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Research

My field of specialization is conservation biology. My field research is focused on species interactions and subsequent impacts on ecosystem processes, especially focused on the issues of invasive species and climate change.

Climate change research, Alaska:

person in fieldaerial image of Yukon DeltaWorking with colleagues at the University of Alaska Anchorage, USGS Alaska Science Center, University of Nevada, and Colorado State University, I have an NSF-funded project to study how climate change affects goose arrival time and the start of the growing season in the Yukon-Kuskokwim Delta.  Geese that breed and molt in Arctic ecosystems are extremely selective for high quality (high nitrogen and low digestibility) forage.  We are conducting a highly manipulative experiment where we are altering the timing of goose arrival (foraging) and the start of the growing season to investigate how these factors influence C and N cycling, the quality of forage quality and whether geese mediate the effects of climate change by altering soil and plant nutrition, vegetation canopy traits, and plant demography.  I have one PhD student and one MS student conducting research in this system.

Invasive research, animals:

People wearing headlamps inspecting something in their hands at nightcloseup of frogMy research on invasive animals began when I was conducting my dissertation research at the Luquillo LTER in Puerto Rico, where I explored how the extinction of a native frog, Eleutherodactylus coqui (hereafter the coqui), could impact its community and ecosystem. During that research, the coqui was identified as a serious invader in Hawaii. While at Utah State University, I have used my knowledge of the coqui in its native range to understand its invasion and impacts on biological diversity and habitats in Hawaii. My work provided one of the first examples in the literature of the mechanisms through which a terrestrial vertebrate predator affects nutrient cycling (Sin et al. 2008 Biological Invasions; Beard et al. 2002 Oecologia). My research on this topic has lead me to explore the genetic and evolutionary consequences of the invasion, the impact of the invader on prey and predators, the relative importance of this introduction and other introductions, and the interactions between this invader and other invaders. We are currently investigating whether coquis compete with birds and the predators of coquis of Hawaii.  I am also interested, more generally in patterns of amphibian and reptile invasions. Three PhD students and six MS students have conducted research in the study system. 

Invasive research, plant:

people working in a fieldfieldThis research focuses on studying non-native plant growth in the Intermountain West. In this research, we have investigated the relative importance of various factors to explain plant community assembly, emphasizing plant-soil feedbacks but also investigating such factors as water-use patterns and ungulate herbivory. Our approach has been at the forefront of ecological research because it uses multiple hypothesis testing (Kulmatiski et al. 2006 Journal of Ecology) and also because it presents a novel explanation for plant community dynamics (Kulmatiski et al. 2012 Proceedings of the Royal Society). We have also been investigating the importance of techniques to restore native and forage species to invaded communities, such as activated carbon. Four of my MS students have conducted theses related to this research.

Climate change research, South Africa and Utah:

fieldpeople in fieldI have been working on community and ecosystem-level responses to climate change for 10 years. I worked in the Luquillo LTER in Puerto Rico on the effects of hurricanes and droughts on forest ecosystem function and process, resulting in an Ecological Monograph (2005). Since 2007, I started investigating how climate change predictions of altered precipitation will influence tree and grass interactions in Kruger National Park, South Africa through Mellon Foundation grants. Thus far, I have published research on this topic in Oecologia (2012), New Phytologist (2010) and Nature Climate Change (2013). This research has been field-oriented focusing on experimental manipulation, such as rainout shelters, and pulse-chase tracer techniques.  I am starting a new precipitation-manipulation experiment in Utah in 2015.

Other interests:

people in jungleI am interested in the effects of habitat fragmentation and loss on species diversity.  I was senior author on a review of the effectiveness of habitat corridors in facilitating species movements, which was published in Conservation Biology in 2010 and won an international award (IALE- Outstanding Paper in Landscape Ecology). I also co-authored a manuscript on habitat fragmentation in south California's coast sage scrub ecosystem published in Diversity and Distributions. I had a PhD student working on the effects of habitat fragmentation on bromeliad-dependent frogs in Brazil and another PhD student working on the social aspects of the invasion of a noisy frog in Hawaii. I currentlyl have a PhD student interested in soundscapes in the Amazon.  I am inspired by graduate students and encourage them to explore many different areas of research.