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This study analyzes arthropod biomass and abundance to track the changes in arthropod occurrence in relation to pesticide use in three winter wheat cropping systems managed at different intensities (organic, conventional, and hybrid). Arthropod occurrence was surveyed using three collection tools: sweeping nets, eclector traps, and yellow traps. Sampling was conducted over three years from 2020 to 2022 with 588 samples collected. The wet weight of the captured organisms was determined and arthropod abundance calculated. The application of a NOcsPS (no chemical-synthetic pesticides) strategy, a new hybrid cultivation method realized with optimized use of nitrogen fertilizers but without chemical-synthetic pesticides, showed a higher arthropod occurrence and performed more convincingly regarding produced arthropod biomass and abundance than the other cropping variants. The results also demonstrate a dependence of the obtained insect indices on the collection method. Although arthropod biomass and abundance correlated for all collection methods, the combination of various methods as well as multiple procedures of sample analysis gives a more realistic and comprehensive view of the impact of the wheat cultivation systems on the arthropod fauna than one-factor analyses. [ABSTRACT FROM AUTHOR]

Plant invasions threaten native biodiversity, but detailed information on patterns and mechanisms of diversity changes across multitrophic levels remains unknown. Alien plants can reduce richness of native plants, thereby negatively affecting arthropods and their multitrophic interactions. In particular, tall invasive trees may limit native understory plants and associated arthropods more than small invasive shrubs, which may support light-demanding taxa under their more open canopies. In this study, we investigated how two non-native highly invasive species (shrub Sorbaria sorbifolia and tree Amelanchier spicata) and two native species (shrub Rubus idaeus and tree Prunus padus) distributed in monodominant patches along roadsides in SW Finland affect arthropod-feeding guild biomass and food webs. Under trees, regardless of their origin, the diversity and biomass of understory plants and arthropods living in the canopy and on the ground was significantly reduced compared to shrubs, which had higher biodiversity and more significant interactions between feeding guilds and understory plants. The higher biomass of native understory plants increased the abundance of herbivores under the shrubs, and thus indirectly predators. The species richness of understory plants determined the richness of saprophagous organisms in native stands. We conclude that more open roadside shrub canopies support greater plant and arthropod biodiversity and more complex food web structures compared to shady tree stands, and that alien shrubs do not necessarily reduce arthropod biodiversity. The study opens up the possibility of predicting arthropod composition and biomass using functional attributes of understory vegetation and the origin, physiognomy and species identity of overstory dominants. [ABSTRACT FROM AUTHOR]

Food availability plays a key role affecting almost every aspect of bird ecology, including bird population, distribution, reproduction, and behavior. Understanding the functional relationship between prey availability and insectivorous birds’ diet is important in the current scenario of habitat loss and declining of insect and bird populations. We used a fecal metabarcoding approach coupled with prey availability sampling (arthropod abundance and biomass) to test for evidence of selective foraging in a shrub-steppe passerine assemblage over the 2017–2019 breeding seasons in semi-natural steppes of central Spain. The results showed that the six bird species selected specific arthropod taxa. Heteroptera, Orthoptera, Araneae, Lepidoptera and some Coleoptera families were the main selected prey taxa, while Formicidae appeared to be avoided, suggesting that shrub-steppe passerines tend to select prey items providing essential nutrients and energy during the breeding season, while poor quality ones are neglected. Our findings highlight the utility of metabarcoding dietary data to assess prey selection patterns in insectivorous passerines and provide valuable information for the development of conservation and management programs to ensure the long-term availability of crucial food resources for shrub-steppe birds and other insectivores.

Tropical rainforests around the world are rapidly being converted into cash crop agricultural systems. The associated massive losses of plant and animal species lead to changes in arthropod food webs and the energy fluxes therein. These changes are poorly understood, in particular in the extremely biodiverse canopies of tropical ecosystems. Using canopy fogging followed by stable isotope and energy flux analyses, we show that land‐use conversion from rainforest to rubber and oil palm plantations not only causes a drastic reduction in energy fluxes of up to 75%, but also shifts fluxes among trophic groups. While rainforest featured high levels of both herbivory and algae‐microbivory, and a balanced ratio of herbivory to predation, relative fluxes were shifted towards predation in rubber and towards herbivory in oil palm plantations, indicating profound shifts in ecosystem functioning. Our results highlight that the ongoing loss of animal biodiversity and biomass in tropical canopies degrades animal‐driven functions and restructures canopy food webs. [ABSTRACT FROM AUTHOR]

