Odonata as biological indicators of habitat quality in restored wetlands in the Arizona borderlands

Murrieta Molina, Bernardo (2021) Odonata as biological indicators of habitat quality in restored wetlands in the Arizona borderlands. Masters thesis, Northern Arizona University.

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Abstract

Climate change has led to severe impacts on aquatic habitats and biodiversity in the US-Mexico border region, with permanent streams, seasonal lakes, and playas drying intermittently or completely in recent decades. The purpose of this study was to assess Odonata as general indicators of ecosystem health, and to identify habitat-specialist taxa that could, if present, indicate the presence of habitat suitability or, if absent, a decline in habitat quality. Water sources in the Chiricahua Mountains region and nearby vicinities in the Southwest of Arizona were surveyed in 2020 for assemblage composition of adult Odonata. A total of 52 species (30 dragonfly and 22 damselfly species) were identified during the growing season. These species belonged to three families of Anisoptera, of which Libellulidae was dominant, and three families of Zygoptera. Adult abundances increased significantly during mid-summer months and decreased rapidly by September. Also, four families of Odonata nymphs were detected, with Libellulidae dominating the aquatic larval assemblage.Analysis of larval versus adult abundance data revealed high among-site variation in larval:adult ratios, with three general patterns over the field season. The first pattern is that some sites supported high species richness and large numbers of adult Odonata, but no nymphs whatsoever. The second pattern indicated that sites with intermediate area and habitat quality showed approximately equal larval:adult ratios. Lastly, late in the field season adults were largely absent, while larval abundances at most sites were unchanged, indicating high temporal variability in adult distribution, but relative constancy of larvae. Non-metric multidimensional scaling (NMDS) ordination indicated assemblage differences between lentic and lotic sites, and also revealed a third aquatic habitat, the “semi-lotic” type. In addition, the NMDS analysis fit the physical and water quality variables to see which are most closely associated with the overall ordination. Pearson correlation analysis identified positive but weak correlations among several physical and water quality variables. Such relationships may indicate changes in habitat quality. Dufrene-Legendre Indicator Species Analysis added additional resolution to the selection of potential indicator species. That analysis revealed the habitats for which particular individual species may serve as indicators. For example, Argia tonto and Hetaerina vulnerata were clear indicators of lotic habitats, while Enallagma civile and Anax junius were indicators of lentic habitats. Taken together, the results from ordination and indicator species analysis allowed me to identify a suite of relatively common species that were habitat specialists. Ten taxa were determined as candidates for an initial indicator assemblage. More study will lead to further refinement, and additional work on sampling protocols is needed to develop an efficient mixed-species monitoring approach for aquatic habitats. My results indicate that the Odonata can serve as indicators of habitat quality and environmental change. By selecting specialist species indicative of the different aquatic habitats (lentic, semi-lotic, lotic), and applying the suggested abundance criteria, individuals conducting aquatic habitat monitoring can develop an initial assemblage of indicator species, and refine that assemblage iteratively by adding additional species that are tied closely to specific habitats or habitat characteristics. My conclusions are preliminary, but are encouraging with respect to the use of Odonata as indicators of aquatic habitat quality. Using the Odonata as indicators can help refine and improve wetland restoration and management, leading to improved ecological, economic, and social wellbeing in increasingly water-challenged arid regions.

Item Type:	Thesis (Masters)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	Odonata; Dragonflies; Damselflies; Habitat; Wetlands; Borderlands; Chiricahua Mountains; Climate change
Subjects:	Q Science > QL Zoology
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of the Environment, Forestry, and Natural Sciences > School of Earth Sciences and Environmental Sustainability
Date Deposited:	03 Feb 2022 19:19
Last Modified:	03 Feb 2022 19:19
URI:	https://openknowledge.nau.edu/id/eprint/5646

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