Terrestrial Arthropod Communities Research Articles

Terrestrial arthropods diversity in the Argan Biosphere Reserve: Seasonal dynamics and ecological function roles

Diversity, spatial patterns and temporal trends of terrestrial arthropod communities in the Arganeraie Biosphere Reserve of Morocco are poorly understood. Arthropods were seasonally sampled using pitfall traps at four sites, three of which are Argan forest ecosystem and one of which is a modern Argan grove. Diversity parameters were seasonally measured. Observation allowed identification of 161 morphospecies belonging to the five classes Chilopoda, Malacostraca, Collembola, Insecta and Arachnida were recorded. Captures were dominated by insects, representing more than 90% of the total trapped individuals. Insecta were the most diversified class (122 morphospecies), followed by Arachnida (33). The three other classes were less diversified with two species each. Among insects, Coleoptera and Hymenoptera were the most diversified groups. Diversity parameters exhibited seasonal variations. The highest arthropod abundance per sample was recorded during spring, while observed richness was higher in spring and summer. Shannon diversity index showed no significant difference among seasons. The composition of terrestrial arthropod communities between sites changed among seasons. A high dissimilarity was reported between the terrestrial arthropod community of Belfaa and those of other sites. The classification of arthropods into trophic guilds shows the importance of both predators and detritivores, which shows a higher abundance in spring and summer. Overall, predators guild richness was higher than others among seasons. This study highlights spatiotemporal diversity composition and structure of terrestrial arthropods community associated with the Argan ecosystem, complementing the unique diversity and proliferation of ecotypes present in Morocco.

Variation in Terrestrial Arthropod Communities Across Seasons and Differently Planted Infiltration Basins

Variation in Terrestrial Arthropod Communities Across Seasons and Differently Planted Infiltration Basins

Rainforest conversion to rubber and oil palm reduces abundance, biomass and diversity of canopy spiders.

Rainforest canopies, home to one of the most complex and diverse terrestrial arthropod communities, are threatened by conversion of rainforest into agricultural production systems. However, little is known about how predatory arthropod communities respond to such conversion. To address this, we compared canopy spider (Araneae) communities from lowland rainforest with those from three agricultural systems in Jambi Province, Sumatra, Indonesia, i.e., jungle rubber (rubber agroforest) and monoculture plantations of rubber and oil palm. Using canopy fogging, we collected 10,676 spider specimens belonging to 36 families and 445 morphospecies. The four most abundant families (Salticidae N = 2,043, Oonopidae N = 1,878, Theridiidae N = 1,533 and Clubionidae N = 1,188) together comprised 62.2% of total individuals, while the four most speciose families, Salticidae (S = 87), Theridiidae (S = 83), Araneidae (S = 48) and Thomisidae (S = 39), contained 57.8% of all morphospecies identified. In lowland rainforest, average abundance, biomass and species richness of canopy spiders was at least twice as high as in rubber or oil palm plantations, with jungle rubber showing similar abundances as rainforest, and intermediate biomass and richness. Community composition of spiders was similar in rainforest and jungle rubber, but differed from rubber and oil palm, which also differed from each other. Canonical Correspondence Analysis showed that canopy openness, aboveground tree biomass and tree density together explained 18.2% of the variation in spider communities at family level. On a morphospecies level, vascular plant species richness and tree density significantly affected the community composition but explained only 6.8% of the variance. While abundance, biomass and diversity of spiders declined strongly with the conversion of rainforest into monoculture plantations of rubber and oil palm, we also found that a large proportion of the rainforest spider community can thrive in extensive agroforestry systems such as jungle rubber. Despite being very different from rainforest, the canopy spider communities in rubber and oil palm plantations may still play a vital role in the biological control of canopy herbivore species, thus contributing important ecosystem services. The components of tree and palm canopy structure identified as major determinants of canopy spider communities may aid in decision-making processes toward establishing cash-crop plantation management systems which foster herbivore control by spiders.

Subtle structures with not-so-subtle functions: A data set of arthropod constructs and their host plants.

