Non-metric Multidimensional Scaling Ordination Research Articles

Ant's Nest as a microenvironment: Distinct Mucoromycota (Fungi) community of the red wood ants' (Formica polyctena) mounds.

Many social insect species build nests, which differ from the surrounding environment and are often occupied by specific organismal communities. These organisms may interact mutualistically or parasitically with the nest-builders, or simply co-occur, being able to survive in these microenvironments. In temperate forests, red wood ants (e.g. Formica polyctena) are known to create distinct, highly developed nests, which consist of large, above-ground mounds, built primarily out of plant matter collected from the forest litter. The microorganismal communities of such mounds remain understudied. As representatives of Mucoromycota fungi commonly engage in the decomposition process of the forest litter, they would be expected to occur in the mounds. However, it is still not known whether the Mucoromycota community of these ants' nests differ from the one of the surrounding forest litter. In order to distinguish mound-associated taxa, we characterized Mucoromycota communities of Formica polyctena mounds and the surrounding forest litter. We sampled four sites, twice in a season. Sampled material was plated on agar media and emerging Mucoromycota colonies were identified based on their morphology. Fungal identification was further confirmed using DNA barcoding. In order to compare described communities, PERMANOVA test and non-metric multidimensional scaling ordinations were used. To distinguish taxa associated with the mounds, multilevel pattern analysis was performed. Our results show that the Mucoromycota community of Formica polyctena's mound differs from the community of the surrounding forest litter. While representatives of Entomortierella lignicola and Absidia cylindrospora clade were found to be associated with the mound environment, representatives of Umbelopsis curvata and Podila verticillata-humilis clade were associated with forest litter, and were rarely present in the mounds. Our findings strongly suggest that the red wood ants' nest is a specific microenvironment in the temperate forest floor, which is a preferred microhabitat for the mound-associated Mucoromycota, possibly adapted to live in proximity to ants.

Response of understory vegetation to long-term occupancy by introduced Pinus species in temperate deciduous hardwood forests

In many temperate regions of the world, conifer species have been planted to stabilize soils and promote site recovery on former hardwood sites that were cleared for agriculture. In many areas of eastern North America, these conifer plantings consisted of introduced (non-native) Pinus species planted on abandoned agricultural land once dominated by mesophytic hardwood species. These plantings constitute a shift in overstory composition away from native hardwood species with nutrient-rich litter that decomposes more quickly towards Pinus species with recalcitrant litter that may alter soil chemistry and nutrient availability. To examine how edaphic conditions associated with long-term introduced Pinus species occupancy are related to forest regeneration and herbaceous-layer diversity and composition, we sampled a total of 97 plots in planted Pinus echinata and Pinus strobus stands and naturally regenerated hardwood stands growing on two ecological landtype phases (ELTPs) of southern Indiana, USA forests, Fagus-Acer saccharum/Arisaema Mesic Ridges, and Acer saccharinum/Boehmeria Bottomlands. We collected vegetation data and analyzed soil samples to examine herbaceous-layer species distribution across gradients using non-metric multidimensional scaling (NMS) ordination. Two-way ANOVA was used to examine differences in individual species and species functional groups across stand types (P. echinata, P. strobus, and native hardwoods) and ELTPs. Our results show that differences in soil chemistry resulting from Pinus spp. occupancy were associated with differences in the composition and distribution of herbaceous-layer species in ordination space. Species across stand types and ELTPs were distributed across dominant gradients related to litter depth, cation exchange capacity, cation content, and soil aluminum concentration. Hardwood sites had significantly greater herbaceous-layer cover (139.6 ± 8.0 %) than P. echinata (48.5 ± 6.2 %) or P. strobus sites (81.7 ± 7.7 %), as well as greater herbaceous-layer species richness and diversity (mean species richness was 46.9 ± 2.1 on hardwood stands vs. 33.3 ± 1.6 and 36.4 ± 2.0 on P. echinata and P. strobus stands, respectively). Pinus echinata stands contained a greater density of woody regeneration, including Quercus spp. (201 ± 48 saplings ha−1) and Fagus grandifolia stems (415 ± 82 saplings ha−1), both of which occurred in greater density than Acer saccharum (163 ± 93 saplings ha−1) and A. rubrum (70 ± 64 saplings ha−1). Our results suggest that pine occupancy has created divergent successional trajectories in comparison to hardwood stands. These differing trajectories may offer both challenges and opportunities for restoration efforts. For example, the greater abundance of Quercus reproduction under P. echinata on ridges, combined with less productive soils, may allow Quercus stems to be promoted into the canopy with less competition from mesophytic competitors.

