ORCID Profile
0000-0002-0563-485X
Current Organisation
Washington State University
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Publisher: Public Library of Science (PLoS)
Date: 22-10-2013
Publisher: Wiley
Date: 19-02-2010
DOI: 10.1111/J.1461-0248.2009.01428.X
Abstract: More erse communities of consumers typically use more resources, which often is attributed to resource partitioning. However, experimentally demonstrating this role of resource partitioning in erse communities has been difficult. We used an experimental response-surface design, varying intra- and interspecific consumer densities, to compare patterns of resource exploitation between simple and erse communities of aphid predators. With increasing density, each single consumer species rapidly plateaued in its ability to extract more resources. This suggests intraspecific competition for a subset of the resource pool, a hallmark of resource partitioning. In contrast, more erse-predator communities achieved greater overall resource depletion. By statistically fitting mechanistic models to the data, we demonstrated that resource partitioning rather than facilitation provides the better explanation for the observed differences in resource use between simple and erse communities. This model-fitting approach also allowed us to quantify overlap in resource use by different consumer species.
Publisher: Frontiers Media SA
Date: 06-06-2019
Publisher: Elsevier BV
Date: 09-2017
Publisher: American Society for Horticultural Science
Date: 10-2019
Abstract: Artificial pollination management strategies are a potential solution to improving the livelihoods of smallholder cacao farmers by increasing crop productivity in situations when pollination services are limiting. However, field-based research trials evaluating the yield benefits of artificial pollination management strategies within intensified cacao systems are lacking. Thus, in an intensively managed cacao system, we evaluated the effects of artificial pollination condition (i.e., pollen genotype, pollination intensity, and pollination synchrony) on fruit development and yield in three high-yielding cacao clones. Artificial pollination, regardless of intensity, significantly increased fruit set and yield. Pollination synchrony had a significant effect on cherelle survivorship older cherelles had greater survival rates across all developmental stages than younger cherelles. Yield differed between genotype crosses and varied according to the pollen donor used, highlighting the importance of understanding self- and cross-compatibility when selecting clones for cultivation. Pollination intensity had no significant effect on harvested yield, indicating that more rigorous research is needed to identify the pollination intensity required for optimized yield under artificial pollination conditions. We conclude that strategies to enhance flowering, pollination rates, and pollination synchrony while ensuring adequate tree nutrition may increase productivity in cacao. Future research evaluating numerous cacao clones across multiple years and locations may help us to understand the region-specific effects of intensive management strategies on the long-term sustainability of enhancing cacao tree productivity.
Publisher: Springer Science and Business Media LLC
Date: 26-03-2021
Publisher: Wiley
Date: 24-08-2020
Publisher: Wiley
Date: 15-03-2017
DOI: 10.1002/EAP.1491
Abstract: The unique benefits of wild pollinators to the productivity of agricultural crops have become increasingly recognized in recent decades. However, declines in populations of wild pollinator species, largely driven by the conversion of natural habitat to agricultural land and broad-spectrum pesticide use often lead reductions in the provision of pollination services and crop production. With growing evidence that targeted pollinator conservation improves crop yield and/or quality, particularly for pollination specialist crops, efforts are increasing to substitute agriculturally intensive practices with those that alleviate some of the negative impacts of agriculture on pollinators and the pollination services they provide, in part through the provision of suitable pollinator habitat. Further, similarities between the responses of some pollinators and predators to habitat management suggest that efforts to conserve pollinators may also encourage predator densities. We evaluated the effects of one habitat management practice, the addition of cacao fruit husks to a monoculture cacao farm, on the provision of pollination services and the densities of two groups of entomophagous predators. We also evaluated the impacts of cacao fruit husk addition on pollen limitation, by crossing this habitat manipulation with pollen supplementation treatments. The addition of cacao fruit husks increased the number of fruits per tree and along with hand pollination treatments, increased final yields indicating a promotion of the pollination ecosystem service provided by the specialist pollinators, midges. We also found that cacao fruit husk addition increased the densities of two predator groups, spiders and skinks. Further, the conservation of these predators did not inhibit pollination through pollinator capture or deterrence. The findings show that, with moderate habitat management, both pollinator and predator conservation can be compatible goals within a highly specialized plant-pollinator system. The effectiveness of this habitat manipulation may be attributable to the increased availability of alternative habitat and food resources for both pollinators and predators. The results exemplify a win-win relationship between agricultural production and biological conservation, whereby agricultural practices to support vital pollinators and pollination services can increase production as well as support species conservation.
