Leaf Herbivory of Native and Non-Native Oaks in the Upstate of South Carolina
Abstract
Native plants typically experience higher levels of insect herbivory compared to non-native plants, often due to a lack of shared evolutionary history and adaptation. Caterpillars are the main cause of leaf herbivory and have impactful roles on local ecosystems. Higher caterpillar counts in an ecosystem typically correlates to a higher songbird abundance and greater biodiversity within food webs. This is particularly notable in the United States, where native oaks (Quercus spp.) host a greater variety of caterpillar species compared to other tree types. Despite this, several non-native oaks, such as the sawtooth oak (Quercus acutissima), were introduced from East Asia in the 1860s and have been planted across the United States. Sawtooth oaks were introduced for their ornamental value and gained popularity among land managers. Sawtooth oaks have also been of interest to game managers as they produce a lot of acorns that are then consumed by white-tailed deer (Odocoileus virginianus) and wild turkeys (Meleagris gallopavo). However, the sawtooth oak has since been identified as invasive in eight eastern states. This study aimed to assess whether non-native sawtooth oaks exhibit lower levels of caterpillar herbivory compared to two widespread native oaks: the white oak (Quercus alba) and southern red oak (Quercus falcata). These two species are commonly found together in nature. Leaf samples were collected from 20 individuals of each oak species, and leaf herbivory levels were quantified using the Leafbyte app. Data were analyzed using a nested ANOVA. Our prior work in 2022 showed that southern red oaks experienced significantly higher leaf herbivory compared to non-native sawtooth oaks, while no significant difference was observed between sawtooth oaks and white oaks. We will present herbivory data for 2023 and make comparisons between these oaks in a second field season. We will also compare the levels of herbivory between 2022 and 2023.
Keywords
herbivory, oak species, invasive species, habitat management, biodiversity, caterpillar
Leaf Herbivory of Native and Non-Native Oaks in the Upstate of South Carolina
CLC Ballroom
Native plants typically experience higher levels of insect herbivory compared to non-native plants, often due to a lack of shared evolutionary history and adaptation. Caterpillars are the main cause of leaf herbivory and have impactful roles on local ecosystems. Higher caterpillar counts in an ecosystem typically correlates to a higher songbird abundance and greater biodiversity within food webs. This is particularly notable in the United States, where native oaks (Quercus spp.) host a greater variety of caterpillar species compared to other tree types. Despite this, several non-native oaks, such as the sawtooth oak (Quercus acutissima), were introduced from East Asia in the 1860s and have been planted across the United States. Sawtooth oaks were introduced for their ornamental value and gained popularity among land managers. Sawtooth oaks have also been of interest to game managers as they produce a lot of acorns that are then consumed by white-tailed deer (Odocoileus virginianus) and wild turkeys (Meleagris gallopavo). However, the sawtooth oak has since been identified as invasive in eight eastern states. This study aimed to assess whether non-native sawtooth oaks exhibit lower levels of caterpillar herbivory compared to two widespread native oaks: the white oak (Quercus alba) and southern red oak (Quercus falcata). These two species are commonly found together in nature. Leaf samples were collected from 20 individuals of each oak species, and leaf herbivory levels were quantified using the Leafbyte app. Data were analyzed using a nested ANOVA. Our prior work in 2022 showed that southern red oaks experienced significantly higher leaf herbivory compared to non-native sawtooth oaks, while no significant difference was observed between sawtooth oaks and white oaks. We will present herbivory data for 2023 and make comparisons between these oaks in a second field season. We will also compare the levels of herbivory between 2022 and 2023.