Analysis of the Habitat Associations of a Hypothetical Beetle Species

A dataset for a hypothetical ground-dwelling beetle species is used to illustrate five methods of habitat analysis: (1) comparison of group means, (2) multiple linear regression, (3) multiple logistic regression, (4) classification and regression trees, and (5) principal components analysis. The dataset consists of abundance (counts of individuals) recorded in each of 100 small survey plots located throughout forested study sites. The following environmental predictor variables were measured in each plot: percentage canopy cover, depth of leaf litter, volume of woody debris, ratio of oak to non-oak trees, and soil type. Techniques for assessing normality of each variable and multicollinearity among variables are discussed and recommended prior to conducting the habitat analysis. Assumptions, strengths, and weaknesses of each method are discussed.

Types of Data and the General Framework of Analysis

For most habitat analyses, researchers typically collect and examine environmental data from the landscape scale (a few square kilometers to hundreds of square kilometers) all the way down to the scale of a microhabitat (tens of square meters). At the larger spatial extents, the data may be GIS-based such as spatially referenced land cover data. At smaller spatial scales, the data may be collected (variables measured) in the field at the study sites. Data for a habitat analysis are often based on randomly located and spatially delineated sampling or survey plots. The environmental data compose a set of a few to tens of predictor variables that are used in statistical tests for a relationship with the response variable that is typically species presence–absence, abundance (counts of individuals), or activity level. Depending on the spatial scale of analysis, predictor variables could represent different environmental variables such as vegetation structure, soil properties, and other characteristics of the substrate. Climate and weather variables are environmental, but they are not considered to be characteristics of the habitat. The formal habitat analysis consists of testing for a statistical relationship between the response variable and one or more environmental predictor variables so as to identify those variables that truly are habitat characteristics. A study of the habitat of the brown-throated sloth in Costa Rica is used to further explain the type of data used in characterizing the habitat of a species.

Environmental Drivers of Variation in Labial Teeth Number in Ascaphus Tadpoles

ABSTRACTAnuran tadpoles exhibit extraordinary diversity in mouthpart morphology, reflecting phylogenetic relationships, life history specializations, and ecological adaptations. In this study, we investigate patterns and potential environmental drivers of variation in labial teeth counts across and within the coastal tailed frog (Ascaphus truei) and the Rocky Mountain tailed frog (A. montanus), which together constitute the basal frog family Ascaphidae. Tailed frogs occupy cold, fast-flowing, high gradient streams in mesic forests of western North America, with differences in environmental conditions that reflect their coastal and continental distributions. Despite a very strong relationship between the number of labial teeth and developmental (Gosner) stage, we found significant relationships between tooth counts and site-specific environmental predictors after controlling for stage. The most important environmental predictor varied between the species, with percent canopy cover for A. truei and average benthic substrate size for A. montanus. There were also differences in the overall tooth counts between species, with A. truei having more teeth in all rows compared to A. montanus. These findings demonstrate that differences in oral morphology in response to local environmental conditions can override the homogenizing effects of gene flow in both Ascaphus species, likely through a combination of local adaptation and phenotypic plasticity. Follow-up investigations should include the assessment of community level variability across sites, and experimental tests to confirm functional relationships between environmental variation and oral morphology, in addition to partitioning genetic from plastic mechanisms.

Ecological niche modelling

Impact assessments increasingly rely on models to project the potential impacts of climate change on species distributions. Ecological niche models have become established as an efficient and widely used method for interpolating (and sometimes extrapolating) species’ distributions. They use statistical and machine-learning approaches to relate species’ observations to environmental predictor variables and identify the main environmental determinants of species’ ranges. Based on this estimated species–environment relationship, the species’ potential distribution can be mapped in space (and time). In this chapter, we explain the concept and underlying assumptions of ecological niche models, describe the basic modelling steps using the silvereye (Zosterops lateralis) as a simple real-world example, identify potential sources of uncertainty in underlying data and in the model, and discuss potential limitations as well as latest developments and future perspectives of ecological niche models in a global change context.

