Biology subjects

Griffin, J. N.

Publications and source records attributed to Griffin, J. N..

7 recordsLinked to original sources

bioRxiv2025

Integrating functional and phylogenetic perspectives reveals new priorities for bird and mammal conservation

Finite resources dictate that conservation biologists must prioritise some species over others. Conservation metrics, such as EDGE (Evolutionarily Distinct and Globally Endangered; EDGE1) and FUSE (Functionally Unique, Specialised and Endangered), make prioritisation based on species evolutionary or functional distinctiveness, respectively, and degree of threat. EDGE is in part based on the rationale that the evolutionary distinctiveness it captures serves to maximise biodiversity in form and function. However, doubts exist as to whether or not evolutionary distinctiveness truly serves as a proxy for functional distinctiveness, and, therefore, if the prominent use of EDGE lists by conservation practitioners adequately protects functional distinctiveness. To address this, we conducted a direct global comparison of EDGE against FUSE. Unlike EDGE, FUSE directly measures and prioritises functional distinctiveness. Here, we compare EDGE and FUSE scores for two well-studied groups: mammals (n = 5319 species) and birds (n = 7932 species). These groups are central to global conservation and, until now, have not been assessed under FUSE. We find that species rankings under EDGE and FUSE differ significantly, highlighting that these two metrics capture distinct, complementary aspects of biodiversity. This suggests that conservation strategies based solely on EDGE may overlook species with critical functional roles. Rather than assuming alignment between evolutionary and functional distinctiveness, we propose integrating both within a single measure, leveraging the strengths and benefits of each. To this end, we present a new conservation metric - EFUSE (Evolutionarily and Functionally Unique, Specialised, and Endangered) - which incorporates both evolutionary and functional distinctiveness into a single measure. EFUSE ensures that important components of biodiversity, which relate to ecosystem functioning, natures future contributions to people, and the intrinsic value of species, are adequately maximised in conservation decision-making.

ecology↗

bioRxiv2021

Wrack enhancement of post-hurricane vegetation and geomorphological recovery in a coastal dune

Coastal ecosystems such as sand dunes, mangrove forests, and salt marshes provide natural storm protection for vulnerable shorelines. At the same time, storms erode and redistribute biological materials among coastal systems via wrack. Yet how such cross-ecosystem subsidies affect post-storm recovery is not well understood. Here, we report an experimental investigation into the effect of storm wrack on eco-geomorphological recovery of a coastal embryo dune in north-eastern Florida, USA, following hurricane Irma. We contrasted replicated 100-m2 wrack-removal and unmanipulated (control) plots, measuring vegetation and geomorphological responses over 21 months. Relative to controls, grass cover was reduced 4-fold where diverse storm wrack, including seagrass rhizomes, seaweed, and wood, was removed. Wrack removal was also associated with a reduction in mean elevation, which persisted until the end of the experiment when removal plots had a 14% lower mean elevation compared to control plots. These results suggest that subsides of wrack re-distributed from other ecosystem types (e.g. seagrasses, macroalgae, uplands): i) enhances the growth of certain dune-building grasses; and ii) boosts the geomorphological recovery of coastal dunes. Our study also indicates that the practice of post-storm beach cleaning to remove wrack - a practice widespread outside of protected areas - may undermine the resilience of coastal dunes and their services.

ecology↗

bioRxiv2020

Functionally unique, specialised, and endangered (FUSE) species: towards integrated metrics for the conservation prioritisation toolbox

Identifying species with disproportionate contributions to biodiversity can lead to effective conservation prioritisation. Despite well-established methods for identifying endangered species adding inordinately to evolutionary diversity, in this context functional diversity has been overlooked. Here, we compare different metrics designed to identify threatened species that contribute strongly to functional diversity. We use the diverse and threatened global marine megafauna as a case study. We found that functional contributions of species are not fully captured in a single metric. Although we found a very strong correlation between functional specialisation and distinctiveness, functional uniqueness was only moderately correlated with the other two metrics and identified a different set of top-10 species. These functional contributions were then integrated and combined with extinction risk to identify species that are both important contributors to functional diversity and endangered. For instance, the top-10 Functionally Unique Specialized and Endangered (FUSE) species contains three critically endangered, five endangered and two vulnerable species which - despite comprising only 3% of species - are among the top 10% most functionally unique and hold 15% of the global functional richness. The FUSE index was remarkably robust to different mathematical formulations. Combining one or more facets of a species contribution to functional diversity with endangerment, such as with the FUSE index, adds to the toolbox for conservation prioritisation. Nevertheless, we discuss how these new tools must be handled with care alongside other metrics and information.

ecology↗

bioRxiv2019

Traditional functional groups capture limited variation in the trait space of macroalgae

