MODELING THE ABUNDANCE AND DISTRIBUTION OF TERRESTRIAL PLANTS THROUGH SPACE AND TIME

Anthropogenically-driven changes threaten ecosystems and species over regional to global scales. I addressed several questions related to how species ranges will respond to these changes over large spatial and temporal extents to better understand what determines where a species occurs. First, I modeled presence and abundance of two widespread invasive plants in the southwest U.S. under current and projected future climatic conditions, from which I inferred impact risk. These results provide more insight than presence modeling alone and highlight the possibility of increased invasion pressure in the future. Second, I tested the assumption that expert-based climatic tolerance data will better reflect a species’ physiological constraints than widely available herbarium data. I compared climatic ranges derived from herbarium data to those from expert-based data for over 1,800 terrestrial plant species. This research indicates that herbarium records provide more robust estimates of climatic tolerance, especially for widespread forbs and grasses. Third, I leveraged a unique spatial percent cover dataset to model potential sagebrush cover under current and future climate in the western U.S. The sagebrush ecosystem characterizes shrublands of the intermountain western U.S. and provides habitat for many obligate species but is threatened by several forms of global change. We used potential sagebrush cover to estimate habitat for five sagebrush-obligate species. The results identify regions most likely to support sagebrush and sagebrush-obligate species in the context of climate change. Finally, I addressed questions related to the spatial extent and landscape configuration of non-native Pinus in Chile. Pinus species are used in large plantations but have spread into surrounding landscapes and established invasive populations. In southern Chile, the extent of plantations and invasion is unknown, although the threat of invasion is well documented. Results from this study suggest that: 1) areas with high relief and high or low elevation might be less invasion-prone; 2) invasion risk might be lower than assumed given the prevalence of invasion-resistant native forest; and 3) the landscape should be monitored for new invasion sites stemming from isolated pine patches

The Effect Of Climate Change On The Distributions Of Invasive Plants And Their Associated Biological Control Agents In North America

Climate change has the potential to alter the size, shape, and location of species’ distributions. As a result, the interactions between species are also likely to be impacted as novel species encounter each other and historical community assemblages are broken apart. To quantify the impact of distributional changes as a result of climate change on interacting species, distribution maps were produced for three species of invasive plant and their associated biological control agent at three time periods: current, 2050, and 2080. For each of the future time periods, two distribution maps were created for each species, representing the minimum and maximum emission scenarios considered. The area of the projected future distributions for each species was compared to the current distributions. Percent change in area of distribution was calculated to determine the effect of climate change on the distributions of individual species. The total area of overlap in the distribution of plants and their biological controls for each of the time periods and emission scenarios also was calculated and percent change from the current distribution was used to quantify the effect of climate change on the species interactions. The distributions of the invasive plant species do not follow a consistent trend across models. The distribution of St. Johnswort (Hypericum perforatum Linnaeus, 1753) is expected to increase by 2050, then decrease to an area smaller than the current distribution by 2080. Leafy spurge (Euphorbia esula Linnaeus, 1753) is predicted to have larger distributions by 2080 under both emission scenarios, although only the minimum emission scenario predicts an initial decrease from the current distribution to that expected for 2050. The distribution of yellow toadflax [Linaria vulgaris (Miller, 1768)] is expected to decrease under both emission scenarios by 2080. The distributions of two of the biological control agents (BCAs), Klamath weed beetle [Chrysolina quadrigemina (Suffrian, 1851)] and toadflax moth [Calophasia lunula (Hufnagel, 1766)], are expected to increase by 2080. For both future time periods and emission scenarios, the distribution of leafy spurge hawk moth [Hyles euphorbiae (Linnaeus, 1758)] is expected to decrease from its current area. The area of overlap between two pairs of species (St. Johnswort and the Klamath weed beetle; yellow toadflax and the toadflax moth) is predicted to increase over time. This indicates that the distributions of the invasive species and their associated BCAs will overlap to a greater extent than currently and the BCAs have the potential to remain viable control mechanisms. The area of overlap between leafy spurge and the leafy spurge hawk moth is expected to decrease over time, indicating that the distributions of the species are not likely to respond similarly to climate change. As a result, the leafy spurge hawk moth might not be a suitable control mechanism for leafy spurge in the future. Because of data limitations, the results of this work are applicable to basic understanding of the systems and species involved. However, similar work has the potential to lead to a better understanding of the impact of biotic interactions on invasive and non-native species. In smaller geographic extents, similar research could help prioritize management of invasion by identifying those species that are expected to have increased distributions and escape from their BCA as a result of future climate change

