No abstract

2004. Novel patch Á/matrix interactions: patch width influences matrix use by birds. Á/ Oikos 107: 634 Á/644.This study investigated the influence of the width of patches of native eucalypt forest on bird occurrence in stands of exotic radiata pine (Pinus radiata ) forests that surrounded such patches. Boundaries between eucalypt and pine forests were surveyed to examine bird occurrence and species richness at different distances in the pine matrix from eucalypt forest edges. Birds were counted by the area search method within 0.5 ha quadrats at 32 study sites (where sites spanned the boundaries of pine and eucalypt forests). Data were examined using generalised linear mixed models. Species richness and occurrence of particular species in quadrats located within pine forests decreased with increasing distance from eucalypt patches. This resulted, in part, from the fact that several species found in native patches also use pine plantations as additional foraging areas. Species richness decreased more quickly with distance from eucalypt patches in younger than in older pine stands. The width of native forest patches also influenced bird occurrence in adjacent pine forest matrix. Bird species richness decreased more rapidly in exotic plantations adjacent to wide rather than narrow patches of native forest. To the best of our knowledge, no studies have previously reported that dimensions of patches can influence the use of surrounding matrix. We introduce the term ''halo effect'' for the influence of patch attributes on the differential use of matrix adjacent to native patches. These patterns highlight that conservation efforts in patchy environments should protect not only native patches but also adjacent areas of matrix into which animals extend their home ranges.

SummaryIn the Cerrado of Brazil, the largest Neotropical savanna region, open habitats are suffering an intense process of conversion to pasture and agricultural land. This study evaluated the responses of birds to the thinning of tree and shrub cover in plots of cerrado sensu stricto, the dominant habitat in the region, and examined whether disturbed plots supported bird communities of open natural habitats with similar structure. Birds were censused by point counts in five disturbed sites and in seven preserved patches, with a total of 304 samples of 20 minutes in 68 points. Cleared plots were not suitable for species strongly dependent on trees and shrubs, such as frugivores and most insectivores. Their abundance was associated with the complexity of vegetation structure in these plots. Shrubby pastures held about 120% more species than the traditional cleared ones. Bird communities of pastures showed large differences in relation to those of grasslands with similar structure. Communities of pastures were dominated by a seedeater, the Blue-black Grassquit Volatinia jacarina, and most species were habitat generalist or oportunistic predators, such as raptors and insectivores. Obligate grassland species, like the Grass Wren Cistothorus platensis, Cock-tailed Tyrant Alectrurus tricolor and Black-masked Finch Coryphaspiza melanotis, as well as other abundant species in grasslands, such as Sharp-tailed Grass-tyrant Culicivora caudacuta and Capped Seedeater Sporophila bouvreuil do not adapt to pastures. Grassland grasses probably do not recover spontaneously in abandoned pastures and in other agricultural lands. Thus, conservation of grassland birds will strongly depend on a urgent programme of identification and protection of large areas of Cerrado dominated by campo limpo and campo sujo. These species would also benefit from the maintenance of a band of grassland along gallery forests.

