Browsing by Subject "Amazon"

Now showing 1 - 4 of 4
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    Brazil’s Soy Moratorium: Current Expansion Capacities, Extension to the Cerrado, and Increasing Compliant Production
    (2017-08) Nepstad, Lucy
    Brazil’s Soy Moratorium has been credited with reducing deforestation rates in Amazonia, yet compliant land is finite and diminishing in response to rapidly increasing international demand for exports. Furthermore, whereas the Soy Moratorium has lessened the role of soy as a direct driver of Amazonian forest loss, it does not apply to the Cerrado, where recent soy expansion has come at the cost of ecologically valuable vegetation. Here we quantify the remaining potential for Soy Moratorium-compliant expansion at the microregion level in both the Amazon, where the current Soy Moratorium applies, and in the Cerrado, under a scenario where the Soy Moratorium is extended to the biome. We evaluate 189 microregions including all soy producing area in the Amazon and all area in the Cerrado. We determine potential compliant production increases for both regions using three approaches: expanding soy onto all Soy Moratorium-eligible land, closing yield gaps on current lands, and introducing integrated-crop-livestock systems with soy (ICLS) onto established pasture. We find 18.0 Mha of additional remaining eligible area in the Amazon and a hypothetical 67.9 Mha in the Cerrado, of which 81.0% and 62.3%, respectively, are estimated to be suitable for soy production. Utilizing all available land could over quintuple production from 2014 levels (466% increase), while restricting expansion to suitable land would result in a quadrupling of soy production (324% increase). However, any new soy expansion on eligible land would displace existing land uses, which may lead to leakage. Closing yield gaps on current lands could increase production only marginally (21.8% increase), while ICLS could generate meaningful production increases through areal expansion (37.5% increase) without facing leakage obstacles and while increasing financial benefits for farmers. Our findings suggest that adoption of a Cerrado Soy Moratorium would lead to a spatial shift in production away from rapidly transforming soy centers such as Matopiba and Central Mato Grosso, and into central and southwestern Cerrado where there is more concentrated eligible expansion area.
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    A new genus of long-horned caddisfly from the Amazon basin (Trichoptera: Leptoceridae: Grumichellini)
    (Magnolia Press, 2004) Holzenthal, Ralph W.; Pes, Ana Maria Oliveira
    Amazonatolica hamadae, new genus, new species (Leptoceridae: Grumichellini), is described from the Amazon basin of Brazil. The adult male and female, larva, pupa and case are described and illustrated. The biology and habitat of the new species is unusual for members of its tribe in that it occurs attached to vegetation in acidic, lowland streams.
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    Systematics Of Cernotina Ross And Cyrnellus Banks (Insecta: Trichoptera: Polycentropodidae)
    (2020-07) Camargos, Lucas
    The family Polycentropodidae occurs worldwide, and is represented in the Americas by Cernotina Ross 1938, Cyrnellus Banks 1913, Nyctiophylax Brauer 1865, Polycentropus Banks 1907 and Polyplectropus Ulmer 1905. Cernotina and Cyrnellus are exclusive to the New World, reaching their highest diversity in the Neotropics, with 75 and 12 described species respectively. Despite this diversity, none of the two have had revisionary work done, and the taxonomic information is scattered in many different papers by many authors across the 20th and early 21st Century. In Chapter 1, I ran the first phylogenetic analyses on the diverse genus Cernotina, using morphological characters of the male adult, especially the genitalia. To analyze the character matrix, I used Maximum Parsimony and Bayesian inference. In Maximum Parsimony, I used equally-weighted analyses with two different search strategies, one simple run and another with multiple rounds saving suboptimal trees to filter for a better set of most parsimonious trees, and an implied-weights analysis, using a posteriori character weigthing to achieve better resolution. In the Bayesian inference, I used Mk model + lognormal distribution, commonly used in morphological data. The results suggest the monophyly of Cernotina, adds phylogenetic evidence for synonymization of Ce. perpendicularis with Ce. lanceolata, and Ce. hastilis with Ce. nigridentata, and group certain species with morphological and geographic congruence, such as Ce. acalyptra + Ce. cystophora + Ce. encrypta, and Ce. lutea + Ce. cadeti, respectively. However, the overall resolution of the simple maximum-parsimony and the Bayesian trees were very low. In addition, the branch support for most nodes is also very low. This result might be due to the nature of the genitalic characters of Cernotina, being