Species Richness Research Articles

Species Composition and Diversity of Zooplankton in Chackferi Stream, Tarai Region, Uttarakhand, India

Present study deals with the analysis of species composition and diversity of zooplankton in Chackferi stream. For this investigation samples were collected by monthly intervals for a period of September 2020 to August 2022. A total of 28 species of zooplankton, belonging to 25 genera across 5 groups were identified such as Protozoa (6 species of 6 genera), Rotifera (10 species of 9 genera), Copepoda (7 species of 5 genera), Cladocera (3 species of 3 genera) and Ostracoda (2 species of 2 genera). Rotifera was the dominant group, comprising (36%) of the zooplankton community in Chackferi stream, followed by Copepoda (25%), Protozoa (21%), Cladocera (11%) and Ostracoda (7%). It was noticed that seasonal composition of zooplankton was highest during summer, moderate in winter and autumn and least in monsoon season. Zooplankton are also considered as a good bio-indicator to assess the pollution status of a stream. Presence of indicator species like Brachionus calyciflorus, Brachionus falcatus and Mesocyclops leuckarti reveals that the stream gets organically polluted and rapidly moving toward a eutrophic condition. Therefore, frequent monitoring and proper treatment should be applied for conservation of the stream and its ecosystem.

Evaluating zooplankton species diversity using environmental DNA and bulk-DNA metabarcoding in the Ulleung Basin of the Southeastern Korean Peninsula in the summer

Accurately investigating the composition of zooplankton species is crucial for monitoring changes in marine ecosystems and assessing biodiversity. In this study, we utilized bulk DNA and environmental DNA metabarcoding in the Ulleung Basin, known for its high zooplankton species diversity among the seas surrounding the Korean Peninsula. Genomic DNA extracted from samples collected during three summer seasons in the survey area was analyzed using high-throughput sequencing of the cytochrome c oxidase I barcode region. We identified 350 species, which were three to six times more than those identified by traditional morphological methods. Furthermore, we observed significant differences in species composition and diversity between bulk DNA and eDNA samples. Notably, eDNA metabarcoding effectively detected species with high swimming ability and those that were difficult to capture using traditional sampling methods. This study underscores the significant impact of sampling methods on research outcomes in zooplankton species diversity studies and highlights the importance of integrating different sampling techniques. Specifically, it suggests the need for the active adoption of non-invasive methods, such as eDNA metabarcoding, for the comprehensive monitoring of diverse biological groups in marine ecosystems.

Drivers of plant biodiversity on cemeteries in the Ruhr Metropolitan Region (W Germany)

Cemeteries are biodiversity hotspots in urban areas, while the drivers of their floristic diversity are poorly understood. We investigated 153 cemeteries in the western Ruhr Metropolitan Region and generated comprehensive species lists of wild plants. Altogether, we found 964 species, equivalent to 53.6% of the flora known from the region. Cluster analysis revealed five distinct cemetery types based on their species composition and prevalence. Subsequently, we used ANOVAs to relate the most effective environmental descriptors identified with a CCA to the five clusters, thus revealing the drivers of species composition. Two of the main clusters had clear regional foci, which could be explained by soil types, while the third main cluster included most of the large cemeteries with many different habitat types, and encompassed sites from the entire study region. Here, the number of species is highest. Two smaller clusters included old historic and Jewish cemeteries, respectively, which were characterized by a smaller number of neophytes and heat indicators. Through the various functional types, the cemeteries contribute to the biodiversity of urban areas like the Ruhr Metropolitan Region and thus counteract the floristic homogenization of cities.

