Taphonomic Signatures On Modern Caribbean Bivalve Shells As Indicators Of Environmental Conditions (Belize, Central America)

AbstractLarge mammal herbivores are important drivers of plant evolution and vegetation patterns, but the extent to which plant trait and ecosystem geography currently reflect the historical distribution of extinct megafauna is unknown. We address this question for South and Central America (Neotropical biogeographic realm) by compiling data on plant defence traits, climate, soil, and fire, as well as on the historical distribution of extinct megafauna and extant mammal herbivores. We show that historical mammal herbivory, especially by extinct megafauna, and soil fertility explain substantial variability in wood density, leaf size, spines and latex. We also identified three distinct regions (‘‘antiherbiomes’’), differing in plant defences, environmental conditions, and megafauna history. These patterns largely matched those observed in African ecosystems, where abundant megafauna still roams, and suggest that some ecoregions experienced savanna-to-forest shifts following megafauna extinctions. Here, we show that extinct megafauna left a significant imprint on current ecosystem biogeography.

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Phylogeography and morphometric variation in the Cinnamon Hummingbird complex: Amazilia rutila (Aves: Trochilidae)

Avian Research ◽

10.1186/s40657-021-00295-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Melisa Vázquez-López ◽

Nandadevi Córtes-Rodríguez ◽

Sahid M. Robles-Bello ◽

Alfredo Bueno-Hernández ◽

Luz E. Zamudio-Beltrán ◽

...

Keyword(s):

Central America ◽

Environmental Conditions ◽

Pacific Coast ◽

Yucatan Peninsula ◽

Southern Mexico ◽

Morphometric Variation ◽

Divergence Time Estimates ◽

Yucatán Peninsula ◽

The Pacific ◽

Over Time

Abstract Background The Mesoamerican dominion is a biogeographic area of great interest due to its complex topography and distinctive climatic history. This area has a large diversity of habitats, including tropical deciduous forests, which house a large number of endemic species. Here, we assess phylogeographic pattern, genetic and morphometric variation in the Cinnamon Hummingbird complex Amazilia rutila, which prefers habitats in this region. This resident species is distributed along the Pacific coast from Sinaloa—including the Tres Marías Islands in Mexico to Costa Rica, and from the coastal plain of the Yucatán Peninsula of Mexico south to Belize. Methods We obtained genetic data from 85 samples of A. rutila, using 4 different molecular markers (mtDNA: ND2, COI; nDNA: ODC, MUSK) on which we performed analyses of population structure (median-joining network, STRUCTURE, FST, AMOVA), Bayesian and Maximum Likelihood phylogenetic analyses, and divergence time estimates. In order to evaluate the historic suitability of environmental conditions, we constructed projection models using past scenarios (Pleistocene periods), and conducted Bayesian Skyline Plots (BSP) to visualize changes in population sizes over time. To analyze morphometric variation, we took measurements of 5 morphological traits from 210 study skins. We tested for differences between sexes, differences among geographic groups (defined based on genetic results), and used PCA to examine the variation in multivariate space. Results Using mtDNA, we recovered four main geographic groups: the Pacific coast, the Tres Marías Islands, the Chiapas region, and the Yucatán Peninsula together with Central America. These same groups were recovered by the phylogenetic results based on the multilocus dataset. Demography based on BSP results showed constant population size over time throughout the A. rutila complex and within each geographic group. Ecological niche model projections onto past scenarios revealed no drastic changes in suitable conditions, but revealed some possible refuges. Morphometric results showed minor sexual dimorphism in this species and statistically significant differences between geographic groups. The Tres Marías Islands population was the most differentiated, having larger body size than the remaining groups. Conclusions The best supported evolutionary hypothesis of diversification within this group corresponds to geographic isolation (limited gene flow), differences in current environmental conditions, and historical habitat fragmentation promoted by past events (Pleistocene refugia). Four well-defined clades comprise the A. rutila complex, and we assess the importance of a taxonomic reevaluation. Our data suggest that both of A. r. graysoni (Tres Marías Islands) and A. r. rutila (Pacific coast) should be considered full species. The other two strongly supported clades are: (a) the Chiapas group (southern Mexico), and (b) the populations from Yucatán Peninsula and Central America. These clades belong to the corallirostris taxon, which needs to be split and properly named.

