Foraging behaviour of bird pollinators on Embothrium coccineum (Proteaceae) trees in forest fragments and pastures in southern Chile

Abstract We investigated the effects of forest patch size on the behaviour of birds feeding on the flower nectar of the proteaceous tree Embothrium coccineum J. R. et G. Forster, which is typically restricted to forest edges in agricultural landscapes in southern Chile. We quantified reproductive parameters of trees (no. inflorescences per branch, total and open flowers per inflorescence) in forest fragments varying from 1 ha (small), to 20 ha (medium) and to >150 ha (large), and in remnant trees in pastures. Visits to flowers by nectar‐feeding birds were recorded during 30‐min observation periods, spread throughout the day during two flowering seasons, November 1992 and 1993 (n = 242 periods overall). Aggressive encounters among flower visitors were recorded in 1992. We expected less visits to trees in pastures and small forest patches because abundances of Embothrium's main pollinators, the flycatcher Elaenia albiceps and the hummingbird Sephanoides sephaniodes, decreased in smaller patches. We found, however, that pollinator visiting rates were negatively correlated with forest patch area and were highest for pasture trees. This trend was largely due a decline in the number of visits by E. albiceps, the main flower visitor, in larger patches. Hummingbird visits did not change with forest patch size. Lower visitation rates to flowering trees in larger forest fragments seemed to be a consequence of territorial defence by E. albiceps and were unrelated to differences in floral display.     

Effects of selective logging (50 years ago) on habitat use and ranging behaviour of a forest understorey bird (red-tailed bristlebill, Bleda syndactyla) in Uganda

To understand the effects of selective logging on animals we compared habitat use and ranging behaviour of a common understorey passerine bird, the red‐tailed bristlebill (Bleda syndactyla), in logged and unlogged forest in the Budongo Forest Reserve, Uganda. The secondary forest had been selectively logged about 50 years ago, and differed in vegetation structure from the unlogged, primary forest in particular by having a denser understorey. Home range size of radio‐tagged bristlebills was 10–20% larger (depending on data sample used) in unlogged forest compared with logged forest, but the difference was not significant. Movement rates during 1‐h observation periods were highest in unlogged forest. The bristlebill has been characterized as a bird of dense understorey vegetation, and data from unlogged forest in the present study suggested that areas with dense understorey were used more often than expected. In logged forest, no habitat preferences were found, probably because the forest had a dense understorey throughout. Assuming that smaller home ranges and lower movement rates indicate better habitat, there was no evidence that bristlebills were negatively affected by logging. The preference for dense understorey in unlogged forest suggests that the bristlebill may benefit from selective logging because this leads to an increase in dense understorey.     

Dung beetles in pasture landscapes of Central America: proliferation of synanthropogenic species and decline of forest specialists

This study examines the spread of synanthropogenic dung beetles (species favoured by human activities) in pasture landscapes in Central America, and evaluates the role of forest fragments and regenerating patches of native vegetation in maintaining beetle diversity. Pitfall trapping was carried out at nine locations in El Salvador and seven in Atlantic Nicaragua that included both pasture and remnant or regenerating native vegetation. More dung beetle species occurred in forest fragments than in pastures. Community composition differed considerably between forest fragments from El Salvador and Nicaragua with many species restricted to either the Caribbean or Pacific regions. In contrast, dung beetle community composition and structure were largely the same in the pastures of El Salvador and Nicaragua, regardless of region or original habitat-type, and were similar to published results from pastures in Mexico and elsewhere on the Isthmus. Very small patches of native shrubs and tree stands (<2.5 ha) maintained no forest specialists in Nicaragua, whereas, in El Salvador, some forest specialists occurred even in the smallest stands of trees (ca. 0.25 ha). The study indicates that the expansion of cattle pastures has caused a regional decline in dung beetle diversity. Forest fragments and small isolated patches of native trees and shrubs maintain some of the diversity of the original landscape but their conservation value for dung beetles will depend on the biogeographical history of the sites.     

