Direct and indirect effects of the invasive Orconectes rusticus on native O. sanbornii in Ohio streams
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| Language: | English |
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The Ohio State University / OhioLINK
2016
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=osu1471626347 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu1471626347 |
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oai_dc |
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NDLTD |
| language |
English |
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NDLTD |
| topic |
Environmental Science Ecology biological invasions competition indirect effects Orconectes rusticus |
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Environmental Science Ecology biological invasions competition indirect effects Orconectes rusticus Johnson, Christopher A. Direct and indirect effects of the invasive Orconectes rusticus on native O. sanbornii in Ohio streams |
| author |
Johnson, Christopher A. |
| author_facet |
Johnson, Christopher A. |
| author_sort |
Johnson, Christopher A. |
| title |
Direct and indirect effects of the invasive Orconectes rusticus on native O. sanbornii in Ohio streams |
| title_short |
Direct and indirect effects of the invasive Orconectes rusticus on native O. sanbornii in Ohio streams |
| title_full |
Direct and indirect effects of the invasive Orconectes rusticus on native O. sanbornii in Ohio streams |
| title_fullStr |
Direct and indirect effects of the invasive Orconectes rusticus on native O. sanbornii in Ohio streams |
| title_full_unstemmed |
Direct and indirect effects of the invasive Orconectes rusticus on native O. sanbornii in Ohio streams |
| title_sort |
direct and indirect effects of the invasive orconectes rusticus on native o. sanbornii in ohio streams |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2016 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1471626347 |
| work_keys_str_mv |
AT johnsonchristophera directandindirecteffectsoftheinvasiveorconectesrusticusonnativeosanborniiinohiostreams |
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1719440650538057728 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu14716263472021-08-03T06:38:29Z Direct and indirect effects of the invasive Orconectes rusticus on native O. sanbornii in Ohio streams Johnson, Christopher A. Environmental Science Ecology biological invasions competition indirect effects Orconectes rusticus While the direct effects of non-native species as predators and competitors have been widely studied, the indirect effects of invasive species as novel prey are relatively unexplored. Yet, these novel energetic pathways are of great importance to long-term community response to biological invasions. Novel prey, as supplemental resources for native predators, can positively influence predator abundances. These changes in predator populations, and the associated shifts in predation risk, may result in concomitant effects upon native prey. These indirect effects may impose significant consequences on native prey populations. Aquatic systems are among the most impacted by biological invasions. Globally, freshwater crayfish are among the taxa most at risk to the effects of invasive species. In Ohio, the invasive rusty crayfish <i>(Orconectes rusticus)</i> has been implicated in the decline of a native congener, <i>O. sanbornii</i>. This research aimed to evaluate the influence of indirect effects of invasive <i>O. rusticus</i> on patterns of replacement of the native <i>O. sanbornii</i> in Ohio streams. I used a combination of field observations and experimental manipulations to fulfill three objectives. First, I quantified population demographics of <i>O. sanbornii</i> from streams invaded and not yet invaded by <i>O. rusticus</i>. I also measured and compared the body size of <i>O. rusticus</i> in streams where they currently co-occur with <i>O. sanbornii</i> or have replaced the native species. Second, I conducted a within stream tethering experiment to test for differences in predation risk between these two species. Finally, I used a laboratory experiment to explore the effect of predation risk, competitor identity, and the interaction of the two factors on the behavior of both <i>O. sanbornii</i> and <i>O. rusticus</i>. Results of field surveys indicated a significantly smaller average <i>O. sanbornii</i> body size in streams where they are found co-occurring with <i>O. rusticus</i>. However, there was no detectable difference in <i>O. rusticus</i> body size between streams where they currently co-occur versus streams which they have displaced <i>O. sanbornii</i>. There were no detectable differences in sex ratios or risk of predation across populations of either species. Results of the laboratory experiment indicated that both species respond to increased risk of predation with increased refuge use and reduced measures of activity. However, risk effects depended upon competitor identity. When competing with conspecifics, <i>O. sanbornii</i> significantly increased its use of refuge with elevated predation risk, while decreasing measures of activity. However, when competing against invasive <i>O. rusticus</i>, <i>O. sanbornii</i> only increased refuge use at high predation risk and demonstrated increased activity at zero and low risk. In contrast, <i>O. rusticus</i> decreased activity with elevated risk, an effect which was heightened when facing a heterospecific competitor. Native <i>O. sanbornii</i> suffers a tradeoff between managing the risk of predation versus cost of competing with a novel competitor. However, <i>O. rusticus</i> responds to competition from <i>O. sanbornii</i> in ways which are advantageous in risky environments. These results suggest that the behaviors of <i>O. rusticus</i> may allow the species to minimize the trade-off between finding food and avoiding predators and out-compete native <i>O. sanbornii</i>. 2016 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1471626347 http://rave.ohiolink.edu/etdc/view?acc_num=osu1471626347 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |