Effects of the Alqueva Dam Reservoir on the Distribution of Steppe Birds

Effects of a Large Irrigation Reservoir on Aquatic and Riparian Plants: A History of Survival and Loss

“…In agreement with these results, studies on another biota such as birds, and dragonflies after the Alqueva Dam implementation also detected changes in abundances and composition but did not find a variation in richness totals [28,29]. In fact, changes in aquatic and riparian vegetation largely affect bird community composition in the Guadiana River, as well as many other organisms in this area [28,59]. For instance, bat populations were affected by the disappearance of around 200 km of riparian habitats of the 'old' Guadiana river, by the homogeneous habitat created by the flooded areas that can only be used for foraging in the remaining island habitats [60].…”

“…However, these large landscape changes and fragmentation likely appear to be responsible for changes in community composition and abundances [1,50]. In agreement with these results, studies on another biota such as birds, and dragonflies after the Alqueva Dam implementation also detected changes in abundances and composition but did not find a variation in richness totals [28,29]. In fact, changes in aquatic and riparian vegetation largely affect bird community composition in the Guadiana River, as well as many other organisms in this area [28,59].…”

Kernel Density Estimation of Tropical Cyclone Frequencies in the North Atlantic Basin

“…All of the centrographic statistics (mean center, median center, and minimum distance) were concentrated in the same general area for each decade (Figure 3), thus increasing our confidence in analyzing the decadal centroid patterns of tropical cyclone tracks. Of the three measures of centrography, the mean center statistic was selected because it calculates the mean distribution, or central tendency, of all X and Y tropical cyclone coordinates occurring in each decade and is the most widely used centrographic statistic [30,35,44]. A temporal analysis of decadal mean centers (centroids) of tropical cyclones since the 1940s reveals a trend toward the east until the 1980s, when the pattern shifted back toward a more westward and southward displacement (Figure 4).…”

“…CrimeStat III was also used to compute the centrographic statistics, including mean center [30,35], median center [36,37], minimum distance [38,39], and standard deviational ellipse [31,40], for each decade from 1944-2009. The mean center is the simplest descriptor of distribution and describes the mean of the X and Y coordinates [41].…”