Inter-specific transpiration differences between aspen, spruce, and pine in a sky-island ecosystem of the North American Great Basin

2021 ◽  
Vol 491 ◽  
pp. 119157
Author(s):  
Xinsheng Liu ◽  
Franco Biondi
Keyword(s):  
Great Basin ◽  
North American ◽  
The North ◽  
Island Ecosystem ◽  
Sky Island

North American rainfall patterns during past warm states: A proxy network-model comparison for the Last Interglacial and the mid-Holocene

2021 ◽  
Author(s):  
Cameron de Wet ◽  
Jessica Oster ◽  
Daniel Ibarra ◽  
Bryce Belanger
Keyword(s):  
North America ◽  
Pacific Northwest ◽  
Great Basin ◽  
North American ◽  
Last Interglacial ◽  
The North ◽  
Driving Mechanisms ◽  
Statistical Measures ◽  
Spatial Coverage ◽  
Rainfall Patterns

<p>The Last Interglacial (LIG) period (~129,000–116,000 years BP) and the mid-Holocene (MH) (~6,000 years BP) are the two most recent intervals with temperatures comparable to low emissions scenarios for the end of the 21<sup>st</sup> century. During the LIG and the MH differences in the seasonal and latitudinal distribution of insolation led to enhanced northern hemisphere high-latitude warmth relative to the pre-industrial, despite similar greenhouse gas concentrations, marking these intervals as potentially useful analogs for future change in regions like North America. Further, the inclusion of both LIG (127 ka) and MH (6 ka) experiments in the CMIP6-PMIP4 effort provides an opportunity to better understand the regional hydroclimate responses to radiative forcing during these two intervals. The dense coverage of paleoclimate proxy records for North America during the MH (N=260 sites) reveals a pattern of relative aridity in the Pacific Northwest and Western Canada and wetness in the southern Great Basin and Mexico. However, the seasonality and driving mechanisms of rainfall patterns across the continent remain poorly understood. Our understanding of terrestrial hydroclimate in North America during the LIG is more limited (N=39 sites), largely because the LIG is beyond the range of radiocarbon dating.</p><p>Here we present spatial comparisons between output from 14 PMIP4 global circulation models and LIG and MH networks of moisture-sensitive proxies compiled for the North American continent. We utilize two statistical measures of agreement – weighted Cohen’s Kappa and Gwet’s AC2 – to assess the degree of categorical agreement between moisture patterns produced by the models and the proxy networks for each time-slice. PMIP4 models produce variable precipitation anomalies relative to the pre-industrial for both the LIG and MH experiments, often disagreeing on both the sign and magnitude of precipitation changes across much of North America. The models showing the best agreement with the proxy network are similar but not identical for the two measures, with Gwet’s AC2 values tending to be larger than Cohen’s Kappa values for all models. This pattern is enhanced for the much larger MH proxy network and is likely related to the fact that Gwet’s AC2 is a more predictable statistic in the presence of high agreement. Overall agreement is lower for the mid-Holocene than for the LIG, reflecting smaller MH rainfall anomalies in the models. The models with the highest agreement scores during the LIG produce aridity in the Rocky Mountains and Pacific Northwest and wetness in Alaska, the Yukon, the Great Basin, and parts of the Mid-West and Eastern US, although spatial coverage of the proxies in these latter two regions is poor. The models with the highest agreement score for the mid-Holocene tend to produce aridity across Canada and the northern US with dry conditions extending down the US Pacific coast and increased wetness in the American Southeast and across the North American Monsoon region. Our analyses help elucidate the driving mechanisms of rainfall patterns during past warm states and can inform which models may be the most useful for predictions of near-future hydroclimate change across North America.</p>

scholarly journals Post-Wildfire Regeneration in a Sky-Island Mixed- Conifer Ecosystem of the North American Great Basin

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 900
Author(s):  
Mackenzie Kilpatrick ◽  
Franco Biondi
Keyword(s):  
Great Basin ◽  
Basal Area ◽  
Climatic Conditions ◽  
Ecosystem Responses ◽  
Engelmann Spruce ◽  
The North ◽  
Bristlecone Pine ◽  
Snake Range ◽  
Disturbance Processes ◽  
Sky Island

Information on wildfire impacts and ecosystem responses is relatively sparse in the Great Basin of North America, where subalpine ecosystems are generally dominated by five-needle pines. We analyzed existing vegetation, with an emphasis on regeneration following the year 2000 Phillips Ranch Fire, at a sky-island site in the Snake Range of eastern Nevada. Our main objective was to compare bristlecone pine (Pinus longaeva; PILO) post-fire establishment and survival to that of the co-occurring dominant conifers limber pine (Pinus flexilis; PIFL) and Engelmann spruce (Picea engelmannii; PIEN) in connection with site characteristics. Field data were collected in 40 circular 0.1 ha plots (17.8 m radius) randomly located using GIS so that half of them were inside (“burned”) and half were outside (“unburned”) the 2000 fire boundary. While evidence of previous burns was also found, we focused on impacts from the Phillips Ranch Fire. Mean total basal area, including live and dead stems, was not significantly different between plots inside the burn and plots outside the fire perimeter, but the live basal area was significantly less in the former than in the latter. Wildfire impacts did not limit regeneration, and indeed bristlecone seedlings and saplings were more abundant in plots inside the 2000 fire perimeter than in those outside of it. PILO regeneration, especially saplings, was more abundant than PIFL and PCEN combined, indicating that PILO can competitively regenerate under modern climatic conditions. Surviving PILO regeneration in burned plots was also taller than that of PIFL. By contrast, PCEN was nearly absent in the plots that had been impacted by fire. Additional research should explicitly address how climatic changes and disturbance processes may interact in shaping future vegetation dynamics.

