Protection Island Research Articles

On the Determinants of Extinction

We have extended the analyses of Pimm et al. on the risks of extinction to include attributes of the environment, as well as species characteristics, as potential determinants of the risk of extinction. We find their earlier conclusion that large-bodied species are at greater risk of extinction at high population sizes is not supported by the data, nor is the contention that more variable populations are at greater risk of extinction. Our analyses suggest that small populations of small-bodied birds on oceanic islands are more vulnerable to extinction than are large populations of large-bodied birds on more protected islands. Moreover, a significant interaction of body size with type of island (channel vs. oceanic island) indicates that body size influences time to extinction differently depending on the type of island. The potentially complex interactions among determinants of extinction suggested by these data and analyses indicate that conservation policies will need to consider the intricate interactions among characteristics of both the species and the environment. Furthermore, our analysis illustrates the inability of current models to account for any more than about 45% of the variance in extinctions of populations from an extensive data set on bird populations from small islands surrounding Britain. Thus, the ability of models to predict the risk of extinction of particular species on particular islands is still very limited. Policy concerning the management of reintroduced species, therefore, should include data from the species and environments in question as well as model predictions of the risk of extinction.

The forest of Vorsø, Denmark: Succession towards a natural, decidous boreal forest influenced by breeding cormorants

The forest on the strictly protected island Vorsø in Horsens Fjord has since 1952 been examined every ten years to discover the number, basal area, wood volume and aboveground biomass of the species. This paper describes the results from 1982 and the development up to that. The dominating species are Fraxinus excelsior, Ulmus glabra and Fagus sylvatica. The two forests, “Vesterskov” (6.09 ha) and “Østerskov” (2.48 ha) respectively, were, in 1982, still immature. Their number of stems per ha were: 756 and 509; basal area: 38 m2 and 45 m2. volume: 544 m3 and 615 m3; biomass 207 t and 268 t. The annual increase 1972–1982 was respectively 8.8 m3/ha and 0.3 m3/ha. The impact of the cormorant (Phalacrocorax carbo sinensis) is especially in “Østerskov” increasing, since the colony here was established in 1976. The succession of the forest is discussed in relation to the disturbance by the cormorants.

Environmental Contaminants, Human Disturbance and Nesting of Double-Crested Cormorants in Northwestern Washington

-Double-crested Cormorants (Phalacrocorax auritus) in extreme northwestern Washington produced few young (0.27/occupied nest) in 1984; the clutch size was generally small and eggs, if laid at all, were laid later than usual. Residues (geometric means, wet weight) of DDE (0.58 and 0.59 ppm) in eggs from Colville Island and Protection Island were lower than from other locations in the Pacific Northwest, while PCBs (2.19 and 1.37 ppm) were similar to those at most locations. Both contaminants in 1984 were below levels associated with reproductive problems. Eggs also contained concentrations of mercury (0.26 and 0.27 ppm) and selenium (0.31 and 0.28 ppm) below levels associated with reproductive problems. The distribution of nesting colonies in the study area changed dramatically since 1984. The cormorants were most likely responding to increased human disturbance in the San Juan Islands, coupled to additional protection and reduced human activity on Protection and Smith Islands. This presumably led to the abandonment of all nesting islands in the San Juans. The nesting population in the study area in 1988 (all on Protection and Smith Islands) was the highest recorded. Received 13 June 1988, Accepted 15 March 1989.

Nesting Season Censuses of Seabirds on Protection Island, Washington

Nesting Season Censuses of Seabirds on Protection Island, Washington

Breeding Biology of the Rhinoceros Auklet in Washington

During 1974 through 1983, we investigated the breeding biology of the Rhinoceros Auklet (Cerorhinca monocerata) at three main colony sites on the coast of Washington: Destruction Island (offshore) and Protection and Smith islands (inland islands of the Strait of Juan de Fuca). Average burrow densities were higher offshore, where the auklets nested on shrub-covered slopes; inland auklets nested on grassy slopes and level areas. Egg-laying patterns varied among years and populations, although initiation dates on all islands were similar. The incubation periods averaged 45 days and ranged from 39 to 52 days. Chicks were brooded, on average, for 3.9 days (range zero to 9 days). On Protection Island, early-hatched young grew more rapidly than chicks hatched at a later date. Chicks on offshore islands were fed a variety of fish, whereas those on inland islands were fed primarily two species. The inland chicks were fed heavier fish loads, reached heavier peak body weights, and were heavier when they fledged than were offshore chicks. Breeding success was higher on the inland colony sites.

