Deforestation and habitat loss resulting from land use changes are some of the utmost anthropogenic impacts that threaten tropical birds in human-modified landscapes (HMLs). The degree of these ...impacts on birds’ diet, habitat use, and ecological niche can be measured by isotopic analysis. We investigated whether the isotopic niche width, food resources, and habitat use of bird trophic guilds differed between HMLs and natural landscapes (NLs) using stable carbon (
δ
13
C) and nitrogen isotopes (
δ
15
N). We analyzed feathers of 851 bird individuals from 28 landscapes in the Brazilian Atlantic Forest. We classified landscapes into two groups according to the percentage of forest cover (HMLs ≤ 30%; NLs ≥ 47%), and compared the isotopic niche width and mean values of
δ
13
C and
δ
15
N for each guild between landscape types. The niches of frugivores, insectivores, nectarivores, and omnivores were narrower in HMLs, whereas granivores showed the opposite pattern. In HMLs, nectarivores showed a reduction of 44% in niche width, while granivores presented an expansion of 26%. Individuals in HMLs consumed more resources from agricultural areas (C
4
plants), but almost all guilds showed a preference for forest resources (C
3
plants) in both landscape types, except granivores. Degraded and fragmented landscapes typically present a lower availability of habitat and food resources for many species, which was reflected by the reduction in niche width of birds in HMLs. Therefore, to protect the diversity of guilds in HMLs, landscape management strategies that offer birds more diverse habitats must be implemented in tropical regions.
The intensification of land‐use changes in tropical forests during the 20th century, mainly caused by deforestation for agricultural uses, had an overwhelming influence on bird assemblages. However, ...how these historical anthropogenic changes have impacted the habitat use and diet of tropical birds is poorly known. Stable isotope analysis (δ13C and δ15N) can be useful in this regard since it provides information not only on the habitat and food resource use but also insights on the dietary niche of species. Here, we aimed to evaluate whether centenary anthropogenic impacts, mainly caused by changes in landscape composition, have affected the resource and habitat use and isotopic niche width of Neotropical birds in a region that comprises two biodiversity hotspots – the Atlantic Forest and Cerrado in southeastern Brazil. We found that the niche width of all bird guilds (frugivore, granivore, insectivore, nectarivore and omnivore) was largely reduced (28–70%) from the 20th century until recently. This niche width reduction was likely associated with historical anthropogenic impacts (e.g. fragmentation, forest loss and change in agricultural practices), which are responsible for the decrease in the availability of habitat and food resources. Moreover, the mean values of δ15N decreased over the years in all bird guilds, which might be attributed to the expansion of agricultural areas and the increase in the use of synthetic nitrogen‐based fertilizers. All the analyzed species, even though some of them are diet and habitat generalists, were strongly influenced by centenary anthropogenic actions. Our results show the consequences of human‐induced changes in land use on the diet and habitat use of tropical birds that persist in fragmented landscapes, which might compromise their long‐term survival and provide useful information to the conservation strategies of bird assemblages in modern landscapes.
Assessment of the suitability of anthropogenic landscapes for wildlife species is crucial for setting priorities for biodiversity conservation. This study aimed to analyse the environmental ...suitability of a highly fragmented region of the Brazilian Atlantic Forest, one of the world's 25 recognized biodiversity hotspots, for forest bird species. Eight forest bird species were selected for the analyses, based on point counts (n = 122) conducted in April–September 2006 and January–March 2009. Six additional variables (landscape diversity, distance from forest and streams, aspect, elevation and slope) were modelled in Maxent for (1) actual and (2) simulated land cover, based on the forest expansion required by existing Brazilian forest legislation. Models were evaluated by bootstrap or jackknife methods and their performance was assessed by AUC, omission error, binomial probability or p value. All predictive models were statistically significant, with high AUC values and low omission errors. A small proportion of the actual landscape (24.41 ± 6.31%) was suitable for forest bird species. The simulated landscapes lead to an increase of c.30% in total suitable areas. In average, models predicted a small increase (23.69 ± 6.95%) in the area of suitable native forest for bird species. Being close to forest increased the environmental suitability of landscapes for all bird species; landscape diversity was also a significant factor for some species. In conclusion, this study demonstrates that species distribution modelling (SDM) successfully predicted bird distribution across a heterogeneous landscape at fine spatial resolution, as all models were biologically relevant and statistically significant. The use of landscape variables as predictors contributed significantly to the results, particularly for species distributions over small extents and at fine scales. This is the first study to evaluate the environmental suitability of the remaining Brazilian Atlantic Forest for bird species in an agricultural landscape, and provides important additional data for regional environmental planning.
