Landscape change and alien invasions drive shifts in native lady beetle communities over a century

Abstract

AimUnderstanding drivers of insect population declines is essential for the development of successful conservation plans, but data limitations restrict assessment across spatial and temporal scales. Museum records represent a unique source of historical data that can be leveraged to investigate temporal trends in insect communities. Native lady beetle decline has been attributed to competition with established alien species and landscape change, but the relative importance of these drivers is difficult to measure with short-term field-based studies. Here we assessed distribution patterns for native lady beetle species over 12 decades using museum records and evaluated the relative importance of alien species and landscape change as long-term drivers contributing to changes in lady beetle communities.LocationOhio, USA.MethodsWe compiled occurrence records for 28 lady beetle species collected in Ohio, USA from 1900-2018. Incidence-based measures of taxonomic beta-diversity were used to evaluate changes in lady beetle community composition over time. To evaluate the relative influence of temporal, spatial, landscape, and community drivers on the captures of native lady beetles, we constructed negative binomial generalized additive models.ResultsWe report evidence of declines in captures for several native species, including Adalia bipunctata, Coccinella novemnotata, Hippodamia convergens, and Coleomegilla maculata. Importantly, the timing, severity, and drivers of these documented declines were species-specific. Changes in lady beetle species composition began in the 1980s, when processes of species loss/gain and turnover shifted communities towards dominance by a few alien lady beetle species. Land cover change also was associated with declines in captures, particularly for C. novemnotata which declined prior to the arrival of alien species in the state.Main conclusionsOur study documented shifts in Ohio’s lady beetle communities beginning in the 1980s as alien species supplanted natives. Drivers of declines in captures of native lady beetle species were highly species-specific, emphasizing that mechanisms driving population losses cannot be generalized even among closely related species. These findings also indicate the importance of museum holdings and the analysis of species-level data when studying temporal trends in insect populations.

Landscape simplification, urbanization, biological invasions, and climate change: a review of the major threats to native coccinellids in Central Chile

“…Several studies have shown that the composition, abundance, diversity, and even body condition of coccinellids in crops are affected by the composition and configuration of the surrounding landscapes (e.g., Caballero‐López et al., 2012; Woltz & Landis, 2014; Janković et al., 2017; Tiede et al., 2022); this may occur because some functional habitats, especially for native coccinellids, are disappearing, resulting in a loss of hibernation sites or habitats with alternative resources (Soares et al., 2022). Furthermore, landscape simplification, the disappearance of natural habitats, and the increase of highly disturbed crops may result in an increase in the dominance of exotic invasive species (Grez et al., 2013; Perry et al., 2022), which may also negatively affect native coccinellid abundance and diversity.…”

“…Coccinellids (Coleoptera) are an important group of insects, with more than 6000 species widely distributed around the globe, contributing to provisioning (e.g., medicinal), regulation and maintenance (e.g., biological control), and cultural (e.g., educational) services (Hodek et al., 2012; for details see Appendix S2 in Soares et al., 2022). Nevertheless, coccinellid populations are declining, particularly of native species (Brown & Roy, 2018; Hesler & Beckendorf, 2021; Perry et al., 2022). Three main threats worldwide are responsible for this decline: biological invasions; agricultural intensification, landscape simplification, and urbanization; and climate change (Honek et al., 2017; Soares et al., 2022).…”