Disturbance, selective logging and bird diversity: a Neotropical forest study

The composition and structure of bird communities, and the damage to forest structure were surveyed in northern French Guiana (northeastern Amazonia) one year and ten years after selective logging and compared with the situation in a similar undisturbed primary forest. A point-count method was used in which 937 0.25ha sample plots were censused for 20 minutes each, and their vegetation structure was measured. On average, 38% of the forest undergrowth was destroyed, then invaded by dense regrowth, and up to 63% of the canopy was substantially opened as a result of selective logging. Hunting pressure also increased due to access roads opened for logging. Among the 256 species recorded, overall bird species richness and abundance were depressed by 27–34% in the logged areas compared to primary forest. The most vulnerable guilds, which decreased by 37–98% in abundance, were mature forest understorey species, especially terrestrial ones and mixed flocks of insectivores. Hummingbirds, small gaps, vine tangles and canopy species did not decrease, nor increase significantly after logging. Only species naturally associated with dense second growth, forest edges and large gaps actually increased. Habitat specialization was the major determinant of vulnerability to logging, and, to a lesser degree, size (large) and diet (insectivorous), but foraging behaviour and rarity had little effect. Bird sensitivity to changes in logged forest structure may involve physiological intolerance, reduced food categories, increased exposure to predators, too dense understorey for their specific foraging behaviour and/or avoidance of gaps. Suggested improvements of current forest management and logging techniques for the maintenance of a higher proportion of the original biodiversity include minimizing logging damages, long rotations (>50 years) between cuts, and keeping unlogged forest patches within logging concessions.     

Influence of within‐patch habitat quality on high‐Andean Polylepis bird abundance

Habitat restoration strategies for fragmented high Andean forest landscapes must consider the influence of within‐patch habitat quality on bird abundance. I examined vegetation and bird abundance at three locations within a highly fragmented Polylepis forest landscape in the Cordillera Vilcanota, southern Peru. Across the landscape, there was significant variation in the vegetation structure of Polylepis forest patches of different size categories, especially in terms of tree girth, tree height, tree density, and canopy vegetation structure. Principal Component Analysis extracted five factors of habitat quality, which together accounted for 74.2% of the variability within 15 habitat variables. Polylepis bird species differed in their responses to habitat quality but, overall, variation in Polylepis bird abundance was not fully captured by the range of habitat quality variables. Tall, dense vegetation cover was clearly important for 11 conservation‐important species, a high density of large trees was important for 10 species and primary forest ground cover was important for eight species. Habitat quality exhibited no significant influence on the abundance of only one species –Asthenes urubambensis. The abundance of seven species was associated with lower elevation forest, but only one species was associated with higher elevation forest. Management of habitat quality in large and medium remnant forest patches throughout the Cordillera Vilcanota, particularly in the 3800–4200 m elevation range, will be a cornerstone in ensuring the persistence of the majority of conservation‐important bird species populations.     

Landscape mosaic of Araucaria forest and forest monocultures influencing understorey spider assemblages in southern Brazil

Abstract This study investigates how abundance, diversity and composition of understorey spiders were influenced by four different forest habitats in a southern Brazilian Araucaria forest. The study area encompasses a landscape mosaic comprised of Araucaria forest, Araucaria plantation, Pinus plantation, and Eucalyptus plantation. Understorey spiders were collected by beating the vegetation inside three patches of each forest habitat. To assess possible predictors of spider assemblage structure, several patch features were analysed: potential prey abundances, estimation of vegetation cover, diversity index of vegetation types, patch ages, patch areas, and geographical distance between patches. To assess the influence of high‐level taxa approaches on spider assemblage patterns, analyses were carried out individually for family, genera and species levels. Additionally, Mantel tests were carried out in underlying similarity matrices between each taxon. Significant differences in spider abundances among forest habitats were found. Pinus plantations showed the highest abundance of spiders and Eucalyptus plantations showed the lowest abundance. Spider abundance was significantly influenced by patch ages, geographical distance and vegetation cover. Expected numbers of families, genera and species did not vary among forest habitats. Spider composition of two Eucalyptus patches differed from the other forest patches, probably due to their low vegetation cover and isolation. Genera composition was the best correlate of species composition, showing that a higher‐level surrogate can be an alternative to the species approach. The understorey spider diversity in this managed area could be maintained when suitable habitat structures are provided, thus ensuring the connectivity between different habitat types. Further studies should focus on individual species responses to the conversion of native forest to monocultures.     