The construction of shelters on plants by arthropods might influence other organisms via changes in colonization, community richness, species composition, and functionality. Arthropods, including beetles, caterpillars, sawflies, spiders, and wasps often interact with host plants via the construction of shelters, building a variety of structures such as leaf ties, tents, rolls, and bags; leaf and stem galls, and hollowed out stems. Such constructs might have both an adaptive value in terms of protection (i.e., serve as shelters) but may also exert a strong influence on terrestrial community diversity in the engineered and neighboring hosts via colonization by secondary occupants. Although different traits of the host plant (e.g., physical, chemical, and architectural features) may affect the potential for ecosystem engineering by insects, such effects have been, to a certain degree, overlooked. Further analyses of how plant traits affect the occurrence of shelters may therefore enrich our understanding of the organizing principles of plant-based communities. This data set includes more than 1000 unique records of ecosystem engineering by arthropods, in the form of structures built on plants. All records have been published in the literature, and span both natural structures (91% of the records) and structures artificially created by researchers (9% of the records). The data were gathered between 1932 and 2021, across more than 50 countries and several ecosystems, ranging from polar to tropical zones. In addition to data on host plants and engineers, we aggregated data on the type of constructs and the identity of inquilines using these structures. This data set highlights the importance of these subtle structures for the organization of terrestrial arthropod communities, enabling hypotheses testing in ecological studies addressing ecosystem engineering and facilitation mediated by constructs. There are no copyright restrictions and please cite this paper when using the data in publications.

Water-seeking behavior among terrestrial arthropods and mollusks in a cool mesic region: Spatial and temporal patterns.

Dehydration can have negative effects on animal physiological performance, growth, reproduction, and survival, and most animals seek to minimize these effects by reducing water losses or seeking water sources. Much—but not all—of the research on animal water balance comes from dryland ecosystems. However, animals inhabiting mesic regions may also experience desiccating conditions, for example within urban heat islands or during heatwaves and droughts. Here we examined how spatial variation in impervious surface and spatial and temporal variation in microclimate impact water demand behavior of terrestrial arthropods and mollusks in three areas of mesic Northwest Ohio, with analysis of taxa that exhibited the greatest water demand behavior. Water demand behavior was measured as the frequency that individuals were observed at an artificial water source (a moistened pouch), relative to the frequency at a control (a dry pouch). Overall, terrestrial arthropods and mollusks were found about twice as often at the water source than at the control (equivalent to 86 more observations on the wet pouch than on dry at each site, on average), with ants accounting for over 50% of the overall response in urban areas. Daily fluctuations in vapor pressure deficit (VPD) best predicted daily variation in water demand behavior, with increased demand at higher VPD. Mean VPD was generally highest near urbanized areas, but effects of VPD on water demand behavior were generally lower in urbanized areas (possibly related to reductions in overall abundance reducing the potential response). On certain days, VPD was high in natural areas and greenspaces, and this coincided with the highest arthropod water demand behavior observed. Our results suggest that terrestrial arthropod communities do experience periods of water demand within mesic regions, including in greenspaces outside cities, where they appear to respond strongly to short periods of dry conditions—an observation with potential relevance for understanding the effects of climate change.

How soil abiotic factors affect the population fluctuation of Leitneria pugio (Acari: Mesostigmata: Halolaelapidae)

Abiotic factors, such as temperature, humidity, soil elements, along with biotic factors affect terrestrial arthropod communities. Since the application of agricultural fertilizers with the entrance of different elements causes changes in the soil physicochemical conditions, fertilizers may cause fluctuation in the population density of edaphic arthropods. Given this opinion, in this research, the effect of common fertilizers on the population fluctuation and distribution pattern of the predatory mite Leitneria pugio (Karg) was investigated. The experimental treatments were granular urea fertilizer with two doses (200 and 400 kg per ha), poultry manure, zinc sludge (to simulate the accumulation of zinc sulfate fertilizer in the soil), and control in five blocks. Humidity, pH, temperature, NO3– and NO2–, and elements (organic Carbon, K, Na, P, Fe, Cu, Pb, Cr, Cd, Ni, Zn, and As) of soil were measured, and their relationship with the predatory mite population was determined by Pearson correlation coefficient. Iwao's patchiness, Taylor's power law, and Morisita's coefficient of dispersion were used for determining the spatial distribution pattern of L. pugio. The spatial pattern of L. pugio was aggregated, and the highest population density of the predator was observed in December in zinc sludge and control treatments, and in May, in zinc sludge treatment, on the average 60, 35, and 110 per m2, respectively. The relationship between mite's population and Cu and Pb was significantly positive, and L. pugio had a significantly negative relationship with P, NO3– and soil temperature. Nevertheless, the application of different fertilizers did not affect the spatial distribution pattern of the predator.

