manitoba and Saskatchewan, Canada, allowed for the detection of five genera of parasites in caribou feces (including Nematodirella and Parelaphostrongylus) with variable frequency of occurrence depending on sampling location and sex. Our workflow also revealed a rich winter plant and lichen diet in caribou, with respectively 29 and 18 genera identified across all samples through plant and fungal ITS2 sequencing. Relationships between the gut microbiota and both the diet and parasite richness were also identified. Of note, the Central Saskatchewan sampling location was characterized by a clearly distinct gut microbiota which could be linked to an epiphytic lichen-rich diet. Overall, our results showed the potential of this multi-marker DNA metabarcoding workflow as an efficient tool to provide insights into the species biology and ecology.

Tectonic and climatic controls on plant biodiversity in the Hengduan Mountains, China

Mountainous regions contain some of the most dynamic landscapes in the world and host a majority of the global biodiversity hotspots. The Hengduan Mountains, located at the syntax of Eurasia and India, have a complex geological history associated with the hyperdiverse assemblage of species. Tectonics and geomorphic and climate processes in the Hengduan Mountains may have jointly caused the emergence of high biodiversity. We propose three mechanisms that may promote high-level montane biodiversity: habitat creation, habitat disruption, and habitat oscillations. We mapped species richness patterns for seed plants and computed phylogenetic endemism across the entire Hengduan region. We developed a set of geomorphic metrics regarding these mechanisms to link plant richness and phylogenetic endemism patterns. By estimating the component of species richness due to habitat heterogeneity, we isolate the component due to tectono-geomorphic processes. We found that regions of exceptionally high species richness are explained by a combination of habitat heterogeneity and tectono-geomorphic processes, while glaciation and high climate change velocity are associated with low richness, thus contributing to recent extinction. We interpret the richness of biodiversity hotspots in the Hengduan Mountains in terms of climatic and tectonic processes.

Predicting Potential Distribution of Teinopalpus aureus Integrated Multiple Factors and Its Threatened Status Assessment

The accurate prediction of the niche and the potential distribution of a species is a fundamental and key content for biodiversity related research in ecology and biogeography, especially for protected species. Biotic interactions have a significant impact on species distribution but are often overlooked by SDMs. Therefore, it is crucial to incorporate biotic interaction factors into SDMs to improve their predictive performance. The Teinopalpus aureus Mell, 1923 is endemic to high altitudes in southern East Asia, renowned for its exceptional beauty and rarity. Despite the significant conservation value, its spatial distribution remains unclear. This study integrated climate data, host plants, and empirical expert maps to predict its potential distribution. The results indicated that utilizing the species richness of host plants as a surrogate for biotic interactions was a simple and effective way to significantly improve the predictive performance of the SDMs. The current suitable distribution of T. aureus and its host plants is highly fragmented, primarily concentrated in the Nanling and Wuyi Mountains, and consisting of numerous isolated small populations. Given climate change, their distribution is significantly shrinking, increasing the threatened level in the future. Especially for the population of T. aureus hainani Lee, the likelihood of extinction is extremely high. Abiotic factors not only directly affect the distribution of T. aureus but also indirectly impact it through the host plants. This was evident in the delayed response of T. aureus to climate change compared to its host plants, which is called the “hysteresis effect” caused by biotic interactions. Overall, we tentatively suggest regarding T. aureus as a vulnerable species. In the future, multiple measures could be taken to indirectly protect the feeding and habitat resources of T. aureus by conserving host plants, thereby enhancing its survival prospects.

Nutrients, isolation and lack of grazing limit plant diversity in restored wetlands

Abstract Agricultural intensification has led to the loss of most natural wetlands from human‐dominated landscapes but, in recent decades, wetland restoration has gained traction worldwide. Restoration of suitable habitat conditions is hampered by nutrient residues from decades of high‐input farming, by continued input of nutrients from surrounding farmland and by incomplete restoration of natural hydrology. We assessed the effect of wetland restoration and disturbance (grazing) on vascular plant and bryophyte diversity in restored wetlands in Denmark at plot and landscape scales. Compared to near‐natural wetlands, we found a lower species richness and community uniqueness in restored wetlands, but we also found that grazing had a positive effect on vascular plant richness in restored wetlands. The size of the local species pool, presence of near‐natural habitat prior to restoration and near‐natural restored hydrology all had positive effects on plant diversity, whereas high soil iron and nitrogen had negative effects. Synthesis and applications: Restoration of plant diversity in wetlands is challenging, but our results point to potential remedies: plan restoration areas near colonisation sources of the target biota, restore hydrology to near‐natural conditions, discontinue nutrient loads from surrounding arable land and restore near‐natural grazing regimes. Bryophytes may be particularly useful as indicators for successful restoration of wetlands.

