Estrutura da assembleia e uso do habitat por aves na ecoregi?o da Savana Uruguaia : campos semi-naturais vs. campos de soja

Made available in DSpace on 2015-04-14T13:09:47Z (GMT). No. of bitstreams: 1 458917.pdf: 1917825 bytes, checksum: 2ca6f58d7f644c84a939a28ad578855d (MD5) Previous issue date: 2014-02-28The Uruguayan savanna ecoregion has been affected by land use changes, particularly livestock production and monocultures, such as soybean. As consequence, the habitat quality and the avian assemblages in the region are also being affected, and if we are to protect this habitat and its bird species, studies that generate information that can be used for conservation interventions in the region are essential. We sampled bird species in semi-natural grassland and soybean sites with grassland patches, in Rio Grande do Sul and Uruguay, between 2010 and 2012. In two chapters we evaluated (1) the differences in species richness, density and composition of the avian assemblage in semi-natural grasslands and soybean fields, and (2) the patterns of habitat use by grassland birds, through assessment of species richness and abundance. In the first chapter, we found that soybean fields have the lower species richness. Moreover, species considered as grassland specialists had the greatest value of density in semi-natural grassland sites, and species that are common and habitat generalists were more abundant in the soybean fields. Turning to species composition, our results demonstrated that the types of land use were clearly separated. Among the species recorded, five are classified as threatened or near-threatened according to global and/or regional red lists: Rhea americana, Athene cunicularia and Xolmis dominicanus were recorded in both soya and semi-natural grassland sites, whereas Cistothorus platensis and Xanthopsar flavus were recorded only in semi-natural grassland sites. In the second chapter we analyzed the habitat use of grassland birds by establishing a buffer of 100 meters in each of the 160 points sampled. We calculated the percentage of each land use type in each buffer and found that most of the grassland s bird species analyzed occurred preferentially in sites with large percentage of natural grasslands and/or wet grasslands, and none of them used the soybean fields preferentially. Moreover, more than 60% of the records occurred in the buffers composed by over 90% of natural grassland, and the same pattern was found for the total number of individuals of all bird species. Based on our results, we can conclude that the natural grassland sites are important for the maintenance of the avian assemblage in the region. For the conservation of the grasslands in the region, some important measures are needed, such as 1) control on agricultural management practices (e.g. maintain patches of grasslands in the soybean fields), and 2) development of policies combining agriculture production and conservation of biodiversity.A ecoregi?o da Savana Uruguaia vem sendo constantemente alterada, principalmente quanto ao uso do solo para implanta??o de pastagens e agricultura intensiva. Consequentemente, a qualidade dos habitats e as popula??es de aves tamb?m s?o afetadas. Estudos que gerem informa??es sobre como a densidade das esp?cies varia em ambientes alterados, e que possam proporcionar a??es de conserva??o das ?reas naturais s?o necess?rios. Entre 2010 e 2012 amostramos as esp?cies de aves, atrav?s de pontos de contagem, em ?reas de campos semi-naturais e de cultivos de soja com manchas de campos, no Rio Grande do Sul e no Uruguai. Avaliamos, em dois cap?tulos, (1) as diferen?as na riqueza, densidade e composi??o das assembleias de aves nestes dois tipos de uso do solo e (2) os padr?es de uso do habitat pelas aves campestres atrav?s da avalia??o da riqueza e abund?ncia das mesmas nestes diferentes ambientes. Com refer?ncia ao primeiro cap?tulo, os cultivos de soja apresentaram menor riqueza de esp?cies do que os campos semi-naturais. O mesmo ocorreu com a densidade das esp?cies, sendo que esp?cies consideradas mais especialistas apresentaram os maiores valores de densidade em ?reas de campo semi-natural e esp?cies mais comuns e generalistas foram abundantes na soja. Quanto ? composi??o de esp?cies, os tipos de uso do solo foram claramente separados. Cinco das esp?cies registradas s?o consideradas amea?adas ou quase amea?adas global e/ou regionalmente - Rhea americana, Athene cunicularia e Xolmis dominicanus foram registradas tanto nas ?reas de soja quanto nas de campos semi-naturais, j? Cistothorus platensis e Xanthopsar flavus foram registradas apenas nos campos semi-naturais). Quanto ao segundo cap?tulo, estabelecemos um buffer de 100 metros para cada um dos 160 pontos amostrados, e calculamos a porcentagem de cada tipo de uso do solo nos tamp?es, em cada ponto. Dentre as esp?cies de aves campestres analisadas, a maioria delas ocorreu preferencialmente em campos naturais e/ou campos naturais ?midos, e nenhuma usou primeiramente as ?reas de soja. Al?m disso, mais de 60% dos registros de ocorr?ncia e do n?mero total de indiv?duos destas aves foram registrados nos buffers compostos por mais de 90% de campo natural. A partir destes resultados, conclu?mos o qu?o importantes s?o as ?reas de campo natural para a manuten??o da assembleia de aves. Para a conserva??o dessas esp?cies, por?m, s?o necess?rias algumas medidas importantes dentre as quais podemos destacar: 1) pr?ticas de manejo (por exemplo, a manuten??o de manchas de campo entre os cultivos de soja) e 2) pol?ticas que aliem a produ??o da agricultura e a conserva??o da biodiversidade. Al?m disso, ? importante entender a resposta das diferentes esp?cies de aves frente ?s altera??es do habitat que est?o acontecendo na regi?o

