Invasive Plant & Carnivores
How does the invasive plant Arundo donax influence carnivore use of riparian habitat?
Recently published in Biological Invasions, see below for link
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Santa Clara River
This project takes place along the Santa Clara River in southern California. The Santa Clara river has some of the last remaining natural hydrology and riparian habitat in southern California. It is home to many native species, including the endangered Least Bell's Vireo, many other important migratory birds, and, of course, mammals such as coyotes, bobcats, and raccoons. |
Arundo donax
The Santa Clara River watershed is one of many regions in California that has been invaded by Arundo donax. Arundo is a tall, perennial reed-like grass, native to eastern Asia. It was introduced to California in the 1820s as an erosion control agent, and is now one of the most impactful invasive plants in riparian ecosystems. Arundo is highly competitive and grows in dense monotypic stands that are very difficult to remove. Previous studies have shown Arundo can negatively impact native bird and arthropod diversity, increase risk of fire, and alter stream hydrology. |
So, does Arundo alter carnivore use of habitat?
From our study: Yes! Overall, carnivore use of habitat was much higher in native patches than in mixed or Arundo (see figure to the right)
Why might habitat with more Arundo be lower quality for carnivores?
Two possible hypotheses may be:
From our study: Yes! Overall, carnivore use of habitat was much higher in native patches than in mixed or Arundo (see figure to the right)
Why might habitat with more Arundo be lower quality for carnivores?
Two possible hypotheses may be:
- Limited prey: Habitat with a high percentage of Arundo tends to have fewer other plants, which could lower the abundance of small herbivores, thus decreasing the availability of prey for carnivores and lowering their relative abundance (as displayed on the top path of the figure below).
- Limited movement and hunting: Arundo grows in dense patches, which can increase the energetic cost of movement for large-bodied animals, thus causing a decrease in carnivore relative abundance. This could lead to Arundo being a refuge for smaller prey (as displayed on the bottom path of the figure below).