Native Gramineae outperform Leguminosae in enhancing ecosystem multifunctionality during semiarid desert steppe restoration

The effects of reseeded native Gramineae and Leguminosae species on the multifunctionality of desert steppe have remained unclear. Therefore, we examined a semiarid desert steppe that was reseeded 5 years earlier with a dominant native Gramineae species, Agropyron mongolicum; a dominant native Leguminosae species, Lespedeza potaninii; and a 1:1 reseeded mixture of A. mongolicum × L. potaninii. We evaluated the changes in plant communities and soil properties and then quantified aboveground ecosystem multifunctionality (AEMF), belowground ecosystem multifunctionality (BEMF), and overall ecosystem multifunctionality (EMF) using an averaging approach. Compared with the native steppe without reseeding, both reseeded A. mongolicum and A. mongolicum × L. potaninii increased fine root volume, plant height, plant cover, aboveground biomass (AGB), belowground biomass (BGB), soil water storage (SWS), soil organic carbon, light fraction organic carbon, labile organic carbon, total nitrogen (TN), nitrate nitrogen, and total phosphorus (P), but decreased soil bulk density. However, reseeded L. potaninii increased coarse root volume, plant height, plant cover, AGB, BGB, and SWS but decreased plant richness, plant diversity, TN, and total P. In addition, reseeded A. mongolicum and A. mongolicum × L. potaninii increased AEMF, BEMF, and overall EMF, but reseeded L. potaninii only increased AEMF. Further analysis indicated that the fine roots played a crucial role in improving individual ecosystem functions and eventually in determining EMF. Therefore, the reseeding of a desert steppe with Gramineae species has greater potential than with Leguminosae species for improving EMF, since Gramineae species have greater fine roots volume than Leguminosae species.

Exploring the potential of bioactive compounds of Capparis spinosa L. from Morocco: Unveiling its antioxidant and antifungal powers against Alternaria alternata

Capparis spinosa L. is a Mediterranean shrub and one of the most important species of the gender Capparis due to its ecological, medicinal and economic importance. This species has strong adaptation characteristics to regions with fluctuating climates. This work aims to evaluate the effect of the locality’s climate and plant’s parts on the content of polyphenols, flavonoids and antioxidant and antifungal activities of caper leaves and seeds. The present study was carried out in 7 localities in 2 Moroccan regions, Oriental and Fez-Meknes, where we collected leaves and seeds samples. Phenolic compounds were determined by the Folin Ciocalteu method, antioxidant activity was studied by DPPH and ABTS tests and an in vitro test of antifungal activity was achieved using Alternaria alternata. The analysis of variance showed no significant effect of locality, plant’s parts and their interaction on the phenolic compounds, antioxidant and antifungal activities of C. spinosa. Methanolic leaves extracts demonstrated the most favorable outcomes, yielding a maximum polyphenol content of 124.48 ± 0.05 mg EAG/g DW. Additionally, the maximum flavonoid content was recorded at 24.51 ± 0.01 mg EQ/g DW. The evaluation of the antioxidant activity showed that the minimum inhibitory concentration at 50 % (IC50) is 2.06 ± 0.05 mg/mL and 2.05 ± 0.02 mg/mL using DPPH and ABTS tests respectively. These extracts exhibited the highest % of inhibition, 30.59 % at 1000 ppm against A. alternata. The richness of the caper plant in bioactive compounds reveals an interest in its therapeutic and pharmaceutical virtues. In addition, it could be an alternative to chemicals for the control of phytopathogenic fungi on fruits or vegetables.

Reseeding increased plant biomass production and soil fertility, but not plant species diversity in degraded grasslands in China

Reseeding is a primary measure to restore degraded grasslands. Numerous studies have conducted experiments to investigate how the properties of grassland ecosystems respond to reseeding in China. However, there is a lack of summary of the results of these studies. Here, we conducted a hierarchical random-effects meta-analysis on the effects of reseeding on plant, soil, and microbial properties. We collected 19 variables, including plant biomass, species diversity and richness, soil organic carbon content, soil total and available nutrients, soil water content, soil microbial biomass and diversity, and enzyme activity, from a dataset of 1363 paired observations (degraded vs. reseeded) from 75 publications. The results showed that reseeding increased aboveground and belowground plant biomass by 70.2% and 68.0% on average, respectively. Reseeding increased soil organic carbon, phosphorus, and potassium contents, but did not affect soil nitrogen levels. Reseeding increased soil microbial nitrogen under conditions of tillage and fertilization. Reseeding age was found to have a positive correlation with species richness, while planting type, fertilization, and tillage did not have a significant impact on the species richness and diversity. Under the treatments of fertilization, non-tillage, and mix-planting, the response ratio of aboveground biomass to reseeding was positively correlated with the response ratio of species diversity to reseeding. Our results concluded that current reseeding practices can significantly improve plant biomass production and soil fertility but have minor effects on plant species diversity. These findings indicate that the preservation of biodiversity should receive greater attention from both researchers and practitioners in grassland remediation in China.

Non-native palm affects arthropod communities and litter decomposition in an ongoing biome shift

The emergence of novel ecosystems, characterized by shifts in species composition and interactions, abiotic conditions and altered ecosystem functioning, is a major and inevitable challenge to contemporary ecosystem management. This study examines the ecological implications of Trachycarpus fortunei, a non-native evergreen palm, currently involved in a biome shift from deciduous temperate forest to evergreen laurophyllous forest in the Southern European Alps. Specifically, we investigated the effects of T. fortunei encroachment in peri-urban forests on flying and ground-dwelling arthropod communities as well as on leaf-litter decomposition. We found that the presence of T. fortunei altered arthropod community composition, mostly by reducing the number of herbivore species. This effect was likely driven by the lower quality of palm leaves as a food source compared to deciduous, dicotyledonous tree leaves and by a lower plant richness in the herb and shrub layer. Furthermore, we observed higher rates of leaf-litter decomposition associated with increasing abundance of young palm trees, which was not explained by predictors commonly associated with litter decomposition (i.e., detritivore abundance, litter depth and air temperature). Hence, the slow decay of palm leaves appears to be counterbalanced by the favourable conditions for litter decomposition within dense palm stands. Overall, our findings indicate that high densities of the non-native palm species (T. fortunei) impacts herbivore arthropod communities in the Southern European Alps, providing first evidence of possible effects on ecosystem functioning of this ongoing biome shift. These outcomes are integral components of the broader process of laurophyllisation in the study region, a phenomenon linked to climate warming and land use change, encompassing both native and non-native species.

Modeling the Effect of Greenways’ Multilevel Visual Characteristics on Thermal Perception in Summer Based on Bayesian Network and Computer Vision

The aim of this study is to reveal the effects of multilevel visual characteristics of greenways on thermal perception in hot and humid regions during summer and to explore the potential of visual design to enhance psychological thermal comfort. Data on light (L), color (C), plant richness (PR), space openness (SO), scenic view (SV), thermal sensation (TS), and thermal preference (TP) were collected through questionnaires (n = 546). Computer vision technology was applied to measure the green view index (GVI), sky view index (SVI), paving index (PI), spatial enclosure (SE), and water index (WI). Using the hill climbing algorithm in R to construct a Bayesian network, model validation results indicated prediction accuracies of 0.799 for TS and 0.838 for TP. The results showed that: (1) SE, WI, and SV significantly positively influence TS, while L significantly negatively influences TS (R2 = 0.6805, p-value < 0.05); (2) WI, TS, and SV significantly positively influence TP (R2 = 0.759, p-value < 0.05).

