Humans are changing the natural world at breakneck pace, and novel plant-animal interactions are becoming increasingly common. Plant-animal interactions can also influence the effect of ecological restoration, where humans try to promote biodiversity. My research program studies interactions between plants and animals in novel habitats, with three broad research questions:
1) How do novel and restored habitats change animal behavior?
2) What are the effects of climate change on species interactions during winter?
3) What are the effects of invasive species on species interaction during autumn?
1) How do novel and restored habitats change animal behavior?
2) What are the effects of climate change on species interactions during winter?
3) What are the effects of invasive species on species interaction during autumn?
Species interactions in novel and restored ecosystems
Anthropogenic climate change has reversed a 60 million-year cooling trend, creating “novel” climates with no recent analog. However, climatic novelty is just one dimension of ecological novelty that interacts with other dimensions (e.g., habitat loss, invasive species) in complex ways. As a member of an interdisciplinary working group sponsored by the National Science Foundation, I worked with other ecologists, economists, historians, and journalists to understand the causes and consequences of ecological novelty. I led a collaboration that proposed a new framework to organize and predict the complex interactions between climate change and other drivers of ecological novelty on predator-prey interactions (Guiden et al. 2019, Trends in Ecol. & Evol.), which will help develop new experiments that fill key knowledge gaps and make more mechanistic predictions of species responses to climate change.
While novel ecosystems often threaten biodiversity, ecologists can offer hope by helping to restore plant communities. As a post-doctoral fellow, I am collaborating with The Nature Conservancy to evaluate the ecosystem-wide consequences of bison reintroduction and prescribed fire at Nachusa Grasslands (Franklin Grove, IL). We have found that restoring plant diversity does not necessarily restore animal diversity, but rather animals respond independently to fire and grazing (Guiden et al., in revision at PNAS. Future research will examine the potential for bison grazing to alter the behavior of seed predators: pilot data suggest that small mammals are more sensitive to predation risk in bison-grazed habitats, and consequently may consume fewer seeds.
Anthropogenic climate change has reversed a 60 million-year cooling trend, creating “novel” climates with no recent analog. However, climatic novelty is just one dimension of ecological novelty that interacts with other dimensions (e.g., habitat loss, invasive species) in complex ways. As a member of an interdisciplinary working group sponsored by the National Science Foundation, I worked with other ecologists, economists, historians, and journalists to understand the causes and consequences of ecological novelty. I led a collaboration that proposed a new framework to organize and predict the complex interactions between climate change and other drivers of ecological novelty on predator-prey interactions (Guiden et al. 2019, Trends in Ecol. & Evol.), which will help develop new experiments that fill key knowledge gaps and make more mechanistic predictions of species responses to climate change.
While novel ecosystems often threaten biodiversity, ecologists can offer hope by helping to restore plant communities. As a post-doctoral fellow, I am collaborating with The Nature Conservancy to evaluate the ecosystem-wide consequences of bison reintroduction and prescribed fire at Nachusa Grasslands (Franklin Grove, IL). We have found that restoring plant diversity does not necessarily restore animal diversity, but rather animals respond independently to fire and grazing (Guiden et al., in revision at PNAS. Future research will examine the potential for bison grazing to alter the behavior of seed predators: pilot data suggest that small mammals are more sensitive to predation risk in bison-grazed habitats, and consequently may consume fewer seeds.
|
Plants and herbivores in novel winter climates
In northern forests, snow provides an important refuge for plants and animals. Deep snow can shield organisms from cold and variable air temperatures, or hide organisms from their predators. Snowfall has declined across most of the Great Lakes region in the past 30 years, a trend that shows no sign of slowing down. Because long, snowy winters have characterized northern forests for millennia, continued climate change will expose northern plants and animals to winter conditions outside historic norms. Using snow-removal field experiments, my dissertation research showed that the loss of snow will likely amplify small-mammal seed predation (Guiden and Orrock, in review) and seedling herbivory (Guiden et al. 2018, Am. J. Bot, Guiden et al. 2018, Ecography) in northern temperate forests. However, we know little about basic animal behavior during winter, such as the ability of mice to switch from nocturnal to diurnal activity underneath the snow (Guiden and Orrock 2020, Animal Behaviour). This work could provide a better understanding of which tree species will thrive or decline in the forests of the future, and conditions that favor increased herbivore pressure on native trees. By considering the role of winter temperatures and snow depth, conservationists and foresters may be able to improve regeneration of important tree species as winter climates continue to change. |
Novel autumn phenology of invasive shrubs
The success of some invasive plant species is due to interactions between these invaders and native animals. This usually happens in two ways: 1) native animals provide some service to the invasive plant (a "mutualism") and/or 2) native animals use the invader as habitat. When invasive plants and native animals interact, it is usually native plants that pay the price. In the eastern US, invasive plants can have particularly strong effects in autumn. On average, invasive shrubs drop their leaves later than native shrub species. During fall, Amur honeysuckle is commonly browsed by deer, which disperse consumed seeds over long distances, providing a mutualism that spreads this invasive species (Guiden et al. 2015, Plant Ecology). However, the dense growth and long-lasting leaves of invasive shrubs also provides native animals with a safe refuge from predators during a season when such refuge is scarce. Native mice living in invaded habitats respond by using much more space throughout their habitat (Guiden et al. 2017, Ecology) and remaining active all night long, even during high-risk periods of bright moonlight (Guiden and Orrock 2019, Behavioral Ecology). This work will hopefully improve our understanding of the role these common mammals play in the invasion process, helping us anticipate which habitats or landscapes are vulnerable to invasion. Additionally, this research can tell us what these behavioral changes mean for native plants, and how continued invasion might alter forest diversity. Invasive shrub removal is a common restoration technique, and this work can inform how shrub removal at relatively small scales can change animal behavior. |
|