Effects of weed management on soil metagenomic composition in cultivated chickpea fields

Abstract Non-chemical methods, including mechanical and manual weed management are important for improving crop yields and preserving soil microbial diversity. In Tunisia, chickpea cultivation uses a combination of these methods to suppress weeds. This study aimed to evaluate the impact of weeding practices on chickpea (Cicer arietinum L. cultivar REBHA) yield and soil microbial diversity. Field experiments were conducted at the Technical Center for Biological Agriculture in Essaida, Tunisia, using six plots with manual and no weeding treatments. Chickpea yield was measured, and soil samples were collected for metagenomic analysis. Floristic surveys identified 13 weed species, with Chenopodium album L., Rumex acetosa L., and Urtica dioica L. being the most dominant. Seed yield ranged from 23.2 to 26.2 qls/ha in non-weeded plots and from 25.1 to 30.1 qls/ha in weeded plots, showing an increase in yield (11.75%) with manual weeding.
Soil metagenomics revealed changes in bacterial community composition between the two treatments. The dominant phylum was Pseudomonadota, whose relative abundance increased from 24.88% in non-weeded plots to 34.76% in weeded plots. Alpha diversity indices showed lower species richness and diversity in weeded soils, with 62000 OTUs in weeded plots compared to 43202 OTUs in non-weeded plots. Betaproteobacteria and Alphaproteobacteria exhibited higher OTU counts in weeded soils. The Simpson diversity index was lower in non-weeded soils (0.025) than in weeded soils (0.075), indicating a more irregular microbial distribution in non-weeded plots. Thus, manual weeding improved chickpea yield and altered the soil bacterial community, increasing diversity in key microbial taxa. This study highlights the complex interaction between weed management practices and soil microbial ecosystems, which may influence crop productivity.

High functional vulnerability across the world’s deep-sea hydrothermal vent communities

At the nearly pristine hydrothermal vents of the deep sea, highly endemic animals depend upon bacteria nourished by hydrothermal fluids that emerge as outflows from the seafloor. These animals are remarkable in tolerating extreme conditions, including high heat, toxic reduced sulfide, and low oxygen. Here, we test whether the extreme vent environment has selected for functionally similar species across the world's deep ocean, despite well-established global geographic patterns of high phylogenetic distinctness. High functional redundancy in species pools within regions suggests that the extreme environments select for species with specific traits. Yet, some regions emerge as functional hotspots where species pools with distinct functional trait compositions may represent geological idiosyncrasies of the habitats. Moreover, many species are functionally unique, an outcome of low species richness in a system where the species pool is small at all scales. Given the high proportion of functionally unique species, simulated species extinctions indicate that species losses would rapidly translate to the elimination of functionally irreplaceable species and could tip vent systems to functional collapse. Ocean changes and human-induced threats are expected to significantly impact many vent species as human activities expand in the remote deep sea. The opportunity exists now to take precautionary actions to limit the rates of extinction now ubiquitous in more accessible areas of Earth.

Extinction and Ecosystem Function Debt Across Dispersal Rate and Behaviour in a Heterogeneous Metacommunity Model

ABSTRACTAimHabitat destruction causes “extinction debt” and is also thought to produce ecosystem function debt, but theory of their magnitude and nature is limited. Heterogeneous landscapes are fundamental to the maintenance of species richness and ecosystem function, while directed or undirected dispersal behaviour, such as dispersal of seeds by animals or by the wind, is also important, especially after habitat destruction. We therefore consider extinction and ecosystem function debt under different dispersal rates and behaviours in heterogeneous landscapes.MethodsWe use a classic heterogeneous metacommunity model to capture the dynamics of competing species in local patches linked by dispersal and varying in environmental conditions. We remove one patch at a time and measure extinction debt and ecosystem function debt by the number/proportion of delayed extinctions and the amount of biomass change, respectively.ResultsWe reveal three species extinction regimes as dispersal increases: (1). species most adapted to the removed habitat are most at risk; (2). similarly adapted species are also at risk; (3). patch removal shifts competitive balance among the few species coexisting at high dispersal, where competition is strong. We find surprisingly that destruction of habitat can hasten the extinction of those species best adapted to harsh environments and that the proportion of diversity at risk from extinction actually increases with dispersal because competition is intense there. Finally, there can be a small ecosystem credit but extinction debt when dispersers reroute to potentially more favourable remaining habitats (directed dispersal), especially when harsh environments are removed. However, ecosystem debt occurs and can be large under undirected dispersal.Main ConclusionsThe magnitude and nature of extinction and ecosystem function debts depend on species dispersal rates and behaviours, as well as the environmental conditions of the disturbed habitats. Conservation actions will be more successful if they consider these factors.

