scholarly journals Effects of a recalcitrant understory fern layer in an enclosed tropical restoration experiment

NeoBiota ◽  
2020 ◽  
Vol 59 ◽  
pp. 99-118
Author(s):  
Luis C. Beltrán ◽  
Karla María Aguilar-Dorantes ◽  
Henry F. Howe
Keyword(s):  
Species Richness ◽  
Canopy Cover ◽  
Mortality Rates ◽  
Invasion Success ◽  
Forest Fragments ◽  
Mixed Species ◽  
Dispersal Mode ◽  
Seed Addition ◽  
Tree Canopies ◽  
Forest Strata

Establishing mixed-species tree plantings and fencing them to protect seedlings from herbivory is a valuable strategy for reconnecting forest fragments separated by agropastoral lands. However, fencing may provide exotic plants with the escape from herbivory required to invade the understory of planted communities. Here we take advantage of such a situation to ask how the identity of planted species and the resulting canopy cover influenced invasion success by the Asian swordtail fern (Nephrolepis brownii Desv. Nephrolepidaceae) in a 13-year-old tropical restoration experiment. Through a seed addition experiment, we also evaluated the effects the ferns had on recruiting seedlings. We found that the invasion was most acute in the unplanted control plots where canopy cover was consistently scarce. Frond density correlated negatively with canopy cover, though most of the variance in the model is explained by the design of our experiment (r2m = .161, r2c = .460). Between planting treatments that differed in the dispersal mode of the planted trees, the wind-dispersed treatment had higher fern density and longer fronds than the animal-dispersed treatment. The animal-dispersed treatment had the highest recruiting species richness, which was negatively correlated with fern density (r2 = .748). The seed addition experiment confirmed that mortality rates increased where frond density was higher (F1,41 = 7.159, p = .011) and germination rates were lowered for the smaller-seeded species (F1,42 = 13.2, p = .002). To prevent recalcitrant understory layers from establishing in plantings in the future, we recommend: (1) establishing larger plantings or expanding existing ones to minimize edge effects (particularly light filtration), (2) supplementing young plantings with additional seedlings to prevent canopy gaps from forming, and (3) planting an assemblage of species that cover the full forest strata and have consistently full tree-canopies.

scholarly journals Effects of Forest Fragment Size and Successional Stage on Mixed-Species Bird Flocks in Southeastern Brazil

The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 585-594 ◽  
Author(s):  
Marcos Maldonado-Coelho ◽  
Miguel  Marini
Keyword(s):  
Species Richness ◽  
Size Structure ◽  
Fragment Size ◽  
Southeastern Brazil ◽  
Size Analysis ◽  
Forest Fragments ◽  
Forest Fragment ◽  
Mixed Species ◽  
Successional Stage ◽  
Mixed Species Flocks

Abstract We analyzed patterns of species richness, size, structure, and composition of mixed-species flocks in relation to forest fragment size and forest successional stage during dry and rainy seasons, at the state of Minas Gerais, southeastern Brazil. Three forest fragments (1.7, 50, and 200 ha) were used for fragment size analysis, and two fragments (200 and 300 ha) were used for successional stage analysis. Fragment size and season affected flock richness, size, stability, and composition. In the 1.7-ha fragment, flock species richness, size, and stability were significantly different only during the rainy season. Fragment successional stage also influenced flock richness and size, although season did not. Flock composition also had changes related to fragment successional stage. Fragment geometry seems to be an important factor influencing flock structure and composition.

scholarly journals Variegated tropical landscapes conserve diverse dung beetle communities

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3125 ◽  
Author(s):  
Cristiane Costa ◽  
Victor Hugo F. Oliveira ◽  
Rafaella Maciel ◽  
Wallace Beiroz ◽  
Vanesca Korasaki ◽  
...  
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Canopy Cover ◽  
Dung Beetle ◽  
Dung Beetles ◽  
Forest Fragments ◽  
Forest Fragment ◽  
Natural Habitats ◽  
Vegetation Heterogeneity ◽  
Tropical Landscapes

