scholarly journals Historic Fire Regime of an Upland Oak Forest in South-Central North America

Fire Ecology ◽  
2010 ◽  
Vol 6 (3) ◽  
pp. 45-61 ◽  
Author(s):  
Ryan D. DeSantis ◽  
Stephen W. Hallgren ◽  
David W. Stahle
Keyword(s):  
North America ◽  
Fire Regime ◽  
Oak Forest ◽  
South Central

The Neogene transition from C3 to C4 grasslands in North America: assemblage analysis of fossil phytoliths

Paleobiology ◽  
2011 ◽  
Vol 37 (1) ◽  
pp. 50-71 ◽  
Author(s):  
Caroline A. E. Strömberg ◽  
Francesca A. McInerney
Keyword(s):  
North America ◽  
Great Plains ◽  
Late Miocene ◽  
Vegetation Change ◽  
Stable Carbon Isotopes ◽  
Fire Regime ◽  
Tooth Enamel ◽  
Regional Scale ◽  
Grassland Ecosystems ◽  
Isotopic Records

The rapid ecological expansion of grasses with C4 photosynthesis at the end of the Neogene (8–2 Ma) is well documented in the fossil record of stable carbon isotopes. As one of the most profound vegetation changes to occur in recent geologic time, it paved the way for modern tropical grassland ecosystems. Changes in CO2 levels, seasonality, aridity, herbivory, and fire regime have all been suggested as potential triggers for this broadly synchronous change, long after the evolutionary origin of the C4 pathway in grasses. To date, these hypotheses have suffered from a lack of direct evidence for floral composition and structure during this important transition. This study aimed to remedy the problem by providing the first direct, relatively continuous record of vegetation change for the Great Plains of North America for the critical interval (ca. 12–2 Ma) using plant silica (phytolith) assemblages.Phytoliths were extracted from late Miocene-Pliocene paleosols in Nebraska and Kansas. Quantitative phytolith analysis of the 14 best-preserved assemblages indicates that habitats varied substantially in openness during the middle to late Miocene but became more uniformly open, corresponding to relatively open grassland or savanna, during the late Miocene and early Pliocene. Phytolith data also point to a marked increase of grass short cells typical of chloridoid and other potentially C4 grasses of the PACMAD clade between 8 and 5 Ma; these data suggest that the proportion of these grasses reached up to ∼50–60% of grasses, resulting in mixed C3-C4 and highly heterogeneous grassland communities by 5.5 Ma. This scenario is consistent with interpretations of isotopic records from paleosol carbonates and ungulate tooth enamel. The rise in abundance of chloridoids, which were present in the central Great Plains since the early Miocene, demonstrates that the “globally” observed lag between C4 grass evolution/taxonomic diversification and ecological expansion occurred at the regional scale. These patterns of vegetation alteration imply that environmental change during the late Miocene-Pliocene played a major role in the C3-C4 shift in the Great Plains. Specifically, the importance of chloridoids as well as a decline in the relative abundance of forest indicator taxa, including palms, point to climatic drying as a key trigger for C4 dominance.

Amia cf. pattersoni from the Paleocene Paskapoo Formation of Alberta

2000 ◽  
Vol 37 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Lance Grande ◽  
Li Guo-Qing ◽  
Mark VH Wilson
Keyword(s):  
North America ◽  
Fish Fauna ◽  
Taxonomic Diversity ◽  
Geographic Range ◽  
Green River Formation ◽  
Early Eocene ◽  
Freshwater Teleost ◽  
Additional Material ◽  
Green River ◽  
South Central

A well-prepared anterior half of an amiid skull from the Late Paleocene Paskapoo Formation of south-central Alberta is described. The specimen is either very closely related to, or conspecific with, Amia pattersoni Grande and Bemis, 1998, from the Early Eocene Green River Formation of Wyoming. We leave the specimen as Amia cf. pattersoni until additional material is found to further clarify its relationships. Amia cf. pattersoni is the oldest known specimen clearly identifiable as belonging to the genus Amia (sensu Grande and Bemis, 1998), and the Paskapoo species extends the known geographic range of Amia both northward and westward. The fish assemblage of the Paskapoo Formation represents the most diverse freshwater Paleocene fish fauna known from North America. Based on comparisons of sample size and relative taxonomic diversity to the better known Green River Formation localities of Wyoming, we predict that further collecting will substantially increase the known diversity of the Paskapoo fauna. The Paskapoo Formation, therefore, has great potential to continue adding to the meager knowledge of pre-Eocene freshwater teleost diversity in North America.

