Ammophila Invasion Ecology and Dune Restoration on the West Coast of North America

Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 629
Author(s):  
Andrea J. Pickart

The invasive ecosystem engineer Ammophila arenaria, native to Europe, was first introduced to California (USA) in 1896. More than a century later, it has come to dominate coastal foredune vegetation on the west coast of North America to the near exclusion of native species. A. arenaria builds a narrow, steep, peaked, and densely vegetated foredune, in contrast to the broad, more sparsely vegetated foredunes built by the native Elymus mollis. As such, it has modified dune processes by fixing the foredune and disrupting exchange of sediment between the beach, foredune, and dunefield. In the 1930s the congener A. breviligulata, native to the east coast and Great Lakes USA, was first introduced to Oregon, and has been displacing A. arenaria in southern Washington. Ammophila spp. have drastically reduced biodiversity, outcompeting native plant species, and displacing both invertebrate and vertebrate species. Restoration of west coast dunes through the removal of Ammophila began in the 1990s. Methods usually consist of one or a combination of manual digging, burning/herbicides, or excavation with heavy equipment. There are benefits and disadvantages to each method. Manual removal has proven most effective at restoring foredune form and process but is expensive. Excavation and herbicides may result in the loss of foredune morphology. Managers must articulate goals carefully before selecting restoration methods.

Polar Record ◽  
2016 ◽  
Vol 52 (4) ◽  
pp. 474-498
Author(s):  
W. Barr

ABSTRACTSince the Admiralty's instructions to Captain Sir John Franklin for his attempt at a transit of the northwest passage in HMS Erebus and Terror in 1845 specified that he should proceed to Cape Walker at the northeastern tip of Russell Island, and head southwest from there to the waterways already explored along the mainland coast of North America, as far as ice conditions and any intervening land permitted, it was natural that the first search expedition to come within striking distance of Cape Walker, should make this one of the starting points of its detailed search. This was the squadron of Captain Horatio Austin that wintered off the northeast coast of Griffith Island in 1850–1851. Following his orders, in the spring of 1851 Captain Erasmus Ommanney of HMS Assistance set off with an impressive cavalcade of seven man-hauled sledges, most of them support sledges. From Cape Walker Lt. William Browne searched the east coast of Prince of Wales Island, that is the western shores of Peel Sound while Ommanney himself and Lt. Sherard Osborn searched the west coast of Prince of Wales Island, that is the east shore of McClintock Channel. No traces of Franklin's expedition were found. Their conclusions were that both McClintock Channel and Peel Sound were permanently blocked with ice, and that Franklin's ships could not have travelled south by either route. While the conclusion as regards McClintock Channel was absolutely correct, that with regard to Peel Sound was incorrect. This must have been the route whereby Erebus and Terror had reached the vicinity of King William Island, and the conclusion that Peel Sound never cleared of ice was very unfortunate in that the next search expedition dispatched by the Admiralty, that of Captain Sir Edward Belcher in 1852–1854 made no attempt to penetrate south, when it is possible that Peel Sound was clear of ice.


2019 ◽  
Vol 6 (4) ◽  
pp. 190153 ◽  
Author(s):  
Myles H. M. Menz ◽  
Brian V. Brown ◽  
Karl R. Wotton

The seasonal migration of huge numbers of hoverflies is frequently reported in Europe from mountain passes or spurs of land. The movement of such large numbers of beneficial insects is thought to provide significant ecosystem services in terms of pollination and pest control. Observations from the East Coast of the USA during the 1920s indicate the presence of migratory life histories among some hoverfly species there, but 90 years have now passed since the last reported observation of hoverfly migration in the USA. Here, we analyse video footage taken during a huge northward migration of hoverflies on 20 April 2017 on the West Coast of California. The quantification of migrant numbers from this footage allows us to estimate the passage of over 100 000 hoverflies in half an hour over a 200 m section of headland in Montaña de Oro State Park (San Luis Obispo County). Field collections and analysis of citizen science data indicate different species from the previously reported Eristalis tenax migrations on the East Coast of the USA and provide evidence for migration among North American hoverflies. We wish to raise awareness of this phenomenon and suggest approaches to advance the study of hoverfly migration in North America and elsewhere.


2020 ◽  
Author(s):  
John Hunter

Abstract. An analysis of the viability of the Witness King Tides Project (hereafter called WKT) using data from the GESLA-2 database of quasi-global tide-gauge records is described. The results indicate regions of the world where WKT should perform well (e.g. the west coast of the USA) and others where it would not (e.g. the east coast of North America). Recommendations are made both for assessments that should be made prior to a WKT project, and also for an alternative to WKT projects.


