Thomas E. Lacher

Environmental Degradation in the Pantanal EcosystemIn Brazil, the world's largest wetland is being threatened by human activities

ment was part of the opening ceremonies of a worldwide campaign directed at the conservation of wetlands. The campaign was promoted by UNESCO, with the cooperation of the International Union for the Conservation of Nature and Natural Resources (IUCN) and the World Wildlife Fund (WWF). The Pantanal, with its extraordinary diversity and abundance of wildlife, is a threatened region. Deforestation; expanding agriculture; illegal hunting and fishing; and pollution of the water with herbicides, pesticides, and by-products of fuel alcohol production have caused a progressive deterioration of the natural environment, placing at risk one of Brazils most important ecosystems.

The Brazilian Caatinga in South American zoogeography: tropical mammals in a dry region

Recent research in South American biogeography on groups other than mammals suggests that the semi-arid Caatinga of northeastern Brazil provided xeric refugia during mesic phases of the Pleistocene climatic cycles. If this supposition is correct, the Caatinga mammal fauna might be expected to contain numerous species showing a pronounced level of adaptation to aridity and the origins of a substantial segment of the fauna sthould be traceable to the diversification and eventual speciation that would be expected to have resulted from extended isolation in a xeric environment. An analysis of the extant mammal fauna fails to corroborate these predictions; only one endemic mammal species is found in the Caatinga, and the fauna lacks the expected physiological and morphological adaptations. Other vertebrate groups also exhibit low levels of endemism. The high degree of climatic unpredictability that is characteristic of the Caatinga may preclude the development of a unique fauna adapted to xeric conditions. It appears that the present inhabitants of the region avoid the environmental effects of aridity and climatic unpredictability during harsh periods by utilizing the numerous mesic enclaves scattered throughout the North- east. Indeed, even during periods of elevated precipitation, most mammal species reach their highest density in these relatively restricted areas. Although the Caatinga contains a xeric-adapted flora, it harbours an anomalous mammal fauna that is more characteristic of a mesic tropical biome in terms of both species composition and overall adaptation. The development of an assemblage of verte- brates whose adaptations do not parallel those of the dominant flora in a region is an unusual situation which should be of particular interest to palaeontologists attempting to reconstruct ancient environments.

FOOD PREFERENCE AS A FUNCTION OF RESOURCE ABUNDANCE WITH MULTIPLE PREY TYPES: AN EXPERIMENTAL ANALYSIS OF OPTIMAL FORAGING THEORY

Data were collected on the response of a small population of folivores (Kerodon rupestris: Caviidae) to changes in the absolute abundance of 10 different species of leaves. When absolute abundances were tripled (relative abundances were held constant) the folivore population significantly altered its proportional consumption of food types. In general, preferred foods were consumed in greater relative proportions when abundance was increased and the relative utilization of less preferred foods declined. Otherwise, our results were problematic in relation to the assumptions and predictions of the energy maximization model of optimal foraging theory. First, not all foods of low rank decreased in consumption when we increased the abundance of high-ranked foods. The partial consumption of low-ranked foods (or partial preferences as referred to in the literature) is contrary to the tenets of energy maximization. Second, preferences did not remain consistent from phase to phase. In fact, ranks shifted considerably, especially with respect to high-ranked foods. A number of factors may have been responsible for these contradictions to optimal foraging theory. Folivores may represent an example of the special case of optimal foraging with nutrient constraints (Pulliam 1980). The partial consumption of low-ranked foods would then be expected in this situation. Also, the encounter rate for a given item or type is probably not constant in time or space; the rate of encounter is an ephemeral value, affected by an animals degree of satiation, and dependent upon its degree of familiarity with the distribution of food items within its foraging area. This suggests that animals are optimal foragers, sensu Charnov, only in the short term. The probability of accepting an item when it is encountered will be either zero or one in the short term, but in the long term (hours, days, seasons, years) it will assume an average value between zero and one. Finally, consumers should evolve search images for types or species, when within-type variability is very small and overlap among types minimal. When within-type variability is large, and distributions of food value overlap a great deal, natural selection should favor consumers that select high value items and do not generalize on a types average values. We present a scenario which proposes that feeding habits may influence the way a consumer optimizes its foraging behavior. Empirical tests of optimal foraging models based upon energy maximization have upheld theoretical predictions when predators were presented with limited prey choices (e.g., Goss-Custard 1977; Krebs et al. 1977). Tests which have examined more complex situations (Zach and Smith 1980; this paper) suggest that models which include considerations of nutrient constraints (Pulliam 1975) or predator learning (Hughes 1979; Stenseth and Hansson 1979; Pulliam 1980) may, in fact, be more appropriate.