Paleomagnetism of the Triassic Nikolai Greenstone, McCarthy Quadrangle, Alaska

1977 ◽  
Vol 14 (11) ◽  
pp. 2578-2592 ◽  
Author(s):  
J. W. Hillhouse
Keyword(s):  
British Columbia ◽  
High Temperature ◽  
North America ◽  
Vertical Axis ◽  
Upper Triassic ◽  
Present Position ◽  
Stable Component ◽  
South Central ◽  
Early Mesozoic ◽  
Lamellar Texture

Paleomagnetic evidence indicates that the extensive early Mesozoic basalt field near McCarthy, south-central Alaska, originated far south of its present position relative to North America. Results obtained from the Middle and (or) Upper Triassic Nikolai Greenstone suggest that those basalts originated within 15° of the paleoequator. This position is at least 27° (3000 km) south of the Upper Triassic latitude predicted for McCarthy on the basis of paleomagnetic data from continental North America. The Nikolai pole, as determined from 50 flows sampled at 5 sites, is at 2.2° N, 146.1° E (α95 = 4.8°). The polarity of the pole is ambiguous, because the corresponding magnetic direction has a low inclination and a westerly declination. Therefore, the Nikolai may have originated near 15° N latitude or, alternatively, as far south as 15° S latitude. In addition to being displaced northward, the Nikolai block has been rotated roughly 90° about the vertical axis. A measure of the reliability of this pole is provided by favorable results from the following tests: (1) Within one stratigraphic section, normal and reversed directions from consecutive flows are antipolar. (2) Consistent directions were obtained from sites 30 km apart. (3) Application of the fold test indicated the magnetization was acquired before the rocks were folded. (4) The magnetizations of several pilot specimens are thermally stable up to 550 °C. The stable component is probably carried by magnetite with lamellar texture, a primary feature commonly acquired by a basalt at high temperature during initial cooling of the magma. Geologic and paleomagnetic evidence indicates that the Nikolai is allochthonous to Alaska and that, together with associated formations in southern Alaska and British Columbia, it is part of a now disrupted equatorial terrane.

Effects of Prescribed Fire on Site Occupancy of Allegheny Woodrats (Neotoma magister) in a Mixed-Oak Forest in South-Central Pennsylvania

2021 ◽  
Vol 41 (2) ◽  
Author(s):  
Christopher L. Hauer ◽  
Jamie Shinskie ◽  
Rebecca Picone ◽  
David McNaughton ◽  
Jon Dimitri Lambrinos ◽  
...  
Keyword(s):  
Prescribed Fire ◽  
Site Occupancy ◽  
Oak Forest ◽  
Neotoma Magister ◽  
South Central ◽  
Central Pennsylvania

Wild Pigs in South-Central North America

2019 ◽  
pp. 347-368
Author(s):  
Joshua A. Gaskamp ◽  
James C. Cathey ◽  
Billy Higginbotham ◽  
Michael J. Bodenchuk
Keyword(s):  
North America ◽  
Wild Pigs ◽  
South Central

Mediterranean fire regime effects on pine-oak forest landscape mosaics under global change in NE Spain

2016 ◽  
Vol 135 (2) ◽  
pp. 403-416 ◽  
Author(s):  
Assu Gil-Tena ◽  
Núria Aquilué ◽  
Andrea Duane ◽  
Miquel De Cáceres ◽  
Lluís Brotons
Keyword(s):  
Global Change ◽  
Fire Regime ◽  
Oak Forest ◽  
Forest Landscape ◽  
Landscape Mosaics ◽  
Ne Spain

Arenig (Lower Ordovician) conodonts and biozonation in the eastern Siljan district, central Sweden

1994 ◽  
Vol 68 (6) ◽  
pp. 1350-1368 ◽  
Author(s):  
Anita M. Löfgren
Keyword(s):  
North America ◽  
The Other ◽  
South Central ◽  
Lower Ordovician ◽  
Conodont Zone ◽  
Local Base ◽  
Reference Section ◽  
Zones And Subzones

