Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Más filtros










Intervalo de año de publicación
1.
Ecology ; 101(11): e03115, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32700802

RESUMEN

Biological invasion is one of the main threats to native biodiversity. For a species to become invasive, it must be voluntarily or involuntarily introduced by humans into a nonnative habitat. Mammals were among first taxa to be introduced worldwide for game, meat, and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in the southeast United States) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g., Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly because of uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species Callithrix aurita, Callithrix flaviceps, Callithrix geoffroyi, Callithrix jacchus, Callithrix kuhlii, Callithrix penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when using the data in publications. We also request that researchers and teachers inform us on how they are using the data.


Asunto(s)
Especies Introducidas , Mamíferos , Animales , Argentina , Biodiversidad , Bovinos , Chile , Perros , Florida , México
2.
Ecology ; 100(12): e02861, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31380568

RESUMEN

Habitat destruction is the single greatest anthropogenic threat to biodiversity. Decades of research on this issue have led to the accumulation of hundreds of data sets comparing species assemblages in larger, intact, habitats to smaller, more fragmented, habitats. Despite this, little synthesis or consensus has been achieved, primarily because of non-standardized sampling methodology and analyses of notoriously scale-dependent response variables (i.e., species richness). To be able to compare and contrast the results of habitat fragmentation on species' assemblages, it is necessary to have the underlying data on species abundances and sampling intensity, so that standardization can be achieved. To accomplish this, we systematically searched the literature for studies where abundances of species in assemblages (of any taxa) were sampled from many habitat patches that varied in size. From these, we extracted data from several studies, and contacted authors of studies where appropriate data were collected but not published, giving us 117 studies that compared species assemblages among habitat fragments that varied in area. Less than one-half (41) of studies came from tropical forests of Central and South America, but there were many studies from temperate forests and grasslands from all continents except Antarctica. Fifty-four of the studies were on invertebrates (mostly insects), but there were several studies on plants (15), birds (16), mammals (19), and reptiles and amphibians (13). We also collected qualitative information on the length of time since fragmentation. With data on total and relative abundances (and identities) of species, sampling effort, and affiliated meta-data about the study sites, these data can be used to more definitively test hypotheses about the role of habitat fragmentation in altering patterns of biodiversity. There are no copyright restrictions. Please cite this data paper and the associated Dryad data set if the data are used in publications.

3.
Ecology ; 100(7): e02663, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31013542

RESUMEN

Xenarthrans-anteaters, sloths, and armadillos-have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths. Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the southern United States, Mexico, and Caribbean countries at the northern portion of the Neotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n = 5,941), and Cyclopes sp. have the fewest (n = 240). The armadillo species with the most data is Dasypus novemcinctus (n = 11,588), and the fewest data are recorded for Calyptophractus retusus (n = 33). With regard to sloth species, Bradypus variegatus has the most records (n = 962), and Bradypus pygmaeus has the fewest (n = 12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans data set. Please cite this data paper when using its data in publications. We also request that researchers and teachers inform us of how they are using these data.

4.
Nat Commun ; 5: 5037, 2014 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-25289858

RESUMEN

Tropical forests play an important role in the global carbon cycle, as they store a large amount of carbon (C). Tropical forest deforestation has been identified as a major source of CO2 emissions, though biomass loss due to fragmentation--the creation of additional forest edges--has been largely overlooked as an additional CO2 source. Here, through the combination of remote sensing and knowledge on ecological processes, we present long-term carbon loss estimates due to fragmentation of Neotropical forests: within 10 years the Brazilian Atlantic Forest has lost 69 (±14) Tg C, and the Amazon 599 (±120) Tg C due to fragmentation alone. For all tropical forests, we estimate emissions up to 0.2 Pg C y(-1) or 9 to 24% of the annual global C loss due to deforestation. In conclusion, tropical forest fragmentation increases carbon loss and should be accounted for when attempting to understand the role of vegetation in the global carbon balance.


