scholarly journals A comparison of bird communities in natural and revegetated grasslands in south Brazil

2019 ◽  
Vol 27 (3) ◽  
pp. 199-206
Author(s):  
Rafael Gustavo Becker ◽  
Gabriela Paise ◽  
Marco Aurélio Pizo

AbstractNatural grasslands are declining due to loss, fragmentation and degradation, resulting in the decline of grassland-associated bird species. The Pampas Biome in south Brazil is not exception to this worldwide trend, facing the expansion of croplands and afforestation with exotic tree plantations for cellulose production. To cope with the continuous degradation and loss of grasslands, restoration is an important conservation strategy, but basic information regarding the response of the fauna to restoration practices in southeastern South America grasslands is lacking. Here we compared the structure of bird communities in natural grasslands and revegetated grasslands after mining by planting native and exotic grasses. We sampled birds using 5-min point counts with unlimited radius in three replicates of each habitat (natural and revegetated grasslands; average size 22.2 ± 2.3 ha). We also compared the vegetation density between the two habitat types. The structure of bird communities at natural and revegetated grasslands differed, with natural grasslands presenting higher species richness (42 vs. 35 species) and abundance (1459 vs. 839 records) than revegetated areas, and also a distinct species composition. Ten of the 11 grassland species that were associated to one of the two habitat types occurred more frequently in natural grasslands, which had higher vegetation density than revegetated areas. Even a decade after the beginning of the restoration process, revegetated areas did not resemble natural grasslands in bird species richness, abundance, and composition. These results differed from another study conducted in the Brazilian Pampas in which native plant species were used to actively restore a grassland. Therefore, until we have additional studies addressing the use of exotic grasses for the recovery of bird communities in South America grasslands, we encourage greater representation of native plant species in restoration projects.

2019 ◽  
Author(s):  
Federico Morelli ◽  
Yanina

ContextThe negative association between elevation and species richness is a well-recognized pattern in macro-ecology. ObjectivesThe aim of this study was to investigate changes in functional evenness of breeding bird communities along an elevation gradient in Europe. MethodsUsing the bird data from the EBCC Atlas of European Breeding Birds we estimated an index of functional evenness which can be assumed as a measure of the potential resilience of communities.ResultsOur findings confirm the existence of a negative association between elevation and bird species richness in all European eco regions. However, we also explored a novel aspect of this relationship, important for conservation: Our findings provide evidence at large spatial scale of a negative association between the functional evenness (potential community resilience) and elevation, independent of the eco region. We also found that the Natura2000 protected areas covers the territory most in need of protection, those characterized by bird communities with low potential resilience, in hilly and mountainous areas.ConclusionsThese results draw attention to European areas occupied by bird communities characterized by a potential lower capacity to respond to strong ecological changes, and, therefore, potentially more exposed to risks for conservation.


2008 ◽  
Vol 54 (No. 4) ◽  
pp. 189-193
Author(s):  
M. Żmihorski

Clearcuts are one of the results of forest management. The aim of this study was to assess the effect of clearcuts on bird communities in a managed forest in Western Poland. I applied the method of point transect counts. 20 points were located near clearcuts (less than 100 m from the nearest clearcut) and 25 points in the forest interior. In total, 36 bird species were recorded. On average, I found 9.20 bird species at points located near clearcuts and 6.72 species at points situated in the forest interior, and the difference was significant. The cumulative number of bird species for a given number of sampling points in the vicinity of clearcuts was higher than in the forest interior. The obtained results indicate that in managed, even-aged forests the generation of clearcuts can lead to an increase in local bird species richness.


2013 ◽  
Vol 103 (2) ◽  
pp. 85-96 ◽  
Author(s):  
Lahert W. Lobo-Araújo ◽  
Mário T. F. Toledo ◽  
Márcio A. Efe ◽  
Ana C. M. Malhado ◽  
Marcos V. C. Vital ◽  
...  

The Pernambuco Center of Endemism (PCE) in northeastern Brazil is highly fragmented and degraded. Despite its potential conservation importance the bird fauna in this area is still relatively unknown and there are many remnant fragments that have not been systematically surveyed. Here, we report the results of bird surveys in five forest fragments (one pioneer, two ombrophilous and two seasonal). In total, 162 taxa were recorded, 12 of which are endemic to the PCE. The frequency of endangered species was lower than what has been reported in studies from the same area and most of the taxa considered to be at risk of extinction were sub-species of uncertain taxonomic validity. The comparatively low number of endemic/threatened species may be due to the small size of the fragments in the present study - a consequence of the high levels of habitat loss in this region. Analysis of species richness patterns indicates that ombrophilous forest fragments are acting as refuges for those bird species that are most sensitive to environmental degradation.