Fly on the Wall: Comparing Arthropod Communities between Islands with and without House Mice (Mus musculus)1

Invertebrates are key to island ecosystems but impacts from invasive mammalian predators are not well documented or understood. Given this knowledge gap, we studied terrestrial arthropod communities in the presence of a common invasive rodent (house mice, Mus musculus) on a subtropical atoll—Midway Atoll National Wildlife Refuge (MANWR). Here, invasive mice recently began to attack and depredate nesting seabirds, prompting planning for a future mouse eradication. However, uncertainty remains regarding the ecosystem's response to mouse removal. As part of a pre-eradication investigation, we conducted a baseline survey of MANWR's arthropod community structure and diversity (at order level), comparing islands with and without mice. From April 2018 to February 2020, we used pitfall traps to monitor ground-dwelling arthropods on MANWR's Sand Island (mice present) and Eastern Island (mice absent). During our study, we captured over 450,000 specimens from 24 taxonomic units. Arthropods on MANWR form six community clusters and differ between islands and habitats. Richness is relatively similar among clusters and islands, but diversity of common and dominant arthropod taxa is significantly higher on Sand Island, as well as in anthropogenically-built habitats. Weather is not a strong environmental driver of arthropod communities; community structure and diversity vary only slightly throughout the year. Additionally, anthropomorphic landscape-level alteration of MANWR may still influence arthropod communities today. Continued monitoring and research will provide better insight into how arthropod communities recover following invasive mouse eradications. Our study contributes to the body of knowledge of arthropods in the Northwestern Hawaiian Islands, arthropod community ecology, and potential mouse impacts on islands.

Legacy of pre-eruption vegetation affects ground-dwelling arthropod communities after different types of volcanic disturbance.

Volcanic eruptions are one of the largest natural disturbances and are followed by the establishment of novel plant and animal communities in terrestrial ecosystems. However, the role of pre‐eruption vegetation in the establishment of arthropod communities after volcanic disturbances is currently unknown. Here, we asked whether the legacy of pre‐eruption vegetation mediates the community structure of ground‐dwelling arthropods after volcanic disturbances. The 2015 eruption in Kuchinoerabu‐jima Island, southwest Japan, caused two types of disturbances [a pyroclastic flow and a lahar (i.e., mudflow)] in three types of forests (broad‐leaved, black pine, and cedar). We hypothesized that pre‐eruption vegetation would influence the community structure of ground‐dwelling arthropods after the disturbance, and we expected that these effects from vegetation would be more prevalent for the less severe disturbances. The total abundance of ground‐dwelling arthropods decreased more in the lahar than the pyroclastic flow, and arthropod species composition showed a greater change after the lahar. These findings suggest that the lahar disturbance was more severe than the pyroclastic disturbance. Contrary to expectations, the difference in the arthropod species composition among the vegetation types was greatest after the lahar. After the pyroclastic flow, leaf litter remained to some degree with all the vegetation types. After the lahar disturbance, however, although the litter in the cedar forests remained, the litter disappeared completely from broad‐leaved and black pine forests. The disappearance of litter from these two forest types after the lahar may be responsible for the greater difference in arthropod species composition among the vegetation types. This study shows that the legacy effects of pre‐eruption vegetation on terrestrial arthropod communities after volcanic disturbance were different depending on the type of disturbance. Focusing on the role of pre‐eruption biotic factors would contribute to a better understanding of the recovery processes of terrestrial ecosystems after large natural disturbances.

Effects of Malaise trap spacing on species richness and composition of terrestrial arthropod bulk samples

The Malaise trap is a popular device for assessing diverse terrestrial arthropod communities because it collects large samples with modest effort. A number of factors influence its collection efficiency, placement being one of them. For instance, when designing larger biotic surveys using arrays of Malaise traps we need to know the optimal distance between individual traps that maximises observable species richness and community composition. We examined the influence of spacing between Malaise traps by metabarcoding samples from two field experiments at a site in Waterloo, Ontario, Canada. For one experiment, we used two trap pairs deployed at weekly increasing distances (3 m increments from 3 to 30 m). The second experiment involved a total of 10 traps set up in a row at 3 m distance intervals for three consecutive weeks. Results show that community similarity of samples decreases over distance between traps. The amount of species shared between trap pairs drops considerably at about 18 m trap-to-trap distance. This change can be observed across all major taxonomic groups and for two different habitat types (grassland and forest). Large numbers of OTUs found only once within samples cause rather large dissimilarity between distance pairs even at close proximity. This could be caused by a large number of transient species from adjacent habitats which arrive at the trap through passive transport, as well as capture of rare taxa, which end up in different traps by chance.

