Holocene Flooding and Species Diversity in Southwestern Amazonia

1984 ◽  
Vol 21 (3) ◽  
pp. 369-375 ◽  
Author(s):  
Kenneth E. Campbell ◽  
David Frailey
Keyword(s):  
Species Diversity ◽  
Amazon Basin ◽  
Erosion And Deposition ◽  
Pleistocene Refugia ◽  
Seasonal Flooding ◽  
Southwestern Amazonia ◽  
Geologic Data ◽  
Lowland Amazonia

A thick blanket of Holocene alluvium lies over southwestern lowland Amazonia, and may possibly occur throughout much of the Amazon Basin. These deposits resulted from massive, seasonal flooding from about 11,000 to about 5000 yr B.P. that was followed by two cycles of erosion and deposition. Interpretations based on these geologic data suggest that southwestern lowland Amazonia is ecologically an “island” in a state of supersaturated disequilibrium as a result of colonization from Pleistocene refugia on its perimeter, and that habitats of highest diversity may be the most recent in origin. Conservation efforts and studies of Amazonian biogeography, soils, and paleoethnography should be reevaluated in light of the geologic data.

scholarly journals Evaluating the effect of nutrient redistribution by animals on the phosphorus cycle of lowland Amazonia

2018 ◽  
Vol 15 (1) ◽  
pp. 279-295 ◽  
Author(s):  
Corina Buendía ◽  
Axel Kleidon ◽  
Stefano Manzoni ◽  
Björn Reu ◽  
Amilcare Porporato
Keyword(s):  
Amazon Basin ◽  
P Availability ◽  
Phosphorus Cycle ◽  
Terra Firme ◽  
The Andes ◽  
P Content ◽  
Spatial Redistribution ◽  
Soil Age ◽  
Seasonally Flooded ◽  
Lowland Amazonia

Abstract. Phosphorus (P) availability decreases with soil age and potentially limits the productivity of ecosystems growing on old and weathered soils. Despite growing on ancient soils, ecosystems of lowland Amazonia are highly productive and are among the most biodiverse on Earth. P eroded and weathered in the Andes is transported by the rivers and deposited in floodplains of the lowland Amazon basin creating hotspots of P fertility. We hypothesize that animals feeding on vegetation and detritus in these hotspots may redistribute P to P-depleted areas, thus contributing to dissipate the P gradient across the landscape. Using a mathematical model, we show that animal-driven spatial redistribution of P from rivers to land and from seasonally flooded to terra firme (upland) ecosystems may sustain the P cycle of Amazonian lowlands. Our results show how P imported to land by terrestrial piscivores in combination with spatial redistribution of herbivores and detritivores can significantly enhance the P content in terra firme ecosystems, thereby highlighting the importance of food webs for the biogeochemical cycling of Amazonia.

scholarly journals Phytogeographic support tor the theory of Pleistocene forest refuges in the Amazon Basin, based on evidence from distribution patterns in Caryocaraceae, Chrysobalanaceae, Dichapetalaceae and Lecythidaceae

1973 ◽  
Vol 3 (3) ◽  
pp. 5-26 ◽  
Author(s):  
Ghillean T. Prance
Keyword(s):  
Species Diversity ◽  
Amazon Basin ◽  
Forest Cover ◽  
Woody Plant ◽  
Distribution Patterns ◽  
Genetic Isolation ◽  
Lowland Forest ◽  
Previous Evidence ◽  
Plant Families ◽  
Refuge Areas

Abstract In recent years it has generally been accepted that Amazonia was subject to long dry periods in the late Pleistocene and post-Pleistocene which induced forest cover to a few limited areas or refuges. It has been proposed that the subsequent genetic isolation into separate populations is a mnjor factor in the evolution of the species diversity within the lowland forest of Amazonia. Most of the previous evidence for this theory is based on studies of animals, for example: lizards, butterflies, and birds. Here data are presented to confirm the theory of forest refuges using evidence from phytogeography. Distribution patterns of the lowland species of the woody plant families Caryocaraceae, Chrysobalanaceae, Dichapetalaceae and Lecythidaceae are discussed and concur with the possibility of forest refuges. A map is given of the refuge areas that seem most likely, based on evidence from species distribution of the above plant families. The refuges proposed here correspond closely with the refuge areas proposed by Haffer and Brown rather than the extremely reduced areas proposed by Vanzolini.

scholarly journals Effect of seasonal flooding cycle on litterfall production in alluvial rainforest on the middle Xingu River (Amazon basin, Brazil)

2015 ◽  
Vol 75 (3 suppl 1) ◽  
pp. 250-256 ◽  
Author(s):  
M. Camargo ◽  
T. Giarrizzo ◽  
AJS. Jesus
Keyword(s):  
Seasonal Variation ◽  
Annual Cycle ◽  
Amazon Basin ◽  
General Pattern ◽  
Tropical Ecosystems ◽  
Seasonal Flooding ◽  
Xingu River ◽  
Litterfall Production ◽  
Flooded Forests ◽  
Inverse Pattern

