Biology subjects

Campbell, C. J.

Publications and source records attributed to Campbell, C. J..

6 recordsLinked to original sources

bioRxiv2026

Water plant functional groups: a trait-based classification database for Australian plants

Trait-based functional classifications of species offer improved generality in predicting responses to environmental conditions. Water plant functional groups (WPFG) are one such classification. Grouping plant species based on traits associated with germination, growth and reproductive requirements, WPFG have proven useful in examining plant trait-hydrological relationships in aquatic plant research in Australia. Here, we collate existing information from across academic, government and personal databases to create the most comprehensive compilation of plant taxa assignments to WPFG available. Taxonomic nomenclature was first standardized using accepted names under the Australian Plant Census/Australian Plant Name Index. We then assessed agreement among source classifications and derived a consensus-weighted fuzzy classification that retains uncertainty in WPFG assignment at both the species- and genus-level. The resulting database provides evidence-based classifications for the most commonly observed water plants in temperate Australia, including evidence of affinity to all functional groups. This approach supports greater consistency, transparency and reproducibility in WPFG assignment across studies while allowing users to select the level of classification most appropriate to their application. The database is freely available for download from the Zenodo digital repository.

ecology↗

bioRxiv2024

Precipitation tolerance determines elevational migration strategies of resident birds of the Western Ghats of India.

O_LIAvian elevational migration is a common but often overlooked form of short-distance migration. Numerous hypotheses have been proposed to explain this behavior, yet few studies have tested those comprehensively. We examine the climatic constraint hypothesis - a key hypothesis explaining elevational migration - to evaluate its predictions for avian elevational migration in the monsoon-dominated Western Ghats of India. C_LIO_LIWe used citizen science data from eBird to quantify elevational migration patterns of resident birds of the region. Using robust data curation protocols and new bias correction methods, we modeled migration patterns of 164 species across summer, monsoon and winter seasons. To formally test the climatic constraint hypothesis, we modeled the likelihood and distance of migration against body size and environmental niche breadths, using phylogenetically informed logistic regression and Bayesian generalized linear mixed models. C_LIO_LIOur results show that 43% of resident birds exhibited elevational migration in at least one season. Most species migrated between winter and summer (57), followed by migrations between summer and monsoon (39) and then monsoon and winter (38). Species predominantly moved upslope in summer (82%) and downslope in monsoon (87%), with no discernible pattern of direction in winter. Species with broader temperature tolerances were more likely to migrate across all seasons. Additionally, species with broader precipitation niches and larger body sizes moved further downslope during the monsoon and winter, respectively. C_LIO_LIWe found that species with broader tolerances to environmental conditions were more likely to be migratory and moved further along the elevational gradient, contradictory to the expectations of the climatic constraint hypothesis. Our analyses suggest that elevational migrants of the Western Ghats are not climatically limited but likely possess flexibility to track ecological resources that vary with season and elevation. C_LI

ecology↗

bioRxiv2024

Macroevolutionary Constraint and Selection on Anti-Bat Moth Tails

Elaborate traits evolve via intense selective pressure, overpowering ecological constraints. Hindwing tails that thwart bat attack have repeatedly originated in moon moths (Saturniidae), with longer tails having greater anti-predator effect. Here, we take a macroevolutionary approach to evaluate the evolutionary balance between predation pressure and possible limiting environmental factors on tail elongation. To trace the evolution of tail length across time and space, we inferred a time-calibrated phylogeny of the entirely tailed moth group (Actias + Argema) and performed ancestral state reconstruction and biogeographical analyses. We generated metrics of predation via estimates of bat abundance from nearly 200 custom-built species distribution models and environmental metrics via estimates of bioclimatic variables associated with individual moth observations. To access community science data, we developed a novel method for measuring wing lengths from un-scaled photos. Integrating these data into phylogenetically-informed mixed models, we find a positive association between bat predation pressure and moth tail length and body size, and a negative association between environmental factors and these morphological traits. Regions with more insectivorous bats and more consistent temperatures tend to host longer-tailed moths. Our study provides insight into tradeoffs between biotic selective pressures and abiotic constraints that shape elaborate traits across the tree-of-life.

evolutionary biology↗

bioRxiv2024

Unusual migratory strategy a key factor driving interactions at wind energy facilities in at-risk bats