1985 ◽  
Vol 12 (3) ◽  
pp. 207-216 ◽  
Author(s):  
Daniel W. Gade

One of the most isolated islands on Earth, Rodrigues in the Indian Ocean stands as a modern-day ‘morality play’ of the consequences of environmental abuse. This tiny piece of land on the fringe of the tropics, emerged as an island through volcanic action some 1.5 million years ago, and acquired its biota mainly by long-distance dispersal from the west. Rodrigues was not inhabited by any people until 1691, and since then has always been administered from Mauritius which lies 650 km to the west.Burning, browsing, and woodcutting, have almost completely removed the indigenous forest. Close to a third of the native plant species have disappeared, and another third are on the brink of extinction. Giant land-tortoises, sea-turtles, and the Dugong, have vanished. Only two of the ten native species of land-birds survive. The endemic Solitaire was killed off even before the human population started to grow. Forest removal opened new habitats for introduced plants and animals, some of which are now highly invasive pests.Human impact on Rodrigues has gone beyond biotic effects. Cultivation of row-crops on the hilly terrain, and the keeping of domesticated animals in excessive numbers, led to the loss of most of the topsoil by the beginning of the twentieth century. Soil removal and compaction drastically modified the hydrology of the island, and silt deposition in the lagoon has contributed to fish decline. The inherent vulnerability of the native biota, the twin hazards of cyclones and droughts that befall the island, and demographic pressure, have all exacerbated the rate and degree of resource degradation.


1932 ◽  
Vol 7 (1) ◽  
pp. 309-318 ◽  
Author(s):  
E. BERKELEY ◽  
C. BERKELEY

No collection of littoral Polychaeta from the west coast of Vancouver island has hitherto been described. This paper records twenty-eight species collected on that coast at two bays north of Barkley sound. Of these twenty-eight species, twenty-two have already been recorded from the east coast of the island. Of the six remaining species, two have previously been known from California only, one from California and Japan and one from Alaska only; one is a new record for the west coast of North America and one is a new species.


2008 ◽  
Vol 21 (1) ◽  
pp. 22-39 ◽  
Author(s):  
Siegfried D. Schubert ◽  
Yehui Chang ◽  
Max J. Suarez ◽  
Philip J. Pegion

Abstract In this study the authors examine the impact of El Niño–Southern Oscillation (ENSO) on precipitation events over the continental United States using 49 winters (1949/50–1997/98) of daily precipitation observations and NCEP–NCAR reanalyses. The results are compared with those from an ensemble of nine atmospheric general circulation model (AGCM) simulations forced with observed SST for the same time period. Empirical orthogonal functions (EOFs) of the daily precipitation fields together with compositing techniques are used to identify and characterize the weather systems that dominate the winter precipitation variability. The time series of the principal components (PCs) associated with the leading EOFs are analyzed using generalized extreme value (GEV) distributions to quantify the impact of ENSO on the intensity of extreme precipitation events. The six leading EOFs of the observations are associated with major winter storm systems and account for more than 50% of the daily precipitation variability along the West Coast and over much of the eastern part of the country. Two of the leading EOFs (designated GC for Gulf Coast and EC for East Coast) together represent cyclones that develop in the Gulf of Mexico and occasionally move and/or redevelop along the East Coast producing large amounts of precipitation over much of the southern and eastern United States. Three of the leading EOFs represent storms that hit different sections of the West Coast (designated SW for Southwest coast, WC for the central West Coast, and NW for northwest coast), while another represents storms that affect the Midwest (designated by MW). The winter maxima of several of the leading PCs are significantly impacted by ENSO such that extreme GC, EC, and SW storms that occur on average only once every 20 years (20-yr storms) would occur on average in half that time under sustained El Niño conditions. In contrast, under La Niña conditions, 20-yr GC and EC storms would occur on average about once in 30 years, while there is little impact of La Niña on the intensity of the SW storms. The leading EOFs from the model simulations and their connections to ENSO are for the most part quite realistic. The model, in particular, does very well in simulating the impact of ENSO on the intensity of EC and GC storms. The main model discrepancies are the lack of SW storms and an overall underestimate of the daily precipitation variance.


1989 ◽  
Vol 26 (8) ◽  
pp. 1612-1616 ◽  
Author(s):  
T. P. Poulton ◽  
J. D. Aitken

Sinemurian phosphorites in southeastern British Columbia and southwestern Alberta conform with the "West Coast type" phosphorite depositional model. The model indicates that they were deposited on or near the Early Jurassic western cratonic margin, next to a sea or trough from which cold water upwelled. This suggests that the allochthonous terrane Quesnellia lay well offshore in Sinemurian time. The sea separating Quesnellia from North America was partly floored by oceanic crust ("Eastern Terrane") and partly by a thick sequence of rifted, continental terrace wedge rocks comprising the Purcell Supergroup and overlying Paleozoic sequence. This sequence must have been depressed sufficiently that access of upwelling deep currents to the phosphorite depositional area was not impeded.


Zoosymposia ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 147-150
Author(s):  
ROGER R. SEAPY

Taxonomic characterization of pterotracheoid gastropods, morphological characteristics and occurrence in California Current waters are reviewed. Single species of atlantid (Atlanta californiensis) and carinariid (Carinaria japonica) from these waters are described and illustrated.


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