Forest fragments, primary and secondary forests harbour similar arthropod assemblages after 40 years of landscape regeneration in the Central Amazon

Author(s):  
Karina Kethelen Silva De Aquino ◽  
Fabricio Beggiato Baccaro ◽  
Giulliana Appel ◽  
Augusto Loureiro Henriques ◽  
Paulo Estefano Dineli Bobrowiec ◽  
...  
CERNE ◽  
2017 ◽  
Vol 23 (3) ◽  
pp. 283-290
Author(s):  
Carlos Eduardo Gabriel Menezes ◽  
Roni Fernandes Guareschi ◽  
Marcos Gervasio Pereira ◽  
Lúcia Helena Cunha Anjos ◽  
Maria Elizabeth Fernandes Correia ◽  
...  

ABSTRACT The objective of this study was to evaluate the soil carbon stock (Stock C) and bulk density, the chemical and granulometric fractions of the organic matter and the isotopic signal of the soil δ13C in forest fragments and a mixed managed pasture (MMP). The study was carried out in the municipality of Pinheiral, State of Rio de Janeiro. The evaluated areas were: fragment of secondary forest in initial stage (SFIS) with 20 years of regeneration; fragment of secondary forest in intermediate stage (SFINS), with 25 years of regeneration; advanced secondary forest fragment (SFAS) with 60 years of regeneration and mixed pasture managed (MHP). The attributes related to soil carbon showed significant responses to the effects of land degradation / recovery processes, especially for the following indicators: total organic carbon, organic matter stock and particulate organic matter. No significant alterations for humic substances, and prevalence of the humin fraction was found. The most significant changes in δ13C values occurred up to the depth of 60 cm. In the grassland area, at 0-10 cm, 67% of the carbon stock comes from C4 plants, reducing in the subsequent layers. In SFINS and SFAS areas, at 0-10 cm, the contribution of C3 plants was significant, with minor changes in depth.


2019 ◽  
Author(s):  
Nohemi Huanca Nuñez ◽  
Robin L. Chazdon ◽  
Sabrina E. Russo

AbstractRegeneration of tropical secondary forests depends critically on seed input, and yet successional dynamics of seed dispersal remain poorly understood. We investigated the role of stochastic vs. deterministic processes in structuring seed rain in successional forests using four years of seed rain data collected at two time periods in four tropical secondary forest fragments representing a chronosequence and in mature forest. Determinism in successional trajectories is defined as predictable, directional, and orderly changes in community structure through time, resulting in convergence toward a climax community. We found that with increasing successional age, the community assembly of the seed rain in secondary forests became more deterministic, and community structure converged to that in the mature forest, both in terms of taxonomic and functional composition. Taxonomic similarity of the seed rain in successional forest to that of the mature forest increased with successional age, as did species co-occurrence and the percentage of shared species between the seed rain of successional and mature forests. The proportions of large, shade-tolerant species in the seed rain increased with successional age, although the proportion of animal-dispersed species increased only modestly. Analyses of the spatial variation in community structure in the seed rain among sites within each secondary forest showed evidence that assembly processes transitioned from being deterministic and convergent early on, to purely stochastic, and then to deterministic and divergent later in succession. Moreover, with increasing successional age, the composition of the seed rain became more similar to that of the mature woody stems in the forest, which could be an important deterministic driver of successional change, that, along with among site variation in landscape context and environment, could also generate idiosyncratic successional patterns among secondary forest fragments Our results suggest that the dominant processes influencing seed dispersal and assembly of the seed rain change during succession and point to successional feedbacks influencing the seed rain that are likely to shape regeneration trajectories.


2020 ◽  
Vol 11 (7) ◽  
pp. 1-15
Author(s):  
Fernado Silva Coutinho ◽  
Luiz Alberto da Silva Rodrigues Pinto ◽  
Marcos Gervasio Pereira ◽  
Shirlei Almeida Assunção ◽  
Silver Rodrigues Zandoná ◽  
...  

The southeast region of Brazil, in the Atlantic Forest biome, has been impacted for a long time, observing today small agricultural areas inserted in a matrix of pastures and forest fragments, the soils being highly modified due to the different forms of use they were submitted. The objective of this study was to evaluate the organic carbon content in the humic fractions on soil organic matter (SOM), the distribution of aggregates in size classes and the porosity and aggregates density variables by means of computed tomography in secondary forest, pasture and agriculture areas in Pinheiral (RJ). Three areas composed of secondary forests with different succession stages and three managed areas were evaluated: Secondary Forest (SF) Initial Stage (SFIS), Medium Stage (SFMS), Advanced Stage (SFAS), mixed managed pasture (MMP), and perennial and annual agriculture (PA and AA, respectively). Three types of samples were collected in different layers: i) deformed samples to quantify carbon in the SOM humic fractions; ii) clods for quantifying the mass of aggregates and later assessing the distribution by diameter classes; and iii) undisturbed samples collected with the aid of an acrylic cylinder to perform computed tomography (CT). Humic substances and aggregate classes below 2.0 mm were the attributes most influenced by the forms of use and/or vegetation cover. The CT technique proved to be efficient in the measurement of the edaphic attribute’s porosity and density of the aggregates, helping in the characterization and separation of the different environments.