BackgroundConserving biodiversity in tropical landscapes is a major challenge to scientists and conservationists. Current rates of deforestation, fragmentation, and land use intensification are producing variegated landscapes with undetermined values for the conservation of biological communities and ecosystem functioning. Here, we investigate the importance of tropical variegated landscapes to biodiversity conservation, using dung beetle as focal taxa.MethodsThe study was carried out in 12 variegated landscapes where dung beetles were sampled using six pitfall traps, 30 m apart from each other, along a transect in each studied landscape use and cover classes—LUCC (forest fragment and corridor, coffee plantation, and pasture). We baited each pitfall trap with 30 g of human feces and left open for a 48 h period. We also measured three environmental variables reflecting structural differences among the studied classes: canopy cover, local vegetation heterogeneity and soil sand content.ResultsWe collected 52 species and 2,695 individuals of dung beetles. We observed significant differences in the mean species richness, abundance and biomass among classes, with forest fragments presenting the highest values, forest corridors and coffee plantations presenting intermediate values, and pastures the lowest values. Regarding community structure, we also found significant differences among classes. Canopy cover was the only variable explaining variation in dung beetle species richness, abundance, biomass, and community structure. The relative importance of spatial turnover was greater than nestedness-resultant component in all studied landscapes.DiscussionThis study evaluated the ecological patterns of dung beetle communities in variegated tropical landscapes highlighting the importance of these landscapes for conservation of tropical biodiversity. However, we encourage variegation for the management of landscapes that have already been fragmented or as a complementary initiative of current conservation practices (e.g., protection of natural habitats and establishment of reserves).

Random placement models explain species richness and dissimilarity of frog assemblages within Atlantic Forest fragments

2022 ◽  
Author(s):  
Mauricio Almeida‐Gomes ◽  
Nicholas J. Gotelli ◽  
Carlos Frederico Duarte Rocha ◽  
Marcus Vinícius Vieira ◽  
Jayme Augusto Prevedello
Keyword(s):  
Species Richness ◽  
Atlantic Forest ◽  
Forest Fragments ◽  
Random Placement

scholarly journals Bird communities in three forest types in the Pernambuco Centre of Endemism, Alagoas, Brazil

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 ◽  
...  
Keyword(s):  
Species Richness ◽  
Bird Species ◽  
Bird Communities ◽  
Northeastern Brazil ◽  
Forest Fragments ◽  
Forest Types ◽  
Risk Of Extinction ◽  
Bird Fauna ◽  
Richness Patterns ◽  
Ombrophilous Forest

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.

scholarly journals The effect of fragmentation on spider richness (Arachnida: Araneae) in montane semideciduous seasonal forest

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Flávio Eduardo Vilas Boas Júnior ◽  
Amanda Da Silva Ferreira ◽  
Marcos Magalhães De Souza
Keyword(s):  
Species Richness ◽  
Atlantic Forest ◽  
Minas Gerais ◽  
Fragmentation Process ◽  
Natural Environments ◽  
Forest Fragments ◽  
Spider Species ◽  
Semideciduous Seasonal Forest ◽  
Agricultural Areas ◽  
Environmental Functions

The fragmentation process that has altered natural environments has been widely discussed, as it causes changes in communities and compromises different environmental functions. In this sense, this study was based on the evaluation of fragmentation on araneofauna of semideciduous seasonal forest fragments, phytophysiognomy belonging to the Atlantic Forest. The study was conducted in three fragments in the municipality of Inconfidentes, southern Minas Gerais, from April 2014 to March 2015. The results showed that there is a similarity in the composition of spider species among the sampled fragments and that the size of the fragment is positively correlated with species richness. Our data show that smaller fragments must be preserved and that agricultural areas maintain the integrity of adjacent forest areas to benefit from the predation dynamics that spiders exert on pests that affect plantations.

