A simultaneous assessment of multiple ecosystem services and disservices in vineyards and orchards on Terceira Island, Azores

Monitoring ecosystem processes resulting in ecosystem services (ESs) and disservices (EDs) is crucial in agricultural ecosystems. Traditionally, ESs/EDs provided by arthropods have been estimated indirectly by measuring arthropod abundance and diversity, overlooking the recognised limitations of such approach. Using a consistent methodology based on the sentinel approach, we quantified the intensity of five ecological processes leading to four ESs and two EDs in vineyards and citrus orchards on Terceira Island, Azores. We assessed herbivory rates on lettuce plants (ED), predation rates on green plasticine caterpillars by vertebrates and invertebrates (ES), the intensity of insect pollination on strawberry plants (ES), the rates of predation on wheat and dandelion seeds (ED and ES, respectively) by rodents and invertebrates, and decomposition rates using tea and rooibos leaves (ES). Herbivory rates after 2 weeks were significantly lower in vineyards (mean ± SD; 0.5 ± 0.6%) than in citrus orchards (3.6 ± 2.9%). Vertebrate predation rates in vineyards (4.0 ± 13.6% d⁻¹) were significantly higher than in citrus orchards (2.4 ± 10.7% d⁻¹), while no differences were observed for overall and invertebrate predation rates. Pollination efficiency in vineyards (214.5 ± 23.9 seeds/fruit) was significantly higher than in citrus orchards (162.0 ± 14.7 seeds/fruit). Seed predation rates were higher, although not significantly so, in citrus orchards (2.0 ± 5.8% d⁻¹) than in vineyards (0.3 ± 0.8% d⁻¹). Decomposition was significantly higher on tea than on rooibos leaves, both in vineyards (1.15 ± 0.11 g vs. 0.72 ± 0.16 g) and citrus orchards (1.34 ± 0.06 g vs. 0.78 ± 0.13 g); no differences between mass loss in the two habitats were observed. Our results demonstrated the suitability of simple, direct monitoring tools for a quantitative comparison of agricultural habitats, confirm that landscape complexity does not always support ESs, and that the same agro-ecosystem characteristics that support ESs could occasionally also favour EDs.This work was financed by FEDER (European Regional Development Fund) in 85% and by Azorean Public Funds by 15% through Operational Program Azores 2020, under the project AGRO-ECOSERVICES (ACORES-01-0145-FEDER-000073).info:eu-repo/semantics/publishedVersio

The history of degenerate (bipartite) extremal graph problems

This paper is a survey on Extremal Graph Theory, primarily focusing on the case when one of the excluded graphs is bipartite. On one hand we give an introduction to this field and also describe many important results, methods, problems, and constructions.Comment: 97 pages, 11 figures, many problems. This is the preliminary version of our survey presented in Erdos 100. In this version 2 only a citation was complete

A survey of χ\chi-boundedness

If a graph has bounded clique number, and sufficiently large chromatic number, what can we say about its induced subgraphs? Andr\'as Gy\'arf\'as made a number of challenging conjectures about this in the early 1980's, which have remained open until recently; but in the last few years there has been substantial progress. This is a survey of where we are now

Understanding Habitat Effects on Pollinator Guild Composition in New York State and the Importance of Community Science Involvement in Understanding Species Distributions

Concerns regarding pollinator declines have grown recently, yet detection of changes in species richness, abundance, and guild composition are inhibited by a lack of data over space and time. New York State initiated surveys for pollinators in multiple ecoregions and habitat types across NYS to assess current distributions as rarity measures. Sampling took place from May–Aug 2018 with contributions by community scientists. Pollinator richness was influenced by habitat (meadow, roadside, wetland, forest), floral presence and abundance, and interactions between floral abundance and month, but not ecoregion. Research to date on data collection quality by community science volunteers has provided mixed results, thus, data collected by volunteers was evaluated relative to paid field biologists. Results suggest volunteers added valuable data to that collected by paid biologists. Volunteers (both via field collection and digital submissions) increased quantified species richness, of both common and species of conservation interest, and informed where species occurred. This research informs development and implementation of conservation practices

LD50 values may be misleading predictors of neonicotinoid toxicity across different bee species

The importance of not only honey bees (Apis mellifera) but also other non-managed bee species and their pollination services has come to light with their recently reported declines. One contributing factor in these declines is thought to be sub-lethal exposure to neonicotinoid insecticides such as thiacloprid. However, current government regulatory agencies do not require the assessment of insecticide toxicity on bee species other than the honey bee, even though previous studies have demonstrated that sensitivity to insecticides is not likely to be generalizable from honey bees to non-managed bee species. Replicating standardized protocols and testing five different doses of thiacloprid on individual caged bees, we assessed the acute contact toxicity by calculating mortality and the lethal dose (LD50) value for three bee species with different life history traits: Apis mellifera, Bombus terrestris, and Osmia bicornis. We found that Apis mellifera and Osmia bicornis had significantly higher mortality in comparison to Bombus terrestris, but there was no dose-dependent response for any of the three bee species. Bee size and sex were also not useful predictors of thiacloprid toxicity. These results suggest that solely relying on LD50 values, especially when they do not produce a dose-dependent response, may be misleading when assessing insecticide toxicity risk for honey bees and other non-managed bee species

