4 resultados para species list

em DigitalCommons@University of Nebraska - Lincoln


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In dealing with population estimates, we need to determine first the reason for estimating the population. If we are dealing with a local situation, are we concerned with a local estimate? If we are dealing with a regional problem, are we concerned with a regional estimate? The blackbird problem is chiefly a regional problem, but we need to look at broader horizons than just local or regional situations. Are we dealing with a national problem? Is this problem a year-round one or is it a seasonal problem? We may want to know just purely the number of birds we are dealing with. Another reason for doing population estimates might be to determine the effectiveness of some lethal control method that has been employed. Fortunately, those species with which we are most concerned are those not on the endangered species list at the present time. Many Ohio farmers would like to see the Red-winged Blackbird on the endangered species list, I think, but it is not there. My particular interest in population estimates is to determine if we can develop an early warning system for the agriculturists, so that they can better anticipate the time they can expect damage from birds. A lot of methods have been tried in the past.

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Addition of three species to the list is recommended based on recent literature. (Orcaella brevirostris) has been split into the Irrawaddy dolphin (O. brevirostris) and the Australian snubfin dolphin (O. heinsohni). Sotalia fluviatilis has been split into the riverine tucuxi (S. fluviatilis) and the marine "costero" (S. guianensis). Evidence to support both of these splits is convincing, and we recommend that they be recognized in the list. The existence of the Bryde's-whale-like species described in 2003 as Balaenoptera omurai has been confirmed with additional genetic (nuclear) data. While the species clearly exists, the nomenclature is still unsettled because the genetic identity of the holotype specimen of Balaenoptera edeni has not yet been determined. However, the name B. omurai is gaining wide usage in application to the new species, and we propose that it be used provisionally by the Scientific Committee pending the genetic identification of the B. edeni holotype. We recommend that India be urged to facilitate the identification. We recommend continued use of the name Balaenoptera edeni provisionally for both the "ordinary" large form and the small coastal form, recognizing that further genetic and morphological research may justify recognition of two species: B. brydei and B. edeni. We also recommend that any new specimen be referred to B. omurai only after its mtDNA has been sequenced and found to support the identification.

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The National Collection of Arachnids, Instituto de Biología, Universidad Nacional Autónoma de México (México City) houses 476 chilopod samples, of which 197 are determined to genus and/or species. These are documented here and represent several new state records. Topotypes of eight species of centipedes described by R. V. Chamberlin also documented. Resumen. La Colección Nacional de Arácnidos, del Instituto de Biología de la Universidad Nacional Autónoma de México (Ciudad de México), resguarda 476 muestras de quilópodos, de los que 197 están determinadas a nivel de género y/o especie. Algunas de estas muestras corresponden a nuevos registros estatales. Se documentan los topotipos de ocho especies de ciempiés descritos por R. V. Chamberlin.

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Stabilizing human population size and reducing human-caused impacts on the environment are keys to conserving threatened species (TS). Earth's human population is ~ 7 billion and increasing by ~ 76 million per year. This equates to a human birth-death ratio of 2.35 annually. The 2007 Red List prepared by the International Union for Conservation of Nature and Natural Resources (IUCN) categorized 16,306 species of vertebrates, invertebrates, plants, and other organisms (e.g., lichens, algae) as TS. This is ~ 1 percent of the 1,589,161 species described by IUCN or ~ 0.0033 percent of the believed 5,000,000 total species. Of the IUCN’s described species, vertebrates comprised relatively the most TS listings within respective taxonomic categories (5,742 of 59,811), while invertebrates (2,108 of 1,203,175), plants (8,447 of 297,326), and other species (9 of 28,849) accounted for minor class percentages. Conservation economics comprises microeconomic and macroeconomic principles involving interactions among ecological, environmental, and natural resource economics. A sustainable-growth (steady-state) economy has been posited as instrumental to preserving biological diversity and slowing extinctions in the wild, but few nations endorse this approach. Expanding growth principles characterize most nations' economic policies. To date, statutory fine, captive breeding cost, contingent valuation analysis, hedonic pricing, and travel cost methods are used to value TS in economic research and models. Improved valuation methods of TS are needed for benefit-cost analysis (BCA) of conservation plans. This Chapter provides a review and analysis of: (1) the IUCN status of species, (2) economic principles inherent to sustainable versus growth economies, and (3) methodological issues which hinder effective BCAs of TS conservation.