The Condor ◽  
2021 ◽  
Author(s):  
Douglas W Tallamy ◽  
W Gregory Shriver

Abstract A flurry of recently published studies indicates that both insects and birds have experienced wide-scale population declines in the last several decades. Curiously, whether insect and bird declines are causally linked has received little empirical attention. Here, we hypothesize that insect declines are an important factor contributing to the decline of insectivorous birds. We further suggest that insect populations essential to insectivorous birds decline whenever non-native lumber, ornamental, or invasive plant species replace native plant communities. We support our hypothesis by reviewing studies that show (1) due to host plant specialization, insect herbivores typically do poorly on non-native plants; (2) birds are often food limited; (3) populations of insectivorous bird species fluctuate with the supply of essential insect prey; (4) not all arthropod prey support bird reproduction equally well; and (5) terrestrial birds for which insects are an essential source of food have declined by 2.9 billion individuals over the last 50 years, while terrestrial birds that do not depend on insects during their life history have gained by 26.2 million individuals, a 111-fold difference. Understanding the consequences of insect declines, particularly as they affect charismatic animals like birds, may motivate land managers, homeowners, and restoration ecologists to take actions that reverse these declines by favoring the native plant species that support insect herbivores most productively.


Author(s):  
Estella B. Leopold

As each of us siblings—Starker, Luna, Carl, Nina, and i— matured and entered our professional lives in different parts of the country, we carried with us a hankering to have a place in the country, a Shack of our own. It is not merely real estate, of course. Instead, it is a camping place for feeling close to the land, a place to work with the land and to observe the ecosystem and its fauna. To “own,” or as the first peoples saw it, to “belong” on a piece of land is exciting and special—a chance to become acquainted with a few favorite species, then to watch them grow. But of course it is way more than that. As Dad said, he chose his land for its backwardness, but it flourished in splendid isolation under our care. Shack land, as we conceived of it, had the potential of being inhabited by a vast number of native bird species, plus a diverse fauna of mammals, which got richer with time. We were excited that the Shack landscape itself had such physical variety; it had hills and dales, a grand river, a series of tributaries animated by spring and fall floods, a standing bottomland forest coursed by those floods and occupied by lively muskrats, with ducks flying in and out of the sloughs, as well as kingfishers and jays. Even though it was “degraded” agricultural land, Dad and Mother saw it as a land of opportunities for the family. While it had a “reduced level of complexity,” the soil was still there, and we could help improve it, which actually means that the right plants could make it better. Prairie is the perfect model for this kind of restoration and recovery. Dad described the upward flow of energy from soils through the plant community as a kind of circuit. After major disruption and loss of native species, the energy circuit is slowed and altered. He asked, “Can the land adjust itself to the new order?” He was sure it could if we reintroduced the native plant species on that cornfield, on that terrace, on that hill, in order for a genuine prairie, with its very efficient energy-flow, to become reestablished.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Alfan A. Rija ◽  
Abubakari S. Mgelwa ◽  
Robert B. Modest ◽  
Shombe N. Hassan

Our current understanding of the vertebrate communities of a newly gazetted Tanzanian coastal national park is limited and strongly taxonomically biased towards large mammals. We conducted bird assessments in three sites in Saadani National Park using species lists to analyze some parameters to inform biodiversity conservation in the area. We recorded 3112 individuals in 268 species falling in 66 families, including 2 endangered, 2 vulnerable, and 6 near threatened species. Both species richness and species diversity varied between sites. Species relative abundances were not different between the sites although some functional groups, especially granivores, were more abundant than others. Bird assemblages included 21 forest specialists (FF-species), 35 forest generalists (F-species), and 68 forest visitors (f-species) overlapping among bushland, wooded grassland, grassland, and thickets suggesting presence of important microhabitats for the forest-associated species in this ecosystem. Bird species richness in a feeding guild also showed marked overlap between habitats suggesting availability of rich food resources for the birds. This paper highlights the importance of maintaining a structurally heterogeneous landscape to sustain diverse bird communities in the area.


2015 ◽  
Vol 40 (1) ◽  
pp. 112-134 ◽  
Author(s):  
Sébastien Larrue ◽  
Jean-François Butaud ◽  
Pascal Dumas ◽  
Stéphane Ballet

