During the spring seasons of 1967 and 1968 ecological studies were made of nesting Ferruginou.s Hawks (Buteo regalis) in a 325 square mile area in west-central Utah. In the springs of 1967 and 1968 a systematic search was conducted throughout the study area for Ferruginous Hawk nests. When active nests were located they were kept under observation throughout the study. The density of nesting pairs in 1967 and 1968 ranged from 7 to 15.4 square miles per pair. An annual seasonal displacement was exhibited, with Ferruginous Hawks being present in the study area only during the nesting season, which lasted from early March until early September. Nest locations implied a preference to inhabit particular areas. The distance separating neighbors in 1967 and 1968 varied from 2.3 miles to .4 miles. More than ninety percent of the pairs observed attended more than one nest; such supernumerary nests averaged 2.5 per pair. The majority of nests were constructed on the ground. More than half of the nests faced south; only about one-tenth faced north. The typical nest was composed of large sticks, lined with bark , grass, and paper, and had an average diameter of 39 inches, a thickness of 17 inches, a pocket diameter of 14 inches, and a pocket depth of 3 inches. Both members of each pair of hawks were active in nest building, which began in early March. In 1967 thirteen nests produced 20 eggs (1.5 eggs per nest) and 8 young (.67 percent), of which 8 (100 percent) fledged (.67 per nest); in 1968 fourteen nests produced 50 eggs (3.57 eggs per nest) and 33 young (2.36 per nest), of which 28 (85 percent) fledged (2 per nest). Territorial behavior was inconsistent. On occasion each nesting pair was seen to actively defend its territory against other predatory birds; whereas on other occasions intruding raptors met no resistance from the resident pair of Ferruginous Hawks. From 26 eyries, 283 prey individuals were identified. Mammals (92 percent) predominated. The Ord's Kangaroo Rat (Dipodomys ordii) was the most numerous prey species (44 percent), with the Blacktail Jackrabbit (Lepus californicus) being the next most common (30 percent). Birds represented 5 percent of the total prey. Several hunting techniques were exhibited by the hawks. Hunting was usually conducted before sunrise and after sunset each day. Recorded mortality was minimal, with only one dead Ferruginous Hawk observed during the study.

Microfungi were isolated from soil samples by the soil plate method. Soil samples were collected at depths of 0-1", 1-4", and 4-8" both between and beneath the canopy of the dominant vegetation in stands of greasewood, sagebrush, and pinyon-juniper. Salinity, pH, and percent organic matter were measured for each soil sample. A total of 148 strains of fungi representing 141 species and 46 genera were isolated and identified from these alkaline soils, Few strains, including some Aspergilli, occurred only in the more saline greasewood soils, while many strains, including several Penicillia, occurred in both sagebrush and piny-on-juniper soils but were lacking in the greasewood soils. Many strains, including Penicillia, were found primarily in the more organic soils beneath plants, while few strains, including some Aspergilli, were found primarily in soils from between plant cover. Strains of the family Demataceae were found primarily in the surface layers. There was no noticeable difference in the kinds of fungi isolated from the 1-4" and 4-8" layers.

No description available.

No description available.

Reducing apple (Malus x domestica Borkh.) crop load during bloom is a reliable option for increasing fruit quality and return bloom. In this thesis, multiple approaches to improving bloom thinning practices are discussed. The first project analyzed the pollen tube growth of several crabapple cultivars. Previous research had improved the use of bloom thinning chemicals, by coordinating the application timing with the pollen tube growth between pollination and fertilization. However, pollen tube growth rates have only been measured in a few genotypes. In Chapter 2, the pollen tube growth rates of five crabapple cultivars were measured in the styles of 'Fuji', 'Golden Delicious', and 'Pink Lady' flowers, at four temperatures 12, 18, 24 and 30 C. Complex relationships were found among paternal pollen tube growth, maternal cultivar, and temperature. Chapters 3 and 4 describe projects where organically-approved chemicals, including the biofungicide, Regalia, were evaluated for their ability to simultaneously reduce crop load and decrease early season disease infection. These chemicals were applied in conventionally managed orchards (Chapter 3), and in an organically-managed 'Honeycrisp' orchard (Chapter 4). The number of chemicals approved for bloom thinning is limited, especially in the Eastern U.S. where lime sulfur and oil applications are not permitted during bloom. These studies indicate Regalia, applied during bloom, can reduce crop load and provide early season disease control. The research presented in this thesis provides new knowledge that can be incorporated into crop load management practices in both conventional and organic apple orchards. / Master of Science