Temperature and vegetation complexity structure mixed-species flocks along a gradient of elevation in the tropical Andes

The Auk ◽  
2021 ◽  
Author(s):  
Flavia A Montaño-Centellas ◽  
Harrison H Jones
Keyword(s):  
Species Richness ◽  
Abiotic Stress ◽  
Environmental Gradients ◽  
Bird Community ◽  
Taxonomic Diversity ◽  
High Elevation ◽  
Tropical Andes ◽  
Mixed Species ◽  
Mixed Species Flocks ◽  
Species Flocks

Abstract Mixed-species flocks constitute community modules that can help test mechanisms driving changes to community composition across environmental gradients. Here, we examined elevational patterns of flock diversity (species richness, taxonomic diversity, species, and guild composition) and asked if these patterns were reflections of the full bird community at a given elevation (open-membership hypothesis), or if they were instead structured by environmental variables. We surveyed both the overall avian community and mixed-species flocks across an undisturbed elevational gradient (~1,350–3,550 m) in the Bolivian Andes. We then tested for the role of temperature (a surrogate for abiotic stress), resource diversity (arthropods, fruits), and foraging niche diversity (vegetation vertical complexity) in structuring these patterns. Patterns for the overall and flocking communities were similar, supporting our open-membership hypothesis that Andean flocks represent dynamic, unstructured aggregations. Membership openness and the resulting flock composition, however, also varied with elevation in response to temperature and vegetation complexity. We found a mid-elevation peak in flock species richness, size, and Shannon’s diversity at ~2,300 m. The transition of flocking behavior toward a more open-membership system at this elevation may explain a similar peak in the proportion of insectivores joining flocks. At high elevations, increasing abiotic stress and decreasing fruit diversity led more generalist, gregarious tanagers (Thraupidae) to join flocks, resulting in larger yet more even flocks alongside a loss of vegetation structure. At lower elevations, flock species richness increased with greater vegetation complexity, but a greater diversity of foraging niches resulted in flocks that were more segregated into separate canopy and understory sub-types. This segregation likely results from increased costs of interspecific competition and activity matching (i.e., constraints on movement and foraging rate) for insectivores. Mid-elevation flocks (~2,300 m) seemed, therefore, to benefit from both the open-membership composition of high-elevation flocks and the high vegetation complexity of mid- and low-elevation forests.

Consequences of Deforestation and Climate Change on Biodiversity

2011 ◽  
pp. 24-51 ◽  
Author(s):  
Roland Cochard
Keyword(s):  
Climate Change ◽  
Species Richness ◽  
Economic Valuation ◽  
Keystone Species ◽  
Forest Degradation ◽  
Habitat Destruction ◽  
Forest Fragments ◽  
Extinction Rates ◽  
Earth’S Climate ◽  
Species Extinctions

Ever since their evolution, forests have been interacting with the Earth’s climate. Species diversity is particularly high in forests of stable moist tropical climates, but patterns of diversity differ among various taxa. Species richness typically implies high ecosystem resilience to ecosystem disturbances; many species are present to fill in newly created niches and facilitate regeneration. Species loss, on the other hand, often entails environmental degradation and erosion of essential ecosystem services. Until now species extinction rates have been highest on tropical islands which are characterized by a high degree of species endemism but comparatively low species richness (and therefore high vulnerability to invasive species). Deforestation and forest degradation in many countries has lead to forest fragmentation with similar effects on increasingly insularized and vulnerable forest habitat patches. If forest fragments are becoming too small to support important keystone species, further extinctions may occur in cascading ways, and the vegetation structure and composition may eventually collapse. Until now relatively few reported cases of species extinctions can be directly attributed to climate change. However, climate change in combination with habitat destruction, degradation, and fragmentation may lead to new waves of species extinctions in the near future as species are set on the move but are unable to reach cooler refuges due to altered, obstructing landscapes. To mitigate the future risks of extinctions as well as climate change, major efforts should be undertaken to protect intact large areas of forests and restore wildlife corridors. Carbon sequestration may be seen as just one of many other environmental services of forest biodiversity that deserve economic valuation as alternatives to conversion to often unsustainable agricultural uses.

scholarly journals First standardized inventory of ants (Hymenoptera: Formicidae) in the natural grasslands of Paraná: New records for Southern Brazil

2018 ◽  
Vol 58 ◽  
pp. 12 ◽  
Author(s):  
Weslly Franco ◽  
Rodrigo Machado Feitosa
Keyword(s):  
Species Richness ◽  
New Records ◽  
Forest Fragments ◽  
Pitfall Traps ◽  
Southern Brazil ◽  
Conservation Units ◽  
Natural Grasslands ◽  
Taxonomic Novelties ◽  
First Time ◽  
Ant Diversity

