Thesis (Ph. D.)--University of Florida, 1993. / Vita. Includes bibliographical references (leaves 587-658).

<p>The success of medusahead (Taeniatherum caput-medusae ssp. asperum) as an invasive exotic grass in the western US is attributed in part to its low palatability. The nutritional context where medusahead grows can be modulated by the use of supplements that increase herbivores? preference for unpalatable feeds. Additionally, positive experiences early in life (with mother, with supplements) can have long-life influences on preference for unpalatable feeds. To test the influence of the nutritional context on medusahead intake, ewes grazed with their lambs during summer of 2013 on medusahead-infested rangeland with (Treatment) or without (Control) the daily provision of an energy-rich supplement. To test for the effect of experience early in life at grazing medusahead on use of this weed later in life, lambs that grazed with their mothers during 2013 (Experienced) were exposed to medusahead (in pens and during grazing) as yearlings during summer of 2014 along with inexperienced (Control) animals. To better understand the unpalatability of medusahead, the fermentation kinetics of medusahead at different phenological stages and particle sizes was assessed. Ewes grazing with their lambs showed low use of medusahead (5% of the grazing events recorded), even when supplemented. Nevertheless, medusahead use increased across the grazing period and utilization was similar to medusahead abundance in the plant community. Use of medusahead by nursing lambs was correlated with that observed by their mothers and lambs utilized medusahead to the same extent either before or after weaning. Yearlings in pens showed low intake of medusahead and a cyclic pattern of intake across days. However, experienced yearlings displayed a more even intake of medusahead across days and a greater gain-to-feed ratio than Control yearlings. All yearlings showed low to nil use of medusahead during grazing. Medusahead had lower fermentation rates than alfalfa hay and fermentation rates declined with plant maturity. Organic matter digestibility for medusahead declined as particle size of the substrate increased, a relationship that explains the low palatability of the weed. These results provide the foundation for grazing treatments aimed at reducing the abundance of the weed or at preventing its spread in rangelands with different levels of medusahead infestations.

Thesis (Ph. D.)--University of Michigan, 1952. / Includes bibliographical references (leaves 330-335).

Thesis (M.S.)--University of Wisconsin--Madison, 1943. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

<p> Effective conservation of migratory species is hindered by a lack of knowledge of population links between breeding, wintering and stopover habitats. The Pacific-slope flycatcher (<i>Empidonax difficilis</i>) is one of the many Neotropical migratory songbirds whose populations are steadily declining throughout western North America. This research contributed to the assessment of connectivity in this species by inferring relative breeding origins and habitat selection of juvenile birds that migrate along the Pacific Flyway to the South San Francisco Bay Area in the fall. Feather data collected from July 20 to October 12, 2014 were analyzed for three stable isotopes (&delta;²H, &delta;¹³C, &delta;¹⁵N). Findings revealed that populations migrated sequentially from western regions throughout expected breeding latitudes, with early season migrants most likely coming from the more southern, warmer, and dryer regions of northern California, Oregon, and southern Washington while late season migrants had probable origins in the more northern, cooler, and wetter regions of northern Washington and southwestern British Columbia. This study provided new information on the annual cycle and migratory timing of Pacific-slope flycatchers, and lays the foundation for future assessments of migratory connectivity of this species.</p><p>

