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No abstract

Conservation strategies centered around species habitat protection rely on species’ dietary information. One species at the focal point of conservation efforts is the herbivorous grouse, the western capercaillie (Tetrao urogallus), which is an indicator species for forest biodiversity conservation. Non‐molecular means used to study their diet are time‐consuming and at low taxonomic resolution. This delays the implementation of conservation strategies including resource protection due to uncertainty about its diet. Thus, limited knowledge on diet is hampering conservation efforts. Here, we use non‐invasive environmental DNA (eDNA) metabarcoding on DNA extracted from faces to present the first large‐scale molecular dietary analysis of capercaillies. Facal samples were collected from seven populations located in Norway (Finnmark, Troms, Trøndelag, Innlandet) and France (Vosges, Jura, Pyrenees) (n = 172). We detected 122 plant taxa belonging to 46 plant families of which 37.7% of the detected taxa could be identified at species level. The average dietary richness of each sample was 7 ± 5 SD taxa. The most frequently occurring plant groups with the highest relative read abundance (RRA) were trees and dwarf shrubs, in particular, Pinus and Vaccinium myrtillus, respectively. There was a difference in dietary composition (RRA) between samples collected from the different locations (adonis pseudo F5,86 = 11.01, r2 = 0.17, p = 0.001) and seasons (adonis pseudo F2,03 = 0.64, r2 = 0.01, p = 0.036). Dietary composition also differed between sexes at each location (adonis pseudo F1,47 = 2.77, r2 = 0.04, p = 0.024), although not significant for all data combined. In total, 35 taxa (36.8% of taxa recorded) were new capercaillie food items compared with existing knowledge from non‐molecular means. The non‐invasive molecular dietary analysis applied in this study provides new ecological information of capercaillies’ diet, improving our understanding of adequate habitat required for their conservation.

Arthropods are essential in maintaining healthy and productive agricultural ecosystems. Agricultural crops such as apples are typically pollinated by domesticated honey bees, but wild bees and other arthropod flower visitors also contribute to pollination. Flower visitors can also be natural enemies of crop‐pests or herbivores. Biodiversity is under pressure and knowledge of wildflower visitors is an important tool in designing orchards that can support high functional biodiversity. In our study, we assessed the diversity of arthropod flower visitors in four Danish apple orchards using both molecular and nonmolecular techniques to study arthropod communities in agricultural ecosystems. Arthropod DNA collected from apple flowers was analyzed using a DNA metabarcoding approach using the mitochondrial COI marker, while arthropod pollinators were recorded through visual assessment surveys. These complementary techniques resulted in a total of 19 arthropod taxa detected. Nonbee arthropods constituted a large proportion of arthropods detected by both methods (84%, 16 taxa). Metabarcoding detected 12 taxa and had 83% species resolution. Visual census recovered flower visiting groups to the order level (Coleoptera, Diptera, Hymenoptera and Lepidoptera) but not species level and also provided relative abundance data, which is not possible with molecular methods. We demonstrated that by utilizing both molecular and nonmolecular techniques to assess arthropod communities, we are able to obtain a broader overview of the arthropod fauna present. The methodology used and the outcome of this study can be used to inform and tailor suitable arthropod‐pest management practices in orchards to increase crop yield and maintain healthy agricultural systems.