Conservation of the Illinois flora: A climate change vulnerability assessment of 73 plant species

It will be important for land managers, ecological researchers and policymakers to understand how predicted climate changes may affect the flora of Illinois. A climate change vulnerability assessment was completed in 2011 for the162 Animal Species in Greatest Need of Conservation using NatureServe’s Climate Change Vulnerability Index (CCVI) tool. Here we selected 73plant species found in Illinois and calculated their relative vulnerabilities to predicted climate changes, also using the NatureServe CCVI tool. We selected species from several groups that we felt would be broadly representative of the Illinois flora. These groups included: rare plants, invasive plants, important prairie species, important woodland/savanna species, important forest species, and plants important to society. We compiled and entered data regarding both the species’ exposures to predicted climate changes and their sensitivities to those changes. Exposures were determined by overlapping species range maps for Illinois with maps of temperature and moisture (AET:PET) predictions for the middle of this century. Species sensitivities were determined by interviewing between 4 and 12 experts for each plant species. Experts answered questions found in the CCVI tool regarding the species’ biologies, ecologies and behaviors. Results for each individual survey were averaged for each species. Results fell into one of five vulnerability categories: Extremely Vulnerable, Highly Vulnerable, Moderately Vulnerable, Not Vulnerable/Presumed Stable, and Not Vulnerable/Increase Likely. Results for these 73species in Illinois fell into all 5 vulnerability categories, with the majority (67%) falling into the Presumed Stable category. The species most vulnerable to predicted climate changes were all of conservation concern; most were federal or state listed species. Native species tended to be more vulnerable than non-natives, and plants important to prairies, savannas and forests were equally vulnerable to predicted changes. The four species were ranked as likely to increase in population size or range extent due to predicted climate changes were: Ailanthus altissima(tree of heaven), Ambrosia artemisiifolia(ragweed), Microstegium vimineum(Japanese stiltgrass) and Toxicodendron radicans(poison ivy). We advocate for 8 important next-steps to ensure adequate conservation of Illinois plants in a future with climate change, based on the findings of this report: 1) Investigate the climate change vulnerabilities of all rare plants in Illinois. Rare plants are the most vulnerable group of species in this report. 2) Prioritize research on plants’ abilities to phenologically track changes in seasonality, population genetics, species interactions, dispersal distances, thermal and hydrological tolerancesand soil preferences/tolerances. 3) Continue to monitor population trends. Increase capacity to monitor species with the most uncertain responses to climate changes, the most vulnerable species, and all rare species. 4) Monitor invasive speciesfor changes in populations and behavior. Assess all invasive species using NatureServe’s CCVI tool or another tool. 5) Increase connectivity between natural areas. Increase acreage of natural areas. 6) Managers, policymakers, researchers and the public shouldwork together to fully consider the role that assisted migration should or should not play in Illinois plant conservation. 7) Compile work done by various agencies and NGOs on the climate change vulnerabilities of Illinois species and ecosystems to detect trends, and to identify appropriate research, management and policy priorities. 8) Use adaptive management approaches to care for natural areas in Illinois in order to best achieve land management goals in an uncertain future.Illinois Natural History SurveyIllinois Department of Natural ResourcesIllinois Department of Transportationunpublishednot peer reviewedOpe

Genetic Characterization of Invasion and Hybridization: A Bittersweet (Celastrus spp.) Story

