Search results for "gull"
showing 10 items of 63 documents
Changes in the Breeding Bird Fauna, Waterbird Populations in Particular, on Lake Engure (Latvia) over the Last 50 Years
2005
The nesting bird fauna (186 species) of Lake Engure and its surroundings has changed considerably over the last 50 years: 18 species have appeared as newcomers (among them 56% of southern, 6% of northern origin), 10 species have ceased nesting (among them 60% of northern, 10% of southern origin). These changes might be explained by global warming. Dramatic changes recorded in all waders can be accounted for by the local habitat loss and a general decline in wider geographic ranges. The Black-headed Gull (Larus ridibundus) population increased from 200 pairs in 1940s to 34,000 pairs in 1986, and then declined to 4,200 pairs in 2002. Nesting duck (all species combined) numbers and their nesti…
A possible evolutionary model of “aligned pockmarks”
2014
Conversando con Rafael Argullol
2014
Sin resumen.
Morphological characteristics of ephemeral gullies in Sicily, south Italy
2011
Ephemeral gullies (EGs) are channels of different sizes refilled by tillage equipment normally used on farms. In this paper, the data-set collected from 1995 to 2007 in a wheat-cultivated area in Raddusa (Sicily, Italy), having a surface of almost 80 ha, were used to analyze the morphological characteristics of EGs. The measurements show an high temporal variability in EG characteristics. The EG measurements and the rill erosion measurements carried out in 15 plots located in the experimental “Sparacia” area (Sicily), demonstrated that a morphological similarity condition exists between rills and ephemeral gullies. The occurrence of step-pool structures in an EG occurring in the observation…
Gully erosion in a small experimental catchment in SW Spain
2014
Testing the use of an image-based technique to measure gully erosion at Sparacia experimental area
2017
The first part of this investigation was aimed at testing the use of a three‐dimensional (3D) digital terrain model and a quasi‐tridimensional (2.5D) digital elevation model obtained by a large series of oblique images of eroded channels taken from consumer un‐calibrated and non‐metric cameras. For two closed earth channels having a different sinuosity, the ground measurement of some cross sections by a profilometer (P) was carried out and their real volume was also measured. The comparison among the three methods (3D, 2.5D, and P) pointed out that a limited underestimation of the total volume always occurs and that the 3D method is characterized by the minimum difference between measured a…