Karst landforms as microrefugia for soil Collembola: Open versus forested dolines

Enclosed surficial karst dolines are geomorphologically diverse habitats with the potential to strongly shape community structure and the distribution of functional groups of organisms. Forest habitats in karst landscapes are characterized by lower soil temperatures and microclimatic fluctuations compared to open habitats; therefore, they may provide favorable conditions for cold-adapted/psychrophilic species, which are highly vulnerable to climate warming. We compared the diversity and structure of soil Collembola communities at sites along microclimatic gradients in open and forested karst dolines. The effect of topography and related environmental conditions on the distribution of ecological groups of soil Collembola was analyzed, and the function of the dolines as potential climate refugia for psychrophilic arthropods was assessed. The karst dolines revealed significant habitat heterogeneity, including warm plateaus and S-facing slopes and colder and wetter bottoms and N-facing slopes. The inner sites of the dolines had an overall higher abundance and species richness compared to the plateau sites. Nonmetric multidimensional scaling ordination revealed a clear delimitation of Collembola communities in terms of warmer and cooler sites in the open dolines, while the forested dolines did not reveal such a clear pattern. The studied dolines showed a potential to serve as microrefugia in the context of global climate change. Dolines could support the long-term persistence of at least some species such as cold-adapted species. Karst dolines in the temperate zone play a key role in maintaining biodiversity; therefore, they should be central in biodiversity conservation programs.

Environmental heterogeneity influences liana community differentiation across a Neotropical rainforest landscape.

We examined the variation in liana community composition and structure across geopedological land units to test the hypothesis that environmental heterogeneity is a driving force in liana community assembly. The study site was the Los Tuxtlas Tropical Biology Station, SE Mexico, a reserve that encompasses 640 ha of tropical rainforest. We sampled all lianas with basal diameter ≥1 cm in three 0.5-ha plots established in each of five land units (totaling 15 plots and 7.5 ha). We censused 6055 individuals and 110 species. Overall, the most speciose families were also the most abundant ones. Density and basal area of some dominant liana species differed among land units, and a permutational multivariate analysis of variance (PERMANOVA) and a non-metric multidimensional scaling ordination (NMDS) revealed differences in the presence, density, and basal area of liana species across the landscape. Liana composition and structure were highly heterogeneous among land units, suggesting that variations in soil water availability and relief are key drivers of liana community spatial differentiation. By showing that soil and topography play an important role at the landscape scale, we underscore the ecological relevance of environmental heterogeneity for liana community assembly. In the future, as our ability to assess the local environmental complexity increases, we will gain a better understanding of the liana community assembly process and their heterogeneous distribution in tropical forests.