Effects of small-scale habitat disturbance on the ecology of breeding birds in a Vermont (USA) hardwood forest

We studied territory placement and foraging behavior of breeding birds in relation to juxtaposition of forest vegetation and logged patches in southern Vermont, USA Different bird species used disturbed vegetation at differing spatial scales, depending on temtory size Four species Dendroica pensylvamca. Geothlypis trichas, Zonotrichia albicollis, Oporornis Philadelphia showed strong clumping of their small (< 0 5 ha) territories in logged patches and were absent or rare in undisturbed forest Eleven species (e g Seiurus aurocapillus, Vireo ohvaceus) tended to avoid logged areas, especially the centers of cut patches An additional 17 species fell between these two extremes, using a mixture of disturbed and undisturbed forest and showing no tendency to prefer one or the other These 17 species tended to have larger (1 to > 3 ha) territories than disturbance specialists We used ordination and quantitative matrix comparisons to describe and test relationships among 14 of the most common bird species according to their similarities in territory habitat structure, tree species composition, and foraging behavior These analyses did not reveal any strong associations between foraging behavior and use of cut versus uncut forest Habitat use by birds occupying this forest mosaic, with its strong local gradient of vegetation structure, was thus not associated with concurrent variation in foraging behavior The sizes of cut patches of forest (0 7-1 6 ha) in our study area may be close to the minimum required to attract distinct breeding assemblages of non-forest birds to otherwise undisturbed forest ecosystems Bird species that use patches of early-successional vegetation embedded m a forested landscape may adopt a fugitive strategy as they seek nesting habitats in the spring Careful use of forest management techniques may permit both forest-interior and early-successional bird species to coexist m the landscape     

Stop the bullying in the corridors: Can including shrubs make your revegetation more Noisy Miner free?

Summary   Noisy Miners ( Manorina melanocephala ) are aggressive Australian honeyeaters that dominate many areas of remnant vegetation and forest edges from which they competitively exclude small birds. A similar domination can also occur in planted wildlife corridors. The aim of this study was to determine which corridor plantings encouraged the presence of small native birds in regions where Noisy Miners dominate. Six vegetation mixes were investigated in the main study: eucalypts with and without shrubby understorey; acacia with and without shrubby understorey; exotic conifer; and exotic deciduous trees. A supplementary study then examined sites with a mixture of eucalypt and acacia trees with a shrubby understorey. The findings showed that Noisy Miners dominated corridors of eucalypts, virtually excluding small birds, whereas native acacias, exotic conifer and exotic deciduous corridors had small birds and no resident Noisy Miners. The greatest abundance and richness of small birds occurred in plantings combining eucalypts with at least 15% acacias, in this case bipinnate species. Given these results, it is recommended that eucalypt plantings should be supplemented with both acacias (preferably bipinnate) and a shrubby understorey.     

