When are leaves good thermometers? A new case for Leaf Margin Analysis

Paleobiology ◽  
1997 ◽  
Vol 23 (3) ◽  
pp. 373-390 ◽  
Author(s):  
Peter Wilf
Keyword(s):  
Species Richness ◽  
Multivariate Data ◽  
Species Abundance ◽  
Western Hemisphere ◽  
Mean Annual Temperature ◽  
Leaf Margin ◽  
Data Set ◽  
Leaf Analysis ◽  
Climate Analysis ◽  
Margin Analysis

Precise estimates of past temperatures are critical for understanding the evolution of organisms and the physical biosphere, and data from continental areas are an indispensable complement to the marine record of stable isotopes. Climate is considered to be a primary selective force on leaf morphology, and two widely used methods exist for estimating past mean annual temperatures from assemblages of fossil leaves. The first approach, Leaf Margin Analysis, is univariate, based on the positive correlation in modern forests between mean annual temperature and the proportion of species in a flora with untoothed leaf margins. The second approach, known as the Climate-Leaf Analysis Multivariate Program, is based on a modern data set that is multivariate. I argue here that the simpler, univariate approach will give paleotemperature estimates at least as precise as the multivariate method because (1) the temperature signal in the multivariate data set is dominated by the leaf-margin character; (2) the additional characters add minimal statistical precision and in practical use do not appear to improve the quality of the estimate; (3) the predictor samples in the univariate data set contain at least twice as many species as those in the multivariate data set; and (4) the presence of numerous sites in the multivariate data set that are both dry and extremely cold depresses temperature estimates for moist and nonfrigid paleofloras by about 2°C, unless the dry and cold sites are excluded from the predictor set.New data from Western Hemisphere forests are used to test the univariate and multivariate methods and to compare observed vs. predicted error distributions for temperature estimates as a function of species richness. Leaf Margin Analysis provides excellent estimates of mean annual temperature for nine floral samples. Estimated temperatures given by 16 floral subsamples are very close both to actual temperatures and to the estimates from the samples. Temperature estimates based on the multivariate data set for four of the subsamples were generally less accurate than the estimates from Leaf Margin Analysis. Leaf-margin data from 45 transect collections demonstrate that sampling of low-diversity floras at extremely local scales can result in biased leaf-margin percentages because species abundance patterns are uneven. For climate analysis, both modern and fossil floras should be sampled over an area sufficient to minimize this bias and to maximize recovered species richness within a given climate.

THE PALEOBOTANY AND PALEOECOLOGY OF THE EOCENE HERREN BEDS OF NORTH-CENTRAL OREGON, USA

Palaios ◽  
2019 ◽  
Vol 34 (9) ◽  
pp. 424-436 ◽  
Author(s):  
ANTHONY P. JIJINA ◽  
ELLEN D. CURRANO ◽  
KURT CONSTENIUS
Keyword(s):  
Pacific Northwest ◽  
Middle Eocene ◽  
Plant Macrofossils ◽  
Mean Annual Precipitation ◽  
Future Research ◽  
Mean Annual Temperature ◽  
Leaf Margin ◽  
North Central ◽  
The Pacific ◽  
Margin Analysis

