scholarly journals Determinism and stochasticity in seed dispersal-successional feedbacks

2019 ◽  
Author(s):  
Nohemi Huanca Nuñez ◽  
Robin L. Chazdon ◽  
Sabrina E. Russo
Keyword(s):  
Community Structure ◽  
Seed Dispersal ◽  
Secondary Forest ◽  
Seed Rain ◽  
Secondary Forests ◽  
Forest Fragments ◽  
Mature Forest ◽  
Site Variation ◽  
Tropical Secondary Forest ◽  
Successional Age

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.

Changes in seed rain during secondary succession in a tropical montane cloud forest region in Oaxaca, Mexico

2008 ◽  
Vol 24 (4) ◽  
pp. 433-444 ◽  
Author(s):  
R. F. del Castillo ◽  
M. A. Pérez Ríos
Keyword(s):  
Seed Dispersal ◽  
Secondary Succession ◽  
Cloud Forest ◽  
Seed Rain ◽  
Stand Age ◽  
Primary Forest ◽  
Forest Fragments ◽  
Long Distance ◽  
Southern Mexico ◽  
Tropical Montane Cloud Forests

AbstractSeed dispersal is the first stage of colonization, and potentially affects recruitment. This process deserves more attention in tropical montane cloud forests (TMCF), since secondary succession is common owing to episodic disturbances. We studied annual seed rain in 10 nearby forest stands, ≈7 to ≈100 y following shifting agriculture, and one primary forest stand in southern Mexico to test the hypothesis that seed rain is limited at the scale of neighbouring fragments and that such limitation differs among species with different dispersal modes and successional origin. Annual seed rain was heterogeneous among forest fragments probably due to the prevalence of local seed dispersal, differences in stand age and the proportion of zoochory, and may help explain the patchy distribution of species observed in TMCF. Seed rain abundance and species diversity per unit trap area increased with the age of the stand. Biotically dispersed seeds increased towards older stands relative to abiotically dispersed seeds. Late-successional seeds were rarer in early successional stands than pioneer seeds in late-successional stands, suggesting that long-distance dispersal is generally more common for pioneer plants. Seed dispersal appears to constrain forest regeneration and to influence fragment species composition as a function of the distance from the source forests.

scholarly journals ORGANIC MATTER IN AREAS UNDER SECONDARY FORESTS AND PASTURE

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 ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Carbon ◽  
Carbon Stock ◽  
Secondary Forest ◽  
Intermediate Stage ◽  
C3 Plants ◽  
Secondary Forests ◽  
Forest Fragments ◽  
Forest Fragment ◽  
Soil Carbon Stock

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.

scholarly journals Soil quality indicators in areas with different vegetation cover in the Atlantic Forest biome, Southeastern Brazil

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 ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Atlantic Forest ◽  
Vegetation Cover ◽  
Secondary Forest ◽  
Southeastern Brazil ◽  
Organic Carbon Content ◽  
Secondary Forests ◽  
Forest Fragments ◽  
Humic Fractions ◽  
Forest Biome

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.

Predation on exposed and leaf-rolling artificial caterpillars in tropical forests of Papua New Guinea

2012 ◽  
Vol 28 (4) ◽  
pp. 331-341 ◽  
Author(s):  
Katerina Tvardikova ◽  
Vojtech Novotny
Keyword(s):  
Natural Enemies ◽  
Rain Forest ◽  
Secondary Forest ◽  
Primary Forest ◽  
Secondary Forests ◽  
Forest Fragments ◽  
Leaf Rolling ◽  
Forest Fragment ◽  
Tropical Rain Forests ◽  
Rain Forests

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.

Seed rain in a tropical agricultural landscape

2009 ◽  
Vol 25 (5) ◽  
pp. 541-550 ◽  
Author(s):  
Cristina Martínez-Garza ◽  
Alejandro Flores-Palacios ◽  
Marines De La Peña-Domene ◽  
Henry F. Howe
Keyword(s):  
Agricultural Landscape ◽  
Forest Type ◽  
Secondary Forest ◽  
Woody Species ◽  
Seed Rain ◽  
Secondary Forests ◽  
Old Growth Forest ◽  
Forest Remnants ◽  
Successional Species ◽  
Total Seed

Abstract:Seed dispersal into fragmented tropical landscapes limits the rate and character of ecological succession between forest remnants. In a novel experiment in recovery of dispersal between forest remnants, 120 1-m2 seed traps were placed in fenced plots in active pasture 90–250 m from forest, and in nearby primary and secondary forests. Total seed rain from December 2006 to January 2008 included 69 135 seeds of 57 woody species. High richness of seed rain of early-successional trees occurred in all habitats, but seed rain of late-successional woody plants was much lower into pastures and secondary forest than into old-growth forest. Non-metric ordination analysis further demonstrated high movement of late-successional species within and between forest and secondary forest, but little movement of species of either forest type to pastures. Most species were dispersed by animals, but most seeds were dispersed by wind. A pattern of seed rain biased strongly towards wind-dispersed species creates a template for regeneration quite unlike that in nearby forest.

