Limited Range-Filling Among Endemic Forest Herbs of Eastern North America and Its Implications for Conservation With Climate Change

Biodiversity hotspots host a high diversity of narrowly distributed endemic species, which are increasingly threatened by climate change. In eastern North America, the highest concentration of plant diversity and endemism occurs in the Southern Appalachian Mountains (SAM). It has been hypothesized that this region served as a refugium during Pleistocene glacial cycles and that postglacial migration northward was dispersal limited. We tested this hypothesis using species distribution models for eight forest herb species. We also quantified the extent to which the geography of suitable habitat shifted away from the current range with climate change. We developed species distribution models for four forest herb species endemic to the SAM and four that co-occur in the same SAM habitats but have broader ranges. For widespread species, we built models using (1) all occurrences and (2) only those that overlap the SAM hotspot in order to evaluate the extent of Hutchinsonian shortfalls and the potential for models to predict suitable habitat beyond the SAM. We evaluated the extent to which predicted climatically suitable areas are projected to shift away from their current ranges under future climate change. We detected unoccupied but suitable habitat in regions up to 1,100 km north of the endemic species’ ranges. Endemic ranges are disjunct from suitable northern areas due to a ∼100–150 km gap of unsuitable habitat. Under future climate change, models predicted severe reductions in suitable habitat within current endemic ranges. For non-endemic species, we found similar overall patterns and gap of unsuitability in the same geographic location. Our results suggest a history of dispersal limitation following the last glacial maximum along with an environmental barrier to northward migration. Conservation of endemic species would likely require intervention and assisted migration to suitable habitat in northern New England and Canada

n-Culturals, the next cross-cultural challenge: introducing a multicultural mentoring model program

This article advances current conceptualizations of multicultural identities by identifying constituent elements of multicultural identity as knowledge, identification, internalization, and commitment. This new conceptualization is labeled n-Culturalism and posits that there are individuals who operate at the intersection of multiple cultures by maintaining salience of their multiple cultural identities. We illustrate that n-Culturals are assets to organizations because they are creative synthesizers that are able to facilitate organizational goals and can also serve as models for others who are struggling in a multicultural environment. This article provides some solutions to managing multicultural challenges in organizations, such as conflicting values and identities. It also offers solutions on how individuals and organizations can leverage their identities in relation to the multiculturalism continuum to achieve desired workplace outcomes. Further, we introduce the multicultural mentor modeling program for organizations, which, if implemented, can help struggling multiculturals to address challenges in their social cognition and to develop appropriate and effective behaviors in and outside of the workplace

Of Mutualism and Migration: Will Interactions with Novel Ericoid Mycorrhizal Communities Help or Hinder Northward Rhododendron Range Shifts?

Rapid climate change imperils many small-ranged endemic species as the climate envelopes of their native ranges shift poleward. In addition to abiotic changes, biotic interactions are expected to play a critical role in plant species’ responses. Below-ground interactions are of particular interest given increasing evidence of microbial effects on plant performance and the prevalence of mycorrhizal mutualisms. We used greenhouse mesocosm experiments to investigate how natural northward migration/assisted colonization of Rhododendron catawbiense, a small-ranged endemic eastern U.S. shrub, might be influenced by novel below-ground biotic interactions from soils north of its native range, particularly with ericoid mycorrhizal fungi (ERM). We compared germination, leaf size, survival, and ERM colonization rates of endemic R. catawbiense and widespread R. maximum when sown on different soil inoculum treatments: a sterilized control; a non-ERM biotic control; ERM communities from northern R. maximum populations; and ERM communities collected from the native range of R. catawbiense. Germination rates for both species when inoculated with congeners\u27 novel soils were significantly higher than when inoculated with conspecific soils, or non-mycorrhizal controls. Mortality rates were unaffected by treatment, suggesting that the unexpected reciprocal effect of each species’ increased establishment in association with heterospecific ERM could have lasting demographic effects. Our results suggest that seedling establishment of R. catawbiense in northern regions outside its native range could be facilitated by the presence of extant congeners like R. maximum and their associated soil microbiota. These findings have direct relevance to the potential for successful poleward migration or future assisted colonization efforts

Fruit Production Per Plant in Long-Term Study of Population Dynamics of Clarkia xantiana ssp. xantiana at 35 Populations in the Kern River Valley, California, USA from 2006 to 2017

The dataset (Data File Name: “Datafile_Fruit_Number_per_Plant.csv”) describes the fruit production per plant for up to 150 plants for each of the 35 populations followed in a long-term demographic study of Clarkia xantiana xantiana in Ker Co., CA. At each site, in each year, the number of fruits per plant was recorded on up to 150 plants per population. From 2006-2012, fruit number per plant was scored as the sum of undamaged fruits plus the “undamaged fruit equivalents” of damaged fruit. For example, if a plant had 2 damaged fruits, where half of each fruit was missing, the number of undamaged fruit equivalents was scored as 1, and added to the number of undamaged fruits. From 2013-2017, undamaged and damaged fruits were scored separately.Documentation of data collected on fruit production per plant in long-term study of population dynamics of Clarkia xantiana ssp. xantiana at 35 populations in the Kern River Valley, California, USA from 2006 to 2017.National Science Foundatio

Survivorship and Fecundity Data Collected in Long-Term Study of Demography of Clarkia xantiana ssp. xantiana at 20 Populations in the Kern River Valley, California, USA from 2006 to 2017