Availability of Resources and Use of Space in Eastern Chipmunks, Tamias striatus

The adaptive significance of the use of resources is a central issue in population ecology. Empirical and theoretical studies have examined the relationship between mean size of home range and environmental variables. Few studies have examined age, gender, and individual variation in these relationships. We examined the relation between patterns of variation in size of home range in eastern chipmunks, Tamias striatus , and distribution and abundance of resources in northwestern Pennsylvania. Previous research on Tamias showed that mean size of home range responded quickly to changes in abundance of resources, suggesting that individual variation in size of home range would be tied to resources. We captured 278 individuals 3,933 times. Forty individuals were studied in 1981 and 49 in 1982. Home ranges were calculated and all mast-producing trees were mapped yielding expected abundance of resources for all home ranges. Abundance of resources was an increasing function of size of home range even when corrected for competition for access to resources, contrary to predictions based upon models of use of space. When examined by age and sex of chipmunks and by different species of mast-producing trees, we noted that the distribution and abundance of white oaks influenced the distribution of age and sex groups on the study area and appeared to be a disputed resource for adults. Studies of patterns of age, sex, and individual variation in complex behaviors are logistically challenging, but they are the best way to empirically test models in population ecology dealing with the adaptive significance of access to space and resources.

Mamíferos da Fazenda Nhumirim, sub-região de Nhecolândia, Pantanal do Mato Grosso do Sul: I - levantamento preliminar de espécies

The pantanal is one of the worlds richest freshwater wetlands. The pantanal is located in the flood plain of the headwaters of the Paraguai river, covering 140,000km2. The habitats of the Pantanal are present in a complex mosaic. The major habitat types are: pockets of forests, called capao or cordilheira, seasonally flooded grasslands or campos, and permanent or temporary lagoons, called baias. The Pantanal harbors both rich and abundant mammal fauna. A survey was conducted at Fazenda Nhumirim, a research station run by the Centro de Pesquisa Agropecuaria do Pantanal (CPAP) in Corumba, a research branch of EMBRAPA. The Fazenda covers an area of 4,310 ha in the sub-region of Nhecolândia, appoximately 150km east of Corumba, Mato Grosso do Sul. The area receives an average annual rainfall of 1,022mm, and has a mean monthly temperature that varies between 29.1oC (January) and 22.0oC (June). Four routes were followed between two times during ten days of each month. The survey routes were covered on horseback by between two and four observers. Each route was followed and equal number of times in the morning and in the afternoon, to eliminate bias related to the activity patterns of mammals. In order to evaluate relative abundance of nocturnal species, we also conducted a number of nocturnal censuses. These censuses were done by car; a high intensity searchlight was used to spot the animals. We also conducted a trap-mark-recapture survey of the small mammals at Fazenda Nhumirim. After the census period, we continued to collect observations on the occurrence of mammals at the Fazenda, noting wherever possible the kind of habitat in which the animals were observed. The survey identified a diversity of mammals at Fazenda Nhumirim: six orders, 14 families, 19 genera, and 20 species. Nasua nasua was the most frequently observed species during the diurnal census, accounting for 61.5 percent of all observations. Dusicyon (formely Cerdocyon) thous was the most frequently observed species on the nocturnal census (39.13%). The small mammal community of Fazenda Nhumirim is composed of seven species: one marsupial, four cricetine rodents and two echimyid rodents.

Parrot conservation in the lesser antilles with some comparison to the Puerto Rican efforts

There are four endemic species of Amazona parrots in the Lesser Antilles, namely the imperial or Sisserou parrot Amazona imperialis and the red-necked or Jaco parrot A. arausiaca of the Commonwealth of Dominica, the St Lucia parrot A. versicolor of St Lucia, and the St Vincent parrot A. guildingii of St Vincent and The Grenadines. Seven other endemic members of the same family, Psittacidae, have become extinct in the region in historical times. These four extant species are now all threatened by deforestation, predation, illegal hunting and collecting, and natural disasters. Measures for parrot conservation consist of environmental education, habitat protection, enforcement of appropriate legislation, and enhancement of wild breeding and captive breeding. These approaches are reviewed for each of the islands and compared with the relatively successful but much more expensive conservation measures adopted for the Puerto Rican parrot A. vittata in the Commonwealth of Puerto Rico. Recommendations are made for future conservation emphasis and research.

Ethical Obligations of Multinational Corporations to the Global Environment: The McDonald’s Corporation and Conservation

The Greek word oikos, or house, is the root of the English words ecology and economy. It is thus ironic that economic development for many years has been viewed as being incompatible with ecological well-being. The world economy has become increasingly more interconnected during the past several decades with the formation of regional and international trading blocks and economic communities. At the same time, we have become more cognizant of the global nature of large-scale environmental change. The connections between global economic activity and global environmental conditions are well defined. In a sense we have come full circle back to the Greek root of a common space, our house.