scholarly journals Analyzing a phenological anomaly in Yucca of the southwestern United States

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Laura Brenskelle ◽  
Vijay Barve ◽  
Lucas C. Majure ◽  
Rob P. Guralnick ◽  
Daijiang Li
Keyword(s):  
Biotic Interactions ◽  
Early Spring ◽  
Climate Variables ◽  
Yucca Schidigera ◽  
Temperature And Precipitation ◽  
Seasonal Factors ◽  
Yucca Brevifolia ◽  
Desert Southwest ◽  
Joshua Trees ◽  
Community Science

AbstractYucca in the American desert Southwest typically flowers in early spring, but a well-documented anomalous bloom event occurred during an unusually cold and wet late fall and early winter 2018–2019. We used community science photographs to generate flowering presence and absence data. We fit phenoclimatic models to determine which climate variables are explanatory for normal flowering, and then we tested if the same conditions that drive normal blooming also drove the anomalous blooming event. Flowering for Yucca brevifolia (Joshua tree) and Yucca schidigera (Mojave yucca) is driven by complex, nonlinear interactions between daylength, temperature, and precipitation. To our surprise, early-season flowering odds are highest in colder and drier conditions, especially for Joshua trees, but increase with precipitation late-season. However, the models used to fit normal blooming overpredicted the number of anomalous blooms compared to what was actually observed. Thus, predicting anomalous flowering events remains a challenge for quantitative phenological models. Because our model overpredicted the number of anomalous blooms, there are likely other factors, such as biotic interactions or other seasonal factors, which may be especially important in controlling what is presumed to be rare, out-of-season flowering in desert-adapted Yucca.

scholarly journals Predicting Phenological Anomaly: a Case Study of Yucca in the Southwestern United States

2021 ◽  
Author(s):  
Laura Brenskelle ◽  
Vijay Barve ◽  
Lucas Majure ◽  
Rob P. Guralnick ◽  
Daijiang Li
Keyword(s):  
Biotic Interactions ◽  
Early Spring ◽  
Nonlinear Interactions ◽  
Climate Variables ◽  
Early Winter ◽  
Temperature And Precipitation ◽  
Seasonal Factors ◽  
Desert Southwest ◽  
Joshua Trees

Abstract Yucca in the American desert Southwest typically flowers in early spring, but a well-documented anomalous bloom event occurred during an unusually cold and wet late fall and early winter 2018–2019. We used citizen science photographs as a means to generate flowering presence and absence data. We fit phenoclimatic models to determine which climate variables are explanatory for normal flowering, and then we tested if the same conditions that drive normal blooming also drove the anomalous blooming event. Flowering for Y. brevifolia and Y. schidigera is driven by complex, nonlinear interactions between daylength, temperature, and precipitation. To our surprise, early-season flowering odds are highest in colder and drier conditions, especially for Joshua trees, but increase with precipitation late-season. However, the models used to fit normal blooming overpredicted the number of anomalous blooms compared to what was actually observed. Thus, predicting anomalous flowering events remains a challenge for quantitative phenological models. Because our model overpredicted the number of anomalous blooms, there are likely other factors, such as biotic interactions or other seasonal factors, which may be especially important in controlling what is presumed to be rare, out-of-season flowering in desert-adapted Yucca.

scholarly journals Specimen-based analysis of morphology and the environment in ecologically dominant grasses: the power of the herbarium

2018 ◽  
Vol 374 (1763) ◽  
pp. 20170403 ◽  
Author(s):  
Christine A. McAllister ◽  
Michael R. McKain ◽  
Mao Li ◽  
Bess Bookout ◽  
Elizabeth A. Kellogg
Keyword(s):  
Morphological Characters ◽  
Automated Image Analysis ◽  
Climate Variables ◽  
Theme Issue ◽  
Analysis Techniques ◽  
Temperature And Precipitation ◽  
Sessile Spikelet ◽  
Effects Of Temperature ◽  
The Relationship ◽  
Image Analysis Techniques

