Lepidophyma gaigeae

Number of Pages: 4Integrative BiologyGeological Science

Leptodactylus bufonius

Number of Pages: 22Integrative BiologyGeological Science

Ecological Consequences of Landscape Fragmentation on the Lizard Community in the Mescalero-Monahans Shinnery Sands

Landscape fragmentation poses a major threat to biodiversity world-wide. The goal of my dissertation research was to determine the effects of landscape fragmentation on a lizard community in the Mescalero-Monahans shinnery sands, New Mexico and the extent to which conservation efforts might protect biodiversity in this ecosystem. My research relied heavily on data collected from a large-scale spatially-replicated comparative study. The purpose of this study was to evaluate the impacts of landscape fragmentation as a result of oil and gas development on the dunes sagebrush lizard (Sceloporus arenicolus). Results from analysis of lizard community structure indicate that fragmented sites are less diverse than non-fragmented sites. In particular, two species are found in lower density and occupancy in the fragmented locations (Holbrookia maculata and Sceloporus arenicolus). Analysis of landscape configuration at the scale of a trapping grid indicated that sand dune blowout shape and size differed between fragmented and non-fragmented locations. Differences in landscape pattern were associated with reduced lizard diversity. Because of this association between lower diversity and altered landscape pattern, extensive alterations to landscape pattern may cause disassembly at the ecosystem level. The maintenance of existing landscape pattern may be important to the maintenance of diversity in this ecosystem. Evaluations of habitat use patterns of the lizards in this community demonstrate that a few species have narrow preferences for certain habitats. In particular, H. maculata, Phrynosoma cornutum, and S. arenicolus all demonstrated narrow habitat use patterns. Effect size of fragmentation for each species indicated that the same three species showed a large effect when comparing their average abundances between fragmented and non-fragmented locations. Thus species that are most likely to benefit or be harmed by landscape fragmentation are those with the most specific habitat requirements. Umbrella species represent one of many approaches to conservation using surrogate species. I used data on ants, beetles, small mammals, lizards, and endemic species to test the use of the dunes sagebrush lizard (Sceloporus arenicolus) as an umbrella for endemism and biodiversity of the Mescalero-Monahans shinnery sands ecosystem. I applied a comparative approach at three spatial scales to examine how conservation practices at different scales may affect biodiversity and endemism in this ecosystem. At the largest scale, the frequency of occurrence for endemic species increased though no other patterns emerged because S. arenicolus was present at all sites and there were no relationships between relative abundances of S. arenicolus and the other taxonomic groups. At the smallest scale, both beetle species richness, diversity, and endemic species richness were higher in the presence of S. arenicolus. To protect biodiversity in this ecosystem, conservation efforts should focus on protection at the scale of the species distribution rather than on the small-scale placement of individual well pads

Toward a Millimeter-Scale Tendon-Driven Continuum Wrist with Integrated Gripper for Microsurgical Applications

Microsurgery is a particularly impactful yet challenging form of surgery. Robot assisted microsurgery has the potential to improve surgical dexterity and enable precise operation on such small scales in ways not previously possible. Intraocular microsurgery is a particularly challenging domain in part due to the lack of dexterity that is achievable with rigid instruments inserted through the eye. In this work, we present a new design for a millimeter-scale, dexterous wrist intended for microsurgery applications. The wrist is created via a state-of-the-art two-photon-polymerization (2PP) microfabrication technique, enabling the wrist to be constructed of flexible material with complex internal geometries and critical features at the micron-scale. The wrist features a square cross section with side length of 1.25 mm and total length of 3.75 mm. The wrist has three tendons routed down its length which, when actuated by small-scale linear actuators, enable bending in any plane. We present an integrated gripper actuated by a fourth tendon routed down the center of the robot. We evaluate the wrist and gripper by characterizing its bend-angle. We achieve more than 90 degrees bending in both axes. We demonstrate out of plane bending as well as the robot's ability to grip while actuated. Our integrated gripper/tendon-driven continuum robot design and meso-scale assembly techniques have the potential to enable small-scale wrists with more dexterity than has been previously demonstrated. Such a wrist could improve surgeon capabilities during teleoperation with the potential to improve patient outcomes in a variety of surgical applications, including intraocular surgery.Comment: 2 pages, 3 figures, submitted to the 2023 Hamlyn Symposium on Medical Robotics conferenc

Impacts of forestry planting on primary production in upland lakes from north-west Ireland

Planted forests are increasing in many upland regions world-wide, but knowledge about their potential effects on algal communities of catchment lakes is relatively unknown. Here the effects of afforestation were investigated using palaeolimnology at six upland lake sites in the north-west of Ireland subject to different extents of forest plantation cover (4-64% of catchment area). 210Pb dated sediment cores were analysed for carotenoid pigments from algae, stable isotopes of bulk carbon (δ13C) and nitrogen (δ15N), and C/N ratios. In lakes with >50% of their catchment area covered by plantations, there were two- to six-fold increases in pigments from cryptophytes (alloxanthin) and significant but lower increases (39-116%) in those from colonial cyanobacteria (canthaxanthin), but no response from biomarkers of total algal abundance (β-carotene). In contrast, lakes in catchments with <20% afforestation exhibited no consistent response to forestry practices, although all lakes exhibited fluctuations in pigments and geochemical variables due to peat cutting and upland grazing prior to forest plantation. Taken together, patterns suggest that increases in cyanobacteria and cryptophyte abundance reflect a combination of mineral and nutrient enrichment associated with forest fertilisation and organic matter influx which may have facilitated growth of mixotrophic taxa. This study demonstrates that planted forests can alter the abundance and community structure of algae in upland humic lakes of Ireland and Northern Ireland, despite long histories of prior catchment disturbance

Functionally Distinct Subsets of Lineage-Biased Multipotent Progenitors Control Blood Production in Normal and Regenerative Conditions.