Possibilities of competitive displacement of Bactrocera dorsalis (Hendel) by Bactrocera zonata (Saunders) (Tephritidae: Diptera) in guava Psidium guajava ecosystem in Sudan

Oriental fruit fly (OFF) Bactrocera dorsalis and peach fruit fly (PFF) Bactrocera zonata are the most notorious pests that invaded Sudan in 2005 and 2012, respectively, causing severe losses and hindering horticultural production and exports. Prior to 2012, OFF was the most abundant fly in guava orchards in Gezira State. Monitoring fruit flies to determine species composition, seasonality, and possibilities of competitive displacement was conducted in two guava (Psidium guajava) orchards in Gezira State; Fadasi and Gezirat Elfil, using food bait attractant and rearing flies from infested fruits..Longevity and survival percentages of developmental stages of the two species were also determined. Monitoring fly populations using Torula yeast and rearing of fruit flies from guava fruits revealed that OFF and PFF were the most prevalent species in guava ecosystem at both sites. At the Fadasi site, PFF was the predominant species representing (99.3%) of the guild of the trapped flies with an infestation level of 99.6%) flies/kg of guava fruits. At G. Elfil, OFF comprised 80.8% of the trapped flies with infestation level ca 53.6% while 19.2% of trapped flies were B. zonata with 46.4% infestation level. The high percentage of trapped OFF at G. Elfil might be attributed to multi-cropping system in the area. Developmental stages of PFF were shorter than that of OFF by 9.2 days, while its survival percentage was higher than that of OFF for all developmental stages. Competitive displacement of OFF by PFF in guava orchards at Fadasi site may have occurred as a result of the mono-cropping system, short developmental period, and high survival percentage of developmental stages of PFF on guava compared to that of OFF.

Defaunation impacts on the carbon balance of tropical forests.

The urgent need to mitigate and adapt to climate change necessitates a comprehensive understanding of carbon cycling dynamics. Traditionally, global carbon cycle models have focused on vegetation, but recent research suggests that animals can play a significant role in carbon dynamics under some circumstances, potentially enhancing the effectiveness of nature-based solutions to mitigate climate change. However, links between animals, plants, and carbon remain unclear. We explored the complex interactions between defaunation and ecosystem carbon in Earth's most biodiverse and carbon-rich biome, tropical rainforests. Defaunation can change patterns of seed dispersal, granivory, and herbivory in ways that alter tree species composition and, therefore, forest carbon above- and belowground. Most studies we reviewed show that defaunation reduces carbon storage 0-26% in the Neo- and Afrotropics, primarily via population declines in large-seeded, animal-dispersed trees. However, Asian forests are not predicted to experience changes because their high-carbon trees are wind dispersed. Extrapolating these local effects to entire ecosystems implies losses of ∼1.6 Pg CO2 equivalent across the Brazilian Atlantic Forest and 4-9.2 Pg across the Amazon over 100 years and of ∼14.7-26.3 Pg across the Congo basin over 250 years. In addition to being hard to quantify with precision, the effects of defaunation on ecosystem carbon are highly context dependent; outcomes varied based on the balance between antagonist and mutualist species interactions, abiotic conditions, human pressure, and numerous other factors. A combination of experiments, large-scale comparative studies, and mechanistic models could help disentangle the effects of defaunation from other anthropogenic forces in the face of the incredible complexity of tropical forest systems. Overall, our synthesis emphasizes the importance of-and inconsistent results when-integrating animal dynamics into carbon cycle models, which is crucial for developing climate change mitigation strategies and effective policies.