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.TREE.2017.02.012
Abstract: Current evidence suggests that there is a positive relationship between bio ersity and ecosystem functioning, but few studies have addressed tropical ecosystems where the highest levels of bio ersity occur. We develop two hypotheses for the implications of generalizing from temperate studies to tropical ecosystems, and discuss the need for more tropical research.
Publisher: Wiley
Date: 09-02-2011
Publisher: Elsevier BV
Date: 11-2014
Publisher: CSIRO Publishing
Date: 20-02-2023
DOI: 10.1071/CP22306
Abstract: Context Banana production in Australia is in three primary sub-regions within tropical North Queensland and the industry faces a variety of challenges including costs of production, disease and pests, and environmental impacts. The range of soil characteristics and banana leaf nutrient status on banana farms has not previously been systematically described. This knowledge gap makes it difficult to adapt research, management recommendations, and regulations to the needs of the three primary growing sub-regions. Aims In this work, we aimed to identify key soil factors that differentiate growing sub-regions, and provide context for future research and industry regulation. Methods We characterised soil and banana leaf s les from 28 banana farms on soil types accounting for % of Australia’s banana production. Key results and conclusions Variation in soil properties and leaf nutrient concentrations were driven largely by site- (principal component 1 in both cases) and management-related variables (principal component 2 in both cases). Management-related foliar nutrient concentrations did not differ between regions despite differences in the associated soil variables. The most important site characteristics appeared to be soil parent material and climate. The Mareeba sub-region has basaltic soils, low rainfall and temperature, whereas the other two sub-regions are hotter, wetter and have a variety of soil parent materials. Leaf nitrogen concentrations were mostly below the regulated limit for additional nitrogen fertiliser application. Implications Our findings can facilitate sub-region-specific site selection for research, extension, and monitoring and more targeted regulation of banana production- and environment-related issues.
Publisher: The Royal Society
Date: 24-01-2018
Abstract: At local scales, native species can resist invasion by feeding on and competing with would-be invasive species. However, this relationship tends to break down or reverse at larger scales. Here, we consider the role of native species as indirect facilitators of invasion and their potential role in this ersity-driven ‘invasion paradox’. We coin the term ‘native turncoats’ to describe native facilitators of non-native species and identify eight ways they may indirectly facilitate species invasion. Some are commonly documented, while others, such as indirect interactions within competitive communities, are largely undocumented in an invasion context. Therefore, we use models to evaluate the likelihood that these competitive interactions influence invasions. We find that native turncoat effects increase with the number of resources and native species. Furthermore, our findings suggest the existence, abundance and effectiveness of native turncoats in a community could greatly influence invasion success at large scales.
Publisher: Wiley
Date: 02-12-2019
DOI: 10.1002/EAP.2031
Publisher: Oxford University Press (OUP)
Date: 07-2008
Publisher: Springer Science and Business Media LLC
Date: 29-01-2018
DOI: 10.1007/S00248-018-1147-7
Abstract: Parasites often modify host foraging behavior, for ex le, by spurring changes to nutrient intake ratios or triggering self-medication. The gut parasite, Nosema ceranae, increases energy needs of the European or Western honey bee (Apis mellifera), but little is known about how infection affects foraging behavior. We used a combination of experiments and observations of caged and free-flying in idual bees and hives to determine how N. ceranae affects honey bee foraging behavior. In an experiment with caged bees, we found that infected bees with access to a high-quality pollen were more likely to survive than infected bees with access to a lower quality pollen or no pollen. Non-infected bees showed no difference in survival with pollen quality. We then tested free-flying bees in an arena of artificial flowers and found that pollen foraging bees chose pollen commensurate with their infection status twice as many infected bees selected the higher quality pollen than the lower quality pollen, while healthy bees showed no preference between pollen types. However, healthy and infected bees visited sucrose and pollen flowers in the same proportions. Among hive-level observations, we found no significant correlations between N. ceranae infection intensity in the hive and the proportion of bees returning with pollen. Our results indicate that N. ceranae-infected bees benefit from increased pollen quality and will selectively forage for higher quality while foraging for pollen, but infection status does not lead to increased pollen foraging at either the in idual or hive levels.