Abstract:In the Cerrado, veredas are linear physiognomies that occur on hydromorphic soil usually along narrow water courses. They often growth on flat terrain or near headwaters. They are characterised by the abundance of buriti palms (Mauritia flexuosa) that growth over other trees, numerous shrubs and a dense herbaceous stratum. Despite being common landscape elements through the Cerrado's extension, the use of veredas by birds has not been examined in detail. This study aimed to review studies of birds and veredas in the Cerrado. Publications (n = 25) reported the use of veredas by 261 bird species. Only 13 of them had aspects of their biology (reproduction and feeding) studied in detail. Veredas are poorly used by Cerrado's endemic species, but are the major habitat requirement of several species. The richness of bird species found in veredas is increased by their inclusion in the home range of forest, savanna and grassland species. This study also discusses the values of veredas to the regional biodiversity, and the major threats to their conservation inside and outside the system of nature reserves. Suggestions for future research on birds and veredas in Cerrado also are provided. Keywords: grassland, landscape, Mauritia, savanna, wetland.TUBELIS, D.P. Veredas e seu uso por aves no Cerrado, América do Sul: uma revisão. Biota Neotrop. 9(3): http://www.biotaneotropica.org.br/v9n3/pt/abstract?thematic-review+bn02209032009. Resumo:No Cerrado, veredas são fisionomias com formato linear que ocorrem em solos hidromórficos geralmente ao longo de estreitos cursos d'água. Crescem usualmente em relevo plano ou próximo a nascentes. São marcadas pela abundância de buritis (Mauritia flexuosa), que se destacam sobre outras árvores, arbustos, e um denso estrato herbáceo. Apesar de serem comuns elementos de paisagens em toda a extensão do Cerrado, o valor de veredas às aves ainda não foi examinado em detalhe. Este trabalho teve como objetivo revisar os estudos envolvendo aves e veredas no Cerrado. Publicações (n = 25) mencionaram o uso de veredas por 261 espécies de aves no Cerrado. Somente 13 dessas espécies tiveram aspectos de sua biologia (reprodução ou alimentação) estudados em detalhe. Veredas são pouco usadas por espécies endêmicas do Cerrado, mas são o principal requerimento de hábitat de algumas espécies de aves. A riqueza de espécies de aves encontrada em veredas é em grande parte aumentada pela sua inclusão na área de vida de espécies florestais, savânicas e campestres. Este estudo também discute os valores de veredas à biodiversidade do Cerrado, e as principais ameaças à sua conservação dentro e fora do sistema de reservas naturais. Também são fornecidas sugestões para pesquisas futuras envolvendo aves e veredas no Cerrado. Palavras-chave: área úmida, campo, Mauritia, paisagem, savana.

We surveyed birds in patches of native eucalypt forest and in surrounding exotic matrix (Radiata pine forests) in southeastern Australia. Our objectives were: (1) to examine the influence of the width of native forest patches and the age of surrounding pine forests on bird occurrence in patches of native forest; and (2) to verify the relationship between the use of the surrounding pine matrix and bird species response to variation in width of patches of native forests. A total of 32 study sites (boundaries between eucalypt and pine forests) were surveyed. Birds were counted by the area search method within 0.5-ha quadrats. Data were analysed using generalised linear models. Wide patches of eucalypt forest supported higher species richness and greater numbers of birds, such as foliage searchers and nectarivores, than narrow patches. Matrix age also influenced the occurrence of some species in native patches. The abundance of species in wide and narrow patches of native forest was related to their use of the matrix. This was true for native forests surrounded by old but not by young pine forests. We suggest that management in wood production landscapes take into account both characteristics of native patches and the surrounding matrix. Negative impacts of fragmentation in managed landscapes might be reduced by promoting matrix types that are suitable for bird species.

The peninsula effect -a decrease in species richness from the base to the tip of a peninsula -has been tested for a diverse range of taxa at continental and regional scales. We investigated the peninsula effect at a local scale by examining bird species occurrence in riparian strips (peninsulas) of native eucalypt forest within a radiata pine plantation in the Tumut region, south-eastern Australia. Peninsulas were elongated but 'blind' extensions of a core area of native eucalypt forest. Birds were surveyed by the area search method, within 1.0-ha quadrats established along peninsulas (n =14), in October and November 2002. Data were analysed using generalized linear mixed models. A significant decrease in bird species richness from the base towards the tip of the peninsulas was observed. The proportion of large bird species recorded per quadrat showed a significant decrease from the base towards the tip of the peninsulas. This pattern was not observed for small birds. Several species were more abundant at the base of the peninsulas than away from the core area of eucalypt forest. The peninsula effect can occur locally in landscape mosaics. Factors leading to the observed patterns of species occurrence may be distinct from those proposed in investigations of the peninsula effect with a biogeographical (macroscale) context. In our microscale study, foraging incursions of individual birds from the core area of native forest through peninsulas were a major factor giving rise to higher bird species richness in the more basal portions of peninsulas.