Thesis (MSc)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: The Greater Cederberg Biodiversity Corridor (GCBC) is a large-scale conservation corridor situated in the south-western region of South Africa. Delineation of the GCBC was largely based on by vegetation data. The relevance of the GCBC for the conservation of the reptilian fauna in the area south of 31°S and west of 21°E is assessed in the present study. This entailed determining the GCBC’s coverage of regional reptile diversity patterns and assessing its potential conservation significance during possible climate induced changes in reptile distributions. Reptile species point distribution data from the preliminary (2007) SARCA (South African Reptile Conservation Assessment) database was used. Under-representation of the Tankwa Karoo in the dataset required a field survey of this region. Additionally, the biogeographical influence of the arid Tankwa Karoo Basin on the distribution of reptiles in the south-western districts of South Africa was investigated. Turnover across the Basin is high, species richness is lower than in surrounding mountainous areas and there are no species endemic to the area. The Tankwa Karoo Basin acts as a dispersal barrier for many reptile species occurring in the surrounding more mesic areas. At the same time, the ranges of a number of typical northern, arid adapted species extend southward along the Tankwa Plains. A number of species range extensions in the region are reported. Patterns of endemism, species richness and turnover were plotted from the point distribution data at quarter and eighth degree square resolution. Extensive sampling bias towards reserves and populated areas is apparent from the reptile species richness plots. This pattern is more pronounced for snakes than lizards. Reptile richness is particularly high along the north-south section of the Cape Fold Mountains and also relatively high along the south-western coast, peaking in the Lambert’s Bay area. The majority of the 20 reptile species endemic to the study area are associated with one of two identified centres of endemism: the Greater Cederberg area, or the narrow coastal zone stretching from the Lambert’s Bay area to the Cape Peninsula. An additional third set of endemics comprised of melanistic forms restricted to a number of different refugia, notably, Landroskop, the Cape Peninsula, Sladanha-Langebaan region, Piketberg Mountains and a confined area along the western section of the Cape Fold Mountains. Species richness and endemism patterns co-vary within the study area. Biotic regions were identified through hierarchical clustering of grid cells according to shared species occurrences. A Northern, Southern, Central and Western biotic region was identified. Classification tree methodology (CART) and Canonical Correspondence Analysis (CCA) were used to characterise defined biotic regions in terms of selected environmental variables. Four sets of species assemblages are described on the basis of these biotic regions – two major and two minor ones. Of the major assemblages the Northern assemblage can be described as an arid zone one and the Southern assemblage as a mesic zone one. The minor Central assemblage, comprising mainly rock-dwelling forms, represent evolutionary leftovers as a result of climate change induces cycles of contraction and expansion of arid and mesic faunas. The other minor one, the West Coast assemblage could be considered a sub-assemblage of the Northern one, with particular adaptation to the coastal climate. Environmental characterisation of the biotic regions reveals that these groupings are supported by an environmental signal. The contiguity of four distinct sets of reptiles, each with its own set of environmental requirements, in this relatively small geographic area clearly indicates that the southwestern region of South Africa is biogeographically complex. The GCBC incorporates the largely coinciding centres of endemism and richness along the West Coast and the greater Cederberg area. Although the centre of endemism for melanistic reptile forms, in the Saldanha-Langebaan area, falls just south of the GCBC boundary, the Corridor fulfils the requirements for effective conservation of reptiles in the area to a large degree. The north-south dispersal pathways provided by the Corridor along the Cape Fold Mountains is believed to be adequate to buffer climate change effects, however there is concern about its ability to contribute to the persistence of the assemblage associated with the narrow coastal zone in the west. / AFRIKAANSE OPSOMMING: Die Groter Cederberg Biodiversiteit Korridor (GCBK) is ‘n grootskaalse bewaringskorridor wat in die suid-westelike deel van Suid-Afrika