Spatial Ecology of the Threatened Eastern Indigo Snake (Drymarchon couperi) in a Subtropical Coastal Landscape in the Southern Extent of its Range

2017 ◽  
Author(s):  
Matthew Metcalf
Ecography ◽  
2001 ◽  
Vol 24 (5) ◽  
pp. 511-524 ◽  
Author(s):  
Tomas Roslin

2020 ◽  
Vol 651 ◽  
pp. 125-143
Author(s):  
TD Auth ◽  
T Arula ◽  
ED Houde ◽  
RJ Woodland

The bay anchovy Anchoa mitchilli is the most abundant fish in Chesapeake Bay (USA) and is a vital link between plankton and piscivores within the trophic structure of this large estuarine ecosystem. Baywide distributions and abundances of bay anchovy eggs and larvae, and larval growth, were analyzed in a 5 yr program to evaluate temporal and spatial variability based on research surveys in the 1995-1999 spawning seasons. Effects of environmental variability and abundance of zooplankton that serve as prey for larval bay anchovy were analyzed. In the years of these surveys, 97.6% of eggs and 98.8% of larvae occurred in the polyhaline lower bay. Median egg and larval abundances differed more than 10-fold for surveys conducted in the 5 yr and were highest in the lower bay. Within years, median larval abundance (ind. m-2) in the lower bay was generally 1-2 orders of magnitude higher than upper-bay abundance. Salinity, temperature, and dissolved oxygen explained 12% of the spatial and temporal variability in egg abundances and accounted for 27% of the variability in larval abundances. The mean, baywide growth rate for larvae over the 5 yr period was 0.75 ± 0.01 mm d-1, and was best explained by zooplankton concentration and feeding incidence. Among years, mean growth rates ranged from 0.68 (in 1999) to 0.81 (in 1998) mm d-1 and were fastest in the upper bay. We identified environmental factors, especially salinity, that contributed to broadscale variability in egg and larval production.


Author(s):  
Gus Mills ◽  
Margaret Mills

This book demonstrates how cheetahs are adapted to arid savannahs like the southern Kalahari, and makes comparisons with other areas, especially the Serengeti. Topics dealt with are: demography and genetic status; feeding ecology, i.e. methods used for studying diet, diets of different demographic groups, individual diet specializations of females, prey selection, the impact of cheetah predation on prey populations, activity regimes and distances travelled per day, hunting behaviour, foraging success and energetics; interspecific competition; spatial ecology; reproductive success and the mating system; and conservation. The major findings show that cheetahs are well adapted to arid ecosystems and are water independent. Cheetah density in the study area was stable at 0.7/100 km2 and the population was genetically diverse. Important prey were steenbok and springbok for females with cubs, gemsbok, and adult ostrich for coalition males, and steenbok, springhares, and hares for single animals. Cheetahs had a density-dependent regulatory effect on steenbok and springbok populations. Females with large cubs had the highest overall food intake. Cheetahs, especially males, were often active at night, and competition with other large carnivores, both by exploitation and interference, was slight. Although predation on small cubs was severe, cub survival to adolescence was six times higher than in the Serengeti. There was no difference in reproductive success between single and coalition males. The conservation priority for cheetahs should be to maintain protected areas over a spectrum of landscapes to allow ecological processes, of which the cheetah is an integral part, to proceed unhindered.


Herpetologica ◽  
2011 ◽  
Vol 67 (2) ◽  
pp. 135-145 ◽  
Author(s):  
Nicholas G Burgmeier ◽  
Trent M Sutton ◽  
Rod N Williams

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1269
Author(s):  
George Alexandrakis ◽  
Stelios Petrakis ◽  
Nikolaos A. Kampanis

Understanding the processes that govern the transformation of the landscape through time is essential for exploring the evolution of a coastal area. Coastal landscapes are dynamic sites, with their evolution strongly linked with waves and sea level variations. Geomorphological features in the coastal area, such as beachrock formations and dune fields, can function as indicators of the coastal landscape evolution through time. However, our knowledge of the chronological framework of coastal deposits in the Aegean coasts is limited. Optically Stimulated Luminescence dating techniques are deemed to be very promising in direct dating of the coastal sediments, especially when they are linked with archaeological evidence. The dating of the sediments from different sediment core depths, determined by the method of luminosity, allowed us to calculate the rate of sediment deposition over time. More recent coastal evolution and stability were examined from 1945 to 2020 with the use of aerial photographs and satellite images. This paper presents the 6000 ka evolution of a coastal landscape based on geomorphological, archaeological, and radio-chronological data. Based on the results, the early stages of the Ammoudara beach dune field appears to have been formed ~9.0–9.6 ka BP, while the OSL ages from 6 m depth represented the timing of its stabilization (OSL ages ~5–6 ka). This indicates that the dune field appears to already have been formed long before the Bronze Age (5–10 ka BP). It became stabilized with only localized episodes of dune reactivation occurring. In contrast, while high coastal erosion rates were calculated for modern times.


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