Herbaria contain a cumulative sample of the world's flora, assembled by thousands of people over centuries. To capitalize on this resource, we conducted a specimen-based analysis of a major clade in the grass tribe Andropogoneae, including the dominant species of the world's grasslands in the genera Andropogon , Schizachyrium , Hyparrhenia and several others. We imaged 186 of the 250 named species of the clade, georeferenced the specimens and extracted climatic variables for each. Using semi- and fully automated image analysis techniques, we extracted spikelet morphological characters and correlated these with environmental variables. We generated chloroplast genome sequences to correct for phylogenetic covariance and here present a new phylogeny for 81 of the species. We confirm and extend earlier studies to show that Andropogon and Schizachyrium are not monophyletic. In addition, we find all morphological and ecological characters are homoplasious but variable among clades. For example, sessile spikelet length is positively correlated with awn length when all accessions are considered, but when separated by clade, the relationship is positive for three sub-clades and negative for three others. Climate variables showed no correlation with morphological variation in the spikelet pair; only very weak effects of temperature and precipitation were detected on macrohair density. This article is part of the theme issue ‘Biological collections for understanding biodiversity in the Anthropocene'.

scholarly journals Weed seed bank emergence across the Corn Belt

Weed Science ◽  
1997 ◽  
Vol 45 (1) ◽  
pp. 67-76 ◽  
Author(s):  
Frank Forcella ◽  
Robert G. Wilson ◽  
Jack Dekker ◽  
Robert J. Kremer ◽  
John Cardina ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Field Experiments ◽  
Soil Depth ◽  
Early Spring ◽  
Temperature And Precipitation ◽  
Secondary Dormancy ◽  
Giant Foxtail ◽  
Green Foxtail ◽  
Viable Seeds ◽  
Common Purslane

Field experiments, conducted from 1991 to 1994, generated information on weed seedbank emergence for 22 site-years from Ohio to Colorado and Minnesota to Missouri. Early spring seedbank densities were estimated through direct extraction of viable seeds from soil cores. Emerged seedlings were recorded periodically, as were daily values for air and soil temperature, and precipitation. Percentages of weed seedbanks that emerged as seedlings were calculated from seedbank and seedling data for each species, and relationships between seedbank emergence and microclimatic variables were sought. Fifteen species were found in 3 or more site-years. Average emergence percentages (and coefficients of variation) of these species were as follows: giant foxtail, 31.2 (84%); velvetleaf, 28.2 (66); kochia, 25.7 (79); Pennsylvania smartweed, 25.1 (65); common purslane, 15.4 (135); common ragweed, 15.0 (110); green foxtail, 8.5 (72); wild proso millet, 6.6 (104); hairy nightshade, 5.2 (62); common sunflower, 5.0 (26); yellow foxtail, 3.4 (67); pigweed species, 3.3 (103); common lambsquarters, 2.7 (111); wild buckwheat, 2.5 (63), and prostrate knotweed, 0.6 (79). Variation among site-years, for some species, could be attributed to microclimate variables thought to induce secondary dormancy in spring. For example, total seasonal emergence percentage of giant foxtail was related positively to the 1st date at which average daily soil temperature at 5 to 10 cm soil depth reached 16 C. Thus, if soil warmed before mid April, secondary dormancy was induced and few seedlings emerged, whereas many seedlings emerged if soil remained cool until June.

Effects of Environmental Stress on Primate Populations

2018 ◽  
Vol 47 (1) ◽  
pp. 417-434 ◽  
Author(s):  
Jason M. Kamilar ◽  
Lydia Beaudrot
Keyword(s):  
Environmental Stress ◽  
Life History Traits ◽  
Abiotic Factors ◽  
Scale Up ◽  
Biotic Interactions ◽  
Camera Traps ◽  
Ranging Behavior ◽  
Temperature And Precipitation ◽  
Macro Scale ◽  
Physiological Demands

Environmental stress on primate populations can take many forms. Abiotic factors, such as temperature and precipitation, may directly influence the behavior of primates owing to physiological demands of thermoregulation or through indirect influences on vegetation that primates rely on for food. These effects can also scale up to the macro scale, impacting primate distributions and evolution. Primates also encounter stress during interactions within and between species (i.e., biotic interactions). For example, selective pressure from male-perpetrated infanticide can drive the development of female counterstrategies and can impact life-history traits. Predation on primates can modify group size, ranging behavior, and habitat use. Finally, humans have influenced primate populations for millennia. More recently, hunting, habitat disturbance, disease, and climate change have increased in frequency and severity with detrimental impacts on primate populations worldwide. These effects and recent evidence from camera traps emphasize the importance of maintaining protected areas for conserving primate populations.