extremely variable on all its components, making the task of finding character congruence difficult. With additional data such as DNA sequence and geometric morphometrics, such issues could be alleviated. In Chapter 2, I revised the genus Cernotina at species-level. I discussed the complex homology of the morphological characters of the male genitalia, especially concerning the intermediate appendage and its relation to the Xth tergum and the preanal appendage, produced illustrations and comparative diagnoses for each species in the genus, and taxonomic descriptions for 64 species. In addition, I described 16 new species. I also proposed 2 synonymies considering the phylogenetic data from Chapter 1: Ce. lanceolata as junior synonym of Ce. perpendicularis, and Ce. nigridentata as junior synonym of Ce. hastilis. In Chapter 3, I revised the genus Cyrnellus at species-level. I also discussed the homology of the morphological characters of the much simpler male genitalia of the genus, produced a key to species of Cyrnellus, provided illustrations, and full taxonomic descriptions for 11 species. In addition, I reinstated the validity of Cy. minimus based on the morphology of the inferior appendage in ventral view. I also synonymized 2 species based on morphological similarity and high variability among specimens: Cy. keskes as junior synonym of Cy. minimus, and Cy. kozepes as junior synonym of Cy. ulmeri.
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    Understanding Tropical South American Rainfall Response to Global Climate Dynamics: A Speleothem Multi-Proxy Approach
    (2024-05) Parmenter, Dylan
    One of the greatest challenges facing climate scientists today is predicting large scale tropical rainfall response to climate change. One of the goals of speleothem paleoclimatology has been focused on using stalagmite oxygen isotopes to reconstruct tropical rainfall response to global climate processes on millennial and orbital timescales, in the hope that proxy enabled models may improve rainfall predictability. In South America, oxygen isotope records in the Andes and Amazon Basin have helped to paint a picture of large-scale rainfall response to glacial/interglacial cycles, greenhouse gasses, and ocean circulation. These studies interpret changes in oxygen isotope composition as reflecting rainout along a give moisture trajectory. While this type of analysis is informative in terms of inferring large-scale rainfall changes, complimentary proxies may help to constrain changes to specific regions, especially in cases where the moisture reaching a given site travels a long distance, or where the moisture source changed over time. In this dissertation, we have extended existing oxygen isotope records in the Eastern Amazon and Central Peruvian Andes deeper in time, with the new Amazon record pushing another 25,000 years into the Last Glacial, and the new Peru record extending another 55,000 years, now covering the entire Last Glacial Period and part of the Last Interglacial. In order to constrain rainfall to these specific regions, we analyzed Metal to Calcium ratios, which can be used as a proxy for local aridity, for both our extended portions of the records and for multiple intervals where only oxygen isotopes were published. We also replicated previously published oxygen isotope ratios with a new sample from the Central Peruvian Andes that grew over a precessional cycle during the Penultimate Glacial, and obtained Metal/Calcium ratios to test our hypotheses further in time. Our multi-proxy findings suggest that the Eastern Amazon oxygen isotope record does in fact reflect regional rainfall, and that high-latitude forcing is the primary control for Amazon rainfall variability during the Last Glacial on millennial timescales. In the Central Peruvian Andes, however, our record indicates that the majority of high-latitude forced millennial scale variability occurred further upstream. The lack of end-member shifts in our carbon isotope records from both regions suggests that vegetation did not undergo any major changes on millennial or orbital timescales over the last glacial/interglacial cycles. On orbital timescales, our records indicate that a rainfall dipole exists between the two regions, controlled by the regional Walker Circulation. During periods of higher orbital variability such as the Holocene, Last Interglacial, and Penultimate Glacial, our results suggest that this circulation pattern is controlled by regional insolation. Over the Last Glacial period when eccentricity was low, however, the pattern appears locked and does not respond to insolation, with sustained rainout in the Peruvian Andes, and higher subsidence causing overall drier conditions in the Eastern Amazon. Possible mechanisms causing this locked regional Walker Circulation include ice volume and greenhouse forcing, the latter of which also seems to have exerted a direct control on Eastern Amazon rainfall across Termination 1 and the MIS 4/3 boundary.