Communities In Agroecosystems Research Articles

Conservation Agricultural Practices Increase Soil Fungal Diversity and Network Complexity in a 13-Year-Duration Conservation Agriculture System in the Loess Plateau of China

Agricultural practices can affect the diversity and community structure of soil fungi. This study investigates the impact of long-term agricultural practices on soil fungal diversity in the Loess Plateau of northwestern China. Different tillage practices have been implemented for 13 years, and their impact on soil fungi is assessed using high-throughput Illumina Sequencing. This study found a total of 2071 fungal Amplicon Sequence Variants (ASVs), and these were assigned to 25 different phyla, 372 families, and 496 genera. The fungal communities were dominated by Ascomycota (52.1%), followed by Zygomycota (14.3%) and Basidiomycota (9.0%). In general, the soil exhibited higher fungal community abundance, richness, and diversity in winter than in summer. Notably, no-tillage or stubble retention resulted in greater diversity than conventional tillage, with no-tillage combined with stubble retention resulting in the highest fungal richness, diversity, and network complexity in both summer and winter. These findings indicate that no-tillage with stubble retention is beneficial for biological soil components, which favors the establishment of abundant and diverse soil fungal communities in the Loess Plateau of China. The present study expands the knowledge of fungal communities in agro-ecosystems and the long-term ecosystem benefits of tillage practices.

Environmental Factors Affecting Spatio-Temporal Distribution of Crop-Exploiting Species: Implications for Coexistence Between Agricultural Production and Avifauna Conservation in Wetlands

Bird communities in agroecosystems bring both ecosystem services (e.g., pollination) and disservices (e.g., crop exploitation) to farmers. However, in the proximity of wetland reserves, farmers disproportionately experience harvest yield loss due to large aggregation of bird species that can utilize various agricultural resources. This often results in negative human–wildlife interactions which lower conservation support among farmers. Knowledge about the distribution of avian species that negatively influence yields, and its environmental drivers is thus fundamental to reconcile crop production and bird conservation. This study aims to examine the spatio-temporal patterns in richness and abundance of bird species known to cause agricultural yield loss as well as species-specific distribution patterns for the six bird species that are most challenging for local farmers. In combination with interview surveys of local farmers (n = 367) and seasonal bird surveys (n = 720), we investigated distribution of crop-exploiting avian species in the Indawgyi wetland ecosystem in Myanmar. Our results showed high richness and abundance of crop-exploiting species in the water habitat across all seasons, with most challenging species exhibiting higher presence closer to these water sources. The crop phenology had positive effect on species richness and abundance during the growing season. The agricultural use of crop-exploiting species was season- and species-specific, where the presence probability in the agricultural habitat was higher in habitat generalists than wetland specialists. Therefore, we suggest improved management of natural wetland habitats (e.g., habitat restoration), sustainable coexistence mechanisms in farms close to water (e.g., bird-friendly rice farming and Ecolabel certification) to reduce avian impacts on the farming communities and, at the same time, to promote bird conservation in wetlands of international importance.

Climate and land use primarily drive the diversity of multi-taxonomic communities in agroecosystems

To successfully conserve and restore agrobiodiversity, it is essential to understand the impact of multiple drivers and interlinkages across multiple taxa that occur above, across, and below the soil interface. Based on data from six agricultural landscapes in Central Germany, with 16 sampling plots per landscape, we used structural equation models to disentangle the impacts of climate, land-use, and soil factors on the diversity of multiple taxonomic groups. We expected belowground communities (soil bacteria and fungi) to be more driven by soil variables, mobile aboveground groups (wild bees, ground beetles) to be more driven by climate and land use, and vascular plants, that have an above- and belowground component, to respond to a combination of all factors.According to our expectations, climate and land-use variables had an important role in shaping aboveground and plant communities. In contrast to our expectations, soil characteristics were of lesser importance for belowground organisms. Moreover, climatic factors had a strong impact on the soil microbiome, but this effect was indirect, modulated by soil pH. We also found indications for cascading effects of environmental factors via interlinkages within and among the above- and belowground communities. Our results highlight the importance of direct and indirect effects of multiple drivers on the diversity of multiple taxonomic groups and support recent calls for a multifunctional approach for sustainable landscape management and nature restoration, suggesting to focus on the promotion of semi-natural habitats but also considering the climatic context.

