Richness Estimates Research Articles

Assessing electrofishing effort required to estimate species richness of fishes in nonwadeable rivers of Alabama, USA

AbstractObjectiveMuch of the fish biodiversity in the southeastern USA is found in lotic systems, but assessment of fish community structure in large nonwadeable rivers has lagged compared to streams. Sampling designs that adequately estimate species richness are a prerequisite to creating bioassessment metrics but thus far has not been attempted in highly biodiverse rivers in the southeastern USA east of the Mississippi River.MethodsFish communities in four nonwadeable rivers across Alabama spanning catchments of 2046–57,415 km2 were sampled using electrofishing in summer and fall of 2015 and 2016. All rivers were sampled during day; two rivers were also sampled at night to assess diel changes in species accumulation.ResultIn total, 55,239 fishes were collected across rivers, representing 106 species in 24 families. Species collected continued to increase as sampling increased in all river‐season combinations, rarely displaying an asymptote. Species generally accrued more quickly and accumulation curves showed more tendency to asymptote in fall than summer in all but the largest river. Species accumulated faster at night than during the day in both rivers during summer but was similar between diel periods in fall. On average, 95% of the species observed were collected in eight subreaches in fall but not until nine during summer; however, observed number of species was generally one to six species lower than mean estimates of true species richness. Sampling efforts collected approximately similar species assemblages across transects, years, season, and diel periods. Extrapolation of species accumulation curves suggested that 6–17 km of sampling distance would be required to collect all species present.ConclusionResults of this study demonstrate that assessing fish communities in species nonwadeable rivers requires an inordinate amount of sampling effort, which may be unattainable for many agencies. Further study is warranted to develop innovative solutions to overcome these logistical challenges.

Observations on the Antagonistic Relationships between Fungi, Archaea, and Bacteria in Livingston Island (Maritime Antarctica) with the Use of Amplicon-Based Metagenomics

An amplicon-based metagenomic survey of archaea, fungi, and bacteria was performed on Livingston Island, Maritime Antarctica. In many of the samples, patterns of antagonism between these three superkingdoms were observed in the form of an inversely proportional dependence of the richnesses of the three types of microorganisms. The antagonism was quantified—based on the observed numbers of the total tags and the numbers of the operational taxonomic units (OTUs), and on four alpha diversity parameters—using the Shannon, the Simpson, the Chao1, and the ACE indices. We found that the most discriminative results in the antagonism measuring were obtained when the numbers of the OTUs and the ACE community richness estimator were compared. The antagonism between archaea and fungi was most potent, followed by that of archaea and bacteria. The fungi–bacteria antagonism was slightly detectable. Pearson and Spearman correlation analyses also showed a statistically significant negative correlation between the fungal and archaeal effective tags, while the correlation between archaeal and bacterial diversity was positive. Indications of the order of primary microbial succession in barren ecological niches were also observed, demonstrating that archaea and bacteria are the pioneers, followed by fungi, which would displace archaea over time.

Nonparametric richness estimators Chao1 and ACE must not be used with amplicon sequence variant data.

Microbial ecologists use alpha diversity metrics for estimating species richness and evenness from data obtained by high-throughput sequencing of small subunit ribosomal RNA genes. This perspective argues that the nonparametric richness estimators Chao1 and ACE should never be used with ASV data because the default process of generating amplicon sequence variants (ASVs) removes singletons, which are specifically required for these estimate calculations. In addition, retaining singletons, if/when possible, will contribute a large proportion of artifacts to this abundance category, leading to extreme richness overestimation. We recommend the use of alternative sequence clustering strategies and/or diversity metrics to avoid generating meaningless richness estimates from ASV data.

Ecologically informed priors improve Bayesian model estimates of species richness and occupancy for undetected species.

Detection error can bias observations of ecological processes, especially when some species are never detected during sampling. In many communities, the probable identity of these missing species is known from previous research and natural history collections, but this information is rarely incorporated into subsequent models. Here, I present prior aggregation as a method for including information from external sources in Bayesian hierarchical detection models. Prior aggregation combines information from multiple prior distributions, in this case, an ecologically informative, species-level prior, and an uninformative community-level prior. This approach incorporates external information into the model without sacrificing the advantages of modeling species in the context of the community. Using simulated data supplied to a multispecies occupancy model, I demonstrated that prior aggregation improves estimates of (1) metacommunity richness and (2) environmental covariates were associated with species-specific occupancy probabilities. When applied to a dataset of small mammals in Vermont, prior aggregation allowed the model to estimate occupancy correlates of the Eastern cottontail Sylvilagus floridanus, a species observed at several sites in the region but never captured. Prior aggregation can be used to improve the analysis of several important metrics in population and community ecology, including abundance, survivorship, and diversity.

