Examining the effects of plant diversity on insect biodiversity in natural and semi-natural grasslands

The number of intact native (natural or semi-natural) grasslands in Saskatchewan has been greatly reduced over recent decades; agricultural land development and invasion from exotic plant species are considered to be important drivers for this reduction. An important consequence of agricultural land development and plant invasion is the simplification of plant species diversity in affected ecosystems. This simplification can increase the spread of pathogens, alter existing ecological interactions, and lead to simplification of communities at higher trophic levels such as primary consumers. Additionally, research suggests that lower plant diversity can impact the types and quality of ecosystem services of terrestrial ecosystems. Terrestrial arthropods are the greatest contributors to terrestrial animal biomass and provide valuable ecosystem services such as decomposition, herbivory, pollination, and population control of other arthropod species. Most terrestrial arthropods rely on plant species at some point in their life cycle, with many arthropod species forming being heavily reliant on species plant families or species as sources for food or oviposition sites. This reliance on plant species means that insect diversity can be linked to plant diversity; higher plant species diversity should result in more insect species being recruited to the ecosystem. To examine this relationship in a natural setting both passive and active sampling was conducted across three summer months and a plant census was done to determine local plant diversity and light penetration. We used eDNA from the passive samples in conjunction with morphological identification to determine the insect community makeup.