Urbanization versus other land use: Diverging effects on dragonfly communities in Germany

Drivers of Insect Community Change along the Margins of Mountain Streams in Serra da Estrela Natural Park (Portugal)

Mountain ecosystems are important biodiversity hotspots and valuable natural laboratories to study community assembly processes. Here, we analyze the diversity patterns of butterflies and odonates in a mountainous area of high conservation value-Serra da Estrela Natural Park (Portugal)-and we assess the drivers of community change for each of the two insect groups. The butterflies and odonates were sampled along 150 m transects near the margins of three mountain streams, at three elevation levels (500, 1000, and 1500 m). We found no significant differences in odonate species richness between elevations, but marginal differences (p = 0.058) were found for butterflies due to the lower number of species at high altitudes. Both insect groups showed significant differences in beta diversity (βtotal) between elevations, with species richness differences being the most important component for odonates (βrich = 55.2%), while species replacement drove the changes between butterfly assemblages (βrepl = 60.3%). Climatic factors, particularly those depicting harsher conditions of temperature and precipitation, were the best predictors of total beta diversity (βtotal) and its components (βrich, βrepl) for the two study groups. The study of insect biodiversity patterns in mountain ecosystems and of the role played by different predictors contribute to further our understanding on the community assembly processes and may help to better predict environmental change impacts on mountain biodiversity.

Climate change aggravates non-target effects of pesticides on dragonflies at macroecological scales

Critical gaps in understanding how species respond to environmental change limit our capacity to address conservation risks in a timely way. Here, we examine the direct and interactive effects of key global change drivers, including climate change, land use change, and pesticide use, on persistence of 104 odonate species between two time periods (1980-2002 and 2008-2018) within 100 × 100 km quadrats across the USA using phylogenetic mixed models. Non-target effects of pesticides interacted with higher maximum temperatures to contribute to odonate declines. Closely related species responded similarly to global change drivers, indicating a potential role of inherited traits in species' persistence or decline. Species shifting their range to higher latitudes were more robust to negative impacts of global change drivers generally. Inherited traits related to dispersal abilities and establishment in new places may govern both species' acclimation to global change and their abilities to expand their range limits, respectively. This work is among the first to assess effects of climate change, land use change, and land use intensification together on Odonata, a significant step that improves understanding of multispecies effects of global change on invertebrates, and further identifies conditions contributing to global insect loss.

The Role of Community Science in Entomology

Community (or citizen) science, the involvement of volunteers in scientific endeavors, has a long history. Over the past few centuries, the contributions of volunteers to our understanding of patterns and processes in entomology have been inspiring. From the collation of large-scale and long-term data sets, which have been instrumental in underpinning our knowledge of the status and trends of many insect groups, to action, including species management, whether for conservation or control, community scientists have played pivotal roles. Contributions, such as pest monitoring by farmers and species discoveries by amateur naturalists, set foundations for the research engaging entomologists today. The next decades will undoubtedly bring new approaches, tools, and technologies to underpin community science. The potential to increase inclusion within community science is providing exciting opportunities within entomology. An increase in the diversity of community scientists, alongside an increasing taxonomic and geographic breadth of initiatives, will bring enormous benefits globally for people and nature.

Adult damselflies as possible regulators of mosquito populations in urban areas

BACKGROUND

Dragonfly and damselfly larvae have been considered as possible biocontrol agents against young instars of mosquito vectors in urban environments. Yet our knowledge about adult odonate predation against mosquito adults is scarce. We quantified daily and annual predation rates, consumption rates and prey preferences of adult Hetaerina vulnerata male damselflies in an urban park. A focus on predation of mosquito species was provided, quantified their arbovirus (dengue, chikungunya and Zika) infection rates and biting activity.