geleë is. Die grense van GCBK is gebasseer op plantegroei data. In die huidige studie word die betekenis van die GCBK vir die bewaring van die reptiel fauna in die gebied suid van 31°S en wes van 21°O assesseer. Die mate waartoe die GCBK die patrone van reptieldiversiteit in die streek inkorporeer, asook die korridor se potensiaal om voorsiening te maak vir reptiel verspreidingsgebiede wat moontlik as gevolg van potensiële omgewingsverandering kan verskuif. Die beskikbare puntverspreidingsdata van die voorlopige (2007) SARCA (South African Reptile Conservation Assessment) databasis is gebruik. Swak verteenwoordiging van die Tankwa Karoo in die datastel het ‘n veldopname van die gebied genoodsaak. Verder is die biogeografiese invloed van die ariede Tankwa Karoo Kom op die verspreidingspatrone van reptiele in die suid-westelike deel van Suid-Afrika ook ondersoek. Die spesie omset van beide Noord na Suid en Wes na Oos oor die Tankwa is hoog, die spesierykheid is aansienlik laer as in die omringende bergagtige gebiede en daar is geen spesies wat endemies is tot die Tankwa Karoo nie. Die Tankwa Karoo Kom dien as ‘n barieêre teen spreiding vir sommige reptielspesies wat in die omringende gematigde gebiede voorkom. Terselfdertyd reik die verspreidings van ‘n aantal tipiese droogte aangepasde spesies vanuit die noorde suidwaarts langs die Tankwa Vlaktes. Nuwe verspredingsrekords wat ‘n paar spesies se gebiede uitbrei word ook raporteer. Die puntverspreidingsdata is geruik om die patrone van endemisme, spesierykheid en omset op kwart- en agtstegraad resolusie te plot. Spesierykheid kaarte toon ‘n duidelike neiging tot deegliker opnames in reservate en bewoonde gebiede. Hierdie patroon is meer opmerklik vir slange as akkedisse. Reptielrykheid is besonders hoog langs die noord-suid as van die Kaapse Plooiberge en ook relatief hoog langs die suid-wes kus met ‘n maksimum in die Lambertsbaai omgewing. Die meerderheid van die 20 reptielspesies wat endemies is aan die studie area is met een van twee geïdentifiseerde sentrums van endemisme geassosieer: die Groter Cederberg area óf die nou kussone wat vanaf Lambertsbaai tot Kaappunt strek. ‘n Derde stel endemiese spesies wat uit melanistiese vorme bestaan, is beperk tot ‘n aantal refugia, naamlik, Landroskop, Kaappunt, Saldanha- Langebaan omgewing, Piketberg berge en ‘n beperkte area langs die westelike dele van die Kaapse Plooiberge. Spesierykheid en endemisme patrone stem grootliks ooreen binne die studie area. Roosterselle is op grond van gedeelde spesiesamestellings met behulp van ‘n hieragiese groeperingsmetode (Incremental Sum of Squares) gegroepeer. Vier bio-areas, nl. ‘n Noordelike-, Suidelike-, Sentrale en Westelike bio-area is identifiseer. Klassifikasieboom metodologie (Classification and Regression Trees, CART) asook Kanoniese Annalises (Cannonical Correspondence Annalysis, CCA) is gebruik om hierdie geografiese areas in terme van ‘n aantal omgewingsveranderlikes te karakteriseer. Vier spesieversamelings, twee groter en twee kleiner versamelings, is in ooreenstemming met hierdie vier areas geïdentifiseer. Die Noordelike en Suidelike spesieversamelings is die groteres en kan beskryf word as die faunas van onderskeidelik ‘n ariede en gematigde sone. Die kleiner Sentrale versameling bestaan hoofsaaklik uit rots-lewende spesies en mag die evolusionêre oorblyfsels verteenwoordig van ariede en gematigde faunas waarvan die verspreidings herhaaldelik as gevolg van klimaatsveranderingsiklusse uitgebrei en gekrimp het. Die Weskus versameling is ook ‘n kleiner een en kan as ‘n sub-versameling van die Noordelike een beskou word, maar spesifiek tot die kus klimaat aangepas. Die klassifikasie van hierdie bio-areas word ondersteun deur die analiese van die omgewingsveranderlikes. Die feit dat vier kenmerkende versamelings reptiele, elk met sy besondere omgewingsvereistes, in hierdie relatief klein geografiese area ontmoet, dui daarop dat die suid-westelike deel van Suid-Afrika biogeografies kompleks is. Die GCBK inkorporeer die grootliks ooreenstemmende sentrums van endemisme en rykheid wat langs die Weskus en in die groter Cederberg area voorkom. Alhoewel die sentrum van melanistiese endemiese spesies, in die Saldanha-Langebaan omgewing, net buite die grense van die Korridor val, voldoen die GCBK grootliks aan die vereistes vir die effektiewe bewaring van reptiele in die gebied. Die voorsiening van noord-suid verspreidingsweë langs die Kaapse Plooiberge binne die Korridor word beskou as voldoende om die gevolge van klimaatsverandering te buffer. Daarinteen is daar kommer oor die vermoeë van die GCKB om ‘n doeltreffende bydrae te maak tot die voortbestaan van die spesieversameling wat met die nou kussone langs die Weskus geassosieer is.

