Butterfly (Lepidoptera: Lycaenidae, Nymphalidae, and Satyridae) Faunas of Three Peatland Habitat Types in the Lake Superior Drainage Basin of Wisconsin

The butterflies which complete their entire life cycle within peatland habitats were documented in the Lake Superior drainage basin of northwestern Wisconsin. Seventy peatlands were inventoried over the course of the 1996 growing season, and were classified as either muskeg, kettlehole, or coastal sites. Muskeg peatlands were of similar elevation to the surrounding uplands, possessed drier and more nutrient-poor substrates, and were typically larger than other peatland types. Kettlehole peatlands were wetter and had floating Sphagnum mats which fringed lake margins or were in depressions much lower than the surrounding uplands. Coastal peatlands were located in estuaries along the Lake Superior coast, and possessed relatively eutrophic, wet soils. Muskeg sites harbored the most diverse total fauna, and possessed the highest average number of taxa per site. A highly significant correlation between habitat size and butterfly richness was observed in both muskeg and kettlehole peatlands. The muskeg fauna included five taxa not found in other peatland habitats. These species have arctic-boreal affinities and reach their southern range limit in eastern North America on these sites

Butterfly (Lepidoptera: Lycaenidae, Nymphalidae, and Satyridae) Faunas of Three Peatland Habitat Types in the Lake Superior Drainage Basin of Wisconsin

The butterflies which complete their entire life cycle within peatland habitats were documented in the Lake Superior drainage basin of northwestern Wisconsin. Seventy peatlands were inventoried over the course of the 1996 growing season, and were classified as either muskeg, kettlehole, or coastal sites. Muskeg peatlands were of similar elevation to the surrounding uplands, possessed drier and more nutrient-poor substrates, and were typically larger than other peatland types. Kettlehole peatlands were wetter and had floating Sphagnum mats which fringed lake margins or were in depressions much lower than the surrounding uplands. Coastal peatlands were located in estuaries along the Lake Superior coast, and possessed relatively eutrophic, wet soils. Muskeg sites harbored the most diverse total fauna, and possessed the highest average number of taxa per site. A highly significant correlation between habitat size and butterfly richness was observed in both muskeg and kettlehole peatlands. The muskeg fauna included five taxa not found in other peatland habitats. These species have arctic-boreal affinities and reach their southern range limit in eastern North America on these sites

Poorly Vetted Conservation Ranks Can Be More Wrong Than Right: Lessons from Texas Land Snails

Setting priorities for scarce conservation dollars requires an accurate accounting of the most vulnerable species. For many invertebrates, lack of taxonomic expertise, low detectability, and funding limitations are impediments to this goal, with conservation ranks usually based on expert opinion, the published literature, and museum records. Because of biases and inaccuracies in these data, they may not provide an accurate basis for conservation ranks, especially when compared to de novo field surveys. We assessed this issue by comparative examination of these data sources in re-ranking the conservation status of all 254 land snail taxa reported from Texas, USA. We confirmed 198 land snail taxa, including 34 new state records. Our assessment of the entire land snail fauna of Texas resulted in (1) a near doubling of recommended Species of Greatest Conservation Need (SGCN) and (2) a 79% turnover in the makeup of SGCN taxa. Field sampling strongly outperformed museum and literature data in the encounter rate of both the entire fauna and all SGCN species, with the latter two demonstrating bias toward larger-bodied species. As a result, conservation priorities based solely on expert opinion and museum and literature records may be more wrong than right, with taxon-appropriate, targeted sampling required to generate accurate rankings

Radiocarbon dating loess deposits in the Mississippi Valley using terrestrial gastropod shells (Polygyridae, Helicinidae, and Discidae)

Small terrestrial gastropod shells (mainly Succineidae) have been used successfully to date late Quaternary loess deposits in Alaska and the Great Plains. However, Succineidae shells are less common in loess deposits in the Mississippi Valley compared to those of the Polygyridae, Helicinidae, and Discidae families. In this study, we conducted several tests to determine whether shells of these gastropods could provide reliable ages for loess deposits in the Mississippi Valley. Our results show that most of the taxa that we investigated incorporate small amounts (1–5%) of old carbon from limestone in their shells, meaning that they should yield ages that are accurate to within a few hundred years. In contrast, shells of the genus Mesodon (Mesodon elevatus and Mesodon zaletus) contain significant and variable amounts of old carbon, yielding ages that are up to a couple thousand 14C years too old. Although terrestrial gastropod shells have tremendous potential for 14C dating loess deposits throughout North America,weacknowledge that accuracy to within a few hundred years may not be sufficient for those interested in developing high-resolution loess chronologies. Even with this limitation, however, 14C dating of terrestrial gastropod shells present in Mississippi Valley loess deposits may prove useful for researchers interested in processes that took place over multi-millennial timescales or in differentiating stratigraphic units that have significantly different ages but similar physical and geochemical properties. The results presented here may also be useful to researchers studying loess deposits outside North America that contain similar gastropod taxa

Biotic homogenization or riparian refugia? Urban and wild land snail assemblages along a subtropical precipitation gradient

A noted impact of urbanization is the tendency for biotic homogenization, or the increase of similarity of geographically disparate communities. On the other hand, some urban habitats harbor biodiversity native to their region, a role potentially important in xeric landscapes, with irrigation increasing the coverage and availability of mesic habitats in an otherwise water-limited landscape. We assessed the relative importance of urban yards as agents of biotic homogenization or riparian refugia by characterizing community composition of Tamaulipan thornforest land snail assemblages across a pronounced precipitation gradient in far south Texas, USA. We quantified α- and β-diversity and assessed whether the land snail fauna of urban yards are more similar to each other across a precipitation gradient than they are to their wild counterparts, as well as determined the significance of moisture in driving Tamaulipan thornforest β-diversity, both in terms of turnover (changing species composition) and nestedness (species loss). Sites with both the wild and wet conditions had the highest values of species richness and abundance. Urban land snail communities were significantly homogenized, outweighing the influence of the precipitation gradient. We did not find urban yards served as a refuge for native, moisture-dependent, riparian snails. Our analyses find that turnover, not nestedness, is the largest contributor to β-diversity in these assemblages. Studies of urbanization should address regional spatial scales to quantify how urbanization modifies regional biodiversity arising from background environmental gradients. Such an approach could lead to improved understanding of how large metroplex areas could be used to maintain and even promote biodiversity

Additions to the Pteridophyte Flora of Iowa-IV

This report updates field collection records and summarizes nomenclatural changes of genera and binomials of species of Iowa pteridophytes based on the Flora of North America project. Botrychium simplex var. compositum, Gymnocarpium jessoense (Koidz.) Koidz. spp. parvulum Sarvela, Gymnocarpium Xhrittonianum (Sarvela) Pryer & Haufler, and Gymnocarpium Xintermedium Sarvela were recently added to the state flora. The flora now consists of 66 species, plus 7 hybrids, and 1 distinct form, for a total of 74 taxa. With the addition of 81 new county occurrence records, the Iowa pteridophyte flora now consists of 1754 county occurrence records. A data matrix of species/county occurrence records is provided

The Macroecology of Sustainability

Global consumption rates of vital resources suggest that we have surpassed the capacity of the Earth to sustain current levels, much less future trajectories of growth in human population and economy