Potential spatial interaction of the invasive species Harmonia axyridis (Pallas) with native and endemic coccinellids

Abstract

Biological invasions represent a serious menace to local species assemblages, mainly due to interspecific relationships such as competition and predation. One important invasive species worldwide is Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), which has invaded many regions of the world, threatening the native and endemic coccinellid assemblages due to negative interspecific interactions. These interactions have been widely studied at a local scale, but have been less studied at regional scales. Our aim was to estimate and analyse the potential spatial interaction associated with the co‐occurrence of H. axyridis with native and endemic species in Chile, considering bioclimatic and land cover variables. First, we created species distribution models (SDM) for H. axyridis, native and endemic coccinellids and six representative coccinellid species using maximum entropy technique. Then, we overlapped each SDM with land cover types to estimate the bioclimatic suitability within each land cover type. Finally, we identified the co‐occurrences of organisms according to the SDM and the land cover types, estimating in what land covers H. axyridis and the other coccinellids are more likely to co‐occur. Our results show that the suitable area for H. axyridis occurs from 30° to 42°S in Chile, while for native and endemic species this area is greater. The six selected species are mainly concentrated in central Chile, but differ in their potential suitable areas; Adalia angulifera Mulsant and Scymnus bicolor (Germain) have the largest range, and Mimoscymnus macula (Germain) has the most restricted one. The highest level of potential spatial interactions with H. axyridis occurs in central Chile, specifically in croplands and scrublands, and the lowest in primary native forest for all the species. Our results provide a spatially explicit baseline for coccinellid conservation and management of this invasive species.

Citizen science reveals the distribution of the invasive harlequin ladybird (Harmonia axyridis Pallas) in Argentina

“…Our study expands the range of H. axyridis * 600 km further north than in Chile where the species seems to be restricted due to the presence of the Atacama Desert (Alaniz et al 2018;Grez et al 2016). Nevertheless, our records in the north correspond to a small region of subtropical forests in the East (Paraná Forest and Araucaria Forest) and West (Yungas) of Argentina, confirming the habitat matching predictions for this biome (Koch et al 2006).…”

“…The southern limit is mismatched with climatic predictions (Koch et al 2006;Poutsma et al 2007), but is climatically similar to some regions from which reports were generated in Chile (Alaniz et al 2018;Grez et al 2016) and to high latitudes in the United Kingdom, where the species shows limited abundance in northern England and Scotland (Purse et al 2015;Roy et al 2016). This high latitude limit in the invaded region has been related to the combination of low temperatures and high precipitation (Alaniz et al 2018;Roy et al 2016) and to the low density of urban areas (Purse et al 2015). In our study, most of the southern records were reported in the Valdivian Forest, close to the Andes, where precipitation is high ([ 2000 mm/year) compared to the east of the country (ca.…”

Current and future spatial assessment of biological control as a mechanism to reduce economic losses and carbon emissions: the case of Solanum sisymbriifolium in Africa

“…Suitability values under the tenth percentile were excluded from the analysis and classified as null (null = 0). These new reclassified rasters were multiplied by a double‐entry matrix, based on the methodology of Alaniz et al . The result of the raster multiplication represents the probability of interaction between two species, ranging from null to very high; interpreted as a proxy of the expected strength of the biological control service (Table ).…”

“…First, we subtracted the non‐significant suitability values considering the tenth percentile of training presence as the threshold, and then reclassified the significant suitability values into three levels (low = 1, medium = 2, high = 3). We used a double‐entry matrix to multiply the rasters of G. spadicea by S. sisymbriifolium in each RCP scenario, obtaining as a product two maps of PSI, one per RCP scenario, with five levels of PSI (very low to very high) . We then considered as effective biocontrol PSI levels above the medium, overlapping this with the cropland layer from ESA CCI GlobCover 2015.…”

Global spatial assessment of Aedes aegypti and Culex quinquefasciatus: a scenario of Zika virus exposure

“…This could be considered a more parsimonious way to determine each one of the levels because the thresholds which divide each one of the levels are scaled in relation to the probability range of each SDM. These new discrete grids of suitability were multiplied, obtaining a grid with levels of potential spatial interaction from null to very high, associated with the spatial co-occurrence of both mosquitoes [ 37 ]. These areas were named ‘Interaction zones’ (Supplementary data, Fig.…”