MARTI J. ANDERSON results 34
· Newest (Page 1/2, per page 25)
Author: MARTI J. ANDERSON ×Clear All Filters
Search Results
Coral reefs are threatened by climate change and overfishing, putting pressure on these sensitive ecosystems. Mesophotic habitats (> 30 m) contain diverse marine assemblages in depths where coral cover declines, yet they remain poorly studied compared to shallow coral habitats. We surveyed fish assemblages using stereo-video transects recorded with a Remotely Operated Vehicle (ROV) across six benthic mesophotic habitats in a m...
Radiographic Assessment of Bone Maturation: A Tool to Estimate Sexual Maturity in Common Dolphins ( Delphinus delphis )?NARA Subscribed
Accurate inference of sexual maturity is fundamental to interpreting marine mammal life histories and population structure. Using Bayesian logistic regression models with a hierarchical ordinal (HOF‐style) parameterisation and canonical analysis of principal coordinates (CAP), we evaluate skeletal metrics in the pectoral flippers of common dolphin ( Delphinus delphis ) as indicators of attainment of sexual maturity. HOF models...
Interpretable deep learning reveals spatiotemporal MRI features of brain aging that align with neurodegenerationNARA Subscribed
Cortical thinning and atrophy are hallmarks of brain aging that have been characterized using magnetic resonance imaging (MRI). Brain aging involves many neuroanatomic features whose effects on brain structure remain unexplored. To address this challenge, we trained interpretable deep neural networks (DNNs) to estimate brain age (BA) from T 1 -weighted ( T 1 w) MRI. By identifying MRI features unapparent to humans, DNNs can fi...
Alzheimer’s disease (AD) disproportionately affects women and carriers of the apolipoprotein E ε4 allele (APOE4), yet little is known about how sex and APOE interact to influence white matter (WM) integrity during disease progression. We integrated diffusion MRI and matched blood transcriptomic data to investigate these interactions and their underlying biological mechanisms. WM microstructure was quantified using diffusion te...
Predicting the progression of MCI and Alzheimer’s disease on structural brain integrity and other features with machine learningNARA Subscribed
Machine learning (ML) on structural MRI data shows high potential for classifying Alzheimer’s disease (AD) progression, but the specific contribution of brain regions, demographics, and proteinopathy remains unclear. Using Alzheimer’s Disease Neuroimaging Initiative (ADNI) data, we applied an extreme gradient-boosting algorithm and SHAP (SHapley Additive exPlanations) values to classify cognitively normal (CN) older adults, th...
Species' responses to broad‐scale environmental or spatial gradients are typically unimodal. Current models of species' responses along gradients tend to be overly simplistic (e.g., linear, quadratic or Gaussian GLMs), or are suitably flexible (e.g., splines, GAMs) but lack direct ecologically interpretable parameters. We describe a parametric framework for s pecies‐ e nvironment n on‐ l inear m odelling (‘ senlm ’). The frame...
Until recently, polar night constituted truly a “ mare incognitum ” of our times. Yet, the first records from this very little-explored period showcased a surprisingly rich and active ecosystem. This investigation aims to reveal the level of scavenger activity during both Arctic polar night and day. It compares the shallow-water scavenging fauna observed during two contrasting seasons (winter vs. summer) in a high Arctic fjord...
Microbiome and environment explain the absence of correlations between consumers and their diet in Bornean microsnailsNARA Subscribed
Classical ecological theory posits that species partition resources such that each species occupies a unique resource niche. In general, the availability of more resources allows more species to co‐occur. Thus, a strong relationship between communities of consumers and their resources is expected. However, correlations may be influenced by other layers in the food web, or by the environment. Here we show, by studying the relat...
Determining the importance of physical and biological drivers in shaping biodiversity in diverse ecosystems remains a global challenge. Advancements have been made towards this end in large marine ecosystems with several studies suggesting environmental forcing as the primary driver. However, both empirical and theoretical studies point to additional drivers of changes in diversity involving trophic interactions and, in partic...