We examined the role of mixed-species flocks for forest birds during their breeding and non-breeding seasons in the use of savannas adjacent to forests in central Cerrado, Brazil. Transect surveys (n = 64) were conducted in eight savanna patches. Distances of birds from forests were estimated. Recorded birds were classified as members or not of mixed-species flocks. About half of the bird species recorded in savannas were found in at least one mixed-species flock. As distance from the forest increased, the number of species in mixed-species flocks tended not to vary, while the number of species foraging alone or in mono-specific groups decreased. Thus, for some forest species, participation in mixed-species flocks allowed a greater use of more distant savannas. This tendency of being in mixed-species flocks at greater distances from forests also can be interpreted as a reluctance to forage alone or in mono-specific groups due to higher predation risk in less protective vegetation distant from cover. There was strong seasonal variation in the participation of bird species in mixed-species flocks. There were significantly more species in mixed-species flocks than out of these associations in the non-breeding season, while differences in the breeding season were not significant. These patterns occurred, in part because mixed-species flocks tended to be more frequent, to have more species and to forage at greater distances from forests during the early non-breeding season than in other periods. This study suggests that the formation of mixed-species flocks plays an important role in promoting the use of adjacent savannas by forest birds at forest/savanna boundaries in Cerrado. It also pointed out a novel advantage gained by birds with participation in mixed-species flocks -greater use of adjacent vegetation patches.

This study aimed to identify food items of the Blue-and-yellow Macaw (Ara ararauna) flocks foraging at firebreaks in western Cerrado, Brazil. Also, I discuss ecological aspects of macaw feeding activities at firebreaks. Two 3,500ha portions of Emas National Park were selected for observations. The sites were mosaics of woodland savanna and shrubby grassland, crossed and bordered by firebreaks and adjacent unsealed roads. A total of 76 foraging flocks of macaws were recorded at firebreaks between September 2006 and February 2007. Seven plant species were identified as food items. Seeds of a shrub species (Anacardium humile) were the most often consumed resource. Parts of other plant species were sometimes consumed. Macaws perched in tree canopies to consume their young apical parts, young leaves, flowers and parts of branches. The frequency of consumption of parts of shrubs was significantly higher than that of trees. At Emas National Park, numerous Blue-and-yellow Macaw flocks are attracted to firebreaks mainly by fruiting A. humile patches. Their foraging activities often damage reproductive and young parts of shrubs and trees.Key words: Anacardium humile, bird, diet, fire ecology, savanna ResumoEcologia alimentar de Ara ararauna (Aves, Psittacidae) em aceiros no oeste do Cerrado, Brasil. Este estudo teve como objetivo identificar itens alimentares de bandos de araras-canindé (Ara ararauna) forrageando em aceiros na região oeste do Cerrado, Brasil. Eu discuto aspectos ecológicos de atividades alimentares de araras em aceiros. Duas porções (cerca de 3.500ha cada) do Parque Nacional das Emas foram selecionadas para o estudo. Os locais de estudo eram mosaicos de campo cerrado e campo sujo cruzados e envoltos por aceiros e estradas de terra adjacentes. Um total de 76 bandos foi registrado forrageando em aceiros entre setembro de 2006 e fevereiro de 2007. Sete espécies de plantas foram identificadas como itens alimentares. Sementes de cajuzinhos-do-cerrado (Anacardium humile) foram o recurso mais frequentemente consumido. Partes de outras espécies de plantas foram eventualmente consumidas. Araras pousaram em copas de árvores para consumir suas partes apicais, folhas jovens, flores e parte de galhos. A frequência de consumo de partes de arbustos foi significantemente mais alta do que aquela de árvores. No Parque Nacional das Emas, numerosos bandos de arara-canindé são atraídos a aceiros principalmente por manchas de cajuzinhos em frutificação. Suas atividades alimentares geralmente causam danos a partes reprodutivas e apicais de arbustos e árvores.Unitermos: Anacardium humile, aves, dieta, ecologia do fogo, savana Biotemas, 22 (2): 105-115, junho de 2009