Asunto(s)
Biomasa , Ciclo del Carbono , Dióxido de Carbono , Bosque Lluvioso , Brasil , Carbono , Conservación de los Recursos Naturales , Ecosistema
5.
Conserv Biol ; 26(6): 1100-11, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23003666

RESUMEN

Theoretical and empirical studies demonstrate that the total amount of forest and the size and connectivity of fragments have nonlinear effects on species survival. We tested how habitat amount and configuration affect understory bird species richness and abundance. We used mist nets (almost 34,000 net hours) to sample birds in 53 Atlantic Forest fragments in southeastern Brazil. Fragments were distributed among 3 10,800-ha landscapes. The remaining forest in these landscapes was below (10% forest cover), similar to (30%), and above (50%) the theoretical fragmentation threshold (approximately 30%) below which the effects of fragmentation should be intensified. Species-richness estimates were significantly higher (F= 3715, p = 0.00) where 50% of the forest remained, which suggests a species occurrence threshold of 30-50% forest, which is higher than usually occurs (<30%). Relations between forest cover and species richness differed depending on species sensitivity to forest conversion and fragmentation. For less sensitive species, species richness decreased as forest cover increased, whereas for highly sensitive species the opposite occurred. For sensitive species, species richness and the amount of forest cover were positively related, particularly when forest cover was 30-50%. Fragment size and connectivity were related to species richness and abundance in all landscapes, not just below the 30% threshold. Where 10% of the forest remained, fragment size was more related to species richness and abundance than connectivity. However, the relation between connectivity and species richness and abundance was stronger where 30% of the landscape was forested. Where 50% of the landscape was forested, fragment size and connectivity were both related to species richness and abundance. Our results demonstrated a rapid loss of species at relatively high levels of forest cover (30-50%). Highly sensitive species were 3-4 times more common above the 30-50% threshold than below it; however, our results do not support a unique fragmentation threshold.


Asunto(s)
Biodiversidad , Aves/fisiología , Conservación de los Recursos Naturales , Ecosistema , Animales , Brasil
6.
Biota neotrop. (Online, Ed. port.) ; 6(2): 0-0, 2006. graf, tab
Artículo en Portugués | LILACS | ID: lil-447596

RESUMEN

Um total de 198 espécies de aves foi registrado na Reserva Florestal do Morro Grande. O levantamento foi realizado entre os anos de 2001 e 2003, utilizando-se métodos de amostragem qualitativos e quantitativos (redes de neblina e pontos fixos). O número de espécies registrado através dos métodos quantitativos foi menor do que o número total de aves presentes na Reserva, sendo 98 espécies registradas nos pontos fixos e 46 nas redes de neblina. Apesar das diferenças, os dois métodos se mostraram eficientes na detecção de padrões de distribuição das aves. Existe uma grande heterogeneidade da avifauna na Reserva, sendo que as diferenças mais marcantes são entre os trechos de matas primárias e secundárias. As matas primárias são mais ricas e apresentam muitas espécies exclusivas. No entanto, mesmo entre os trechos de mata secundária também existem diferenças. Apesar de ser uma grande área de mata contígua às matas da Serra de Paranapiacaba, muitas aves parecem já ter desaparecido da Reserva, como as sensíveis à caça e os frugívoros de dossel. Mesmo assim a Reserva do Morro Grande abriga uma alta diversidade de espécies, com muitas aves endêmicas e ameaçadas. A manutenção e recuperação de suas matas representam importantes ações para a conservação das aves da Mata Atlântica.


A total of 198 bird species was recorded in the Morro Grande Forest Reserve. The survey was conducted between 2001 and 2003 using qualitative and quantitative (mist-nets and point counts) methods. The number of species recorded with the quantitative methods was lower if compared with the total number of species registered in the reserve, with 98 species recorded with point counts and 46 captured with mist nets. In spite of this difference, both methods detected similar patterns of species distribution, showing a huge heterogeneity in the bird community along the reserve, with the main differences between the mature forest, richer and with several exclusive species, and secondary forests. However, even among secondary forest plots differences could be seen. Besides the large size of the Reserve and the fact that it is well linked with the continuous forest of the Serra de Paranapiacaba, several species have already disappeared from the Reserve. These are mainly species under a high hunting pressure and the large canopy frugivores. Even though, the Morro Grande Reserve harbors a high diversity of species, with several endemic and threatened species. The conservation and restoration of Morro Grande forests represent important actions for bird conservation in the Atlantic forest.