scholarly journals Allometric equations to estimate the above-ground biomass of trees in the tropical secondary forests of different ages

2019 ◽  
Vol 20 (9) ◽  
Author(s):  
Karyati Karyati ◽  
ISA B. IPOR ◽  
ISMAIL JUSOH ◽  
MOHD. EFFENDI WASLI
Keyword(s):  
Secondary Forest ◽  
Floristic Composition ◽  
Allometric Equations ◽  
Secondary Forests ◽  
Strong Correlations ◽  
Above Ground Biomass ◽  
Ground Biomass ◽  
Dry Biomass ◽  
Different Ages ◽  
Tropical Secondary Forest

Abstract. Karyati, Ipor IB, Jusoh I, Wasli ME. 2019. Allometric equations to estimate the above-ground biomass of trees in the tropical secondary forests of different ages. Biodiversitas 20: 2427-2436. The allometric equations for trees of secondary forests of different ages in abandoned lands after shifting cultivation are still rarely available. The objective of this study was to develop allometric equations to estimate the above-ground biomass (AGB) of trees (DBH of > 5 cm) in the tropical secondary forest of different ages, namely 5, 10, and 20 years after abandonment. The selected trees in this study represented the dominant and rare species and DBH classes in each study site. The trunk dry biomass and AGB showed strong correlations (adjusted R2= 0.59-0.95) with diameter at breast height (DBH) and height. The leaf and branch dry biomass had weak correlations with height (adjusted R2=0.36-0.50). The developed allometric equations were suitable for trees of secondary forests of different ages, because the selected samples used in the destructive method were based on a field inventory data of forest structure and floristic composition.

The Recovery of Biomass, Nutrient Stocks, and Deep-Soil Functions in Secondary Forests

2001 ◽  
Author(s):  
Daniel Nepstad ◽  
Paulo R. S. Moutinho
Keyword(s):  
Secondary Forest ◽  
Biomass Accumulation ◽  
Root Systems ◽  
Agricultural Landscapes ◽  
Forest Recovery ◽  
Secondary Forests ◽  
Forest Development ◽  
Mature Forest ◽  
Forest Remnants ◽  
Conceptual Shift

Secondary forests cover approximately one third of the 0.5 million km2 of the Brazilian Amazon that have been cleared for agriculture (Houghton et al. 2000, Fearnside and Guimarães 1996). These forests counteract many of the deleterious impacts of forest conversion to agriculture and cattle pasture. They absorb carbon from the atmosphere, they reestablish hydrological functions performed by mature forests, and they reduce the flammability of agricultural landscapes. Secondary forests transfer nutrients from the soil to living biomass, thereby reducing the potential losses of nutrients from the land through leaching and erosion. They also allow the expansion of native plant and animal populations from mature forest remnants back into agricultural landscapes. The study of forest recovery has focused on aboveground processes, primarily biomass accumulation. The few studies that have examined the recovery of belowground functions in Amazon secondary forests have been restricted to the upper meter or less of soil (e.g. Buschbacher et al. 1988). A review of our knowledge of secondary forest recovery is needed that incorporates accumulating evidence that approximately half of the region’s forests rely upon root systems extending to depths of several meters to maintain evapotranspiration during prolonged seasonal drought (Nepstad et al. 1994, Jipp et al. 1998, Nepstad et al. 1999a, Hodnett et al. 1997; see also Richter and Markewitz 1995). This discovery demands a conceptual shift in our approach to forest recovery on abandoned land. Are secondary forests capable of regrowing deep root systems, thereby recovering hydrologic functions and fire resistance of the mature forest? At what rate does this recovery take place? How does this ability to tap a large soil volume change our thinking about the role that nutrient shortages play in restricting secondary forest recovery? In this chapter, we begin to address these questions with the goal of furthering a mechanistic understanding of forest recovery on abandoned Amazonian lands. Our analysis focuses on three measures of secondary forest development: biomass accumulation, nutrient accumulation, and hydrological recovery. We choose biomass accumulation, because it is the best integrative measure of secondary forest development, it is the basis for estimates of carbon sequestration by secondary forests, and it is the most frequently measured secondary forest parameter.

