Resumo: Plantas trepadeiras são componentes característicos das florestas tropicais e contribuem significativamente com a diversidade taxonômica. Além disso, desempenham papel estrutural e ecológico essencial para a manutenção dessas florestas. Áreas perturbadas podem ser locais ideais para a proliferação excessiva de trepadeiras, prejudicando os processos de regeneração natural. O objetivo geral deste estudo foi a caracterização florística e estrutural de comunidades de trepadeiras inseridas em dois fragmentos de floresta estacional semidecidual, sendo um com indicadores de perturbação (município de União Paulista, SP) e o outro considerado conservado (município de Matão, SP). Por meio do método de parcelas, em 1 ha, foram amostradas 3278 trepadeiras. Os 1101 indivíduos identificados no fragmento de Matão foram distribuídos em 19 famílias, 43 gêneros e 65 espécies; as famílias mais ricas em espécies foram Bignoniaceae (17), Sapindaceae (10 ), Malpighiaceae (9) e Apocynaceae (7). Os 1544 indivíduos identificados do fragmento de União Paulista distribuíram-se em 15 famílias, 38 gêneros e 66 espécies; as famílias mais ricas foram Bignoniaceae (25), Malpighiaceae (10), Fabaceae (7), Apocynaceae (6) e Sapindaceae (6). Em Matão houve maior proporção de trepadeiras preênseis (63,9%) em relação a trepadeiras volúveis (27,9%) e escandentes (8,2%). Já em União Paulista foi verificada proporção similar de indivíduos preênseis (47,8%) e volúveis (48,6%), com menor proporção de trepadeiras escandentes (3,6%). A espécie com maior IVI em Matão foi Melloa quadrivalvis, sendo H'=3,11 nats.ind-¹ e J'=0,75. Em União Paulista, Serjania lethalis apresentou maior IVI, sendo o H'= 3,09 nats.ind-¹ e J'= 0,74. A similaridade de Jaccard foi de 36%, enquanto que de Bray-Curtis foi de 32%. As características constatadas para o fragmento de Matão, como... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Climbing plants are characteristic components of the tropical forest and significantly contribute to the taxonomic diversity. Besides, participate in the structural and ecological role essential for the maintenance of those forests. Disturbed areas can be ideal places for the excessive proliferation of vines, harming the processes of natural regeneration. The aim study was the characterization of structural and floristic communities climbers inserted in two fragments of semideciduous forest, one disturbed (placed in União Paulista, SP) and one undisturbed (placed in Matão, SP). In 100 plots (1ha), were sampled 3278 climbers. The 1101 individuals identified from the Matão fragment were distributed in 19 families, 43 genera and 65 species; the richest families were Bignoniaceae (17), Sapindaceae (10), Malpighiaceae (9) e Apocynaceae (7). The 1544 individuals identified from the União Paulista fragment were distributed into 15 families, 38 genera and 66 species, the richest families were Bignoniaceae (25), Malpighiaceae (10), Fabaceae (7), Apocynaceae (6) e Sapindaceae (6). There were more tendril climbers (63.9%), than stem twiners (27.9%) and branch twiners (8.2%). Whereas, in União Paulista was verified a similar proportion of individuals tendril climbers (47.8%), and stem twiners (48.6%), with a smaller proportion of branch twiners (3.6%). Melloa quadrivalvis presented the highest IVI in Matão, were H'=3.11 and J'=0.75. In União Paulista, Serjania lethalis had the highest IVI, H'= 3.09 and J'= 0.74. The Jaccard's similarity was 36%, while Bray-Curtis's similarity was 32%. The characteristics observed in Matão fragment, like total abundance, proportional balance between climbers and trees abundance, significant amount of individuals with diameter >10 cm, besides the larger total basal area despite the smaller abundance, compared with the disturbed fragment; they... (Complete abstract click electronic access below) / Orientador: Osmar Cavassan / Coorientador: Andréia Alves Rezende / Banca: Anne Ligia Dokkedal Bosqueiro / Banca: Marco Antonio de Assis / Mestre