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Hot bats go cold: heterothermy in neotropical bats

Canadian Journal of Zoology ◽

10.1139/cjz-2016-0318 ◽

2017 ◽

Vol 95 (12) ◽

pp. 909-912 ◽

Cited By ~ 2

Author(s):

Zenon J. Czenze ◽

Miranda B. Dunbar

Keyword(s):

Body Temperature ◽

Central America ◽

Tropical Forests ◽

Rectal Temperature ◽

Environmental Conditions ◽

Tropical Africa ◽

Acclimation Period ◽

Neotropical Bats ◽

Energy Saving Technique ◽

Shed Light

Torpor is common in bats, but has historically been viewed as an energy-saving technique reserved for temperate and subarctic climates; however, torpor use is common across several tropical bat families. Central America hosts a great diversity of bats with approximately 150 species, yet data from this area are lacking compared with tropical Africa and Australia. We investigated thermoregulatory responses of bats from neotropical Belize and captured adult bats in the tropical forests of Lamanai Archeological Reserve, Belize. After a 12 h acclimation period, we recorded rectal temperature prior to and after exposing bats to an ambient temperature (Ta) of 7 °C for up to 2 h in an environmental chamber. All 11 species across four families expressed torpor to some degree upon exposure to cool temperatures. Individuals from Vespertilionidae defended the lowest resting body temperature (Tb) and showed the greatest decrease in Tb after acute exposure to low Ta. Our data help to establish a new spectrum of physiological ability for this group of mammals and shed light on the evolution of torpor and heterothermy. We show that energy conservation is important even in warm and energetically stable environmental conditions. Understanding how and why torpor is used in warm climates will help to better define paradigms in physiological ecology.

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Nixtamal techniques for different maize races prepared as tortillas and tostadas by women of Chiapas, Mexico

Journal of Ethnic Foods ◽

10.1186/s42779-022-00116-9 ◽

2022 ◽

Vol 9 (1) ◽

Author(s):

Gabriela Palacios-Pola ◽

Hugo Perales ◽

Erin I. J. Estrada Lugo ◽

Juan de Dios Figueroa-Cárdenas

Keyword(s):

Central America ◽

Environmental Conditions ◽

Cooking Time ◽

Grain Composition ◽

High Quality ◽

Alkaline Water ◽

Relevant Variables ◽

Maize Type ◽

Special Process ◽

Maize Race

AbstractNixtamalization, which means cooking maize in alkaline water, is the central technique for the culinary use of maize in Mexico and Central America. Without this procedure, relying on maize as the basic starch staple is inadequate because of nutriment deficiencies. Mexico has more than 50 principal racial types of maize, and these differ in grain qualities that can require the adjustment of the nixtamalization process. Properties such as hardness and grain composition influence nixtamalization because they are related to the absorption of water that occurs during cooking and steeping. Some maize preparations, like tortillas and tostadas, can also require the adjustment of nixtamalization to obtain a high-quality foodstuff. We studied how women in three regions of the state of Chiapas, which differ in the prevalent maize race available, prepare their nixtamal and whether they make changes according to the type of food they prepare. Interviews of 30 women follow the measure of relevant variables when the women prepared nixtamal. We found that nixtamalization is adjusted for different grain hardnesses and for environmental conditions. Variations were found in the cooking time of the nixtamal, in the amount of time the nixtamal was steeped, and in a special process of double boiling of the nixtamal performed by some women for tostadas. Women that specialize in production for the market have developed variations preferred by consumers. As practiced by women in Chiapas, nixtamalization is a flexible technique that is adjusted for maize type and for food preparations.

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Canavalia ensiformis (jack bean).

10.1079/isc.14486.20203482789 ◽

2020 ◽

Author(s):

Eduardo A. Ventosa Febles

Keyword(s):

Central America ◽

Invasive Plants ◽

Environmental Conditions ◽

Cover Crop ◽

Green Manure ◽

Jack Bean ◽

Canavalia Ensiformis ◽

Disturbed Areas ◽

The Tropics

Abstract Canavalia ensiformis is a vine native to South and Central America that has been introduced in the tropics and subtropics worldwide. It is grown for food, fodder and as a cover crop or green manure. It can grow on depleted soils under harsh environmental conditions and become established in disturbed areas. It is listed in a database of invasive plants in Taiwan and has been identified as a transformer species with the potential to become invasive in Cuba.