Distribution and Endemism Areas of Bonamia Thouars (Convolvulacea) in Brazil.

Brazil harbors the highest richness of Convolvulaceae with 424 species recognized mainly distributed in the Amazon, Atlantic Forest, Caatinga and Cerrado phytogeographic domains. Seventeen of these species are representatives of Bonamia, with ten endemic to the country. The aim of the study was to map the distribution of this group to understand its richness, its sampling and detecting areas of endemism, valuable information for conservation. We collected data gathered from herbaria and from the online database. The data were refined (1) excluding of records not at the species level; (2) records with no identification of collection site or with only the identification of the state of collection. There was calculated the richness, the number of records and an estimate of richness per cell. We conducted a parsimony analysis of endemism for distribution analysis. Finally, the knowledge of richness for the species was analyzed. There were gathered 420 occurrence records, in 87 grid cells. Most grid cells observed in the study presented one species. Two endemic areas were found for the genus. The results contribute to the understanding of the distribution of the group in Brazil, highlighting shortfalls in collections.

Exploring coral speciation: Multiple sympatric Stylophora pistillata taxa along a divergence continuum on the Great Barrier Reef.

Understanding how biodiversity originates and is maintained are fundamental challenge in evolutionary biology. Speciation is a continuous process and progression along this continuum depends on the interplay between evolutionary forces driving divergence and forces promoting genetic homogenisation. Coral reefs are broadly connected yet highly heterogeneous ecosystems, and divergence with gene flow at small spatial scales might therefore be common. Genomic studies are increasingly revealing the existence of closely related and sympatric taxa within taxonomic coral species, but the extent to which these taxa might still be exchanging genes and sharing environmental niches is unclear. In this study, we sampled extensively across diverse habitats at multiple reefs of the Great Barrier Reef (GBR) and comprehensively examined genome-wide diversity and divergence histories within and among taxa of the Stylophora pistillata species complex. S. pistillata is one of the most abundant and well-studied coral species, yet we discovered five distinct taxa, with wide geographic ranges and extensive sympatry. Demographic modelling showed that speciation events have occurred with gene flow and that taxa are at different stages along a divergence continuum. We found significant correlations between genetic divergence and specific environmental variables, suggesting that niche partitioning may have played a role in speciation and that S. pistillata taxa might be differentially adapted to different environments. Conservation actions rely on estimates of species richness, population sizes and species ranges, which are biased if divergent taxa are lumped together. As coral reefs are rapidly degrading due to climate change, our study highlights the importance of recognising evolutionarily distinct and differentially adapted coral taxa to improve conservation and restoration efforts aiming at protecting coral genetic diversity.

Mammal inventory using camera traps in the Central Forest State Nature Reserve (West of European Russia)

A mammal species inventory by estimating their richness is the first and necessary task of any mammal monitoring programme. This paper presents estimates of species richness of mammals (mostly medium and large body-sized) in the Central Forest State Nature Reserve (European Russia). Based on data collected in 2023 from 55 camera trap locations (19 676 camera days), 59 035 images of wild mammals were obtained. A total of 18 species were recorded. Of these, ten species were representatives of the Carnivora, four – Artiodactyla, two – Rodentia, one – Erinaceomorpha, and one – Lagomorpha. This amounted to 84% of all potentially camera-trapped mammals observed in the Central Forest State Nature Reserve. The relative abundance index (RAI) and naïve occupancy (ψnaive) were calculated for all species. The most common and frequently recorded were Meles meles (RAI = 4.95; ψnaive = 0.96), followed by Ursus arctos (RAI = 4.39; ψnaive = 1) and Lepus timidus (RAI = 4.08; ψnaive = 1), while the most rarely recorded species were Castor fiber (RAI = 0.01; ψnaive = 0.02), Erinaceus europaeus (RAI = 0.02; ψnaive = 0.04), and Lutra lutra (RAI = 0.03; ψnaive = 0.07). Large and medium-sized carnivorous and omnivorous mammal communities were the fastest and most completely captured. According to the constructed single-season multispecies occupancy model with Markov chains Monte Carlo, camera traps failed to record 4–5 more possible species. These species are likely to be Mustela lutreola, M. erminea, and Mustela nivalis, as well as two invasive species, Cervus nippon and Capreolus pygargus. All the captured species were recorded in total in a short period of time, namely from the end of March to the beginning of May during 1869 camera-days. Two of them (Castor fiber and Erinaceus europaeus) were recorded exclusively at this time, and they were not captured further until the end of the year. This emphasises the importance of conducting mammal inventory, with inclusion of the spring season.

