Species distribution model transferability and model grain size - finer may not always be better.
Ontology highlight
ABSTRACT:
SUBMITTER: Manzoor SA
PROVIDER: S-EPMC5940916 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Using existing data can be a reliable and cost-effective way to predict species distributions, and particularly useful for recovering or expanding species. We developed a current gray wolf (Canis lupus) distribution model for the western Great Lakes region, USA, and evaluated the spatial transferability of single-state models to the region. This study is the first assessment of transferability in a wide-ranging carnivore, as well as one of few developed for large spatial extents. We collected 3500 wolf locations from winter surveys in Minnesota (2017-2019), Wisconsin (2019-2020), and Michigan (2017-2020). We included 10 variables: proportion of natural cover, pastures, and crops; distance to natural cover, agriculture, developed land, and water; major and minor road density; and snowfall (1-km res.). We created a regional ensemble distribution by weight-averaging eight models based on their performance. We also developed single-state models, and estimated spatial transferability using two approaches: state cross-validation and extrapolation. We assessed performance by quantifying correlations, receiver operating characteristic curves (ROC), sensitivities, and two niche similarity indices. The regional area estimated to be most suitable for wolves during winter (threshold = maximum sensitivity/specificity) was 106,465 km2 (MN = 48,083 km2, WI = 27,757 km2, MI = 30,625 km2) and correctly predicted 88% of wolf locations analyzed. Increasing natural cover and distance to crops were consistently important for determining regional and single-state wolf distribution. Extrapolation (vs. cross-validation) produced results with the greatest performance metrics, and were most similar to the regional model, yet good internal performance was unrelated to greater extrapolation performance. Factors influencing species distributions are scale-dependent and can vary across areas due to behavioral plasticity. When extending inferences beyond the current occurrence of individuals, assessing variation in ecology such as habitat selection, as well as methodological factors including model performance, will be critical to avoid poor scientific interpretations and develop effective conservation applications. In particular, accurate distribution models for recovering or recovered carnivores can be used to develop plans for habitat management, quantify potential of unoccupied habitat, assess connectivity modeling, and mitigate conflict, facilitating long-term species persistence.
| S-EPMC9359985 | biostudies-literature
Project description:Total Grain-Size Distribution (TGSD) of tephra deposits is key to the characterization of explosive volcanism, plume-dispersal modeling, and magmatic fragmentation studies. Nonetheless, various aspects that includes deposit exposure and data fitting make its determination extremely complex and affect its representativeness. In order to shed some lights on the reliability of derived TGSDs, we examine a large TGSD dataset in combination with a sensitivity analysis of sampling strategies. These analyses are based both on a well-studied tephra deposit and on synthetic deposits associated with a variety of initial eruptive and atmospheric conditions. Results demonstrate that TGSDs can be satisfactorily fitted by four distributions (lognormal, Rosin-Rammler, and power-law based either on the absolute or cumulative number of particles) that capture different distribution features. In particular, the Rosin-Rammler distribution best reproduces both the median and the tails of the TGSDs. The accuracy of reconstructed TGSDs is strongly controlled by the number and distribution of the sampling points. We conclude that TGSDs should be critically assessed based on dedicated sampling strategies and should be fitted by one of the mentioned theoretical distributions depending on the specific study objective (e.g., tephra-deposit characterization, physical description of explosive eruptions, tephra-dispersal modeling).
