Biology subjects

Hooker, G.

Publications and source records attributed to Hooker, G..

3 recordsLinked to original sources

bioRxiv2026

Primary productivity declines when species composition and climate are mismatched

Climate change drives shifts in species composition, but turnover in many communities lags behind the current pace of change. Anticipating the impact of the resulting community-climate disequilibria on ecosystem functioning is critical. Present-day communities may already be out of equilibrium with climate, providing an opportunity to estimate the effects of disequilibrium before they become more widespread. We analyzed plant community composition and function data from [~]60,000 rangeland monitoring sites across the western US to measure how community-climate disequilibrium contributes to spatial and temporal variation in net primary productivity (NPP) - a key ecosystem function. We found that communities were already substantially out of equilibrium with climate and accounting for this disequilibrium helped explain patterns of NPP. Communities farthest from equilibrium were less productive than those that were closely matched with climate. Our findings suggest that future increases in community-climate disequilibrium may further impair ecosystem functioning.

ecology↗

bioRxiv2022

Development and Validation of the Vanderbilt PRS-KS, an Instrument to Quantify Polygenic Risk Score Knowledge

PurposeAs polygenic risk scores (PRS) enter clinical practice, healthcare providers and the publics comprehension of PRS results are of great importance, yet poorly understood. We present the Vanderbilt Polygenic Risk Scores Knowledge Score (Vanderbilt PRS-KS), a tool to quantify PRS knowledge. MethodsThe Vanderbilt PRS-KS was developed by a team of genetic counselors and physicians to cover key conceptual facts pertaining to PRSs. We recruited (n=500) individuals with demographics representative of a U.S. sample and graduate-level healthcare students (n=74) at a large academic medical center to participate in this validation study. We evaluated the Vanderbilt PRS-KSs psychometric properties using confirmatory factor analysis (CFA) and item response theory (IRT). ResultsThe 7-item Vanderbilt PRS-KS correlated to a single latent construct on CFA ({Lambda}=0.31-0.61). The scale showed promising reliability (Cronbachs =0.66) with IRT summed scores of [≥]2 to [≤]5, demonstrating reliability > 0.70. The Vanderbilt PRS-KS significantly correlated with genetic knowledge and applied PRS knowledge (r=0.55, r=0.29), and graduate-level healthcare students had significantly higher scores compared to the representative sample (p<0.01). ConclusionsThe Vanderbilt PRS-KS is a rigorously validated measure to quantify PRS knowledge.

genetics↗

bioRxiv2018

Size-by-environment interactions: a neglected dimension of species’ responses to environmental variation

In both plant and animal systems, size can determine whether an individual survives and grows under different environmental conditions. However, it is less clear whether and when size-dependent responses to the environment affect population dynamics. Size-by-environment interactions create pathways for environmental fluctuations to influence population dynamics by allowing for negative covariation between sizes within vital rates (e.g., small and large individuals have negatively covarying survival rates) and/or size-dependent variability in a vital rate (e.g., survival of large individuals varies less than small individuals through time). Whether these phenomena affect population dynamics depends on how they are mediated by elasticities (they must affect the sizes and vital rates that matter) and their projected impacts will depend on model functional form (the impact of reduced variance depends on the relationship between the environment and vital rate). We demonstrate these ideas with an analysis of fifteen species from five semiarid plant communities. We find that size-by-environment interactions are common but do not impact long-term population dynamics. Size-by-environment interactions may yet be important for other species. Our approach can be applied to species in other ecosystems to determine if and how size-by-environment interactions allow them to cope with, or exploit, fluctuating environments.

ecology↗