Sampling origins and directions affect the minimum sampling area in forest plots

AbstractQuestionsThe minimum sampling area (minimum area) is the smallest space that reflects species composition and characteristics of a plant community. The quantitative concept of minimum area is often estimated using species–area relationships (SARs) and has become the classical foundation for managing protected areas. However, sampling designs to determine the minimum area in different forest types have not been systematically evaluated.LocationChina.MethodsWe used tree census data from three forest dynamic plots, each with a size of 25–60 ha, in different climatic zones in China to determine the minimum areas of woody plants and to analyze the effects of species richness and topographic heterogeneity on the minimum areas by changing sampling origin and direction.ResultsWe found that mainly sampling design affects the estimation of woody plant species richness and required minimum area in different forest types. The estimated size of the minimum areas required was several hectares and varied significantly with sampling origin and direction, and showed a difference of approximately 1.5–2 times in the forest plots. Topographic heterogeneity significantly affected the minimum area through changes in species composition.ConclusionsSampling origin and direction should be considered when using SARs to estimate the minimum area and species diversity in communities. Such a comprehensive approach of sampling can contribute to a better understanding of vegetation characteristics and the minimum area required for a conservation census in heterogeneous environments.

Distribution of Subgingival Bacteria in Chronic Periodontitis Patients Correlated with IgA Nephropathy.

Several studies indicated that chronic periodontitis (CP) and its subgingival bacteria correlated with IgA nephropathy (IgAN). Previous research has shown that prevalence of IgAN in chronic periodontitis patients is significantly higher than that in non CP patients in Xinjiang especially in ethnic Uyghur. The aim of this study is to investigate the distribution of plaque bacterial microbes in CP and IgAN patients and to find correlation between CP and IgAN. All of the subgingival plaque samples including 7 healthy controls (N group), 8 CP patients, 14 IgAN patients, and 14 CP with IgAN patients were obtained from ethnic Uyghur people. To investigate the distribution of plaque microbe in Uyghur CP and IgAN patients, the 16s rRNA sequencing and comparative analysis of subgingival bacteria were performed. There were no statistically differences in the community richness estimator (Chao) and the diversity estimator (Shannon index) among four groups. The abundance of Burkholderiales (order), Ottowia (genus) in the plaque microbes were significantly higher in CP with IgAN patients than CP patients. The abundance of Eubacterium (genus) was significantly higher in CP with IgAN patients than IgAN patients. The abundance of Veillonella (genus) was significantly higher while Streptococcus (genus), Tannerella (genus) were significantly lower in CP patients than healthy volunteers. The composition and abundance of subgingival plaque microbes in Uyghur CP and IgAN patients were significantly different at several levels. Which suggested that abundance of subgingival bacteria is correlated to CP and IgAN.

Experiences of discrimination are associated with microbiome and transcriptome alterations in the gut.