RESULTS

Foraging times of H. vulnerata overlapped with those of the maximum activity of hematophagous mosquitoes. The most consumed preys were Diptera and Hymenoptera and, in lower quantities, Hemiptera, Coleoptera, Trichoptera, Psocoptera and Neuroptera. Of note, 7% of the diet was represented by hematophagous dipterans, with 2.4% being Aedes aegypti and Aedes albopictus. Prey abundance in the diet coincided with that of the same species in the environment. The arboviral infection rate (dengue, chikungunya and Zika) was 1.6% for A. aegypti and A. albopictus. The total biting rate of these mosquito vectors was 16 bites per person per day, while the annual rate of infectious bites was 93.4.

CONCLUSION

Although 2.4% for both Aedes species seems a low consumption, considering the presence of 12 odonate species at the park, it can be argued that adult odonates may play a relevant role as mosquito vector regulators, therefore impacting the spread of mosquito-borne diseases. Our study outlines the need for further research on the topic of the possible role of adult odonates for mosquito biocontrol. © 2021 Society of Chemical Industry.

Effects of Landscape Patterns and Their Changes to Species Richness, Species Composition, and the Conservation Value of Odonates (Insecta)

Simple Summary

In this study, we aimed to evaluate the relationship between human transformations of land use/land cover and adult dragonfly diversity. Based on previous studies, we assumed that with increasing rates of environmental degradation and declining levels of naturalness, the representation of species with high conservation value would significantly decrease, which, however, would not affect the regional alpha diversity. Our results have shown that species richness did not correspond to habitat naturalness, but the occurrence of endangered species was significantly positively correlated with increasing naturalness; thus, habitat degradation and/or the level of naturalness significantly affected species composition, while species richness remained unchanged. Based on our analyses, it is evident that most natural areas, and therefore the least affected areas, provide suitable conditions for the largest number of endangered species. This research extends our knowledge about the impact of human activities, especially the conversion and degradation of habitats, on the composition of odonates and freshwater animals at the regional scale.

Abstract

Understanding the impact of the changing proportion of land-use patterns on species diversity is a critical issue in conservation biology, and odonates are good bioindicators of these environmental changes. Some freshwater ecosystems that have been modified due to human activities can serve as important secondary habitats for odonate assemblages; however, the majority of studies addressing the value of secondary habitats in industrial and urban areas for adult dragonfly diversity have been limited to the local scale, and the value of such habitats for gamma diversity is still unclear. The aim of this study was to determine the relationship between human transformations of land use/land cover and dragonfly diversity. We interpolated the information based on dragonfly occurrence per grid cell and land cover data, indicating naturalness and degradation in 677 grid cells in the Czech Republic. Species richness did not correspond to habitat naturalness, but the occurrence of endangered species was significantly positively correlated with increasing naturalness; thus, habitat degradation and/or the level of naturalness significantly affected species composition, while species richness remained unchanged. Threatened species that occur predominantly in natural areas and threatened species with a dominant occurrence in degraded squares were also separated, which indicated that the conservation of the latter should be prioritised.

A Review of the Impacts and Opportunities for African Urban Dragonflies

Simple Summary

The expansion of urban areas in combination with climate change places great pressure on species found in freshwater habitats. Dragonflies are iconic freshwater organisms due to their large body sizes and striking coloration. They have been widely used to indicate the impacts of natural and human-mediated activities on freshwater communities, while also indicating the mitigation measures required to ensure their conservation. Here, we review the major threats to dragonflies in southern Africa, specifically those in urban areas. We also provide information on effective mitigation measures to protect dragonflies and other aquatic insects in urban spaces. Using three densely populated areas as case studies, we highlight some of the greatest challenges for dragonflies in South Africa. More importantly, we give a summary of current mitigation measures which have maintained dragonflies in urban spaces. In addition to these mitigation measures, public involvement and raising awareness contribute greatly to the common cause of protecting dragonflies around us.