Contribution to the knowledge of the arthropods community inhabiting the winter-flooded meadows (marcite) of northern Italy.

BackgroundFlooded semi-natural grasslands are endangered ecosystems throughout Europe. In Italy, amongst flooded meadows, one special type called “marcita” is strongly threatened. It is a stable flooded grassland used to produce green forage even during winter months due to the thermal properties of water coming from springs and fountains that prevent the soil from freezing. To date, some research has been carried out to investigate the role of the marcita for ornithological and herpetological communities. However, no comprehensive data on invertebrates inhabiting this particular biotope available. The aim of this study was to characterise the terrestrial entomological community of these typical winter-flooded meadows in northern Italy and, in particular, in six marcita fields located in the Ticino Valley Regional Park. We collected data on species richness and diversity of Carabidae, Staphylinidae, Araneae, Lepidoptera and Orthoptera inhabiting marcita during the summers of 2014 and 2015 and data on overwintering Coleoptera during the winter of 2014-2015. Amongst the collected species, we identified those highly linked to this habitat.New informationWe found a total of 47 ground beetle species, 35 rove beetle species, 29 spider species, one Lucanidae, 16 butterfly species and 24 grasshopper and cricket species. Most of the species were collected during the summers of 2014 and 2015, while some others were also, or exclusively, overwintering (17 ground beetles, four rove beetles and one Lucanidae) and were collected during the winter of 2014-2015.Marcita fields hosted specialised species and species typical of hygrophilous habitats, amongst which are included the butterfly Lycaena dispar, the ground beetle Dolichus halensis and the grasshopper Chrysochraon dispar. This study represents the first contribution to the knowledge of terrestrial arthropod communities associated with this particular type of winter-irrigated meadow in Europe and confirms the importance of this biotope for invertebrate conservation in agricultural landscapes.

Exploring trophic effects of spotted knapweed (Centaurea stoebe L.) on arthropod diversity using DNA metabarcoding

Biological invasions are of particular concern in grasslands, as these systems are highly susceptible to changes in ecosystem energy flows following invasions by exotic plants. Spotted knapweed (Centaurea stoebe L.), a Eurasian, perennial forb, is considered one of the most ecologically harmful invasive plants in North American grasslands and may lead to changes in trophic dynamics, particularly within arthropod communities, which depend on plants for food and habitat. Using DNA metabarcoding to assess community dynamics of arthropods collected from pitfall traps and sweep nets, we explored the effects of C. stoebe density on the alpha, beta and functional diversity of arthropods in a semi-arid grassland in British Columbia, Canada. We used trait-based approaches to investigate the functional responses of terrestrial arthropod communities to better understand the effects of C. stoebe on trophic dynamics. Our study found seasonal differences in the beta-diversity of arthropods, but no differences in arthropod alpha-diversity in knapweed populations. However, our study found a significant reduction in detritivore relative abundance coupled with increases in predator relative abundance, indicating that knapweed density altered the detrital food web. Conversely, herbivores were unaffected by knapweed density, suggesting evidence for greater stability of the grazing food web. Further, predator:prey ratios were highest under high knapweed density. These ratios suggest that top-down effects are likely stronger than the bottom-up effects of C. stoebe invasion. DNA metabarcoding provides the tools to develop detailed surveys of species diversity across a range of environments and trophic levels, which could be a useful guide for planning restoration.