Despite the large number of studies investigating ant diversity in Brazilian biomes, no ant-related studies have been carried out in Campos Gerais, a grassland physiognomy in Paraná state. The present study is the first inventory of the ant fauna in one of the few conservation units protecting the Campos Gerais landscape, the Guartelá State Park (PEG). Sixty samples were collected from different habitats within PEG using pitfall traps. Qualitative samples of leaf litter were collected from forest fragments and submitted to Winkler extractors. In addition, manual qualitative sampling was carried out in the various physiognomies within the PEG. A total of 163 species was collected and sorted into 43 genera and nine subfamilies. Five genera and 28 species were recorded for the first time in the state of Paraná. Out of these, 17 species were also recorded for the first time in the Southern Region of Brazil and two were recorded for the first time to the country. The significant species richness in the PEG and the high number of new records is a strong sign of this ecosystem’s potential to reveal taxonomic novelties. These results suggest that PEG, and the Campos Gerais as a whole, should be the target of greater conservation efforts to preserve native remnants.

Conservation value of koa (Acacia koa) reforestation areas on Hawaii Island

2018 ◽  
Vol 24 (1) ◽  
pp. 35
Author(s):  
Laurie Strommer ◽  
Sheila Conant
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Native Species ◽  
Canopy Cover ◽  
Basal Area ◽  
Forest Tree ◽  
Native Forest ◽  
Acacia Koa ◽  
Total Species Richness ◽  
Hawaii Island

Efforts to restore forests for ecological and economic benefit in Hawaii are converging on koa (Acacia koa), an endemic dominant or codominant canopy tree common across broad elevation and moisture gradients. We quantified plant species composition and forest structure in koa reforestation areas (KRAs) and in nearby intact native forest on Hawaii Island. Total species richness and percentage native species richness were lower in the plantation forests than in the intact forests, although species richness in the KRAs at one site was not significantly different from that in intact forest. Tree, sapling, and seedling densities differed between KRAs and forest sites at one site. At another, the native forest and one KRA had similar tree and seedling densities and similar canopy height and percentage canopy cover. Total stand basal area was greatest in the intact forest at both sites, although the basal area for the KRAs at one site exceeded those for intact forest at the other. Koa plantings can be structurally similar to intact forests though species composition differs. Our results suggest that koa forestry can facilitate native understorey development in some cases.

Regeneration of Quercus spp. along interactive forest boundaries in a fragmented peri-urban landscape of Mexico City

2019 ◽  
Vol 47 (1) ◽  
pp. 39-45
Author(s):  
Yilotl Cázares ◽  
Pablo M Vergara ◽  
Arturo García-Romero
Keyword(s):  
Mexico City ◽  
Urban Landscape ◽  
Canopy Cover ◽  
Tree Height ◽  
Suitable Habitat ◽  
Forest Fragments ◽  
Habitat Conditions ◽  
Edge Distance ◽  
The Matrix ◽  
Zero Inflated Poisson Models

SummaryBiodiversity conservation in forest fragments surrounded by a low-quality matrix requires an understanding of how ecological conditions prevailing in the matrix enter the fragments and interact with local habitat conditions. We assessed the regeneration of oak species along edge–interior gradients in forest fragments at the periphery of Mexico City. The abundance of oak saplings was sampled along transects to the forest, while the edge effect was analysed using segmented zero-inflated Poisson models for abundance data. Three oak species were dominant in terms of their relative abundances: Quercus laeta, Quercus castanea and Quercus obtusata. Regeneration of nine oak species responded nonlinearly to the edge distance, with greater sapling abundance from the edge up to 10 m into the fragment. Canopy cover and tree height decreased from edge to fragment interior, while saplings increased in open areas within the fragments (i.e., independent of edge distance). A posterior analysis indicated that Q. obtusata reacted positively to edges. These results indicate that oak regeneration is promoted by suitable habitat conditions near the boundaries. Therefore, we suggest that forest management should focus on promoting seed production and oak establishment in forest interior habitats.

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