Resposta do Controle Postural em Superfície Inclinada: uma Revisão de Literatura

ResumoO controle postural é um requisito imprescindível para a execução das habilidades motoras durante as atividades de vida diária, logo, há a necessidade constante de ajuste dos segmentos corporais para garantir a autonomia e a independência da mobilidade humana. Os ajustes posturais são resultantes da interação do sistema sensório-motor e da sua correlação com o meio ambiente, produzindo orientação e estabilidade postural esperada durante a execução das atividades, sendo essa estática ou dinâmica. Deste modo, o objetivo do estudo foi apresentar os impactos funcionais ocorridos durante a posição de pé parada ou em movimento em superfície de inclinada, principalmente, entre os idosos. O estudo se fundamentou na revisão bibliográfica, no período temporal de 2006 a 2016, por meio da análise das bases de dados em Pubmed, Ebsco, SciELO, Medline e Lilacs, com a utilização dos termos: Plataforma de força, plano inclinado, plano horizontal e comportamento do centro de pressão. Os resultados apontaram que as situações rotineiras do dia a dia, realizadas em superfícies inclinadas, como um mero ato de subir ou até ficar parado em uma ladeira, pode ser um preditor ambiental para instabilidade postural, tornando-se necessário a reavaliação do olhar da intervenção terapêutica meramente clínica, passando a ampliar para as circunstâncias vinculadas com as questões da acessibilidade urbana. Palavras chaves: Plataforma de Força. Plano Horizontal. Comportamento do Centro de Pressão. Abstract Postural control is an essential requirement for the performance of motor skills during daily living activities, so there is a constant need to adjust body segments to guarantee the autonomy and independence of human mobility. Postural adjustments result from the interaction of the sensorimotor system and their correlation with the environment, producing orientation and postural stability expected during the execution of the activities, being static or dynamic. Thus, the objective of the study was to present the functional impacts occurred during standing or moving position on inclined surface, mainly among the elderly. The study was based on the bibliographic review, in the period from 2006 to 2016, through the analysis of databases in Pubmed, Ebsco, SciELO, Medline and Lilacs, using the terms Force platform, inclined plane, horizontal plane and pressure center behavior. The results showed that routine everyday situations on inclined surfaces, such as a mere act of climbing or even standing on a slope, may be an environmental predictor for postural instability, making it necessary to re-evaluate the clinical intervention, starting to extend the issues of urban accessibility to the related circumstances. Keywords: Force Platform. Horizontal Plane. Pressure Center Behavior.

ECOLOGICAL CHARACTERISTICS AND SUITABILITY EVALUATION OF FRITILLARIA CIRRHOSA D. DON BASED ON MAXENT MODEL

Background: As a rare and endangered medicinal plant growing in plateaus, Fritillaria cirrhosa D. Don is a scant resource in terms of quantity and planting regions. However, there is limited knowledge on predicting the potential ecological suitability of regions for the species with the climate factors. This paper evaluates the ecological suitability of F. cirrhosa D. Don on a global scale using Maxent. Materials and Methods: The ecologically suitable regions for F. cirrhosa D. Don around the world were evaluated using the maximum entropy model (Maxent), based on 127 known occurrence records and specific environmental predictor variables. Results: The Maxent model was highly accurate, with a statistically significant Area Under the Receiving Operator Curve (AUC) value of 0.993, and the most suitable areas and the suitable areas for F. cirrhosa D. Don were approximately 450,000 and 700,000 sq. km., respectively, including China, Pakistan, Nepal, and Bhutan. A quantitative study of the climatic characteristics of F. cirrhosa D. Don indicated that the period from May to October was critical for plant growth and development. Thus, the stable precipitation-temperature ratios (0.59 to 2.42) during this period could serve as a feature indicator for the geographical distribution of the plant. Conclusion: This work should be beneficial for the introduction and resource protection of F. cirrhosa D. Don, meanwhile, the analytical method could be expanded to predict the potential distribution of other medicinal plants.