High Human Population Density Research Articles

Paleolimnological investigations of anthropogenic environmental change in Lake Tanganyika: IX. Summary of paleorecords of environmental change and catchment deforestation at Lake Tanganyika and impacts on the Lake Tanganyika ecosystem

Paleorecords from multiple indicators of environmental change provide evidence for the interactions between climate, human alteration of watersheds and lake ecosystem processes at Lake Tanganyika, Africa, a lake renowned for its extraordinary biodiversity, endemism and fisheries. This paper synthesizes geochronology, sedimentology, paleoecology, geochemistry and hydrology studies comparing the history of deltaic deposits from watersheds of various sizes and deforestation disturbance levels along the eastern coast of the lake in Tanzania and Burundi. Intersite differences are related to climate change, differences in the histories of forested vs. deforested watersheds, differences related to regional patterns of deforestation, and differences related to interactions of deforestation and climate effects. Climate change is linked to variations in sediment accumulation rates, charcoal accumulation, lake level and water chemistry, especially during the arid-humid fluctuations of the latter part of the Little Ice Age. Differences between forested and deforested watersheds are manifested by major increases in sediment accumulation rates in the latter (outside the range of climatically driven variability and for the last ∼40 years unprecedented in comparison with other records from the lake in the late Holocene), differences in eroded sediment and watershed stream composition, and compositional or diversity trends in lake faunal communities related to sediment inundation. Variability in regional patterns of deforestation is illustrated by the timing of transitions from numerous sedimentologic, paleoecologic and geochemical indicators. These data suggest that extensive watershed deforestation occurred as early as the late-18th to the early-19th centuries in the northern part of the Lake Tanganyika catchment, in the late-19th to early-20th centuries in the northern parts of modern-day Tanzania, and in the mid-20th century in central Tanzania. Rapid increases in sediment and charcoal accumulation rates, palynological and lake faunal changes occurred in the early-1960s. We interpret this to be the result of greatly enhanced flushing of sediments in previously deforested watersheds triggered by extraordinary rainfall in 1961/62. Regional differences in deforestation histories can be understood in light of the very different cultural and demographic histories of the northern and central parts of the lake shoreline. Incursion of slaving and ivory caravans from the Indian Ocean to the central coast of Lake Tanganyika by the early-19th century, with their attendant diseases, reduced human and elephant populations and therefore maintained forest cover in this region through the late-19th to early-20th centuries. In contrast, the northeastern portion of the lakeshore did not experience the effects of the caravan trades and consequently experienced high human population densities and widespread deforestation much earlier. These studies demonstrate the importance of paleolimnological data for making informed risk assessments of the potential effects of watershed deforestation on long-term lake ecosystem response in the Lake Tanganyika catchment. Differences in sediment yield and lake floor distribution of that yield, linked to factors such as watershed size, slope, and sediment retention, must be accounted for in management plans for both human occupation of currently forested watersheds and the development of future underwater reserves.

People, energy and avian species richness

ABSTRACTAim To investigate the inter‐relationships between energy availability, species richness and human population density, particularly whether human population density influences the manner in which species richness responds to energy availability.Location British 10‐km grid cells.Methods Using regressions, we investigate how human population density varies with energy availability and the nature of relationships between the numbers of species, classified by abundance and threat categories, and human population density. We then assess whether the relationships between these species richness measures and energy availability are altered when accounting for human population density. We conduct analyses using both independent error models and ones that control for spatial autocorrelation.Results Human population density was strongly and positively correlated with energy availability. Total species richness, and that of unthreatened, threatened, common and moderately common species, increases in a positive decelerating manner with human density. When human population density was taken into account, these species groups exhibited similar species–energy relationships, but the slopes of these relationships were significantly reduced in independent error models and, in the case of total richness, in spatial models.Main conclusions Positive correlations between human density and species richness probably arise as both increase with energy availability. Our data are compatible with the suggestion that high human population densities reduce the rate at which species richness increases with energy availability, but additional research is required before causality can be confirmed.