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Recovery Plan for Tar Spot of Corn, Caused by Phyllachora maydis

Plant Health Progress ◽

10.1094/php-04-21-0074-rp ◽

2021 ◽

Author(s):

Camila Rocco da Silva ◽

Jill Check ◽

Joshua S MacCready ◽

Amos E Alakonya ◽

Robert L Beiriger ◽

...

Keyword(s):

South America ◽

Central America ◽

Environmental Conditions ◽

Fungal Pathogens ◽

Yield Losses ◽

Tar Spot ◽

America South ◽

The Caribbean ◽

First Time ◽

The U.S

Tar spot is a foliar disease of corn threatening production across the Americas. The disease was first documented in Mexico in 1904 and is now present in 15 additional countries throughout Central America, South America, and the Caribbean. Researchers and growers in Central America, South America, and the Caribbean consider tar spot to be a disease complex caused by multiple fungal pathogens. When environmental conditions are conducive for infection, these regions have experienced yield losses can reach up to 100%. In 2015, tar spot was detected in the U.S. for the first time in Illinois and Indiana. Since that time tar spot has spread across the U.S. corn-growing region, and the disease has been found in Florida, Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio, Pennsylvania, and Wisconsin. In 2020, tar spot was also found in southwest Ontario, Canada. Losses in the U.S. due to tar spot totaled an estimated 241 million bushels from 2018 to 2020. With the potential to continue to spread across the U.S. corn-growing states, much greater losses could result when environmental conditions are conducive.

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Environmental Conditions, and Phenolic Compounds Potential in the Leaves of Vitis Tiliifolia

10.21203/rs.3.rs-183717/v1 ◽

2021 ◽

Author(s):

Humberto Mata.Alejandro ◽

María Elena Galindo-Tovar ◽

Otto Leyva-Ovalle ◽

Franco Famiani ◽

Juan G Cruz-Castillo

Keyword(s):

Organic Matter ◽

Phenolic Compounds ◽

Central America ◽

Environmental Conditions ◽

Phenolic Content ◽

The State ◽

Caribbean Region ◽

Maximum Entropy Modeling ◽

The Caribbean ◽

Potential Area

Abstract The wild vine Vitis tiliifolia is found in Mexico, Central América, and the Caribbean region. In the Veracruz State, in Mexico, grows in several municipalities and is used for nutritional and therapeutic purposes. The geographical distribution and environment where this Vitis grow has not been recorded. The leaves of V. tiliifolia are rich in phenolic compounds but potential areas with vines of high phenolic compounds are unknown. An agroecological zoning model to identify potential areas for the cultivation and development of this species was performed. Potential areas having wild vines of high phenolic compounds in the leaves were also determined. The model included 95 vine georeferences, obtained from four municipalities of central Veracruz. These were analyzed with maximum entropy modeling, mapped with ArcMap software, and correlated with the phenolic compounds found in leaves collected in the georeferenced areas. A zoning map was produced, with a potential area of 2763.72 km2, which included the states of San Luis Potosi, Hidalgo, Veracruz, Puebla, Oaxaca, and Chiapas. Agroclimatic variables of seasonality of temperature, precipitation, and organic matter in the soil were the most important for the development of this species. In the state of Veracruz, vines with the potential of high phenolic content were found in 29 municipalities with characteristics suitable for its cultivation. The highest phenolic content potential was found at altitudes between 1000 and 2000 meters in the municipalities of Huatusco and Cosautlán in the State of Veracruz.

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Vibration Isolator System for Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017966x ◽

1990 ◽

Vol 48 (1) ◽

pp. 182-183

Author(s):

K. Ohi ◽

M. Mizuno ◽

T. Kasai ◽

Y. Ohkura ◽

K. Mizuno ◽

...

Keyword(s):

Electron Microscope ◽

Magnetic Fields ◽

Environmental Conditions ◽

Vibration Isolator ◽

Air Conditioners ◽

Vibration Isolators ◽

Large Size ◽

Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

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