Rhinoceros Auklet Burrow Count on Protection Island, Washington

Rhinoceros Auklet Burrow Count on Protection Island, Washington

Ethics in American Business and Government: The Confused Issues

A comparison of American executives with their predecessors of a century ago reveals a heightening of moral awareness and concern. In both business and government, more duties are recognized today than was the case in the nineteenth century. There is also concern for a greater range of values. But this sort of responsibility is dismissed as unimportant by some critics who claim that the managerial class is failing to come to grips with the international and interracial conflicts of our time. It cannot be denied that some world-shaking decisions have been made recklessly. Although it is difficult to identify the "great decisions," some industrialists and some politicians seem to recognize that they have an obligation, and stand ready to negotiate some new policies. The peculiar difficulty of the present crisis is that preindustrial populations, both here and abroad, cannot formulate actionable demands of the kind that corporations and existing agencies of government can satisfy. We should at least consider the alternative of protected preindustrial islands in our automated sea, where unskilled labor might earn a living with self-respect. Such a course of action would put a strain on our boasted pluralism, but could that strain be as great as that which is now involving us in riots and quixotic military adventures?

The Ostracoda in Paleogeography: ABSTRACT

A study of the depth-distribution of recent ostracods in the San Pedro Channel from Long Beach to Avalon Bay, Catalina Island, has revealed a new tool to aid in the solution of paleogeographic and ecologic problems in California stratigraphy. These microscopic crustaceans are very abundant in shallow salt-water lagoons, in mainland continental shelf sediments down to a water depth of 500 feet, and along protected island shores. The samples collected by Alex Clark and Manley L. Natland show by the presence of soft parts that the more abundant species of ostracods were alive on the bottom when dredged. Comparison with the 26 fossil forms recorded by L. W. LeRoy in 1944 reveals eighteen of his species and varieties surviving to Recent time. Total recent forms recognized to date number approximately 22 genera, 52 species, and 7 subspecies. The following geologic formations and Recent ostracod habitats are grouped together to suggest similar environments, as inferred from the occurrence in each of certain characteristic genera and species. End_Page 2087------------------------------ I. Lower San Joaquin Formation (Upper Pliocene) and Salton Sea deposits (Recent?) II. Upper Etchegoin Formation (Pliocene) and Sunset Lagoon (Recent), Salt marshes of Mission Bay (Recent) III. Upper Imperial Formation (Pliocene) and shore waters of the Gulf of California (Recent), mouth of Mission Bay (Recent) IV. Upper Pico Formation (upper Pliocene or Pleistocene), Lower Etchegoin Formation (Pliocene), lower Imperial Formation (Pliocene or Miocene), Upper Wildcat Series (Upper Pliocene) and Pacific Coast, exposed, continental shelf bottom deposits V. Lomita marl (Lower Pleistocene or Upper Pliocene) and Catalina Island lee shore marl (Recent) Slides are presented to show locality map, anatomy, representative species. and occurrences in the Pliocene of the Midway-Sunset oil field, Kern County, California. End_of_Article - Last_Page 2088------------

Management of Deer and Cattle on the Aransas National Wildlife Refuge, Texas

The Aransas National Wildlife Refuge, consisting of 47,325 acres, is located near Austwell on the Black Jack Peninsula. The presence of many deer there has resulted from almost total protection from hunting and some reintroduction during a period of 16 years. Previously there was only a small remnant of the original population. Problems are arising from the presence of cattle, but they have not reached the critical stage of similar dual-use areas of concern on some western ranges. History of Deer Population.-A good many deer occupied this sparsely populated region until about the middle of the nineteenth century. Allen (1894) quotes a Captain Bailey who said that thousands of deer died here from blacktongue in 1857 or 1858. Deer were rare on the peninsula in the early nineties but were quite numerous on Saint Joseph Island, where they are protected by Messrs. Wood and Allyn, who own the island and use it as a cattle and sheep (Allen, 1894). The northern part of Saint Joseph Island lies less than two miles off the southeastern part of the Black Jack Peninsula, separated by the shallow waters of San Antonio Bay. Possibly, as deer were removed from the mainland, others emigrated to the peninsula from the nearby protected islands. Between 1913 and 1928, deer were not plentiful in the area, although by careful hunting one could secure venison at any time. The local residents did not utilize deer to any extent as the meat of domestic cattle and hogs was better. This fact may have been a contributing factor in the survival of deer in the relatively small but brushy areas in this region. In 1919 Leroy G. Denman of the San Antonio Loan and Trust Company took over the management of the ranch on Black Jack Peninsula. He reported few deer and many hunters between 1919 and 1924. In 1924, a seven foot wire fence with locked gates was installed, and every effort was made to keep out hunters. Denman then introduced deer into the area as follows: 1925-1926: Five or six Texas deer, caught by friends of Mr. Denman.