Biological invasions threaten native biodiversity and invasions that involve reproductive interference, such as hybridization, can be especially detrimental to the persistence of native species. One general objective of my dissertation research was to determine if the decline of a North American vine, Celastrus scandens, in the eastern portion of its native range is related to reproductive interference from an introduced congener, C. orbiculatus. The second general objective was to examine how anthropogenic factors, such as commerce and alteration of biogeochemical cycles, contribute to invasion by C. orbiculatus. I used genetic markers and field observation to survey individuals across the USA to determine the prevalence of wild hybrids. I also collected seeds from both species and tested the hybrid status of resulting seedlings. Hybrids were widespread in the wild, but only 8% of non-native genotypes surveyed were hybrids. Unidirectional pollen flow was evident, as all 20 hybrids tested had maternally inherited markers indicative of C. scandens. Additionally, 51% of C. scandens seeds were hybrids, compared to 1.6% of C. orbiculatus seeds. Hybridization rate in C. scandens was negatively associated with distance to the nearest staminate C. orbiculatus. I used genetic markers to test the species identity of commercially available plants marketed as C. scandens and found that the majority of samples and named varieties obtained were actually C. orbiculatus. Finally, I used experimental enrichment trials to simulate the elevated atmospheric carbon dioxide and increased nitrogen deposition expected in the future. Biomass allocation in both species responded to carbon dioxide and competition treatments, but only C. orbiculatus responded to increased nitrogen. The results suggest increased phenotypic plasticity in C. orbiculatus, and that the invasive vine may be better able to cope with changes to biogeochemical cycles of the future. Overall, the work in this dissertation reveals factors involved in the decline of C. scandens and successful invasion of C. orbiculatus. Human commerce, changing biogeochemical cycles, and especially reproductive interference likely played a role in the decline of the native vine and spread of the invasive congener in the past, and their influence will likely increase in the future

Assessing the Reproductive Ecology of a Rare Mint, <i>Macbridea alba</i>, an Endangered Species Act Protected Species

Many rare plant species lack up-to-date research about their reproductive ecology, which challenges effective in situ and ex situ conservation, particularly in the face of ongoing environmental and anthropogenic changes. For protected species, outdated and incomplete information also creates barriers to successful recovery planning and delisting. In this study, we gathered a range of reproductive metrics for the federally threatened and state endangered Florida endemic mint, Macbridea alba Chapman (Lamiaceae). We collected data at seven populations within Apalachicola National Forest (Florida, USA) and conducted germination trials to estimate reproductive potential. Additionally, we observed a previously undocumented lepidopteran seed predator for the species and confirmed the occurrence of vivipary. The seed set was low with less than 20% of flowers per inflorescence producing seed across populations; however, germination was high with more than 60% of seeds germinating in five of seven populations. When comparing our results to previous research conducted more than 20 years ago, the results were similar overall (i.e., germination, vivipary); however, new information emerged (i.e., herbivore pressure). As M. alba undergoes reassessment as a potential candidate for delisting from the Endangered Species Act (ESA) list, this information is critical for assessing recovery goals and decisions regarding the species’ protected status. For recovery needs related to propagation and reintroduction, these results can inform future seed collection and propagation efforts for the species

Reproductive trade-offs maintain bract color polymorphism in Scarlet Indian paintbrush (Castilleja coccinea).

Populations of scarlet Indian paintbrush (Castilleja coccinea) in the Midwestern United States exhibit a bract color polymorphism, with each population having predominantly yellow or scarlet bracts. We investigated a possible mechanism for this maintenance of bract color polymorphism in C. coccinea by conducting hand-pollination experiments in two nearby populations, one predominantly yellow and one predominantly scarlet. The hand-pollination treatments were either self-pollination or cross pollination using pollen from within and between populations. Both color morphs were used as pollen donors for the within and between crosses. We found that both color morphs of C. coccinea were self-compatible. When the scarlet morph was the maternal plant it had higher seed set. When pollinators were excluded, the yellow morph outperformed the scarlet morph in fruit set and seed set. The apparent trade-offs between a higher reproductive output in the scarlet morph and a reproductive assurance advantage in the yellow morph may explain the maintenance of the polymorphism in C. coccinea. While many previous studies have provided evidence for pollinator preference playing a role in floral color polymorphism, the results of the current study indicate that reproductive assurance, which would be important for fluctuations in pollinator abundance or colonizing new areas, may act as a selective agent to maintain such polymorphisms

Heterospecific pollination by an invasive congener threatens the native American bittersweet, Celastrus scandens.