Discrimination is a recognized psychosocial stressor that has been linked to various negative health outcomes. This study explored the impact of discrimination on gut health, specifically focusing on microbiome changes, predicted metagenomic differences, transcriptomic profiles, and the potential for using a multi-omic approach to predict discrimination to identify discrimination status for an individual. Methods: We conducted a comprehensive investigation involving male and premenopausal female participants, using the Everyday Discrimination Scale to classify them into either high or low discrimination. Multiple questionnaires were administered to evaluate participants' physiological, psychological, and perceived stressors. Two diet questionnaires were also administered. Stool samples were collected for microbiome analysis and RNA sequencing. Microbial composition changes were analyzed using the Shannon index and Chao1 richness estimator for alpha diversity and the Aitchison distance metric for beta diversity. Differential abundance was evaluated using MaAsLin2, followed by metatranscriptomics sequencing and annotation. A multi-omic approach utilizing random forest was used to assess the predictability of discrimination. The study results showed that high discrimination was linked to higher gut microbiome species richness (Chao1, p = 0.02) and significant beta diversity differences (p = 0.04). Prevotella and Ruminococcaceae were both less abundant in the high discrimination group. High discrimination participants also reported higher levels of depression, anxiety, perceived stress, early life adversity, visceral sensitivity, and neuroticism than those in the low discrimination group. Gene expression analysis revealed distinctive patterns, with significant changes in genes associated with environmental sensing (two-component system) and metabolic pathways. In a plot comparing gene transcription to DNA content, certain genes showed higher expression levels in participants who experienced both high and low levels of discrimination. Our random forest classifier demonstrated the capability to accurately differentiate individuals with high and low discrimination in our training cohort (AUC = 0.91). These findings illuminate the substantial impact of discrimination on gut health, encompassing microbiome composition, gene expression, and functional pathways. These findings suggest that discrimination is associated with internal biological changes that can be associated with negative health outcomes, opening research to examine novel pathways that can be used to mitigate the negative health effects of discrimination.

Revealing floristic and structural variation in regenerating areas in the Cerrado-Caatinga transition: an analysis across seres

Abstract In the savanna-seasonally dry tropical forest ecotone in Northeastern Brazil, we studied variations in flora and structure within old growth and two sites in secondary succession (10 and 25 years). We sampled 2,127 trees and shrubs with a diameter at ground level of 3 cm or more, excluding cacti, palm trees, and vines. Old growth contained 478 plants from 29 species, the 25-year site had 819 plants from 27 species, and the 10-year site had 829 plants from 25 species, totaling 38 species across the sites. Regarding the regenerating stratum, we found 2,776 individuals, with the largest and smallest number of individuals for 10 and 25 years regeneration, respectively. Rarefaction and Jacknife richness showed greater tree richness in old growth, whereas 10 and 25 years regeneration presented similar richness estimates; furthermore, the highest richness in the regenerating stratum was observed in 10 years and the lowest in old growth. Our results reveal that changes in composition are caused by species replacement, demonstrating that even in areas deforested for traditional agriculture, turnover causes significant changes in composition and results in the requirement of a long time for reestablishment, similar to the old growth.

Floristic diversity and edaphic filters in an urban forest under Cerrado domain, in Cuiabá, Central Western Brazil.

We aimed to characterize the adult and regenerating tree components and their relationships with soil characteristics of a native vegetation remnant in Cuiabá, Mato Grosso, Brazil. The area of the fragment is stratified into "dry area" (lithic neosoil) and "damp area" (gleisoil). We conducted a forest inventory with a random distribution of 25 parcels. We analyzed the physical and chemical components of the soil. We evaluated the vegetation's horizontal structure, diversity, and sample sufficiency using the Bootstrap richness estimator. We classified the species according to dispersal syndrome and ecological group. Overall, we found 93 species in the adult layer and 70 species in the regenerating layer. The similarity dendrograms based on the two evaluated indices demonstrated the existence of the two initially stratified environments in both strata. The IndVal (%) indicated that the set of indicator species differed between the strata. Thereby, the fragment is in an intermediate stage of successional progression. PCA showed that plots in the wet area had higher pH values and Ca, Zn, and Fe levels, while plots in the dry area did not clearly distinguish, varying in terms of K, B, and organic matter content. In CCA, a set of species that occurred exclusively in the damp area showed a strong relationship with the analyzed variables. The area is a diverse ecosystem that efficiently provides ecosystem services to society and should be the subject of long-term conservation and research.

Association of Root Biofilm Bacteriome with Root Caries Lesion Severity and Activity