Publisher: MDPI AG
Date: 08-12-2020
DOI: 10.3390/RS12244008
Abstract: Around the world, the effects of changing plant phenology are evident in many ways: from earlier and longer growing seasons to altering the relationships between plants and their natural pollinators. Plant phenology is often monitored using satellite images and parametric methods. Parametric methods assume that ecosystems have unimodal phenologies and that the phenology model is invariant through space and time. In evergreen ecosystems such as mangrove forests, these assumptions may not hold true. Here we present a novel, data-driven approach to extract plant phenology from Landsat imagery using Generalized Additive Models (GAMs). Using GAMs, we created models for six different mangrove forests across Australia. In contrast to parametric methods, GAMs let the data define the shape of the phenological curve, hence showing the unique characteristics of each study site. We found that the Enhanced Vegetation Index (EVI) model is related to leaf production rate (from in situ data), leaf gain and net leaf production (from the published literature). We also found that EVI does not respond immediately to leaf gain in most cases, but has a two- to three-month lag. We also identified the start of season and peak growing season dates at our field site. The former occurs between September and October and the latter May and July. The GAMs allowed us to identify dual phenology events in our study sites, indicated by two instances of high EVI and two instances of low EVI values throughout the year. We contribute to a better understanding of mangrove phenology by presenting a data-driven method that allows us to link physical changes of mangrove forests with satellite imagery. In the future, we will use GAMs to (1) relate phenology to environmental variables (e.g., temperature and rainfall) and (2) predict phenological changes.
Publisher: Oxford University Press (OUP)
Date: 10-2008
DOI: 10.1603/0046-225X(2008)37[1049:BMFHVH]2.0.CO;2
Abstract: The glassy-winged sharpshooter, Homalodisca vitripennis (Germar), (Hemiptera: Cicadellidae), is a xylophagous leafhopper native to the southeastern United States and northern Mexico, with recent introductions into California, Arizona, French Polynesia, and Hawaii. It is a primary vector of the xylem-limited bacterium, Xylella fastidiosa Wells et al., the causative agent of Pierce's disease of grape, citrus variegated chlorosis, phony peach, and numerous leaf scorch diseases. H. vitripennis uses several hundred species of host plants for feeding, development, and reproduction. Variation in host utilization allows H. vitripennis to respond to diurnal and seasonal changes in its nutrient-poor food source, xylem fluid, as well as changing nutritional requirements of each leafhopper developmental stage. Here we provide a conceptual model that integrates behavior, life history strategies, and their associated risks with the nutritional requirements of adult and nymphal stages of H. vitripennis. The model is a useful heuristic tool that explains patterns of host plant use, describes insect behavior and ecology, suggests new associations among the ecological components, and most importantly, identifies and supports the development of suppression strategies for X. fastidiosa aimed at reducing vector populations through habitat manipulation.
Publisher: Wiley
Date: 12-04-2020
DOI: 10.1002/ECE3.6207
Publisher: Wiley
Date: 09-2012
DOI: 10.1890/12-0188.1
Abstract: Greater resource use by erse communities might result from species occupying complementary niches. Demonstrating niche complementarity among species is challenging, however, due to the difficulty in relating differences between species in particular traits to their use of complementary resources. Here, we overcame this obstacle by exploiting plastic foraging behavior in a community of predatory insects common on Brassica oleracea plants in Washington, USA. These predators complemented one another by partitioning foraging space, with some species foraging primarily along leaf edges and others at leaf centers. We hypothesized that emergent bio ersity effects would occur when predators partitioned foraging space on leaves, but not when spatial complementarity was d ened. Indeed, on intact leaves, edge- and center-foraging predators combined to kill more prey than any single predator species could by itself. These emergent ersity effects, however, disappeared on plants damaged by the caterpillar Plutella xylostella. Caterpillar chew-holes brought edge habitats to the center of leaves, so that all predator species could attack aphids anywhere on plants. With spatial niche differences diminished, there were no benefits of predator ersity the most voracious single predator species killed the most aphids. Thus, caterpillar herbivory determined whether multi-predator-species effects reflected complementarity or species' in idual impacts. Our study provides direct evidence for a causative relationship between niche differentiation and increased resource consumption by erse communities, as revealed by ecological engineers that homogenize the foraging environment.
