Papers by Jennifer Hanselman
CLAM age model and pollen profile of sediment core Huinamarca
Data from: Modern pollen assemblages of the Neotropics
Aim: To provide a database of modern pollen abundances from a diversity of Neotropical locations.... more Aim: To provide a database of modern pollen abundances from a diversity of Neotropical locations. Location: The Neotropics, especially western Amazonia, the Andes, The Galápagos, Central America, Puerto Rico, and Mexico. Methods: Over a 30-year period, mud-water interface samples, moss polsters, soils, and pollen traps were used to assay modern pollen rain. Standard extraction methods were used and a minimum of 300 terrestrial pollen grains counted and identified per sample. Bioclimatic data were assigned to each location, and sexual traits and pollination syndromes are provided for some genera. A detrended correspondence analysis (DCA) shows the structuring of the data relative to mean annual temperatures (MAT), mean annual precipitation (MAP), and precipitation of the driest quarter (PDQ). Probability density functions of distances among samples are calculated within and between Holdridge Life Zones, based on sample DCA scores. Results: The modern pollen of 636 locations are docum...
Modern pollen assemblages of the Neotropics
Journal of Biogeography, 2020
AimModern pollen assemblages provide a means to calibrate fossil pollen data and to provide a tra... more AimModern pollen assemblages provide a means to calibrate fossil pollen data and to provide a translation from habitat and vegetation type to pollen representation. Here we provide a database of modern pollen abundances from a broad range of neotropical habitats and locations.LocationThe Neotropics, especially western Amazonia, the Andes, The Galápagos, Central America, Puerto Rico and Mexico.TaxonAngiosperms and GymnospermsMethodsOver a 30‐year period, mud–water interface samples, moss polsters, soils and pollen traps were used to assay modern pollen assemblages. Standard extraction methods were used, and a minimum of 300 terrestrial pollen grains were counted and identified in each sample. Bioclimatic data were assigned to each location, and sexual traits and pollination syndromes are provided for some genera. A detrended correspondence analysis (DCA) shows the structuring of the data relative to mean annual temperatures (MAT), mean annual precipitation (MAP) and precipitation of ...
Palaeogeography, Palaeoclimatology, Palaeoecology, 2008
Glacial-Interglacial changes in moisture balance and the impact on vegetation in the southern hem... more Glacial-Interglacial changes in moisture balance and the impact on vegetation in the southern hemisphere tropical Andes (Bolivia/Peru).
Journal of Vegetation Science, 2009
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Journal of Quaternary Science, 2005
Two long sediment records (cores LTO1‐2B and LT01‐3B) from Lake Titicaca, Bolivia/Peru, are compa... more Two long sediment records (cores LTO1‐2B and LT01‐3B) from Lake Titicaca, Bolivia/Peru, are compared with a previously analysed Holocene record from this lake (core NE98‐1PC). The Holocene records of LT01‐2B and NE98‐1PC are similar. There are striking differences, however, between the MIS 5e sections of the long cores and the Holocene records. In these records, temperature is probably the dominant parameter that determines the total fossil pollen concentration and is used to time the onset and termination of deglaciation. In contrast, the relative and absolute abundance of specific taxa (e.g. Polylepis/Acaena, Chenopodiaceae) are indicators of relative moisture availability. Although the Holocene contains a period of aridity between ca. 8000 cal. yr BP and 4300 cal. yr BP, it is a minor event compared with the more extreme aridity of MIS 5e. Core LT01‐3B showed similar trends during MIS 5e when compared to LT01‐2B, as did NE98‐1PC when comparing Holocene records. MIS 5e and the Hol...
How typical are the last 20,000 years of climatic and vegetation change in the tropical Andes?
A consensus of global circulation models highlights the southern tropical Andes as the biodiversi... more A consensus of global circulation models highlights the southern tropical Andes as the biodiversity hotspot most likely to experience biome shift in the next century. The pace of the ongoing change finds its nearest parallel in that of the Younger Dryas at high latitudes. However, in the tropical Andes of Peru and Bolivia we find that there was no such
Non-linear vegetation responses to climate change: A paleoecological perspective from Lake Titicaca
Non-linear vegetation responses to climate change: A paleoecological perspective from Lake Titica... more Non-linear vegetation responses to climate change: A paleoecological perspective from Lake Titicaca. ... from Lake Titicaca provides a detailed record of past climate change that includes ... between glacial foreland to a productive (relatively) interglacial Andean grassland/shrubland ...
Global Change Biology, 2010
A 370 000‐year paleoecological record from Lake Titicaca provides a detailed record of past clima... more A 370 000‐year paleoecological record from Lake Titicaca provides a detailed record of past climate change in which interglacial periods are seen to have some elements of commonality, but also some key differences. We advance a conceptual feedback model to account for the observed changes that includes previously ignored lake effects. Today Lake Titicaca serves to warm the local environment by about 4–5 °C and also to increase rainfall. We observe that as water levels in the lake are drawn down due to warm, dry, interglacial conditions, there is a possible regional cooling as the lake effect on local microclimates diminishes. Positive feedback mechanisms promote drying until much of the lake basin is reduced to salt marsh. Consequently, the usual concept of upslope migration of species with warming would not be applicable in the Altiplano. If, as projected, the next century brings warmer and drier conditions than those of today, a tipping point appears to exist within ca. 1–2 °C of ...
Climate of The Past, 2016
A new global synthesis and biomization of long (> 40 kyr) pollen-data records is presented and... more A new global synthesis and biomization of long (> 40 kyr) pollen-data records is presented and used with simulations from the HadCM3 and FAMOUS climate models and the BIOME4 vegetation model to analyse the dynamics of the global terrestrial biosphere and carbon storage over the last glacial–interglacial cycle. Simulated biome distributions using BIOME4 driven by HadCM3 and FAMOUS at the global scale over time generally agree well with those inferred from pollen data. Global average areas of grassland and dry shrubland, desert, and tundra biomes show large-scale increases during the Last Glacial Maximum, between ca. 64 and 74 ka BP and cool substages of Marine Isotope Stage 5, at the expense of the tropical forest, warm-temperate forest, and temperate forest biomes. These changes are reflected in BIOME4 simulations of global net primary productivity, showing good agreement between the two models. Such changes are likely to affect terrestrial carbon storage, which in turn influence...
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Papers by Jennifer Hanselman