Arthropod biomass is a key element in ecosystem functionality and a basic food item for many species. It must be estimated through traditional costly field sampling, normally at just a few sampling points. Arthropod biomass and plant productivity should be narrowly related because a large majority of arthropods are herbivorous, and others depend on these. Quantifying plant productivity with satellite or aerial vehicle imagery is an easy and fast procedure already tested and implemented in agriculture and field ecology. However, the capability of satellite or aerial vehicle imagery for quantifying arthropod biomass and its relationship with plant productivity has been scarcely addressed. Here, we used unmanned aerial vehicle (UAV) and satellite Sentinel‐2 (S2) imagery to establish a relationship between plant productivity and arthropod biomass estimated through ground‐truth field sampling in shrub steppes. We UAV‐sampled seven plots of 47.6–72.3 ha at a 4‐cm pixel resolution, subsequently downscaling spatial resolution to 50 cm resolution. In parallel, we used S2 imagery from the same and other dates and locations at 10‐m spatial resolution. We related several vegetation indices (VIs) with arthropod biomass (epigeous, coprophagous, and four functional consumer groups: predatory, detritivore, phytophagous, and diverse) estimated at 41–48 sampling stations for UAV flying plots and in 67–79 sampling stations for S2. VIs derived from UAV were consistently and positively related to all arthropod biomass groups. Three out of seven and six out of seven S2‐derived VIs were positively related to epigeous and coprophagous arthropod biomass, respectively. The blue normalized difference VI (BNDVI) and enhanced normalized difference VI (ENDVI) showed consistent and positive relationships with arthropod biomass, regardless of the arthropod group or spatial resolution. Our results showed that UAV and S2‐VI imagery data may be viable and cost‐efficient alternatives for quantifying arthropod biomass at large scales in shrub steppes. The relationship between VI and arthropod biomass is probably habitat‐dependent, so future research should address this relationship and include several habitats to validate VIs as proxies of arthropod biomass. [ABSTRACT FROM AUTHOR]

Plant quantity and quality can independently affect the diversity of the entire arthropod communities and multiple arthropod taxa in grassland ecosystems. However, it remains unclear how these effects on arthropod taxa at one trophic level propagate through food web to influence the diversity of higher trophic levels.We performed a monoculture experiment with 15 herbaceous species in the Inner Mongolian grassland to investigate how natural variations in plant productivity and host leaf traits affect herbivore taxon richness, which, in turn, affects predator taxon richness.For herbivores, plant productivity indirectly promoted herbivore taxon richness by increasing herbivore biomass, which was attributed to the increases in the richness of dominant sucking herbivores and endophytes with high food requirements. However, the high plant quality indicator (e.g. high leaf protein, phosphorus and water contents, and high leaf protein to carbohydrate ratio) directly increased, whereas the low plant quality indicator (e.g. high leaf lignin content) directly decreased herbivore taxon richness. Taxon richness of chewing and sucking herbivores with specific feeding modes (tearing or sucking mouthparts) showed strong positive responses to increasing plant quality.For predators, herbivore taxon richness, rather than herbivore biomass, mainly mediated the positive effects of plant productivity and the high plant quality indicator, but the negative effect of the low plant quality indicator, on predator taxon richness. At the feeding guild level, the taxon richness of parasitoids, other predators and spiders exhibited positive responses to different herbivores, which was attributed to their different diet preferences. Predator diversity could be promoted by prey partitioning among predator guilds facilitating species coexistence. At the family level, the taxon richness of most predator families was positively correlated with that of more than one herbivore family, suggesting that high predator diversity may be caused by balanced diets owing to high prey diversity.Synthesis. Natural variations in plant quantity and quality can substantially affect the diversity of herbivores and cascade up the food web to affect predators. Specificity and mechanisms of feeding have a large impact on the responses of arthropod guilds at each trophic level. [ABSTRACT FROM AUTHOR]