The datafile (Data File Name: “Datafile_Survivorship_Fecundity.csv) contains data for long-tern study of the demography of Clarkia xantiana xantiana in Kern Co., CA for 20 populations from 2006 to 2017. The dataset includes data on survivorship and fecundity of plants in permanent plots that were followed from germination to fruiting. At each site, 30 permanent plots of 0.5 m2 were established in 2006 along 4-6 transects. Each year, the number of seedlings in each permanent plot was recorded in February, the number of surviving fruiting plants and the average number of fruits per plant in each plot with fruiting plants were recorded in June. In 2006, only a subset of permanent plots were monitored for seedling germination, and fruit number per fruiting plant was not recorded. From 2006-2012, fruit number per plant was scored as the sum of undamaged fruits plus the “undamaged fruit equivalents” of damaged fruit. For example, if a plant had 2 damaged fruits, where half of each fruit was missing, the number of undamaged fruit equivalents was scored as 1, and added to the number of undamaged fruits. From 2013-2017, undamaged and damaged fruits were scored separately.Survivorship and fecundity data collected in long-term study of demography of Clarkia xantiana ssp. xantiana at 20 populations in the Kern River Valley, California, USA from 2006 to 2017.National Science Foundatio

Site Characteristics and Climate in Long-Term Study of Population Dynamics of Clarkia xantiana ssp. xantiana at 35 Sites in the Kern River Valley, California, USA from 2006 to 2017

Site locations and environmental variables of 35 populations of Clarkia xantiana ssp. xantiana where plant density and fruit production have been measured in a long term demographic study. The datafile (Data File Name: Datafile_Site_Environment.csv) details the full names of the sites, locality information, lat/long locations, slope, elevation, soil parent material, and radiation factors. The README file describes all of the column names in detail.Site locations and environmental variables of 35 populations of Clarkia xantiana ssp. xantiana where plant density and fruit production have been measured in a long term demographic study.National Science Foundatio

Fruit Herbivory on Individual Plants in Long-Term Study of Population Dynamics of Clarkia xantiana ssp. xantiana at 26 sites in the Kern River Valley, California, USA from 2001 to 2015

Dataset (Data File Name: Datafile_Site_Herbivory.csv) describes the level of herbivory on plants from populations that were part of the long-term demography study of Clarkia xantiana xantiana in Kern Co., CA from 2001-2015. Fruit production and fruits damaged on individual plants from 26 sites across years 2001 - 2015 (sites differ in number of years for which data have been collected).Documentation of fruit herbivory on individual plants in long-term study of population dynamics of Clarkia xantiana ssp. xantiana at 26 sites in the Kern River Valley, California, USA from 2001 to 2015.National Science Foundatio

Fruiting Plant Number in Long-term Study of Population Dynamics of Clarkia xantiana ssp. xantiana at 35 Populations in the Kern River Valley, California, USA from 2006 to 2017

Datafile (Data File Name: “Datafile_Fruiting_Plant_Density.csv) describes the fruiting plant number in quadrats followed on permanent transects for long-term demographic study of Clarkia xantiana xantiana from 2006 to 2017. At each site, in each year, fruiting plant number was counted in between 30 and 150 0.5 m2 quadrats distributed haphazardly throughout site. The number of quadrats depends on the areal extent of the population. For the 20 populations included in the detailed demography studies, data from 30 permanent plots are included.Documentation of data collected on fruiting plant number per 0.5m2 in long-term study of population dynamics of Clarkia xantiana ssp. xantiana at 35 populations in the Kern River Valley, California, USA from 2006 to 2017National Science Foundatio

The Effect of Various Stratification Lengths on Seed Sources of Ambrosia artemisiifolia Across Latitudes

Faculty advisor: David A. MoellerSeeds dormancy, a period of ceased physiological activity, is an adaptive trait promoting survival of seeds. Many plants exhibit different germination rates when seeds from various locations where seeds exposed to winter length and temperatures of their origins, are treated to equal amount of cold stratification length. This particular trait is expressed in common ragweed (Ambrosia artemisiifolia). Ragweed has high reproduction of dormant seeds that persist in the soil for many years while maintaining germination ability. Seeds are dependent on environmental conditions such as day length, temperature and humidity to break seed dormancy. That way, the dependence of seeds on environmental condition acts as a monitor system to determine the optimal germination timing and avoid improper environmental conditions. One of the most crucial environmental conditions for ragweed seeds is stratification or a period of cold temperatures, which is the first process that induces the dormancy and later promotes germination. Ragweed seeds collected from various locations corresponding to different latitudes may have different germination rates because of different temperatures and stratification from their own habitats. A study by Sorenson et al. (1990) indicated northern seeds of species western larch (Larix occidentalis Nutt.) have higher germination rates under longer stratification lengths. In the other hand, a study by Karlsson et al. (2007) indicated South African, where maintain high temperatures, seeds of species Papaver aculeatum have higher germination rates under warmer stratification. Accordingly, ragweed seeds from northern locations may require longer stratification and colder temperature to break dormancy because of its strong dormant. By contrast, seeds from southern locations may not require such long periods of stratification for germination because they lack extended winters. As difference in germination rates from different seed populations can be evident in response to various stratification lengths with fixed temperature, in this experiment I investigated the effect of different stratification lengths on germination rates of seeds from populations with different winter length.This research was supported by the Undergraduate Research Opportunities Program (UROP)