ABSTRACT New collections of plant macrofossils and radiometric dates from the Herren beds of north-central Oregon provide the opportunity to document floral communities and calculate foliar-derived climate estimates from the warm early Eocene and the cooler middle Eocene. Plant macrofossils were collected from one fluvial site at East Birch Creek approximately 2 m below a 51.9 ± 0.9 Ma tuff. Collections were also made at two co-occurring fluvial sites at Arbuckle Mountain, whose ages are constrained to ca. 44.5–43.8 Ma based on a dated tuff from Willow Creek (44.5 ± 0.8 Ma) and reported ages for the overlying Clarno Formation. Floral findings show an almost complete vegetation overturn, with only two genera (Glyptostrobus and Allantodiopsis) appearing in both floras. Both floras are species poor, but the older East Birch Creek flora has higher richness and evenness than the younger Arbuckle Mountain flora. The four named genera at East Birch Creek are taxa found throughout Eocene North America; named genera at Arbuckle Mountain also include taxa restricted to the Pacific Northwest. Leaf margin analysis and leaf area analysis of the East Birch Creek community suggest a warmer and possibly wetter (mean annual temperature 23.4 ± 4.3 °C; mean annual precipitation 206 +89, -63 cm) climate than the Arbuckle Mountain flora (16.4 ± 4.2 °C; 165 +50, -71.4 cm). This research provides a framework for future research on Eocene floristic, environmental, and climatic trends of the Pacific Northwest.

The Kanaka Creek fossil flora (Huntingdon Formation), British Columbia, Canada — paleoenvironment and evidence for Paleocene age using palynology and macroflora

2020 ◽  
Vol 57 (3) ◽  
pp. 348-365
Author(s):  
Rolf W. Mathewes ◽  
David R. Greenwood ◽  
Renée L. Love
Keyword(s):  
British Columbia ◽  
Fungal Spores ◽  
Plant Macrofossils ◽  
Coastal Vegetation ◽  
Mean Annual Precipitation ◽  
Fossil Flora ◽  
Leaf Margin ◽  
Leaf Analysis ◽  
Thermal Maximum ◽  
Margin Analysis

Paleogene sediments of the Huntingdon Formation, a correlative to the Chuckanut Formation of neighbouring Washington State, USA, are exposed in the Greater Vancouver area, British Columbia, Canada. Palynology and plant macrofossils suggest the Kanaka Creek section is Paleocene rather than Eocene in age. Detrital zircon dating is less decisive, yet indicates the Kanaka rocks are no older than Maastrichtian. Analyses of plant macro- and micro-fossils suggest an early to middle Paleocene age for the Kanaka fossil flora. Paleocene indicators include macrofossils such as Platanus bella, Archeampelos, Hamamelites inequalis, and Ditaxocladus, and pollen taxa such as Paraalnipollenites, Triporopollenites mullensis, and Duplopollis. Paleogene taxa such as Woodwardia maxonii, Macclintockia, and Glyptostrobus dominate the flora. Fungal spores including the Late Cretaceous Pesavis parva and the Paleogene Pesavis tagluensis are notable age indicators. Physiognomy of 41 angiosperm leaf morphotypes from Kanaka Creek yields mean annual temperatures in the microthermal to lower mesothermal range (11.2 ± 4.3 to 14.6 ± 2.7 °C from leaf margin analysis; 14.8 ± 2.1 °C from Climate Leaf Analysis Multivariate Program), with mild winters (cold month mean temperature 3.9 ± 3.4 °C). Paleoclimate was cooler than the upper Paleocene and Eocene members of the Chuckanut Formation. Mean annual precipitation is estimated at ∼140 cm with large uncertainties. The Kanaka paleoflora is reconstructed as a mixed conifer–broadleaf forest, sharing common taxa with other western North American Paleocene floras and growing in a temperate moist climate. Kanaka Creek is a rare coastal Paleocene plant locality that provides new insights into coastal vegetation and climate prior to the Paleocene–Eocene Thermal Maximum.

Foliar physiognomic climate estimates for the Late Cretaceous (Cenomanian–Turonian) Lark Quarry fossil flora, central-western Queensland, Australia

2013 ◽  
Vol 61 (8) ◽  
pp. 575 ◽  
Author(s):  
Tamara L. Fletcher ◽  
Patrick T. Moss ◽  
Steven W. Salisbury
Keyword(s):  
Late Cretaceous ◽  
Global Scale ◽  
Mean Annual Precipitation ◽  
Fossil Flora ◽  
Mean Annual Temperature ◽  
Leaf Margin ◽  
Museum Collections ◽  
Growth Season ◽  
Cold Temperatures ◽  
Leaf Analysis