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Project description:Most species are believed to evolve larger body sizes over evolutionary time. Previous studies have suggested that sexual selection, through male-male competition and female choice, favors larger males. However, there is little evidence of selection against large size. The female serrate-legged small treefrogs (Philautus odontotarsus) must carry passive males from leks to breeding grounds over relatively long distances after amplexus to find a suitable place to lay eggs. The costs of large male size may therefore decrease mating success due to reduced agility and/or higher energy requirements. Thus, we hypothesized that selection would not favor larger males in P. odontotarsus. Females can assess male body size on the basis of the dominant frequency of male calls in frogs. To assess female P. odontotarsus preferences for a potential mate's body size, male calls of high, average and low dominant frequency were played back to the females in phonotaxis experiments. Results showed that most females prefer the advertisement call with average dominant frequency. In addition, we compared the body mass distribution of amplectant males with that of single males in nature. The body masses of amplectant males are more narrowly distributed in the intermediate range than that of single males. The phonotaxis results and the data of actual female preferences in the field show that females strongly prefer potential mates of mean body sizes, consistent with the view that, in this species at least, larger males are not always perceived as better by females. In the present study, P. odontotarsus provides an example of an amphibian species in which large size does not have an advantage in mating success for males. Instead, our results provide evidences that stabilizing selection favors the optimal intermediate size of males.
| S-EPMC4762700 | biostudies-literature
Project description:Background: Fidelity in simulation is an important design feature. Although it is typically seen as bipolar (i.e., "high" or "low"), fidelity is actually multidimensional. There are concerns that "low fidelity" might impede the immersion of learners during simulation training. "Locally built models" are characterized by decreased cost and reduced "structural" fidelity (how the simulator looks) while satisfying "functional" fidelity (what the simulator does). Objective: To 1) describe the use of a locally built chest tube model in building a mastery-based simulation curriculum and 2) describe evaluation of the model from learners in different stages and contexts. Methods: The model was built on the basis of key functional features of the assigned training task. A curriculum that combined progressive difficulty and opportunities for deliberate practice and mastery was developed. An analysis of the learner's survey responses was performed using SAS studio (SAS Software). Results: We describe the process of creating the chest tube model and a curriculum in which the model is used for increasing levels of difficulty to reach skill mastery. Learners at different stages and in different contexts, such as practicing physicians and trainees from developed and developing countries, evaluated the model similarly. We provide validity evidence for the content, response process, and relationship with other variables when using the model in the assessment of chest tube insertion skills. Conclusion: As demonstrated in our chest tube critical care medicine curriculum, the locally built models are simple to build and feasible to use. Contrary to current thinking that low-fidelity models might impede immersion in simulation training for experienced learners, the survey results show that different learners provide very similar evaluations after practicing with the model.
| S-EPMC8043267 | biostudies-literature
Project description:Here, we respond to Booth's criticism of our paper, "Predictive ability of a process-based versus a correlative species distribution model." Booth argues that our usage of the MaxEnt model was flawed and that the conclusions of our paper are by implication flawed. We respond by clarifying that the error Booth implies we made was not made in our analysis, and we repeat statements from the original manuscript which anticipated such criticisms. In addition, we illustrate that using BIOCLIM variables in a MaxEnt analysis as recommended by Booth does not change the conclusions of the original analysis. That is, high performance in the training data domain did not equate to reliable predictions in novel data domains, and the process model transferred into novel data domains better than the correlative model did. We conclude by discussing a hidden implication of our study, namely, that process-based SDMs negate the need for BIOCLIM-type variables and therefore reframe the variable selection problem in species distribution modeling.
| S-EPMC8495818 | biostudies-literature
Project description:Despite its theoretical relationship, the effect of body size on the performance of species distribution models (SDM) has only been assessed in a few studies, and to date, the evidence shows unclear results. In this context, Chilean fishes provide an ideal case to evaluate this relationship due to their short size (fishes between 5 cm and 40 cm) and conservation status, providing evidence for species at the lower end of the worldwide fish size distribution and representing a relevant management tool for species conservation. We assessed the effect of body size on the performance of SDM in nine Chilean river fishes, considering the number of records, performance metrics, and predictor importance. The study was developed in the Bueno and Valdivia basins of southern Chile. We used a neural network modeling algorithm, training models with a cross-validation scheme. The effect of fish size on selected metrics was assessed using linear models and beta regressions. While no relationship between fish size and the number of presences was found, our results indicate that the model specificity increases with fish size. Additionally, the predictive importance of Riparian Vegetation and Within-Channel Structures variables decreases for larger species. Our results suggest that the relationship between the grain of the dataset and the home range of the species could bias SDM, leading in our case, to overprediction of absences. We also suggest that evolutionary adaptation to low slopes among Chilean fishes increases the relevance of riparian vegetation in the SDMs of smaller species. This study provides evidence on how species size may bias SDM, which could potentially be corrected by adjusting the model grain.