Providing Experimental Support for Mtert as an Adult Neural Stem Cell Marker Using a Triple Transgenic Mouse Line

Mouse telomerase reverse transcriptase (mTERT) is a gene that is expressed by cells that need to continually divide without the characteristic shortening of telomeres that accompanies DNA replication. Here we provide experimental evidence for mTERT as a novel and unique marker of adult neural stem cells (ANSCs). We use a triple transgenic mouse line that is designed so that mTERT-positive cells will glow green, via Green Fluorescent Protein (GFP), when the animal ingests doxycycline. This inducible model allows mTERT positive cells to be tracked and identified easily. Dissociated brain tissues were taken from these animals and sorted via a Fluorescence-Activated Cell Sorter into GFP-positive and GFP-negative cells. GFP+ cells were shown to exhibit similar gene expression patterns to that of ANSCs. For further support, the triple transgenic animals were exposed to known neurogenic stimuli, namely exercise and fasting. The brains of these animals were eventually removed, sliced, immuno-stained and imaged using a fluorescent microscope. Imaging allowed us to identify mTERT+ cells in the choroid plexus, but not in the hippocampus, a classic neurogenic niche

Seasonal Patterns of Microhabitat Selection by a Sub-tropical Whip Spider, Phrynus longipes, in the Luquillo Experimental Forest, Puerto Rico

Phrynus longipes (Pocock 1894) is a top predator among arboreal invertebrates in the Luquillo Mountains of Puerto Rico, but many aspects of its ecology remain poorly understood. We sampled four of the most abundant tree species in the Luquillo Mountains during the dry and wet seasons of 2008 to evaluate microhabitat preferences of this species. In the dry season, P. longipes occurred significantly less frequently on a palm, Prestoea acuminata var. montana (Arecaceae), than the other tree species. Carapace length and the diameter of the tree on which an individual was found were positively correlated, suggesting competition for substrates. Microhabitat selection shifted in the wet season. Individuals occurred as frequently on P. acuminata as on any other species. The seasonal shift in substrate use could result from altered distribution or abundance of prey, an ontogenetic shift in substrate preference or greater competition arising from an increased abundance of P. longipes

Plant Distribution Data Show Broader Climatic Limits than Expert-Based Climatic Tolerance Estimates

Background Although increasingly sophisticated environmental measures are being applied to species distributions models, the focus remains on using climatic data to provide estimates of habitat suitability. Climatic tolerance estimates based on expert knowledge are available for a wide range of plants via the USDA PLANTS database. We aim to test how climatic tolerance inferred from plant distribution records relates to tolerance estimated by experts. Further, we use this information to identify circumstances when species distributions are more likely to approximate climatic tolerance. Methods We compiled expert knowledge estimates of minimum and maximum precipitation and minimum temperature tolerance for over 1800 conservation plant species from the ‘plant characteristics’ information in the USDA PLANTS database. We derived climatic tolerance from distribution data downloaded from the Global Biodiversity and Information Facility (GBIF) and corresponding climate from WorldClim. We compared expert-derived climatic tolerance to empirical estimates to find the difference between their inferred climate niches (ΔCN), and tested whether ΔCN was influenced by growth form or range size. Results Climate niches calculated from distribution data were significantly broader than expert-based tolerance estimates (Mann-Whitney p values \u3c\u3c 0.001). The average plant could tolerate 24 mm lower minimum precipitation, 14 mm higher maximum precipitation, and 7° C lower minimum temperatures based on distribution data relative to expert-based tolerance estimates. Species with larger ranges had greater ΔCN for minimum precipitation and minimum temperature. For maximum precipitation and minimum temperature, forbs and grasses tended to have larger ΔCN while grasses and trees had larger ΔCN for minimum precipitation. Conclusion Our results show that distribution data are consistently broader than USDA PLANTS experts’ knowledge and likely provide more robust estimates of climatic tolerance, especially for widespread forbs and grasses. These findings suggest that widely available expert-based climatic tolerance estimates underrepresent species’ fundamental niche and likely fail to capture the realized niche

