Surveying amphibian communities along rivers to explore hypothesized environmental influences

<p><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><b><span lang="EN" new="" roman="" style="font-family:" times=""><span style="color:black">Tags/Keywords</span></span></b><span lang="EN" new="" roman="" style="font-family:" times=""><span style="color:black">: </span></span><span lang="EN" new="" roman="" style="font-family:" times="">Amphibians; Bioindicator; Environmental Factors; Resilience; Community Ecology; Survey; Field Course; River Field Studies Network</span></span></span></p> <p><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><b><span lang="EN" new="" roman="" style="font-family:" times=""><span style="color:black">Instructor Notes:</span></span></b> </span></span></p> <ol> <li><span style="font-size:12pt"><span style="color:black"><span style="font-family:Calibri,sans-serif"><u><span lang="EN" new="" roman="" style="font-family:" times="">Target audience:</span></u><span lang="EN" new="" roman="" style="font-family:" times=""> This lesson is appropriate for an introductory ecology laboratory for lower</span><span lang="EN" new="" roman="" style="font-family:" times="">-</span><span lang="EN" new="" roman="" style="font-family:" times="">level undergraduates or potentially upper level</span><span lang="EN" new="" roman="" style="font-family:" times="">-</span><span lang="EN" new="" roman="" style="font-family:" times="">undergraduates in a freshwater ecology course or similar course. No prior knowledge or skills are needed, although general understanding of freshwater ecosystems (e.g., basics of river food webs, ecological concepts such as abundance and species richness) and amphibian ecology is helpful. Some students, particularly non-Biology majors, may be uncomfortable with handling amphibians or sampling in flowing water or wetlands. Flexibility is therefore recommended so that all students can gain some exposure to animals and ecosystems without great discomfort. In upper</span><span lang="EN" new="" roman="" style="font-family:" times="">-</span><span lang="EN" new="" roman="" style="font-family:" times="">level courses and/or with additional time, the lesson may incorporate more complex analyses (e.g., statistical analyses in R) or allow exploration of more complex hypotheses (e.g., examining several sites across an environmental gradient).</span></span></span></span></li> <li><span style="font-size:12pt"><span style="color:black"><span style="font-family:Calibri,sans-serif"><u><span lang="EN" new="" roman="" style="font-family:" times="">Summary of the lesson</span></u><span lang="EN" new="" roman="" style="font-family:" times="">: Students will visit one or multiple sites in or along a river (e.g., backwater wetlands) or other suitable habitats for amphibians (e.g., ephemeral pools) and assess amphibian communities using </span><span lang="EN" new="" roman="" style="font-family:" times="">survey</span><span lang="EN" new="" roman="" style="font-family:" times=""> techniques (see </span><u><span lang="EN" new="" roman="" style="font-family:" times="">Logistics and materials needed</span></u><span lang="EN" new="" roman="" style="font-family:" times=""> below for details)</span><span lang="EN" new="" roman="" style="font-family:" times="">. Students will develop hypotheses for how environmental conditions (e.g., habitat type, temperature) influence amphibian communities. Students will thereby gain experience performing careful observations in a field study, gain understanding of the importance of amphibians in aquatic ecosystems, and gain practice developing hypotheses and evaluating them using field-collected data.</span></span></span></span></li> <li><span style="font-size:12pt"><span style="color:black"><span style="font-family:Calibri,sans-serif"><u><span lang="EN" new="" roman="" style="font-family:" times="">Approach to engagement</span></u><span lang="EN" new="" roman="" style="font-family:" times="">:</span></span></span></span></li> </ol> <p style="margin-left:48px"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><span lang="EN" new="" roman="" style="font-family:" times=""><span style="color:black">A number of initial discussion questions can be useful to engage students in this lesson</span></span><span lang="EN" new="" roman="" style="font-family:" times="">.</span></span></span></p> <ol style=""> <li style="list-style-type:none"> <ol> <li style="border:none"><span style="font-size:12pt"><span style="color:black"><span style="font-family:Calibri,sans-serif"><span lang="EN" new="" roman="" style="font-family:" times="">Why are amphibians important in aquatic ecosystems? How is their role unique compared to other organisms?</span></span></span></span> <ul> <li style="border:none; margin-left:24px"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><span lang="EN" new="" roman="" style="font-family:" times="">Possible response: Examples could include their role as consumers, common prey items, and hosts for parasites, with consequences for nutrient cycling and energy flows. Amphibians are relatively unique among amphibians due to their complex life cycle including both aquatic and terrestrial phases.</span></span></span></li> </ul> </li> <li style="border:none"><span style="font-size:12pt"><span style="color:black"><span style="font-family:Calibri,sans-serif"><span lang="EN" new="" roman="" style="font-family:" times="">How can studying amphibians be useful toward understanding ecosystem health? Are there as</span><span lang="EN" new="" roman="" style="font-family:" times="">pects of their biology that make them especially well-suited towards this goal?</span></span></span></span> <ul> <li style="margin-left:24px"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><span lang="EN" new="" roman="" style="font-family:" times="">Possible response: Amphibians have semipermeable skin and are sensitive to an array of environmental stressors, so that they can be especially useful as ecological indicators. In addition, due to their biphasic life cycle, they may be sensitive to disturbances in both aquatic and surrounding terrestrial habitats in unique ways.</span></span></span></li> </ul> </li> <li style="border:none"><span style="font-size:12pt"><span style="color:black"><span style="font-family:Calibri,sans-serif"><span lang="EN" new="" roman="" style="font-family:" times="">What are some environmental factors that influence their populations?</span></span></span></span> <ul> <li style="border:none; margin-left:24px"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><span lang="EN" new="" roman="" style="font-family:" times=""><span style="color:black">Possible response: </span></span><span lang="EN" new="" roman="" style="font-family:" times="">Amphibians are affected by a wide array of biotic and abiotic factors, including food availability, temperature, light levels, dissolved oxygen availability, pH, competitors, and predators.</span></span></span></li> </ul> </li> <li style="border:none"><span style="font-size:12pt"><span style="color:black"><span style="font-family:Calibri,sans-serif"><span lang="EN" new="" roman="" style="font-family:" times="">How are amphibian populations currently doing worldwide? In our area? </span></span></span></span> <ul> <li style="border:none; margin-left:24px"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><span lang="EN" new="" roman="" style="font-family:" times="">Possible response: Amphibians are the most threatened class of vertebrates globally. Many populations are undergoing declines due to factors such as habitat loss, pollution, and disease, particularly due to the fungal pathogen (<i>Batrachochytrium</i>) that has contributed to species extinctions in places like Central America and Australia. </span></span></span></li> </ul> </li> <li style="border:none"><span style="font-size:12pt"><span style="color:black"><span style="font-family:Calibri,sans-serif"><span lang="EN" new="" roman="" style="font-family:" times="">How might conditions upstream of a site and in the surrounding watershed influence habitat suitability for amphibians?</span></span></span></span> <ul> <li style="border:none; margin-left:24px"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><span lang="EN" new="" roman="" style="font-family:" times="">Possible response: Wetlands that serve as amphibian habitats are interconnected to the surrounding waterways and watershed. Human activities in the surrounding area can have direct and indirect impacts on the quality of the habitat.</span