Predicting the habitat suitability and species richness of plants of Great Himalayan National Park under different climate change scenarios.

This study elucidates the distribution of plants in Great Himalayan National Park (GHNP), India, in current and different future climate change scenarios. The distribution of plants and habitat suitability in GHNP due to climate change was analyzed by MaxEnt, species distribution model (SDM) algorithm. In this study, species presence records were retrieved through field survey and published literature. We have projected the distribution of 44 plant species using MaxEnt and tested whether GHNP is performing well in conserving the plant species. Initially, we have constructed a model for each species and created the habitat suitability map from average of ascii files and later we added the maps of all species in order to make binary map to show the species richness in the selected climate scenarios. The model was created using the HADGEM-2 global circulation model in 2050 and 2070years by using climate change situations of RCP 2.6 and RCP 8.5. The area under curve (AUC) values in the final models of 44 plant species were in the range 0.70-0.97 that indicates statistically significant results. The model identified precipitation of driest month followed by altitude and annual mean temperature as most determining variables in the distribution of plants of GHNP in selected climate scenarios. In the present study, we found that overall suitable habitat increased for nine species, decreased for thirty-four, and unchanged for one plant species in terms of percent area change from current to future scenarios. So these nine species were found to be more adaptable towards changing climate than the other plant species in this study. The species richness was high in western and southwestern parts of GHNP in the current scenario, however under future climatic scenarios, species richness shows a decreasing trend. Based on our findings, it can be concluded that GHNP should be prioritized for conserving the plant species.

Discreet but diverse and specific: Determining plant‐herbivore interactions across a species‐rich plant family in a tropical rain forest

AbstractStudying plant–herbivore interactions within tropical rain forests is fundamental to understanding their ecology and evolution. An important aspect of plant–herbivore dynamics is the role of temporal and taxonomic variables in determining associations between herbivores and their host. Using the diverse and chemically rich plant family Annonaceae (Magnoliales), we conducted a year‐long study in Ecuador's Yasuní National Park in lowland Amazonia. We focused on nine understory tree species across a broad phylogenetic range within Annonaceae. For these species, we investigated patterns of herbivory, identified herbivores through DNA barcoding, and documented unique ant–butterfly associations. In general, leaf damage ranged from 0.09% to 25%, with significant temporal fluctuations for three species. Notably, Anaxagorea brevipes and Unonopsis veneficiorum faced higher herbivore pressure when compared to the other studied species. We document a discreet but diverse herbivore community, with 40 larvae from 12 Lepidoptera families collected throughout the year. Our findings identify, for the first time across a phylogenetically diverse sampling of Annonaceae, the specialization of herbivores on our focal species. Overall, our data provide valuable information on herbivory patterns at the local scale for this important rain forest plant family. Furthermore, these findings contribute to our understanding of the ecological processes that influence plant species diversity in tropical rain forests.Abstract in Spanish is available with online material.

Interplay between native plant performance and environment shapes resistance to aquatic plant invasion

Abstract In the limited number of studies on biotic resistance in freshwater ecosystems, experimental studies have supported that native plants play a role in resisting exotic plant invasion, but field observations have often reported positive relationships between exotic and native plant richness. To determine the reasons for the lack of evidence supporting biotic resistance in field observations, we surveyed the richness, biomass and coverage of exotic and native aquatic plants in 2801 quadrats at 287 sites in various freshwater ecosystems of China and examined the impacts of scale and environmental factors on the relationships between native and exotic plant richness and performance. At both the site and quadrat scales, we observed a positive correlation between the richness of exotic and native plants. However, at the quadrat scale, high native plant richness was associated with a reduction in the biomass of exotic emergent and floating plants as well as the biomass of exotic submerged plants in low‐nutrient water bodies. An increase in native plant performance, a metric that integrates the biomass and coverage of native plants, was associated with a decrease in both the richness and biomass of exotic plants at both scales. Furthermore, with increasing native plant performance at the quadrat scale, the richness of exotic plants declined more strongly in low‐nutrient water bodies than in high‐nutrient water bodies, and the decline in the biomass of exotic emergent and floating plants was more severe in shallow water than in deep water. Synthesis. Our results indicate that native plant performance is more important than richness for resistance to invasion in freshwater ecosystems, and the strength of biotic resistance is related to environmental factors. This study highlights the importance of environmental variables and multiple native community features and invasibility metrics in field observational studies of invasion.

