• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Monitoring birds and habitat in early-successional sites in Connecticut

Mazzei, Benjamin A 01 January 2009 (has links) (PDF)
Early-successional bird species are showing alarming declines across the Northeast and particularly in New England. Utilizing limited resources to the best advantage of these declining bird species is a vital task for land managers. In 2006 and 2007, I collected bird abundance and habitat information from 87 points in early-successional habitat in Connecticut. The objective of this effort was to evaluate the relationships between the habitat variables collected at a plot using the point intercept method and the associated bird abundance at the plot. A second objective was to compare two different methods of characterizing early-successional habitat in explaining the variance in bird abundance. A plot-based method based on the BBIRD protocol from Montana Cooperative Wildlife Research Unit and the point intercept method were compared. Finally, I designed and created a database written in Microsoft Access which was used to standardize data entry, aid in the sharing of data and to calculate summary statistics to assist habitat managers in making conservation decisions. The habitat variables were grouped according to composition and structure to analyze bird-habitat relationships. Low broadleaved shrubs, broadleaved shrubs, fern/forbs, conifers, broadleaved trees and invasives, as well as average height for shrubs and trees were used for the analysis. Nine focal early-successional species that are showing general trends of decline were chosen from the list of all birds seen or heard. Bird abundance and detectibility covariates were modeled with the habitat variables using N-mixture models (2004). Up to 24% of the variation of the best models (based upon AICc) was explained by the predictors I investigated. Five of the 9 birds showed a positive correlation to a shrub category variable. Fern/forbs, graminoids and invasives were found to exert less influence on the abundance of these scrub-shrub birds. Results indicated that the date of the survey affected the detectibility of only 5 of the species, and vegetation height only affected one of the species. Overall correlations indicate that these nine shrubland dependent species utilize a structurally complex habitat including broadleaved shrubs less 2 meters in height and than 2-5 meters in height and herbaceous forbs and graminoids. Invasive plants were found to be positively correlated to 2 of the 9 species possibly warranting additional work on the affects of these species on early-successional birds. Thirty-one of the total 87 point count points were selected for the comparison between the BBIRD and point intercept method. I choose six focal early-successional species for the analysis: indigo bunting, blue-winged warbler, chestnut-sided warbler, yellow warbler, prairie warbler and the common yellowthroat. The point intercept and BBIRD methods explained on average the same amount of variability in the data, and models from each data set included nearly the same number of variables, on average. Thus, we conclude these two vegetation sampling methodologies were essentially equivalent in summarizing important characteristics of scrub-shrub bird habitats. In the field, the BBIRD method took on average almost twice as long to complete as the point intercept method. Because in this study the two methods were similar in the amount of the bird abundance variance they explained and because the BBIRD method takes substantially longer to complete, I recommend that the point intercept method be considered an acceptable method for managers to use to characterize the relationships between early-successional bird species and their habitat. An important step in the successful conservation of declining early-successional bird species is the creation of database management systems and the coordination and cooperation amongst agencies that can stem from the use of these databases. The database I created ensures standardized data entry for data collected from multiple sites over many years. The database takes this data and can be queried for whatever particular information a manager needs. Percent cover of vegetation and invasives, average height of vegetation, and bird abundance are summarized and graphically displayed by the database. Ease of operation, ability to query and ability to share the information makes this database an important tool in the successful conservation of declining species
2

Vegeta??o colonizadora em uma vo?oroca em Gouveia, MG / Colonizing vegetation in a gully in the municipality of Gouveia, MG

Custodio, Sandra Titon 26 July 2017 (has links)
Na ficha catalogr?fica e resumos consta o t?tulo: "Vegeta??o colonizadora em uma vo?oroca no munic?pio de Gouveia, MG". / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2018-03-28T19:48:31Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) sandra_titon_custodio.pdf: 2043403 bytes, checksum: 42f78410758b9e7d112c05a2080acb88 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-03-29T12:11:49Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) sandra_titon_custodio.pdf: 2043403 bytes, checksum: 42f78410758b9e7d112c05a2080acb88 (MD5) / Made available in DSpace on 2018-03-29T12:11:49Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) sandra_titon_custodio.pdf: 2043403 bytes, checksum: 42f78410758b9e7d112c05a2080acb88 (MD5) Previous issue date: 2017 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O objetivo do presente trabalho foi avaliar o comportamento das comunidades vegetais em ?reas degradadas por processos erosivos do tipo vo?oroca, a fim de auxiliar em programas de recupera??o em ?reas degradadas. O m?todo utilizado para a amostragem foi o da interse??o na linha. A ?rea de estudos foi dividida em tr?s setores, de acordo com o porte da vegeta??o e est?gios dos processos erosivos na parte interna da vo?oroca e os setores divididos em estratos: baixada, encosta oeste e encosta leste. Foram registradas 101 esp?cies, divididas em 74 g?neros e 27 fam?lias bot?nicas. As fam?lias Asteraceae e Melastomataceae e os g?neros Baccharis e Miconia foram os mais representativos e o grupo das Samambaias apresentou maiores ?ndices de Frequ?ncia, Cobertura e Valor de Import?ncia. A ?rea apresentou baixa similaridade flor?stica e alta diversidade de esp?cies. Foram registrados maiores porcentagens de esp?cies com s?ndrome de dispers?o zooc?rica, de h?bito arbustivo e forma de vida faner?fita. A an?lise da vegeta??o permite afimar que a ?rea encontra-se em est?gio de sucess?o secund?ria inicial. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / The objective of the present work was to evaluate the behavior of the plant communities in areas degraded by erosive processes - gully type, in order to assist in recovery programs in degraded areas. The method used for sampling was that of the line-intercept. The study area was divided into three sectors, according to vegetation size and stages of the erosive processes in the inner part of the gully and the sectors divided into strata: lowland, west slope and east slope. There were 101 species, divided into 74 genera and 27 botanical families.The families Asteraceae and Melastomataceae and the genera Baccharis and Miconia were the most representative ones and the group of Ferns presented higher Frequency, Coverage and Significance Indices. The area presented low floristic similarity and high species diversity. Higher percentages of species with zoocoric dispersion syndrome, shrub habit and phanerophytic life form were recorded. The analysis of the vegetation allows to emphasize that the area is in the initial secondary succession stage.

Page generated in 0.0623 seconds