Dispersal is a key influence on species' persistence, particularly in the context of habitat fragmentation and environmental change. Previously, residual population synchrony has been demonstrated to be an effective proxy for dispersal in mobile butterflies (Powney et al. 2012).
View Article and Find Full Text PDFSeventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions.
View Article and Find Full Text PDFThe study of insect responses to colour has mainly focused on flying species and morphs, however colour cues are likely to be important for insect positioning within the canopy. We examine the role of illumination colour in canopy positioning of apterous Myzus persicae (Sulzer) using both a field experiment, utilising various UV-manipulating optical filters, and a laboratory experiment using video tracking of individuals illuminated by a variable intensity UVA-Blue-Green LED-array. In the field experiment, approximately twice as many aphids were located on exposed leaf surfaces under UV-deficient environments compared to UV-rich environments.
View Article and Find Full Text PDFClimate change poses a threat to global food security with extreme heat events causing drought and direct damage to crop plants. However, by altering behavioural or physiological responses of insects, extreme heat events may also affect pollination services on which many crops are dependent. Such effects may potentially be exacerbated by other environmental stresses, such as exposure to widely used agro-chemicals.
View Article and Find Full Text PDFHigh resource availability can reduce anti-herbivore resistance (a plant's ability to defend against herbivores and reduce damage) in rice, L, but may also increase tolerance (a plant's ability to withstand damage by, for example, compensatory growth). Through a series of greenhouse, screenhouse and field experiments, this study examines fitness (survival and development × reproduction) of the brown planthopper, (Stål), on resistant (IR62) and susceptible (IR22) rice varieties and age-related rice tolerance to planthopper damage under varying resource (nitrogenous fertilizer) availability. Planthoppers reared on IR62 in the greenhouse had lower fitness than planthoppers on IR22.
View Article and Find Full Text PDFArthropod community composition in agricultural landscapes is dependent on habitat characteristics, such as plant composition, landscape homogeneity and the presence of key resources, which are usually absent in monocultures. Manipulating agroecosystems through the insertion of in-field floral resources is a useful technique to reduce the deleterious effects of habitat simplification. Food web analysis can clarify how the community reacts to the presence of floral resources which favour ecosystem services such as biological control of pest species.
View Article and Find Full Text PDFFlower strips are commonly recommended to boost biodiversity and multiple ecosystem services (e.g., pollination and pest control) on farmland.
View Article and Find Full Text PDFThe importance of managing land to optimize carbon sequestration for climate change mitigation is widely recognized, with grasslands being identified as having the potential to sequester additional carbon. However, most soil carbon inventories only consider surface soils, and most large-scale surveys group ecosystems into broad habitats without considering management intensity. Consequently, little is known about the quantity of deep soil carbon and its sensitivity to management.
View Article and Find Full Text PDFEcosystems provide multiple services upon which humans depend. Understanding the drivers of the ecosystem functions that support these services is therefore important. Much research has investigated how species richness influences functioning, but we lack knowledge of how other community attributes affect ecosystem functioning.
View Article and Find Full Text PDFThe prediction of pest-control functioning by multi-predator communities is hindered by the non-additive nature of species functioning. Such non-additivity, commonly termed an emergent multi-predator effect, is known to be affected by elements of the ecological context, such as the structure and composition of vegetation, in addition to the traits of the predators themselves. Here we report mesocosm experiments designed to test the influence of plant density and species composition (wheat monoculture or wheat and faba bean polyculture) on the emergence of multi-predator effects between Adalia bipunctata and Chrysoperla carnea, in their suppression of populations of the aphid Metopolophium dirhodum.
View Article and Find Full Text PDFChanges in predator species richness can have important consequences for ecosystem functioning at multiple trophic levels, but these effects are variable and depend on the ecological context in addition to the properties of predators themselves. Here, we report an experimental study to test how species identity, community attributes, and community structure at the herbivore level moderate the effects of predator richness on ecosystem functioning. Using mesocosms containing predatory insects and aphid prey, we independently manipulated species richness at both predator and herbivore trophic levels.
View Article and Find Full Text PDFEcological systems often exhibit a positive but saturating diversity-function curve. Variation in the mechanisms generating this relationship can alter the slope and variance of the curve, with implications for the optimal management of biodiversity for ecosystem services. In biological control, prevalence of selection effects supports augmentation of the most effective natural enemy, but complementarity effects support augmentation of natural enemy diversity.
View Article and Find Full Text PDFBiodiversity-ecosystem functioning theory would predict that increasing natural enemy richness should enhance prey consumption rate due to functional complementarity of enemy species. However, several studies show that ecological interactions among natural enemies may result in complex effects of enemy diversity on prey consumption. Therefore, the challenge in understanding natural enemy diversity effects is to predict consumption rates of multiple enemies taking into account effects arising from patterns of prey use together with species interactions.
View Article and Find Full Text PDFThe influence of temporal and spatial heterogeneity in seed availability on the foraging behaviour of the harvester ant Messor arenarius was studied in an arid shrubland in the Negev Desert, Israel. The study investigated the implications of behavioural responses to heterogeneity in seed availability for the seed predation process and the potential for feedback effects on vegetation. Vegetation and seed rain were monitored across two landscape patch types (shrub patches and inter-shrub patches) in 1997.
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