Publisher: Public Library of Science (PLoS)
Date: 21-07-2016
Publisher: Wiley
Date: 17-11-2021
DOI: 10.1111/ELE.13639
Publisher: Springer Science and Business Media LLC
Date: 28-11-2017
Publisher: Wiley
Date: 02-2012
DOI: 10.1890/11-0399.1
Abstract: Resource consumption often increases with greater consumer bio ersity. This could result either from complementarity among consumers or the inclusion of particular key species, and it is often difficult to differentiate between these two mechanisms. We exploited a simple plant mutation (reduced production of surface waxes) to alter foraging within a community of aphid predators, and thus perhaps shift the nature of resulting predator ersity effects. We found that greater predator species richness dramatically increased prey suppression and plant biomass only on mutant, reduced-wax pea plants (Pisum sativum). On pea plants from a sister line with wild type, waxier plant surfaces, predator species richness did not influence predators' impacts on herbivores or plants. Thus, a change in plant surface structure acted to turn on, or off, the cascading effects of predator ersity. Greater predator richness encouraged higher densities of true predators but did not lead to greater reproduction by a parasitoid, Aphidius ervi fecundity of each natural enemy species was similar for the two plant types. Behavioral observations indicated that although A. ervi was less likely to forage within species-rich predator communities, low-wax plants mitigated this interference by encouraging generally greater A. ervi foraging and thus high rates of aphid dislodgement (aphids dropped from plants to escape A. ervi, but not the other predators). Thus, only species-rich, low-wax plants simultaneously encouraged strong species-specific effects of A. ervi, and strong complementarity among the other predator species. In summary, our study provides evidence that ersity effects in predator assemblages are sensitive to habitat characteristics. Further, we show that a simple plant morphological trait, controlled by a single gene mutation, can dramatically alter the cascading effects of predator species richness on herbivores and plants.
Publisher: Oxford University Press (OUP)
Date: 19-10-2017
DOI: 10.1093/EE/NVX129
Abstract: Tropical forests account for at least 50% of documented ersity, but anthropogenic activities are converting forests to agriculture and urban areas at an alarming rate, with potentially strong effects on insect abundance and ersity. However, the questions remain whether insect populations are uniformly affected by land conversion and if insect conservation can occur in agricultural margins and urban gardens. We compare butterfly populations in tropical secondary forests to those found in sugarcane and urban areas in coastal Guyana and evaluate the potential for particular butterfly communities to inhabit human-modified landscapes. Butterflies were s led for 1 yr using fruit-baited traps in three separated geographical locations on the coast. We used nonmetric multidimensional scaling to assess differences in species assemblages and a generalized linear mixed model to evaluate abundance, species richness, evenness, and ersity. The secondary forests in all three locations supported higher butterfly abundance and ersity than other human-modified areas, although the magnitude of this effect varied by season and location. However, each land use supported its own type of butterfly community, as species composition was different across the three land uses. Sugarcane field margins and urban gardens supported populations of butterflies rarely found in our tropical secondary forest sites. Land management practices that encourage forest conservation along with butterfly-friendly activities in human settlements and agricultural areas could improve butterfly conservation. To this end, butterfly conservation in Guyana and other tropical landscapes would benefit from a shift from inadvertently to actively making the landscape attractive for butterflies.
Publisher: Oxford University Press (OUP)
Date: 02-2009
DOI: 10.1603/022.038.0123
Abstract: Homalodisca vitripennis (Germar) and related species have caused millions of dollars in damage to southern California vineyards in recent years through the vectoring of Pierce's disease. However, the effects of surrounding vegetation on the dispersal and distribution of H. vitripennis are poorly understood. Therefore, the relationship between dispersal rates and patch quality was tested, as well as the basic predictions of the marginal value theorem. Additional experiments were conducted to compare the H. vitripennis distribution in an isolated crape myrtle (Lagerstroemia indica) patch and a L. indica patch bordering two alternative host patches. In mark-release-recapture tests, H. vitripennis dispersed farther from the release point in a patch of low-quality host plants (Prunus persica) than in patches of high-quality host plants (L. indica). In addition, H. vitripennis remained in L. indica patches longer than in P. persica patches and adjusted patch residence times in P. persica in correlation with known changes in plant physiology. These data suggest that H. vitripennis follows the basic predictions of marginal value theorem. In distribution tests, H. vitripennis were more abundant in the patch center than patch edges in the isolated L. indica patch, but in a patch bordering cottonwood (Populus sp.) and peach (P. persica), H. vitripennis numbers were generally higher along the edges of the patch. These data suggest that alternate hosts bordering cropping systems may be important to the spatial dynamics of H. vitripennis. Implications of these spatial observations on the biology of H. vitripennis and potential control methods are discussed.