Preservation of biodiversity in small rainforest patches: rapid evaluations using butterfly trapping

Determining the capacity of small forest remnants to support biodiversity is of critical importance, especially in the tropics where high rates of land conversion coincide with extraordinarily high species richness and endemism. Using fruit-baited traps, we conducted rapid evaluations in 1993 and 1994 of the forest butterfly diversity of seven small patches (3–30 ha) and a single remaining large patch (227 ha) of Costa Rican mid-elevation moist forest. Our results suggest that even recently isolated 20–30 ha fragments of primary forest retain surprisingly depauperate butterfly faunas relative to that supported by the 227 ha patch only 0.5–1.0 km away. If forest butterflies are an index of the diversity of small-bodied organisms in general, preservation of the latter may require unexpectedly large patches. In 1994 we also surveyed a 16 ha botanical garden, situated between and contiguous to both the 227 ha patch and an exceptionally species-rich 25 ha patch. In the garden, we discovered adults of many butterfly species associated with forest interior, suggesting that even heavily managed systems of largely exotic plants (such as agricultural systems) could be designed to serve as corridors for butterflies and perhaps some other groups of organisms. We discuss some implications for a planned restoration of biotic connections between lowland and montane forests in southern Costa Rica.     

Eucalypt plantings on farms benefit woodland birds in south‐eastern Australia

Abstract Most of the original forest and woodland cover on the western slopes of New South Wales and the northern plains of Victoria has been cleared for agriculture (wheat, sheep and cattle) and what remains is highly fragmented and modified by a long history of disturbance. Over the past three decades, native eucalypt trees and shrubs have been planted extensively in a part of this region to provide a range of environmental benefits. Our aim was to determine the extent to which these plantings could improve biological diversity in agricultural landscapes in south‐eastern Australia and to identify the variables influencing their effectiveness. We sampled birds at 120 sites encompassing the range of available patch sizes, stand ages, floristic and structural conditions, and habitat attributes for revegetated areas and remnants of native vegetation, and we compared these to nearby paddocks. Eucalypt plantings were found to provide significant improvements in bird population density compared with cleared or sparsely treed paddocks, and mixed eucalypt and shrub plantings had similar bird communities to remnant native forest and woodland in the region. Birds displayed a strong response to patch size, with both larger (≥5–20 ha) eucalypt plantings and larger (≥5–20 ha) remnants having more species and more individuals per unit area than smaller (<5 ha) patches of these vegetation types. Older (10–25 years) plantings had more bird species and individuals than young (<10 years) plantings. The distance from remnant forest and woodland (habitat connectivity) appeared to be an important variable influencing bird species richness in eucalypt plantings. The main differences were due to the greater numbers of species classified as woodland‐dependent in the larger‐sized patches of plantings and remnants. Eucalypt plantings provided useful habitat for at least 10 declining woodland‐dependent species, notably for the Speckled Warbler, Red‐capped Robin and Rufous Whistler. The Brown Treecreeper and Dusky Woodswallow appeared to be the species most limited by the extent of remnant forest and woodland in the region. Plantings of all shapes and sizes, especially those larger than 5 ha, have an important role to play in providing habitat for many bird species. Restoration efforts are more likely to be successful if eucalypt plantings are established near existing remnant vegetation.     

Can vegetation corridors support a small mammal community similar to that found within forest fragments? A case study in southeastern Brazil

Vegetation corridors are generally proposed as a strategy to reduce forest fragment isolation in fragmented landscapes. In southern Minas Gerais, Brazil, vegetation corridors emerged naturally after native trees colonized excavations used as boundaries by farm owners in the eighteenth century. We tested the use of these structures by small mammals and compared diversity among corridors and forest fragments. Community richness and abundance were similar in corridors and forest fragments, and we identified movements of small mammals between corridors and forest fragments. We suggest that governmental policies should encourage farm owners to conserve vegetation corridors, especially in this fragmented landscape.     