Environmental and Human Demographic Features Associated with Epizootic Raccoon Rabies in Maryland, Pennsylvania, and Virginia

We assessed land use and demographic data as predictors discriminating between counties experiencing large or small first epizootics of rabies among raccoons (Procyon lotor). Monthly county reports of raccoons testing positive for rabies were obtained from rabies surveillance databases from Maryland, Pennsylvania, and Virginia (USA). Environmental and demographic data for the three states were obtained from public sources. On the basis of total reports of raccoon rabies during the first defined epizootic period, the 203 counties were dichotomized at the 75th percentile as having a large epizootic (> or = 24 rabid raccoons in the first epizootic) (51 counties) or a small epizootic or no epizootic (152 counties). A high percentage of agricultural land use [OR = 9.1, 95% CI (3.6-23.1)], high water coverage in combination with low human population density [OR = 8.8, 95% CI (2.9-27.0)], and low water coverage with high human population density [OR = 11.7, 95% CI (4.0-34.1)] were positively associated with large rabies epizootics. Counties with more than 15% of mixed forest were less likely to experience large epizootics than were counties with < or = 15% of mixed forest [OR = 0.3, 95% CI (0.1, 0.9)]. A combination of land use and human population density measures provided the best model for determining epizootic size and may be important predictors of epizootic behavior and risk of exposure to this reservoir species.

ENERGY, SPECIES RICHNESS, AND HUMAN POPULATION SIZE: CONSERVATION IMPLICATIONS AT A NATIONAL SCALE

The maintenance of biodiversity rests on understanding and resolving conflict between patterns of species occurrence and human activity. Recent debate has centered on the relationship between species richness and human population density. However, conclusions have been limited by the lack of investigations of these relationships for individual countries, at which level most practical conservation actions are determined, and for a spatial resolution at which practical conservation planning takes place. Here, we report the results of the first such analysis, for birds in South Africa. Species richness and human density are positively correlated, apparently because both respond positively to increasing levels of primary productivity. High species richness is maintained by currently designated reserves, but the areas surrounding these have higher human population densities than expected by chance, placing the reserves under increasing external pressure. Not all species lie within protected areas, but the options are limited for building on the present network to generate a more comprehensive one, which protects all species and significantly reduces the conflict with human activities by designating new reserves in areas with lower human populations. Ultimately, the only solution to the conflict between biodiversity and people is likely to be individual‐based regulation of human population size.

Influenza pandemic planning

Periodically, novel influenza viruses emerge and spread rapidly through susceptible populations, resulting in worldwide epidemics or pandemics. Three pandemics occurred in the 20th century. The first and most devastating of these, the “Spanish Flu” (A/H1N1) pandemic of 1918–1919, is estimated to have resulted in 20–50 million or more deaths worldwide, with unusually high mortality among young adults [C.W. Potter, Chronicle of influenza pandemics, in: K.G. Nicholson, R.G. Webster, A.J. Hay (Eds.), Textbook of Influenza, Blackwell Science, Oxford, 1998, p. 3]. Mortality associated with the 1957 “Asian Flu” (A/H2N2) and the 1968 “Hong Kong Flu” (A/H3N2) pandemics was less severe, with the highest excess mortality in the elderly and persons with chronic diseases [J. Infect. Dis. 178 (1998) 53]. However, considerable morbidity, social disruption and economic loss occurred during both of these pandemics [J. Infect. Dis. 176 (Suppl. 1) (1997) S4]. It is reasonable to assume that future influenza pandemics will occur, given historical evidence and current understanding of the biology, ecology, and epidemiology of influenza. Influenza viruses are impossible to eradicate, as there is a large reservoir of all subtypes of influenza A viruses in wild aquatic birds. In agricultural-based communities with high human population density such as are found in China, conditions exist for the emergence and spread of pandemic viruses. It is also impossible to predict when the next pandemic will occur. Moreover, the severity of illness is also unpredictable, so contingency plans must be put in place now during the inter-pandemic period. These plans must be flexible enough to respond to different levels of disease.