Although there is a broad knowledge of Cretaceous climate on a global scale, quantitative climate estimates for terrestrial localities are limited. One source of terrestrial palaeoproxies is foliar physiognomy. The use of foliar physiognomy to explore Cretaceous assemblages has been limited, and some of its potential sources of error have not been fully explored. Although museum collections house a wealth of material, collection bias toward particular taxa or preservation qualities of specimens further magnifies existing taphonomic bias to cold temperatures. As a result, specific collection for foliar physiognomy can be necessary. Here, we conduct three foliar physiognomic analyses on the early Late Cretaceous Lark Quarry flora and assess the results in the context of other proxies from the same formation. Our results suggest that the climate at the Cenomanian–Turonian boundary in central western Queensland was warm and had high precipitation (leaf-area analysis: 1321 mm + 413 mm – 315 mm mean annual precipitation; leaf-margin analysis: 16.4°C mean annual temperature, 5.3°C binomial sample error; climate leaf-analysis multivariate program: 16 ± 2°C for mean annual temperature, 9-month growth season, 1073 ± 483 mm growth-season precipitation). Our analysis also gave higher mean annual temperature estimates than did a previous analysis by climate leaf-analysis multivariate program, based on museum collections for the Winton Formation.

scholarly journals The Miocene flora of Alum Bluff, Liberty County, Florida

2019 ◽  
Vol 59 (1) ◽  
pp. 75-129 ◽  
Author(s):  
Terry A. Lott ◽  
Steven R. Manchester ◽  
Sarah L. Corbett
Keyword(s):  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Leaf Margin ◽  
Eastern United States ◽  
Plant Fossils ◽  
Minimum Estimate ◽  
Clay Layers ◽  
Climate Analysis ◽  
One New Species ◽  
Cabbage Palm

Abstract The plant fossils of Alum Bluff, northwestern Florida, provide a unique insight into the rarely preserved Miocene flora of the eastern United States. A century has passed since the introductory treatment on the fossil leaf flora of Alum Bluff. More specimens have accumulated over the past two decades, allowing for an updated evaluation of the megafossil flora following a recent study of the palynoflora. The strata consisting of poorly consolidated sand and siltstones with intervening clay layers, here recognized as the Fort Preston Formation of the Alum Bluff Group, are considered to be of Barstovian age (16.3–13.6 Ma), based on co-occurring mammalian remains. Here we recognize 36 kinds of leaves and 10 kinds of fruits and seeds, giving a minimum estimate of at least one fungus, one fern, one gymnosperm, 38 angiosperms and 7 unknowns. We also report one new species and two new combinations. These taxa augment those already reported based on pollen from the same strata, allowing us to portray the vegetation as elm-hickory-cabbage palm forest occurring near the coastline in a deltaic, pro-deltaic, or intertidal shore face environment. The results of a climate analysis of the Alum Bluff flora, using leaf margin and leaf area, give estimates of 19.0°C mean annual temperature and 116.0 cm mean annual precipitation.

scholarly journals Post-Pliocene establishment of the present monsoonal climate in SW China: evidence from the late Pliocene Longmen megaflora

2013 ◽  
Vol 9 (2) ◽  
pp. 1675-1701 ◽  
Author(s):  
T. Su ◽  
F. M. B. Jacques ◽  
R. A. Spicer ◽  
Y.-S. Liu ◽  
Y.-J. Huang ◽  
...  
Keyword(s):  
Tibet Plateau ◽  
Leaf Margin ◽  
Late Pliocene ◽  
Leaf Analysis ◽  
Asian Winter Monsoon ◽  
Monsoon Index ◽  
Coexistence Approach ◽  
Western Yunnan ◽  
Qinghai Tibet Plateau ◽  
Margin Analysis