Comunidade de aves em ?reas campestres degradadas por cultivos, em processo de restaura??o no bioma pampa, sul do Brasil

Submitted by PPG Ecologia e Evolu??o da Biodiversidade ([email protected]) on 2019-05-07T17:08:33Z No. of bitstreams: 1 Tese_Thaiane WS_Final.pdf: 1664644 bytes, checksum: dc9000f2642a50efdcfbac0d72405f2d (MD5)Approved for entry into archive by Sheila Dias ([email protected]) on 2019-06-04T14:30:09Z (GMT) No. of bitstreams: 1 Tese_Thaiane WS_Final.pdf: 1664644 bytes, checksum: dc9000f2642a50efdcfbac0d72405f2d (MD5)Made available in DSpace on 2019-06-04T14:48:54Z (GMT). No. of bitstreams: 1 Tese_Thaiane WS_Final.pdf: 1664644 bytes, checksum: dc9000f2642a50efdcfbac0d72405f2d (MD5) Previous issue date: 2019-03-08Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPESBird community in degraded grassland areas by crops, in restoration process in the Pampas biome, south of Brazil. Conversion of natural habitats due to other land uses has focused on ecological restoration, which is aimed to recover degraded ecosystems. Degradation of native habitats also occur in Pampas biome grasslands in Rio Grande do Sul, which comprise 63% of its area and much of its use is destined to agriculture. The objectives of this study were evaluate the structure and composition of the bird communities in passive and active restoration sites of southern Brazil. We also relate them to vegetation variables, and verify the influence of the remnats grasslands of the landscape surrounding the restoration sites. This is the first study of restoration evaluating the bird community realized in these grasslands and in the southeastern South America. Four passive restoration sites and one active which previously had crops were compared to reference areas, i.e. native grasslands. Bird communities were sampled from 2015 to 2017 in point counts of 5 min and 100-m radius. The vegetation variables ? height, degree of visual obstruction and soil cover ? were surveyed through five plots at each point count of birds. We used community analysis packages from R software for the estatistical analyzes, and QuantumGIS for the landscape analyzes. We did not found significant differences in species richness, abundance and composition of bird communities between passive restoration and reference areas, and the number of bird species associated to grasslands were also similar. Seven species responded significantly to the grassland type, survey year, vegetation height, low grasses and/or herbs presence. In addition, eight species recorded are globally or regionally threatened, three of them exclusive to the restoration sites. In the active restoration site, after three consecutive years of monitoring, bird species richness and abundance were higher than the reference area, and species composition also differed in both sites. Six vegetation attributes were different between active restoration and reference area, but in the third year of monitoring grasses and herbaceous became more similar to the native grassland. As for landscape analysis, we found species richness, abundance and occurrence of eight species analyzed individually did not show significant relationship with the amount of the native grasslands remnants surrounding the restoration sites. With caution to extrapolate the results due to the maximum number of replicates that were possible, it was possible to conclude that both passive and active restoration can be used for the bird conservation, since they seem to provide suitable habitat structure for the grassland birds. It is also important consider the surrounding landscape matrix, which can influence the restoration process. Futher studies involving the restoration of degraded habitats and long-term efforts are recommended, evaluating not only plants as tradicionally accomplished, but also animals, providing more consistent and applicable, as well as complementary information.A convers?o dos ambientes naturais devido a outros usos da terra tem dado enfoque ? restaura??o ecol?gica, que se destina a recuperar ecossistemas degradados. A degrada??o de terras nativas n?o ? diferente para os campos do bioma Pampa, no Rio Grande do Sul, que compreendem 63% da sua ?rea e grande parte do seu uso ? destinado ? agropecu?ria. Os objetivos deste estudo foram avaliar a estrutura e composi??o das comunidades de aves em ?reas de restaura??o passiva e ativa em campos do sul do Brasil, relacionando-as a vari?veis da vegeta??o e verificando a influ?ncia dos remanescentes campestres do entorno das paisagens em restaura??o. Este ? o primeiro estudo de restaura??o avaliando a comunidade de aves realizado nestes campos e nos do sudeste da Am?rica do Sul. Quatro ?reas de restaura??o passiva e uma de ativa, que anteriormente tinham cultivos, foram comparadas a ?reas de refer?ncia, ou seja, campos nativos. As comunidades de aves foram amostradas de 2015 a 2017, atrav?s de pontos de contagem com raio de 100 m e dura??o de 5 min. As vari?veis da vegeta??o ? altura, grau de obstru??o lateral e cobertura do solo ? foram amostradas atrav?s de cinco parcelas em cada ponto de contagem das aves. Utilizou-se pacotes de an?lises de comunidade do programa R para as an?lises estat?sticas e o programa QuantumGIS para as an?lises de paisagem. N?o foram encontradas diferen?as significativas na riqueza de esp?cies, abund?ncia ou composi??o das comunidades de aves entre restaura??o passiva e ?reas de refer?ncia, e o n?mero de esp?cies de aves associadas ao campo tamb?m foi similar. Sete esp?cies responderam significativamente ao tipo de campo, ano de amostragem, altura da vegeta??o, gram?neas baixas e/ou presen?a de herb?ceas. Al?m disso, oito esp?cies registradas est?o global ou regionalmente amea?adas de extin??o, sendo tr?s delas exclusivas das ?reas de restaura??o. J? na ?rea de restaura??o ativa, depois de tr?s anos consecutivos de monitoramento, a riqueza de esp?cies de aves e a abund?ncia foram maiores do que a ?rea de refer?ncia, e a composi??o de esp?cies tamb?m diferiu em ambas as ?reas. Seis atributos da vegeta??o foram diferentes entre restaura??o ativa e a ?rea de refer?ncia, mas no terceiro ano de monitoramento as gram?neas e as herb?ceas se tornaram mais similares ao campo nativo. Quanto ? an?lise de paisagem, encontramos que a riqueza de esp?cies, a abund?ncia e a ocorr?ncia de oito esp?cies analisadas individualmente n?o apresentaram uma rela??o significativa com a quantidade de remanescentes de campo nativo do entorno das ?reas em restaura??o. Com cautela para a extrapola??o dos resultados devido ao n?mero m?ximo de r?plicas que foram poss?veis, foi permitido concluir que tanto a restaura??o passiva quanto a restaura??o ativa podem ser utilizadas para a conserva??o das aves campestres, pois parecem fornecer estrutura do habitat adequado para as aves especialistas de campo. Tamb?m ? importante levar em considera??o a matriz da paisagem do entorno, a qual pode influenciar no processo de restaura??o. ? recomendado mais estudos envolvendo a restaura??o de ambientes degradados e esfor?os de longo prazo, avaliando n?o apenas plantas como tradicionalmente realizado, mas tamb?m animais, fornecendo informa??es mais consistentes e aplic?veis, al?m de complementares