Site properties, environmental factors, and crop identify influence soil bacterial communities more than municipal biosolid application

Reducing the environmental impact of Canadian field crop agriculture, including the reliance on conventional synthesised fertilisers, are key societal targets for establishing long-term sustainable practices. Municipal biosolids (MSB) are an abundant, residual organic material, rich in phosphate, nitrogen and other oligo-nutrients, that could be used in conjunction with conventional fertilisers to decrease their use. Though MBS have previously been shown to be an effective fertiliser substitute for different crops, including corn and soybean, there remain key knowledge gaps concerning the impact of MBS on the resident soil bacterial communities in agro-ecosystems. We hypothesised that the MBS fertiliser amendment would not significantly impact the structure or function of the soil bacterial communities, nor contribute to the spread of human pathogenic bacteria, in corn or soybean agricultural systems. In field experiments, fertiliser regimes for both crops were amended with MBS, and compared to corn and soybean plots with standard fertiliser treatments. We repeated this across four different agricultural sites in Quebec, over 2021 and 2022. We sampled MBS-treated, and untreated soils, and identified the composition of the soil bacterial communities via 16S rRNA metabarcoding. We found no indication that the MBS fertiliser amendment altered the structure of the soil bacterial communities, but rather that the soil type and crop identities were the most significant factors in structuring the bacterial communities. Moreover, there was no evidence that the MBS-treated soils were enriched in potential human bacterial pathogens over the two years of our study. Our analysis indicates that not only can MBS function as substitutes for conventional, synthesised fertilisers, but that they also do not disrupt the structure of the resident soil bacterial communities in the short term. Finally, we suggest that the use of MBS in agro-ecosystems poses no greater concern to the public than existing soil bacterial communities. This highlights the significant role MBS could potentially have in reducing the use of conventional industrial fertilisers and improving agricultural production, without risking environmental contamination.

Effects of study design parameters on estimates of bee abundance and richness in agroecosystems: a meta-analysis

Abstract Pollinators are critical for agricultural production and food security, leading to many ongoing surveys of pollinators (especially bees) in crop and adjacent landscapes. These surveys have become increasingly important to better understand the community of potential pollinators, quantify relative insect abundance, and secure crop ecosystem services. However, as some bee populations are declining, there is a need to align and improve bee survey efforts, so that they can best meet research and conservation goals, particularly in light of the logistical and financial constraints of conducting such studies. Here, we mined the existing literature on bee surveys in or around agricultural lands to better understand how sampling methods can be optimized to maximize estimates of 2 key measures of bee communities (abundance and richness). After reviewing 72 papers spanning 20 yr of publication, we found that study duration, number of sites, sampling time, and sampling method most significantly influenced abundance, while the number of trips per year and collection method significantly influenced richness. Our analysis helps to derive thresholds, priorities, and recommendations that can be applied to future studies describing bee communities in agroecosystems.

Long‐term organic farming and floral diversity promotes stability of bee communities in agroecosystems

Abstract Increasing bee diversity promotes pollination services on farms. Yet, given the high turnover in pollinator communities, without knowledge of how pollinator communities assemble, it is difficult to conserve or increase bee diversity. Thus, a mechanistic understanding of factors mediating pollinator community assembly could promote pollinator conservation measures. To assess the determinants of pollinator community assembly and structure, we surveyed bee communities and floral resources on 36 farms ranging from 0 to 43 years in organic production. We used niche‐based and stochastic species abundance models to characterise the mechanisms driving community assembly, and an additive partition of beta diversity to evaluate resource and species turnover (i.e. community structure). We then used statistical models to assess whether resource turnover or time in organic production altered community assembly and beta diversity, and a jackknife analysis to assess the sensitivity of top models to resource and species identity. We show that bee communities on farms that practiced organic methods for longer assembled by niche‐based rather than stochastic processes and had less turnover in bee species across years. Because our model of niche‐based processes assumes resource use, these results indicate bee communities reflect underlying species‐specific resource preferences (e.g. floral and/or nesting resources) and that longer periods of organic management reduced dissimilarity mediated by species replacement. Our jackknife approach then examined the role of species identity effects in beta diversity, showing changes in floral resources increased dissimilarity driven by bee species loss, but only in landscapes simplified by urbanisation. This jackknife analysis then indicated that landscape resource replacement which was not driven by particular landscape classes, mediated bee species replacement wherein dissimilarity was driven by a generalist native bee, suggesting bee life history (e.g. flexibility in resource use) and landscape complementarity, rather than identity, underlie patterns identified using the beta diversity equations. Our results show bee communities assemble by niche‐based processes, evidenced by collinearity in resource and bee species turnover. Because niche‐based assembly indicates ecosystem health, farmers who adopt crop diversification and practice organic methods for longer may promote pollinator diversity and stability leading to improved pollination in farms. Read the free Plain Language Summary for this article on the Journal blog.