Asunto(s)
Aves/clasificación , Aves/crecimiento & desarrollo , Fauna/análisis , Fauna/clasificación , Fauna/efectos adversos , Flora/análisis , Flora/efectos adversos
7.
Artículo en Portugués | LILACS | ID: lil-447599

RESUMEN

Os levantamentos biológicos realizados nos últimos cinco anos na Reserva Florestal do Morro Grande (RFMG) permitiram inventariar mais de 13.000 indivíduos pertencentes a 673 espécies de árvores, mamíferos não-voadores, aves, répteis, anuros e aranhas orbitelas. A comparação dos dados obtidos revela padrões biológicos consistentes que levam a quatro conclusões principais: i) a RFMG se situa numa condição de transição, recebendo influências das florestas ombrófilas densas e mistas, das estacionais e até do cerrado; ii) todos os grupos taxonômicos estudados apresentam diferenças significativas na riqueza e/ou na composição de espécies quando comparadas as florestas em estádios sucessionais intermediários/avançados de sucessão (80-90 anos após corte raso) e a floresta madura, mais antiga (onde houve apenas corte seletivo), o que deve contribuir para um aumento da diversidade gama da RFMG, uma vez que esta é um complexo mosaico de vegetação em diferentes estádios sucessionais; iii) dado, em parte, aos dois fatores anteriores, a RFMG apresenta um padrão, consistente para diferentes grupos taxonômicos, de elevada riqueza de espécies quando comparada com outras áreas de Floresta Atlântica; iv) por sua localização numa matriz de alta densidade populacional humana, a RFMG vem sofrendo fortes perturbações, em particular devido à caça, extrativismo vegetal predatório e entrada de espécies exóticas e invasoras. A conservação da singular biota da RFMG dependerá do estabelecimento de um plano de manejo que consiga tirar vantagens da proximidade à cidade de São Paulo, em termos de pesquisa científica e projetos educacionais/turísticos, e estabeleça o controle das espécies exóticas, da caça, do extrativismo vegetal e da ocupação inadequada do seu entorno imediato.


In the last five years, the Morro Grande Forest Reserve (MGFR) has been systematically surveyed for different taxonomic groups. More than 13.000 individuals from 673 species of trees, nonvolant small mammals, birds, reptiles, anurans and orb-weaver spiders were sampled. The comparative analysis of the results reveals consistent biodiversity patterns which concern four central issues: i) the MGFR is situated in an ecotone location with the influence from the ombrophilous and mesophilous forests and also from the interior savanna region; ii) all taxonomic groups presented significant differences in species composition and/or richness when medium to old secondary forests (80 to 90 years of regeneration) were compared with old-growth forests (or "mature" forests), where only selective logging were observed; this should contribute to a high gamma diversity, given that the MGFR is a complex mosaic of vegetation in different successional stages; iii) partly due to the two first factors, the MGFR presents a consistent pattern of high species diversity when compared with other areas from the Atlantic Forest region; iv) due to its location in a high human density matrix, the MGFR is being submitted to strong disturbances, mostly related with hunting, vegetation exploitation, and alien species invasion. The conservation of this unique biota will depend on the establishment of a management plan that can take advantage of the proximity from the city of São Paulo, specially for projects of education, tourism and scientific research, and that could control the problems of exotic species, hunting, vegetation exploitation and inappropriate use of the MGFR surrounding.


Asunto(s)
Clasificación , Ecología , Fauna/análisis , Fauna/clasificación , Fauna/efectos adversos , Flora/clasificación , Flora/efectos adversos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...