Spatial, environmental and functional distances among temporal ponds attenuate synchronization, stabilizing plant richness and biomass dynamics

Synchronized dynamics reduces ecosystem stability, as local variations in biomass or richness are directly propagated to variations in metacommunity dynamics. Synchronization of biodiversity dynamics can occur due to dispersal among communities and similar responses of different communities to correlated environmental variations, the Moran effect. This congruent response of different communities to environmental dynamics depends on their similar functional composition, which is determined by the similarity in local conditions and the spatial distance between them. In a metacommunity of 51 temporary ponds that were surveyed for 14 years, we evaluated the existence of synchronized dynamics in plant richness and biomass among communities, and their association with temporal stability. A wide range of dynamics was observed, from asynchronous to synchronous rhythms. Path analysis based on Mantel tests supported the decoupling of richness dynamics by the geographic, environmental, and functional distances between pairs of communities. Only the functional distance between communities weakly affected biomass synchrony. Synchrony in both richness and biomass between communities reduced the stability of the biomass dynamic. While synchrony in richness reduced its stability, synchrony in biomass enhanced the stability in richness dynamic. The role of rare species in richness dynamics and of dominant species in biomass dynamics may explain the observed discrepancies. Consequently, the size of metacommunities (the spatial extent and number of local communities), spatial heterogeneity, and functional diversity promote ecosystem stabilization by the mechanisms evidenced here. Climate change, environmental homogenization and landscape fragmentation may drive the synchronization and destabilization of biodiversity dynamics.

Agricultural legacy shapes plant diversity patterns in mountain grasslands of Maramureș and Bukovina: A cross‐border perspective (Ukraine, Romania)

Abstract We investigated farming practices and grassland plant diversity patterns in the historical regions of Maramureș and Bukovina, located in the central Eastern Carpathians of Romania and Ukraine. We explored the influence of social and historical factors on recent grassland plant diversity, including changes and modifications in land use and grassland management practices. We used stratified random sampling to select 48 grassland parcels in eight villages on the Ukrainian‐Romanian borderlands. We identified the factors that affect the composition and diversity of grassland vascular plants and bryophytes at multiple spatial scales and compared the frequency and timing of historical and recent grassland management practices to distinguish between preserved and modified agricultural traditions. In most of the grassland parcels studied (83% in Romania and 78% in Ukraine), traditional land use persisted. Local plant species richness was primarily influenced by management practices, outweighing the impact of topography and soil factors. Regular mowing at appropriate intensity increased the richness of vascular plants, while grazing promoted the richness of bryophyte species. Modifications to farming systems, observed in all studied villages, were mainly due to declining population and livestock numbers. Although the timing of spring and autumn grazing in hay meadows still adhered to tradition, mowing schedules shifted earlier, especially for the first cut of two‐cut hay meadows. Traditional corralling, fertilization and hayseed application have become rare or discontinued in certain villages, while controlled burning has increased. Past use of mineral fertilizers in Ukrainian villages during the Soviet era influenced the recent diversity and composition of vascular plant species, favouring nutrient‐demanding species. Social factors and agricultural policies indirectly affect biodiversity in semi‐natural grasslands, leaving a tangible footprint even in the most remote areas of the Carpathian Mountains. We provide basic recommendations to preserve the remarkable biodiversity of the region. Read the free Plain Language Summary for this article on the Journal blog.

The role of fossils for reconstructing the evolution of plant development.

Many of the developmental innovations that underpin the diversity of plant form alive today, such as those facilitating apical growth, branching, leaves, roots, wood and seeds, all evolved over 360 million years ago. Fossils, as our only direct record of plant form in the past, are thus essential for interpreting the origin and evolution of these innovations. The focus of this Spotlight is to showcase the rich plant fossil record open for developmental interpretation and to cement the role that fossils play at a time when increases in genome sequencing and new model species make tackling major questions in the area of plant evolution and development tractable for the first time.

