Herpetofauna responses to agricultural matrix management

Preventing biodiversity loss in fragmented agricultural landscapes is a global problem that requires knowledge of how species move through landscapes. Farming practices can increase the contrast between remnant patches of native vegetation and adjoining habitats, with negative consequences for species movement and the preservation of biodiversity. Yet, the relationships between habitat attributes and the presence of species are poorly understood, and the mechanisms influencing cross-habitat movement has rarely been empirically tested, particularly for less mobile organisms such as frogs, snakes and lizards (herpetofauna). To address this important knowledge gap, I used a large-scale, empirical experiment to examine herpetofauna abundance, species richness, body condition, risk of predation, and inter-habitat movement between remnant woodland patches, edges and four contrasting farm land use types: 1) crop fields, 2) pasture paddocks, 3) linear plantings, and 4) woody mulch applied to a crop paddock after harvest. I also examined the effect of crop harvesting and seasonal effects on the distribution and abundance of herpetofauna. In the second and third chapters of the thesis, I compared the habitat preferences and abundance and, richness and body condition (frogs only) of reptiles and frogs to predictions developed from a conceptual matrix model and literature review. I found the structure and quality of the matrix was a stronger influence on reptile abundance, species richness and movement than the temporal effect of crop harvesting (chapter 2). My results demonstrate remnant patches and farmland, particularly those with woody vegetation plantings, can provide suitable habitat for common reptile species, but this environment is not readily interchangeable as habitat for uncommon reptile species. The negative response of uncommon reptile abundance and species richness to farmland, irrespective of restoration, indicate that farmland not only reduced their abundance but also the likelihood of presence. I also observed a negative trend in uncommon reptile abundance in remnant patches adjacent to crop paddocks. These findings suggest that crop paddocks and associated farming activities may be negatively influencing animals within both patches and matrix, further isolating populations, and reinforcing the negative consequences of conversion to agriculture for reptile populations. In Chapter three, my study revealed while frog abundance was positively associated with woody vegetation plantings within farmland, many frog species were found ubiquitously throughout the landscape, reflecting the dominance of a few disturbance tolerant species in the amphibian assemblage. My movement data demonstrated that frogs used multiple farmland types, moved between remnant patches and farmland, and into and out of cropped paddocks across harvesting periods. Unexpectedly, I found crop harvesting did not reduce frog abundance in crop paddocks, with some individuals persisting in farmland after harvesting. Body condition analyses indicated that farmland areas may provide good quality habitat for frogs and allow movement, dispersal, and foraging opportunities. My findings provide important insights into the utilisation of highly modified farmland as terrestrial habitat for frogs. This new knowledge is valuable in the context of land use intensification, and global amphibian declines. While much effort has focused on the protection of aquatic habitats for amphibians, management strategies must also consider the range of contrasting farmland types present in cropping areas, and the habitat requirements of the target species. In the fourth chapter, I explored how contrasting habitats and farm management influences predation risk in lizards using wildlife cameras and plasticine replica lizard models. I found predation pressure from multiple predators, operating across the landscape, could be compounding the effects of habitat degradation and fragmentation. Predation attempts on models were highest at habitat edges, with a reduced risk within farmland and remnant patches. My findings suggest edge habitats are ‘risker’ for lizards than farmland, and may act as a population sink, preventing reptiles from moving into the farmland if individuals suffer increased mortality at the edge. Such trends have not been previously reported for cropped landscapes. Finally, in the fifth chapter, I examined detailed movement patterns and behavior of a patch-dependent gecko species, Eastern Tree Dtella Gehyra versicolor, using radio-telemetry, fluorescent powder and an experiment displacement to examine movement and avoidance behaviour in response to different woodland to farmland edges. Unexpectedly, I found edge effects with a strong partitioning of individuals away from farmland, irrespective of the presence of complex habitat (e.g. linear plantings), in preference for remnant patches. We found pasture environments promoted direct movements of displaced geckos at a set distance from remnant patches into pastures. However, none of the radio-tracked geckos crossed the woodland-pasture edge, suggesting pastures may reduce homing ability of geckos. These findings contrast with the known ecology of the species and suggest, despite efforts to improve farmland quality by planting, farmland is not a preferred habitat for this species and does not promote longer distance dispersal movements. By examining the influence of anthropogenic habitat change on herpetofauna it is possible to improve our understanding of the distribution of species outside of remnant native vegetation. My research findings provide new insights into the complex responses of herpetofauna to contrasting farmland uses in cropping landscapes. I provide evidence for potential drivers to explain herpetofauna distribution within highly disturbed areas. Importantly, I have demonstrated the relative value of different farmland types for facilitating and reducing movement and providing habitat across diverse agricultural landscapes. Through my series of inter-connected studies, I highlight important opportunities to promote herpetofauna conservation in agricultural landscapes by protecting remnant native vegetation and by increasing restoration efforts in cropping landscapes by establishing linear plantings. I also identify management practices to reduce mortality risk in areas where dispersal may be important by focusing on implementing strategies that increase shelter opportunities for lizards and to reduce the size of edges particularly where dispersal may be important (such as between remnants and linear plantings). This new knowledge is valuable in the context of promoting landscape connectivity, targeted restoration programs, and arresting global herpetofauna decline

