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At least 667 records · Page 37Linked to original sources
USGS1968

Mortality among bobwhites confined to a heptachlor contaminated environment

The lethal effects of heptachlor on bobwhites ( Colinus virginianus ) were studied at the Patuxent Wildlife Research Center during 1962 and 1963. A pair of adult birds was placed in each of 32 wire-covered field pens (20 x 50 x 61/2 ft) in May, 1962, and in 36 additional pens in May, 1963. Heptachlor (technical grade on clay granules) was spread in the pens at rates of1/8, 1/4, 1 1/4 and 2 lb/acre. In 1963 the treated pens were thoroughly soaked with a hose before birds were introduced to avoid the possibility of birds pecking granules. Heptachlor at 1 1/4 and 2 lb/acre caused severe mortality among birds introduced successively during the first 15 days after application. Mortality declined rapidly among birds placed in these same pens thereafter and was undetectable after 45 days. Mortality at 1/4 lb/acre was significant only during the first 15 days of the 1962 test. There was no detectable difference in mortality of the sexes. Water applied to the pens followed by fairly heavy rain did not significantly affect mortality.

Alabama↗
USGS1980

High duck nesting success in a predator-reduced environment

Duck nesting and production were studied during 1969-74 on a 51-ha field of undisturbed grass-legume cover and a surrounding 8.13-km 2 area in north-central South Dakota. The principal mammalian predators of ducks were reduced within a 259-km 2 zone from May 1969 through August 1971. Dabbling duck nest densities, hatching success, and breeding populations attained high levels. Seven duck species produced 1,062 nests on the 51-ha field during 6 years, 864 (81%) hatched, 146 (14%) were destroyed, and 52 (5%) had other fates. During 1970-72, when predator reduction was most effective, the hatching success for 756 nests was 94%. The number of mallard ( Anas platyrhynchos ) nests increased from 37 (0.7/ha) in 1969 to 181 (3.5/ha) in 1972. Mallard pairs increased from 2.8/km 2 to 16.8/km 2 on the 8.13-km 2 area during the same period. A minimum of 7,250 ducklings hatched on the 51-ha field during the 6 years, including 2,342 ducklings in 1972. Exceptionally high duck nesting densities and hatching rates occurred when predators were controlled.

South Dakota↗
USGS1995

Habitat preferences of wintering shorebirds in a temporally changing environment: Western sandpipers in the San Francisco Bay estuary

We examined habitat preferences of 106 radio-marked Western Sandpipers ( Calidris mauri ) in the San Francisco Bay estuary during winter and spring at two scales: comparing proportions of habitats in their home range with habitats available in the study area (second-order selection), and comparing proportions of radio locations in different habitats with their availability in the home range (third-order selection). Daily and seasonal habitat preferences differed significantly as habitat availability changed temporally. Under second-order selection, Western Sandpipers preferred tidal sloughs and mud flats on winter low tides, and salt-pond levees at high tides. They preferred salt-pond levees and mud flats at low tides, and salt-pond levees at high tides under third-order selection. During the spring, their preferred habitats were drained and tidal salt ponds, and seasonal wetlands at high tide. At low tide, their preferred habitats were tidal sloughs and tidal salt ponds. Salt-marsh plains were the least preferred habitats during both seasons. Adults were more selective than juveniles in use of low tide habitats, but salt-pond levees were the most preferred habitats for both. Habitat preferences varied considerably when different estimates of habitat availability and use were used. If mud-flat habitats were measured as linear foraging areas along the tide line, the preference for those habitats increased from second to first. When second-order selection was estimated from radio locations rather than home ranges, the resulting composition was similar to third-order selection. Our results suggest that regional conservation plans that restore salt marshes for the benefit of endangered species must consider the effects of losing artificial salt-pond habitats, which are locally important for sandpipers.

The Auk↗
USGS2024

Factors affecting the density of Metabetaeus lohena (Decapoda: Alpheidae) at a high-density anchialine pool environment on the Kona Coast of the Island of Hawai‘i

Caridean shrimps (Caridea) are the dominant macroinvertebrates in most anchialine ecosystems. Hawaiian anchialine ecosystems, primarily composed of shallow surface pools connected to the ocean via hypogeal networks of cracks, tubes, and other voids, support 10 caridean shrimp species, including two federally listed as endangered. Little is known about most of these species. The objective of this study was to identify factors that affect the abundance and distribution of Metabetaeus lohena (Alpheidae), an uncommon species found across the Hawaiian Archipelago, at Kaloko-Honokōhau National Historical Park, Island of Hawai‘i. This park supports the highest concentration of anchialine pools in the State of Hawai‘i and is critical to protecting this threatened ecosystem. During 2017, we measured the density of M. lohena during nighttime surveys, as well as a variety of other biological, physical, and chemical parameters, in 130 pools. Metabetaeus lohena occupied 71.5% of the pools surveyed, with a mean density of 7.32 individuals/m 2 (95% CI = 5.14–9.49). Invasive fish and the endemic shrimp Halocaridina rubra (Atyidae) had the strongest effects on M. lohena density, with negative and positive relations, respectively. In the first estimate of M. lohena density at this scale, our data indicate that Kaloko-Honokōhau supports about 11,480 shrimp (95% CI = 8,054–14,906) in the pools surveyed. Furthermore, our models predict that this park could support an additional 1,695 individuals (95% CI = 955–3,008) for a population of about 13,175 shrimp if fish were removed from 19 pools in which M. lohena are absent.

Hawaii↗
USGS1997

Kandia: threatened forest, threatened livelihood - a study of human-environment interaction in the Department of Velingara, Senegal

This case study is one of several carried out as part the Long-term Environmental Monitoring in Senegal Project. Co-financed by USAID and the U.S. Geological Survey's EROS Data Center (EDC), and implemented by EDC and the Centre de Suivi Ecologique (CSE), this project has carried out extensive monitoring of natural resources and land use patterns in Senegal in order to better understand the complex dynamics of change in semi-arid tropics. The monitoring, as carried out by EROS staff and their Senegalese collaborators, has involved use of information collected by remote sensing (satellite and aerial photographs) as well as extensive field work including the collection of physical information about soils, vegetation, land use practices, and biodiversity at 2 over 600 sites in all parts of the country (Tappan and Wood, 1995). This information provides a remarkable record of changes in physical and land cover parameters over the last 30 years. Figure 2 presents a satellite image of the eastern Kolda Region covering the Department of Velingara.

Report↗