Biology subjects

Hughes, M. M.

Publications and source records attributed to Hughes, M. M..

4 recordsLinked to original sources

bioRxiv2026

Ecosystem disservices are underrepresented in literature on annual crop agroecosystems

Maximising ecosystem service (ES) benefits while minimising ecosystem disservices (EDS) is essential for ecological intensification in annual crop systems. Yet ecosystem disservices are often underreported in the scientific literature, potentially biasing how agroecosystem functioning is understood. To test this, we built a predicted network of plausible links between ecosystem service providers (taxa or functional groups that can deliver ecosystem services or disservices), and the ES or EDS they may provide. We then compared this with a realised network based on systematic Scopus searches of annual crop literature. The predicted network contained 47 nodes and 103 links, whereas the realised network contained 33 nodes and 58 links, representing declines of 29.8% in nodes and 43.7% in links. Overall connectivity declined, especially for highly connected nodes, and four of the nine predicted disservice nodes were absent from the literature. ES links were more likely to be documented than EDS links, and EDS links were three times more likely to be absent. Across all links, ES were reported in 6.6 times more papers than EDS. Projected networks, which map indirect connections by linking ES directly to EDS if they share common providers, showed that these bundled interactions were strongly reduced, obscuring multifunctionality and trade-offs. This systematic underrepresentation of EDS, reflecting a cognitive bias, can inflate perceived benefits, distort the evaluation of key taxa and interactions, and create unrealistic expectations about intervention outcomes in biological crop protection. Addressing EDS alongside ES is therefore essential for more balanced assessments of crop-system management and better-informed decisions.

ecology↗

bioRxiv2026

Inbreeding and demographic history of caribou (Rangifer tarandus) in western Canada inferred from genome-wide SNP data

Assessing genetic diversity is essential for conserving endangered populations, yet comprehensive genomic evaluations remain limited for many declining species. Here, we investigated inbreeding levels and effective population sizes (Ne) of caribou (Rangifer tarandus) in western Canada, where populations have experienced pronounced declines over the past centuries due to anthropogenic pressures and climate change. We analyzed 33,346 Single Nucleotide Polymorphisms (SNPs) from 759 individuals representing 45 subpopulations within six metapopulations to: (1) assess inbreeding using runs of homozygosity (ROHs), (2) estimate contemporary and historical Ne, and (3) evaluate relationships between census size (Nc), inbreeding, and Ne. Small and endangered subpopulations, predominantly in southern regions, generally exhibited high inbreeding (FROH > 0.1), although some larger populations also showed elevated levels. Most subpopulations displayed a mixture of short and long ROHs, indicating both ancient shared ancestry and recent inbreeding. Twelve subpopulations had Ne <50, and 28 subpopulations and all metapopulations had Ne < 500, suggesting compromised short-term viability and long-term adaptive potential. Nc significantly predicted inbreeding (R{superscript 2} = 0.25), whereas contemporary Ne did not. Historical Ne reconstructions revealed a north-to-south gradient in bottleneck timing: northern populations declined in [~]1700-1780, central populations in [~]1780-1860, and southern populations in [~]1860-1940, likely driven by sequential impacts of climate shifts and anthropogenic disturbances. Our findings identify at-risk populations requiring urgent genetic intervention and demonstrate that integrating inbreeding and Ne estimates provides a robust framework for caribou recovery and the management of fragmented wildlife populations.

evolutionary biology↗

bioRxiv2025

Glacial history and landscape features shape the hierarchical population genetic structure of woodland caribou (Rangifer tarandus caribou) in western Canada

Caribou, listed as a species at risk across Canada, have experienced a wide range of evolutionary and selective pressures at multiple scales, from large-scale range shifts and recolonisations driven by glacial cycles to more localized contemporary habitat degradation and fragmentation. Given these multi-scale evolutionary forces, genetic variation and diversity are expected to be hierarchically structured. Characterising hierarchical population structure is crucial to understanding a species evolutionary history and informing effective conservation and management strategies. In this study, we analysed genomic diversity and variation in woodland caribou (Rangifer tarandus caribou) across western Canada using genotypes from [~]33,000 Single Nucleotide Polymorphism (SNP) loci from 759 geo-referenced individuals spanning 45 pre-defined subpopulations. We employed genetic clustering methods and measures of genetic differentiation to characterize hierarchical population structure in the region and tested for latitudinal changes in heterozygosity resulting from post-glacial recolonisation and hybridisation. Our results confirm that woodland caribou genetic diversity and differentiation occur at multiple hierarchical levels, reflecting post-glacial recolonisation patterns and landscape heterogeneity. Notably, the major genetic clusters identified in our study do not align with current conservation units for the species in this region. We also observe elevated heterozygosity in the mid-latitudes of the sampled range, indicative of hybridisation following secondary contact during post-glacial recolonisation. These findings underscore the need to consider and include genetic diversity at all hierarchical levels in conservation planning, as wide-ranging species often experience diverse and complex evolutionary histories and pressures.

evolutionary biology↗

bioRxiv2021

Astrocytic C-X-C motif chemokine ligand-1 mediates β-amyloid-induced tau mislocalization and synaptotoxicity

BackgroundPathological interactions between {beta}-amyloid (A{beta}) and tau drive the synapse loss that underlies neural circuit disruption and cognitive decline in Alzheimers disease (AD). Reactive astrocytes, displaying altered functions, are also a prominent feature of AD brain. This large and heterogeneous population of cells are increasingly recognised as contributing to early phases of disease. However, the contribution of astrocytes to detrimental A{beta}-tau interactions in AD is not well understood. MethodsMouse and human astrocyte cultures were stimulated with concentrations and species of human A{beta} that mimic those in human AD brain. Astrocyte conditioned medium was collected and immunodepleted of A{beta} before being added to rodent or human neuron cultures. Cytokines, identified in unbiased screens were also applied to neurons, including following the pre-treatment of neurons with chemokine receptor antagonists. Tau mislocalisation, synaptic markers and dendritic spine numbers were measured in cultured neurons and organotypic brain slice cultures. ResultsConditioned medium from astrocytes stimulated with A{beta} induces tau mislocalisation and exaggerated synaptotoxicity that is recapitulated following spiking of neuron culture medium with recombinant C-X-C motif chemokine ligand-1 (CXCL1), a chemokine we show to be upregulated in Alzheimers disease brain. Antagonism of neuronal C-X-C motif chemokine receptor 2 (CXCR2) prevented tau mislocalisation and synaptotoxicity in response to CXCL1 and A{beta}-stimulated astrocyte secretions. ConclusionsOur data indicate that astrocytes exacerbate tau mislocalisation and the synaptotoxic effects of A{beta} via interactions of astrocytic CXCL1 and neuronal CXCR2 receptors, highlighting this chemokine-receptor pair as a novel target for therapeutic intervention in AD.

neuroscience↗