Introduction: This research aimed to assess the association of root biofilm bacteriome with root caries lesion severity and activity in institutionalised Colombian elderlies and was conducted to gather data on the root caries bacteriome in this population. Methods: A bacteriome evaluation of biofilm samples from sound and carious root surfaces was performed. Root caries was categorised (ICDAS Root criteria) based on severity (sound surfaces, initial: non-cavitated, moderate/extensive combined: cavitated) and activity status (active and inactive). DNA was extracted and the V4 region of the 16S rRNA gene was sequenced; afterwards the classification of features was conducted employing amplicon sequence variants and taxonomic assignment via the Human Oral Microbiome Database (HOMD). Bacterial richness, diversity (Simpson’s and Shannon’s indices), and relative abundance estimation were assessed and compared based on root caries severity and activity status (including Sound surfaces). Results: A total of 130 biofilm samples were examined: sound (n = 45) and with root caries lesions (n = 85; by severity: initial: n = 41; moderate/extensive: n = 44; by activity: active: n = 60; inactive: n = 25). Species richness was significantly lower in biofilms from moderate/extensive and active groups compared to sound sites. There was a higher relative abundance of species like Lechtotricia wadei, Capnocytophaga granulosa, Cardiobacterium valvarum, Porphyromonas pasteri – in sound sites; Dialister invisus, Streptococcus mutans, Pseudoramibacter alactolyticus and Bacteroidetes (G-5) bacterium 511 – in moderate/extensive lesions, and Fusobacterium nucleatum subsp. animalis, Prevotella denticola, Lactobacillus fermentum, Saccharibacteria (TM7) (G-5)bacterium HMT 356 – in active lesions. Conclusion: Root caries bacteriome exhibited differences in species proportions between the compared groups. Specifically, cavitated caries lesions and active caries lesions showed higher relative abundance of acidogenic bacteria.

Changes in the bird communities of Nothofagus forests in a long‐term plot in Tierra del Fuego

AbstractLong‐term studies have proven to be important to characterize animal communities and analyse the ecological responses to climate and environmental changes. These studies are necessary to determine the natural community variability (e.g., richness and density) to develop better conservation strategies to face climate changes. Here, we analysed the natural changes in the structure and functional traits of bird communities over 13 consecutive years (2010–2022) and determined the number of years of sampling needed to obtain a good estimation of the community structure variables in deciduous high latitude Nothofagus forests. Using point counts, we studied closed (80% of canopy cover) and open (40% of canopy cover) forests inside the Tierra del Fuego National Park. Species richness, density, biomass, and functional traits (migratory status, trophic groups, nest type, and feeding strata) were analysed using generalized linear models with forest type (closed and open) and year (2010–2022) as the main factors, while the standard error (SE) of sampling obtained from one to 12 sampling years was compared. Richness was significantly higher in open forests (p < 0.01), while density and biomass were higher in closed forests. Additionally, density and biomass significantly varied among years in both forest types (e.g., lower density in 2013, 2014 and 2015, and higher in 2019). The density of birds for some functional traits also varied among years and forest types (e.g., higher values of cavity nesters in closed forests during 2019). Five to six years of sampling were needed to have an acceptable estimation of richness (20% SE), between 10 and 12 years for density, and >12 years for biomass. This study highlights the importance of long‐term studies to visualize natural variations in undisturbed habitats along time.

Factors that interfere with the estimation of bat richness in Atlantic Forest, southeastern Brazil

Capture success of bats can be affected not only by local bat density, but also by several methodological aspects. Many factors interfere with the sampling completeness and capture success of bats. Considering the variety of sampling methods used for investigating, the objective of the present study is to analyze different factors that interfere with sampling completeness and species richness estimates of bats. To carry out the present study, we used data from the State of Rio de Janeiro from inventories carried out from 1989 to 2013 by the Laboratory of Bat Diversity and data from the literature until 2023. We analyzed the following parameters: number of sampling nights, period of nocturnal sampling, number of sites where the mist nets were opened, sampling in diurnal roosts, and moon phase. We observed that the localities with more than 30 species recorded had huge sampling efforts. For studies based on a small capture effort, the active search for roosts during the day increases the probability of recording species found mainly in high sampling effort studies. The most complete inventories are those with a sampling effort of at least 24 nights, including sampling in different habitats, such as trails, water bodies, and close to fruiting plants, as well those including search for day roosts and with fieldwork not restricted to a specific moon phase. Mist nets should be set up not only on trails and close to fruiting trees, but also over water bodies to increase the probability of recording insectivorous species.