Fire history of oak–pine forests in the Lower Boston Mountains, Arkansas, USA

Perspective on present day issues associated with wildland fire can be gained by studying the long-term interactions among humans, landscape, and fire. Fire frequency and extent over the last 320 years document these interactions north of the Arkansas River on the southern edge of the Lower Boston Mountains. Dendrochronological methods were used to construct three fire chronologies from 309 dated fire scars that were identified on 45 shortleaf pine ( Pinus echinata) remnants. Fire frequency increased with human population density from a depopulated period (the late 1600s and early 1700s) to a peak in fire frequency circa 1880. Fire frequency then decreased as human population continued to increase. Fire frequency and human population density were positively correlated during an early period (1680–1880) with low levels of population, but negatively correlated during a later period (1881–1910) with high levels of population. We hypothesized that this difference is due to limits on fire propagation and ignition caused by land use and culture, as well as human population density. Relatively high human population densities (>5 humans/km 2) were associated with a peak in the maximum number of fires per decade in this highly dissected, ‘bluff and bench’ landscape compared to less dissected regions of the Ozarks.

The late Quaternary extinction and future resurrection of birds on Pacific islands

People have lived on tropical Pacific islands over the past 30,000 years (Bismarcks, Solomons) or 3000 to 1000 years (the rest of Oceania). Their activities have led to the loss of many thousands of populations and as many as 2000 species of birds that probably otherwise would exist today. This extinction event is documented by avian fossils from archaeological (cultural) and paleontological (noncultural) sites from nearly 70 islands in 19 island groups. Extinction of birds in Oceania rivals the late Pleistocene loss of large mammals in North America as the best substantiated rapid extinction episode in the vertebrate fossil record. Some avian extinctions in Oceania occurred within a century or less after human arrival, while others required millennia or even tens of millennia. Any of these time frames is rapid in an evolutionary or geochronological sense. Inter-island differences in the speed and extent of extinction can be explained by variation in abiotic (A), biotic (B), and cultural (C) factors. Levels of extinction on large, near islands can be comparable to those on small, remote islands when C factors (such as high human population density and introduction of invasive plants and animals) override A factors (such as large land area or little isolation) or B factors (such as rich indigenous floras and faunas). An innovative, proactive conservation strategy is needed not only to prevent further extinctions of birds in Oceania, but also to restart evolution of some of the lineages that have suffered the most loss, such as flightless rails. This strategy should focus on islands with ABC traits that retard rather than enhance extinction.

Trap crops of Striga hermonthica: in vitro identification and effectiveness in situ

The parasitic weed Striga hermonthica is a major yield-reducing factor for cereal crops in savannah regions in Africa. This applies in particular to agro-ecosystems where a high human population density imposes a strong pressure on arable land. In these areas rotation with a leguminous trap crop is an attractive control method. Effectiveness of root exudates from varieties of cowpea (Vigna unguiculata), groundnut (Arachis hypogea) and soybean (Glycine max), on germination of S. hermonthica seeds were assessed in vitro. In addition, a 2-year study on effectiveness in situ was conducted with cowpea variety IT 90k-56 identified in vitro as a potential trap crop. Furthermore, cowpea variety TVX 1850-01F also identified in vitro as a potential trap crop, was tested on-farm. Results indicated that effectiveness of root exudates depends on Striga seed population and it is recommended that geographical origin and host crop of S. hermonthica, period of the year, as well as age of seeds be taken into consideration for identification of potential trap crops. There was no significant difference in Striga infestation of maize in 1995 if sowing of cowpea variety IT 90k-56 had been carried out on June 3 (early sowing), June 20 (intermediate sowing) or July 5 (late sowing) in 1994. However, plots where maize was grown in 1995 after they had been maintained as weed-free-fallow in 1994 showed significantly higher Striga infestation than plots where during previous year early sowing of trap crop had been undertaken. Maize grain yields in 1995 were significantly higher after trap cropping in 1994, regardless of sowing date, compared to weed free fallow plots. On-farm evaluation of cowpea variety TVX 1850-01F showed good results, reducing incidence of S. hermonthica on maize to nearly undetectable level after one season rotation.