With increasing pressures on sagebrush steppe ecosystems, the sagebrush defoliating Aroga moth, Aroga websteri Clarke (Lepidoptera: Gelechiidae) has become a critical organism of concern. Despite the cyclic nature of A. websteri outbreaks throughout the Great Basin, there is limited information on the moth’s population dynamics. The goal of this dissertation was to develop effective means of assessing and describing population trends of the Aroga moth across space and time, and potentially promoting biological control of the moth to prevent unnaturally large, prolonged and destructive outbreaks. Field studies were conducted to: 1) monitor and quantify activity of the Aroga moth and its damage to sagebrush across a montane landscape, 2) assess the effects of parasitoid and floral diversity on parasitism of the moth, and 3) develop a degree-day (D) model to describe the phenology of the insect, as well as field populations studied previously. North-facing stands of sagebrush, characterized by low values of solar radiation, appear to be especially suitable local habitats for the Aroga moth. High habitat suitability may result from favorable microclimate, both in its direct effects on the Aroga moth and in indirect effects tied to sagebrush plant community productivity and performance. Parasitoid and floral diversity differed strongly and predictably across space and time, with greatest overall parasitism occurring when three major parasitoid species were present. Field experiments revealed individual species of parasitoids differed substantially and complemented one another in their patterns of attack among local populations of the Aroga moth across the montane landscape. Differing responses to provision of floral resources and methyl salicylate (an herbivore- induced plant volatile) support the general hypothesis that over large scales of space and time, species diversity of natural enemies promotes suppression of insect herbivores. Lastly, degree-day models were developed and least variation among years in (D) phenology resulted with the single-sine method with base temperature of 5C. Years of historical Aroga moth outbreaks had characteristic seasonal patterns of D accumulation that were intermediate and characterized by high precipitation in June and July during late stage larval development. Thus, it appears that periodic outbreaks of the defoliator are due to favorable weather conditions.

Objectives of this study were: (1) to determine the status of the utah prairie dog (Cynomys parvidens, Allen), a rare mammal endemic to southcentral Utah, and (2) to identify habitat factors which limit densities of this species. Seven components of the habitat were studied: barriers, other animals, soil, temperature and precipitation, topography, vegetation, and water. Prior to collection of habitat data, virtually all populations of the species were found by extensive searching and interviewing; the number of animals and the area occupied were determined for each population. Results justified the endangered status of the Utah prairie dog. Area occupied by this prairie dog was reduced by an estimated 87 percent during the past 50 years. During this time, the animals disappeared from 34 localities. Recently, total numbers also were reduced: between 1970 and 1971, the total population dropped from an estimated 8, 600 animals to 5, 700. Only 48 substantial populations existed in 1971. Six other populations were exterminated the preceding year by rodent control. Although the loss of prairie dogs between 1970 and 1871 resulted from rodent control, another loss between 1971 and 1972 resulted from drought. A drought decimated all populations in regions without water. Topographic region, which reflected water available to plants, was more strongly correlated to density of this prairie dog than any other parameter (r20' • 67). The crucial role of water was confirmed by analysis of vegetative parameters. Since grasses, forbs, and shrubs have distinctive water contents, they indicated prairie dog response to plant water. Forb cover, which contains the highest relative water content, was the only type of cover that was positively correlated to the density of these animals. Shrubs, with the lowest water content, were negatively correlated; and grasses, with an intermediate water content, were neutral relative to density. Two other parameters also demonstrated the critical nature of water: the mean number of grasses, forbs, and shrubs, and heterogeneity among plant communities. No other parameters were significant (p :::_. 05) in multiple regression. Together, these explained 75 percent of the variability in abundance of the Utah prairie dog. The mean number of grasses, forbs, and shrubs was negatively correlated with density; coefficients of this parameter probably reflected the time required for prairie dogs to select plant parts with adequate water. On the other hand, heterogeneity among plant communities was positively correlated to density, and indicated emergency sources of plant water. Such water probably allowed prairie dogs to avoid population reductions otherwise associated with drought. The critical nature of plant water is especially meaningful in light of long-range drying trends. The Utah prairie dog's habitat has become progressively drier during the past several thousand years. If these trends continue, the animal may become extinct. However, their possible extinction can be delayed by transplanting animals to sites adjacent to streams or irri[;ated fields. Transplanting also can help solve the secondary problem of rodent control: since prairie clogs are often eradicated on private lands, transplant sites should be controlled by the public. Public lands in southern Utah usually contain little water; therefore, purchase of certain private lands with adequate water for the animals is a key to managing this unique prairie dog.

