Aspects of genetic and morphological variation in selected new world land birds

Thesis (M.S.) University of Alaska Fairbanks, 2000The objective of this thesis is to examine variation in certain New World land birds, focusing on morphological difference at the intraspecific level and genetic differences at the intra- and interspecific levels. First, I investigate sexual dimorphism in the Wilson's Warbler (Wilsonia pusilla), a Nearctic-Neotropic migrant parulid. Using museum specimens, I quantify the degree of dimorphism and devise a method to distinguish the sexes using morphological measurements. Second, I outline a new method of approximating Weir and Cockerham's 0 (1984, 1993), an unbiased estimator of genetic population structure. The method uses commonly published parameters and obviates the need to recode existing allozyme data sets to calculate 0. The estimation algorithm is shown to be useful for both model populations and real-world avian populations

Integrated Specimen-Based Studies of Philippine Birds and Avian Influenza: Applications in Conservation, Taxonomy, Wildlife Enforcement, and Disease

Conservation is practiced in many ways, but often overlooked is the role of specimens in conservation biological research. With increasingly powerful phylogenetic analyses necessary to describe dwindling genetic diversity, the preservation of biodiversity can only be as successful as the infrastructure of specimens available. Taxonomic units of biodiversity may not completely reflect true genetic diversity, so new phylogenetic tools useful for the recognition of biodiversity require specimen-based resources to be as complete as possible. Here, we discuss how specimen-based, integrated research has multiple goals, and how conservation biology remains a key focus and outcome of these studies. Our sample archiving methods are among the most comprehensive in the discipline, and critical for quality research in conservation, phylogenetics, taxonomy, wildlife enforcement, and avian influenza studies. Although we have not isolated any avian influenza from Philippine samples, we have learned much from these negative results about avian influenza in the Philippines, and our methodology is producing quality multidisciplinary science

Estimating the unbiased estimator θ for population genetic survey data

We consider a method of approximating Weir and Cockerham\u27s θ, an unbiased estimator of genetic population structure, using values readily available from published studies using biased estimators (Wright\u27s FST or Nei\u27s GST). The estimation algorithm is shown to be useful for both model populations and real-world avian populations. However, the correlation between Wright\u27s FST and Weir and Cockerham\u27s θ is strong when compared among 39 empirical avian datasets. Thus, the advantage of approximating an unbiased estimator is unclear considering the small actual effect of θ\u27s bias-removing power on empirical datasets

For scientists, for students or for the public? : the shifting roles of natural history museums

This article aims to discuss the main roles of natural history museums and to show how these purposes have evolved and adapted throughout the museums’ history, as a response to the development of natural sciences and societal change, from their creation in the 18th century to the present. It strives to demonstrate how the balance between research, teaching and disseminating knowledge to the public has successively shifted, without ever forsaking any of these functions. It is focused on Portuguese museums, but examining their place within international trends

Accelerational Implications of Hummingbird Display Dives

Integrative Biolog

Decadal changes and delayed avian species losses due to deforestation in the northern Neotropics

How avifauna respond to the long-term loss and fragmentation of tropical forests is a critical issue in biodiversity management. We use data from over 30 years to gain insights into such changes in the northernmost Neotropical rainforest in the Sierra de Los Tuxtlas of southern Veracruz, Mexico. This region has been extensively deforested over the past half-century. The Estación de Biología Tropical Los Tuxtlas, of the Universidad Nacional Autónoma de México (UNAM), protects a 640 ha tract of lowland forest. It became relatively isolated from other forested tracts between 1975 and 1985, but it retains a corridor of forest to more extensive forests at higher elevations on Volcán San Martín. Most deforestation in this area occurred during the 1970s and early 1980s. Forest birds were sampled on the station and surrounding areas using mist nets during eight non-breeding seasons from 1973 to 2004 (though in some seasons netting extended into the local breeding season for some species). Our data suggested extirpations or declines in 12 species of birds subject to capture in mist nets. Six of the eight species no longer present were captured in 1992–95, but not in 2003–2004. Presence/absence data from netting and observational data suggested that another four low-density species also disappeared since sampling began. This indicates a substantial time lag between the loss of habitat and the apparent extirpation of these species. Delayed species loss and the heterogeneous nature of the species affected will be important factors in tropical forest management and conservation

The Global Status of Freshwater Fish Age Validation Studies and a Prioritization Framework for Further Research

Age information derived from calcified structures is commonly used to estimate recruitment, growth, and mortality for fish populations. Validation of daily or annual marks on age structures is often assumed, presumably due to a lack of general knowledge concerning the status of age validation studies. Therefore, the current status of freshwater fish age validation studies was summarized to show where additional effort is needed, and increase the accessibility of validation studies to researchers. In total, 1351 original peer-reviewed articles were reviewed from freshwater systems that studied age in fish. Periodicity and age validation studies were found for 88 freshwater species comprising 21 fish families. The number of age validation studies has increased over the last 30 years following previous calls for more research; however, few species have validated structures spanning all life stages. In addition, few fishes of conservation concern have validated ageing structures. A prioritization framework, using a combination of eight characteristics, is offered to direct future age validation studies and close the validation information gap. Additional study, using the offered prioritization framework, and increased availability of published studies that incorporate uncertainty when presenting research results dealing with age information are needed