Abstract Detail

Ecology

Hatajik, Jack [1], Lee, Ben [2], Heberling, Mason [3].

Mapping the population dynamics of the invasive Alliaria petiolata (garlic mustard) in response to climate.

Invasive species (defined as organisms that cause ecological or economic harm in a new environment where they are not native) are identified in the Intergovernmental Panel on Climate Change’s latest Special Report as one of the greatest threats to native biodiversity and nutrient cycles around the world. Importantly, approximately 42% of threatened or endangered species around the world are currently at risk due to invasive species through mechanisms such as competition for resources and allelopathy. Alliaria petiolata (garlic mustard) is considered highly invasive in eastern North America after being introduced from Eurasia in the mid-1800s and is now one of the most aggressive invaders on the continent having been documented in 40 U.S. states and 5 Canadian provinces. This species is problematic because it is allelopathic and disrupts mycorrhizal mutualisms of native plant species, thereby reducing performance and potentially compromising persistence in native ecosystems. As such, a great deal of effort has been put into the removal of this weedy invader through chemical, mechanical, and/or integrated controls. Because of its importance in the management and conservation of natural ecosystems, it is integral that we understand the drivers of its invasion and the factors that allow it to persist across the landscape. For example, past research has identified extreme climate events (such as severely hot and dry summers) as limiting the distribution of Alliaria in the eastern US. Other research has identified conspecific negative density dependence (CNDD), where a high abundance of Alliaria leads to higher intraspecific competition compared to competition with other species, as a major limitation. Some authors even suggest that CNDD causes Alliaria to gradually reduce in allelopathy over time, leading to reduced population size and reduced persistence in areas where Alliaria invaded relatively early. Although support exists for both theories, a gap in the literature exists comparing them against each other. I performed a combined herbarium, field, and laboratory study in which I have 1) mapped the invasion of Alliaria using historical museum specimens, 2) used this information to estimate time since invasion at sites across the eastern U.S., 3) measured Alliaria abundance, allelopathy, and population-level metrics across a range of these sites, and 4) evaluated whether environmental conditions or reductions in CNDD provide a better explanation for observed patterns of Alliaria distributions. Results from this will inform land managers and conservationists about the population dynamics of this pervasive weedy invader and broaden our understanding of the population dynamics of invasive species in general. Although this research is limited to Alliaria, it will provide a resource these professionals can use to inform management practices and improve cost efficiency.

1 - 15 Melba Place, Apartment 2, Pittsburgh, PA, 15213, United States
2 - 38 Exeter St., Pittsburgh, PA, 15217, United States
3 - Carnegie Museum Of Natural, Section Of Botany, 4400 Forbes Ave, Pittsburgh, PA, 15213, United States

Keywords:
Alliaria petiolata
Herbarium
climate change
time since invasion
population decline
invasive species.

Presentation Type: Poster
Number: PEC005
Abstract ID:84
Candidate for Awards:None