Publisher: Public Library of Science (PLoS)
Date: 10-10-2011
Publisher: Elsevier BV
Date: 2024
Publisher: Frontiers Media SA
Date: 27-09-2019
Publisher: Frontiers Media SA
Date: 15-05-2019
Publisher: Wiley
Date: 28-07-2017
DOI: 10.1002/ECE3.3250
Publisher: Springer Science and Business Media LLC
Date: 07-2010
DOI: 10.1038/NATURE09183
Abstract: Human activity can degrade ecosystem function by reducing species number (richness) and by skewing the relative abundance of species (evenness). Conservation efforts often focus on restoring or maintaining species number, reflecting the well-known impacts of richness on many ecological processes. In contrast, the ecological effects of disrupted evenness have received far less attention, and developing strategies for restoring evenness remains a conceptual challenge. In farmlands, agricultural pest-management practices often lead to altered food web structure and communities dominated by a few common species, which together contribute to pest outbreaks. Here we show that organic farming methods mitigate this ecological damage by promoting evenness among natural enemies. In field enclosures, very even communities of predator and pathogen biological control agents, typical of organic farms, exerted the strongest pest control and yielded the largest plants. In contrast, pest densities were high and plant biomass was low when enemy evenness was disrupted, as is typical under conventional management. Our results were independent of the numerically dominant predator or pathogen species, and so resulted from evenness itself. Moreover, evenness effects among natural enemy groups were independent and complementary. Our results strengthen the argument that rejuvenation of ecosystem function requires restoration of species evenness, rather than just richness. Organic farming potentially offers a means of returning functional evenness to ecosystems.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Wiley
Date: 08-2016
DOI: 10.1890/15-0884.1
Abstract: Cannibalism is a widespread behavior, and evidence is abundant for transmission from infected victims to susceptible cannibals in many parasite-host systems. Current theory suggests that cannibalism generally impedes disease spread, because each victim is usually consumed by a single cannibal. Thus, cannibalism merely transfers pathogens from one in idual to another without spreading infections to additional hosts. This assumes that cannibalism is the only mode of transmission and that the host population is homogenous. However, host developmental stages are a key determinant of both cannibal-victim and host-pathogen interactions. We suggest that multiple modes of pathogen transmission can interact through host stage structure. We show theoretically that cannibalism can enhance disease spread by consistently transferring infections from low quality to high quality hosts that are more infectious via horizontal transmission. We review empirical evidence for the generality of key conditions required for this process, and analyze the implications for the evolution of transmission through cannibalism. More generally, our theory promotes the consideration of multiple transmission pathways when studying parasite-host systems, and advances a useful intuition for assessing whether or not such pathways may be mutually augmentative.
Publisher: Springer Science and Business Media LLC
Date: 26-01-2018
DOI: 10.1038/S41598-018-19985-9
Abstract: We evaluate potential warning signals that may aid in identifying the proximity of ecological communities to bio ersity thresholds from habitat loss—often termed “tipping points”—in tropical forests. We used datasets from studies of Neotropical mammal, frog, bird, and insect communities. Our findings provide only limited evidence that an increase in the variance (heteroskedasticity) of bio ersity-related parameters can provide a general warning signal of impending threshold changes in communities, as forest loss increases. However, such an apparent effect was evident for hibians in the Brazilian Atlantic Forest and Amazonian mammal and bird communities, suggesting that impending changes in some species assemblages might be predictable. We consider the potential of such warning signs to help forecast drastic changes in bio ersity.
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.COIS.2017.07.006
Abstract: Global climate change is often expected to disrupt biological control. Predicting the effects of climate change on biological control, and identifying natural enemies that will thrive in future climate scenarios, is thus essential to ensure agricultural sustainability. To promote biological control under climate change, land managers should prioritise the conservation of natural enemy ersity to ensure some effective natural enemies are always present despite often-unpredictable climate scenarios. In addition, ecophysiological and habitat domain models should be combined to predict climate change-induced shifts in predation by erse predator communities. Finally, insights from land managers during extreme weather events, such as droughts and heat waves, may be invaluable in the effort to identify key biological control agents for future scenarios.
