Consulta: subjectFacets:"Diversity index"
Registros recuperados: 8
Data/hora: 16/06/2024 17:28:05

La diversidad y prácticas de manejo de los animales domésticos en la región de la montaña del estado de Guerrero.
Provedor de dados: 32
Autores: López Gordillo, José Antonio.
Se analizó la diversidad de los animales domésticos presentes y las prácticas de manejo en la región de la Montaña del estado de Guerrero. En el estudio se realizaron 207 entrevistas a productores para registrar información de la familia, la  ganadería, los recursos naturales utilizados y las prácticas de manejo. Los datos se analizaron con el paquete estadístico SAS. Se estimaron los estadísticos descriptivos para las variables de las explotaciones y los indicadores de la presencia de los animales domésticos. La función social y productiva de cada especie ganadera se determinó con regresión logística. La población promedio de animales en la explotación estuvo determinada por las aves (18.3), caprinos (14.8), bovinos (12.3), ovinos (9.4), cerdos (6) y...
Palavras-chave: Densidad de ganado; Indice de diversidad; Peso vivo; Regresión logística; Sanidad; Alimentación; Livestock density; Diversity index; Live weight; Logistic regression; Health management; Feeding practices; EDAR; Estrategias para el Desarrollo Agrícola Regional; Maestría Tecnológica; Desarrollo Sostenible de Zonas Indígenas.
Ano: 2010
URL: http://hdl.handle.net/10521/359

Detecting changes in diversity in a fluctuating environment based on simulation of stochastic processes
Provedor de dados: 5
Autores: Diserud, Oh.
In this paper, I present a method developed to detect 'extra', or novel, changes in diversity in a naturally fluctuating environment. When comparing samples in order to evaluate changes in community structure, the sampling procedure will inevitably induce randomness in observed species composition and abundance, so two samples may show considerable differences, even if they come from exactly the same community. Sometimes the effort put into the sampling varies as well, leading to the expectation of a further increase in difference. Finally, if there were a temporal distance between the samples, we would like to correct for variations in species abundance occurring naturally due to fluctuating environmental conditions. The test method presented here...
Tipo: Text
Palavras-chave: Structure des communautés; Diversité; Variance environnementale; Dynamique des populations; Modèle d'abondance d'une espèce; Community structure; Diversity index; Environmental variance; Population dynamics; Species abundance model.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/00322/43345/42881.pdf

Habitat heterogeneity effects on macro- and meiofauna (especially  nematodes) in Punta Francés coral reef (SW Cuban Archipelago)
Provedor de dados: 20
Autores: Armenteros, M.; Ruiz-Abierno, A.; Sosa, Y.; Pérez-García, J. A.
Benthic macrofauna and meiofauna distribution patterns were  described in a tropical coral  reef (Punta Francés, Cuban  Archipelago, Caribbean Sea). Density and main taxa composition for macrofauna and meiofauna and species diversity and  organismal traits for free-living nematodes were compared among four habitats: seagrass bed, sand flat, dead coral and hard  bottom. Strong spatial patterns of distribution across habitats were detected and explained by a complex combination of  habitat features. Signal/noise ratio for macrofauna data of distribution was enough strong to detect changes across habitats  but the sizes of sampling devices were not adequate to represent the real patterns in the nature. Meiofauna patterns of  distribution were driven by the...
Tipo: Journal Contribution
Palavras-chave: Coral reefs; Distribution; Diversity index; Macrofauna.
Ano: 2012
URL: http://hdl.handle.net/1834/4552

Contribution of Wheat Diversity to Total Factor Productivity in China
Provedor de dados: 31
Autores: Jin,   Songqing; Meng,   Erika C.H.; Hu,   Ruifa; Rozelle,   Scott; Huang,   Jikun.
The impact of wheat diversity on the productivity of wheat in China is examined using total factor productivity (TFP) and an instrumental variable approach.  TFP in seven key wheat-producing provinces in China shows significant, though variable, growth for all provinces during the period 1982-1995.  Analysis of the causes of TFP growth tests alternative taxonomies of wheat diversity (named varieties and morphological groups) and three measures of diversity.  The analysis shows significant effects of diversity on TFP with results consistent across taxonomies and measures of diversity.  Further decomposition of the estimation results confirms the relative magnitude of impact of wheat diversity on TFP growth.
Tipo: Journal Article
Palavras-chave: Agricultural productivity; China; Crop diversity; Diversity index; Total factor productivity; Wheat; Crop Production/Industries; Production Economics.
Ano: 2008
URL: http://purl.umn.edu/46555