Invasive plants have the potential to interfere with native species' reproductive success through a number of mechanisms, including heterospecific pollination and hybridization. This study investigated reproductive interactions between a native North American woody vine (American bittersweet, Celastrus scandens) and an introduced congener (oriental bittersweet, C. orbiculatus). The decline of C. scandens in the eastern portion of its range is coincident with the introduction and spread of C. orbiculatus, and the two species are known to hybridize. The relationship between proximity and floral production of conspecific and heterospecific males on fertilization and hybridization rates was measured at a field site in northwestern Indiana, USA where both species occur and reproduce. We found that the invasive vine had an extreme advantage in both male and female floral production, producing nearly 200 times more flowers per staminate plant and 65 times more flowers per pistillate plant than the native. Using nuclear microsatellite DNA markers we found that hybridization rates were asymmetric; 39% of the C. scandens seeds tested were hybrids, compared to only 1.6% of C. orbiculatus seeds. The asymmetric hybridization rates were likely not solely due to greater abundance of C. orbiculatus pollen because experimental hand crosses revealed that C. scandens had a higher rate (41%) of heterospecific fertilization than C. orbiculatus (2.4%). We previously reported that few hybrids were observed in the wild, and hybrids had greatly reduced fecundity. Thus, in our system, the threat posed by heterospecific pollen is not replacement by hybrids or introgression, but rather asymmetric reproductive interference. Reproductive interference extended to distances as great as 100 meters, thus, efforts to conserve the native species must reduce its exposure to C. orbiculatus over a relatively large spatial scale

Interspecific and Intraspecific Pollination Patterns of Valley Oak, Quercus Lobata, in a Mixed Stand in Coastal Central California

Pollination patterns within Quercus lobata and interspecific hybridization between Q. lobata and Quercus douglasii were studied in a coastal central California mixed woodland. We first identified hybrids by means of microsatellite genotyping and assignment tests. Hybrids were rare, both among adults (4 of 190, 2.1%) and among acorns collected from Q. lobata trees (6 of 392, 1.5%). These low rates of hybridization at both early and late life history stages suggest that fertility barriers, rather than natural selection against hybrids, limit hybridization between these two species. However, hybrid adults, although rare, may facilitate gene flow between the two species. Acorns collected from a hybrid tree had both Q. lobata pollen donors (11 of 30, 37%) and Q. douglasii or hybrid pollen donors (19 of 30, 63%). After removing hybrid acorns from the analysis, we used paternity assignment to track pollination patterns within Q. lobata. Of 108 acorns, only 32 (30%) were assigned to candidate pollen donors within 200 m of the maternal tree, indicating that the majority of effective pollen travels more than 200 m. Individual trees had acorn crops with many different sires and an average effective number of pollen donors (Nep) of 219 per tree. Indirect methods using correlated paternity estimated mean pollination distances of ~100 m and mean Nep of 5.2 per tree, values much lower than those derived directly from paternity assignments

Drivers of synchrony of acorn production in the valley oak (Quercus lobata) at two spatial scales

We investigated spatial synchrony of acorn production by valley oaks (Quercus lobata) among individual trees at the within-population, local level and at the among-population, statewide level spanning the geographic range of the species. At the local level, the main drivers of spatial synchrony were water availability and flowering phenology of individual trees, while proximity, temperature differences between trees, and genetic similarity failed to explain a significant proportion of variance in spatial synchrony. At the statewide level, annual rainfall was the primary driver, while proximity was significant by itself but not when controlling for rainfall; genetic similarity was again not significant. These results support the hypothesis that environmental factors, the Moran effect, are key drivers of spatial synchrony in acorn production at both small and large geographic scales. The specific environmental factors differed depending on the geographic scale, but were in both cases related to water availability. In addition, flowering phenology, potentially affecting either density-independent pollination failure (the pollination Moran effect) or density-dependent pollination efficiency (pollen coupling), plays a key role in driving spatial synchrony at the local geographic scale

Appendix C. NMS ordination of bird counts (square-root transformed) from 1396 BBS routes.

NMS ordination of bird counts (square-root transformed) from 1396 BBS routes

Appendix D. Relationships between community characteristic pairs modeled by multiple adaptive regression splines (MARS).

Relationships between community characteristic pairs modeled by multiple adaptive regression splines (MARS)