Negative effects of urbanization on terrestrial arthropod communities: A meta‐analysis

AbstractAimUrbanization is one of the most significant anthropogenic alterations of the surface of the Earth and constitutes a major threat to biodiversity at the global level. Arthropods are a very diverse group of organisms, with many species that provide essential ecosystem services. However, their response to urbanization is still unclear. Here, we describe the first meta‐analysis to evaluate the overall effects of urbanization on terrestrial arthropod communities and driving factors related to cities, arthropods and methods.LocationGlobal.Time period1979–2019.Major taxa studiedArthropods.MethodsWe compiled a dataset of 162 publications that have evaluated the effects of urbanization along rural–urban gradients, which yielded 196 observations for diversity and 148 for abundance of arthropods. Moderator variables related to cities (climatic region, size, age, air pollution level and vegetation cover), arthropods (taxonomic and functional group and mobility level) and methods (study duration and type of gradient) were considered. We analysed the data through a hierarchical meta‐analysis that allowed us to take into account the dependence of multiple effect sizes obtained from one study.ResultsOverall, urbanization had a negative effect on the diversity and abundance of terrestrial arthropods. The magnitude of the changes in diversity and abundance along the urban gradient depended on the arthropod taxonomic group. Coleoptera and Lepidoptera were the most affected groups, suggesting that not all species respond in the same way to urbanization. In addition, the age of the cities had a slightly negative influence, but only on abundance.Main conclusionsOur results indicate that terrestrial arthropod communities are less diverse and abundant in more urbanized landscapes. Considering the current biodiversity crisis and the fact that urbanization is one of the most extreme forms of global environmental change, the evidence presented here could be useful to support and direct new conservation efforts in urban habitats.

Comparative analysis of terrestrial arthropod community and biomass in differently managed rice fields in Korea

The present study was conducted to investigate the differences in managed farming practices, including low-intensive farming, duck farming, and golden apple snail farming, in a rice ecosystem by comparing terrestrial arthropod communities. A total of 75 species from 70 genera belonging to 43 families in 11 orders were identified from 9,622 collected arthropods. Araneae, Hemiptera, and Coleoptera were the richest taxa. Collembola was the most abundant, followed by Diptera, Hemiptera, and Araneae. Bray- Curtis similarity among the farming practices was very high (76.7%). The biodiversity of each farming practice showed a similar seasonality pattern. The richest species group was the predators, followed by the herbivores. The species richness and diversity of ecologically functional groups among the farming practices were not statistically significant, except for the abundance of predators in golden apple snail farming. The biodiversity seasonality of ecological functional groups in each farming practice showed similar patterns. The biomass of Araneae, Hemiptera, Coleoptera, and Diptera was greater than the other taxa, in general. The biomass of each ecological functional group showed little difference and the biomass fluctuation patterns in each farming practice were almost the same. Collectively, the community structures and biodiversity of terrestrial arthropods among the farming practices in the present study were not different. The present study may contribute to sustain rich biodiversity in irrigated rice fields and to advanced studies of food webs or energy flow structures in rice fields for ecological and sustainable agriculture.

An introduced plant is associated with declines in terrestrial arthropods, but no change in stream invertebrates

Riverine systems often spread non-native species, yet the co-occurring impacts of introduced riparian vegetation on aquatic- and terrestrial-derived resources are unknown. We compared aquatic and terrestrial arthropod communities and their flux into and out of streams in riparian reaches invaded and uninvaded by Robinia neomexicana, a woody plant introduced to a western Colorado watershed. We found that invaded reaches had fewer terrestrial arthropods collected off foliage, conceivably because of the plant’s later leaf-out phenology. Overall, seasonal and annual factors best described terrestrial and aquatic arthropod communities. However, when we evaluated vegetation and stream characteristics in lieu of season and year, we found terrestrial arthropod biomass and richness were negatively related to cover of R. neomexicana and positively related to vegetative cover, forb cover, and vertical vegetation structure. Our results suggest ecosystems respond to landscape variation differently, where directly related food web components (i.e., terrestrial arthropods on introduced vegetation) respond stronger than more distally related constituents (i.e., aquatic insects).

