Conservation Assessment and Prioritization of Odonata in the Northeast

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Conservation Assessment and Prioritization of Odonata in the Northeast

The New York Natural Heritage Program and fellow contributors recently completed a region-wide conservation assessment of Odonata that was funded by the Regional Conservation Needs Grants program. The prioritization framework for 228 species of dragonflies and damselflies occurring in the northeastern US (Virginia to Maine) applies consistent and comprehensive criteria across all states to identify which species are most important regionally as well as the most vulnerable. This work can help direct limited state and regional resources toward conservation actions that benefit Odonata and their habitats and thereby guide implementation of State Wildlife Action Plans (SWAPs).

Odonates, dragonflies and damselflies, are valuable biological indicators of freshwater ecosystem integrity and climate change. Approximately 18 percent of odonates in the US are considered rare and vulnerable to extirpation or extinction. Recognition of northeastern North America as both a hotspot of odonate diversity, and a region of historical and growing threats to freshwater ecosystems, highlights the urgency of developing a comprehensive conservation assessment of the Northeast's resident odonate species.

The Odonate prioritization framework was developed from a modified version of NatureServe's methodology for assessing conservation status ranks by assigning a single, regional vulnerability metric (R-rank) reflecting each species' degree of relative extinction risk in the northeastern US. This newly formulated vulnerability assessment was combined with an updated analysis of the degree of endemicity (percent of the species' US and Canada range within the Northeast) as a proxy for regional responsibility, thereby deriving a list of species of combined vulnerability and regional management responsibility.

The dataset contains 248,059 records, with data from all NEAFWA states. The single vulnerability rank (R-rank) is based on five factors: three rarity factors (range extent, area of occupancy, and habitat specificity), one threat factor (vulnerability of occupied habitats), and one trend factor (relative change in range size). This yielded a regional vulnerability rank (R-rank) for each species, ranging from R1 (most vulnerable) to R5 (least vulnerable). Overall, 18 percent of our region's odonate fauna is imperiled (R1 and R2) and peatlands, low gradient streams and seeps, high gradient headwaters, and larger rivers that harbor a disproportionate number of these species should be considered as priority habitat types for conservation, monitoring, and management.

The prioritization framework could be used to inform the strategic allocation of limited state and federal conservation resources and help foster collaborations across state lines to implement similar goals for conserving regionally at-risk Odonata. More information on the project and a link to the final report is available on the RCN website. (mg)

January 16, 2015