Wetlands are the most important and valuable ecosystems on Earth. They are called “kidneys of the Earth”. Vegetation change detection is necessary to understand the condition of a wetland and to support ecosystem sustainable management and utilization. It has been a great challenge to estimate vegetation (including bald cypress trees) coverage of the wetland because it is difficult to access directly. Satellite remote sensing technology can be one important feasible method to map and monitor changes of wetland forest vegetation and land cover over large areas. Remote sensing mapping techniques have been applied to detect and map vegetation changes in wetlands. To address spectral mixture issues associated with moderate resolution remote sensing images, many spectral mixture methods have been developed and applied to unmix the mixed pixels in order to accurately map endmembers (e.g., different land cover types and different materials within pixels) fractions or abundance. Of them, Mixture Tuned Matched Filtering (MTMF) is an advanced spectral unmixing method that has attracted many researchers to test it for mapping land cover types including mapping tree species with medium or coarse remote sensing image data. MTMF is a partial unmixing method that suppresses background noise and estimates the subpixel abundance of a single target material. In this study, to understand impacts of anthropogenic (e.g., urbanization) and natural forces/climate change on the bald cypress tree dynamic change, the bald cypress trees cover change in University of South Florida Forest Preserve Area was mapped and analysed by using MTMF tool and multitemporal Landsat imagery over 30 years from 1984 to 2015. To evaluate the MTMF’s performance, a tradition spectral unmixing method, Linear Spectral Unmixing (LSU), was also tested. The experimental results indicate that (1) the bald cypress tree cover percentage in the study area has generally increased during the 30 years from 1984 to 2015, but over the time period from 1994 to 2005, the bald cypress tree cover percentage reduced; (2) MTMF tool outperformed the LSU method in mapping the change of the bald cypress trees over the 30 years to demonstrate its powerful capability; and (3) there potentially exists an impact of human activities on the change of the bald cypress trees although a further quantitative analysis is needed in the future research.