Abstract. The paleoclimate of the late Pliocene Longmen flora from Yongping County located at the southeastern boundary of the Qinghai-Tibet Plateau was reconstructed using two leaf physiognomy based methods, i.e. Leaf Margin Analysis (LMA) and Climate Leaf Analysis Multivariate Program (CLAMP), to understand the paleoclimate condition and geographical pattern of monsoonal climate in southwestern China during the late Pliocene. The mean annual temperatures (MATs) estimated by LMA and CLAMP are 17.4 ± 3.3 °C and 17.4 ± 1.3 °C, respectively, compared with 15.9 °C at present. Meanwhile, the growing season precipitation (GSP) estimated by CLAMP is 1735.5 ± 217.7 mm in the Longmen flora, compared with 986.9 mm nowadays. The calculated monsoon index (MSI) of the Longmen flora is significantly lower than that of today. These results appear consistent with previous studies based on the coexistence approach (CA), and further suggest that there was a slightly warmer and much wetter climate during the late Pliocene than the present climate in western Yunnan. We conclude that the significant change of the monsoonal climate might have been resulted from the continuous uplift of mountains in western Yunnan, as well as the intensification of eastern Asian winter monsoon, both occurring concurrently in the post-Pliocene period.

scholarly journals Complex community responses underpin biodiversity change following invasion

2021 ◽  
Author(s):  
Alessandra R. Kortz ◽  
Anne E. Magurran
Keyword(s):  
Invasive Species ◽  
Species Richness ◽  
Spatial Scales ◽  
Species Abundance ◽  
Ecological Systems ◽  
Multi Scale ◽  
Mechanistic Approach ◽  
Α Diversity ◽  
Biodiversity Change ◽  
Insight Into

AbstractHow do invasive species change native biodiversity? One reason why this long-standing question remains challenging to answer could be because the main focus of the invasion literature has been on shifts in species richness (a measure of α-diversity). As the underlying components of community structure—intraspecific aggregation, interspecific density and the species abundance distribution (SAD)—are potentially impacted in different ways during invasion, trends in species richness provide only limited insight into the mechanisms leading to biodiversity change. In addition, these impacts can be manifested in distinct ways at different spatial scales. Here we take advantage of the new Measurement of Biodiversity (MoB) framework to reanalyse data collected in an invasion front in the Brazilian Cerrado biodiversity hotspot. We show that, by using the MoB multi-scale approach, we are able to link reductions in species richness in invaded sites to restructuring in the SAD. This restructuring takes the form of lower evenness in sites invaded by pines relative to sites without pines. Shifts in aggregation also occur. There is a clear signature of spatial scale in biodiversity change linked to the presence of an invasive species. These results demonstrate how the MoB approach can play an important role in helping invasion ecologists, field biologists and conservation managers move towards a more mechanistic approach to detecting and interpreting changes in ecological systems following invasion.

scholarly journals Total column water vapour measurements from GOME-2 MetOp-A and MetOp-B

2014 ◽  
Vol 7 (3) ◽  
pp. 3021-3073 ◽  
Author(s):  
M. Grossi ◽  
P. Valks ◽  
D. Loyola ◽  
B. Aberle ◽  
S. Slijkhuis ◽  
...  
Keyword(s):  
Water Vapour ◽  
Optical Absorption Spectroscopy ◽  
Retrieval Algorithm ◽  
Data Sets ◽  
Vertical Column ◽  
Data Set ◽  
Vertical Column Density ◽  
Data Processor ◽  
Climate Analysis ◽  
Total Column

