Worldwide decline of the entomofauna: A review of its drivers

Does organic farming benefit biodiversity

Ecosystem services are the benefits obtained from the environment that increase human well-being. Economic valuation is conducted by measuring the human welfare gains or losses that result from changes in the provision of ecosystem services. Bats have long been postulated to play important roles in arthropod suppression, seed dispersal, and pollination; however, only recently have these ecosystem services begun to be thoroughly evaluated. Here, we review the available literature on the ecological and economic impact of ecosystem services provided by bats. We describe dietary preferences, foraging behaviors, adaptations, and phylogenetic histories of insectivorous, frugivorous, and nectarivorous bats worldwide in the context of their respective ecosystem services. For each trophic ensemble, we discuss the consequences of these ecological interactions on both natural and agricultural systems. Throughout this review, we highlight the research needed to fully determine the ecosystem services in question. Finally, we provide a comprehensive overview of economic valuation of ecosystem services. Unfortunately, few studies estimating the economic value of ecosystem services provided by bats have been conducted to date; however, we outline a framework that could be used in future studies to more fully address this question. Consumptive goods provided by bats, such as food and guano, are often exchanged in markets where the market price indicates an economic value. Nonmarket valuation methods can be used to estimate the economic value of nonconsumptive services, including inputs to agricultural production and recreational activities. Information on the ecological and economic value of ecosystem services provided by bats can be used to inform decisions regarding where and when to protect or restore bat populations and associated habitats, as well as to improve public perception of bats.

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Ecosystem services provided by bats

The impacts of agricultural land use are far-reaching and extend to areas outside production. This paper provides an overview of the ecological status of agricultural systems across the European Union in the light of recent policy changes. It builds on the previous review of 2001 devoted to the impacts of agricultural intensification in Western Europe. The focus countries are the UK, The Netherlands, Boreal and Baltic countries, Portugal, Hungary and Romania, representing a geographical spread across Europe, but additional reference is made to other countries. Despite many adjustments to agricultural policy, intensification of production in some regions and concurrent abandonment in others remain the major threat to the ecology of agro-ecosystems impairing the state of soil, water and air and reducing biological diversity in agricultural landscapes. The impacts also extend to surrounding terrestrial and aquatic systems through water and aerial contamination and development of agricultural infrastructures (e.g. dams and irrigation channels). Improvements are also documented regionally, such as successful support of farmland species, and improved condition of watercourses and landscapes. This was attributed to agricultural policy targeted at the environment, improved environmental legislation, and new market opportunities. Research into ecosystem services associated with agriculture may provide further pressure to develop policy that is targeted at their continuous provisioning, fostering motivation of land managers to continue to protect and enhance them.

Ecological impacts of early 21st century agricultural change in Europe: a review. J Environ Manag

Ecosystem services are natural processes that benefit humans. Birds contribute the four types of services recognized by the UN Millennium Ecosystem Assessment-provisioning, regulating, cultural, and supporting services. In this review, we concentrate primarily on supporting services, and to a lesser extent, provisioning and regulating services. As members of ecosystems, birds play many roles, including as predators, pollinators, scavengers, seed dispersers, seed predators, and ecosystem engineers. These ecosystem services fall into two subcategories: those that arise via behavior (like consumption of agricultural pests) and those that arise via bird products (like nests and guano). Characteristics of most birds make them quite special from the perspective of ecosystem services. Because most birds fly, they can respond to irruptive or pulsed resources in ways generally not possible for other vertebrates. Migratory species link ecosystem processes and fluxes that are separated by great distances and times. Although the economic value to humans contributed by most, if not all, of the supporting services has yet to be quantified, we believe they are important to humans. Our goals for this review are 1) to lay the groundwork on these services to facilitate future efforts to estimate their economic value, 2) to highlight gaps in our knowledge, and 3) to point to future directions for additional research.

Ecosystem Services Provided by Birds

Summary 1. Agricultural intensification is perceived to be a major cause of the decline in many European bat populations. Because organic farming prohibits the use of agrochemicals, we compared organic vs. conventional farm types to test the hypothesis that agricultural intensification based on high levels of agrochemical use has been a factor in bat population declines. Bat activity and species richness were compared on matched pairs of organic and conventional farms. 2. Bat activity was quantified using acoustic surveys within specific habitats on farms in southern England and Wales. Eighty-nine per cent of bat passes were identified to species level using artificial neural networks (ANN). A further 9% were identified to genus. 3. Total bat activity was significantly higher on organic farms than on conventional farms. Significantly more bat passes were recorded over water on organic farms than on conventional farms. Foraging activity (quantified in two ways: total feedings buzzes and feeding buzzes per pass) was significantly higher on organic farms than on conventional farms. 4. The dominant species on both farm types were Pipistrellus pipistrellus and Pipistrellus pygmaeus . Significantly more passes of Myotis species were recorded on organic farms than on conventional farms. This difference was also significant when water habitats were considered alone. 5. The activity of both Myotis daubentonii and Myotis brandtii was significantly higher on organic farms than on conventional farms. The activity of Myotis bechsteinii and Myotis brandtii was significantly higher over organic water habitats than over conventional water habitats. Rhinolophus hipposideros and Rhinolophus ferrumequinum were only recorded on organic farms in wooded, arable and pasture habitats. 6. Synthesis and applications. This study highlights the position of bats as bioindicators and victims of agricultural change. The differences in bat activity between farm types may reflect features such as taller hedgerows and better water quality on organic farms. Higher foraging activity also suggests that habitat quality in terms of prey availability is greater on organic farms. Less intensive farming benefits bats, and as the number of organic enterprises increases it may help to reverse declines in bat populations.