Definitions of Biodiversity and Measures of Its Value
Provedor de dados: 31
Autores: Simpson,   R. David.
The destruction of natural habitats has prompted concerns about the loss of biological diversity. Regrettably, however, there is no consensus among either biologists or economists on the most meaningful measures of biodiversity. Fundamentally different definitions are useful in asking fundamentally different questions. Considerable attention has been given to the value of diversity in search models. A measure of "aggregate variability" is appropriate to such models. Values derived from search models tend to be well behaved; they exhibit diminishing returns in diversity. In contrast, a definition of diversity as "relative abundance" is more appropriate to more complex objective functions. Values derived in these models are not necessarily well behaved. The...
Tipo: Working or Discussion Paper
Palavras-chave: Biological diversity; Biodiversity; Diversity index; Abundance; Search; Variability; Consistency; Contingent valuation; Diminishing returns; Increasing returns; Environmental Economics and Policy; D43; D83; Q20.
Ano: 2002
URL: http://purl.umn.edu/10551

Orthoptera assemblages associated with macrophytes of floodplain lakes of the Paraná River
Provedor de dados: 92
Autores: Capello,Soledad; Marchese,Mercedes; De Wysiecki,María L.
Orthoptera assemblages associated with macrophytes of floodplain lakes of the Paraná River. The Orthoptera assemblage composition varies considerably, depending on habitat type. This study examines the spatiotemporal relationship between plant diversity, hydrometric level, environmental variables and the Orthoptera richness and abundance in floodplain lakes connected permanently or temporarily with the main channel of the Paraná River. The grasshoppers were collected fortnightly (April 2006May 2007). A total of 17 species were recorded and classified according to their frequency of occurrence in constant (7), accessory (4), or accidental (6) species. In the two lakes, the greater species richness and abundance was recorded in summer, thereby coinciding...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Acrididae; Aquatic plants; Diversity index; Hydrological level; Insecta; Tettigonidae.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0085-56262013000100010

โครงการความหลากหลายทางชีวภาพของด้วงมูลสัตว์ในพื้นที่เขื่อนสิรินธร: รายงานวิจัยฉบับสมบูรณ์
Provedor de dados: 106
Autores: Yupa Hanboonsong.
Diversity of dung beetles was studied from 3 different forest sites from Sirinthorn Dam area in Unbonrachathanee province. A total of forty five pig dung baited traps (fifteen traps/site) were used to trap dung beetles from the three studied sites per time. Data were collected five times between January – September 2011. A total of  8,763 dung beetle individuals was found. Among those 7,130 was diurnal beetle and 1,633 was nocturnal beetle. A total of 68 species from 7 genera as Aphodius, Caccobius,  Catharsius, Copris, Paragymnopleurus, Synapsis and Onthophagus. The genus Onthophagus was the most abundant with 56 species. The Shannon-Wiener diversity index (H’) of diurnal and nocturnal dung beetle was highest at the first forest site of savanna mixed...
Tipo: PhysicalObject
Palavras-chave: Diversity index; Dung beetle; Genetic conservation; Sirinthorn dam; ด้วงมูลสัตว์; ดัชนีความหลากหลาย; การอนุรักษ์พันธุกรรม; ความหลากหลายทางชีวภาพ; ชนิด; จำนวนประชากร; เขื่อนสิรินธร.
Ano: 2011
URL: http://anchan.lib.ku.ac.th/agnet/handle/001/5344

ความหลากหลายและความสัมพันธ์ของอาร์โทรพอดส์ในข้าวโพดหวาน
Provedor de dados: 106
Autores: Sangkhae Nawanich; Pojjanee Supamongkol; Wiboon Chongrattanameteekul.
Study on diversity of arthropods in sweet corn was carried out at the National Corn and Sorghum Research Center to determine the diversity and abundance of arthropods in dry season during January-March 2009 and March-May 2009. 210 sample plants were observed by using stratified random sampling technique and data was recorded by visual count method. The species/families/groups and number of arthropods were recorded 4 times at vegetative stage and 3 times at reproductive stage on both crops. Diversity of arthropods was analyzed by Shannon-Wiener diversity index. The results revealed that in the first crop, 34 species/families/groups of arthropod were found and the highest number of arthropods (3,486) was found in at the 6th observation however it also showed...
Palavras-chave: Sweet corn; Arthropod; Diversity index; Relationship; ข้าวโพดหวาน; อาร์โทรพอดส์; ดัชนีความหลากหลาย; ความชุกชุม; ความสัมพันธ์; ศัตรูธรรมชาติ; ปัจจัยสภาพแวดล้อม; ฤดูกาล.
Ano: 2010
URL: http://anchan.lib.ku.ac.th/agnet/handle/001/4684