Seasonal movement strategies are poorly understood for most animals, impeding broader understanding of processes underlying migration and limiting practical conservation needs. Here we develop and implement a framework for integrating multiple sources of endogenous markers, in particular stable hydrogen isotope data, that capture and scale dynamics from the movements of individuals to that of continental migration. We assembled and integrated thousands of new isotopic measurements from bat fur with existing datasets and applied this framework to reveal migratory patterns of three broadly distributed bat species most at risk for fatalities at wind energy facilities. Our findings show that the species comprising the lowest proportion of wind turbine fatalities (silver-haired bats) exhibits expected movements to lower latitudes in autumn and higher latitudes in spring. Surprisingly, the two species with higher wind turbine fatality rates (hoary and eastern red bats) have more complex movements, including significant movement to higher latitudes during autumn. We term this unique strategy "pell-mell" migration, during which some individuals are as likely to move to higher latitudes as lower latitudes, relative to their individual summering grounds, in early autumn, after which they move to similar or lower latitudes to overwinter. The pell-mell migratory period corresponds with peak fatalities at wind energy facilities, and bats moving northward during autumn are associated with mortality at those facilities. Our results provide direct support for the hypothesis that bat fatalities at wind energy facilities are related to migration and highlight the importance of migratory distance as an ultimate driver of increased interactions with wind energy facilities, which appears significantly greater for species that travel widely across latitudes in the autumn.

ecology↗

bioRxiv2023

YlaN is an iron(II) binding protein that functions to relieve Fur-mediated repression of gene expression in Staphylococcus aureus

Iron (Fe) is a trace nutrient required by nearly all organisms. As a result of the demand for Fe and the toxicity of non-chelated cytosolic ionic Fe, regulatory systems have evolved to tightly balance Fe acquisition and usage while limiting overload. In most bacteria, including the mammalian pathogen Staphylococcus aureus, the ferric uptake regulator (Fur) is the primary transcriptional regulator that controls the transcription of genes that code for Fe uptake and utilization proteins. YlaN was demonstrated to be essential in Bacillus subtilis unless excess Fe is added to the growth medium, suggesting a role in Fe homeostasis. Here, we demonstrate that YlaN is expendable in S. aureus; however, YlaN became essential upon Fe deprivation. A null fur allele bypassed the essentiality of YlaN. The transcriptional response of Fur derepression resulted in a reprogramming of metabolism to prioritize fermentative growth over respiratory growth. The absence of YlaN diminished the derepression of Fur-dependent transcription during Fe limitation. Bioinformatic analyses suggest that ylaN was recruited to Gram positive bacteria and once acquired was maintained in the genome as it co-evolved with Fur. Consistent with a role for YlaN in influencing Fur-dependent regulation, YlaN and Fur interacted in vivo. YlaN bound Fe(II) in vitro using oxygen or nitrogen ligands with an association constant that is consistent with a physiological role in Fe sensing and/or buffering. These findings have led to a model wherein YlaN is an Fe(II) binding protein that influences Fur-dependent regulation through direct interaction. ImportanceIron (Fe) is an essential nutrient for nearly all organisms. If Fe homeostasis is not maintained, Fe can accumulate in the cytosol where it is toxic. Questions remain about how cells efficiently balance Fe uptake and usage to prevent imbalance. Iron uptake and proper metalation of proteins are essential processes in the mammalian bacterial pathogen Staphylococcus aureus. Understanding the gene products involved in Fe ion regulation, uptake, and usage, as well as the physiological adaptations that S. aureus uses to survive in Fe-depleted conditions, will provide insight into the role that Fe has in pathogenesis. These data will also provide insight into the selective pressures imparted by the mammalian host.

microbiology↗

bioRxiv2018

Checkpoint non-fidelity induces a complex landscape of lineage fitness after DNA damage

DNA damage in proliferating mammalian cells causes death1, senescence2 or continued survival, via checkpoints that monitor damage and regulate cell cycle progression, DNA repair and fate determination3. Cell cycle checkpoints facilitate tumour suppression by preventing the generation of proliferating mutated cells4, particularly by blocking passage of DNA lesions into replication and mitosis5. While checkpoint non-fidelity permits cells to carry genomic aberrations into subsequent cell cycle phases6, its long-term consequences on lineages descendant from damaged cells remains poorly characterised. Devising methods for microscopy-based lineage tracing, we unexpectedly demonstrate that transient DNA damage to single living cells bearing a negligent checkpoint induces heterogenous cell-fate outcomes in their descendant generations removed from the initial insult. After transiently damaged cells undergo an initial arrest, pairs of descendant cells without obvious cell-cycle abnormalities either divide or die in a seemingly stochastic way. Progeny of transiently damaged cells may die generations afterwards, creating considerable variability of lineage fitness that promotes overall persistence in a mutagenic environment. Descendants of damaged cells frequently form micronuclei, activating immunogenic signalling. Our findings reveal previously unrecognized, heterogenous effects of cellular DNA damage that manifest long afterwards in descendant cells. We suggest that these heterogenous descendant cell-fate responses may function physiologically to ensure the elimination and immune clearance of damaged cell lineages, but pathologically, may enable the prolonged survival of cells bearing mutagenic damage.

cancer biology↗