Small Streams Support Beta Diversity in Neotropical Fish Assemblages in the Upper Paraná River Basin

ABSTRACTVariation in species composition along an environmental gradient (β‐diversity) can inform our understanding of biodiversity patterns and species composition. Beta diversity can be partitioned into species contributions to beta diversity (SCBD) and local contributions to beta diversity (LCBD). While SCBD describes the variations in species composition among samples, LCBD measures the uniqueness of a biological community within a larger ecosystem. Recently developed metrics enabled the estimation of species contribution to total beta diversity (SCBD) and the contribution of individual sites to total beta diversity (LCBD). Utilising these metrics, a one‐time survey of 275 sampling points within four sub‐basins of the Upper Paraná River Hydrographic Basin (low‐flow streams, < 5 m3/s) was conducted to assess fish community composition. Our results show that limnological influences at different scales contribute to higher LCBD. However, land use and species richness were not directly linked to this outcome, suggesting that sites with fewer fish species along sub‐basins contributed to higher beta diversity. It was concluded that beta diversity is more influenced by limnological characteristics and the position of sampling sites along the longitudinal gradient than that based on variations in species composition (SCBD). Moreover, high LCBD values were even found in portions of the gradient with lower species richness. This means that small streams in the sub‐basins of the upper Paraná River are unique and are comprised of varied habitats that contribute to increasing diversity. As such, they should be seen as a target in the development of environmental policies designed to conserve their pristine condition.

Planting native trees in degraded grassy woodland does not restore species composition

SummaryRestoration of degraded former Cumberland Plain Woodland by planting of native trees and shrubs was undertaken by Greening Australia (NSW) on the Cumberland Plain, west of Sydney, Australia, from the mid‐1990s. Our study examined the success of this restoration in stands of two ages using species composition as the criterion. The starting point (pasture) and the target (reference woodland) were sampled to document the extent of progress of species composition from pasture through young (3–5 years) and old (9–11 years) restoration stands to reference woodland across three sites at two surveys. Comparisons showed restored stands of both ages differed significantly from pasture, and from each other, showing decreasing similarity between the restoration stands and pasture at all sites. Despite this, species composition in restored stands at all three sites was still significantly different from reference sites, showing that none had achieved the target reference state after 11 years. The trajectory of restored sites between the two surveys was not towards the reference state. Restoration resulted in the establishment of 20 (71%) of the planted species. Recruits from five planted species were found. A further 40 unplanted native ground layer species were found in restoration. Structurally, tree cover increased with time since restoration and was higher in the restored sites. Ground cover, which was very high in pasture was lower in some restored sites. The majority of the unplanted native species were resprouters, and their presence in the above‐ground vegetation was most likely by vegetative resprouting from the bud‐and‐tuber bank as ground cover was lower with the increase in tree cover and shade. Tree and shrub planting by itself has not yet progressed the restored areas to the species composition of reference sites. Additional tools will be needed to assist restoration, specifically the addition of re‐seeder native plants not able to persist through vegetative resprouting after restoration. Measures to control the burden of weeds present in the pasture seed bank are also required.

Socioeconomic Status and Local Biodiversity as Predictors of Attitudes towards Nature among High School Students in a Latin American Metropolis.

Urbanization and biodiversity loss disconnect humans from nature and may limit pro-environmental actions. Although, a growing body of knowledge exists on people's attitudes towards nature, the majority focuses on the influence of socio-environmental factors. Significant variations in socioeconomic and educational levels in urban areas affect access to biodiversity. In this study, we aim to identify the socio-environmental variables that are associated with people's attitudes towards nature (student's knowledge about urban birds and their participation in conservation actions). We collected data on local biodiversity, socioeconomical status, and high school students' attitudes towards nature (15 schools, n = 175 students) in a large Latin American capital city. Structural equation modeling (SEM) was utilized to identify relationships among all variables. Socioeconomic characterization was assessed using levels of socio-materiality and school performance scores. Definitions of ecological complexity were based on bird species richness and vegetation density. Knowledge of urban birds was evaluated using two indicators: urban bird identification (recognition of names) and identification of the biogeographic origin of urban birds (native or exotic). Participation in conservation actions by students was assessed based on implementation scale and implementation frequency. According to our results, respondents' knowledge of birds was poor: 42% of students identified only two species (the domestic pigeon and the monk parakeet, both exotic). Only 26% of total students participated in conservation actions. SEM analysis revealed that socioeconomic status was positively associated with the ecological complexity of surrounding areas. In turn, ecological complexity showed a positive relationship with students' knowledge on urban birds. Finally, students' knowledge of urban birds showed a positive influence on conservation actions. Our findings suggest that, the improvement of students' knowledge about local biodiversity and ensuring equitable access to biodiversity could be an effective way to foster students' involvement in conservation actions, especially in neighborhoods of lower socioeconomic levels.