Abstract. The knowledge of the total column water vapour (TCWV) global distribution is fundamental for climate analysis and weather monitoring. In this work, we present the retrieval algorithm used to derive the operational TCWV from the GOME-2 sensors and perform an extensive inter-comparison and validation in order to estimate their absolute accuracy and long-term stability. We use the recently reprocessed data sets retrieved by the GOME-2 instruments aboard EUMETSAT's MetOp-A and MetOp-B satellites and generated by DLR in the framework of the O3M-SAF using the GOME Data Processor (GDP) version 4.7. The retrieval algorithm is based on a classical Differential Optical Absorption Spectroscopy (DOAS) method and combines H2O/O2 retrieval for the computation of the trace gas vertical column density. We introduce a further enhancement in the quality of the H2O column by optimizing the cloud screening and developing an empirical correction in order to eliminate the instrument scan angle dependencies. We evaluate the overall consistency between about 8 months measurements from the newer GOME-2 instrument on the MetOp-B platform with the GOME-2/MetOp-A data in the overlap period. Furthermore, we compare GOME-2 results with independent TCWV data from ECMWF and with SSMIS satellite measurements during the full period January 2007–August 2013 and we perform a validation against the combined SSM/I + MERIS satellite data set developed in the framework of the ESA DUE GlobVapour project. We find global mean biases as small as ± 0.03 g cm−2 between GOME-2A and all other data sets. The combined SSM/I-MERIS sample is typically drier than the GOME-2 retrievals (−0.005 g cm−2), while on average GOME-2 data overestimate the SSMIS measurements by only 0.028 g cm−2. However, the size of some of these biases are seasonally dependent. Monthly average differences can be as large as 0.1 g cm−2, based on the analysis against SSMIS measurements, but are not as evident in the validation with the ECMWF and the SSM/I + MERIS data. Studying two exemplary months, we estimate regional differences and identify a very good agreement between GOME-2 total columns and all three independent data sets, especially for land areas, although some discrepancies over ocean and over land areas with high humidity and a relatively large surface albedo are also present.

scholarly journals Altitudinal Vascular Plant Richness and Climate Change in the Alpine Zone of the Lefka Ori, Crete

Diversity ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 22
Author(s):  
George Kazakis ◽  
Dany Ghosn ◽  
Ilektra Remoundou ◽  
Panagiotis Nyktas ◽  
Michael A. Talias ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Richness ◽  
Spatial Scales ◽  
Vascular Plant ◽  
Monitoring Network ◽  
Mediterranean Area ◽  
Mean Annual Temperature ◽  
High Mountain ◽  
Species Loss ◽  
Total Species Richness

High mountain zones in the Mediterranean area are considered more vulnerable in comparison to lower altitudes zones. Lefka Ori massif, a global biodiversity hotspot on the island of Crete is part of the Global Observation Research Initiative in Alpine Environments (GLORIA) monitoring network. The paper examines species and vegetation changes with respect to climate and altitude over a seven-year period (2001–2008) at a range of spatial scales (10 m Summit Area Section-SAS, 5 m SAS, 1 m2) using the GLORIA protocol in a re-survey of four mountain summits (1664 m–2339 m). The absolute species loss between 2001–2008 was 4, among which were 2 endemics. At the scale of individual summits, the highest changes were recorded at the lower summits with absolute species loss 4 in both cases. Paired t-tests for the total species richness at 1 m2 between 2001–2008, showed no significant differences. No significant differences were found at the individual summit level neither at the 5 m SAS or the 10 m SAS. Time series analysis reveals that soil mean annual temperature is increasing at all summits. Linear regressions with the climatic variables show a positive effect on species richness at the 5 m and 10 m SAS as well as species changes at the 5 m SAS. In particular, June mean temperature has the highest predictive power for species changes at the 5 m SAS. Recorded changes in species richness point more towards fluctuations within a plant community’s normal range, although there seem to be more significant diversity changes in higher summits related to aspects. Our work provides additional evidence to assess the effects of climate change on plant diversity in Mediterranean mountains and particularly those of islands which remain understudied.