Changes in grassland vegetation on the island of Plavnik (Croatia) over 100 years

The changes in the grassland vegetation that have occurred over the last almost 100 years on the northeastern Adriatic island of Plavnik (Croatia) were studied. For this purpose, 29 phytosociological relevés of standard plot size were collected using the Braun-Blanquet phytosociological approach and compared with those of 100 years ago. With the aim of defining the differences among the communities and identifying the main environmental gradients, cluster analysis (Ward's method on a Chord distance matrix) and non-metric multidimensional scaling ordination were applied. Taxa score-weighted means of the Ellenberg-type indicator values of main environmental variables were used to assess ecological differences among communities, and disturbance-related indicator values were calculated to assess the disturbance regime in shaping plant communities. According to the syntaxonomic framework for the grassland associations, three associations and two subassociations were found. Among them the Festuco valesiacae-Poetum bulbosae (Poetalia bulbosae, Poetea bulbosae), the Helichrysetum italici salvietosum officinalis (Scorzoneretalia villosae, Festuco-Brometea), and the Hedypnoido rhagadioloidis-Asphodeletum ramosi were proposed as new. The Festuco valesiacae-Poetum bulbosae documents for the first time, based on phytosociological data, the occurrence of the Poetea bulbosae in Croatia. Three associations were considered extinct, possibly as a result of changes in grazing pressure and type.

Soil contamination around porphyry copper mines: an example from a semi-arid climate.

Extraction and processing of disseminated metalliferous ores, porphyry copper in particular, results in significant tonnages of waste and can cause severe disturbances and contamination in natural ecosystems. This is particularly important in semi-arid climates where natural soils are often deprived of organic matter and nutrients. This study was conducted on seven sites around Sungun Copper Mine, northwest Iran. Soil texture, EC, pH, and concentrations of nutrients, organic matter, along with 16 metal and metalloids were measured in 94 soil samples. Results showed a gradient of contamination from low contamination in natural hillsides to high contamination in mine waste depositories, Waste Dump and Oxide Dump, alongside Pakhir and Sungun Rivers. Nutrient deficiency occurred in disturbed sites. The main contaminant point sources were Waste Dump, mine pit drainage, and Oxide Dump. The results of Non-metric multidimensional scaling ordination showed elevated Cd, Zn, Fe, Cu, Pb, As, Mo, Mn, Co, S concentrations, high EC, and higher sand percentage in the sites affected by mine waste and acid mine drainage. Geo-Accumulation and Potential Ecological Risk Indices indicated that Pakhir riverside, Sungun riverside, and Oxide Dump have severe to moderate levels of environmental risks. Positive correlations between certain metal elements suggest common sources and similar reaction pathways, which may contribute to their similar geochemical behaviour in transport, deposition, and interdependence. Overall, the deficiency of organic matter and nutrients along with the soil sandy texture in contaminated sites of Sungun Copper Mine are the main limiting factors in managing metal mobility and soil remediation.

Phytosociology and ecological framework of forest tree species in the Toormang Valley, Dir Lower, Hindu Kush Range, Pakistan.

The phytosociological survey was conducted during 2018-2020. The research area was classified into five ecological zones based on habitat, physiognomy and species composition. Pc-Ord software was used for cluster analysis and four vegetation communities were established. The Quercus baloot-Quercus incana community is situated in Sair at an altitude of 1196 (mean ± SE) m altitude with a 14.1 ± 0 slope angle and contains eleven tree species. The Pinus wallichiana- Ailanthus altissima community had a relatively small number of tree species reported in Shakawlie at 1556 (mean ± SE) with a 17.5 ± 0 slope angle. The Pinus wallichiana- Quercus incana community is distributed in Wali Kandao and Mangi Kandao at altitudes of 2030.5 (mean ± SE) m and the slope angle was 19.2 ± 1.4. This community possesses a total of twenty-one tree species and is highly diverse. Similarly, the Populus alba - Platanus orientalis group was present in Banr Pate, with an altitude of 1613 (mean ± SE) m and a 16.3 slope angle. The principal component analysis (PCA) and non-metric multidimensional scaling (NMS) ordination methods were applied to study the relationships between ecological and soil variables with trees species. The NMS ordination of axis 1 was significantly correlated with Sand% (p<0.2), Nitrogen% (p<0.1) and Pb (mg/kg) (r= 0.876751, p<0.05), while the ordination of axis 2 was significantly correlated with Silt% (p<0.2), Sand% (p<0.2), Organic matter% (p<0.2), K (mg/kg) (r=0.882433, p<0.02), Fe (mg/kg)(r=0.614833, p<0.2), Ca (mg/kg) (r=0.721712, p< 0.2) and Zn (mg/kg) (r=0.609545, p<0.2). Similarly, the PCA ordination of axis 1 revealed that it was significantly correlated with phosphorus, calcium and slope angle, while that of axis 2 was significantly correlated with altitude, zinc and manganese.