O_LIMacroalgal (seaweed) beds and forests fuel coastal ecosystems and are rapidly reorganising under global change, but quantifying their functional structure still relies on binning species into coarse groups on the assumption that they adequately capture relevant underlying traits.\nC_LIO_LITo interrogate this \"group gambit\", we first measured 12 traits relating to competitive dominance and resource economics across 95 macroalgal species collected from UK rocky shores. We then assessed trait variation explained by traditional grouping approaches consisting of (i) two highly-cited schemes based on gross morphology and anatomy and (ii) two commonly-used categorisations of vertical space use. To identify the limitations of traditional grouping approaches and to reveal potential alternatives, we also assessed the ability of (iii) emergent groups created from post hoc clustering of our dataset to account for macroalgal trait variation.\nC_LIO_LI(i) Traditional groups explained about a third of multivariate trait expression with considerable group overlap. (ii) Classifications of vertical space use accounted for even less multivariate trait expression. Notwithstanding considerable overlap, the canopy vs. turf scheme explained significant differences in most individual traits, with turf species tending to display attributes of opportunistic forms. (iii) Emergent groups were substantially more parsimonious than all existing grouping approaches.\nC_LIO_LISynthesis: Our analysis using a comprehensive dataset of directly measured functional traits failed to strongly support the group gambit in macroalgae. While existing grouping approaches may allow first order approximations, they risk considerable loss of information at the trait and, potentially, ecosystem levels. We call for further development of a trait-based approach to macroalgal functional ecology to capture unfolding community and ecosystem changes with greater accuracy and generality.\nC_LI

ecology↗

bioRxiv2019

Applying continuous functional traits to large brown macroalgae: variation across tidal emersion and wave exposure gradients

A functional trait-based approach seeks a general understanding of organism - environment interactions, but, among primary producers, its empirical basis rests on vascular plants. We hypothesised that with increasing intertidal elevation, traits of large brown macroalgae would reflect a resource-acquisition vs. conservation (stress tolerance) trade-off at species and community levels. Across the elevation gradient at four UK sites of varying wave exposure, we: i) screened species relevant morphological traits, using principal component analysis to reduce dimensionality; and ii) up-scaled species traits using community weighted trait means (CWMs). The first principal component (PC1) strongly related to specific thallus area and thallus dry matter content, representing an acquisition - conservation trade-off. Although species generally shifted to the conservative end of this axis as elevation increased, mid-shore Ascophyllum nodosum sat at the extreme conservative end. PC2 associated with holdfast ratio, thickness and length, with A. nodusum scoring higher than other mid-shore species. CWMs of PC1 decreased with elevation at two sites indicating a shift from fast to slow ecosystem functioning, but this relationship was disrupted by A. nodusum at the sheltered site, and by the up-shore extent of Laminaria digitata at the most exposed site. The anomalous traits of A. nodusum reflect its unique competitive strategy (slow, persistent growth) in the relatively stressful mid-shore. Seaweed functional traits show promise in linking species identities to their strategies and ecosystem contributions. However, because resource conservation traits can be related to competitive as well as stress tolerance strategies, predicting seaweed trait responses to environmental stress gradients is challenging.

ecology↗

bioRxiv2017

WDR5 stabilizes actin architecture to promote multiciliated cell formation

HIGHLIGHTS O_LIWDR5 has an H3K4 independent role in the formation of multiciliated cells.\nC_LIO_LIWDR5 controls apical cell expansion, basal body patterning, and ciliogenesis in multiciliated cells.\nC_LIO_LIWDR5 localizes near the ciliary base where it connects basal bodies to F-actin.\nC_LIO_LIWDR5 stabilizes the apical actin network in multiciliated cells.\nC_LI\n\nSUMMARYThe actin cytoskeleton is critical to shape cells and pattern intracellular organelles to drive tissue morphogenesis. In multiciliated cells (MCCs), apical actin forms a lattice that drives expansion of the cell surface necessary to host hundreds of cilia. The actin lattice also uniformly distributes basal bodies across this surface. This apical actin network is dynamically remodeled, but the molecules that regulate its architecture remain poorly understood. We identify the chromatin modifier, WDR5, as a regulator of apical F-actin in multiciliated cells. Unexpectedly, WDR5 functions independently of chromatin modification in MCCs. Instead, we discover a scaffolding role for WDR5 between the basal body and F-actin. Specifically, WDR5 binds to basal bodies and migrates apically, where F-actin organizes around WDR5. Using a monomer trap for G-actin, we show that WDR5 stabilizes F-actin to maintain apical lattice architecture. In summary, we identify a novel, non-chromatin role for WDR5 in stabilizing F-actin in multiciliated cells.\n\nIN BRIEFKulkarni et al discover a chromatin independent function for WDR5 in multiciliated cell formation. WDR5 localizes to the base of cilia and functions as a scaffold between the basal bodies and the apical actin lattice. There, WDR5 stabilizes the actin lattice that allows multiciliated cells to expand their apical surface, pattern basal bodies, and generate hundreds of cilia.

developmental biology↗

bioRxiv2017

RAPGEF5 regulates nuclear transport of β-catenin

Canonical Wnt signaling coordinates many critical aspects of embryonic development, while dysregulated Wnt signaling contributes to common diseases, including congenital malformations and cancer. The nuclear localization of {beta}-catenin is the defining step in pathway activation. However, despite intensive investigation, the mechanisms regulating {beta}-catenin nuclear transport remain undefined. In a patient with congenital heart disease and heterotaxy, a disorder of left-right patterning, we previously identified the guanine nucleotide exchange factor, RAPGEF5. Here, we demonstrate that RAPGEF5 regulates left-right patterning via Wnt signaling. In particular, RAPGEF5, regulates the nuclear translocation of {beta}-catenin independently of both {beta}-catenin cytoplasmic stabilization and the importin {beta}1/Ran mediated transport system. We propose a model whereby RAPGEF5 activates the nuclear GTPases, Rap1/2, to facilitate the nuclear transport of {beta}-catenin, defining a parallel nuclear transport pathway to Ran. Our results suggest new targets for modulating Wnt signaling in disease states.

developmental biology↗