Organization of the macroinvertebrate community in a tropical annual agroecosystem into modules.

The structure of macroinvertebrate communities in agroecosystems has been assumed to be modular and organized around key herbivore pests. We characterized the macroinvertebrate community in the annual organic brassica agroecosystem in tropical central Brazil to determine if the community was a random assemblage of independent populations or was organized into repeatable multi-species components. We sampled 36 macroinvertebrate taxa associated with six organic brassica farms at biweekly intervals during the dry season during two years in the Distrito Federal, Brazil. We used an unconstrained ordination based on latent variable modeling (boral) with negative binomial population counts to analyze community composition independent of variation in sample abundance. We evaluated observed community structure by comparing it with randomized alternatives. We found that the community was not a random assemblage and consistently organized itself into two modules based around the major herbivores; one with lepidoptera and whiteflies and their associated natural enemies which was gradually replaced during the season by one with brassica aphids, aphid parasitoids and coccinellids. This analysis suggests that the historical and present-day focus on pest herbivores and their associated species in agroecosystems may be justified based on community structure.

Foliar fungal communities in agroecosystems depend on crop identity and neighboring vegetation

Agricultural intensification causes plant diversity loss and environmental homogenization, which may result in changes to plant-microbiome interactions mediating plant growth and stress tolerance. We hypothesized that foliar fungal microbiomes would depend on plant traits and environmental filters, constrained by neighboring vegetation expected to serve as a fungal source. Thus, we sampled foliar fungi from four crops (three annual and one perennial), four sites per crop, and three varieties per annual crop, across a 500-km expanse in North Carolina, USA and tested the role of host traits, environmental traits, and vegetative landcover on foliar fungal community structure. Crop species and site were major determinants of community structure, primarily due to differences in plant size and growing season. Site consistently explained 10× more variation in community structure than host variety across the annual crops. Finally, reduced natural vegetative cover surrounding farms was correlated with decreased fungal richness and more homogeneous microbiome assembly. Based on these results, we posit that foliar fungal assembly in crops results from host and environmental filters acting on inputs from the nearby vegetation. Future efforts at agricultural microbiome management must therefore consider landscape management and will require an improved understanding of how agricultural intensification alters microbial source pools.

Arable plant communities as a surrogate of crop rhizosphere microbiota

Soil microbiota is a crucial component of agroecosystem biodiversity, enhancing plant growth and providing important services in agriculture. However, its characterization is demanding and relatively expensive. In this study, we evaluated whether arable plant communities can be used as a surrogate of bacterial and fungal communities of the rhizosphere of Elephant Garlic (Allium ampeloprasum L.), a traditional crop plant of central Italy. We sampled plant, bacterial, and fungal communities, i.e., the groups of such organisms co-existing in space and time, in 24 plots located in eight fields and four farms. At the plot level, no correlations in species richness emerged, while the composition of plant communities was correlated with that of both bacterial and fungal communities. As regards plants and bacteria, such correlation was mainly driven by similar responses to geographic and environmental factors, while fungal communities seemed to be correlated in species composition with both plants and bacteria due to biotic interactions. All the correlations in species composition were unaffected by the number of fertilizer and herbicide applications, i.e., agricultural intensity. Besides correlations, we detected a predictive relationship of plant community composition towards fungal community composition. Our results highlight the potential of arable plant communities to be used as a surrogate of crop rhizosphere microbial communities in agroecosystems.