A meta‐analysis examining how fish biodiversity varies with marine protected area size and age

AbstractMarine protected areas (MPAs) are a well‐established conservation practice worldwide, but their effectiveness in protecting or replenishing fish biodiversity remains uneven. Understanding the patterns of this heterogeneity is central to general guidelines for MPA design and can ultimately provide guidance on how to maximize MPA potential. Here, we examine associations between the degree of protection, duration of protection, and protected area size, with fish biodiversity inside of protected areas relative to that of sites nearby, but outside of protected areas. We quantitatively synthesize 116 published estimates of species richness from 72 MPAs and 38 estimates of Shannon entropy from 21 MPAs. We show that species richness is on average 18% (95% CIs: 10%–29%) higher in protected areas than in areas open to fishing; on average, Shannon entropy is 13% (95% CIs: −2% to 31%) higher within protected areas relative to outside. We find no relationship between the degree and duration of protection with the ratio of species richness inside versus outside of protected areas; both fully and partially protected areas contribute to the accumulation of species inside of protected areas, and protected areas of all ages contribute similarly on average to biodiversity conservation. In contrast to our expectations, increasing protected area size was associated with a decreased ratio of species richness sampled at sites inside versus outside of the protected area, possibly due, for example, to insufficient enforcement and/or low compliance. Finally, we discuss why meta‐analyses such as ours that summarize effect sizes of local scale biodiversity responses, that is, those at a single site, can only give a partial answer to the question of whether larger protected areas harbor more species than comparable unprotected areas.

Species richness pattern of aquatic vascular macrophytes along elevation gradients in Nepal Himalayas

Abstract. Siwakoti EA, Nepali B, Mandal TN, Baniya CB. 2023. Species richness pattern of aquatic vascular macrophytes along elevation gradients in Nepal Himalayas. Biodiversitas 24: 5179-5190. Aquatic vascular macrophytes constitute an important component of aquatic ecosystems. This study aims to determine the species richness pattern of aquatic vascular macrophytes along elevation gradients (100-4900 m asl) in the Nepal Himalayas. We used available published literature on elevational ranges of aquatic vascular macrophytes in Nepal to interpolate the species elevational ranges, thereby providing species richness estimates for 100 m elevational bands. A total of 113 species of aquatic vascular macrophytes belonging to 66 genera under 35 families were recorded from Nepal. Among these macrophytes, dicots were represented by 21 families, monocots with 10 families and pteridophytes with 4 families. Regarding the geographical divisions, the total number of aquatic vascular macrophytes recorded was 76 from the east, 90 from the central and 67 from the west, conclusively central Nepal showed the maximum number of macrophytes. The highest species richness was contributed by Hydrocharitaceae followed by Potamogetonaceae, Plantaginaceae, Lentibulariaceae and Nymphaeaceae. So far, the functional types of macrophytes are concerned, free-floating species were 15, submerged species were 36, floating-leaved species were 18 and emergent species were 44 along elevation gradients in the three geographical divisions in Nepal. The Generalized Linear Model (GLM) was applied to find out the relation between the species richness of aquatic vascular macrophytes with elevation. It showed a statistically significant monotonic declining pattern with increasing elevation. The occurrence of this model was further verified by aquatic vascular macrophyte richness at every 200 m elevation which converged with the general pattern. The study conducted along one of the world’s longest bioclimatic elevational gradients led to support the monotonic declining pattern of aquatic vascular macrophytes richness indicating the difference in richness pattern among aquatic and terrestrial ecosystems. It also emphasizes the importance of conserving aquatic ecosystems with their vegetation.

The Influence of Grazing Systems on Bird Species Richness and Density in the Nebraska Sandhills

Grazing is the de facto method of habitat management used in much of the Nebraska Sandhills. Ranchers use a variety of grazing systems, and our goal was to evaluate the effects of systems on grassland birds. We estimated the species richness and density of grassland birds for three grazing systems used on private ranches: long, medium, and short duration grazing systems. We observed sixty species, and the grazing system with pastures utilizing long duration grazing periods had the highest estimates of species richness as well as the most heterogeneous habitat structure. Differences in species richness among systems were most pronounced in years of limited precipitation. Together, grasshopper sparrows (Ammodramus savannarum), western meadowlarks (Sturnella neglecta), and brown-headed cowbirds (Molothrus ater) accounted for 72% of our observations. We used a model comparison approach to determine the effects of habitat on the densities of six species. Densities of grasshopper sparrows and mourning doves showed effects of the grazing system. More species had higher densities in short duration, rotational systems than other grazing systems. However, species of grassland birds showed responses to a variety of cover types and habitat structures depending on life history needs. Regardless of the grazing system used, managers can use grazing and other tools such as prescribed burning to maintain habitat heterogeneity to support diverse bird communities.