Melanic frequencies in three species of moths in post industrial Britain

Changing patterns of morph frequency in three moth species (Biston betularia, Odontoptera bidentata and Apocheima pilosaria) have been investigated using data from the Rothamsted Insect Survey. All three exhibited industrial melanism during the period of high atmospheric pollution in Britain. Three historical and habitat types are compared, the old industrial north of England, rural Scotland, Wales and South-West England, and a southern English intermediate region of high human population density but generally low industrialization. Between 1974 and 1999 the carbonaria morph of B. betularia declined in frequency in the industrial region and is nearly absent from rural areas. It is the form which most closely tracks atmospheric change. It is shown that the insularia forms of B. betularia and the melanic morphs in the other two species have decreased in the industrial region, commencing later than carbonaria, but have maintained their presence and possibly reached equilibrium elsewhere. They may be non-industrial polymorphisms. B. betularia is rarer than the other species and all three species are at lower densities in industrial than in non-industrial regions.

Occurrence of Cryptosporidium sp. oocysts in fecal and water samples in Austria

Oocysts of Cryptosporidium spp. were detected and differentiated by a modular arranged gene amplification procedure in various samples, mostly human stool, feces of herpetotaxa, and water, in different locations of South and Eastern Austria. Cryptosporidium parvum was found in stool samples of immunocompromised persons, in reptile feces, and in water samples. The presence of Cryptosporidium in an area is probably associated with high human population densities since water from protected sources in sparsely inhabited areas is rarely contaminated.

Intensive Cultivation and Environment Use among the Matengo in Tanzania

This study focuses on the agro-ecological background of an intensive cultivation system called ngolo, which has been practiced for over 100 years among the Matengo people in southern Tanzania. The ngolo system is highly sustainable, as it both conserves soil and water and matures the soil; moreover, the high productivity of this system allows for a steady food supply to the Matengo. The other cropping systems in Matengo agriculture, which are closely related to ngolo, economically support farmers. For example, coffee cultivation provides cash to support the local economy, and it also enables farmers to purchase chemical fertilizers. These fertilizers are applied to ngolo fields in the highlands, where fields cannot be left fallow because of high human population densities. Immigrants from the highlands to the woodlands practice a normal ridge system of cultivation called mitumbila, and a slash-and-burn cultivation called matema/malala. These systems are the initial stages in the process of creating suitable soil conditions for ngolo cultivation, and they are major sources of income in new villages where coffee trees are too young to be harvested. Emigrants have succeeded in maintaining ngolo cultivation, even in underpopulated villages, although the cultivation system was originally conceived and sustained under conditions of high population pressure. The system is able to conserve land in new villages that experience similar natural conditions, such as hilly landscapes and intense rainfall. However, social constraints and agricultural effects are not the only reasons why the Matengo have successively used ngolo; they have trusted in ngolo cultivation based on past experience, and it might therefore be a foundation of their culture.

Mollusk Habitats and Fisheries in Kiribati: An Assessment from the Gilbert Islands

Biological and ecological attributes of 24 species of edible bivalves and gastropods from the Gilbert Islands Group, Kiribati, Micronesia, were assessed for their resilience by examining size at maturity, intertidal burying, adjacent subtidal populations, benthic mobility, and larval type. Foraging for mollusks is largely con®ned to the intertidal and shallow subtidal regions, although modern diving gear and outboard motors now provide human foragers access to offshore resources. Changes brought about by human demographic pressures have resulted in overexploitation of a number of molluscan resources. It is suggested that the sustainable use of invertebrates and other marine species for food and nonfood purposes in Kiribati rests on a remodeled form of marine tenure. Atolls present a variety of marine environments and molluscan resources that have provided subsistence living to generations of Paci®c islanders (Tebano et al. 1993, Taniera 1994). Kiribati (Figure 1) is but one of more than 20 nations in the Paci®c, each of which possessed a rich inshore ®sheries tradition and lore. In recent years, however, traditional ecological knowledge (TEK) has suffered the inevitable decline that characterizes similar bodies of knowledge throughout most of Oceania. High human population density, urban drift, more ef®cient extractive technologies, and expanding market opportunities all have inevitably affected the ocean resources of these islands. In this study, I examined the prey biology and ecology of mollusk ®sheries in Kiribati, Gilbert Islands, looking at factors distinguishing vulnerable from resilient resources, and their effect on subsistence. Can traditional ecological knowledge be wedded with modern technology to revive the ®sheries? Because the thrust of this paper is limited to prey biology and ecology in the context of mollusk ®sheries, details of analytic methodology related to foraging ef®ciency are not discussed here, but can be found in Thomas (1999). Data on molluscan resources of the Gilbert Islands date back to the 1950s when Banner and Randall (1952) described the invertebrates of Onotoa Atoll, but identi®cations were poor and there were few detailed descriptions of exploitive strategies. A major interdisciplinary environmental survey on the main atoll of Tarawa, Republic of Kiribati (Abbott and Garcia 1995), expanded species identi®cation and habitat description, and provided an assessment of the impact of human activities (Figure 2). The Tarawa Lagoon Project of 1992±1994 (Paulay 1995) is a major study of the lagoon, and data from that project are included in this study. materials and methods Several communities engaged in subsistence and commercial exploitation of mollusks were investigated intermittently between 1993 and 1998. Research focused on four atolls in the central Gilberts: Abaiang, Tarawa (both urbanized and rural sectors), Maiana, and Abe77 1 Financial support from the University of Hawai`i's Arts and Sciences Advisory Council; funds provided by Alison Kay through a University of Hawai`i Foundation Grant and Research Assistantship; Sigma Xi (The Scienti®c Research Society) Grant-in-Aid of Research nos. 2710 and 8326; the Hawaiian Malacological Society; two grants from Conchologists of America, Inc.; and travel funds provided by Temakei Tebano at the University of the South Paci®c. Manuscript accepted 1 February 2000. 2 Ogden Environmental and Energy Services, 680 Iwilei Road, Suite 660, Honolulu, Hawai`i 96817. Paci®c Science (2001), vol. 55, no. 1:77±97 : 2001 by University of Hawai`i Press