Pan-Canadian review of community-based monitoring projects and their capacity to enhance environmental monitoring programs for cumulative effects assessments

While community-based monitoring (CBM) can support meaningful participation of the public in environmental decision-making, it remains unclear if and how CBM can support western science approaches to biophysical studies within cumulative effects assessment (CEA). We scored 40 Canadian CBM projects on their ability to enhance CEA's western science approaches to environmental monitoring. We used multivariate analyses to determine if the highest-scoring projects shared characteristics that could inform the design of CBMs to support CEA. Cluster analysis and non-metric multi-dimensional scaling ordination revealed that highest-scoring projects were distinct from lower scoring projects, and the Similarity Percentages Routine identified characteristics that differentiated these projects. The highest-scoring projects involved non-profit organizations as bridging organizations that coordinated community participation and received funding and in-kind support from provincial/territorial government agencies. Participants in these projects collected measurements and samples using standardized protocols described in training manuals. Their data were publicly accessible in georeferenced databases and were used for baseline studies and resource management. There are existing CBM projects in Canada that thus appear well positioned to enhance western science approaches to CEA. Further study is required to identify how CBM projects can be designed to braid Indigenous and western science approaches to mutually enhance CEA methods.

Structure of Collembola Communities in the Urban Gradient of Rīga City

Abstract The world’s increasing urbanisation and the deterioration of human quality of life in major cities have redirected the focus of urban planning toward green infrastructure improvement and, as a result, increased the research of urban ecosystems. This article analyses changes in the structure of Collembola communities in soil in the urban-rural gradient in the city of Rīga, Latvia. Soil samples were collected in 21 randomly selected sample plots within six urban habitats: street edge grasslands, downtown parks, private houses, cemetery grasslands, and urban and suburban forests. Soil samples were taken at the end of September/beginning of October 2017. A steel soil corer (D 50 mm, surface area 19.6 cm2, depth 10 cm) was used. In each plot, three soil samples were taken with a soil corer. Collembola were extracted from pooled samples from each habitat using a Berlese-Tullgren extractor. Nonmetric Multidimensional Scaling (NMS) ordination of Collembola data in sample plots yielded three statistically significant axes (p &lt; 0.01). The first axis explaining 49% of the data variation coincided with the urban-rural gradient. Species richness declined towards the city centre, while the Simpson’s Dominance Index increased. The species Mesaphorura macrochaeta predominates in the central habitats, while Parisotoma notabilis dominates in suburban forests.

Diversity and Phenology of Soybean Seed Fungal Endophyte Communities in the Upper Midwest United States

Infection over time by endophytic fungi in soybean seed and pods was documented in Iowa and Wisconsin in 2018. Three reproductive stages were sampled from six cultivars, with maturity groups (MG) ranging from 1.1 to 4.7, and included 216 blemish-free pods and 1,836 healthy seeds that were heavily disinfested to remove epiphytes. Thirty-five species and 11 genera were identified from 1,799 isolates using morphological and molecular evidence. Alternaria, Diaporthe, and Fusarium were dominant. The timing of endophyte infection was documented relative to MG. The lowest number of fungi were recovered from seed at R6, and infection sharply increased at R7. The abundance of Diaporthe and Fusarium isolates differed across MG and reproductive stage; shorter MGs had more Diaporthe isolates at earlier reproductive stages than longer MGs. Fusarium counts differed across MG but did not show consistent trends with seed maturity. Alternaria counts declined as seed matured but were not affected by MG. We used nonmetric multidimensional scaling to elucidate the phenology of seed infection within the endophyte community. This method helps represent the data in a lower dimension by measuring the similarity or dissimilarity between data points, making it a useful tool for grouping similar endophyte communities. The nonmetric multidimensional scaling ordination analysis of fungal taxa within endophyte communities revealed that the dominant genera in filled green pods were highly similar. However, this similarity was not observed among different stages of seed development, indicating that each taxon had distinct modes of infecting the seeds. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Impact of Phytophthora cinnamomi on the taxonomic and functional diversity of forest plants in a mediterranean‐type biodiversity hotspot