Reducing allochthonous resources in a subarctic grassland alters arthropod food webs via predator diet and density

AbstractEmergent aquatic insects can be major conduits of resources moving from freshwater to adjacent terrestrial ecosystems. These allochthonous resources can influence the structure and function of adjacent ecosystems, yet their effect on arthropod consumer populations remains largely unknown. In this study, we investigated how flying adult midges influence terrestrial arthropod food webs in subarctic grasslands by blocking midge inputs over four years in 2 × 2‐m plots near the shore of Lake Mývatn, Iceland, where midge abundances are naturally high. We examined responses of terrestrial arthropods by measuring their densities, community composition, and stable isotopes (δ13C) in midge‐exclusion and open (control) plots. Cage treatments significantly reduced midge deposition into exclusion plots (99% reduction) relative to control plots but were designed to allow ground‐active arthropods to move freely among plots. Predator densities (e.g., spiders and harvestmen) were on average 30% lower in exclusion plots relative to control plots, while no other trophic guild (detritivores, omnivores, or herbivores) showed a response to midge exclusion. As a result, blocking midges shifted arthropod communities toward a composition dominated by springtails, mites, and aphids relative to large predators such as wolf spiders and harvestmen. All trophic guilds (detritivores, omnivores, and predators), except for herbivores, were more depleted in δ13C in midge‐exclusion plots, indicating an increased reliance on terrestrial (i.e., plant‐based) resources when midge inputs were blocked. Arthropod predators were the only guild that had both a depleted δ13C and a negative density response to midge exclusion. Apart from predators, these results indicate a weak association between resource type (aquatic vs. terrestrial) and density responses across most arthropod guilds in this grassland system. Overall, our findings suggest that aquatic insect subsidies have significant effects on terrestrial arthropod communities, but predators appear most responsive to insect allochthony in subarctic grasslands.

Trait-based ecology of terrestrial arthropods.

ABSTRACTIn focusing on how organisms' generalizable functional properties (traits) interact mechanistically with environments across spatial scales and levels of biological organization, trait‐based approaches provide a powerful framework for attaining synthesis, generality and prediction. Trait‐based research has considerably improved understanding of the assembly, structure and functioning of plant communities. Further advances in ecology may be achieved by exploring the trait–environment relationships of non‐sessile, heterotrophic organisms such as terrestrial arthropods, which are geographically ubiquitous, ecologically diverse, and often important functional components of ecosystems. Trait‐based studies and trait databases have recently been compiled for groups such as ants, bees, beetles, butterflies, spiders and many others; however, the explicit justification, conceptual framework, and primary‐evidence base for the burgeoning field of ‘terrestrial arthropod trait‐based ecology’ have not been well established. Consequently, there is some confusion over the scope and relevance of this field, as well as a tendency for studies to overlook important assumptions of the trait‐based approach. Here we aim to provide a broad and accessible overview of the trait‐based ecology of terrestrial arthropods. We first define and illustrate foundational concepts in trait‐based ecology with respect to terrestrial arthropods, and justify the application of trait‐based approaches to the study of their ecology. Next, we review studies in community ecology where trait‐based approaches have been used to elucidate how assembly processes for terrestrial arthropod communities are influenced by niche filtering along environmental gradients (e.g. climatic, structural, and land‐use gradients) and by abiotic and biotic disturbances (e.g. fire, floods, and biological invasions). We also review studies in ecosystem ecology where trait‐based approaches have been used to investigate biodiversity–ecosystem function relationships: how the functional diversity of arthropod communities relates to a host of ecosystem functions and services that they mediate, such as decomposition, pollination and predation. We then suggest how future work can address fundamental assumptions and limitations by investigating trait functionality and the effects of intraspecific variation, assessing the potential for sampling methods to bias the traits and trait values observed, and enhancing the quality and consolidation of trait information in databases. A roadmap to guide observational trait‐based studies is also presented. Lastly, we highlight new areas where trait‐based studies on terrestrial arthropods are well positioned to advance ecological understanding and application. These include examining the roles of competitive, non‐competitive and (multi‐)trophic interactions in shaping coexistence, and macro‐scaling trait–environment relationships to explain and predict patterns in biodiversity and ecosystem functions across space and time. We hope this review will spur and guide future applications of the trait‐based framework to advance ecological insights from the most diverse eukaryotic organisms on Earth.

An introduced plant affects aquatic-derived carbon in the diets of riparian birds.