Bird diversity-environment relationships in urban parks and cemeteries of the Neotropics during breeding and non-breeding seasons

Background Urbanization will increase in the next decades, causing the loss of green areas and bird diversity within cities. There is a lack of studies at a continental scale analyzing the relationship between urban green areas, such as parks and cemeteries, and bird species richness in the Neotropical region. Bird diversity-environment relationships in urban parks and cemeteries may be influenced by latitudinal gradients or species-area relationships. However, the seasonal variation of species diversity- environment has not been analyzed at a continental scale in the Neotropics. Methods Bird surveys were conducted in 36 cemeteries and 37 parks within 18 Neotropical cities during non-breeding and breeding seasons. Bird diversity was assessed through Hill numbers, focusing on species richness, the effective number of species derived from Shannon index and the Simpson index. Environmental variables included latitude, altitude, and local scale variables such as area size, habitat diversity and pedestrian traffic. Results Species richness and Shannon diversity were higher during the breeding season, whereas Simpson diversity did not vary between seasons. During both seasons, species richness increased with area size, was negatively related to altitude, and was the highest at 20° latitude. Species richness was also positively related to habitat diversity, pedestrian traffic, and was highest in suburban areas during the non-breeding season. Shannon and Simpson diversity showed significant relationships with habitat diversity and area size during the breeding season. Bird diversity was similar between parks and cemeteries. Discussion Our results showed that urban parks and cemeteries have similar roles in conserving urban bird diversity in Neotropical cities. However, species diversity-environment relations at the continental scale varied between seasons, highlighting the importance of conducting annual studies