Effects of forest management on private lands in West Virginia on Cerulean Warblers (Setophaga cerulea) and the avian community

The USDA Natural Resources Conservation Service (NRCS) supports private lands conservation projects across the United States to benefit imperiled focal wildlife species using conservation practices to restore habitat. The Cerulean Warbler Appalachian Forestland Enhancement Project (CWAFEP) was initiated in 2015 to help stabilize or reverse Cerulean Warbler population declines by using forest management to create or enhance breeding habitat on private lands in Appalachian focal areas. We evaluated Cerulean Warbler occupancy on CWAFEP sites treated using NRCS conservation practices to inform adaptive management strategies. We also assessed associated forest focal species’ occupancy and species richness of avian guilds to evaluate the effects of conservation practice implementation on the avian community. We conducted point count surveys at 194 locations on 21 private properties enrolled in the CWAFEP in West Virginia during May – July 2019 and 2020. We compared occupancy among four treatments: reference, pre-treatment, 1-year post-treatment, and 2 – 4 years post-treatment sites. To examine how vegetation structure changes among treatments affected occupancy, we also collected and included vegetation variables. Cerulean Warbler occupancy estimates were not different among treatments, suggesting that post-treatment study sites surveyed did not achieve their goal of increasing Cerulean Warbler occupancy. Cerulean Warbler occupancy decreased by 91 % as elevation increased from 200 to 800 m and increased by 397 % as sapling cover increased from 0 to 100 %. Occupancy for three forest focal species (Blue-gray Gnatcatcher, Eastern Wood-pewee, and Scarlet Tanager) and species richness of four avian guilds also were not different among treatments. Thus, Cerulean Warbler occupancy and selected avian community demographics were not related to recent conservation practice implementation in the short-term (1 – 4 years post-treatment), but there are opportunities to improve NRCS conservation practice implementation for more effective Cerulean Warbler conservation. We suspect that the lack of differences in occupancy and species richness estimates was due to site selection related to ecoregion, small treatment areas, and challenges associated with private lands conservation efforts resulting in insufficient reduction in basal area. If NRCS conservation practices implemented through CWAFEP are going to help reverse Cerulean Warbler population declines, CWAFEP sites need to achieve the recommended basal area range of ∼ 9.2 – 20.7 m 2/ha (40 – 90 ft2/ac) during contract implementation. Our conclusions are critical to updating our knowledge for Cerulean Warbler best management practices and informing future regional conservation implementation.

Validating a multi-locus metabarcoding approach for characterizing mixed-pollen samples

BackgroundThe mutualistic interaction between entomophilous plants and pollinators is fundamental to the structure of most terrestrial ecosystems. The sensitive nature of this relationship has been disrupted by anthropogenic modifications to natural landscapes, warranting development of new methods for exploring this trophic interaction. Characterizing the composition of pollen collected by pollinators, e.g. Apis mellifera, is a common means of exploring this relationship, but traditional methods of microscopic pollen assessment are laborious and limited in their scope. The development of pollen metabarcoding as a method of rapidly characterizing the abundance and diversity of pollen within mixed samples presents a new frontier for this type of work, but metabarcoding may have limitations, and validation is warranted before any suite of primers can be confidently used in a research program. We set out to evaluate the utility of an integrative approach, using a set of established primers (ITS2 and rbcL) versus melissopalynological analysis for characterizing 27 mixed-pollen samples from agricultural sites across Canada.ResultsBoth individual markers performed well relative to melissopalynology at the family level with decreases in the strength of correlation and linear model fits at the genus level. Integrating data from both markers together via a multi-locus approach provided the best rank-based correlation between metagenetic and melissopalynological data at both the genus (ρ = 0.659; p < 0.001) and family level (ρ = 0.830; p < 0.001). Species accumulation curves indicated that, after controlling for sampling effort, melissopalynological characterization provides similar or higher species richness estimates than either marker. The higher number of plant species discovered via the metabarcoding approach simply reflects the vastly greater sampling effort in comparison to melissopalynology.ConclusionsPollen metabarcoding performed well at characterizing the composition of mixed pollen samples relative to a traditional melissopalynological approach. Limitations to the quantitative application of this method can be addressed by adopting a multi-locus approach that integrates information from multiple markers.