AbstractAimDiversity‐rich mediterranean‐type sclerophyllous forests are home to 20% of described species on Earth. In the Eucalyptus marginata (jarrah) forest of southwest of Western Australia diversity is being reduced by extensive human use and the introduction of the plant pathogen Phytophthora cinnamomi. This study investigated the influence of P. cinnamomi infestation on the structure, taxonomic and functional diversity, and species composition of the forest.LocationJarrah forest of southwestern Australia.MethodsSpecies abundance, understorey cover and canopy cover were assessed along 22, 30 m long transects which crossed infested and non‐infested zones in five reserves in the jarrah forest. A trait database was assembled for 137 plants using 13 traits related to nutrient and carbon acquisition, disturbance tolerance and reproduction. The responses of canopy cover, understorey cover, species richness, Shannon diversity, evenness, abundance, and functional diversity for trait groups, and all groups combined were modelled against reserve and zone as fixed effects and transect and transect section as random effects. To assess the species composition, non‐metric multidimensional scaling (NMDS) ordination based on Jaccard resemblance and indicator species analyses were used.ResultsSignificantly higher understorey cover, species richness, Shannon diversity and evenness were recorded in non‐infested compared to infested zones, but there were no changes in the canopy cover and overall abundance. In non‐infested zones, the functional diversity of nutrient acquisition and reproductive traits was higher, but the functional diversity of carbon acquisition traits was lower. No difference in functional diversity was recorded in disturbance tolerance and overall traits between the two zones. NMDS ordination and analysis of similarities (ANOSIM) revealed a significant difference in the species composition between the two zones, and 11 indicator species significantly associated with infested and non‐infested zones were identified.ConclusionPhytophthora cinnamomi has significantly affected the forest structure, taxonomic and functional diversity, and species composition. Contrasting responses of functional trait groups obscured overall trait responses to P. cinnamomi.

Active versus passive restoration of tallgrass prairie in the U.S. Midwest: plant species diversity and assemblage, net primary production and soil carbon sequestration

We investigated the plant species diversity, community assemblage, net primary production and soil carbon sequestration in an old field (OF), which went through passive restoration with spontaneous secondary succession, and a restored prairie (RP), which went through active restoration with reintroduction of native plants. The passive restoration in OF did not attain as high diversity and richness of plant species as did in RP. Our NMS (nonmetric multidimensional scaling) ordination revealed a clear divergence of RP and OF vegetation with dissimilar species compositions to separate paths of succession trajectory. The spontaneous succession in OF has made very little progress due to a potentially strong inhibitory priority effect of invasive plants. The belowground biomass in the high‐diversity RP was 1.3× higher than the low‐diversity OF. We found no measurable difference in soil C sequestration between RP and OF at this time, possibly due to edaphic factors, lack of legumes, or both. Human intervention is needed for restoring abandoned croplands—highly disturbed, fragmented and isolated habitats—to tallgrass prairies in the U.S. Midwest. Our recommended intervention includes but is not limited to removal of exotic plants, further augmentation of native plants (particularly legumes), and periodic burns.