Soil depth and geographic distance modulate bacterial β-diversity in deep soil profiles throughout the U.S. Corn Belt.

Understanding how microbial communities are shaped across spatial dimensions is of fundamental importance in microbial ecology. However, most studies on soil biogeography have focused on the topsoil microbiome, while the factors driving the subsoil microbiome distribution are largely unknown. Here we used 16S rRNA amplicon sequencing to analyse the factors underlying the bacterial β-diversity along vertical (0-240 cm of soil depth) and horizontal spatial dimensions (~500,000 km2 ) in the U.S. Corn Belt. With these data we tested whether the horizontal or vertical spatial variation had stronger impacts on the taxonomic (Bray-Curtis) and phylogenetic (weighted Unifrac) β-diversity. Additionally, we assessed whether the distance-decay (horizontal dimension) was greater in the topsoil (0-30 cm) or subsoil (in each 30 cm layer from 30-240 cm) using Mantel tests. The influence of geographic distance versus edaphic variables on the bacterial communities from the different soil layers was also compared. Results indicated that the phylogenetic β-diversity was impacted more by soil depth, while the taxonomic β-diversity changed more between geographic locations. The distance-decay was lower in the topsoil than in all subsoil layers analysed. Moreover, some subsoil layers were influenced more by geographic distance than any edaphic variable, including pH. Although different factors affected the topsoil and subsoil biogeography, niche-based models explained the community assembly of all soil layers. This comprehensive study contributed to elucidating important aspects of soil bacterial biogeography including the major impact of soil depth on the phylogenetic β-diversity, and the greater influence of geographic distance on subsoil than on topsoil bacterial communities in agroecosystems.

The contrasting response of cavity‐nesting bees, wasps and their natural enemies to biodiversity conservation measures

Abstract The implementation of agri‐environmental schemes (AES) is a major tool to sustain biodiversity and ecosystem services in European agricultural landscapes. The benefit of different types and features of novel biodiversity measures needs to be assessed in order to successfully conserve insect communities in agroecosystems. We set up trap nests in 3 × 3 km landscapes in Germany, in which farmers implemented different novel biodiversity measures. We tested the effect of different features of the closest three biodiversity measures (i.e. distance to measures, measures' area, measures' quality) and of the proximity to forest and oilseed rape and of landscape connectivity on the abundance and species richness of cavity‐nesting bees, wasps and their natural enemies. We found total cavity‐nesting insect abundances to increase with measures' quality and to decline with increasing distance to oilseed rape and forest. Parasitism and mortality rates declined with edge density. Cavity‐nesting bees were not affected by biodiversity measures. Total wasp and herbivore‐predating wasp abundances increased in proximity to biodiversity measures. The abundance and species richness of all wasps, natural enemies and spider‐predating wasps declined with increasing distance to forest. Cavity‐nesting wasps benefit from biodiversity measures, while effects on solitary bees might only be detectable after several years after measure establishment. The proximity to forest is a major factor promoting insects as forest edges provide food, nesting sites and shelter. We emphasise the need for long‐term insect monitoring and an increasing focus of future AES on the creation of nesting habitats for effective insect conservation.

Diversity and abundance of bacterial and fungal communities in rhizospheric soil from smallholder banana producing agroecosystems in Kenya

In agroecosystems, microbial communities play a crucial role in delivery of various ecosystem services. These microbial communities are affected by several factors such as soil physicochemical properties which contribute to the diversity of bacterial and fungal communities. In this study, we investigated the soil physicochemical parameters and the diversity and abundance of bacterial and fungal communities in rhizospheric soil collected from banana growing regions in Kisii, Nyamira and Embu Counties of Kenya. Rhizospheric soil samples from the three regions showed significant differences at (P= 0.01) with the lowest recorded pH being 4.43 in Embu County. Based on Next-generation sequencing results, there was a significant diversity and abundance of bacterial division Proteobacteria while the predominant fungal division was basidiomycota, Several genera in the fungal division such as Penicillium and Cladosporium as well as bacterial genera such as Acidobacterium and Pseudomonas sp. were those associated with soil. There were several plant pathogenic and beneficial bacteria and fungi. Based on redundancy analysis (RDA) the distribution of these microbes was affected negatively by soil parameters such as total organic carbon (TOC) and pH. In conclusion, Soil health and continuous mono-cropping systems play a significant role in the diversity and abundance of both beneficial and harmful soil microbes. Metagenomics approaches in studying microbial communities in agroecosystems is a revolutionary approach which will aid in the development of sustainable tools in agriculture that improve microbiome structures as well as overall productivity.