Background Throughout the world, intensive dairy farming has resulted in grasslands almost devoid of arthropods and birds. Meadow birds appear to be especially vulnerable during the chick-rearing period. So far, studies have focused mainly on describing population declines, but solutions to effectively stop these trends on the short-term are lacking. In this study at a single farm, we experimentally manipulated soil moisture through occasional irrigation, to mitigate against early season drainage and create favorable conditions for the emergence of above-ground arthropods during the meadow bird chick rearing phase. Methods To guarantee the presence of at least a sizeable arthropod community for the measurement of effects of wetting, we selected a farm with low intensity management. The land use and intensity of the study site and surroundings were categorized according to the national land use database and quantified using remote sensing imagery. From May 1 to June 18, 2017, we compared a control situation, with no water added, to two wetting treatments, a “short-term” (3 weeks) treatment based on wetting on warm days with a sprinkler system and a “long-term” treatment next to a water pond with a consistently raised water table from 2010. We measured soil temperature, soil moisture and resistance as well as the biomass of arthropods at 3-day intervals. Flying arthropods were sampled by sticky traps and crawling arthropods by pitfall traps. Individual arthropods were identified to Order and their length recorded, to assess their relevance to meadow bird chicks. Results The land use analysis confirmed that the selected dairy farm had very low intensity management. This was different from most of the surrounding area (20 km radius), characterized by (very) high intensity land use. The experiments showed that irrigation contributed to cooler soils during midday, and that his happened already in the early part of the season; the differences with the control increased with time. In the short- and long-term treatments, soil moisture increased and soil resistance decreased from the mid-measurement period onward. Compared with the control, cumulative arthropod biomass was higher in the long-term treatment, but showed no change in the irrigation treatment. We conclude that small-scale interventions, such as occasional irrigation, favorably affected local soil properties. However, the effects on above-ground arthropod abundance currently appear limited or overridden by negative landscape-scale processes on arthropods.

Background: Throughout the world, intensive dairy farming has resulted in grasslands almost devoid of arthropods and birds. Meadow birds appear to be especially vulnerable during the chick-rearing period. So far, studies have focused mainly on describing population declines, but solutions to effectively stop these trends on the short-term are lacking. In this study at a single farm, we experimentally manipulated soil moisture through occasional irrigation, to mitigate against early season drainage and create favorable conditions for the emergence of above-ground arthropods during the meadow bird chick rearing phase. Methods: To guarantee the presence of at least a sizeable arthropod community for the measurement of effects of wetting, we selected a farm with low intensity management. The land use and intensity of the study site and surroundings were categorized according to the national land use database and quantified using remote sensing imagery. From May 1 to June 18, 2017, we compared a control situation, with no water added, to two wetting treatments, a "short-term" (3 weeks) treatment based on wetting on warm days with a sprinkler system and a "long-term" treatment next to a water pond with a consistently raised water table from 2010. We measured soil temperature, soil moisture and resistance as well as the biomass of arthropods at 3-day intervals. Flying arthropods were sampled by sticky traps and crawling arthropods by pitfall traps. Individual arthropods were identified to Order and their length recorded, to assess their relevance to meadow bird chicks. Results: The land use analysis confirmed that the selected dairy farm had very low intensity management. This was different from most of the surrounding area (20 km radius), characterized by (very) high intensity land use. The experiments showed that irrigation contributed to cooler soils during midday, and that his happened already in the early part of the season; the differences with the control increased with time. In the short- and long-term treatments, soil moisture increased and soil resistance decreased from the mid-measurement period onward. Compared with the control, cumulative arthropod biomass was higher in the long-term treatment, but showed no change in the irrigation treatment. We conclude that small-scale interventions, such as occasional irrigation, favorably affected local soil properties. However, the effects on above-ground arthropod abundance currently appear limited or overridden by negative landscape-scale processes on arthropods. [ABSTRACT FROM AUTHOR]

The detrimental effects of invasive parasites on hosts often increase under poor environmental conditions. Both natural fluctuations in environmental conditions and habitat management measures can temporarily cause adverse environmental effects. In this study, we investigated the interaction between the invasive parasitic fly Philornis downsi , control of invasive plants and precipitation on the breeding success of Darwin's finches. Introduced plant species have invaded a unique forest on the Galapagos island of Santa Cruz, which is a key habitat for Darwin's finches. The Galapagos National Park Directorate applies manual control and herbicides to combat this invasion. We hypothesized that these measures led to a reduction in the arthropod food supply during chick rearing, which in turn caused mortality in chicks that were already weakened by parasitism. We compared food availability in three study sites of varying degrees of weed management. To assess the interaction of parasitism and weed management, we experimentally reduced P. downsi abundance in nests in all three study sites. The key result suggests that there is an increase in the adverse effect of parasitism under unfavourable habitat conditions. As predicted, we found a negative additive effect of parasitism and weed management on the breeding success of the insectivorous warbler finch (Certhidea olivacea), but not on the omnivorous small tree finch (Camarhynchus parvulus), which was strongly affected by parasitism independently of weed management. Management measures can temporarily decrease environmental quality and reduce resistance/tolerance to invasive species. This should be considered when applying management measures to habitats of vulnerable species. • An invasive parasite reduces breeding success of Darwin's finches. • Weed management has a negative impact on breeding success and arthropod biomass. • We found an interaction between parasitism and weed management for the insectivorous warbler finch. • Warbler finches cannot compensate for parasitism in the recently managed area. • Indirect effects of weed management should be considered in management decisions. [ABSTRACT FROM AUTHOR]

