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Macromia alleghaniensis (Odonata: Macromiidae): New for Michigan, with clarifications of northern records
Abstract
An Alleghany River Cruiser, Macromia alleghaniensis Williamson, collected in Cass County, Michigan on 18 June 2014, represents the first record of the species for the state, as well as the northernmost unequivocal record in North America. Other records north of 40° latitude are clarified and discussed.
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The distributions of riverine dragonflies and damselflies (Insecta: Odonata) were modeled at the scale of individual river segments across the northeastern United States, a 784,982 km2 region spanning from Ohio, West Virginia, and Virginia northeast to Maine. The species distribution modeling approach was reviewed with respect to Odonata, and several modeling techniques were compared. Species locality data assigned only to U.S. county is prevalent in invertebrate databases, and it was found that using these data for modeling tends to overpredict the geographic distributions of species. Several techniques to compensate for geographic sampling bias, which is also a characteristic of these largely opportunisticly collected databases, were compared, though the optimum method (thinning data, biased background sampling, or no treatment) depended on the dataset. Watersheds and riparian zones are ecologically relevant for riverine organisms, and models with catchment- and local-scale predictors outperformed models based only on climate. This fine-scale modeling approach is appropriate for the conservation of freshwater diversity, because individual river segments containing suitable species habitat can be identified and prioritized. Climate change is expected to reduce the available habitat for riverine Odonata within the northeastern U.S., though some rivers may serve as climatic refugia, and conservation of these rivers and their watersheds is essential.
Species range shifts associated with environmental change or biological invasions are increasingly important study areas. However, quantifying range expansion rates may be heavily influenced by methodology and/or sampling bias. We compared expansion rate estimates of Roesel's bush-cricket (Metrioptera roeselii, Hagenbach 1822), a nonnative species currently expanding its range in south-central Sweden, from range statistic models based on distance measures (mean, median, 95th gamma quantile, marginal mean, maximum, and conditional maximum) and an area-based method (grid occupancy). We used sampling simulations to determine the sensitivity of the different methods to incomplete sampling across the species' range. For periods when we had comprehensive survey data, range expansion estimates clustered into two groups: (1) those calculated from range margin statistics (gamma, marginal mean, maximum, and conditional maximum: ˜3 km/year), and (2) those calculated from the central tendency (mean and median) and the area-based method of grid occupancy (˜1.5 km/year). Range statistic measures differed greatly in their sensitivity to sampling effort; the proportion of sampling required to achieve an estimate within 10% of the true value ranged from 0.17 to 0.9. Grid occupancy and median were most sensitive to sampling effort, and the maximum and gamma quantile the least. If periods with incomplete sampling were included in the range expansion calculations, this generally lowered the estimates (range 16–72%), with exception of the gamma quantile that was slightly higher (6%). Care should be taken when interpreting rate expansion estimates from data sampled from only a fraction of the full distribution. Methods based on the central tendency will give rates approximately half that of methods based on the range margin. The gamma quantile method appears to be the most robust to incomplete sampling bias and should be considered as the method of choice when sampling the entire distribution is not possible.
Climate change represents a major challenge for conservation in the future, and undermines protection within reserve boundaries. Freshwater biodiversity is still under-represented within reserves worldwide, and connectivity among reserves will become increasingly crucial if species are to persist under climate change.We tested the likely benefits of including predicted species distributions in systematic reserve design for rivers under climate change, and the impact of varying connectivity requirements on future representation.We used the modelled distribution of 126 east Australian Odonata to identify reserve networks using data for current or future (2055 and 2085) distributions either by filling gaps additively, or as separate targets in a single solution. We then assessed the potential improvements to species representation in the future by using different types of connectivity penalties that emphasised either longitudinal riverine connections or connections to all neighbouring sub-catchments.Solutions that did not include future distributions in the planning stages were 16 to 30% less likely to protect the same species by 2055 and 2085 respectively. Inclusion of species’ future distributions in the design phase leads to short-term increases in cost, but in the longer term fewer additional areas are required to meet targets and this strategy is likely to be significantly more efficient than implementing systematic design in stages. In addition, solely targeting riverine connectivity was significantly less likely to protect current species in the future than if cross-catchment connections were included.Synthesis and applications. Where protected areas can be expanded to assist species adaptation to climate change, significant gains in efficiency are possible if longer-term goals are considered when selecting sites. Furthermore, to improve the representation of species under future climates, reserve selection should consider inter-catchment connectivity, although the nature of optimal solutions will depend heavily on the range of taxa included, their dispersal capacity, and the availability of climatic refugia.This article is protected by copyright. All rights reserved.
Beginning in late summer 2010, the Neotropical dragonfly Tramea calverti Muttkowski, striped saddlebags, was observed in a major northward movement in eastern North America. This species appeared for the first time in three Great Lakes states and Canada (Ontario). A specimen from Michigan is the first and only voucher in the Great Lakes.
Two band-winged dragonlets, Erythrodiplax umbrata (Linnaeus), collected in Wayne County, Michigan on 6 October 2007 represent the first records for this genus and species in the state, as well as the northernmost record for the species.
This report is a contribution to the Ohio Odonata Survey. Three species previously unknown for Ohio are reported as new state records: Macromia georgina (Selys), 1878, Gomphaeschna furcillata (Say), 1839, and Libellula deplanata Rambur, 1842. These records increase the number of known Odonata from Ohio to 156 species and subspecies. Also reported are 611 new county records, significantly expanding our knowledge of distribution of these species in Ohio. Comments on early or late flight dates and/or species status are made for several species. These records are based upon recent collecting and re-examination of museum collections.