Promoting the diversity of biological communities in areas of agricultural production is a very current debate since protected areas may not be sufficient to ensure biodiversity conservation. Among ...the biological communities affected by the production areas are birds, which show rapid responses to changes in the landscape. Here we seek to understand how landscape planning, concerning its composition and configuration, in areas with a matrix of planted
Eucalyptus
spp. forests influences the functional diversity of bird assemblages in the Atlantic Forest. Our results show that the spatial distribution design of planted forests in terms of age, land cover and clone types have effects on bird diversity with regard to functional divergence, functional evenness and species richness. These results reinforce the importance of good management for the maintenance of bird diversity. We found that bird functional diversity in planted forest matrices increased with the proximity index, proportion of native vegetation and age importance value, and is negatively influenced by edge density and proportion of forest plantation. For bird conservation, it is thus better to associate
Eucalyptus
spp. with other cover types in the landscape. These results corroborate that, to increase bird functional diversity, it is possible to associate conservation and production in the same landscape. Mosaic landscapes have great potential to contribute to the conservation of bird biodiversity outside protected areas. However, decisions regarding the management of planted forests and planning of improved areas intended for conservation seem to be decisive to ensure the maintenance of bird biodiversity.
This article details a correction to the article: Alexandrino, E.R., Navarro, A.B., Paulete, V.F., Camolesi, M., Lima, V.G.R., Green, A., de Conto, T., Ferraz, M.P.M. de B., Şekercioğlu, Ç.H. and do ...Couto, H.T.Z., 2019. Challenges in Engaging Birdwatchers in Bird Monitoring in a Forest Patch: Lessons for Future Citizen Science Projects in Agricultural Landscapes. 'Citizen Science: Theory and Practice', 4(1), p.4. DOI: http://doi.org/10.5334/cstp.198
Birdwatchers hold substantial potential as data collectors for research, and in Brazil, the birdwatching community has been growing since the early 2000s. Currently the effects of birds on forest ...patch restoration in agricultural landscapes is a major focus of avian conservation ecology, but these patches are not frequently visited by birdwatchers in Brazil, hindering the collection of useful bird data. We thus developed a project, 'Did I see a banded bird!?', which was designed to attract birdwatching volunteers to monitor birds within a forest patch. We explored three motivating factors to attract birdwatchers: (1) we offered an unprecedented opportunity for birdwatchers to record individual birds with colored bands, a challenging activity appealing to birdwatchers’ competitive nature; (2) our study area offered a new location with free, easy access and no logistical impediments; and (3) we continuously provided information on the benefits of birdwatching records for science and society to encourage participation. The project was widely announced and we had 302 applicants. However, the barriers faced throughout the project’s execution, including limited researcher-volunteer interaction, low security in the patch, and the presence of few species for birdwatchers to see, reduced the motivation and participation of most applicants. Consequently, from a list of 155 highly qualified applicants who lived near the patch and were skilled in forest birding, only 10 visited the patch. Our findings provide important guidelines for researchers planning similar citizen science projects in agricultural landscapes, mainly in countries where citizen science is still not common.
Neocrex erythrops (Sclater, 1867), Paint-billed Crake, is a difficult bird to find and has few, scattered records spread over Brazil. The state of Espírito Santo has only one documented record ...of this species, which is based on a specimen collected in 1940. After 76 years since this first and only record, we present new records of N. erythrops from Espírito Santo. The new data increase the knowledge of this species in the state.
•Bird sensitivity to disturbance (Parker III et al., 1996) was tested as ecological indicator.•Parker's classification failed to predict environmental conditions in patches in HML.•Only high ...sensitivity species locally functioned well as an ecological indicator.•Although flawed, Parker's classification was very used in environmental assessments.•This is the first argument of how Parker's classification is wrongly used as ecological indicator.