Soil Microbial Communities Involved in Proteolysis and Sulfate-Ester Hydrolysis Are More Influenced by Interannual Variability than by Crop Sequence

Proteases, catalysing protein hydrolysis, and arylsulfatases, catalysing sulfate-ester hydrolysis, are key microbial enzymes for N and S mineralization in soil. However, knowledge gaps remain regarding the effect of crop successions and seasonal and interannual meteorological variations on microbial communities responsible for those activities. Here, we compared the effect of six cropping sequences on the abundance and activity of microbial communities involved in proteolysis and sulfate-ester hydrolysis in northern France over four years, with two sampling dates per year. Crop sequences impacted soil microbial communities involved in proteolysis but not those involved in sulfate-ester hydrolysis. Oilseed rape following wheat presented a higher abundance of fungal 18S rDNA, culturable bacteria and alkaline metalloprotease genes and higher protease activity than other crop sequences (wheat following oilseed rape or pea, barley following wheat and pea following barley). Net N and S mineralization was not impacted by the cropping sequence. However, interannual variability of microbial parameters was large, and largely overcame the effect of crop sequences. Precipitation variability between years was the likely cause of this effect. In conclusion, the interaction between current crop, previous crops and yearly meteorology can strongly impact the soil microbial communities in agroecosystems.

“Strawberry fields forever”: flower-inhabiting thrips (Thysanoptera: Thripidae) communities and their spatial interactions in strawberry agroecosystems in Québec, Canada, with first mention of pest Frankliniella intonsa (Trybom)

Abstract Thrips (Thysanoptera: Thripidae) communities in agroecosystems are poorly known, particularly in Québec, Canada, where thrips can cause damage in strawberry crops. The phenology of anthophagous thrips and their use of cultivated and wildflower resources were monitored in strawberry agroecosystems, encompassing strawberry (Rosaceae) fields and adjacent uncultivated margins, on Orléans Island, Québec, Canada. A community comprised of 11 thrips species was described, dominated during the whole season by pest species Frankliniella tritici and F. intonsa, which is a first mention in Eastern Canada. Surprisingly, the major strawberry pest F. occidentalis was absent in our samples. Thrips species richness and abundance on wildflowers varied, with few flowering plant species supporting a majority of the community. Sampling sites and local wildflower presence influenced the thrips species assemblage observed on strawberry crops. Such a high thrips diversity was unexpected in this agroecosystem. The identified associations between pest thrips and wildflower species will be useful to develop better control programmes in strawberry crops.

SOC mediates the contribution of generalists and specialists to changes in soil nirK bacterial diversity: Evidence from apple orchards in main production areas of China

nirK-Denitrifying bacteria are closely related to N2O emissions and they have been studied widely in agro-ecosystems. However, the mechanisms associated with maintenance of the diversity of nirK bacterial communities in agro-ecosystems are unclear. In particular, the ecological roles of “generalists” and “specialists” in nirK bacterial communities under different soil organic carbon (SOC) levels have not been characterized. In this study, we divided 102 soil samples (0–20 and 20–40 cm) from 62 apple orchards in China's main apple producing areas (Shaanxi and Shandong provinces) into four groups according to the SOC content and soil depth, i.e., high organic carbon soils in the 0–20 cm depth, low organic carbon soils in the 0–20 cm depth, high organic carbon soils in the 20–40 cm depth, and low organic carbon soils in the 20–40 cm depth. In the nirK bacterial community, 4187 operational taxonomic units (OTUs) (∼51.32 %) were classified as specialists and 1781 OTUs (∼21.83 %) as generalists. The α-diversity of generalists was higher in the high SOC soils than the low SOC soils, which was consistent with the α-diversity of the whole nirK bacterial community. However, the observed number of specialist species was lower in high SOC soils than low SOC soils. Analysis based on the Spearman's correlation coefficients also showed that the α-diversity and relative abundances of generalists and specialists responded differently to environmental factors. Both deterministic and stochastic processes contributed to the assembly of generalists and specialists. Among the deterministic processes, variable selection was important for the assembly of the generalist community, whereas homogeneous selection was important for the assembly of the specialist community. The niche breadth of generalists was higher than that of specialists, whereas the niche overlap of specialists was higher than that of generalists. The niche breadth of generalists was higher in high SOC soils than low SOC soils. In both networks, generalists had higher degrees than specialists, although the number of generalists was much lower than that of specialists. Our findings demonstrate the contributions of generalists and specialists to the changes in the diversity of the nirK bacterial community at different SOC levels as well as providing new insights into the mechanisms responsible for maintaining the diversity of the nirK bacterial community.