Habitat use by Oncifelis guigna and Pseudalopex culpaeus in a fragmented forest landscape in central Chile

Native forests in Chile have been replaced by exotic plantations, generating a mosaic of forest fragments immersed in a matrix of plantations and farms. This landscape change could affect habitat availability for native carnivores such as Oncifelis guigna (Felidae) and Pseudalopex culpaeus (Canidae). We determine the potential impact of native forest fragmentation on these species, assessinghabitat use by these carnivores. The study was carried out in continuous forest (150 ha), native forest fragments (<10 ha) and surrounding pine plantations in central Chile (35°59 S, 72°41 W). We placed scent-stations (SSs) in three types of habitat from January to August 2000, setting a total of 620 SSs to determine habitat selection. We characterized structure and composition of 100 m² of vegetation aroundevery SS, and measured its distance to nearest native forest patch, road and bottom creek. O. guigna preferred habitats with dense bush cover, far from roads and close to large patches of native forest, being almost exclusively restricted to this type of habitat. On the other hand, P. culpaeus preferred openhabitats, close to roads, relying extensively on pine plantations but scarcely using forest and forest fragments. Our results suggest that native forest fragmentation, considering habitat use only, would have a negative effect on O. guigna populations. Thus, forest size reduction and isolation may reduce O.guigna survival in a pine dominated landscape. In contrast, P. culpaeus, a generalist species that would use habitat depending on its abundance, may adapt to changes in this landscape.     

Habitat selection and reproductive success of Ortolan Buntings Emberiza hortulana on farmland in central Sweden – the importance of habitat heterogeneity

Many granivorous birds have shown severe population declines in Europe during recent decades. The aim of the present study was to analyse habitat preferences and reproductive success of one such species, the Ortolan Bunting Emberiza hortulana, in different farmland habitats in south‐central Sweden. Four seemingly different land‐use types were preferred: permanent set‐asides, short rotation coppice, and grazed and unmanaged semi‐natural pastures. Territories and random sites differed considerably in the proportion of these preferred land‐use types; 39% of territories had > 70% preferred habitat (at the 100‐m scale) compared to 5% of random sites. In contrast, 22% of territories and 65% of random sites had no preferred habitats. All the preferred habitats had heterogeneous ground vegetation characterized by patches with bare ground, or at least sparse ground vegetation, intermixed with patches with taller vegetation. Ortolan Buntings also preferred a heterogeneous habitat structure with occurrence of field islets, shrubby edges, barns and electric wires, which could act as song posts or suitable nest‐sites, in 88% of territories. At a larger (1‐km square) scale, territories occupied by pairs aggregated strongly in areas with high proportions of preferred habitats. The number of territories with single males correlated positively with the number of pairs, which suggests that conspecific attraction may influence territory distribution. No measured habitat factors were related to reproductive success. However, due to habitat preferences and the higher proportion of paired males in one habitat type (set‐aside), the production of young (fledglings/ha) is expected to be higher in set‐asides, as well as in short‐rotation coppices and semi‐natural pastures. Thus, these habitats are important for the conservation of the Ortolan Bunting. Large areas with habitat structures such as field islets are especially important because the Ortolan Bunting breeds in aggregations in these areas.     

Eurasian badger habitat selection in Mediterranean environments: Does scale really matter?

It is widely believed that spatial scale affects habitat selection, and should influence management options, especially for species with wide geographic distribution or large territories. Eurasian badger habitat selection has been well studied throughout most of its European distribution range, but never at multiple spatial scales. We used compositional analysis to assess habitat selection of Eurasian badgers in southern Portugal at four spatial scales (1, 4, 25, and 100 km²). We assessed habitat use from setts, latrines and footprints presence, and road kills. Oak woodlands with understorey were selected at all scales, being the most preferred habitat at 3 scales (1, 4, and 100 km²). Pastures were most selected at the scale of the 25 km² cell, but their use was not significantly different from oak woodland with understorey. Shrubs and pastures were also secondly important at the majority of scales. Contrary to findings at northern latitudes, deciduous forests decreased in importance as cell size increased. In the highly humanized and fragmented landscape of southern Portugal, Eurasian badgers are selecting the matrix of oak woodlands interspersed with patches of pastures, shrubs and riparian vegetation. In these oak woodlands, scale does not have a marked effect. Management for badgers should provide, for at least, 30% of oak woodland cover at all scales. Our study illustrates the across-scale importance of maintaining the historically human altered, sustainable and unique landscape and land use system – the montado.     