An Environmental Assessment (EA) is one of the steps within the Environmental Impact Assessment process. Birds are often used in EA to help decision makers evaluate potential human impacts from proposed development activities. A “sensitivity to human disturbance” index, created by Parker III et al. (1996) for all Neotropical species, is commonly considered an ecological indicator. However, this parameter was created subjectively and, for most species, there have been no rigorous field test to validate its effectiveness as such. Therefore, in this study, we aim to: (1) evaluate if, at the local scale, birds from forest patches in a human-modified landscape (HML) may differ in sensitivity from Parker's sensitivity classification; (2) evaluate the effectiveness of the species richness value at each sensitivity level as an ecological indicator; (3) gather information on how often and in which manner Parker's classification has been used in EA. To do so, bird sampling was performed in eight forest patches in a HML over one year. Then, we created a local sensitivity to disturbance using information about threat, endemism, spatial distribution and relative abundance of all species in the study area. We found that 37% of the forest birds showed different local sensitivity levels when compared with Parker's classification. Our results show that only the richness of high-sensitivity species from our local classification fitted the ecological indicator assumptions helping the environmental conditions evaluation of the studied patches. We conclude that species richness of each Parker's bird sensitivity levels do not necessarily perform as an ecological indicator at the local scale, and particularly in HML. Nevertheless, Parker's Neotropical bird sensitivity classification was used in 50% of EA we reviewed. In these, 76% assumed that it was an accurate ecological indicator of the local forest conditions for birds. The lack of clear criteria used in Parker's classification allows diverse interpretations by ornithologists, and there is no agreement about the ecological meaning of each sensitivity level and what environmental conditions each level may indicate of. Therefore, the use of Parker's classification in EA may jeopardize accurate interpretations of proposed anthropogenic impacts. Furthermore, because a bird species’ sensitivity often varies between locations, we argue that Parker's generalized classification of bird sensitivity should not be used as an indicator of forest environmental conditions in EA throughout HMLs in Neotropics. Rather, local bird ecological indices should be explored, otherwise, erroneous predictions of the anthropogenic impacts will continue to be common.
•Used bird-based Index of Biotic Integrity (B-IBI) to assess small forest patches.•B-IBI has identified seven avian ecological traits useful in assessment.•B-IBI identified patch integrity while ...species richness and Shannon diversity did not.•Conceptual imparity between test methods accounts for assessments differences.•B-IBI is a promising method for tropical forest patch assessment in HMLs.
Wooded biomes converted to human-modified landscapes (HML) are common throughout the tropics, yielding small and isolated forest patches surrounded by an agricultural matrix. Diverse anthropogenic interventions in HMLs influence patches in complex ways, altering natural dynamics. Assessing current condition or ecological integrity in these patches is a challenging task for ecologists. Taking the Brazilian Atlantic Forest as a case study, we used the conceptual framework of the Index of Biotic Integrity (IBI), a multimetric approach, to assess the ecological integrity of eight small forest patches in a highly disturbed HML with different configurations and histories. The IBI was developed using bird assemblages found in these patches, and its performance was compared with analytical approaches commonly used in environmental assessment, such as general richness and Shannon’s diversity index. As a first step, the IBI procedure identifies an existing gradient of human disturbance in the study region and checks which biotic characteristics (candidate metrics) vary systematically across the gradient. A metric is considered valid when its’ relationship with the gradient provides an ecological interpretation of the environment. Then, the final IBI is elaborated using each valid metric, obtaining a score for each site. Over one year of sampling, 168 bird species were observed, providing 74 different bird candidate metrics to be tested against the disturbance gradient. Seven of them were considered valid:richness of threatened species; richness of species that use both “forest and non-forest” habitats; abundance of endemics, abundance of small understory-midstory insectivores, abundance of exclusively forest species; abundance of non-forest species, and abundance of species that forage exclusively in the midstory stratum. Each metric provided complementary information about the patch’s ecological integrity. The resulting IBI showed a significant linear relationship with the gradient of human disturbance, while total species richness and Shannońs diversity index did not. Application of numerical approaches, such as total species richness and Shannon’s diversity, did not distinguish ecological traits among species. The IBI proved better for assessing and interpreting ecological and environmental condition of small patches in highly disturbed HML. The IBI framework, its multimetric character, and the ease with which it can be adapted to diverse situations, make it an effective approach for assessing environmental conditions in the Atlantic Forest region, and also for many other small forest patches in the tropics.
Neocrex erythrops
(Sclater, 1867), Paint-billed Crake, is a difficult bird to find and has few, scattered records spread over Brazil. The state of Espírito Santo has only one documented record of ...this species, which is based on a specimen collected in 1940. After 76 years since this first and only record, we present new records of
N. erythrops
from Espírito Santo. The new data increase the knowledge of this species in the state.
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