Tree-ring formation of eastern white-cedar (Thuja occidentalis L.) at a boreal lake in northwestern Quebec, Canada, was monitored using manual band dendrometers to (i) retrace cambial activity phases, (ii) evaluate the effects of flooding on radial growth, and (iii) analyze the relationships with meteorological factors. The daily circumferential activity of four trees at each of two sites, a riparian and an upland site, was recorded during the growing season of 1996, a year with an extreme spring flood. First cambium cell divisions occurred near June 9, followed by a distinct and sustained upward trend in the stem basal area until mid-July that reflected the earlywood formation. The strongly synchronous circumferential activity at both sites suggests no adverse flooding effect on growth of the riparian trees, which is explained by the rapid retreat of the water just before growth initiation in early June. The following month until mid-August was characterized by strong short-term fluctuations caused by alternating drought and rain periods and a slight downward trend of the basal area for six of the eight banded white-cedars. The dendrometers of two trees, the closest to the lake, showed a slight upward trend probably reflecting latewood formation. Pearson correlation with meteorological data indicated that precipitation was positively related to the daily changes in basal area of all trees except during the period of earlywood formation, which probably resulted from the high soil moisture after spring snow-melting. Mean and minimum air humidity were positively related and maximum temperature negatively related to the daily variations in stem circumference during the whole monitoring period, emphasizing the importance of the internal water status on stem size.

