Landscapes and Invasion


Invasive plants and conservation linkages

Linkage in San Diego
A conceptual model and baseline

My PhD dissertation revolves around the largely unaddressed topic of invasive plants within conservation linkages. Linkages (or corridors) are strips of land that are meant to connect the landscape, enabling native animals and plants to move and thus diminish negative effects of habitat isolation and fragmentation. However, unwanted species may also utilize these linkages, potentially lessening their effectiveness in helping native species. To aid researchers and land managers, I developed a conceptual model that outlines broad ways in which invasive plants may interact with conservation linkages. I highlighted the importance of considering invasive plant dispersal ecology and the role of the matrix types (habitats surrounding the conserved linkage land). I used several key research questions as guides for researchers and managers in determining how to study, understand, and manage their linkages with respect to invasive plants. This conceptual model fits another piece into the puzzle of landscape connectivity via linkages.

Published paper

Conservation Corridor blurb

 

Hedgerow (and quadrat) in Yolo County

Hedgerows in Northern Central Valley, California

I used hedgerows in contiguous counties in northern Central Valley as pseudo-linkages to examine some of the concepts in the conceptual model described above. I collected observational data on all invasive plant species frequencies and abundances in thirty some odd hedgerows. I used multivariate analysis techniques to determine what landscape variables may be correlated with the spatially-explicit patterns of invasive plants, overall and within dispersal groups. The results of my research will be used to help conservation practitioners and private landowners better understand and potentially control invasive plants in their hedgerow plantings.
Published paper

 

 

 

Linkage edge in W. Riverside County

 

 

Southern California Landscape Linkages
In Southern California, I identified several large-scale (multi-kilometer long) conservation linkages in Riverside and San Diego County that are mostly conserved under the auspices of County Habitat Conservation Plans (HCPs). Using many of the same methods as above, I collected data on a suite of focal invasive plants of concern to local land managers. In this project, I focused more on how different matrix types (e.g., orchard vs. suburban housing vs. low-density housing) impact invasive plant patterns in linkage edges and how those patterns change or do not change moving into the interior of the linkage. Again, my research is intended to help guide land managers in understanding how linkage structure and placement may interact with invasive plant patterns. My results will also help determine how to prioritize invasive control efforts depending on linkage, matrix, and species characteristics. [highlight color=”gray”] Manuscript in prep [/highlight]

 

 

 

 

Field sites at Harvard Forest
Garlic mustard in New England

As part of my NSF-funded internship in undergraduate, I was part of an ongoing research project on the invasive garlic mustard, Alliaria petiolata, at the research station Harvard Forest in central Massachusetts. With my work-partner, Jens Stevens, and under the guidance of our PI, Dr. Kristina Stinson, we collected data on a reciprocal transplant study and also started an observational examination of population demographics of invasive spread in certain Massachusetts ecoregions. We found that maternal effects did have impacts on the success of garlic mustard individuals and that plants that came from sun-reared maternal plants did better in sun, mid-shade, and deeper shade (forest understory). In our observational study, we found that the largest populations of garlic mustard were still in the ditches and the edges of forests. The few understory populations were very young and small. At that time and in that place, garlic mustard was still a sun-adapted invasive species.