Growth plays a key role in regulating ecological and population dynamics. Life history characteristics such as age at maturity, fecundity and age and size at migration are tightly linked to growth rate. In addition, size can often determine survival and individual breeding success. To fully understand the process of growth it is important to understand the mechanisms that drive growth rates. In Atlantic salmon, growth is critical in determining life history pathways. Models to estimate growth could be useful in the broader context of predicting population dynamics. In this dissertation I investigate the growth process in juvenile Atlantic salmon (Salmo salar). I first used basic modeling approaches and data on individually tagged salmon to investigate the assumptions of different growth metrics. I demonstrate the size-dependency in certain growth metrics when assumptions are violated. Next, I assessed the efficacy of linear mixed effects models in modeling length-weight relationships from longitudinal data. I show that combining a random effects approach with third order polynomials can be an effective way to model length-weight relationships with mark-recapture data. I extend this hierarchical modeling approach to develop a Bayesian growth model. With limited assumptions, I derive a relatively simple discrete time model from von Bertalanffy growth that includes a nonparametric seasonal growth function. The linear dynamics of this model allow for efficient estimation of parameters in a Bayesian framework. Finally, I investigated the role of life history in driving compensatory growth patterns in immature Atlantic salmon. This analysis demonstrates the importance of considering life history as a mechanism in compensatory growth. Information provided in this dissertation will help provide ecologists with statistical tools to estimate growth rates, estimate length-weight relationships, and forecast growth from mark-recapture data. In addition, comparisons of seasonal growth within and among life history groups and within and among tributaries should make a valuable contribution to the important literature on growth in Atlantic salmon.

Indonesia has one of the highest diversities of plants and animals in the world and nine of the eleven felid species present in Southeast Asia are found in Indonesia. Yet, Indonesia now leads the world in the number of threatened and endangered mammal and bird species, with new species constantly added to the list. The biggest factor driving the disappearance of wildlife in Indonesia is large-scale habitat loss and degradation. The country is losing its forests at the fastest rate of any nation in the world. In Sumatra alone, nearly 3.1 million hectares of forest were lost in the past decade, and lowland forests have all but disappeared. In the face of continued habitat loss and fragmentation, and a continually increasing human population, it is becoming increasingly apparent that we have to gain some knowledge of these species on Sumatra in order to create effective conservation initiatives, else we risk losing them for good. The present project was initiated to gain such information on small felids in Sumatra. There were three elements to our study: camera trapping, live trapping, and an analysis of human-felid conflict. The camera trapping portion of our study allowed the examination of the distribution, habitat preferences, and activity patterns of small felids on Sumatra. This is the first such information on these species from anywhere in their range and is invaluable to managers as they prioritize habitats for conservation. Our study was the first to attempt live trapping and collaring of small felid species in Sumatra, and one of a very few which had been conducted in the tropical forests of Asia. We were able to capture and collar the first golden cat ever collared in Indonesia, and only the third in the world. The information gained from tracking her movement once again provides invaluable information on the ecology of this species in Sumatra. Finally, we conducted surveys of human-small felid conflict around BBSNP. Prior to our study, human conflict with small felids was not thought to be a major factor in their conservation in Southeast Asia because it was rarely reported to governmental officials. Our study is the first in Southeast Asia to characterize this conflict and its effect on the conservation of small felids in Sumatra. We also assessed the efficacy of simple education and mitigation techniques in reducing conflict, creating a successful model that can be replicated throughout the species range. Overall, this study provides valuable knowledge on the Sunda clouded leopard, the Asiatic golden cat, the marbled cat, and the leopard cat, generating information which may be used for their more effective conservation in Sumatra.

Thesis (M. Phil.)--University of Hong Kong, 1999. / Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 1998. / Includes bibliographical references (leaves 305-327).

<p> Efforts to document current wild bee faunas are imperative as evidence of changes in local abundance, geographical range, and species diversity among many taxa accumulates. These changes and declines have led to an intensified effort to survey wild bees in representative habitats throughout North America. The objective of this study was to characterize the wild bee fauna of one such coastal habitat in Connecticut, USA, specifically to examine marsh, dune, and coastal scrub bee communities.</p><p> Biweekly surveys were conducted at Grass Island Preserve (Guilford, CT) over a two-year period (2011-2012) using pan traps and effort-based (timed) net collecting. A total of 3929 individual bees were collected, representing five families, 18 genera and 80 species. The total number of species collected represents approximately 23% of the known Connecticut bee fauna. Three species -<i>Hylaeus illinoisensis</i> (Robertson); <i>Hylaeus</i> aff. <i>nelumbonis</i> (undescribed); <i>Lasioglossum michiganense </i> (Mitchell) - are newly recorded for Connecticut. Species accumulation curves constructed for all sub-habitats indicated that bee diversity was steadily increasing over the sample period. No asymptote in accumulation curves were observed at any site.</p>