2012 ◽  
Vol 28 (4) ◽  
pp. 331-341 ◽  
Author(s):  
Katerina Tvardikova ◽  
Vojtech Novotny

Abstract:Although predation is generally seen as one of the key factors determining the abundance and composition of insect herbivore communities in tropical rain forests, quantitative estimates of predation pressure in rain-forest habitats remain rare. We compared incidence of attacks of different natural enemies on semi-concealed and exposed caterpillars (Lepidoptera) in lowland and montane tropical rain forests, using plasticine models of caterpillars. We recorded attacks on caterpillars in four habitats: primary forest, secondary forest and forest fragment in lowlands (200 m asl), and montane primary forest (1700 m asl). We used 300 exposed and 300 semi-concealed caterpillars daily, and conducted the experiment for 6 d in every habitat. Daily incidence of attacks was higher on exposed caterpillars (4.95%) than on semi-concealed (leaf-rolling) caterpillars (2.99%). Attack pressure of natural enemies differed also among habitats. In the lowlands, continuous primary and secondary forests had similar daily incidence of attacks (2.39% and 2.36%) which was however lower than that found in a primary forest fragment (4.62%). This difference was caused by higher incidence of attacks by birds, ants and wasps in the forest fragment. The most important predators were birds in montane rain forests (61.9% of identified attacks), but insect predators, mostly ants, in the lowlands (58.3% of identified attacks). These results suggest that rapid decrease in the abundance of ants with altitude may be compensated by increased importance of birds as predators in montane forests. Further, it suggests that small rain-forest fragments may suffer from disproportionately high pressure from natural enemies, with potentially serious consequences for survival of their herbivorous communities.


2006 ◽  
Vol 66 (4) ◽  
pp. 999-1020 ◽  
Author(s):  
E. Franklin ◽  
E. M. R. Santos ◽  
M. I. C. Albuquerque

We are summarizing the current state of knowledge of the diversity and distribution of oribatid mites in 26 environments in northern Brazil and of a rain forest in Peru. the published studies were mostly concentrated in central amazon. Only one report is a result from an agricultural polyculture. We are providing the first lists of species for savannas and for the brazilian states of Roraima and Pará. up to date, 146 species are definitively identified from a total of 444 taxa with 188 known genera, reinforcing the notion of a rich biodiverse area. the high number of 298 non-described species (morphospecies) clearly shows the inadequacy of the current taxonomic knowledge for the region. most of the registers are from forest environments. in the soil from primary forests, we registered the highest diversity (54-155 species/morphospecies). eighty-nine species were unique to primary forests, followed by 34 for savannas, 32 in trees, 10 in "igapó", 4 in caatinga, 3 in secondary forests, two in "várzea" and one in polyculture. twenty genera were the most speciose. the species with the largest home ranges were Rostrozetes foveolatus, Scheloribates sp. a, and Galumna sp. a. our numbers reflect the lack of taxonomists and show that the taxonomic knowledge must be improved for the region or we will continue to work with taxonomic resolution of order or family and a high percentage of morphospecies, which will probably be appropriate to the question being asked in each study, but not for a comparison among environments.


2017 ◽  
Vol 28 (2) ◽  
pp. 302-318 ◽  
Author(s):  
CLAUDIA HERMES ◽  
JEROEN JANSEN ◽  
H. MARTIN SCHAEFER

SummaryThe Chocó-Tumbesian region of western Ecuador is one of the 25 global biodiversity hotspots harbouring high numbers of endemic species, which are heavily threatened by habitat loss and fragmentation. Moreover, ongoing climate change in the tropics drives species uphill as lower-lying areas are becoming constantly drier. Such upslope movement can pose major challenges for less mobile species, such as understorey birds which are confined to mature forests and unable to cross habitat gaps. Consequently, these species are threatened by a combination of upslope range shifts and forest fragmentation. In our study, we investigated population numbers and habitat requirements of the Ecuadorian Tapaculo Scytalopus robbinsi, which is endemic to the premontane cloud forests of south-western Ecuador. Comparing the microhabitat structure within territories with control sites revealed that Ecuadorian Tapaculos prefer old secondary forests. Moreover, connectivity between forest fragments was the strongest predictor of the presence of territories within them. We estimated the mean upslope shift of the distribution range as 100 m per decade and developed a model of habitat availability for the revised range. Extrapolating the number of territories from the study area to the distributional range of the Ecuadorian Tapaculo showed that the global population size is smaller than previously assumed. Our results suggest that the Ecuadorian Tapaculo is strongly affected by forest loss and degradation. Therefore, to prevent a continuing decline in population numbers or even extinction, conservation measures focusing on restoring connectivity between fragments and increasing habitat quality and quantity for the remaining populations need to be prioritised.