Broad-scale impacts of an invasive native predator on a sensitive native prey species within the shifting avian community of the North American Great Basin

2020 ◽  
Vol 243 ◽  
pp. 108409 ◽  
Author(s):  
Peter S. Coates ◽  
Shawn T. O'Neil ◽  
Brianne E. Brussee ◽  
Mark A. Ricca ◽  
Pat J. Jackson ◽  
...  
Keyword(s):  
Great Basin ◽  
North American ◽  
Prey Species ◽  
Avian Community ◽  
The North ◽  
Broad Scale ◽  
Native Predator

Mass Harvesting, Ichthyofaunal Assemblages, and Ancestral Paiute Fishing in the North American Great Basin

2020 ◽  
Vol 85 (4) ◽  
pp. 715-736
Author(s):  
B. Sunday Eiselt
Keyword(s):  
Great Basin ◽  
North American ◽  
Fish Assemblages ◽  
Experimental Studies ◽  
Investment Model ◽  
Technology Investment ◽  
The North ◽  
Middle Range ◽  
Mean Size ◽  
Tui Chub

Documenting variability in the archaeological record is critical to our understanding human fishing adaptations in the North American Great Basin over time. Unfortunately, in the absence of robust middle range techniques for interpreting fishbone assemblages, many studies have been limited in their capacity to engage in theoretical discussions of the role of fishing in forager subsistence regimes. The Northern Paiute in Oregon and Nevada exploited seasonally aggregated tui chub (Siphateles bicolor) through mass-harvesting techniques using nets and baskets. This article integrates experimental studies with ethnographic and archaeological data to infer the types of fishing gear that were used from the reconstructed sizes of tui chub remains. The mean size of fish assemblages is compared to the coefficient of variation to identify fishing techniques based on the size parameters of gear types, and a technology investment model is used to assess regional variations in commitments to fishing in open lake and marshland settings. Results are compared to tui chub assemblages from two protohistoric archaeological sites in eastern Oregon, revealing two distinctive fishing strategies with general implications for the organization of labor by hunter-gatherer fisherfolk.

Geochronology and paleoenvironment of pluvial Harper Lake, Mojave Desert, California, USA

2014 ◽  
Vol 81 (2) ◽  
pp. 305-317 ◽  
Author(s):  
Anna L. Garcia ◽  
Jeffrey R. Knott ◽  
Shannon A. Mahan ◽  
Jordon Bright
Keyword(s):  
Great Basin ◽  
North American ◽  
Mojave Desert ◽  
Optically Stimulated Luminescence ◽  
Luminescence Dating ◽  
Jet Stream ◽  
Geologic Mapping ◽  
The North ◽  
Optically Stimulated Luminescence Dating ◽  
Marine Climate

AbstractAccurate reconstruction of the paleo-Mojave River and pluvial lake (Harper, Manix, Cronese, and Mojave) system of southern California is critical to understanding paleoclimate and the North American polar jet stream position over the last 500 ka. Previous studies inferred a polar jet stream south of 35°N at 18 ka and at ~ 40°N at 17–14 ka. Highstand sediments of Harper Lake, the upstream-most pluvial lake along the Mojave River, have yielded uncalibrated radiocarbon ages ranging from 24,000 to > 30,000 14C yr BP. Based on geologic mapping, radiocarbon and optically stimulated luminescence dating, we infer a ~ 45–40 ka age for the Harper Lake highstand sediments. Combining the Harper Lake highstand with other Great Basin pluvial lake/spring and marine climate records, we infer that the North American polar jet stream was south of 35°N about 45–40 ka, but shifted to 40°N by ~ 35 ka. Ostracodes (Limnocythere ceriotuberosa) from Harper Lake highstand sediments are consistent with an alkaline lake environment that received seasonal inflow from the Mojave River, thus confirming the lake was fed by the Mojave River. The ~ 45–40 ka highstand at Harper Lake coincides with a shallowing interval at downstream Lake Manix.

The North American Great Basin: A Sensitive Indicator of Climatic Change

1990 ◽  
pp. 323-359 ◽  
Author(s):  
Robert A. Wharton ◽  
Peter E. Wigand ◽  
Martin R. Rose ◽  
Richard L. Reinhardt ◽  
David A. Mouat ◽  
...  
Keyword(s):  
Climatic Change ◽  
Great Basin ◽  
North American ◽  
Sensitive Indicator ◽  
The North
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