Association Between Dietary Patterns and Subgingival Microbiota: Results From the Oral Infections, Glucose Intolerance, and Insulin Resistance Study (ORIGINS).

To study the association between dietary patterns and subgingival microbiota. Participants (n = 651) who were enrolled in the Oral Infections, Glucose Intolerance, and Insulin Resistance Study (ORIGINS) with subgingival plaque sampling (n = 890 plaques) and a dietary assessment were included. 16S rRNA gene amplicon sequences of subgingival plaque from sites with either probing depth <4 or ≥4 mm were processed separately and used to obtain α-diversity metrics (Faith, Shannon, Simpson, Observed) and taxa ratios (Red Complex to Corynebacterium [RCLR], Treponema to Corynebacterium [TCLR], and Treponema to Neisseria [TNLR]). Food frequency questionnaires (FFQs) were processed to calculate Alternate Healthy Eating Index (AHEI) and A Priori Diet Quality Score (APDQS) scores. Mixed regression models examined the mean levels of microbial metrics across quartiles of diet quality. Means ± standard errors are reported along with p-values. In multivariable models assessing the association between diet scores and α-diversity metrics, higher AHEI values were significantly associated with lower Faith (p-value = 0.01) and Observed (p-value = 0.04) diversity values; similar findings were observed for APDQS (p-value = 0.01, p-value = 0.04). In multivariable models assessing the association between diet scores (AHEI and APDQS) and taxa ratios (RCLR, TCLR and TNLR), as the AHEI quartile increased, all taxa ratios decreased significantly as follows: -1.06 ± 0.093 in Q1 to -1.34 ± 0.099 in Q4 (RCLR), -0.43 ± 0.077 in Q1 to -0.64 ± 0.083 in Q4 (TCLR) and -0.09 ± 0.083 in Q1 to -0.38 ± 0.089 in Q4 (TNLR), respectively. In contrast, as the APDQS quartiles increased, only TNLR decreased significantly from -0.08 ± 0.085 in Q1 to -0.34 ± 0.091 in Q4. Diets rich in fruits, vegetables, whole grains and other nutritionally rich plant foods are associated with lower oral microbial diversity and favourable ratios of pathogenic to commensal microbiota.

The microclimatic effects of the native shrub Ephedra californica (Mormon tea) in California drylands.

The impacts of climate change can be profound in many ecosystems worldwide, including drylands such as arid and semi-arid scrublands and grasslands. Foundation plants such as shrubs can provide microclimatic refuges for a variety of taxa. These shrubs can directly influence micro6 environmental measures, and indirectly increase the local environmental heterogeneity as a result. We examined the hypothesis that, in comparison to an open gap, foundation shrubs improve the microclimate beneath their canopy and that microclimate is in turn a significant predictor of annual vegetation. The following predictions were made: 1) mean air temperature (NSAT), ground temperature (SGT), and vapour pressure deficit (VPD) will be significantly lower under the shrubs than in the open microsites; 2) shrub canopy size predicts microclimate; 3) site-level aridity estimates and percent shrub cover influence annual plant abundance and richness; and 4) the site13 level mean of NSAT and VPD predict annual plant abundance and richness. Our study took place in Southwestern California, U.S.A. We used a handheld device with a probe to measure microclimatic variables such as near-surface air temperature (NSAT), near-surface relative humidity (NSRH), and surface ground temperature (SGT) at the shrub species Ephedra californica and in the open gap, across six sites in California, United States. Air temperature and RH were then used to calculate VPD. The mean number of vascular plant species across each site was also recorded. Only SGT was significantly reduced under shrub canopies. Canopy volume was not a significant predictor of all three microclimatic variables, demonstrating that even small, low-stature shrubs can have facilitative effects. Furthermore, total shrub cover and aridity at sites significantly predicted mean plant richness and abundance. There were significantly more plants associated with shrubs and there were significantly more species associated with the open. Mean air temperature and VPD at the site-level significantly predicted vegetation abundance and richness, though microsite-level differences were only significant for richness. Foundation shrubs are a focal point of resiliency in dryland ecosystems. Understanding their impact on microclimate can inform us of better management, conservation, and restoration frameworks.