Elimination of rabies from red foxes in eastern Ontario.

The province of Ontario (Canada) reported more laboratory confirmed rabid animals than any other state or province in Canada or the USA from 1958-91, with the exception of 1960-62. More than 95% of those cases occurred in the southern 10% of Ontario (approximately 100,000 km2), the region with the highest human population density and greatest agricultural activity. Rabies posed an expensive threat to human health and significant costs to the agricultural economy. The rabies variant originated in arctic foxes: the main vector in southern Ontario was the red fox (Vulpes vulpes), with lesser involvement of the striped skunk (Mephitis mephitis). The Ontario Ministry of Natural Resources began a 5 yr experiment in 1989 to eliminate terrestrial rabies from a approximately 30,000 km2 study area in the eastern end of southern Ontario. Baits containing oral rabies vaccine were dropped annually in the study area at a density of 20 baits/km2 from 1989-95. That continued 2 yr beyond the original 5 yr plan. The experiment was successful in eliminating the arctic fox variant of rabies from the whole area. In the 1980's, an average of 235 rabid foxes per year were reported in the study area. None have been reported since 1993. Cases of fox rabies in other species also disappeared. In 1995, the last bovine and companion animal cases were reported and in 1996 the last rabid skunk occurred. Only bat variants of rabies were present until 1999, when the raccoon variant entered from New York (USA). The success of this experiment led to an expansion of the program to all of southern Ontario in 1994. Persistence of terrestrial rabies, and ease of elimination, appeared to vary geographically, and probably over time. Ecological factors which enhance or reduce the long term survival of rabies in wild foxes are poorly understood.

Estuaries of the South Atlantic Coast of North America: Their Geographical Signatures

Estuaries of the southeastern Atlantic coastal plain are dominated by shallow meso-tidal bar-built systems interspersed with shallow sounds and both low flow coastal plain and high flow piedmont riverine systems. Three general geographical areas can be discriminated: the sounds of North Carolina; the alternating series of riverine and ocean dominated bar-built systems of South Carolina, Georgia, and northeast Florida, and the subtropical bar-built estuaries of the Florida southeast coast. The regional climate ranges from temperate to subtropical with sea level rise and hurri- canes having a major impact on the region's estuaries because of its low and relatively flat geomorphology. Primary production is highest in the central region. Seagrasses are common in the northern and southern most systems, while intertidal salt marshes composed of Spartina alterniflora reach their greatest extent and productivity in South Carolina and Georgia. Nuisance blooms (cyanobacteria, dinoflagellates, and cryptomonads) occur more frequently in the northern and extreme southern parts of the region. Fishery catches are highest in the North Carolina and Florida areas. Human population growth with its associated urbanization reaches a maximum in Florida and it is thought that the long-term sustainability of the Florida coast for human habitation will be lost within the next 25 years. Tidal flushing appears to play an important role in mitigating anthropogenic inputs in systems of moderate to high tidal range, i.e., the South Carolina and Georgia coasts. The most pressing environmental problems for the estuaries of the southeastern Atlantic coast seem to be nutrient loading and poor land use in North Carolina and high human population density and growth in Florida. The future utilization of these estuarine systems and their services will depend on the development of improved management strategies based on improved data quality.