Structure and diversity of phyllostomid bat assemblages on riparian corridors in a human‐dominated tropical landscape

Tropical forests around the world have been lost, mainly because of agricultural activities. Linear elements like riparian vegetation in fragmented tropical landscapes help maintain the native flora and fauna. Information about the role of riparian corridors as a reservoir of bat species, however, is scanty. We assessed the value of riparian corridors on the conservation of phyllostomid bat assemblage in an agricultural landscape of southern Mexico. For 2 years (2011–2013), mist‐netting at ground level was carried out twice during the dry season (December to May) and twice during the wet season (June to November) in different habitats: (1) riparian corridors in mature forest, (2) riparian corridors in pasture, (3) continuous forest away from riparian vegetation, and (4) open pastures. Each habitat was replicated three times. To determine the influence of vegetation structure on bat assemblages, all trees (≥10 cm dbh) were sampled in all habitats. Overall, 1752 individuals belonging to 28 species of Phyllostomidae were captured with Sternodermatinae being the most rich and abundant subfamily. Riparian corridors in mature forest and pastures had the greatest species richness and shared 65% of all species. Open pastures had the lowest richness and abundance of bats with no Phyllostominae species recorded. Six of the 18 species recorded could be considered as habitat indicators. There was a positive relationship between bat species composition and tree basal area. Our findings suggest that contrary to our expectations, bats with generalist habits and naturally abundant could be useful detector taxa of habitat modification, rather than bats strongly associated with undisturbed forest. Also in human‐dominated landscapes, the maintenance of habitat elements such as large trees in riparian corridors can serve as reservoirs for bat species, especially for those that are strongly associated with undisturbed forest.     

Experimental effects of kelp canopies on subtidal coralline algae

Plants are often grouped as canopy species or understorey species because it is thought that that these sets of taxa interact in predictable ways. Mensurative experiments in southern Australia demonstrated that the percentage cover of encrusting coralline algae was greater, and articulated (branching) coralline algae less, on boulders under a canopy of dense kelp (>7 plants per m²), Ecklonia radiata, than on boulders without kelp. Experimental clearances of kelp and reciprocal transplants of boulders between patches of E. radiata and patches without kelp showed that canopies maintained and facilitated the growth of encrusting coralline algae and reduced the cover of articulated coralline algae. Potential artefacts associated with clearing kelp and transplanting boulders were not detected when tested with a series of translocation controls. These results reject the model that the co‐occurrence of E. radiata and encrusting corallines is just an assemblage of plants caused by spatial and temporal coincidence. Instead, they support the model that kelp facilitates the growth and survival of understorey algae.     

Woody plant communities of isolated Afromontane cloud forests in Taita Hills,Kenya

In the Taita Hills in southern Kenya, remnants of the original Afromontane forest vegetation are restricted to isolated mountain peaks. To assess the level of degradation and the need for forest restoration, we examined how forest plant communities and their indicator species vary between and within remnant patches of cloud forest. We used ordinal abundance data to compare plant communities in eight forest fragments. We also analyzed data on the diversity and abundance of trees in 57 0.1 ha plots to compare tree communities within and between the largest two of these fragments, Ngangao (120 ha) and Mbololo (220 ha). The extant vegetation of the Taita Hills at landscape scale consists of secondary moist montane to intermediate montane forest. There was a high species dissimilarity between fragments (69%). Variation in species composition coincided with an abiotic gradient related to elevation. At plot level, secondary successional species and species of forest edges were most abundant and most frequent. Inferred clusters of plots almost entirely coincided with the two forest fragments. Indicator species associated with forest margins and gaps were more frequent in the smaller of the two forest fragments, while indicators for the larger fragment were more typical for less disturbed moist forest. Abiotic site variability but also different levels of disturbance determine site-specific variants of the montane forest. Conservation efforts should not only focus on maintaining forest quantity (size), but also on forest quality (species composition). Late-successional rainforest species are underrepresented in the woody plant communities of the Taita Hills and assisting restoration of viable populations of cloud forest climax tree species is urgently needed.     