This thesis provides new evidence which contributes to a clearer understanding of the mixing history of the lunar soil, the interactions of cosmic rays with the lunar surface and any temporal and spatial variations in cosmic ray intensity at the lunar surface. The bombardment of the lunar surface by cosmic rays produces secondary neutrons which are thermalised by the lunar soil. These thermal neutrons are captured by trace elements with large neutron capture cross sections such as cadmium, gadolinium and samarium. Measurements by thermal ionisation mass spectrometry of the changes in the isotopic abundances of cadmium, gadolinium and samarium due to neutron capture are presented in this thesis. Evidence is also presented of the first observations of mass fractionation in cadmium in lunar soils.Changes have been observed in samples from the Apollo 14, 16 and 17 missions. In 114 [superscript 114]Cd/[superscript 113]Cd changes of 0.3% to 0.5% have been observed in lunar samples 60501,105, 65701,23 and 72161,73, of 0.4% and 0.8% in [superscript 158]Gd/[superscript 157]Gd in samples 14163,848 and 60501,105 and of 0.8%, 1.2% and 0.06% in [superscript 150]Sm/[superscript 149]Sm in samples 14163,848 and 60501,105 and 74220,125 respectively. This is the first time that neutron capture has been detected in cadmium. Mass fractionation effects of 0.30%, 0.53% and 0.54% per mass unit have been observed in lunar samples 60501,105, 65701,23 and 72161,73, the first cadmium mass fractionation observed in lunar soils. The cause of elemental mass fractionation on the Moon is not yet understood. These new data from cadmium, a volatile element with a large mass range from [superscript 106]Cd to [superscript 116]Cd is a valuable contribution to the debate.Thermal neutrons are captured preferentially at resonance energies of 0.03 eV by [superscript 155]Gd and [superscript 157]Gd, at 0.09 ++ / eV by [superscript 149]Sm and at 0.178 eV by [superscript 113]Cd. A comparison of the changes in [superscript 114]Cd/[superscript 113]Cd, [superscript 156]Gd/[superscript 155]Gd, [superscript 158]Gd/[superscript 157] and [superscript 15O]Sm/[superscript149]Sm due to neutron capture can therefore indicate the relative energies of the neutrons.Previous work has compared changes in [superscript 158]Gd/[superscript 157]Gd and [superscript 150]Sm/[superscript 149]Sm, this work extends the comparison with the new measurements of the changes in 114 [superscript 114]Cd/[superscript 113]Cd, This thesis shows that the intensity of the thermal neutrons peaks at a higher energy than the <0.1 eV assumed by Lingenfelter et al. (1972). The capture rate for gadolinium calculated by Lingenfelter, has been shown to be too high, this thesis shows that if a modified energy spectrum is considered, biased towards higher energies, it will bring the calculated neutron capture rate by gadolinium closer to the measured rates.The concentrations of cadmium, gadolinium and samarium in nine lunar samples have been measured for the first time by high precision isotope dilution mass spectrometry. Cadmium in 10017,341, 14310,615, 15041,188, 15059,240, 60501,105, 65701,23, 72161,73 and 74220,125 is 10.0_+0.2, 1.51_+0.02, 32.8+_0.6, 34.9+_0.3, 112+_2, 68.3_+0.8, 57.0+_0.6 and 300+_7 ppb respectively. Gadolinium concentrations of 21+_7 ppm in 14163,848, 3.26+_0.05 and 5.8_+0.3 ppm in 60501,105, and 8.1+_0.2 and 8.6+_0.1 ppm in 74220,125 are presented. Samarium concentrations of 24.3_+0.4 and 29.8_+0.5 ppm were found in 14163,848, 2.68+_0.04 and 14+2 ppm in 60501,105, and 6.3+_0.1 and 6.8+_0.1 ppm in 74220,125.The concentrations of cadmium, gadolinium and samarium in the seven geochemical reference materials BCR-1, BHVO-1, BIR-1, DNC1, MAG-1, PCC-1 and W-2 are also presented, some measured for the first ++ / time by isotope dilution mass spectrometry.

No description available.

Forestry affects most of the forest-covered land in Sweden. In the landscape, the most common stream type is headwaters, which are important sites for many processes and organisms in both the terrestrial and the aquatic ecosystems. The aim of this study was to investigate how the abundance of benthic invertebrate functional feeding groups in headwater streams develops after clear-cutting and if it also is possible to detect a change in the composition of feeding groups. The study also attempts to determine what factors have an effect on temporal changes in abundance of these groups. For the study, 11 sites in northern Sweden were sampled for benthic invertebrates using a Surber-sampler, and for each site canopy-cover and pH was obtained. Further, the age of the surrounding forest at each was visually assessed and created a 100-year gradient along which temporal changes in abundance of the functional feeding groups were investigated. The results revealed that the total abundance of organisms was the highest short after clear-cutting and afterward decreased to the lowest level in streams with the highest age of surrounding forest. Significant results for the functional feeding groups were found for predators, shredders and scrapers, which also had the highest levels of abundance early after clear-cutting and thereafter decreased. The result shows that clear-cutting, not only changes the fundamental terrestrial conditions, but also has an impact on the abundance of different benthic functional feeding group.

