Forest Composition, Structure, and Disturbance History of the Alan Seeger Natural Area, Huntington County, Pennsylvania

1994 ◽  
Vol 121 (3) ◽  
pp. 277 ◽  
Author(s):  
Gregory J. Nowacki ◽  
Marc D. Abrams
2019 ◽  
Vol 35 (03) ◽  
pp. 95-107 ◽  
Author(s):  
Sarayudh Bunyavejchewin ◽  
Aroon Sinbumroong ◽  
Benjamin L. Turner ◽  
Stuart J. Davies

AbstractIn 2000, we established a 24-ha plot in Peninsular Thailand to investigate how forest composition, structure and dynamics vary with spatial heterogeneity in resource availability. Detailed soil and topographic surveys were used to describe four edaphic habitats in the plot. Disturbance history was inferred from historical records and floristic analysis. The plot included >119 000 trees ≥1 cm dbh in 578 species, and was recensused in 2010. Species distributions, floristic turnover, stand structure, demographic rates and biomass dynamics were strongly influenced by heterogeneity in soils, topography and disturbance history. Over 75% of species were aggregated on specific edaphic habitats leading to strong compositional turnover across the plot. Soil chemistry more strongly affected species turnover than topography. Forest with high biomass and slow dynamics occurred on well-drained, low fertility ridges. The distribution and size structure of pioneer species reflected habitat-specific differences in disturbance history. Overall, above-ground biomass (AGB) increased by 0.64 Mg ha−1 y−1, from 385 to 392 Mg ha−1, an increase that was entirely attributable to recovery after natural disturbance. Forest composition and stand structure, by reflecting local disturbance history, provide insights into the likely drivers of AGB change in forests. Predicting future changes in tropical forests requires improved understanding of how soils and disturbance regulate forest dynamics.


Author(s):  
O. Mousis ◽  
D. H. Atkinson ◽  
R. Ambrosi ◽  
S. Atreya ◽  
D. Banfield ◽  
...  

AbstractRemote sensing observations suffer significant limitations when used to study the bulk atmospheric composition of the giant planets of our Solar System. This impacts our knowledge of the formation of these planets and the physics of their atmospheres. A remarkable example of the superiority of in situ probe measurements was illustrated by the exploration of Jupiter, where key measurements such as the determination of the noble gases’ abundances and the precise measurement of the helium mixing ratio were only made available through in situ measurements by the Galileo probe. Here we describe the main scientific goals to be addressed by the future in situ exploration of Saturn, Uranus, and Neptune, placing the Galileo probe exploration of Jupiter in a broader context. An atmospheric entry probe targeting the 10-bar level would yield insight into two broad themes: i) the formation history of the giant planets and that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. An atmospheric probe could represent a significant ESA contribution to a future NASA New Frontiers or flagship mission to be launched toward Saturn, Uranus, and/or Neptune.


1936 ◽  
Vol 14 (3) ◽  
pp. 127-130 ◽  
Author(s):  
R. T. Leiper

In an article on “The Longevity of Diphyllobothrium latum” published in 1935 in the “Recueil des Travaux dédié au 25-me Anniversaire Scientifique du Professeur Eugène Paviosky 1909−1934”, it is suggested that present day conceptions regarding the longevity of this parasite are erroneous and that multiple successive infections are frequently attributed to a single long-lived specimen. Ward gives a detailed review and analysis of the evidence hitherto published both in general works and special monographs and cites as specially important the history of the occurrence of this species on the North American continent. He points out that the age of the parasite is regularly based on the statement that the host had not been in an infected region for the period indicated. To this statement, Ward puts forward the objections that the distribution of the parasite and the natural occurrence of plerocercoid carrying fish are far more extensive than was formerly suspected and, further, that infected fish are distributed commercially as food to regions far outside their natural area of distribution. He also refers to certain records which seem to indicate that there is a “period of inactivity” during the adult life of the parasite and suggests that its alleged occurrence throws doubt upon the supposed longevity of the parasite. In support of this contention, he cites, as a typical instance, a case of human infection with Diphyllobothrium latum reported by me (Leiper, 1928) as a “cryptic infection”; regarding which he erroneously states that I believed was “latent” for 5 years.


Check List ◽  
2016 ◽  
Vol 12 (5) ◽  
pp. 1964
Author(s):  
Omar Machado Entiauspe-Neto ◽  
Tângela Denise Perleberg ◽  
Marco Antonio de Freitas

Faunistic inventories regarding natural history of amphibians and reptiles are considered scarce and very little is known about their assemblages in urban areas; the Pampas morphoclimatic domain, also known as Uruguayan Savannah or Southern Grasslands, is also poorly known regarding their faunal composition.  Herein, we present a checklist of 16 amphibian and 20 reptile species recorded over a course of four years in the Instituto Federal de Educação, Ciências e Tecnologia, Câmpus Pelotas-Visconde da Graça, in Pelotas, Rio Grande do Sul, Brazil. We also present data on natural history and discuss conservation efforts to be undertaken in the area, in one of the least preserved and known Brazilian morphoclimatic domains, providing insights into urban herpetofaunal diversity patterns and showing the importance of modified areas in its conservation.


Biotropica ◽  
2021 ◽  
Author(s):  
Rodrigue Batumike ◽  
Gérard Imani ◽  
Benjamin Bisimwa ◽  
Hwaba Mambo ◽  
John Kalume ◽  
...  

2021 ◽  
Author(s):  
Margot Nelson ◽  
Michael Antonioni ◽  
Vincent Santucci ◽  
Justin Tweet

Oxon Run Parkway (OXRN) is a 51-hectare (126-acre) natural area within Washington, D.C. administered by the National Park Service under National Capital Parks East (NACE). The original plan called for a road, slated to follow Oxon Run stream, but this never came to fruition; despite this, the moniker stuck. The majority of the original Oxon Run Parkway is managed by the District of Columbia. The section of Oxon Run Parkway under NPS jurisdiction contains wetlands and forests, as well as the only McAteean magnolia bogs still remaining in the District. The lower Cretaceous Potomac Group, known as one of the few dinosaur-bearing rock units on the east coast of North America, crops out within Oxon Run. One of the most prevalent fossil-bearing resources are the siderite, or “bog iron” sandstone slabs that sometimes preserve the footprints or trackways of various vertebrates, including dinosaurs. Such trackways have been reported from Potomac Group outcrops throughout the Atlantic Coastal Plain of Maryland and Virginia. In 2019, National Capital Parks-East took possession of such a track, referred to a dinosaur, collected by paleontologist Dr. Peter Kranz. This report was compiled after a paleontological survey of Oxon Run Parkway and is intended as a supplement to the National Capital Parks East Paleontological Resource Inventory (Nelson et al. 2019). This report contains information on the history of Oxon Run Parkway and its geology, as well as discussion of the fossil track.


2018 ◽  
Vol 50 ◽  
pp. 91-97 ◽  
Author(s):  
Quan Zhou ◽  
Hang Shi ◽  
Chengpo Liu ◽  
Kerong Zhang ◽  
Quanfa Zhang ◽  
...  

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