Publisher: The Royal Society
Date: 20-09-2017
Abstract: Animals embedded between trophic levels must simultaneously balance pressures to deter predators and acquire resources. Venomous animals may use venom toxins to mediate both pressures, and thus changes in this balance may alter the composition of venoms. Basic theory suggests that greater exposure to a predator should induce a larger proportion of defensive venom components relative to offensive venom components, while increases in arms races with prey will elicit the reverse. Alternatively, reducing the need for venom expenditure for food acquisition, for ex le because of an increase in scavenging, may reduce the production of offensive venom components. Here, we investigated changes in scorpion venom composition using a mesocosm experiment where we manipulated scorpions' exposure to a surrogate vertebrate predator and live and dead prey. After six weeks, scorpions exposed to surrogate predators exhibited significantly different venom chemistry compared with naive scorpions. This change included a relative increase in some compounds toxic to vertebrate cells and a relative decrease in some compounds effective against their invertebrate prey. Our findings provide, to our knowledge, the first evidence for adaptive plasticity in venom composition. These changes in venom composition may increase the stability of food webs involving venomous animals.
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.JENVMAN.2019.109430
Abstract: In Australia, and other parts of the world, tower infrastructure in electricity transmission networks are nearing the end of their asset life. In changing economic, political and regulatory environments Transmission Network Service Providers are implementing new approaches to asset management and reinvestment, such as refurbishment to extend the life of existing assets, instead of replacement. As part of these refurbishment efforts, abrasive blasting and recoating is being employed to remove corrosion and extend the life of steel electricity transmission towers. New controls and procedures have been developed to manage the most likely impacts associated with the abrasive blasting of transmission towers. However, little or no data have been available on the environmental impacts of abrasive blasting or the effectiveness of management procedures currently being used to mitigate potential adverse environmental impacts.We conducted an integrated study on the impacts of abrasive blasting, which brought together on-site research modelling and controlled laboratory trials. The study was undertaken during a transmission tower refurbishment project within the World Heritage listed Wet Tropics Region in Queensland, Australia. Measured metal deposition around towers due to blasting, was primarily as large particles (>PM10) at 12-30 m from the tower. Soil concentrations of metals were highest under towers, with a small number of s les showing elevated zinc at 12-30 m. The presence of spent abrasive media and dust on the geofabric material used under the towers and up to 15 m from the tower base, as part of control measures used to contain the abrasive products, indicates that deposition also occurs between 0 and 12 m from the tower.The potential impacts of the abrasive blasting technique on plants and invertebrates appear to be low. Five species of tropical rainforest tree seedlings exposed to abrasive blasting dust at worst-case levels had no negative impact on physiological performance or plant health. This research will assist Transmission Network Service Providers and other operators of corroded linear infrastructure to plan and implement mitigating management actions and procedures during abrasive blasting projects and assist regulators and the community to better understand the impacts of the practice.
Publisher: Wiley
Date: 10-02-2022
DOI: 10.1002/EAP.2523
Abstract: Recent foodborne illness outbreaks have heightened pressures on growers to deter wildlife from farms, jeopardizing conservation efforts. However, it remains unclear which species, particularly birds, pose the greatest risk to food safety. Using ,000 pathogen tests and 1565 bird surveys covering 139 bird species from across the western United States, we examined the importance of 11 traits in mediating wild bird risk to food safety. We tested whether traits associated with pathogen exposure (e.g., habitat associations, movement, and foraging strategy) and pace‐of‐life (clutch size and generation length) mediated foodborne pathogen prevalence and proclivities to enter farm fields and defecate on crops. C ylobacter spp. were the most prevalent enteric pathogen (8.0%), while Salmonella and Shiga‐toxin producing Escherichia coli (STEC) were rare (0.46% and 0.22% prevalence, respectively). We found that several traits related to pathogen exposure predicted pathogen prevalence. Specifically, C ylobacter and STEC‐associated virulence genes were more often detected in species associated with cattle feedlots and bird feeders, respectively. C ylobacter was also more prevalent in species that consumed plants and had longer generation lengths. We found that species associated with feedlots were more likely to enter fields and defecate on crops. Our results indicated that canopy‐foraging insectivores were less likely to deposit foodborne pathogens on crops, suggesting growers may be able to promote pest‐eating birds and birds of conservation concern (e.g., via nest boxes) without necessarily compromising food safety. As such, promoting insectivorous birds may represent a win‐win‐win for bird conservation, crop production, and food safety. Collectively, our results suggest that separating crop production from livestock farming may be the best way to lower food safety risks from birds. More broadly, our trait‐based framework suggests a path forward for co‐managing wildlife conservation and food safety risks in farmlands by providing a strategy for holistically evaluating the food safety risks of wild animals, including under‐studied species.