Lessons from long‐term research: Diptera species turnover and dominance shifts with respect to climate‐driven changes

Abstract The diverse pressures of climate change have influenced many habitats, especially freshwater ones, due to their greater sensitivity to stressors. Aquatic Diptera make up more than 50% off all aquatic insect species described, which makes them an ideal group to monitor changing climate as their diverse assemblages can reflect functions within the entire community. The aim of this research was to identify variations in the aquatic dipteran community during a 15‐year period at a tufa barrier in a karst barrage lake system and to determine the environmental factors that have the highest influence on this community. We analysed monthly data collected between 2007 and 2021, when we collected adult specimens using 6 pyramid‐type emergence traps. In total, 167 taxa from 13 different families were gathered. NMDS based on Bray–Curtis similarity analysis amongst assemblages revealed the segregation of samples based on different current velocities and substrates, indicating the importance of microhabitats in dipteran community structuring. Dipteran taxa indicative of specific 5‐year time periods within the research were identified and were associated with changes in environmental conditions especially discharge. The threshold indicator taxa analysis revealed specific species' responses to changing discharge rates. The study shows that discharge rate, not water temperature, is the critical factor shaping dipteran composition, whether by removing or adding taxa to the community. Species turnover showed an overall decrease in species numbers, that is, species richness, throughout the research period. We conclude that changes in the dipteran community, because of the vast functional traits, niches, adaptations and species diversity of the group, are not visible when analysing just the diversity indices. When determining environmental influence on the community in long‐term research, they should be combined with other data such as the overall abundance, the total number of species, as well as the species turnover.

Discovery of a new Kinorhyncha species from the uncharted South Orkney Trench (Southern Ocean)

The knowledge about the deep-sea Kinorhyncha community has increased considerably in recent years. However, the records of kinorhynchs inhabiting hadal depths are still extremely limited. In the present study, we describe a new species of Echinoderes discovered from the South Orkney Trench, Southern Ocean. Echinoderes australis sp. nov. is characterized by the presence of middorsal acicular spines on segments 4-8 and lateroventral ones on segments 6-9, and tubes in lateroventral position on segment 5, in lateral accessory position on segment 8, and in laterodorsal position on segment 10. Additionally, the new species has conspicuous papillary flaps on segments 8-9. Among its morphological characteristics, the increase in length of the middorsal spine of segment 8 and lateroventral spines of segment 9 in relation to those of the previous segments are striking features, showing a whip-like appearance. E. australis sp. nov. Becomes the third hadal species of the phylum. In addition, we provide morphological information on the two other species found in the trench. Finally, we study in detail the diversity and distribution patterns of the Kinorhyncha of the South Orkney Trench, addressing aspects such as species richness, abundance, number of adults versus juveniles and the effect of bathymetry on the community composition.

Spatial Variation in Upper Limits of Coral Cover on the Great Barrier Reef

ABSTRACTAimIdentifying the maximum coral cover that a coral community can sustain (i.e., its ‘upper limit’) is important for predicting community dynamics and improving management strategies. Here, we quantify the relationship between estimated upper limits and key environmental factors on coral reefs: hard substrate availability, temperature and water clarity.LocationGreat Barrier Reef (GBR), Australia (over 1400 km).Time Period1990 to 2022.Major Taxa StudiedScleractinian corals.MethodsWe used 32 years of data on coral cover around reef perimeters. Each reef was divided into four wave‐exposure habitats depending on prevailing wind conditions. For each site, we determined if hard coral cover had reached a plateau or upper limit. Next, we extracted existing estimates of hard substrate availability, modelled water temperature and Secchi depth. Then, we quantified the relationship between these environmental variables and the upper limits.ResultsWe found varying upper limits across the GBR, with a median of 33% coral cover and only 17% of the estimated upper limits exceeded 50% coral cover. Upper limits increased towards the southern reefs. Our results show that upper limits increased with increasing hard substrate availability and decreased with temperature and, to a lesser extent, with water clarity.Main ConclusionsThe upper limits estimated in this study are much lower than what is commonly assumed when modelling ecological dynamics, most likely resulting in predicted recovery rates being inappropriately high. Although hard substrate ultimately restricted upper limits, there are mechanisms constraining the proportion of hard substrate that is covered by hard corals. The negative relationship between temperature and upper limits cannot be explained by changes in macroalgal abundance but may be related to changes in species composition. The quantitative relationships between the upper limits of coral cover and environmental variables will provide critical information to prioritise sites for management interventions.