Abstract The assumption for this study was that litterfall in floodplain environments of the middle Xingu river follows a pattern of seasonal variation. According to this view, litterfall production (total and fractions) was estimated in four alluvial rainforest sites on the middle Xingu River over an annual cycle, and examined the effect of seasonal flooding cycle. The sites included two marginal flooded forests of insular lakes (Ilha Grande and Pimentel) and two flooded forests on the banks of the Xingu itself (Boa Esperança and Arroz Cru). Total litterfall correlated with rainfall and river levels, but whereas the leaf and fruit fractions followed this general pattern, the flower fraction presented an inverse pattern, peaking in the dry season. The litterfall patterns recorded in the present study were consistent with those recorded at other Amazonian sites, and in some other tropical ecosystems.

scholarly journals High levels of cryptic species diversity uncovered in Amazonian frogs

2011 ◽  
Vol 279 (1734) ◽  
pp. 1806-1814 ◽  
Author(s):  
W. Chris Funk ◽  
Marcel Caminer ◽  
Santiago R. Ron
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Cryptic Species ◽  
Amazon Basin ◽  
Nuclear Dna ◽  
Cryptic Diversity ◽  
Undescribed Species ◽  
Tropical Regions ◽  
The Poor ◽  
Poor Understanding

One of the greatest challenges for biodiversity conservation is the poor understanding of species diversity. Molecular methods have dramatically improved our ability to uncover cryptic species, but the magnitude of cryptic diversity remains unknown, particularly in diverse tropical regions such as the Amazon Basin. Uncovering cryptic diversity in amphibians is particularly pressing because amphibians are going extinct globally at an alarming rate. Here, we use an integrative analysis of two independent Amazonian frog clades, Engystomops toadlets and Hypsiboas treefrogs, to test whether species richness is underestimated and, if so, by how much. We sampled intensively in six countries with a focus in Ecuador ( Engystomops : 252 individuals from 36 localities; Hypsiboas : 208 individuals from 65 localities) and combined mitochondrial DNA, nuclear DNA, morphological, and bioacoustic data to detect cryptic species. We found that in both clades, species richness was severely underestimated, with more undescribed species than described species. In Engystomops , the two currently recognized species are actually five to seven species (a 150–250% increase in species richness); in Hypsiboas , two recognized species represent six to nine species (a 200–350% increase). Our results suggest that Amazonian frog biodiversity is much more severely underestimated than previously thought.

scholarly journals Fishes from the Lower Urubamba river near Sepahua, Amazon Basin, Peru

Check List ◽  
2011 ◽  
Vol 7 (4) ◽  
pp. 413 ◽  
Author(s):  
Tiago P. Carvalho ◽  
Jéssica Espino ◽  
Emmanuel Máxime ◽  
Roberto Quispe ◽  
Blanca Rengifo ◽  
...  
Keyword(s):  
Amazon Basin ◽  
Fish Fauna ◽  
Single Species ◽  
Peruvian Andes ◽  
Diverse Families ◽  
Madre De Dios ◽  
The Town ◽  
Lowland Amazonia

We report results of an ichthyological survey of the Lower Urubamba river, a tributary of the Ucayali river located in the southwestern portion of the Amazon Basin in southeastern Peru. Collections were made at low water (July, 2009) from 280 - 310 m elevation, near the town of Sepahua within the Fitzcarrald Arch, an upland associated with Pliocene (c. 4 Ma) uplift of the Peruvian Andes. This is the second of four planned expeditions to the region with the goal of comparing ichthyofaunas across the headwaters of the largest tributary basins in the western Amazon (Juruá, Ucayali, Purús and Madre de Dios). Twenty-one sites were sampled using seine nets, hook lines, cast nets and dip nets. A total of 98 species in 22 families and eight orders were captured and identified. The most diverse families are Characidae (40 spp.) and Loricariidae (20 spp.), and 12 families are represented by a single species. These data suggest that the fish fauna of the Lower Urubamba river near Sepahua is distinct from, and less diverse than, adjacent areas of lowland Amazonia. 

LBA-ECO LC-07 MONTHLY MEAN FLOODED WETLANDS HABITAT, CENTRAL AMAZON BASIN: 1979-1996

2011 ◽  
Author(s):  
B.R. FORSBERG, ◽  
M. GASTIL, ◽  
S.K. HAMILTON, ◽  
L.L. HESS, ◽  
I.B.T. LIMA, ◽  
...  
Keyword(s):  
Amazon Basin ◽  
Central Amazon

Diatoms in the Early Valdai (Weichselian) sediments in Lake Ladoga basin

2019 ◽  
pp. 225-228
Author(s):  
Anna V. Ludikova
Keyword(s):  
Species Diversity ◽  
High Energy ◽  
Lake Ladoga ◽  
Diatom Assemblages ◽  
Marine Diatoms ◽  
Selective Preservation

The pioneer diatom study of the Early Weichselian (Valdai) sediments in Lake Ladoga basin was performed. The specifics of the diatom assemblages (co-occurrence of ecologically incompatible taxa, poor species diversity, low diatom concentration and selective preservation) suggest that during the Early Weichselian time intense erosion of previously deposited marine Eemian (Mikulino) sediments prevailed, which resulted in re-deposition of marine diatoms. The sedimentation took place in high-energy environments unfavorable for diatom accumulation and preservation.

The Amazon. Basin of the river

2012 ◽  
Author(s):  
Tatiana Novichkova ◽  
Keyword(s):  
Amazon Basin
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