Publisher: Oxford University Press (OUP)
Date: 08-2009
DOI: 10.1603/022.038.0411
Abstract: In the southeast United States, a field of peanuts, Arachis hypogaea L., is often closely associated with a field of cotton, Gossypium hirsutum L. The objective of this 4-yr on-farm study was to examine and compare the spatiotemporal patterns and dispersal of the southern green stink bug, Nezara viridula L., and the brown stink bug, Euschistus servus (Say), in six of these peanut-cotton farmscapes. GS(+) Version 9 was used to generate interpolated estimates of stink bug density by inverse distance weighting. Interpolated stink bug population raster maps were constructed using ArcMap Version 9.2. This technique was used to show any change in distribution of stink bugs in the farmscape over time. SADIE (spatial analysis by distance indices) methodology was used to examine spatial aggregation of in idual stink bug species and spatial association of the two stink bug species in the in idual crops. Altogether, the spatiotemporal analyses for the farmscapes showed that some N. viridula and E. servus nymphs and adults that develop in peanuts disperse into cotton. When these stink bugs disperse from peanuts into cotton, they aggregate in cotton at the interface, or common boundary, of the two crops while feeding on cotton bolls. Therefore, there is a pronounced edge effect observed in the distribution of stink bugs as they colonize the new crop, cotton. The driving force for the spatiotemporal distribution and dispersal of both stink bug species in peanut-cotton farmscapes seems to be availability of food in time and space mitigated by landscape structure. Thus, an understanding of farmscape ecology of stink bugs and their natural enemies is necessary to strategically place, in time and space, biologically based management strategies that control stink bug populations while conserving natural enemies and the environment and reducing off-farm inputs.
Publisher: Wiley
Date: 09-2012
DOI: 10.1890/12-0110.1
Abstract: Healthy ecosystems include many species (high richness) with similar abundances (high evenness). Thus, both aspects of bio ersity are worthy of conservation. Simultaneously conserving richness and evenness might be difficult, however, if, for ex le, the restoration of previously absent species to low densities brings a cost in reduced evenness. Using meta-analysis, we searched for benefits to bio ersity following adoption of two common land-management schemes: the implementation of organic practices by farmers and of controlled burning by natural-land managers. We used rarefaction to eliminate s ling bias in all of our estimates of richness and evenness. Both conservation practices significantly increased evenness and overall abundance across taxonomic classifications (arthropods, birds, non-bird vertebrates, plants, soil organisms). Evenness and richness varied independently, leading to no richness-evenness correlation and no significant overall change in richness. Demonstrating the importance of rarefaction, analyses of raw data that did not receive rarefaction indicated misleadingly strong benefits of organic agriculture and burning for richness while underestimating true gains in evenness. Both organic farming and burning favored species that were not numerically dominant, re-balancing communities as uncommon species gained in iduals. Our results support the assertion that richness and evenness capture separate facets of bio ersity, each needing in idual attention during conservation.
Publisher: Wiley
Date: 12-2018
DOI: 10.1002/ECE3.4732
Publisher: Wiley
Date: 16-10-2019
DOI: 10.1111/ELE.13406
Abstract: Bees are ecosystem service providers that are globally threatened by losses of plant ersity. However, effects of multi-species floral displays on bees in agro-ecosystems with variable landscape context remain poorly understood, hindering pollinator conservation tactics. We addressed this knowledge gap through a novel application of the modified Price equation to evaluate responses of bees to erse floral communities on 36 farms in Washington, USA, over 3 years. We found that floral richness, not floral identity, was the best predictor of floral visits by bees. However, the benefits of regionally rare floral species (i.e. plants found at relatively few sites) were only fully realised when farms were embedded in erse landscapes. Our analysis used the modified Price equation to demonstrate that plant ersity, rather than specific plant species, promotes pollinator visitation, and that erse landscapes promote the response of pollinators to regionally rare plant species.
Publisher: Wiley
Date: 22-03-2017
DOI: 10.1111/BTP.12405
No related grants have been discovered for Tobin Northfield.