Use Of Coastline Research Articles

Climate change, site formation, and indigenous use of coastlines in Barbuda

This article explores the landscape dynamics at the island of Barbuda in the context of changing climate to understand (1) the environmental setting of indigenous settlements; (2) the impacts of current coastal processes; and (3) the potential threats moving forward toward increasing pressure of climate change. Focusing on the site of Seaview, on the east coast of Barbuda, we use geoarchaeological methods to reconstruct the ancient geomorphological setting, investigate changes post-abandonment, and identify the hazards faced under future sea-level projections. Our study shows that (1) sea level stabilization after the Mid-Holocene allowed the formation of coral reefs, seagrass beds and other benthic ecosystems that allowed for biogenic sediment accumulation and growth of sand dune retention ridges. (2) These environmental characteristics, including rich marine food sources, supported the establishment and flourishing of Seaview starting ca. 160 BC. (3) Occupation ended at some point between AD960 and 1000. This change coincided with a period of increased storminess, higher SSTs, and possible coral reef mortality that affected both food availability and sediment supply. (4) Lack of sediments triggered progressive sand dune erosion that continues today and has left the sand dune ridge past the tipping point of erosion. (5) Looking into a future of rapidly changing climate, sea level rise poses a severe and devastating threat to the land- and seascapes of Barbuda. With the lowland coastal plain at or only slightly above current sea level, a rate of SLR comparable to Mid-Holocene rates, and rapid loss of sand dune ridges and coral reefs as natural barriers, it is just a matter of time before the lowlands become transformed beyond recognition. The results of this analysis can be used to improve long-term management of the heritage resources of Barbudans and shed light on parallel challenges experienced on other tropical coastal locations.

Tracking data and retrospective analyses of diet reveal the consequences of loss of marine subsidies for an obligate scavenger, the Andean condor.

Over the last century, marine mammals have been dramatically reduced in the world's oceans. We examined evidence that this change caused dietary and foraging pattern shifts of the Andean condor (Vultur gryphus) in Patagonia. We hypothesized that, after the decrease in marine mammals and the increase in human use of coastlines, condor diet changed to a more terrestrial diet, which in turn influenced their foraging patterns. We evaluated the diet by means of stable isotope analysis (δ13C, δ15N and δ34S) of current (last decade) and historical (1841-1933) feathers. We further evaluated the movement patterns of 23 condors using satellite tracking of individuals. Condors reduced their use of marine-derived prey in recent compared with historical times from 33 ± 13% to less than 8 ± 3% respectively; however, they still breed close to the coast. The average distance between the coast and nests was 62.5 km, but some nests were located close to the sea (less than 5 km). Therefore, some birds must travel up to 86 km from nesting sites, crossing over the mountain range to find food. The worldwide reduction in marine mammal carcasses, especially whales, may have major consequences on the foraging ecology of scavengers, as well as on the flux of marine inputs within terrestrial ecosystems.

Validation of Geolocation of Measurements of the Clouds and the Earth’s Radiant Energy System (CERES) Scanning Radiometers aboard Three Spacecraft

Abstract The Clouds and the Earth’s Radiant Energy System (CERES) instrument is a scanning radiometer for measuring Earth-emitted and -reflected solar radiation to understand Earth’s energy balance. One CERES instrument was placed into orbit aboard the Tropical Rainfall Measuring Mission (TRMM) in 1997; two were aboard the Terra spacecraft, launched in 1999; and two were aboard the Aqua spacecraft, launched in 2002. These measurements are used together with data from higher-resolution instruments to generate a number of data products. The nominal footprint size of the pixel at Earth’s surface is 16 km in the cross-scan direction and 23 km in the scan direction for the TRMM platform and 36 km in the cross-scan direction and 46 km in the scan direction for the Terra and Aqua platforms. It is required that the location on Earth of each pixel be known to 1–2 km to use the CERES data with the higher-resolution instruments on a pixel basis. A technique has been developed to validate the computed geolocation of the measurements by use of coastlines. Scenes are chosen in which the reflected solar radiation changes abruptly from the land surface to the darker ocean surface and the Earth-emitted radiation changes from the warm land to the cool ocean, or vice versa, so that scenes can be detected both day and night. The computed coastline location is then compared with the World Bank II map. The method has been applied to data from the three spacecraft and shows that the pixel geolocations are accurate to within 10% of the pixel size and that the geolocation is adequate for current scientific investigations.

The Iberian Peninsula – corridor or cul-de-sac? Mammalian faunal change and possible routes of dispersal in the last 2 million years

The Iberian Peninsula is almost surrounded by the sea and is topographically and ecologically variable. These factors will have impacted on both the distribution and dispersal patterns of large mammals (including hominins) within Iberia, and are considered in detail in this paper. There are two routes of mammalian dispersal into Iberia: across the Pyrenees and across the Gibraltar Strait. With an increasing interest in the possible use of coastlines by early hominins the latter route has been the focus of much discussion. However, the arguments are limited by the relative lack of hominin remains and archaeology from the Early Pleistocene. This paper takes a wider perspective to hominin dispersals by examining what is known of the evolution and movements of other taxa in Iberia and how these may inform our understanding of the hominin fossil record. Beginning by briefly reviewing the present day and Pleistocene glacial and interglacial vegetation of Iberia, it then considers the large-mammal fauna. Particular attention is paid to the potential routes of movement for terrestrial animals in and out of the peninsula, and the evidence for each route is assessed. Iberia was a refuge for temperate species during the Quaternary glacial cycles and movements of Quaternary faunas are reviewed in the light of modern phylogeographic analyses and studies of fossil assemblages. Iberian faunas are highly variable, with some absences of otherwise widespread European animals, but cold-phase taxa such as reindeer and woolly rhinoceros did cross the Pyrenees. It seems that the large mountain ranges were less a barrier for the dispersal of these taxa than the line which today forms the limit of the summer drought. Iberia also provided the last refuge for extinct species such as the Neanderthals and endangered extant species such as the Iberian lynx.

Coastlines, Submerged Landscapes, and Human Evolution: The Red Sea Basin and the Farasan Islands

ABSTRACT We examine some long-standing assumptions about the early use of coastlines and marine resources and their contribution to the pattern of early human dispersal, and focus on the southern Red Sea Basin and the proposed southern corridor of movement between Africa and Arabia across the Bab al-Mandab Straits. We reconstruct relative sea levels in light of isostatic and tectonic effects, and evaluate their paleogeographical impact on the distribution of resources and human movement. We conclude that the crossing of the Bab al-Mandab posed little significant or long-lasting physical or climatic barrier to human transit during the Pleistocene and that the emerged continental shelf during periods of low sea level enhanced the possibilities for human settlement and dispersal around the coastlines of the Arabian Peninsula. We emphasize the paleogeographical and paleoenvironmental significance of Pleistocene sea-level change and its relationship with changes in paleoclimate, and identify the exploration of the submerged continental shelf as a high priority for future research. We conclude with a brief description of our strategy for underwater work in the Farasan Islands and our preliminary results.