Cedrela fissilis Vell. é árvore alta (10 a 30 m) por 40 a 50 cm de diâmetro. Tronco retilíneo com sapopemas pouco desenvolvidas ou ausentes, mas quando atacado pela broca do ponteiro, Hypsipila grandela, é tortuoso. Casca grossa, dura, fissurada, de marrom a pardo - acinzentada. Folhas alternas com 8 a 24 pares de folíolos. Flores actinomorfas, unissexuadas, de 5 a 10 mm de comprimento reunidas em tirsos axilares. Os frutos são cápsulas lenhosas deiscentes de 3 a 10 cm de comprimento, que encerram de 30 a 300 sementes aladas, com até 35 mm de comprimento por 15 mm de largura. A polinização é realizada por insetos, possivelmente mariposas e abelhas e a dispersão de sementes é anemocórica. C. fissilis é uma das espécies arbóreas mais ameaçadas pelo corte seletivo e destruição da Mata Atlântica no centro-sul do Brasil, sua principal área de ocorrência, tornando a conservação dos seus recursos genéticos extremamente ameaçada pela redução populacional que vem sofrendo. Por outro lado, esta espécie tem um grande potencial para produção de madeira de alta qualidade, principalmente em plantios mistos, que estão se tornando economicamente viáveis pela escassez de madeira no mercado nacional e internacional, bem como, está sendo também muito utilizada em projetos de restauração de florestas tropicais. Neste contexto, torna-se fundamental o estudo da diversidade genética das populações remanescentes desta espécie e da estruturação desta diversidade. Este trabalho analisou dez populações de C. fissilis em cinco estados da região centro-sul do Brasil, visando analisar sua estrutura genética e inferir estratégias para sua conservação, bem como estabelecer critérios para a utilização dos recursos genéticos existentes. Foram desenvolvidos nove locos microssatélites para a espécie revelando 130 alelos em todas as populações. A endogamia nas populações foi relativamente baixa. As populações apresentaram diferenciação genética segundo o modelo de isolamento pela distância. As populações tanto da floresta estacional semidecidual como da floresta ombrófila densa apresentaram maior similaridade entre si. A estrutura genética interna de duas populações (Parque Estadual Intervales SP e Parque Estadual do Rio Doce - MG) mostrou uma distribuição aleatória dos genótipos. Já na população da Reserva Florestal do Matão PR, a estruturação espacial foi significativa, revelando uma similaridade genética entre os indivíduos mais próximos (até 30m). Indivíduos jovens e adultos foram analisados em duas populações (Parque Estadual Intervales - SP e Reserva Florestal do Matão PR) revelando uma diversidade gênica semelhante para os dois estádios nas duas populações. No entanto, observa-se uma tendência de aumento da diversidade gênica e diminuição de endogamia nos adultos em relação aos jovens. Estes dados permitem também inferir sobre outras espécies florestais similares, uma vez que não existem dados disponíveis sobre a diversidade genética em grandes regiões geográficas em espécies arbóreas da Mata Atlântica. / Cedrela fissilis Vell. is a high tree (10 a 30 m) with a DBH between 40 and 50 cm. Rectilinear trunk with little developed or absent sapopemas, but when attacked by the Cedar Shoot Borer is crooked. Thick, hard, brown to gray bark. Alternate leaves from 8 to 24 leaflet pairs. Actinomorfic unisexual flowers, from 5 to 10 mm length, produced in groups. Fruits are wood deiscent capsules from 3 to 10 cm length, with 30 to 300 winged seeds, till 35 mm length by 15 mm wide. Pollination is conducted by insects, probably moths and bees and seed dispersion is anemocoric. Cedrela fissilis is one of the most endangered tree species due to the selective logging and destruction of Atlantic Forest in southern-center Brazil, its main distribution region. On the other side, this species has a grate production potential of a high quality wood, mainly in mixed stands, what becomes economically viable because the lack of wood in national and international market, as well as it is being used in restoration projects of tropical forests. Besides these facts, the conservation of genetic resources of this species is very critical by the drastic population reduction that it is suffering. In this context, it becomes very important the study of the genetic diversity of the remnant populations of this species and the structure of this variation. This study analyzed ten natural populations of C. fissilis in five states in the southern-center region of Brazil, aiming to examine their genetic structure and infer strategies for genetic conservation, as well as, establishes criteria to use the genetic resources. Nine microssatellites loci were developed for this species and revealed 130 alleles in all populations. Populations inbreeding was relatively low. Populations presented genetic differentiation following the isolation by distance model. Populations from the seasonal semi deciduous forest, as well as from the evergreen forest presented higher similarity among them. Internal genetic structure of two populations (Intervales State Park SP and Rio Doce State Park - MG) showed a random spatial distribution of genotypes. The population of Matão Forest Reserve PR showed a significant spatial structure, revealing a genetic similarity among near trees (till 30 m). Juveniles and adult plants were analyzed in two populations (Intervales State Park - SP and Matão Forest Reserve PR), showing similar genetic diversity for the two classes in both populations. But, we observe a tendency of increase in genetic diversity and decrease in inbreeding in adult plants in relation to juveniles. These data also allow inferring about other similar tree species, since there is no available data on the genetic diversity of Atlantic Forest tree species in large geographical regions.

Thesis (D. Min.)--New Orleans Baptist Theological Seminary, 1998. / Abstract and vita. Includes bibliographical references (leaves 200-205).

Western larch (Larix occidentalis Nutt.) is an important component of the montane forest in southeastern British Columbia. It grows in cool-temperate (IDF and ICH zones) and boreal climates (MS zone and, occasionally, ESSF zone). Larch is considered a very shade-intolerant species which can tolerate low light (partial shading) only during the seedling stage (the first 5 growing seasons). Typically, it regenerates after fire in the open on seedbeds exposed by burning. However, to what extent it tolerates low light and how various light environments affect its survival and growth is not known. The objective of our study was to determine the variation in survival and growth of western larch seedlings in relation to light availability and site conditions.