Acidophilous grasslands in the Locarnese region (Southern Switzerland): description and classification of main plant communities

This paper presents a phytosociological study of dry and mesophilous meadows and pastures in the Locarnese region (Insubria - Southern Switzerland). Seventy-one vegetation relevés were analysed using both hierarchical classification and nonmetric multidimensional scaling (NMDS) ordination. Seven main clusters were identified and described as follows: (i) xerophytic grasslands on sandy soil dominated by Koeleria macrantha; (ii) mesophilous meadows with Arrhenatherum elatius and Centaurea transalpina; (iii) semi-dry meadows with Chrysopogon gryllus; (iv) semi-dry grasslands with Carex fritschii and Thalictrum minus; (v) nutrient-poor Phyteuma betonicifolium-Festuca nigrescens montane zone grasslands; Nardus stricta grasslands dominated by (vi) Festuca paniculata or (vii) Carex pilulifera. From a phytosociological point of view, a new association named Phyteumo betonicifolii-Festucetum nigrescentis, classified into the Nardo strictae-Agrostion tenuis alliance was proposed. In addition, we confirmed the presence of the Holco-Chrysopogonetum grylli association, within the Bromion erecti, which up to now was provisional only.

Responses of microbial communities in rhizocompartments of king grass to phytoremediation of cadmium-contaminated soil

King grass has been recognized as a potential phytoremediation plant species due to its high biomass and resistance to heavy metals (HMs). However, the possible impacts of cadmium (Cd) contamination on rhizocompartments' microbial activities in association with king grass have not been extensively explored. The utilization of 16S rRNA gene and ITS sequencing was carried out to examine alterations in the bacterial and fungal communities in the rhizosphere and rhizoplane of king grass in response to low and high Cd stress. Results demonstrated that both bacterial and fungal communities' diversity and richness were negatively impacted by Cd stress, regardless of its concentration. However, evenness did not exhibit any significant response to either of the concentrations. Additionally, nonmetric multidimensional scaling (NMDS) ordination demonstrated a significant difference (p < 0.001) in microbial communities under different treatments. The abundance of bacterial taxa such as Steroibacter, Nitrospira, Pseudoxanthomonas, Cellvirio, Phenylobacterium, Mycobacterium, Pirellula and Aquicella was adversely affected under Cd stress while Flavobacterium, Gemmata, Thiobacillus and Gemmatimonas showed no prominent response, indicating their resistance to Cd stress. Like that, certain fungal taxa for instance, Cladosporium, Cercophora, Acremonium, Mortierella, Aspergillus, Penicillium, Glomus and Sebacina were also highly reduced by low and high Cd stress. In contrast, Fusarium, Thanatephorus, Botrytis and Curvularia did not show any response to Cd stress. The identified taxa may have a crucial role in the growth of king grass under heavy metal contamination, making them promising candidates for developing bioinoculants to encourage plant performance and phytoremediation capability in HM-contaminated soils.

Non-native vascular flora of alpine areas in the White Mountains, New Hampshire, USA

ABSTRACT Arctic-alpine vegetation in the eastern United States is unique to northern New England and New York and is disjunct from similar areas in eastern Canada. We present the first study of the non-native flora in the region, specifically focusing on New Hampshire’s White Mountains. By combining literature and herbaria searches, field surveys, and a seventeen-year evaluation at an alpine hut in a hypothesis-driven framework, we document the composition, chronology, and persistence of non-native plant species establishments, regress richness in relation to elevation and disturbed area, and evaluate similarities to nineteen other alpine floras globally. Our results indicate that the White Mountains support one of the most species-rich non-native alpine floras known in the world, with 58 species detected at thirty-one sites since 1874, comprising 19 percent of 300 species documented in New Hampshire’s 22 km2 of alpine tundra. There is a negative relationship between non-native alpine plant richness and elevation along a mountain road on Mt. Washington. Moreover, elevation predicts richness per unit area in proximity to clusters of built structures in alpine areas. The compositions, geographic origins, and dominant ruderal strategies of non-native species are similar to those of Arctic and other alpine non-native floras globally. Sørenson similarity index and nonmetric multidimensional scaling ordination of twenty alpine regions reveals the White Mountains have highest similarity with widely separated mountain regions in Australia, Hawaii, the Rocky Mountains, the Andes, Southern Africa, and Iceland, driven by shared species of Eurasian origin. We report the unexpected discovery of Plagiobothrys hispidulus, a borage native to western North America not previously reported from New Hampshire. These findings have important implications for managers of alpine areas in eastern North America and may facilitate the early detection, monitoring, and control of non-native species, minimizing their establishment and spread.