Na(V)1.5 sodium channel window currents contribute to spontaneous firing in olfactory sensory neurons

Olfactory sensory neurons (OSNs) fire spontaneously as well as in response to odor; both forms of firing are physiologically important. We studied voltage-gated Na+ channels in OSNs to assess their role in spontaneous activity. Whole cell patch-clamp recordings from OSNs demonstrated both tetrodotoxin-sensitive and tetrodotoxin-resistant components of Na+ current. RT-PCR showed mRNAs for five of the nine different Na+ channel α-subunits in olfactory tissue; only one was tetrodotoxin resistant, the so-called cardiac subtype NaV1.5. Immunohistochemical analysis indicated that NaV1.5 is present in the apical knob of OSN dendrites but not in the axon. The NaV1.5 channels in OSNs exhibited two important features: 1) a half-inactivation potential near −100 mV, well below the resting potential, and 2) a window current centered near the resting potential. The negative half-inactivation potential renders most NaV1.5 channels in OSNs inactivated at the resting potential, while the window current indicates that the minor fraction of noninactivated NaV1.5 channels have a small probability of opening spontaneously at the resting potential. When the tetrodotoxin-sensitive Na+ channels were blocked by nanomolar tetrodotoxin at the resting potential, spontaneous firing was suppressed as expected. Furthermore, selectively blocking NaV1.5 channels with Zn2+ in the absence of tetrodotoxin also suppressed spontaneous firing, indicating that NaV1.5 channels are required for spontaneous activity despite resting inactivation. We propose that window currents produced by noninactivated NaV1.5 channels are one source of the generator potentials that trigger spontaneous firing, while the upstroke and propagation of action potentials in OSNs are borne by the tetrodotoxin-sensitive Na+ channel subtypes.This work was aided by support from Boston University, the Rocky Mountain Taste and Smell Center Core for Cellular Visualization and Analysis [National Institute on Deafness and Other Communication Disorders (NIDCD) P30 DC-04657; D. Restrepo, principal investigator], and NIDCD Grants DC-04863 to V. Dionne and DC-006070 to D. Restrepo and T. E. Finger. (Boston University; P30 DC-04657 - Rocky Mountain Taste and Smell Center Core for Cellular Visualization and Analysis [National Institute on Deafness and Other Communication Disorders (NIDCD)]; DC-04863 - Rocky Mountain Taste and Smell Center Core for Cellular Visualization and Analysis [National Institute on Deafness and Other Communication Disorders (NIDCD)]; DC-006070 - Rocky Mountain Taste and Smell Center Core for Cellular Visualization and Analysis [National Institute on Deafness and Other Communication Disorders (NIDCD)])https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4122723/Accepted manuscrip

Influence of transmission line construction on winter sage-grouse habitat use in southern Utah

The construction and operation of electric power transmission lines (“power lines”) and their associated infrastructure has been identified as a conservation threat to the greater sage-grouse (Centrocercus urophasianus; sage-grouse). The conservation buff er zones recommended by state and federal agencies to avoid potential impacts on breeding populations diff er because information regarding the effects of power lines on sage-grouse is lacking. Little information is available regarding sage-grouse responses to power lines placed in winter habitat. Hence, we evaluated sage-grouse habitat use before and after construction of the Sigurd-Red Butte (SRB) 345-kilovolt (kV) transmission line in winter habitat. The SRB line was constructed in the fall of 2014, and was sited parallel to a pre-existing 500-kV transmission line through salt-desert habitat on the western edge of what is now the Bald Hills Sage-Grouse Management Area (SGMA) in southern Utah. We deployed Global Positioning System (GPS) transmitters on 2 female and 16 male sage-grouse from 2014–2016 and compared collected locations to data independently acquired in the winter of 2011–2012 to determine if the construction of the SRB transmission line altered sage-grouse winter habitat use. Using the 2014–2016 data, we developed a resource selection function (RSF) model to quantify the influence of transmission line presence on sage-grouse movements while accounting for low quality habitat (salt-desert) near the transmission line. Post-construction data were compared to the 2011–2012 data to evaluate whether RSF-predicted changes in relative probability of use were reflected in actual shifts in habitat use before and after construction. The top RSF model contained a significant negative interaction between distance to transmission line and average salt-desert coverage within a 1-km2 moving window. Although a comparison of pre and post-construction mapped RSFs predicted a decreased probability of winter habitat use in the vicinity of the transmission line corridor as a result of the new line, we did not detect increased avoidance by sage-grouse when comparing spatial distributions between winters using minimum convex polygons. This suggests that immediate negative effects of new transmission line construction can be eliminated by implementing best management practices such as co-locating the transmission line in a preexisting energy corridor where impacts on habitat selection have already occurred, and siting the line in poor-quality habitat that does not fragment existing habitat. However, we caution that there may be other long-term influences of transmission line installation that are outside the scope of our 2-year post-construction study design, and more research is required to assess the influence of transmission lines on sagegrouse winter habitat use over longer timescales

