Population dynamics of \u3cem\u3eLudwigia leptocarpa\u3c/em\u3e (Onagraceae) and some factors affecting size hierarchies in a natural population

Germination cohorts of Ludwigia leptocarpa, a semi-aquatic annual plant were marked in the field at time of establishment and followed through the 1981 and 1982 growing seasons at a site in southern South Carolina. Data from each cohort were pooled to determine demographic characteristics of the population as a whole, then analyzed separately to determine the effect of time on germination on survivorship, relative growth rate, and adult size. Changes in numbers of L. leptocarpa fit a Deevey Type II survivorship curve. This and other characteristics of the species classify it as ‘r-selected’. Aspects of the life history may reflect a ‘bet-hedging’ stratagem that ensures establishment. Differences in the time of germination are not responsible for differences in adult size, even when early-germinating plants have as many as 35 days more for growth than late germinators. This, and the fact that differences occur even within single cohorts, implies that factors other than time of germination must influence plant size

Featured Herbarium: BUT—The Friesner Herbarium of Butler University

Feature written by Rebecca Dolan on the BUT—The Friesner Herbarium of Butler University in the Vasculum

Bacon\u27s Swamp- Ghost of a Central Indiana Natural Area Past

Bacon’s Swamp was identified in the 1920s as a ca. 12 ha glacial kettle lake bog system at the southernmost limits of these habitats in Indiana. Located just 9.6 km from the center of Indianapolis, the site was all but destroyed in the mid-20th century by urban expansion. Prior to habitat conversion at the site, Bacon’s Swamp was a frequent location for Butler University ecology class field trips and student research projects. Herbarium specimens and published inventory records allow for analysis of the historical vegetation of Bacon’s Swamp using modern techniques. Floristic Quality Assessment applied to these historical records reveals Bacon’s Swamp was a regionally significant natural area, with a native Floristic Quality Index (FQI) value of 60 and a mean native Conservation Coefficient value of 4.2. Little of this unusual, high-quality habitat remains. A 2010 botanical inventory at the site documents decline in habitat with the loss of species that have a fidelity to high-quality habitat, with a corresponding drop in FQI to 20 and the addition of invasive non-native plants. Re-analysis of Bacon’s Swamp historical flora supports the view that it was a significant wetland natural area and floristically unique in Central Indiana

Red Giants in the Halo of the S0 Galaxy NGC 3115: A Distance and a Bimodal Metallicity Distribution

Using the Hubble Space Telescope, we resolve the red giant branch in the halo of the S0 galaxy NGC 3115. We measure magnitudes and $(V-I)$ colours for stars down to 1.5 magnitudes below the tip of the red giant branch. From the brightest stars we estimate a distance modulus $(m-M)_0=30.21 \pm 0.30$, corresponding to a distance of $11.0 \pm 1.5$ Mpc. This is in excellent agreement with the value $(m-M)_0=30.17 \pm 0.13$ determined from the planetary nebula luminosity function. Our results rule out the shorter distance modulus $(m-M)_0=29.65$ determined from surface brightness fluctuations. A histogram of $(V-I)$ colours shows a clear bimodality, indicating the presence of two distinct halo populations of roughly equal size. One has [Fe/H]$\sim -0.7$ and one has [Fe/H]$\sim -1.3$. This is the most distant galaxy in which a Population II halo has been resolved, and it is the first time a colour bimodality has been observed among the halo stars of any early-type galaxy.Comment: 15 pages, 4 figures. MNRAS, in pres

Demographic viability of populations of \u3cem\u3eSilene regis\u3c/em\u3e in midwestern prairies: relationships with fire management, genetic variation, geographic location, population size and isolation

