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Many restoration projects' success is not evaluated, despite available conventional ecological assessment methods. There is a need for more flexible, affordable, and efficient methods for evaluation, particularly those that take advantage of new remote sensing and geospatial technologies. This study explores the use of illustrative small unmanned aerial system (sUAS) products, made using a simple structure‐from‐motion photogrammetry workflow, coupled with a visual assessment protocol as a remote evaluation and ecological condition archive approach. Three streams were assessed in the field (“surface assessments”) using the Stream Visual Assessment Protocol Version 2 (SVAP2) and later illustrated in sUAS products. A survey of 10 stream experts was conducted to (1) assess the general utility of the sUAS products (high‐resolution video, orthomosaics, and 3D models), and (2) test whether the experts could interpret the products and apply the 16 SVAP2 elements remotely. The channel condition, bank condition, riparian area quantity, and canopy cover elements were deemed appropriate for remote assessment, while the riparian area quality, water appearance, fish habitat complexity, and aquatic invertebrate complexity elements were deemed appropriate for remote assessment but with some potential limitations due to the quality of the products and varying site conditions. In general, the survey participants agreed that the illustrative products would be useful in stream ecological assessment and restoration evaluation. Although not a replacement for more quantitative surface assessments when required, this remote visual approach is suitable when more general monitoring is satisfactory.
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Disentangling the visual cues of an evolutionary trap for aquatic insects
Abstract Aquatic insects use polarized light as a reliable visual cue for locating water surfaces given their need to locate sites for oviposition. However, many man-made surfaces polarize light more strongly than natural waterbodies creating an evolutionary trap in which many species preferentially lay their eggs on these polarizing artificial surfaces. Previous work has shown that the attractiveness of artificial surfaces to aquatic insects is diminished by adding non-polarizing gridlines to these surfaces. However, it is unknown how this mitigation affects aquatic insect preferences. We tested two alternative hypotheses about how aquatic insects judge the quality of potential oviposition sites. The visual averaging hypothesis states that insects judge the quality of a surface based on the percent area of the surface that is polarizing. An alternative hypothesis is that the quality of a polarizing surface is judged by the degree to which it is fragmented by non-polarizing elements. This experiment was conducted using oil tray traps as artificial polarizers whose percentage of polarizing area and the presence/absence of fragmentation was manipulated. Only Diptera were captured in sufficient numbers to test the hypotheses. Our findings for the dominant family in our captures, Dolichopodidae, were consistent with the visual averaging hypothesis – increasing the percent area that was non-polarizing significantly decreased captures, but the fragmentation of a polarizing surface had no significant effect on the number captured. For the other families of aquatic Diptera combined, however, there was a complex interactive effect of percent area of a surface that was polarizing and its fragmentation by non-polarizing gridlines. For the conservation of aquatic insects, these findings support the effectiveness of reducing the attractiveness of artificial polarizing surfaces such as solar panels by adding non-polarizing elements, but also show that for some aquatic insects, it is important to consider if the non-polarizing elements fragment the surface.
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- Award ID(s):
- 1659816
- PAR ID:
- 10657359
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Evolutionary Ecology
- Volume:
- 40
- Issue:
- 1
- ISSN:
- 0269-7653
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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