2020 ◽  
Vol 50 (2) ◽  
pp. 124-132
Author(s):  
Igor DO VALE ◽  
Izildinha Souza MIRANDA ◽  
Danielle MITJA ◽  
Alessio Moreira SANTOS ◽  
Graciliano Galdino Alves dos SANTOS ◽  
...  

ABSTRACT Shade-tolerant forest species are among the most susceptible to habitat loss in agricultural mosaics, where a variety of croplands is connected to forests at different levels of anthropogenic disturbance. We aimed to evaluate the community similarity of shade-tolerant species among different land use types across agricultural mosaics with different levels of disturbance. The study was conducted in three municipalities in southern and southeastern Pará state, in eastern Amazonia. A multiple-community similarity measure based on the Horn similarity index was used to compare land use types and assess the resilience of shade-tolerant species towards forest loss and disturbance at the landscape level. High shade-tolerant species similarity was found between mature forest fragments that underwent different levels of disturbance in all three agricultural mosaics, but secondary forests had lower similarity with mature forest in the most fragmented and altered mosaic. Shade-tolerant species showed very low density in croplands, but the same group of species seemed to colonize agricultural fields of annual crops and clean pasture, as they showed high community similarity. Another group of species was present in invaded pastures, probably due to the effects of time since land abandonment after woody species colonization. Mixed tree plantations were more similar to mature and secondary forests than other types of croplands. Shade-tolerant species similarity was higher among land use types inserted in agricultural landscapes that maintained conserved forest fragments. Our results suggest that the conservation of mature forests and landscape connectivity are crucial to the maintenance of shade-tolerant species in agricultural mosaics.


2017 ◽  
Vol 66 (1) ◽  
pp. 394 ◽  
Author(s):  
Oscar Pérez-García ◽  
Tamara J. Benjamin ◽  
Diego Enrique Tobar

Land use change by the intensification of agriculture contributes to tropical forest fragmentation and biodiversity loss. In this sense, in comparison with traditional agroforestry systems (AFS), modern AFS are considered irrelevant for the conservation of biodiversity of tropical forest fragments. However, there is an increasing trend toward the establishment of different types of modern AFS. Owing to the sensitivity to environmental changes, we evaluated the biodiversity of butterflies in AFS with Coffea arabica and Erythrina poeppigiana (CP), and intermixed with Musa spp. (CPM) or Cordia alliodora (the only native species of AFS) (CPL), as well as premontane very humid forest fragments in the Volcánica Central-Talamanca Biological Corridor, Costa Rica. In six representative sites of each system we set up three parallel 80 m line-transects, separated by a distance of 25 m. Each coffee farm and forest fragment (FR) was surveyed during 1.5 hours to record butterflies. All sites were sampled once a month from May to July 2007. We obtained 4.5 hours of sampling/site, and 27 hours of sampling/habitat. Both CP and CPM together had a butterflies’ species composition which differed from CPL and FR. The indicator species of both CP and CPM together were Hermeuptychia hermes and Anartia jatrophae which are typical of open areas. CPL resulted with the species of secondary forests Heliconius erato petiverana and Pareuptychia ocirrhoe as indicators. In contrast, FR resulted with several indicator species typical of closed canopy forests such as Pierella helvina incanescens, Caligo eurilochus, and Morpho peleides limpida. Moreover, the richness of species was similar among coffee AFS. Furthermore, the richness of species of each coffee AFS was lower in comparison with FR. However, among coffee AFS, CPL harbored higher diversity (Exp(H’)) of forest butterflies than CP. Also, CPM was higher in abundance of frugivorous butterflies in relation with CP and CPL. In fragmented forests, coffee farms with exotic shade species combined at least with a native tree or fruit species, can be a better habitat for forest butterflies than those dominated by an exotic monospecific shade.


Author(s):  
B.R. FORSBERG, ◽  
M. GASTIL, ◽  
S.K. HAMILTON, ◽  
L.L. HESS, ◽  
I.B.T. LIMA, ◽  
...  
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