Sustainable management of wildlife populations relies on accurate estimates of population size as harvest recommendations are dependent on estimates of sustainable surplus. Techniques for surveying wild turkey populations in Texas are constrained by land access issues, requiring that new methods be developed for population monitoring. I evaluated a combined approach using patch-occupancy modeling at broad spatial scales and intensive double observer roost surveys at local scales to estimate Rio Grande wild turkey (Meleagris gallapavo intermedia) distribution and abundance. I flew replicated aerial surveys during 2007 and 2008 to evaluate distribution of Rio Grande wild turkeys in the south Texas Coastal Sand Plains. I used a double observer approach to estimate local scale abundance. I used a single observer approach to estimate temporal variation in roost use. Detection probabilities from aerial surveys ranged between 0.24 (SE = 0.031) and 0.30 (SE = 0.083). Spatial parameters that influenced distribution of wild turkeys included size of suitable roosting habitat patches and distance to the nearest suitable roosting habitat. I conducted 100 inter-patch double observer roost counts, with counts ranging between 0 to 183 individuals. Average detection probabilities for observers were ~0.90. Roost level occupancy was ~0.84 with detection probabilities between 0.69 (SE = 0.107) and 0.79 (SE = 0.091). Based on my results, aerial surveys combined with local abundance estimation may be one viable alternative to monitor turkey populations over large spatial scales, by reducing overall survey effort without loss of estimated precision.

The interaction of tick species and the microclimate that they inhabit is a subject that is frequently studied. The known biology of the Gulf Coast tick, Amblyomma maculatum Koch (Acari: Ixodidae), was used to conduct analyses to determine which meteorological factors regulate Gulf Coast tick survivorship in an area of Texas that is known for reduced occurrence of this tick species. Gulf Coast tick collection records, that indicated the collection of a single tick or multiple ticks from one animal or multiple animals at livestock markets, were obtained from the Texas Animal Health Commission. These records were used as an indicator of adult Gulf Coast tick abundance during each year in the 90 county study area and were used as the dependent variable in linear, quadratic, and cubic regression analyses. Independent variables used in these analyses were precipitation and differing drought thresholds during the peak activity time of the four life stages of the Gulf Coast tick and during combined life stage peak activity times. Linear, quadratic, and cubic regression analyses to measure the effect of precipitation during differing peak activity times of the Gulf Coast tick on adult Gulf Coast tick collection records were not statistically significant. These three regression analyses were also used to measure the effect of increasing drought thresholds, measured using a Keetch-Byram Drought Index, on adult Gulf Coast tick collection records. A determination was made that increasing drought thresholds during the peak activity time of differing Gulf Coast tick life stages reduce the number of Gulf Coast tick collection records the following year.

Lesser prairie chicken (Tympanuchus pallidicinctus; LPC) numbers have declined considerably in Texas since the early 1900s. As with other prairie chicken species, reasons for declining ranges and numbers have been attributed primarily to degradation and fragmentation of habitats. Until my study, no telemetry-based research on LPC has been conducted in the Rolling Plains of the Texas Panhandle. I radio-tagged and monitored LPCs in 2001 (spring??winter) and 2002 (spring) at a stable population in a native rangeland landscape (Study Area I) and in a declining population in a fragmented rangeland and agricultural landscape (Study Area II). No significant (P < 0.05) differences in survival were detected for combined study areas between years, or between study areas within years. Ranges and movements, as independent criteria by season, sex, and age classes combined were similar (P > 0.05) for both study areas. Lesser prairie chickens predominately occupied native rangeland cover types (>85%) compared to non-native rangelands at both study areas. Total invertebrate dry mass for all orders differed between native rangeland and Conservation Reserve Program (CRP) sites at Study Area II. Over 32 times more dry mass of invertebrates was collected at the native rangeland site than were collected at the CRP site. Herbaceous cover differed significantly for grasses (P < 0.01), forbs (P < 0.01), and bare ground (P < 0.01), but not for litter (P = 0.43) or woody cover (P = 0.63) between study areas. The similar range sizes, movement distances, and cover use observed for both study areas may provide insight into minimum area requirements for LPCs within the Rolling Plains in the Texas Panhandle.