Which abiotic factors influence the number of native plant species on remote atolls is an important question to understand better the spatial pattern of the species observed on these low and vulnerable coral islands. However, this issue is still very poorly documented, often due to human degradation, partial botanical surveys or the difficult geographic access of remote atolls for researchers. The remote atolls of Eastern Polynesia, which are among the most isolated in the world, are of great interest for studies of native species’ distribution due to their isolation, low human density and urbanisation. In this study, we selected 49 remote atolls of Eastern Polynesia with complete botanical surveys to test the relative influence of eight abiotic factors on native plant species richness (i.e. indigenous and endemic species). Abiotic factors used as potential predictors included atoll area (km2), shoreline length (km), atoll elevation (m) and index of isolation (UNEP), but also the coastal index of the atoll ( Ic), the distance to the nearest similar atoll (km), the distance to the nearest large volcanic island ≥ 1000 km2 (here, Tahiti as a potential stepping-stone island) and the distance to the nearest raised atoll ≥ 15 m a.s.l. (here, Makatea or Henderson as a potential refugium during sea-level highstands). Spearman’s rank correlation, linear regression analysis and frequency diagrams were used to assess the relative influence of these factors on native species richness. No relationship was found between the species richness and the index of isolation or the distance to the nearest similar atoll. Atoll area and distance to the nearest raised atoll of Makatea explained 47.1% and 40%, respectively, of the native species richness variation observed on the remote atolls. The distance to the volcanic island of Tahiti and the coastal index explained 36.9% and 27.3% of the variation, while elevation and shoreline length explained 23.3% and 18.4% of the variation, respectively. Native species richness on the atolls surveyed increased with the increasing atoll area, elevation and shoreline length, but decreased with the increasing distance to the nearest raised atoll of Makatea and the large volcanic island of Tahiti. This supports the view that the spatial pattern of native species richness observed on the remote atolls was strongly influenced by (i) atoll area but also by (ii) the distance to the raised atoll of Makatea, and (iii) the distance to the volcanic island of Tahiti. This finding suggests that the raised atoll may be viewed as a refugium during sea-level highstands while the large volcanic island played the role of stepping-stone island, both islands influencing the dispersal of native species on remote atolls and attenuating the isolation effect in the study area.


2017 ◽  
Vol 44 (3) ◽  
pp. 259 ◽  
Author(s):  
Mellesa Schroder ◽  
Chloe F. Sato

Context Infrastructure development in ski-resort areas has led to the modification of slopes and, often, the replacement of native plant species with exotic grasses. Modified ski slopes are effectively linear areas of disturbance that separate natural habitat and provide barriers to the movement of native animal species. To overcome these barriers, boulder-filled and culvert-style wildlife crossings have been constructed across disturbed ski slopes and under roadways to facilitate the movement of small native mammal species among areas of remnant habitat, but generally they differ in size and locality. The use of boulder-filled and under-road culvert crossings of different length has not been evaluated. Aims We determine whether fauna utilise wildlife crossings in ski resorts and whether variations in crossing length influence the species using the crossings. Methods We monitored boulder-filled crossings of two size classes (long or short) biannually from March 2009 to April 2013, using hair tubes. We monitored an additional two under-road culvert crossings with remote infrared cameras. Key results The results indicated that all crossings, regardless of size, are utilised by small mammals. However, we detected threatened species, such as Mastacomys fuscus (broad-toothed rat), more frequently in crossings of greater length. Conclusions To maintain linkages for small-mammal populations within ski resorts, we recommend the continued use of boulder-filled crossings on ski slopes. These crossings may be particularly important in facilitating the movement of small mammals across wide areas of ski-slope disturbance. Implications The context and maintenance of crossings is likely to be important for their long-term use by small mammals, as are complementary strategies to restore structural habitat connectivity on ski slopes, such as strategically implemented native vegetation plantings.


2006 ◽  
Vol 28 (1) ◽  
pp. 27 ◽  
Author(s):  
A. C. Grice

Most parts of the Australian rangelands are at risk of invasion by one or more species of non-native plants. The severity of current problems varies greatly across the rangelands with more non-native plant species in more intensively settled regions, in climatic zones that have higher and more reliable rainfall, and in wetter and more fertile parts of rangeland landscapes. Although there is quantitative evidence of impacts on either particular taxonomic groups or specific ecological processes in Australian rangelands, a comprehensive picture of responses of rangeland ecosystems to plant invasions is not available. Research has been focused on invasive species that are perceived to have important effects. This is likely to down play the significance of species that have visually less dramatic influences and ignore the possibility that some species could invade and yet have negligible consequences. It is conceivable that most of the overall impact will come from a relatively small proportion of invasive species. Impacts have most commonly been assessed in terms of plant species richness or the abundance of certain groups of vertebrates to the almost complete exclusion of other faunal groups. All scientific studies of the impacts of invasive species in Australian rangelands have focused on the effects of individual invasive species although in many situations native communities are under threat from a complex of interacting weed species. Invasion by non-native species is generally associated with declines in native plant species richness, but faunal responses are more complex and individual invasions may be associated with increase, decrease and no-change scenarios for different faunal groups. Some invasive species may remain minor components of the vegetation that they invade while others completely dominate one stratum or the vegetation overall.


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