Aim Phylogenies are increasingly used in community ecology, biogeography and macroecology. However, sourcing a phylogeny comprising the entire species pool for a focal region can be difficult. Typically, a bespoke phylogeny must be created requiring considerable data manipulation and the use of many standalone software packages. Here we present a suite of methodological tools within the popular R environment that help to build...
Measures of precision for dissimilarity‐based multivariate analysis of ecological communitiesNARA Subscribed
Ecological studies require key decisions regarding the appropriate size and number of sampling units. No methods currently exist to measure precision for multivariate assemblage data when dissimilarity‐based analyses are intended to follow. Here, we propose a pseudo multivariate dissimilarity‐based standard error ( MultSE ) as a useful quantity for assessing sample‐size adequacy in studies of ecological communities. Based on s...
Longitudinal variation and effects of habitat on biodiversity of Australasian temperate reef fishesNARA Subscribed
Aim Latitudinal gradients in marine biodiversity of fishes are well documented but comparatively little is known about longitudinal patterns. The objective of this study was to describe the distributional patterns in biodiversity and assemblage structure of temperate reef‐associated fishes in two habitats (kelp forests and open reefs) in each of four regions at comparable latitudes spanning a large longitudinal range (> 5000 k...
Stochastic and deterministic drivers of spatial and temporal turnover in breeding bird communitiesNARA Subscribed
Aim A long‐standing challenge in ecology is to identify the suite of factors that lead to turnover in species composition in both space and time. These factors might be stochastic (e.g. sampling and priority effects) or deterministic (e.g. competition and environmental filtering). While numerous studies have examined the relationship between turnover and individual drivers of interest (e.g. primary productivity, habitat hetero...
Incorporating the intraspecific occupancy–abundance relationship into zero‐inflated modelsNARA Subscribed
Zero‐inflated versions of standard distributions for count data are often required in order to account for excess zeros when modeling the abundance of organisms. Such distributions typically have as parameters λ, the mean of the count distribution, and π, the probability of an excess zero. Implementations of zero‐inflated models in ecology typically model λ using a set of predictor variables, and π is fit either as a constant...
The effects of translocation‐induced isolation and fragmentation on the cultural evolution of bird songNARA Subscribed
Understanding the divergence of behavioural signals in isolated populations is critical to knowing how certain barriers to gene flow can develop. For many bird species, songs are essential for conspecific recognition and mate choice. Measuring the rate of song divergence in natural populations is difficult, but translocations of endangered birds to isolated islands for conservation purposes can yield insights, as the age and s...
Biogeographical patterns of algal communities in the Mediterranean Sea: Cystoseira crinita ‐dominated assemblages as a case studyNARA Subscribed
Aim The aim of this study was to describe the composition, community structure and biogeographical variation of subtidal algal assemblages dominated by the brown alga Cystoseira crinita across the Mediterranean Sea. Location The Mediterranean coast, from Spain (1°25′ E) to Turkey (30°26′ E). Methods Data on the species composition and structure of assemblages dominated by the species C. crinita were collected from 101 sites in...
Understanding the causes of spatial variation in species richness is a major research focus of biogeography and macroecology. Gridded environmental data and species richness maps have been used in increasingly sophisticated curve‐fitting analyses, but these methods have not brought us much closer to a mechanistic understanding of the patterns. During the past two decades, macroecologists have successfully addressed technical p...
Species abundance distributions: moving beyond single prediction theories to integration within an ecological frameworkNARA Subscribed
Species abundance distributions (SADs) follow one of ecology’s oldest and most universal laws – every community shows a hollow curve or hyperbolic shape on a histogram with many rare species and just a few common species. Here, we review theoretical, empirical and statistical developments in the study of SADs. Several key points emerge. (i) Literally dozens of models have been proposed to explain the hollow curve. Unfortunatel...
Poster abstractsNARA Subscribed
Multivariate dispersion as a measure of beta diversityNARA Subscribed
Beta diversity can be defined as the variability in species composition among sampling units for a given area. We propose that it can be measured as the average dissimilarity from individual observation units to their group centroid in multivariate space, using an appropriate dissimilarity measure. Differences in beta diversity among different areas or groups of samples can be tested using this approach. The choice of transfor...