The Brain Damage Hypothesis of the Seasonality of Births in Schizophrenia and Major Affective Disorders: Evidence from Computerised Tomography

1992 ◽  
Vol 160 (3) ◽  
pp. 390-397 ◽  
Author(s):  
Emilio Sacchetti ◽  
Alessandro Calzeroni ◽  
Antonio Vita ◽  
Andrea Terzi ◽  
Franco Pollastro ◽  
...  
Keyword(s):  
Brain Damage ◽  
Affective Disorders ◽  
Early Spring ◽  
Early Summer ◽  
Cortical Atrophy ◽  
Primary Role ◽  
Seasonal Factors ◽  
History Of ◽  
The Brain

Although the excess of schizophrenic births in the winter and early spring has been replicated and some non-conclusive work supports the same seasonal birth trend in patients with major affective disorders, the aetiopathogenetic foundations of this phenomenon remain uncertain. The primary role of perinatal seasonal factors that predispose to the development of schizophrenia via induction of brain damage has been invoked, as has a tendency for patients to conceive during the spring and early summer. In order to test these two hypotheses, cerebral ventricular size and cortical atrophy in 206 schizophrenics and 107 patients with major affective disorders were assessed by CT and analysed in relation to month of birth. Compared with schizophrenics born during the remainder of the year, those born between December and April, particularly in cases lacking a family history of schizophrenia, showed increased chances for ventricular enlargement, but not for cortical atrophy. No association between season of birth and central or cortical atrophy was found for patients with major affective disorders. This suggests that the brain-damaging effect played by perinatal seasonal factors has both a disease and an anatomical specificity.

scholarly journals Determining the sensitivity of grassland area burned to climate variation in Xilingol, China, with an autoregressive distributed lag approach

2019 ◽  
Vol 28 (8) ◽  
pp. 628 ◽  
Author(s):  
Ali Hassan Shabbir ◽  
Jiquan Zhang ◽  
Xingpeng Liu ◽  
James A. Lutz ◽  
Carlos Valencia ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wildland Fire ◽  
Strong Relationship ◽  
Maximum Temperature ◽  
Climate Variables ◽  
Area Burned ◽  
Distributed Lag ◽  
Temperature And Precipitation ◽  
Autoregressive Distributed Lag ◽  
The Relationship

We examined the relationship between climate variables and grassland area burned in Xilingol, China, from 2001 to 2014 using an autoregressive distributed lag (ARDL) model, and describe the application of this econometric method to studies of climate influences on wildland fire. We show that there is a stationary linear combination of non-stationary climate time series (cointegration) that can be used to reliably estimate the influence of different climate signals on area burned. Our model shows a strong relationship between maximum temperature and grassland area burned. Mean monthly wind speed and monthly hours of sunlight were also strongly associated with area burned, whereas minimum temperature and precipitation were not. Some climate variables like wind speed had significant immediate effects on area burned, the strength of which varied over the 2001–14 observation period (in econometrics terms, a ‘short-run’ effect). The relationship between temperature and area burned exhibited a steady-state or ‘long-run’ relationship. We analysed three different periods (2001–05, 2006–10 and 2011–14) to illustrate how the effects of climate on area burned vary over time. These results should be helpful in estimating the potential impact of changing climate on the eastern Eurasian Steppe.

Do local perceptions of climate variability and changes correspond to observed climate changes? – a comparative study from Nepal as one of the most climate vulnerable countries

2021 ◽  
Keyword(s):  
Climate Change ◽  
Climate Changes ◽  
Climate Variables ◽  
Focus Group Discussions ◽  
Group Discussions ◽  
Local Perceptions ◽  
Temperature And Precipitation ◽  
Local Residents ◽  
Perceived Temperature ◽  
People’S Perceptions

Abstract This study explored people’s perceptions of climate change by conducting interviews and focus group discussions with local residents of three ecological regions of Nepal, i.e., Mountain, Mid-hills and Low-land. Climatic measurements from meteorological stations of the regions were acquired for the period of 1988 to 2018. We compared the people’s perception with trends and variabilities of observed temperature and rainfall patterns. The results showed that over the last three decades, temperature and precipitation trends, and variability between regions varied largely corroborating with the local experiences. The temperature increased in Mountain, Mid-hills, and Low-land by 0.061° C yr−1, 0.063° C yr−1 and 0.017° C yr−1 respectively. On the contrary, rainfall reduced by −9.7 mm yr−1, −3.6 mm yr−1, and −0.04 mm yr−1 for the regions respectively. While the amount of rainfall decrease observed in the Mountain was highest, its variability was found relatively low; and vice-versa in Low-land. Approximately 88% interviewees perceived temperature rise, and 74% noticed rainfall decline. Local residents linked these changes with their livelihood activities and exemplified with, for example, crop’s quality and quantity; and birds’ migration. The results indicate that local understandings complement the scarce observational data and provides a reliable and additional foundations to determine changes in climatic variables. Moreover, the result infers that the small changes in climate variables have noticeable implications on human behavior change. Therefore, besides active participation of local communities, integrating local understanding is crucial in developing climate change related policies and strategies at local and national levels.