Non-native plants can impact riparian ecosystem function through diverse terrestrial and aquatic pathways, with cascading effects on food webs. Invasion-mediated vegetation changes can depress terrestrial arthropod communities and alter arthropod flux across the aquatic-terrestrial interface. We investigated the effects of a non-native woody plant, Robinia neomexicana, on insect contributions to riparian songbird diets. This plant was introduced over 100 years ago to the Clear Creek drainage in northwestern Colorado (USA) from its native range, which extends into southern Colorado. We used stable isotope analysis of insects and avian feces to 1) assess whether the relative contributions of aquatic- and terrestrial-derived arthropod prey differed between reference sites and sites invaded by R. neomexicana, and 2) quantify the amount of aquatic- and terrestrial-derived resources consumed by an insectivorous songbird assemblage. Two species of insectivorous songbirds consumed more aquatic insects in invaded sites compared to reference sites. This change in terrestrial- and aquatic-derived prey in bird diets in response to a near-range plant invasion suggests that the introduction of novel species from more distant native ranges could produce similar or stronger effects. Overall, the songbird community consumed approximately 34% aquatic resources, which highlights the importance of these subsidies to riparian consumers. Our investigation of insect subsidies demonstrates how introduced species can indirectly affect food webs and provides insight into the plasticity of riparian consumer responses.

Response of ground and rove beetles (Coleoptera: Carabidae, Staphylinidae) to operational oil sands mine reclamation in northeastern Alberta, a case study

Species loss caused by anthropogenic disturbance threatens forest ecosystems globally. Until 50 years ago, the major sources of boreal forest disturbance in western Canada were a combination of forest wild fire events, pest insect outbreaks, and forest timber harvesting. However, in the 1960s, when the oil boom started in Alberta, oil and gas development along with oil sands mining quickly became another major forest disturbance agent. In this case study we report the effects of operational oil sands mine reclamation on terrestrial arthropod communities and compare them with nearby burned and mature forest sites as a way to provide a benchmark from which to understand the long-term trajectory of recovery for these groups. During the summer of 2016 over 6700 epigaeic beetles were collected using pitfall traps. A total of 43 species of ground beetles and 118 species of rove beetles were collected. Epigaeic beetle assemblages differed between the reclaimed, burned, and mature forest sites. Partitioning of beta diversity in the reclaimed, burned areas and mature forests indicated that species turnover formed the largest component of diversity. Species richness patterns were similar among sites; however, cluster analysis indicated that epigaeic beetle assemblages were only 20% similar between the reclaimed and natural sites. Although ground beetles of the reclaimed area showed positive spatial autocorrelation among treatments, both ground and rove beetles showed responses to the reclamation treatments. The reclaimed areas were dominated by small- to medium-sized open-habitat eurytopic species, whereas the fire and mature forest sites were dominated by larger forest species. The reclaimed area of this case study constitutes a novel, reconstructed ecosystem that is clearly not equivalent in species assemblage to burnt stands of similar age or to mature forest stands.

Expedited assessment of terrestrial arthropod diversity by coupling Malaise traps with DNA barcoding

Monitoring changes in terrestrial arthropod communities over space and time requires a dramatic increase in the speed and accuracy of processing samples that cannot be achieved with morphological approaches. The combination of DNA barcoding and Malaise traps allows expedited, comprehensive inventories of species abundance whose cost will rapidly decline as high-throughput sequencing technologies advance. Aside from detailing protocols from specimen sorting to data release, this paper describes their use in a survey of arthropod diversity in a national park that examined 21 194 specimens representing 2255 species. These protocols can support arthropod monitoring programs at regional, national, and continental scales.

Diel periodicity of a terrestrial arthropod community: diversity, composition, and body size

1. Activity patterns of arthropods lead to consistent changes in community composition in many ecosystems, but this daily turnover in community membership is poorly characterised. This study used passive collection methods of ground and air active arthropods, feeding guild assignment, and body size measurements to characterise changes in a terrestrial arthropod community between consecutive 4‐h time intervals.2. We found that arthropod communities are highly structured in time, with the time of sample collection significantly affecting family richness, relative abundance, abundance of feeding guilds, community dissimilarity, community turnover rates, and average body sizes within taxonomic orders.3. Community dissimilarity is periodic on two timescales, 12 and 24 h. Morning and evening communities were similar to each other and supported a unique assemblage that occurred during the transition from highly dissimilar night and day arthropod communities.4. The results offered support for previous findings that night‐active arthropods are generally larger than day‐active ones, with the pattern holding for some but not all orders.5. These findings demonstrate that species‐specific daily activity patterns influence community composition in a predictable manner, with characteristic repeating time communities within a single habitat.