Monitoring the influx of new species through citizen science: the first introduced ant in Denmark

Abstract

Climate change and invasive species threaten biodiversity, yet rigorous monitoring of their impact can be costly. Citizen science is increasingly used as a tool for monitoring exotic species, because citizens are geographically and temporally dispersed, whereas scientists tend to cluster in museums and at universities. Here we report on the establishment of the first exotic ant taxon (Tetramorium immigrans) in Denmark, which was discovered by children participating in The Ant Hunt. The Ant Hunt is a citizen science project for children that we ran in 2017 and 2018, with a pilot study in 2015. T. immigrans was discovered in the Botanical Garden of the Natural History Museum of Denmark in 2015 and confirmed as established in 2018. This finding extends the northern range boundary of T. immigrans by almost 460 km. Using climatic niche modelling, we compared the climatic niche of T. immigrans in Europe with that of T. caespitum based on confirmed observations from 2006 to 2019. T. immigrans and T. caespitum had a 13% niche overlap, with T. immigrans showing stronger occurrence in warmer and drier areas compared to T. caespitum. Mapping the environmental niches onto geographic space identified several, currently uninhabited, areas as climatically suitable for the establishment of T. immigrans. Tetramorium immigrans was sampled almost three times as often in areas with artificial surfaces compared to T. caespitum, suggesting that T. immigrans may not be native to all of Europe and is being accidentally introduced by humans. Overall, citizen scientists collected data on ants closer to cities and harbours than scientists did and had a stronger bias towards areas of human disturbance. This increased sampling effort in areas of likely introduction of exotic species naturally increases the likelihood of discovering species sooner, making citizen science an excellent tool for exotic species monitoring, as long as trained scientists are involved in the identification process.

Effect of social structure and introduction history on genetic diversity and differentiation

“…The occurrence of some geographical differentiation is also supported by a pattern of IBD and a rough west/east clustering in structure (Figures 5a and 7a). The recently detected occurrence in Denmark (Sheard et al, 2020; Table S2) might account for a current expansion from Western Europe to more northern locations in Europe (Figure 1) but could be limited to urbanized habitats with warmer environmental conditions (Gippet et al, 2017). Since T. tsushimae spreads at least partly…”

“…In addition to the main data set, fully overlapping mtDNA sequences of 169 individuals of T. immigrans (Schlick-Steiner et al, 2006;Wagner et al, 2017) and 23 individuals of T. tsushimae (Steiner et al, 2006) were downloaded from GenBank (see Table S3 for GenBank accession numbers) and three recently discovered occurrences of T. immigrans in Denmark (Sheard et al, 2020) were sequenced. The haplotypes of the three samples were identified using 0.2 µm 1718f and PAT primers (Simon et al, 1994), 1× OneTaq reaction buffer and 0.125 U OneTaq polymerase (New England Biolabs) in 10-µl reaction volumes.…”

From Phenology and Habitat Preferences to Climate Change: Importance of Citizen Science in Studying Insect Ecology in the Continental Scale with American Red Flat Bark Beetle, Cucujus clavipes, as a Model Species

“…In the literature, there are numerous examples where observations by citizen scientists allow to assess, monitor, and predict biodiversity on local, regional, country, continental, or global scale, e.g., [ 3 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. In many cases citizen scientists helped, e.g., to delimit the geographical distribution of a species, e.g., [ 15 , 16 ]; to find species for the first time in the country, e.g., [ 17 , 18 , 19 , 20 ], in the continent, e.g., [ 21 , 22 , 23 ]; or even to discover new taxa, e.g., [ 21 , 24 , 25 , 26 , 27 , 28 , 29 ]. Moreover, such observations allow to monitor migratory birds, e.g., [ 30 , 31 , 32 , 33 , 34 ]; rare and endangered species, e.g., [ 35 , 36 , 37 , 38 ]; expansion of pests, e.g., [ 20 , 39 , 40 ]; or alien and/or invasive species, e.g., [ 18 , 22 , 39 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ,…”

“…In many cases citizen scientists helped, e.g., to delimit the geographical distribution of a species, e.g., [ 15 , 16 ]; to find species for the first time in the country, e.g., [ 17 , 18 , 19 , 20 ], in the continent, e.g., [ 21 , 22 , 23 ]; or even to discover new taxa, e.g., [ 21 , 24 , 25 , 26 , 27 , 28 , 29 ]. Moreover, such observations allow to monitor migratory birds, e.g., [ 30 , 31 , 32 , 33 , 34 ]; rare and endangered species, e.g., [ 35 , 36 , 37 , 38 ]; expansion of pests, e.g., [ 20 , 39 , 40 ]; or alien and/or invasive species, e.g., [ 18 , 22 , 39 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ] as well as colonization of new human-made habitats, e.g., [ 51 ]. In addition, numerous studies show that data collected by amateur scientists allow to describe new interactions between species, e.g., [ 17 , 52 ], to investigate animal phenology, e.g., [ 53 ], and behavior, e.g., [ 54 ], to find changes in species abundance and demography, e.g., [ 55 <...>…”

Public Engagement Provides First Insights on Po Plain Ant Communities and Reveals the Ubiquity of the Cryptic Species Tetramorium immigrans (Hymenoptera, Formicidae)

“…First launched in the United States [ 45 , 46 ] and then spread to other countries [ 47 , 48 , 49 ], the citizen science project “School of Ants” (SoA) aims to fill this knowledge gap, studying urban ant biodiversity through large public involvement. In Italy, the project, led by the Myrmecology Lab (University of Parma—UNIPR), has further developed around the need of counteracting the scarcity of practical scientific experiences within Italian schools and it has now flown into the project “School of Ants: a scuola con le formiche” (SoA: learning with the ants).…”