Fish assemblages play a key role in stream ecosystems, and play a crucial role in the assessment of stream health. Physical habitat is a key component of stream ecosystems and plays a major role in determining biotic assemblages and stream integrity. There is increasing recognition of the role landscape factors play in determining biotic assemblages and stream integrity. Landscapes in Iowa and ...

The overall goal of this project is to improve our understanding of beaked whale distribution and foraging behavior and to describe inter-specific differences. We are developing habitat models for multiple beaked whale species in the Southern California Bight using passive acoustic encounters. Data from line transect surveys and autonomous recorders are compared with dynamic and static oceanogr...

It has been difficult to understand the effects of habitat structure on assemblages because the different elements of habitat structure are often confounded. For example, few studies consider that the effects of structural components of a habitat (rocks, trees, pits, pneumatophores) may be separate from the complexity (e.g. surface area {SA}) they create. From prior observations and experiments...

Mediterranean endemic freshwater fish are among the most threatened biota in the world. Distinguishing the role of different extinction drivers and their potential interactions is crucial for achieving conservation goals. While some authors argue that invasive species are a main driver of native species declines, others see their proliferation as a co-occurring process to biodiversity loss driv...

We used repeated sightings of individual birds encountered in community-level surveys to investigate the relative roles of habitat and biological interactions in determining the distribution and abundance of each species. To analyze these data, we developed a multispecies N-mixture model that allowed estimation of both positive and negative correlations between abundances of different species w...

Management of critical habitat for threatened species with small ranges requires location-specific, fine-scale survey data. The silver-headed antechinus (Antechinus argentus) is known from only two isolated, fire-prone locations. At least one of these populations, at Kroombit Tops National Park in central-eastern Queensland, Australia, possesses a very small range. Here, we present detailed veg...

1. Non-volant animals in tropical rain forests differ in their ability to exploit the habitat above the forest floor and also in their response to habitat variability. It is predicted that specific movement trajectories are determined both by intrinsic factors such as ecological specialization, morphology and body size and by structural features of the surrounding habitat such as undergrowth an...

1. Two dominant drivers of species distributions are climate and habitat, both of which are changing rapidly. Understanding the relative importance of variables that can control distributions is critical, especially for invasive species that may spread rapidly and have strong effects on ecosystems. 2. Here, we examine the relative importance of climate and habitat variables in controlling the d...

Land use change is a major threat to global biodiversity. Forest species face the dual threats of deforestation and intensification of forest management. In regions where forests are under threat, rural landscapes that retain structural components of mature forests potentially provide valuable additional habitat for some forest species. Here, we illustrate the habitat value of traditional wood ...

We develop the likelihood ratio criterion (LRC) for testing the coefficients of a structural equation in a system of simultaneous equations in econometrics. We relate the likelihood ratio criterion to the AR statistic proposed by Anderson and Rubin (1949, 1950), which has been widely known and used in econometrics over the past several decades. The method originally developed by Anderson and Ru...