Animals make directional movements toward resources to satisfy nutritional, reproductive, and protection needs. We evaluated resource selection by the spiny rat (Thrichomys fosteri) in a heterogeneous habitat, disentangling the relative importance of habitat structure, escape cover, food availability, and intraspecific competition. The last 2 variables were estimated directly by explicitly incorporating their spatiotemporal variation in the model. We radiotracked 15 males and 5 females for a median of 10 days per month for 17 months. Used and available resources were estimated at the home-range scale by intersecting the radiotracking locations (used) and random points (available) with resource maps that were either temporally static (measured only once; palm density and bromeliad cover) or dynamic (with temporal variation; arthropod biomass and conspecific abundance). We performed a resource selection function analysis using conditional logistic regression stratified by each individual location. Within their home ranges, spiny rats selected areas with high bromeliad cover and arthropod biomass. There was a negative interaction between conspecific abundance and arthropod biomass. We showed that resource selection by individuals takes into account multiple resources that vary in space and time. Individuals tended to select areas with high escape cover and high food availability balanced by low intraspecific competition. [ABSTRACT FROM AUTHOR]

We investigated the influence of Old World bluestem (Bothriochloa ischaemum; OWB) monocultures on grassland bird abundance through analysis of vegetation structure and food availability. We compared breeding bird density, vegetation structure and composition, and arthropod biomass between six native grass and six OWB fields in the southern Great Plains. The OWB fields supported 1.70 ± 0.27 (mean ± SE) Grasshopper Sparrows (Ammodramus savannarum) per ha compared to 0.95 ± 0.25 in native grass fields, but total species richness was greater in native grass fields (40 versus 28 species). Density of some bird species was correlated with vegetation structure regardless of field type, suggesting that management practices may be more influential than plant species composition. Mean arthropod biomass was 3.39X greater in native grass fields than in OWB monocultures. Native grass fields provided habitat for a larger complement of birds than did OWB monocultures, and reduced food availability in OWB fields suggests a mechanism for that difference. [ABSTRACT FROM AUTHOR]

In Morocco we tested the consistency between an a priori habitat classification based on topography, hydrology, vegetation structure and composition, and an a posteriori classification based on arthropod assemblages, in a plain supporting wild endangered Houbara Bustards. According to vegetation structure, we defined seven a priori habitats that differed significantly in perennial cover and height. A multivariate multiple regression analysis showed a significant relationship between arthropod assemblages and vegetation structure. Canonical Analyses of Principal Coordinates, conducted simultaneously on direct searches of arthropods and trapping data, showed significant differences between assemblages in both cases, and produced two similar constrained ordinations of six a posteriori habitats: esparto grass (Stipa tenacissima), temporarily flooded areas, fields, "reg" with short perennials, "reg" with tall perennials and wadis. The two sampling methods reflected a dominance of ants and beetles. Arthropod biomasses increased significantly in spring and then decreased significantly in summer for beetles, and in autumn for ants. No strong differences appeared between habitats within seasons, especially in spring, indicating a uniform distribution of food resources during the Houbara breeding season. The "reg" with short perennials had the highest ant biomass in summer. This "reg" and fields also supported the highest arthropod biomass in autumn. Variation in arthropod biomass was a pertinent factor that should be integrated into Houbara habitat selection studies. The definition of habitat availability based on easily identifiable landscape units, combined with empirical tests on arthropod communities provided an accurate classification for habitat selection studies and conservation planning. In Morocco we tested the consistency between an a priori habitat classification based on topography, hydrology, vegetation structure and composition, and an a posteriori classification based on arthropod assemblages, in a plain supporting wild endangered Houbara Bustards. According to vegetation structure, we defined seven a priori habitats that differed significantly in perennial cover and height. A multivariate multiple regression analysis showed a significant relationship between arthropod assemblages and vegetation structure. Canonical Analyses of Principal Coordinates, conducted simultaneously on direct searches of arthropods and trapping data, showed significant differences between assemblages in both cases, and produced two similar constrained ordinations of six a posteriori habitats: esparto grass (Stipa tenacissima), temporarily flooded areas, fields, "reg" with short perennials, "reg" with tall perennials and wadis. The two sampling methods reflected a dominance of ants and beetles. Arthropod biomasses increased significantly in spring and then decreased significantly in summer for beetles, and in autumn for ants. No strong differences appeared between habitats within seasons, especially in spring, indicating a uniform distribution of food resources during the Houbara breeding season. The "reg" with short perennials had the highest ant biomass in summer. This "reg" and fields also supported the highest arthropod biomass in autumn. Variation in arthropod biomass was a pertinent factor that should be integrated into Houbara habitat selection studies. The definition of habitat availability based on easily identifiable landscape units, combined with empirical tests on arthropod communities provided an accurate classification for habitat selection studies and conservation planning.… [ABSTRACT FROM AUTHOR]