Burn severity and proximity to undisturbed forest drive post-fire recovery in the tropical montane forests of northern Vietnam

BackgroundIn recent decades, fire has increasingly occurred in the tropical montane rainforests of northern Vietnam. However, there are few studies of the effects of fire on forest composition and recovery in this region, and understanding these effects is critical for effective forest fire management and conservation. Forest plant species richness, structure (density, basal area), and composition were quantified for 133 forest plots randomly located in unburned (> 20 years since last fire) and recently burned (3–9 years since fire) vegetation associated with ten selected wildfires in three provinces of northern Vietnam where fires since 2000 were most frequent. Linear mixed effect models and nonmetric multidimensional scaling (NMDS) ordination were used to explore the structure, richness, and composition of burned and unburned forests and their environmental drivers, and to explore the key drivers of regeneration patterns in burned forest, including time since fire occurrence, fire severity, and distance to unburned forest edge.ResultsTotal species richness and diversity, tree species richness, tree density, and basal area were higher in unburned (vs. burned) forest plots, low (vs. high) severity burn areas, near (vs. far) from the closest unburned forest edge, and longer (vs. shorter) time since last fire. Results suggest that while burned forests were recovering on a trajectory back towards unburned forest composition, recovery was likely to be markedly slowed where fires were large (distance from edge effects) and/or of high severity, and forests may shift towards a different state (i.e., composition and structure) where more than one fire affects the same area over short time intervals.ConclusionsThis study provides insights into the effects of fire and other environmental factors on forest composition and recovery in the tropical montane forests of northern Vietnam, crucial for informing policymakers involved in forest conservation and management.

SOIL CHEMICAL ATTRIBUTES RELATIONSHIPS AROUND THE Araucaria angustifolia TREES IN AGROFORESTRY SYSTEMS

This work aimed to understand the relationships between araucaria trees and some abiotic factors (soil type, soil organic C and soil nutrient supply) in agroforestry systems (AFS). Soils of two production areas in south-central region of the state of Parana (Bituruna - B and São Mateus do Sul - M) were characterized and soil chemical attributes were determined in microsites close to araucaria trees. B area presented only “juvenile” trees, while M area was formed by “juvenile” and “adult” trees. According to the multiple linear regression analyses, the soil chemical attributes showed an almost total dependence of the microsites depth. Soil chemical attributes dependence was much more diffuse in relation to the distances from the tree insertion in the soil. The non-metric multidimensional scaling ordination according to soil chemical attributes showed a great overlap of behavior of these tree groups. The chemical attributes comparison generated, to a certain extent, a soil fertility deficiency gradient between the microsites of the three groups of trees (MJ &lt; MA &lt; BJ). AFS with shaded Ilex paraguariensis must consider the replacement of nutrients exported by leaf harvest, which will help in the sustainability of the activity. This includes the environmental services that the AFS promotes by maintaining, or even renewing, of the native trees from the local forest, especially araucaria trees, in a productive system.