Exploring riverine aquatic animal diversity and establishing aquatic ecological monitoring approaches tailored to the Qinling region via eDNA technology.

This study thoroughly examines biodiversity and aquatic ecosystems across 14 sampled sites within the Shitou River basin by utilizing environmental DNA technology. Through integrated analysis and high-throughput sequencing, the study elucidates a diverse array of biodiversity, encompassing 27 fish species and 341 freshwater benthic macroinvertebrates (FBM) species. Using various biodiversity indices, we found significant differences in diversity and stability across different environments. Regions with more complex habitats had higher species richness and evenness. Further analyses showed complex relationships between diversity metrics for FBM and fish, indicating potential interactions between these groups. The standardized mean score (SMS) was developed to aid in the assessment of water quality. Specifically, SMS scoring revealed that sites STH3, STH4, and STH14 excelled across multiple dimensions, earning an "Excellent" rating, while site STH12 was rated as "Poor" due to subpar performance across several metrics. This project not only enhances current understanding regarding aquatic ecological dynamics but also establishes a strong foundation for detailed environmental evaluation and monitoring, aligned with the priorities of contemporary ecological management and caution.

Aplikasi Sistem Pakar Kopi Mendeteksi Hama Kopi Di Desa Telagah Kecamatan Sei Bingai Kabupaten Langkat

The use of coffee expert applications can help farmers detect pest attacks based on symptoms of attacks on coffee plants. This study aims to determine the application of the coffee expert system to coffee farmers, determine the diversity of insect species and pest status on coffee plants in Telagah Village, Sei Bingai District, Langkat Regency, North Sumatra. Insect identification was carried out by the Plant Pest Laboratory, Faculty of Agriculture, University of Sumatra Utara which was carried out from July to August 2023. This study used purposive sampling method with yellow sticky trap. The results showed insects caught as many as 10 orders, 21 families, 25 genera as many as 4743 individuals. The results of the analysis of Coffee Experts detected Hypothenemus hampei pest attack = 6.80%. Diversity Index (H') = 1.91, evenness index (E) = 0.59 and species richness index (R) = 8,46. The use of coffee expert applications can help farmers detect pests appropriately.

WATER INHABITING BIRDS OF MAIGANGA POST COAL MINING PONDS AND ARTIFICIAL WETLAND

Wetlands play a significant role in bird conservation and generally support biological diversity. Historically, bird community assessment has been employed in monitoring and identifying areas for conservation actions. In this study, we examined two post mining ponds and one artificial wetland in Maiganga Coal Mine, Gombe State for wetland avifauna. We focused on water birds (i.e. bird species that depend wholly or partially on water and wetland ecosystems for their survival). Survey was conducted during the onset of dry season in October 2021 to September 2022. Point count technique was used for the survey. A total of 626 individuals of 23 species from 19 genera, 10 families and 6 bird Order were recorded. The White-faced whistling duck was the most abundant bird species and was restricted to the active-mine pond (AMP). AMP was the most diverse of the three water bodies surveyed. However, some species were exclusive to either of the three sites. Similarly, AMP was the most abundant site with 426 individuals from 16 bird species, followed closely by the sedimentation pond with 147 individuals drawn from 15 bird species. The results suggest that water depth, age of establishment and surrounding vegetation structure could be a major determinant of bird species composition and abundance in the study area. The study highlights the importance of restorative actions aimed at recovering modified landscapes, through tree planting and creation of wetlands. This is evident in the presence of waterbirds in Maiganga, a location that was previously devoid of perennial water bodies and...