Anti-Psychiatry And The Biomedical Model: From Delusion To Disorder

Psychiatry as it functions today is largely guided by the biomedical model of mental illness, which rests upon the notion that deviations in mental functioning are biological in nature. This thesis seeks to critique this understanding of psychological distress through the lens of the philosophical tradition of anti-psychiatry, drawing primarily from the works of Thomas Szasz and Michel Foucault. Szasz places emphasis on the diagnostic disparities between physiological and psychological illness, arguing that the experiences and behaviors that psychiatrists class as mental diseases are actually communicative strategies utilized by individuals who lack the tools to properly address the stressors in their lives. In contrast, Foucault approaches the issue from a historico-political context, considering the power dynamics involved in the psychiatric encounter by giving an account of its evolution since the days of the asylum. Drawing from the description of the biomedical model given by investigative journalist Robert Whitaker, I will consider how the philosophies of Szasz and Foucault relate to the modern psychiatric climate. Ultimately, I will argue that it is Foucault’s perspective that best equips us to critique the biomedical model, as its origins are inevitably intertwined with economic and political power

MRE11 facilitates the removal of human topoisomerase II complexes from genomic DNA

Topoisomerase II creates a double-strand break intermediate with topoisomerase covalently coupled to the DNA via a 5'-phosphotyrosyl bond. These intermediate complexes can become cytotoxic protein-DNA adducts and DSB repair at these lesions requires removal of topoisomerase II. To analyse removal of topoisomerase II from genomic DNA we adapted the trapped in agarose DNA immunostaining assay. Recombinant MRE11 from 2 sources removed topoisomerase IIalpha from genomic DNA in vitro, as did MRE11 immunoprecipitates isolated from A-TLD or K562 cells. Basal topoisomerase II complex levels were very high in A-TLD cells lacking full-length wild type MRE11, suggesting that MRE11 facilitates the processing of topoisomerase complexes that arise as part of normal cellular metabolism. In K562 cells inhibition of MRE11, PARP or replication increased topoisomerase IIalpha and beta complex levels formed in the absence of an anti-topoisomerase II dru

Hacking for Good - Workshop Summary

At the 2019 Charleston Library Conference, five facilitators from a diversity of organizations led a pre-conference called Hacking for Good. The goal of the half-day pre-conference was to introduce participants to the “hacking mindset” beyond the traditionally understood technology-driven terminology. In this context, hacking refersred to an approach of identifying a challenge or set of challenges in their respective knowledge organizations and gathering a set of techniques or approaches to address and overcome those challenges. The pre-conference provided a highly interactive and supportive environment to consider all aspects of a workplace challenge related to workflows and personnel and determine the most effective tools to tackle that challenge

Genetic analysis of hybridization and introgression between wild mongoose and brown lemurs.

BACKGROUND: Hybrid zones generally represent areas of secondary contact after speciation. The nature of the interaction between genes of individuals in a hybrid zone is of interest in the study of evolutionary processes. In this study, data from nuclear microsatellites and mitochondrial DNA sequences were used to genetically characterize hybridization between wild mongoose lemurs (Eulemur mongoz) and brown lemurs (E. fulvus) at Anjamena in west Madagascar. RESULTS: Two segments of mtDNA have been sequenced and 12 microsatellite loci screened in 162 brown lemurs and mongoose lemurs. Among the mongoose lemur population at Anjamena, we identified two F1 hybrids (one also having the mtDNA haplotype of E. fulvus) and six other individuals with putative introgressed alleles in their genotype. Principal component analysis groups both hybrids as intermediate between E. mongoz and E. fulvus and admixture analyses revealed an admixed genotype for both animals. Paternity testing proved one F1 hybrid to be fertile. Of the eight brown lemurs genotyped, all have either putative introgressed microsatellite alleles and/or the mtDNA haplotype of E. mongoz. CONCLUSION: Introgression is bidirectional for the two species, with an indication that it is more frequent in brown lemurs than in mongoose lemurs. We conclude that this hybridization occurs because mongoose lemurs have expanded their range relatively recently. Introgressive hybridization may play an important role in the unique lemur radiation, as has already been shown in other rapidly evolving animals.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are