Consistency of teleseismic reporting since 1963

1982 ◽  
Vol 72 (1) ◽  
pp. 93-111
Author(s):  
R. E. Habermann
Keyword(s):  
Detection System ◽  
Active Regions ◽  
The United States ◽  
Western Hemisphere ◽  
Cumulative Number ◽  
Data Set ◽  
Seismicity Rate ◽  
Teleseismic Data ◽  
Entire World ◽  
Seismicity Rate Changes

abstract Changes in the rate of occurrence of smaller events have been recognized in the rupture zones of upcoming large earthquakes in several postearthquake and one preearthquake study. A data set in which a constant portion of the events in any magnitude band are consistently reported through time is crucial for the recognition of seismicity rate changes which are real (related to some process change in the earth). Such a data set is termed a homogeneous data set. The consistency of reporting of earthquakes in the NOAA Hypocenter Data File (HDF) since 1963 is evaluated by examining the cumulative number of events reported as a function of time for the entire world in eight magnitude bands. It is assumed that the rate of occurrence of events in the entire world is roughly constant on the time scale examined here because of the great size of the worldwide earthquake production system. The rate of reporting of events with magnitudes above mb = 4.5 has been constant or increasing since 1963. Significant decreases in the number of events reported per month in the magnitude bands below mb = 4.4 occurred during 1968 and 1976. These decreases are interpreted as indications of decreases in detection of events for two reasons. First, they occur at times of constant rates of occurrence and reporting of larger events. Second, the decrease during the late 1960's has also been recognized in the teleseismic data reported by the International Seismological Centre (ISC). This suggests that the decrease in the number of small events reported was related to facets of the earthquake reporting system which the ISC and NOAA share. The most obvious candidate is the detection system. During 1968, detection decreased in the United States, Central and South America, and portions of the South Pacific. This decrease is probably due to the closure of the VELA arrays, BMO, TFO, CPO, UBO, and WMO. During 1976, detection decreased in most of the seismically active regions of the western hemisphere, as well as in the region between Kamchatka and Guam. The cause of this detection decrease is unclear. These detection decreases seriously affect the amount of homogeneous background period available for the study of teleseismic seismicity rate changes. If events below the minimum magnitude of homogeneity are eliminated from the teleseismic data sets the resulting small numbers of events render many regions unsuitable for study. Many authors have reported seismicity rate decreases as possible precursors to great earthquakes. Few of these authors have considered detection decreases as possible explanations for their results. This analysis indicates that such considerations cannot be avoided in studies of teleseismic data.

scholarly journals The freshwater diaptomid copepod fauna (Crustacea: Copepoda: Diaptomidae) of the Western Ghats of Maharashtra with notes on distribution, species richness and ecology

2015 ◽  
Author(s):  
Mihir R. Kulkarni ◽  
Kalpana Pai
Keyword(s):  
Species Richness ◽  
Western Ghats ◽  
Mean Annual Temperature ◽  
Sampling Effort ◽  
Calanoid Copepods ◽  
Anthropogenic Pressures ◽  
Temporary Habitats ◽  
Ecological Aspects ◽  
Diaptomid Copepods ◽  
The Western Ghats

<p>The diversity of many invertebrate taxa from Western Ghats of Maharashtra remains unknown due to lack of systematic studies. We studied freshwater calanoid copepods from this region, and found eleven species of diaptomid copepods in 180 samples collected from 80 sites in the study area. Most of these are new records for this region. The observed fauna includes Oriental, Gondwanan, Palaearctic and Indian endemic taxa. Locality data for all the observed species, along with notes on some ecological aspects of the sampled sites are provided. Non-parametric estimates of species richness for the region suggested an overall adequacy of sampling effort, and probable missing out of some species from habitats with longer hydroperiod. Hydroperiod, depth, electrical conductivity, altitude, mean annual temperature and latitude largely influenced the distribution of species in the study area. Co-occurrences of species were overall rare but more common in temporary habitats. Assemblages of diaptomid copepods restricted to certain sites were identified. The importance of temporary habitats is discussed in the light of their species richness, faunal composition and the increasing anthropogenic pressures they face.</p>

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