Despite great advances in understanding the mechanisms underlying blood production, lineage specification at the level of multipotent progenitors (MPPs) remains poorly understood. Here, we show that MPP2 and MPP3 are distinct myeloid-biased MPP subsets that work together with lymphoid-primed MPP4 cells to control blood production. We find that all MPPs are produced in parallel by hematopoietic stem cells (HSCs), but with different kinetics and at variable levels depending on hematopoietic demands. We also show that the normally rare myeloid-biased MPPs are transiently overproduced by HSCs in regenerating conditions, hence supporting myeloid amplification to rebuild the hematopoietic system. This shift is accompanied by a reduction in self-renewal activity in regenerating HSCs and reprogramming of MPP4 fate toward the myeloid lineage. Our results support a dynamic model of blood development in which HSCs convey lineage specification through independent production of distinct lineage-biased MPP subsets that, in turn, support lineage expansion and differentiation.This work was supported by NIH awards F32HL106989 and K01DK098315 to E.M.P, grants from Leukaemia and Lymphoma Research, Cancer Research UK and core support by the Wellcome Trust to B.G.; and NIH grant R01HL092471, Rita Allen Scholar Award and Leukemia Lymphoma Society Scholar Award to E.P.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Elsevier/Cell Press

Multiyear monitoring (2007-2013) of flat-tailed horned lizards (Phrynosoma mcallii)

Monitoring programs for species of conservation concern are notoriously flawed. Notably, many monitoring programs do not establish trigger points or a level of decline in population size that will result in management action. Here we report on the monitoring program for the Flat-tailed Horned Lizard (Phrynosoma mcallii) that has been established across its range throughout the United States by the Flat-tailed Horned Lizard Interagency Coordinating Committee (FTHL ICC). Impor- tantly, we examine whether a trigger point of 30% decline was detected in these populations. Between 2007 and 2013, we detected 955 P. mcallii on 2,714 occupancy surveys and captured 715 individuals on 1,861 demographic surveys. Occupancy surveys have demonstrated that the species occurs through- out the management areas and occupancy estimates range from 0.25–0.89. Demographic surveys have demonstrated that population trends over time are correlated across all management areas; however, they are probably driven by factors at smaller geographic scales. During the study no population decline \u3e 30% was detected after accounting for natural and stochastic fluctuations. Continued mon- itoring is called for to gain a greater understanding of what is driving the trends in populations both range-wide and at the scale of management areas

Is Mitigation Translocation an Effective Strategy for Conserving Common Chuckwallas?

Mitigation translocation remains a popular conservation tool despite ongoing debate regarding its utility for population conservation. To add to the understanding of the effectiveness of mitigation translocation, in 2017 and 2018 we monitored a population of protected common chuckwallas (Sauromalus ater) following translocation away from the area of construction of a new highway near the South Mountains, Phoenix, Arizona, USA. We removed chuckwallas from the construction right-of-way, paint-marked and pit-tagged them, and then released them in a nearby municipal preserve. We deployed very high frequency radio-telemetry transmitters on a sub-sample of 15 translocated adult chuckwallas. We monitored the radio-marked chuckwallas once a day at 1- to 3-day intervals for up to 46 days to document survival, body mass, and post-release movements. The average distance moved following translocation was 359 ± 53 m. Using minimum convex polygons, the average home range size of translocated lizards was 0.9 ± 0.3 ha, which was 18–45 times larger than expected for the species. Following translocations, we surveyed the translocation sites 1 month later and again 1 year later to determine the presence of translocated chuckwallas. Translocated individuals were rarely observed a second time: in 2017, only 11 of 160 translocated chuckwallas were seen again, and in 2018, only 11 of 192 translocated chuckwallas were detected. In the light of low recapture rate, consistent loss of body mass, and large movements of marked lizards, we conclude that survival of translocated chuckwallas was low over a single year. In the future, efficacy of mitigation translocation could be better evaluated by assessing the spatial ecology of both resident and translocated individuals simultaneously using radio-telemetry

Impacts of forestry planting on primary production in upland lakes from north-west Ireland

Planted forests are increasing in many upland regions worldwide, but knowledge about their potential effects on algal communities of catchment lakes is relatively unknown. Here, the effects of afforestation were investigated using palaeolimnology at six upland lake sites in the north-west of Ireland subject to different extents of forest plantation cover (4–64% of catchment area). 210Pb-dated sediment cores were analysed for carotenoid pigments from algae, stable isotopes of bulk carbon (δ13C) and nitrogen (δ15N), and C/N ratios. In lakes with >50% of their catchment area covered by plantations, there were two- to sixfold increases in pigments from cryptophytes (alloxanthin) and significant but lower increases (39–116%) in those from colonial cyanobacteria (canthaxanthin), but no response from biomarkers of total algal abundance (β-carotene). In contrast, lakes in catchments with <20% afforestation exhibited no consistent response to forestry practices, although all lakes exhibited fluctuations in pigments and geochemical variables due to peat cutting and upland grazing prior to forest plantation. Taken together, patterns suggest that increases in cyanobacteria and cryptophyte abundance reflect a combination of mineral and nutrient enrichment associated with forest fertilization and organic matter influx which may have facilitated growth of mixotrophic taxa. This study demonstrates that planted forests can alter the abundance and community structure of algae in upland humic lakes of Ireland and Northern Ireland, despite long histories of prior catchment disturbance