Maize varieties and their root trait variation mediate the development of rhizosphere arthropod diversity

While ecological roles of rhizosphere arthropods are well documented, little is known about the relationship between the development of plant roots and soil arthropod communities in agroecosystems. In this study, we investigated the effects of maize varieties and their root traits on the diversity and community composition of soil arthropods over time. Soil arthropods and root traits were evaluated before planting and at 30 and 60 days after planting in four maize varieties with different root growth angles and lateral root branching. Arthropod diversity declined from day 0 to 30 but recovered by day 60 with the development of maize roots. Two maize varieties (Nei 542018 and Nei 542022) exhibited lower brace and crown root angles, and arthropod taxon richness was greater in these two varieties than in others. The highest abundance of detritivores and predators was found in one of the maize varieties (Nei 542018) which, in addition to lower root angle, attained greater root diameter and lateral root branching and length. Redundancy analysis indicated that soil arthropod composition was correlated with crown root angle. Our findings highlight the importance of root traits, especially the angle of the roots, to enhance arthropod biodiversity in the rhizosphere ecosystem.

Analysis of complex trophic networks reveals the signature of land-use intensification on soil communities in agroecosystems

Increasing evidence suggests that agricultural intensification is a threat to many groups of soil biota, but how the impacts of land-use intensity on soil organisms translate into changes in comprehensive soil interaction networks remains unclear. Here for the first time, we use environmental DNA to examine total soil multi-trophic diversity and food web structure for temperate agroecosystems along a gradient of land-use intensity. We tested for response patterns in key properties of the soil food webs in sixteen fields ranging from arable crops to grazed permanent grasslands as part of a long-term management experiment. We found that agricultural intensification drives reductions in trophic group diversity, although taxa richness remained unchanged. Intensification generally reduced the complexity and connectance of soil interaction networks and induced consistent changes in energy pathways, but the magnitude of management-induced changes depended on the variable considered. Average path length (an indicator of food web redundancy and resilience) did not respond to our management intensity gradient. Moreover, turnover of network structure showed little response to increasing management intensity. Our data demonstrates the importance of considering different facets of trophic networks for a clearer understanding of agriculture-biodiversity relationships, with implications for nature-based solutions and sustainable agriculture.

Distribution of earthworm communities in agroecosystems with forested riparian buffer strips: A multiscale study

