Trans-Beringia taxa often present complex puzzles for taxonomists, a reflection of differing traditions and opinions, taxonomic approaches, and access to material from both sides of the Bering Strait. There is wide biological variation in perceived or circumscribed taxa whose populations are widespread within the regions and yet biogeographically isolated in Asia and/or America. The Claytonia arctica complex is one such example; it illustrates these issues well and has been dealt with by North American and Russian botanists in decidedly different ways. We reviewed specimens and examined the various taxonomic concepts of C. arctica through time and source publications. The relationships (alignments) among taxonomic concepts are presented in a graphical format. We found that much of the confusion related to C. arctica in Beringia stems from overlookingC. scammaniana Hultén sensu Hultén (1939), and placing too much emphasis on the woody caudex and perennation structures, during the creation of two taxonomic concepts: C. arctica Adams sensu Porsild and C. porsildii Jurtzev sensu Yurtsev. The C. arctica complex (in our current sense) is an evolutionary work in progress, resulting in partially differentiated races with much overlapping variability and intergradation of characters (particularly in C. scammaniana according to our current sense) that have not reached the level of stability (i.e., individuals may still intergrade freely) usually associated with the concept of species in other arctic lineages.

Sexual dichotomy in habitat selection during the nonbreeding season was studied in the rough-skinned newt Taricha granulosa from November 1970 to August 1973 on southern Vancouver Island. Field results show that in this area adult females normally migrate from breeding ponds to overwinter on land. Adult males normally remain permanently aquatic. Related observations on the reproductive cycle of T. granulosa show that females, who lay their eggs singly, deposit them for a period of a few days, followed by a period of nonegglaying. This process is repeated at intervals. Oviposition can occur from late April to July in this area. Females who were induced to ovulate in the laboratory each deposited three eggs per day for 5 days before opposition ceased. Thus the reproductive cycles of field and taboratory-acclimated females are correlated.

PremisePlant phenological shifts are among the clearest indicators of the effects of climate change. In North America, numerous studies in the northeastern United States have demonstrated earlier spring flowering compared to historical records. However, few studies have examined phenological shifts in the southeastern United States, a highly biodiverse region of North America characterized by dramatic variations in abiotic conditions over small geographic areas.MethodsWe examined 1000+ digitized herbarium records along with location‐specific temperature data to analyze phenological shifts of 14 spring‐flowering species in two adjacent ecoregions in eastern Tennessee.ResultsSpring‐flowering plant communities in the Blue Ridge and the Ridge and Valley ecoregions differed in their sensitivity to temperature; plants in the Ridge and Valley flower 0.73 days earlier/°C on average compared to 1.09 days/°C for plants in the Blue Ridge. Additionally, for the majority of species in both ecoregions, flowering is sensitive to spring temperature; i.e., in warmer years, most species flowered earlier. Despite this sensitivity, we did not find support for community‐level shifts in flowering within eastern Tennessee in recent decades, likely because increases in annual temperature in the southeast are driven primarily by warming summer (rather than spring) temperatures.ConclusionsThese results highlight the importance of including ecoregion as a predictor in phenological models for capturing variation in sensitivity among populations and suggest that even small shifts in temperature can have dramatic effects on phenology in response to climate in the southeastern United States.

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