A phylogenetic approach identifies patterns of beta diversity and floristic subregions of the Qinghai-Tibet Plateau

Patterns of taxonomic and phylogenetic beta diversity and their relationships with environmental correlates can help reveal the origin and evolutionary history of regional biota. The Qinghai-Tibet Plateau (QTP) harbors an exceptionally diverse flora, however, a phylogenetic perspective has rarely been used to investigate its beta diversity and floristic regions. In this study, we used a phylogenetic approach to identify patterns of beta diversity and quantitatively delimit floristic regions on the Qinghai-Tibet Plateau. We also examined the relationships between multifaceted beta diversity, geographical distance, and climatic difference, and evaluated the relative importance of various factors (i.e., climate, topography and history) in shaping patterns of beta diversity. Sørensen dissimilarity indices indicated that patterns of species turnover among sites dominated the QTP. We also found that patterns of both taxonomic and phylogenetic beta diversity were significantly related to geographical distance and climatic difference. The environmental factors that contributed most to these patterns of beta diversity include annual precipitation, mean annual temperature, climatic gradients and climatic instability. Hierarchical dendrograms of dissimilarity and non-metric multidimensional scaling ordination based on phylogenetic beta diversity data identified ten floristic subregions in the QTP. Our results suggest that the contemporary environment and historical climate changes have filtered species composition among sites and eventually determined beta diversity patterns of plants in the QTP.

Assessing the relation between geodiversity and species richness in mountain heaths and tundra landscapes

ContextRecent studies show that geodiversity—the diversity of Earth's landforms, materials, and processes—has a positive relationship with biodiversity at a landscape scale. However, there is a substantial lack of evidence from finer scales, although this knowledge could improve the understanding of biodiversity patterns.ObjectivesWe investigate whether plot-scale geodiversity and plant species richness (vascular plants, bryophytes, lichens, and total richness) are positively linked in different tundra landscapes.MethodsWe collected geodiversity (presence of different geofeatures) and plant species richness data from 165 sites in three distinct regions: isolated low-lying mountain heaths, and in sporadic and continuous mountain heaths and tundra. We used non-metric multidimensional scaling (NMDS) ordination to explore the correlations between the composition of geofeatures and species richness, followed by univariate and multivariate generalized linear models (GLM), to assess whether georichness is important for species richness.ResultsGeofeature composition was linked to species richness in all regions, as indicated by NMDS ordination. Both univariate and multivariate GLM models showed statistically significant relationship between species richness and georichness in all studied species richness groups in continuous Arctic-alpine tundra. Additionally, there was a positive link between georichness and lichen richness in isolated boreal mountain tops.Main conclusionsWe showed that plot-scale geodiversity has a positive relationship with species richness, yet the effect varies regionally and between species groups. Our study provides strong empirical evidence that geodiversity supports species richness in continuous Arctic-alpine tundra. This information can be used in species richness models but also be applied in biodiversity management and conservation.

Landscape-level variability and insect herbivore outbreak captured within modern forests provides a framework for interpreting the fossil record

Temporal patterns of plant–insect interactions are readily observed within fossil datasets but spatial variability is harder to disentangle without comparable modern methods due to limitations in preservation. This is problematic as spatial variability influences community structure and interactions. To address this we replicated paleobotanical methods within three modern forests, creating an analogous dataset that rigorously tested inter- and intra-forest plant–insect variability. Random mixed effects models, non-metric multidimensional scaling (NMDS) ordinations, and bipartite network- and node-level metrics were used. Total damage frequency and diversity did not differ across forests but differences in functional feeding groups (FFGs) were observed across forests, correlating with plant diversity, evenness, and latitude. Overall, we found higher generalized herbivory within the temperate forests than the wet-tropical, a finding also supported by co-occurrence and network analyses at multiple spatial scales. Intra-forest analyses captured consistent damage type communities, supporting paleobotanical efforts. Bipartite networks captured the feeding outbreak of Lymantria dispar caterpillars; an exciting result as insect outbreaks have long been unidentifiable within fossil datasets. These results support paleobotanical assumptions about fossil insect herbivore communities, provide a comparative framework between paleobotanical and modern communities, and suggest a new analytical framework for targeting modern and fossil outbreaks of insect feeding.