Based on biostratigraphic investigations in the eastern Siljan district, central Sweden, and combined with earlier studies at Hunneberg, south-central Sweden, it is shown that the early post-Tremadoc-age Paroistodus proteus conodont Zone can be divided into four successive subzones. These are, in ascending order: the Drepanoistodus aff. D. amoenus Subzone; the Tripodus Subzone; the Paracordylodus gracilis Subzone; and the Oelandodus elongatus-Acodus deltatus deltatus Subzone. The lowermost of the subzones is a concurrent range zone, with its reference section at Storeklev, Hunneberg, and the other three interval zones with the reference section at Sjurberg in the eastern Siljan district. Correlations between these two areas, as well as with the Flåsjö area, Jämtland, the Finngrundet core, and some other areas, are discussed, and it is concluded that the Drepanoistodus aff. D. amoenus Subzone and the Tripodus Subzone together correspond to the Megistaspis (Ekeraspis) armata trilobite Zone, and occur below the Hunnegraptus copiosus graptolite Zone. The Paracordylodus gracilis Subzone is equivalent with the lower part of the Megistaspis (Varvaspis) planilimbata trilobite Zone, and may correspond to the Hunnegraptus copiosus Zone. The uppermost subzone, the Oelandodus elongatus-Acodus deltatus deltatus Subzone, equals the upper part of the M. (V.) planilimbata Zone, and the local base of the Tetragraptus phyllograptoides graptolite Zone is close to the base of this conodont subzone. The last occurrences of T. phyllograptoides are close to the top of this conodont subzone. Also included in the investigation are the uppermost part of the uppermost Tremadoc Paltodus deltifer Zone and the conodont zones overlying the P. proteus Zone in the eastern Siljan district, the Prioniodus elegans Zone and the Oepikodus evae Zone; the latter zone corresponds to the trilobite zones of Megalaspides (M.) dalecarlicus and Megistaspis (Varvaspis) estonica. A few samples from the superimposed Baltoniodus triangularis, B. navis, and Paroistodus originalis Zones have been investigated and are described as well. The correlation of these conodont zones and subzones with those of areas outside Baltoscandia, particularly North America, is also discussed.

Identifying areas of wetland and wind turbine overlap in the south-central Great Plains of North America

2020 ◽  
Vol 35 (9) ◽  
pp. 1995-2011
Author(s):  
L. J. Heintzman ◽  
E. S. Auerbach ◽  
D. H. Kilborn ◽  
S. M. Starr ◽  
K. R. Mulligan ◽  
...  
Keyword(s):  
North America ◽  
Wind Turbine ◽  
Great Plains ◽  
The South ◽  
South Central

scholarly journals Amblyomma rotundatum (Koch, 1844) (Acari: Ixodidae) two-host life-cycle on Viperidae snakes

2010 ◽  
Vol 19 (3) ◽  
pp. 174-178 ◽  
Author(s):  
Daniel Sobreira Rodrigues ◽  
Ricardo Maciel ◽  
Lucas Maciel Cunha ◽  
Romário Cerqueira Leite ◽  
Paulo Roberto de Oliveira
Keyword(s):  
Life Cycle ◽  
North America ◽  
Relative Humidity ◽  
Total Duration ◽  
Ixodid Tick ◽  
Natural Conditions ◽  
South Central ◽  
Controlled Conditions ◽  
In Captivity ◽  
Host Life

Amblyomma rotundatum is an ixodid tick that infests ectothermic animals and reproduces exclusively by parthenogenesis. This tick has been frequently reported to infest reptiles and amphibians, under natural conditions and sometimes in captivity. It was described in Brazil and several other countries of South, Central and North America. Although many studies have reported aspects of its biology, none of them has used regularly either ophidian as hosts, or controlled temperature, humidity and luminosity for parasitic stages. The objective of this experiment was to study the life cycle of A. rotundatum feeding on Viperidae snakes under room controlled conditions at 27 ± 1 ºC temperature, 85 ± 10% relative humidity and 12:12 hours photoperiod for parasitic stages, and under B.O.D incubator conditions at 27 ± 1 ºC temperature, 85 ± 10% relative humidity and scotophase for non-parasitic stages. The total duration of the life cycle ranged from 56 to 163 days (mean of 105 days). Two-host life cycle was observed for most of the ixodid population studied.

Late Cambrian ptychaspidid trilobites from western Utah: implications for trilobite systematics and biostratigraphy

2005 ◽  
Vol 142 (4) ◽  
pp. 377-398 ◽  
Author(s):  
J. M. ADRAIN ◽  
S. R. WESTROP
Keyword(s):  
North America ◽  
Distinct Species ◽  
Western North America ◽  
Closely Related Species ◽  
Widespread Species ◽  
Late Cambrian ◽  
South Central ◽  
New Information ◽  
The Family ◽  
Notch Peak

The Notch Peak Formation (Late Cambrian, Sunwaptan) of western Utah yields diverse silicified trilobite faunas that provide new information on the anatomy of many taxa. The family Ptychaspididae Raymond, 1924, is represented by species of Keithiella Rasetti, 1944; Idiomesus Raymond, 1924; Euptychaspis Ulrich in Bridge, 1931; and Macronoda Lochman, 1964. At least four species are new, of which E. lawsonensis and M. notchpeakensis are named formally. Much previous work on Late Cambrian trilobites has emphasized biostratigraphic utility and the recognition of geographically widespread species. Data from new silicified collections indicate that this approach is difficult to justify because many putative ‘index species’ actually represent a plexus of closely related species whose biostratigraphic significance has yet to be determined. One such plexus is represented by E. kirki Kobayashi, 1935, whose previously reported occurrences in Texas, Oklahoma, Utah, Nevada and northern Canada record at least four distinct species. Similarly, Macronoda can now be shown to consist of at least five late Sunwaptan species in south-central and western North America.

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