Plankton succession and assemblage structure in two neighbouring littoral ecosystems in the north-west Mediterranean Sea

2005 ◽  
Vol 56 (1) ◽  
pp. 69 ◽  
Author(s):  
J.-L. Jamet ◽  
N. Jean ◽  
G. Bogé ◽  
S. Richard ◽  
D. Jamet
Keyword(s):  
Mediterranean Sea ◽  
Physical Environment ◽  
Human Activities ◽  
Early Spring ◽  
North West ◽  
Classical Scheme ◽  
The North ◽  
Seasonal Factors ◽  
Northern Winter ◽  
Plankton Communities

We studied seasonal variations in bacterial abundance and succession in phyto- and zooplankton assemblages (particularly small taxa) in two neighbouring shallow bays (near Toulon, Mediterranean Sea, France): Little Bay (polluted, eutrophic), and Niel Bay (less polluted, oligotrophic). In Little Bay, bacteria developed in northern spring and phytoplankton (Dinophyceae > 20 µm) in late northern winter–early spring. Zooplankton levels peaked at the end of northern spring and in autumn; this community was dominated by Oithona nana. In Niel Bay, bacterial levels peaked during northern spring and autumn. Phytoplankton (Dinophyceae, Bacillariophyceae) abundance was low and only peaked in June. Zooplankton levels peaked in northern mid-summer. Little Bay was influenced more by the land and by human activities than by the sea. Seasonal factors (e.g. water temperature) and sudden influences (e.g. rain and, indirectly, Mistral wind) may have modified the succession of the plankton communities in this bay. Successions did not follow Margalef’s model and the classical scheme for zooplankton. Conversely, Niel Bay functioning and plankton assemblages were most influenced by the physical environment of the sea than by the land or by human activities. Successions were closely related to the classical scheme of the Mediterranean Sea.

scholarly journals Decadal changes in glacier parameters in the Cordillera Blanca, Peru, derived from remote sensing

2008 ◽  
Vol 54 (186) ◽  
pp. 499-510 ◽  
Author(s):  
Adina E. Racoviteanu ◽  
Yves Arnaud ◽  
Mark W. Williams ◽  
Julio Ordoñez
Keyword(s):  
Glacier Area ◽  
Climate Variables ◽  
Upward Trend ◽  
Cordillera Blanca ◽  
Temperature And Precipitation ◽  
Glacier Terminus ◽  
Global Land ◽  
Western Side ◽  
Average Rise ◽  
The Tropics

AbstractWe present spatial patterns of glacier fluctuations from the Cordillera Blanca, Peru, (glacier area, terminus elevations, median elevations and hypsography) at decadal timescales derived from 1970 aerial photography, 2003 SPOT5 satellite data, Geographic Information Systems (GIS) and statistical analyses. We derived new glacier outlines from the 2003 SPOT images, and ingested them in the Global Land and Ice Measurements from Space (GLIMS) glacier database. We examined changes in glacier area on the eastern and western side of the Cordillera in relation to topographic and climate variables (temperature and precipitation). Results include (1) an estimated glacierized area of 569.6 ± 21 km2 in 2003, (2) an overall loss in glacierized area of 22.4% from 1970 to 2003, (3) an average rise in glacier terminus elevations by 113 m and an average rise in the median elevation of glaciers by 66 m, showing a shift of ice to higher elevations, especially on the eastern side of the Cordillera, and (4) an increase in the number of glaciers, which indicates disintegration of ice bodies. Annual air temperature showed a significant upward trend in the last 30 years, with larger temperature increases at lower elevations. There was a slight but not significant decrease in precipitation. Our results are consistent with glacier retreat and warming trends noted in the last three decades in the tropics.

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