Knowledge is lacking on the factors controlling the structure and spatial distribution of earthworm communities within agroecosystems. We first hypothesized that forested riparian buffer strips (FRBS) within agricultural landscapes would be a refuge for earthworms, as we predicted higher soil moisture and organic matter inputs in FRBS than in adjacent agricultural fields (treatments = FRBS vs. Field). We further hypothesized that earthworms would be most abundant where the chemical quality of above- and belowground plant litter is high, or where soil disturbance is low. We conducted a field survey to quantify earthworm species abundances in FRBS and adjacent agricultural fields in two bioregions, namely Eastern Canada and Central Europe. At each of 77 sites, we collected and identified earthworms from three plots within FRBS and within adjacent agricultural fields. In each plot, we identified the tree species, understory vegetation, soil drainage class, agricultural crop as well as five soil physicochemical properties. In each bioregion and treatment, we found proportionately more endogeic than anecic or epigeic earthworm species. In Eastern Canada, there were proportionately fewer anecic and more epigeic individuals in FRBS than in fields; in Central Europe there were fewer endogeic and more anecic earthworms in FRBS than in fields. We found significant bioregion × treatment interactions on earthworm abundance and soil moisture. More specifically, in Eastern Canada we found higher earthworm abundance and soil moisture in FRBS, whereas in Central Europe we found higher earthworm abundance in fields and no treatment effect on soil moisture. In both bioregions, we found higher organic matter in FRBS than in fields. In Eastern Canada, earthworm abundance in deciduous and mixedwood stands were higher than in coniferous stands; in Central Europe, earthworm abundance was highest in deciduous stands only. Within FRBS in Eastern Canada, the abundance of the prominent endogeic species, Apporectodea rosea, was correlated with herbaceous plants, notably ferns and graminoids. Conditional regression tree analysis revealed positive relationships between earthworms and soil clay content, pH, moisture and organic matter. Our results suggest that local and landscape patterns in earthworm diversity can be predicted by soil and vegetation attributes, however the relative importance of these factors changes across continental scales due to differences in precipitation patterns and soil moisture availability. Comparing the distributions of earthworms across different scales provides insights into the potential of different species to spread into new habitats with climate change.

Landscape Structure Is a Major Driver of Bee Functional Diversity in Crops

Land-use change is having a negative effect on pollinator communities, and these changes in community structure may have unexpected impacts on the functional composition of those communities. Such changes in functional composition may impact the capacity of these assemblages to deliver pollination services, affecting the reproduction of native and wild plants. However, elucidating those relationships requires studies in multiple spatial scales because effects and consequences are different considering biological groups and interactions. In that sense, by using a multi-trait approach, we evaluated whether the landscape structure and/or local environmental characteristics could explain the functional richness, divergence, and dispersion of bee communities in agroecosystems. In addition, we investigated to what extent this approach helps to predict effects on pollination services. This study was conducted in an agroecosystem situated in the Chapada Diamantina region, State of Bahia, Brazil. Bees were collected using two complementary techniques in 27 sample units. They were classified according to their response traits (e.g., body size, nesting location) and effect traits (e.g., means of pollen transportation, specialty in obtaining resources). The Akaike information criterion was used to select the best models created through the additive combination of landscape descriptors (landscape diversity, mean patch shape, and local vegetation structure) at the local, proximal, and broad landscape levels. Our results indicate that both landscape heterogeneity and configuration matter in explaining the three properties of bee functional diversity. We indicate that functional diversity is positively correlated with compositional and configurational heterogeneity. These results suggest that landscape and local scale management to promote functional diversity in pollinator communities may be an effective mechanism for supporting increased pollination services.

Contrasting beta diversity of spiders, carabids, and ants at local and regional scales in a black soil region, northeast China

Understanding the factors determining the formation of each community and metacommunity across a landscape is one of the most important ideas in soil animal ecology. However, the variables and parameters that shape soil arthropod communities in agroecosystems have not been resolved. These arthropods can serve as important bioindicators of field management and its sustainability. We sampled five corn plantations in each of three locations across a region spanning 600 km to come up with these determinants of the community structure of ground-dwelling spiders (Erigoninae: Araneae), carabids (Coleoptera: Carabidae), and ants (Hymenoptera: Formicidae). The analysis of the five fields within each of the three locations represent our local-scale samples, while the comparisons of the 15 sites across all three locations represent the regional scale samples. We tested the hypothesis that in the models we sampled, environmental/soil variables would drive community assembly locally (within location comparisons), but at the regional scale (between location comparisons), climatic and spatial variables would drive metacommunity assembly. The outcomes of our study showed distinct communities at each of the three locations when compared across regions but locally, fields were similar in species composition, as expected. Locally, spatial variables were important but not soil variables, regulated species richness and abundance. Turnover contributed more than nestedness to explain the biodiversity of spiders, carabids, and ants at both the local and regional scales. Neither purely climate variables, nor purely soil or spatial variables were significant enough explanations for the regional scale arthropod community composition. However, spatially structured environmental factors contributed most to explain the patterns supporting our hypothesis. We conclude that biodiversity in this agroecosystem area can be promoted by a mosaic of land uses being encouraged to increase landscape complexity at the regional scale.