Predation risk for reptiles is highest at remnant edges in agricultural landscapes

1. Preventing biodiversity loss in fragmented agricultural landscapes is a global problem. The persistence of biodiversity within remnant vegetation can be influenced by an animal’s ability to move through the farmland matrix between habitat patches. Yet, many of the mechanisms driving species occurrence within these landscapes are poorly understood, particularly for reptiles. 2. We used scented and unscented plasticine lizard models and wildlife cameras to (1) estimate predation risk of reptiles in four farmland types (crop field, pasture paddock, restoration tree planting and areas with applied woody mulch) relative to the patch edge and remnant vegetation, and (2) examine how predation risk was influenced by temporal change in the matrix (crop harvesting). 3. Birds (55.1%), mammals (41.1%), reptiles (3.4%) and invertebrates (0.5%) attacked models, of which 87% were native species. Mammalian predators were 60.2% more likely to attack scented models then unscented models. Bird predators were not influenced by scent. 4. We found predator attacks on models were highest at edges (49%, irrespective of adjacent farmland type, with a reduced risk within farmland (29%) and remnant patches (33%) (P<0.01). Both mammal and bird predators contributed to high numbers of predation attempts at edges. 5. Removal of crops did not increase predation attempts in crop fields or other farmland types, although predation attempts were significantly lower along the crop transect after harvesting, compared to the woody debris transect. However, numbers of predation attempts were higher in edge habitats, particularly prior to harvesting. 6. Synthesis and applications. Reptiles are at risk of predation by birds and mammals in both remnant patches and the farmland matrix, particularly in edge habitat. Our results demonstrate that edge habitats are potentially riskier for lizards than the farmland. Vulnerability to predation may be increased by a lack of shelter within edge habitats such as by increasing visibility of reptiles to predators. Therefore, to benefit reptiles, land managers could provide shelter (rocks, logs and grasses), particularly between remnants and linear plantings which could improve landscape connectivity.Funding was provided by the Central Tablelands Local Land Services, Lake Cowal Foundation, NSW Office of Environment and Heritage Environmental Trust and the Lake Cowal Foundation

Neutrino Mixing and Cosmology

We review the consequences of neutrino mixing in the early universe. For both active-sterile mixing or mixing between three active neutrinos only, the consequences of oscillations depend crucially upon the size of the universe's lepton number (relic neutrino asymmetry.)Comment: 3 pages, talk at TAUP 200

Amphibians in agricultural landscapes: the habitat value of crop areas, linear plantings and remnant woodland patches

Mitigating the negative impacts of agriculture on amphibians requires knowledge of how different land uses affect species distribution and community composition. In the case of frogs, there is currently insufficient information on their use of terrestrial habitats in cropping landscapes to inform conservation planning. We examined how four different farmland types (linear plantings, cereal crops, grazing paddocks and woody mulch) and crop harvesting influenced amphibian abundance, richness, body condition and movement. We found the abundance of frogs was significantly higher in linear plantings compared to grazing paddocks and adjacent patches of remnant woodland vegetation. However, species richness and abundance of three individual species did not vary significantly between farmland types. For the most common frog Uperoleia laevigata, body condition was higher at the edges of the woody debris treatment (coupled with higher abundance) and lower in farmland with debris and linear plantings. The body condition of Limnodynastes tasmaniensis and L. interioris was not influenced by farmland type. Frog abundance and condition was largely unaffected by crop harvesting. However, frogs were less common after harvesting at the edges of farmland and within remnant patches. Movement patterns did not suggest mass movement out of crops after harvest, where almost half of all individuals recaptured remained within the farmland. These results suggest that some generalist frog species may have an affinity for habitats within agricultural paddocks, particularly when key habitat features like plantings are present. However, we found overall frog richness was low and did not differ between remnant patches, edges and farmland which may be an indication of habitat degradation within terrestrial habitats across the landscape. Although protection of remnant native vegetation is important, conservation strategies for the protection of amphibians will be ineffective if they do not consider the variety of land uses and the relationships of different species and their microhabitats within and outside of patches.Funding was provided by the Australian Government Research Training Program, Central Tablelands Local Land Services, NSW Environmental Trust and the Lake Cowal Foundation