Effects of habitat transitions on rainforest bird communities across an anthropogenic landscape mosaic

We compared bird community responses to the habitat transitions of rainforest‐to‐pasture conversion, consequent habitat fragmentation, and post‐agricultural regeneration, across a landscape mosaic of about 600 km² in the eastern Australian subtropics. Birds were surveyed in seven habitats: continuous mature rainforest; two size classes of mature rainforest fragment (4–21 ha and 1–3 ha); regrowth forest patches dominated by a non‐native tree (2–20 ha, 30–50 years old); two types of isolated mature trees in pasture; and treeless pasture, with six sites per habitat. We compared the avifauna among habitats and among sites, at the levels of species, functional guilds, and community‐wide. Community‐wide species richness and abundance of birds in pasture sites were about one‐fifth and one‐third, respectively, of their values in mature rainforest (irrespective of patch size). Many measured attributes changed progressively across a gradient of increased habitat simplification. Rainforest specialists became less common and less diverse with decreased habitat patch size and vegetation maturity. However, even rainforest fragments of 1–3 ha supported about half of these species. Forest generalist species were largely insensitive to patch size and successional stage. Few species reached their greatest abundance in either small rainforest fragments or regrowth. All pastures were dominated by bird species whose typical native habitats were grassland, wetland, and open eucalypt forest, while pasture trees modestly enhanced local bird communities. Overall, even small scattered patches of mature and regrowth forest contributed substantial bird diversity to local landscapes. Therefore, maximizing the aggregate rainforest area is a useful regional conservation strategy.     

Protected cerrado fragments grow up and lose even metapopulational birds in central S?o Paulo, Brazil.

Moderately dense woodland (cerrad?o) grew in two isolated patches of bushy savanna (cerrado) in central S?o Paulo over 23 years of bird censuses. Various uncommon birds were lost and some forest species were permanently gained. Fall and winter fruits attract long and short-distance migrants. Woodpeckers and some birds that nest in their holes seem to disappear during tree growth. Some birds in weedy areas nearby disappeared when the pastures replaced these areas, however sugar cane reduced the numbers of birds even more up to the point when some areas became pastures once more. Even travel-prone species disappear with vegetation growth in cerrado protected fragments, and therefore "metapopulations" may not survive over time, only in space.     

Nest-predation at the edge: an experimental study contrasting two types of edges in the dry Chaco, Paraguay

Forest fragmentation leads to the creation of isolated forest patches with subsequent impact on forest-interior flora and fauna. Forested corridors have been suggested to alleviate some of the impact by increasing the connectivity between remnant forest patches. However, both fragmentation and corridors increase the ratio of edge to core habitat. We studied nest predation of artificial nests at edges between I) contiguous forests and pastures and 2) forested corridors and pastures, in a forest-dominated landscape in the dry Chaco, Paraguay, The aim was lo determine if nest predation was higher near habitat edges compared to within forests and pastures, with special emphasis on edges at forested corridors. We found that predation rates were similar at edges and in interior habitats. Nest predation was higher for both ground and shrub nests in forested areas than in pastures, Predation rates were also higher for both ground and shrub nests at edges along forested corridors compared to edges neighbouring contiguous forests. Forested corridors connecting contiguous forests may thus act as an ecological sink for some species breeding here. Analysis of predator categories revealed that ground nests in pastures were relatively more depredated by mammals and less by birds, compared to both shrub nests in pastures and ground nests in forests.