Summary 1.Theoretical arguments suggest that distributions of migratory birds in winter should match patterns of food availability, but in reality the match between migrants and their food may be imperfect because, for various reasons, birds may be unable to ‘track’ food resources. We tested the hypothesis that food availability influences the distribution of migratory canopy-foraging insectivorous warblers wintering in Jamaica. 2.Over a wide spatial scale (24 sites on the island), warbler abundance varied significantly among sites and habitats and was significantly dependent on measures of arthropod biomass. Alternative factors (vegetation characteristics, resident bird competitor abundance, predator abundance) were not correlated with warbler abundance. 3.Over a short temporal scale (about 2 weeks) at a single site, warbler abundance increased as predicted quantitatively after a natural, rapid increase in arthropod biomass. 4.Over a longer temporal scale (the duration of a winter), changes in density and persistence of individually marked American redstarts (Setophaga ruticilla, L.) on six sites corresponded with concurrent fluctuations in arthropod biomass. 5.These results document a strong association between arthropod biomass and warbler abundance in time and space, suggesting that warblers wintering in Jamaica distribute themselves in response to food resources. 6.We hypothesize that dominance hierarchies and variable movement strategies operate in concert with birds’ responses to food to influence the distribution of wintering warblers at different spatial scales. Whether food availability determines habitat quality remains to be investigated. [ABSTRACT FROM AUTHOR]

The woolly monkey's (Lagothrix lagotricha) diet consists primarily of fruits, and for some populations fruit availability predicts its frequency in the diet. Woolly monkeys also eat new leaves, flowers, seeds and arthropods, but it is unclear whether arthropods are consumed in proportion to their environmental availability. We tested the hypothesis that arthropod consumption by woolly monkeys depends on availability. We studied a group of woolly monkeys for 10 months in 2013-2014, in Cueva de los Guácharos National Park, Colombia, in order to test the hypothesis that arthropod consumption by woolly monkeys depends on availability. We carried out surveys of plant phenology each month for 10 months to estimate fruit productivity, and every 2 months we also surveyed 3 canopy substrates (leaves, mosses and bromeliads) to quantify variation in arthropod biomass. During this time, we also quantified the diet of a woolly monkey group. The items most consumed were fruits (60%), followed by arthropods (24%), leaves (13%) and miscellaneous other items (3%). Arthropod biomass in the canopy did not vary considerably over the 10 months (0.014-0.037 g/g substrate) but was lower at the end of the second rainy season. A positive correlation was found between availability and entomophagy, but only when arthropods were relatively abundant. We did not find a relationship between arthropod and fruit feeding frequencies. Our results indicate that arthropods are prevalent in the diet of the woolly monkeys due to their abundance in Andean forest canopies., (© 2019 S. Karger AG, Basel.)

Effects of tillage practice and nitrogen source on arthropod biomasswere measured in experimental sorghum agroecosystems. Crops receivedeither inorganic N, or N supplied from a winter crop of crimson clover, in a split-plot design using eight 0.1-ha plots. Four of the 8 plots received conventional tillage and 4 were maintained under a no-tillage regime; each plot was split into winter clover (organic N) and winter rye (inorganic N). Arthropods were enumerated and biomasses were determined in functional groups. Sucking herbivorous insects, parasitic insects, and dipterans were the most abundant groups numerically. Insect biomass was dominated by sucking herbivores, chewing herbivores, and dipterans. Sorghum supported a much larger biomass of arthropods than did weeds in the plots. The source of N was more importantthan tillage type in affecting arthropod biomass. Plots receiving inorganic N had significant increases in arthropod biomass during the summer; plots with organic sources of N had little or no increase in biomass of arthropods. Crop production was comparable for the 8 plots.Differences in N concentration in crops and weeds may account for differences in arthropod biomass. [ABSTRACT FROM AUTHOR]