We studied the demographic viability of populations of a long-lived iteroparous prairie perennial, Silene regia, in relation to management regimes, population sizes, geographical region (Ohio and Indiana vs. Missouri and Arkansas), degree of isolation and amount of genetic variation. Demographic data were collected from 16 populations for up to 7 years. This species has high survivorship, slow growth, frequent flowering and episodic seedling recruitment. Matrix projection methods were used to summarize population performance with and without recruitment. Median finite rates of increase by population varied from 0.57 to 1.82 and from 0.44 to 0.99, respectively. Populations with the highest rates of increase had been burned. Six of eight populations, for which stochastic modelling predicted persistence for 1000 years, included fire in their management. None of the five populations with predicted 100-year extinction probabilities of 100% was managed for conservation or burned. An intermediate group of three populations with at least 10% probability of extinction between 100 and 1000 years was not managed, but was none the less kept open by mowing and herbicide application. Analysis of composite elasticities showed that growth and fecundity terms were higher for growing (vs. declining) populations and that growth elasticity was higher in burned than unburned populations. Lack of burning shifts the elasticity spectrum from that typical of open habitat herbs (higher growth and fecundity elasticities) to values usually found for closed habitat herbs (higher survival elasticities). In multivariate analyses predicting finite rates of increase (with and without recruitment), fire management and region were the strongest predictors, followed by genetic variation, population size, isolation and interactions of population size and fire, and region and fire. Populations with the highest rates of increase were burned, eastern, more genetically diverse, larger and less isolated. Discrimination of populations with different extinction risks (three classes) was related mainly to fire, genetic variation and region. Most of these conclusions support conservation biology predictions that population viability will be highest in larger, less-isolated, more genetically diverse populations. However, management and geographic trends have overriding roles affecting demographic viability. Habitat fragmentation and genetic depletion have the potential to threaten residual prairie populations of S. regia, but lack of fire management appears to be the primary short-term threat

Floristic Inventory of Woollen’s Gardens Nature Preserve, Indianapolis, Marion County, Indiana, USA, With Quantitative Vegetation Sampling of Permanent Plots in 2003 and 2016

Urban forest fragments face challenges to habitat quality due to small size, isolation from larger natural areas, and close association with anthropogenic disturbance. Monitoring changes in vegetation can inform management practices targeted at preserving biodiversity in the face of these threats. Woollen’s Gardens is a high-quality mesic upland forest preserve in the city of Indianapolis, Indiana, USA, with a beechmaple older-growth forest and a significant display of showy spring wildflowers. The entire preserve was inventoried and quantitative vegetation analysis along seven 100 m transects was conducted in 2003 and again in 2016 to track changes. Data from both years document a high-quality flora with few non-native plants. Floristic Quality Index values for native species, derived from Floristic Quality Assessment, were 50.2 in 2003 and 47.3 in 2016. Native mean C-values of 4.5 and 4.3 for each year support that the site is comparable to the highest quality natural areas in central Indiana. Values declined little when non-natives were included, indicating non-natives are having little negative impact on the flora. Although non-natives comprised less than 10% of the flora, 11 of the 16 species are considered invasive in Indiana. In 2003, invasive Amur honeysuckle (Lonicera maackii) was among species in plots with the highest relative importance value. In 2016, invasive wintercreeper (Euonymus fortunei) was among these species. Limited public access to Woollen’s Gardens minimizes human disturbance, but invasive species are a threat to vegetation quality. Continuation of eradication efforts is strongly recommended before populations of these non-natives become more difficult to control

A new species of \u3cem\u3eStreptanthus\u3c/em\u3e (Brassicaceae) from Three Peaks in Lake County, California

Streptanlhus vernalis is a newly described species inhabiting serpentine rock outcrops in the Three Peaks area in Lake County, California. Morphological and allozyme data indicate that this taxon is related to the S. morrisonii complex

Taxonomy of \u3cem\u3eStreptanthus\u3c/em\u3e sect. \u3cem\u3eBiennes\u3c/em\u3e, the \u3cem\u3eStreptanthus morrisonii\u3c/em\u3e complex (Brassicaceae)

The Streptanthus morrisonii complex is a six-taxon group of closely related serpentine rock outcrop endemics from Lake, Napa, and Sonoma counties of California, USA. Two new subspecies (S. morrisonii subsp. kruckebergii and S. brachiatus subsp. hoffmanii) from Lake County, California, are described. The relationship of these taxa to others in the section is reviewed and descriptions and a key are provided