https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2664.2003.00856.x

Bat activity and species richness on organic and conventional farms: impact of agricultural intensification.

: Insects are the principal food for many animals, including bats (Chiroptera), and all species of bats in the United Kingdom feed over agricultural habitats. Bat populations are declining throughout Europe, probably in part as a result of agricultural intensification. Organic farming prohibits the use of agrochemicals, a major component of agricultural intensification, making it an ideal control for a study of intensive agricultural systems. To evaluate the impact of agricultural intensification on bat foraging, we quantified the availability of bat prey by comparing nocturnal aerial insects captured within habitats on 24 matched pairs of organic and conventional farms. Insects were identified to family and moths to species. We compared the abundance of 18 insect families commonly eaten by bats in the United Kingdom between farm types and tested for correlations of abundance with bat activity. Insect abundance, species richness, and moth species diversity were significantly higher on organic farms than on conventional farms. Insect abundance was significantly higher in pastural and water habitats on organic farms than in the same habitats on conventional farms. Of the 18 insect families that are important components of the bat diet, 5 were significantly more abundant on organic farms overall. Some were also more abundant within organic pastural, woodland, and water habitats than on conventional farmland habitats. The activity of bats that mainly ate Lepidoptera was significantly correlated with the abundance of this order. Our observations suggest that agricultural intensification has a profound impact on nocturnal insect communities. Because bats are resource limited, a reduction in prey availability through agricultural intensification will adversely affect bat populations. Less-intensive farming benefits British bat populations by providing and maintaining diverse and structurally varied habitats, which in turn support a wide selection of insect prey for bats, including insect families that are significant components of the diet of a number of rare bat species.




Resumen: Los insectos son el alimento principal de muchos animales, incluyendo murcielagos (Chiroptera), y todas las especies de murcielagos en el Reino Unido se alimentan en habitats agricolas. Las poblaciones de murcielagos estan declinando en toda Europa, en parte probablemente debido a la intensificacion agricola. La agricultura organica prohibe el uso de agroquimicos, un componente mayor de la intensificacion agricola, haciendolos un control ideal para un estudio de sistemas agricolas intensivos. Para evaluar el impacto de la intensificacion agricola sobre el forrajeo de murcielagos, cuantificamos la disponibilidad de sus presas mediante la comparacion de insectos aereos nocturnos capturados en habitats en 24 pares similares de granjas organicas y convencionales. Los insectos fueron identificados hasta familia y las polillas hasta especie. Comparamos la abundancia de 18 familias de insectos comidos comunmente por murcielagos en el Reino Unido en los dos tipos de granja y probamos correlaciones de su abundancia con la actividad de murcielagos. La abundancia, riqueza de especies de insectos y la diversidad de especies de polillas fueron significativamente mayores en las granjas organicas que en las convencionales. La abundancia de insectos en las granjas organicas fue significativamente mayor en habitats de pastoreo y con agua que en los mismos habitats en granjas convencionales. De las 18 familias de insectos que son componentes importantes de la dieta de murcielagos, cinco fueron significativamente mas abundantes en las granjas organicas. Algunas tambien fueron mas abundantes en habitats de pastoreo, arbolados y con agua en granjas organicas que en habitats de granjas convencionales. La actividad de murcielagos que se alimentaron principalmente de Lepidopteros estuvo correlacionada significativamente con la abundancia de este orden. Nuestras observaciones sugieren que la intensificacion agricola tiene un profundo impacto sobre la comunidad de insectos nocturnos. Debido a que estan limitadas por recursos, una reduccion en la disponibilidad de presas por la intensificacion agricola afectara a las poblaciones de murcielagos adversamente. La agricultura menos intensiva beneficia a las poblaciones Britanicas de murcielagos al proporcionar y mantener habitats diversos y estructuralmente variados, que a su vez soportan a una amplia seleccion de insectos presa para murcielagos, incluyendo familias de insectos que son componentes significativos de la dieta de especies de murcielagos raras.

Liat P. Wickramasinghe

Papers

Bat activity and species richness on organic and conventional farms: impact of agricultural intensification.

Abundance and Species Richness of Nocturnal Insects on Organic and Conventional Farms: Effects of Agricultural Intensification on Bat Foraging

Designing bat activity surveys using time expansion and direct sampling of ultrasound