Seed rain during initial colonization of abandoned pastures in the premontane wet forest zone of southern Costa Rica

2007 ◽  
Vol 23 (2) ◽  
pp. 151-159 ◽  
Author(s):  
Jerald J. Dosch ◽  
Chris J. Peterson ◽  
Bruce L. Haines
Keyword(s):  
Costa Rica ◽  
Woody Plant ◽  
Seed Rain ◽  
Forest Fragments ◽  
Wet Season ◽  
Forest Zone ◽  
Site Variation ◽  
Successional Trajectory ◽  
Total Seed ◽  
Insight Into

Understanding tropical succession requires insight into propagule availability, which constrains possible woody plant recruitment, yet seed rain composition in multiple post-agricultural sites has seldom been examined. We monitored seed rain for 60 wk in five abandoned pastures in southern Costa Rica, collecting a total of 1 140 688 seeds of 165 morphospecies. Most seeds (80.1%) arrived during the wet season. Species richness was highest in the wet season and greater in forest than in pasture. Seed rain density was greatest at the forest/pasture edge and decreased drastically just a few metres into pastures. In and near the forest, animal-dispersed seeds were more abundant than seeds dispersed by other means, while wind-dispersed taxa increased in relative importance at greater distances from the forest. Total seed input to pastures did not reflect size of adjacent forest fragments, although seed rain density varied more than threefold among sites. Among-site variation in density of regenerating woody seedlings was roughly proportional to among-site variation in seed rain. Morphospecies composition differed significantly among sites. Also, seed rain and woody plant colonists were rather dissimilar in composition, suggesting that while propagule availability is necessary for early woody plant establishment, it is a poor predictor of successional trajectory.

The Contribution of Tropical Secondary Forest Fragments to the Conservation of Fruit-feeding Butterflies: Effects of Isolation and Age

2005 ◽  
Vol 14 (14) ◽  
pp. 3577-3592 ◽  
Author(s):  
Dorthe Veddeler ◽  
Christian H. Schulze ◽  
Ingolf Steffan-Dewenter ◽  
Damayanti Buchori ◽  
Teja Tscharntke
Keyword(s):  
Secondary Forest ◽  
Forest Fragments ◽  
Tropical Secondary Forest

scholarly journals Lichen community structure and richness in three mid-elevation secondary forests in Costa Rica

2021 ◽  
Vol 69 (2) ◽  
pp. 688-699
Author(s):  
Roberto A. Cordero S. ◽  
Ana Garrido ◽  
Junior Pastor Pérez-Molina ◽  
Óscar Ramírez-Alán ◽  
José Luis Chávez
Keyword(s):  
Community Structure ◽  
Costa Rica ◽  
Secondary Forest ◽  
Lichen Species ◽  
Homogeneity Test ◽  
Secondary Forests ◽  
Tree Plantation ◽  
Lichen Community ◽  
Passive Restoration ◽  
Ecological Importance

Introduction: Lichen diversity, community structure, composition and species abundance have been used as indicators of the integrity and ecological continuity of tropical forest ecosystems. Objectives: To assess corticolous lichen species composition, diversity, and ecological importance of three forested stands differing in time of abandonment as indicators of how passive restoration influences the lichen community assemblage. Methods: We surveyed individual lichens on tree stems of a reference old secondary forest and a young secondary forest (50 and 14-year-old natural regeneration after pasture abandonment, respectively), and in a 35-year-old exotic cypress tree plantation, in the oriental Central Valley, in Orosí, Costa Rica. Standard diversity, similarity indexes, and the importance value index were calculated. An NMDS analysis was performed on the community structure parameters and in a presence-absence matrix. Results: We found 64 lichen species in 25 families with 42, 21, and 23 species, and 20, 10, and 15 families, in the young and old secondary forests, and the cypress plantation, respectively. Cryptothecia sp. possessed the highest importance across sites. More than 87 % of the species are rare. The combined IVI of the top three families were: 36, 48.5, and 74.8 % in the young and old forests and the Cypress plantation sites, respectively. Overall, Arthoniaceae is in the top three families. The young forest had the highest species richness, but the old forest presented the best evenness. Similarity and diversity indexes suggest a particularly low resemblance in the lichen communities but a smooth gradient differentiation between the three forests, which was confirmed by the NMDS test. The homogeneity test identified great differences in ecological importance and composition. Conclusions: This region contains a distinctive assemblage of species resulting in a strong community differentiation by site, reflecting the influence of ecophysiological and microclimatic factors that define lichen establishment and survival and suggesting a great regional beta diversity, within a fragmented landscape. Greater connectivity and passive restoration strategies resulted in greater diversity and a more heterogeneous community structure on both forests than the corticolous community of the abandoned plantation. Protection of forest fragments will maximize the integrity of future forests.

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