Habitat Fragmentation Affects Richness—A View Through a Metacommunity Lens

Habitat fragmentation is often assumed to negatively impact species diversity because smaller, more isolated populations on smaller habitat patches are at a higher extinction risk. However, some empirical and theoretical studies suggest that landscapes with numerous small habitat patches may support higher species richness, although the circumstances remain elusive. We used an agent-based metacommunity model to investigate this and simulate landscapes of the same total area but diverse patch sizes. Our model, as generic and unbiased by specific assumptions as possible, aimed to explore which circumstances may be more conducive to supporting higher biodiversity. To this end, most parameters and behaviors were random. The model included generalized species traits, dispersal, and interactions to explore species richness dynamics in fragmented landscapes of distinct patch sizes. Our results show that landscapes with many small patches maintain higher species richness than those with fewer large patches. Moreover, the relationship between patch connectivity and species richness is more pronounced in landscapes with smaller patches. High connectivity in these landscapes may support species diversity by preventing local extinctions and facilitating recolonization. In contrast, connectivity is less significant in large-patch landscapes, where generalist species dominate. The findings highlight the complex interplay between patch size quality, connectivity, species traits, and diverse interactions among species in determining species richness. We suggest the patterns produced by the model represent null predictions and may be useful as a reference for a diversity of more specialized questions and predictions. These insights may also have specific implications for conservation strategies, suggesting that maintaining a mosaic of small, well-connected patches could enhance biodiversity in fragmented landscapes.

Continental sampling reveals core bacterial and environmentally driven fungal leaf endophytes in Heuchera.

Endophytic plant-microbe interactions range from mutualistic relationships that confer important ecological and agricultural traits to neutral or quasi-parasitic relationships. In contrast to root-associated endophytes, the role of environmental and host-related factors in the acquisition of leaf endophyte communities at broad spatial and phylogenetic scales remains sparsely studied. We assessed endofoliar diversity to test the hypothesis that membership in these microbial communities is driven primarily by abiotic environment and host phylogeny. We used a broad geographic coverage of North America in the genus Heuchera L. (Saxifragaceae), representing 32 species and varieties across 161 populations. Bacterial and fungal communities were characterized using 16S and ITS amplicon sequencing, respectively, and standard diversity metrics were calculated. We assembled environmental predictors for microbial diversity at collection sites, including latitude, elevation, temperature, precipitation, and soil parameters. Assembly patterns differed between bacterial and fungal endophytes. Host phylogeny was significantly associated with bacteria, while geographic distance was the best predictor of fungal community composition. Species richness and phylogenetic diversity were consistent across sites and species, with only fungi showing a response to aridity and precipitation for some metrics. Unlike what has been observed with root-associated microbial communities, in this system microbes show no relationship with pH or other soil factors. Overall, this work improves our understanding of the large-scale patterns of diversity and community composition in leaf endophytes and highlights the relative significance of environmental and host-related factors in driving different microbial communities within the leaf microbiome.

Biodiversity measures of a grassland plant-pollinator community are resilient to the introduction of honey bees (Apis mellifera).

The prairies of Canada support a diversity of insect pollinators that contribute pollination services to flowering crops and wild plants. Habitat loss and use of managed pollinators has increased conservation concerns for wild pollinators, as mounting evidence suggests that honey bees (Apis mellifera) may reduce their diversity and abundance. Plant-pollinator community analyses often omit non-bee pollinators, which can be valuable contributors to pollination services. Here, we experimentally introduced honey bees to examine how their abundance affects the species richness, diversity, abundance, species composition, interaction richness, and interaction diversity of all wild pollinators, and of four higher taxa separately. We identified all insect pollinators and analyzed how honey bee abundance affected the above biodiversity metrics, controlling for flower abundance and flower species richness. Even with high honey bee densities, there was no change to any of these variables, except that beetle species diversity increased. All other taxa had no significant relationship to honey bee abundance. Considering the widespread use of managed honey bees, the effect they have on wild pollinators should be firmly established. Our results suggest that honey bees have little to no short-term impact on the wild pollinator community or its interactions with plants in this native grassland.