Abstract

Urban settlements range from small villages in rural areas to large metropoles with densely packed infrastructures. Urbanization presents many challenges to the maintenance of freshwater quality and conservation of freshwater biota, especially in Africa. There are many opportunities as well, particularly by fostering contributions from citizen scientists. We review the relationships between dragonflies and urbanization in southern Africa. Shifts in dragonfly assemblages indicate environmental change, as different species are variously sensitive to abiotic and biotic water and bank conditions. They are also conservation umbrellas for many other co-occurring species. Major threats to southern African dragonflies include increasing infrastructure densification, frequent droughts, habitat loss, pollution, and invasive alien vegetation. Mitigation measures include implementation of conservation corridors, maintenance of healthy permanent ponds, pollution reduction, and removal of invasive alien trees. Citizen science is now an important approach for supplementing and supporting professional scientific research.

Effects of urbanization on the fauna of Odonata on the coast of southern Brazil

Abstract: Urbanization significantly increases the rates of environmental disturbance, being one of the main causes of habitat loss and biodiversity. The growing trend of converting the natural landscape into areas for real estate speculation in the coastal region of the southernmost part of Brazil is a current concern, as the region is home to unique ecosystems, such as dunes, wetlands and large brackish lagoons. As they are organisms sensitive to environmental changes, variations in the structure of Odonata communities are used as indicators of habitat quality reflecting the human impact on the environment. Here we assessed how the Odonata community is affected by the growing urbanization around natural ponds on the coast of the state of Rio Grande do Sul, testing the hypothesis that the increase in the percentage of urbanization negatively influences the Odonata community, following the same pattern found for other groups of invertebrates. The collections took place in 28 coastal ponds, which were classified as urbanized and non-urbanized based on the surrounding ground cover. Anisoptera’s richness, abundance and composition were influenced by urbanization, but the same was not found for Zygoptera. The analysis of indicator species specifies three species associated with non-urbanized areas: Erythrodiplax sp.1, Erythemis credula and Telebasis corallina. Our study highlights the importance of Odonata as organisms that indicate environmental integrity and reinforces the need for urban planning strategies that favor the conservation and maintenance of the environments affected by urbanization.

Towards Global Volunteer Monitoring of Odonate Abundance

Insects are reportedly experiencing widespread declines, but we generally have sparse data on their abundance. Correcting this shortfall will take more effort than professional entomologists alone can manage. Volunteer nature enthusiasts can greatly help to monitor the abundance of dragonflies and damselflies (Odonata), iconic freshwater sentinels and one of the few nonpollinator insect groups appreciated by the public and amenable to citizen science. Although counting individual odonates is common in some locations, current data will not enable a global perspective on odonate abundance patterns and trends. Borrowing insight from butterfly monitoring efforts, we outline basic plans for a global volunteer network to count odonates, including organizational structure, advertising and recruiting, and data collection, submission, and synthesis. We hope our proposal serves as a catalyst for richer coordinated efforts to understand population trends of odonates and other insects in the Anthropocene.

Evaluation of Land Intensive Use in Shanghai Pilot Free Trade Zone

Free trade zones represent an important system innovation space to realize economic agglomeration advantages with high-level openings. However, its evaluation of land intensive use has not received enough attention. The goal of this paper is to build a land use performance evaluation index system in line with the development trend of industrial economy and the characteristics of mixed land use in the free trade zones. An evaluation index system is constructed based on the three factors of land use status, land use efficiency and pilot free trade zone influence. Using the Delphi method and the entropy method, an empirical evaluation of the intensive land use level in the Shanghai Pilot Free Trade Zone is conducted. The results show the following: (1) integrating new indicators such as the free trade zone influence, social and ecological benefits into the evaluation index system show a characteristic and innovative land use evaluation; (2) in terms of the level of intensive land use, the Waigaoqiao Free Trade Zone has the highest intensity, followed by the Yangshan Free Trade Port Zone, and the Pudong Airport Comprehensive Free Trade Zone has the lowest intensity; and (3) development time, degree of land use, differences in leading functions, industrial land structures, and the diversification of employment structures are important factors that influence the differences in the levels of intensive land use in the Shanghai Pilot Free Trade Zone. This study also expands the performance evaluation of industrial land to the performance evaluation of construction land and provides references for industrial transformation and urban renewal of the Shanghai Pilot Free Trade Zone.