Direct and indirect controls on bee community composition

Bees are important pollinators, critical for the continued survival of plants in both natural and agricultural ecosystems. Diverse bee communities have been shown to increase richness in plant communities and plant reproduction depends upon bee community richness. Yet there is growing concern that pollinators, especially bees, are declining globally. This dissertation focuses on evaluating the mechanisms responsible for bee community composition in order to promote bee conservation in natural systems and their restoration in human-dominated urban and agricultural landscapes. Bee populations are impacted directly by three things: floral resources, nesting resources and risk, primarily from natural enemies. Bees are indirectly affected by abiotic factors, like climate, that influence both their behavior and the resources available. Relationships between bees and their floral resources have received the most attention, providing evidence of floral resources structuring bee communities and controlling bee population dynamics. The first investigation described in this dissertation determines the universality of this relationship through a meta-analysis of the effects of plant community composition on bee community composition. The second and third investigations described in this dissertation focus on the management of two species of cavity nesting bees, Osmia cornifrons and O. taurus, in terms of their utilization of artificial nesting substrate (Chapter 3) and the influence of temperature on their emergence timing (Chapter 4). This information is useful whether they need to be managed for their pollination services or to reduce their impacts as non-native species. The overall aim of this dissertation work is to promote bee restoration and conservation by adding to the understanding of the roles of both direct and indirect controls on bee community composition

Diversidad de abejas silvestres en huertas de Madrid, buscando caminos para una transición agroecológica

Farms and its different management practices have substantial effects on biodiversity, with the consequent impact on the supply of certain ecosystem services such us pollination. Wild bees provide pollination services in small scale horticultural farming, which is key element to determine and improve farm production but also to the maintenance of ecosystem´s diversity. In this study we aim to identify which species of wild bees can be found in small horticultural farms in the northern area of Madrid and to analyse how its diversity is influence by agricultural practices and by the elements of the surrounding landscape. In addition, we deepen in the agricultural practices carried out in small scale horticultural production and farmer’s perception about pollination importance. By doing so, we aim to get a perspective of the agroecological transition in Madrid and the management of agroecological practices from farmer´s perspective. To characterize the farms and to obtained information about the agricultural practices we carried out semi-structured interviews. Farmers showed awareness about the importance of pollination and wild bee communities for the development of their crops and other wild plants. Their perception on the effect of agricultural practices on pollinators match with the scientific data, being wild flowers, aromatic plants and the conservation of natural edges the practices that most influences pollinators. Farm management is rather similar within each other since all of them are small horticultural producers located in the same area. In order to quantify the differences within farms, we gave quantitative scores to the agricultural practices measuring impact and time of application. A total of 16 horticultural farms were sample using the pan-trapping method during the flowering period of the horticultural plants to collect wild bees. Surrounding landscape composition was analysing with satellite imagery to identify the different elements present around the farms. In total, 109 wild bee species were identified with individuals from the six bee families present on the Iberian Peninsula. The most predominant genera are Lasioglossum, belonging to the Halictidae family, which are characterized by nesting in soils. The results indicated that the element with most influence on wild bee species richness is sparsely vegetated soil, followed by the presence of forest areas. These areas might correspond to potential areas of nesting sites for wild bees. This thesis aims to contribute to better understanding of the agoecological transition in Madrid and to highlighted the importance of this small scale farming areas to promote biodiversity and landscape diversity

Uncertainties in the value and opportunity costs of pollination services

Pollination is an ecosystem service that directly contributes to agricultural production, and can therefore provide a strong incentive to conserve natural habitats that support pollinator populations. However, we have yet to provide consistent and convincing pollination service valuations to effectively slow the conversion of natural habitats. We use coffee in Kodagu, India, to illustrate the uncertainties involved in estimating costs and benefits of pollination services. First, we fully account for the benefits obtained by coffee agroforests that are attributable to pollination from wild bees nesting in forest habitats. Second, we compare these benefits to the opportunity cost of conserving forest habitats and forgoing conversion to coffee production. Throughout, we systematically quantify the uncertainties in our accounting exercise and identify the parameters that contribute most to uncertainty in pollination service valuation. We find the value of pollination services provided by one hectare of forest to be 25% lower than the profits obtained from converting that same surface to coffee production using average values for all parameters. However, our results show this value is not robust to moderate uncertainty in parameter values, particularly that driven by variability in pollinator density. Synthesis and applications. Our findings emphasize the need to develop robust estimates of both value and opportunity costs of pollination services that take into account landscape and management variables. Our analysis contributes to strengthening pollination service arguments used to help stakeholders make informed decisions on land use and conservation practices. © 2019 The Authors. Journal of Applied Ecology © 2019 British Ecological Societ

The potential of electricity transmission corridors in forested areas as bumblebee habitat

Declines in pollinator abundance and diversity are not only a conservation issue, but also a threat to crop pollination. Maintained infrastructure corridors, such as those containing electricity transmission lines, are potentially important wild pollinator habitat. However, there is a lack of evidence comparing the abundance and diversity of wild pollinators in transmission corridors with other important pollinator habitats. We compared the diversity of a key pollinator group, bumblebees (Bombus spp.), between transmission corridors and the surrounding semi-natural and managed habitat types at 10 sites across Sweden’s Uppland region. Our results show that transmission corridors have no impact on bumblebee diversity in the surrounding area. However, transmission corridors and other maintained habitats such as roadsides have a level of bumblebee abundance and diversity comparable to semi-natural grasslands and host species that are important for conservation and ecosystem service provision. Under the current management regime, transmission corridors already provide valuable bumblebee habitat, but given that host plant density is the main determinant of bumblebee abundance, these areas could potentially be enhanced by establishing and maintaining key host plants. We show that in northern temperate regions the maintenance of transmission corridors has the potential to contribute to bumblebee conservation and the ecosystem services they providePeer reviewe