| S-EPMC6901005 | biostudies-literature
Project description:Many studies assume that an increase in brain size is beneficial. However, the costs of producing and maintaining a brain are high, and we argue that brain size should be secondarily reduced by natural selection whenever the costs outweigh the benefits. Our results confirm this by showing that brain size is subject to bidirectional selection. Relative to the ancestral state, brain size in bats has been reduced in fast flyers, while it has increased in manoeuvrable flyers adapted to flight in complex habitats. This study emphasizes that brain reduction and enlargement are equally important, and they should both be considered when investigating brain size evolution.
| S-EPMC1617168 | biostudies-literature
Project description:The radii and orbital periods of 4,000+ confirmed/candidate exoplanets have been precisely measured by the Kepler mission. The radii show a bimodal distribution, with two peaks corresponding to smaller planets (likely rocky) and larger intermediate-size planets, respectively. While only the masses of the planets orbiting the brightest stars can be determined by ground-based spectroscopic observations, these observations allow calculation of their average densities placing constraints on the bulk compositions and internal structures. However, an important question about the composition of planets ranging from 2 to 4 Earth radii (R⊕) still remains. They may either have a rocky core enveloped in a H2-He gaseous envelope (gas dwarfs) or contain a significant amount of multicomponent, H2O-dominated ices/fluids (water worlds). Planets in the mass range of 10-15 M⊕, if half-ice and half-rock by mass, have radii of 2.5 R⊕, which exactly match the second peak of the exoplanet radius bimodal distribution. Any planet in the 2- to 4-R⊕ range requires a gas envelope of at most a few mass percentage points, regardless of the core composition. To resolve the ambiguity of internal compositions, we use a growth model and conduct Monte Carlo simulations to demonstrate that many intermediate-size planets are "water worlds."
| S-EPMC6525489 | biostudies-literature
Project description:BackgroundRecent data suggest that highly elevated high-density lipoprotein cholesterol (HDL-C) may not always protect against cardiovascular disease. To what degree this is true in type 1 diabetes is unknown, although cardiovascular risk is increased despite elevated mean HDL-C.ObjectiveTo reassess the association between HDL-C and its subfractions with coronary artery disease (CAD) in childhood-onset type 1 diabetes.MethodsEpidemiology of Diabetes Complications study participants free of CAD at baseline (301 men, 298 women; mean age, 27.1 and diabetes duration, 18.9 years) were studied. CAD was defined as angina, ischemic electrocardiogram changes, confirmed myocardial infarction, angiographic stenosis ≥50%, revascularization, or CAD death. Cholesterol in the HDL fraction and HDL3 cholesterol subfraction was measured enzymatically after precipitation with heparin/manganese and dextran sulfate, respectively.ResultsDuring 18 years of follow-up, 29.5% of men and 25.5% of women developed CAD. Although a linear decrease in incidence was observed with increasing HDL-C concentration in men, incidence increased in women at less than 47 mg/dL and greater than 80 mg/dL. These patterns largely reflected the HDL3 cholesterol-CAD association. After multivariable adjustment, the linear, inverse, HDL-C/CAD association persisted in men (hazard ratio [HR] 0.97, 95% confidence interval [CI] 0.94-0.99); in women, the U-shaped relationship lost significance. HDL3 cholesterol remained multivariably associated with CAD in both men (linear association, P = .03) and women (HR 2.31 (95% CI 1.31-4.08) and HR 1.80 (95% CI 1.01-3.23) for the lowest and highest versus the middle quintiles, respectively).ConclusionThe increased CAD risk in women for an HDL-C >80 mg/dL in type 1 diabetes merits further study. Gender specificity could not be determined as only two men had HDL-C >80 mg/dL.
| S-EPMC3190122 | biostudies-literature