A Mixed‑Methods Exploration of the Developmental Trajectory of Autonomous Motivation in Graduate Medical Learners

Self-determination theory (SDT), when applied to curricular construction, emphasizes curiosity, self-awareness, and resilience. Physicians need these qualities to face the challenges of clinical practice. SDT offers a lens for medical educators to track learner development toward sustainable, rewarding careers. This study describes the changes observed in learner communications about feelings of competence, relatedness, and autonomy across a 3-year family medicine training program designed to develop activated, lifelong learners

Specificity of Anti-Citrullinated Protein Antibodies to Citrullinated &#945;-Enolase Peptides as a Function of Epitope Structure and Composition

Rheumatoid arthritis (RA) is an autoimmune disease affecting approximately 1–2% of the world population. In addition to the first discovered serologic markers for RA, the rheumatoid factors (RFs), anti-citrullinated protein antibodies (ACPAs) are even more specific for the disease compared to RFs and are found in 70–80% of RA patient sera. RA etiopathogenesis still needs to be elucidated, as different factors are proposed to be involved, such as Epstein–Barr virus infection. Hence, understanding the interaction between ACPAs and their citrullinated peptide targets is relevant for a better knowledge of RA pathophysiology and for diagnostic purposes. In this study, a cohort of RA sera, healthy control sera and multiple sclerosis sera were screened for reactivity to a variety of citrullinated peptides originating from α-enolase, pro-filaggrin, proteoglycan and Epstein–Barr nuclear antigen-2 by enzyme-linked immunosorbent assay. ACPA reactivity to citrullinated α-enolase peptides was found to depend on peptide length and peptide conformation, favouring cyclic (disulfide bond) conformations for long peptides and linear peptides for truncated ones. Additional investigations about the optimal peptide conformation for ACPA detection, employing pro-filaggrin and EBNA-2 peptides, confirmed these findings, indicating a positive effect of cyclization of longer peptides of approximately 20 amino acids. Moreover, screening of the citrullinated peptides confirmed that ACPAs can be divided into two groups based on their reactivity. Approximately 90% of RA sera recognize several peptide targets, being defined as cross-reactive or overlapping reactivities, and whose reactivity to the citrullinated peptide is considered primarily to be backbone-dependent. In contrast, approximately 10% recognize a single target and are defined as nonoverlapping, primarily depending on the specific amino acid side-chains in the epitope for a stable interaction. Collectively, this study contributed to characterize epitope composition and structure for optimal ACPA reactivity and to obtain further knowledge about the cross-reactive nature of ACPAs

Heat Shock Protein 70 Promotes Cell Survival by Inhibiting Lysosomal Membrane Permeabilization

Heat shock protein 70 (Hsp70) is a potent survival protein whose depletion triggers massive caspase-independent tumor cell death. Here, we show that Hsp70 exerts its prosurvival function by inhibiting lysosomal membrane permeabilization. The cell death induced by Hsp70 depletion was preceded by the release of lysosomal enzymes into the cytosol and inhibited by pharmacological inhibitors of lysosomal cysteine proteases. Accordingly, the Hsp70-mediated protection against various death stimuli in Hsp70-expressing human tumor cells as well as in immortalized Hsp70 transgenic murine fibroblasts occurred at the level of the lysosomal permeabilization. On the contrary, Hsp70 failed to inhibit the cytochrome c–induced, apoptosome-dependent caspase activation in vitro and Fas ligand–induced, caspase-dependent apoptosis in immortalized fibroblasts. Immunoelectron microscopy revealed that endosomal and lysosomal membranes of tumor cells contained Hsp70. Permeabilization of purified endo/lysosomes by digitonin failed to release Hsp70, suggesting that it is physically associated with the membranes. Finally, Hsp70 positive lysosomes displayed increased size and resistance against chemical and physical membrane destabilization. These data identify Hsp70 as the first survival protein that functions by inhibiting the death-associated permeabilization of lysosomes