Effects of Catchment Activities on Macrofaunal Assemblages in Tasmanian Estuaries

Silt loadings associated with human activities in catchments were inferred to have an extremely widespread effect on estuarine macrobenthos around Tasmania. Estuaries with human population densities exceeding 10km−2in catchments consistently possessed muddy rather than sandy beds and shores, and were dominated by infauna rather than epifauna. Estuaries with human population densities below 1km−2in catchments possessed sandy sediments and numerous epifaunal species. These effects were consistent within groups of estuaries possessing similar hydrology and geomorphology. Although faunal composition differed substantially between estuaries possessing low and high human population densities, the number of macrofaunal species was similar. Population effects therefore could neither be detected using species richness indices, nor by the ABC method. Faunal changes were most clearly detected using disturbance indices weighted by the sensitivity of individual species to human activity. Two such indices, which are based on abundance (DIn) and productivity (DIp) data, are suggested to provide useful local indicators of estuarine health.

Human contact with bait containing vaccine for control of rabies in wildlife

Objective To document the number of human contacts with bait containing liquid vaccinia-rabies glycoprotein (V-RG) vaccine, to evaluate factors that might affect human contact with bait-vaccine units, and to summarize adverse reactions in people after contact with vaccine. Design Retrospective 4-year survey of directors of 6 oral rabies vaccination programs. Sample Population Human residents in areas of vaccination programs. Procedure Data were collected from report forms and telephone conversations with directors of oral rabies vaccination programs in Florida, Massachusetts, New Jersey, Texas, and New York. Data collected included information regarding human contact with bait and vaccine, sex and age of person involved in contact, human population density, bait density, type of labeling used on bait, and other factors. Results Human contact with bait was more likely in areas where bait had white labels (vs lettering in black ink) and in areas with high human population densities. Directors of all programs reported that human contact with bait-vaccine units was minimal. Adverse reactions in exposed people were not reported. On the basis of these findings, concerns about V-RG vaccine posing a substantial public health risk remain unfounded. Clinical Implications Directors of oral rabies vaccination programs should systematically collect information about exposures and potential factors affecting exposure of people to bait-vaccine units. People with substantial exposure to V-RG vaccine should be evaluated for immune status and any resulting symptoms should be documented and monitored. (J Am Vet Med Assoc 1998;213:1413-1417)

Changes in otter Lutra lutra distribution in Central Spain in the 1964–1995 period

Surveys carried out in 1964, 1984 and 1995 of otter Lutra lutra distribution were compared in order to analyze its changes in distribution in Central Spain. These changes were studied from different areas defined by their physiognomy and human population density. During the 1960s, the species was well distributed throughout the study area but this was followed by a decline and a more recent recovery. Several negative factors (i.e. pollution, human disturbance, habitat destruction, hunting) extinguished or fragmentated some populations. During the last period (1990s&/it;) some populations have recovered, probably through recolonization from neighbouring areas supporting healthy populations. Variations in a water quality index and human density were considered to be potential explanatory causes of changes in otter distribution. The current otter distribution is probably very influenced by movements between different areas. High human population density and physical barriers (mainly mountains) can be considered as the principal factors limiting otter movements. This paper emphasizes the importance of studying local population dynamics in order to plan an effective long-term conservation strategy.

Trichinella britovi in Foxes in the Netherlands

An overall prevalence of 3.9% of Trichinella infection was observed in the fox population in The Netherlands. Random amplified polymorphic DNA analysis of individual muscle larvae demonstrated the presence of Trichinella britovi. This is the first report of T. britovi, etiological agent of sylvatic trichinellosis, in one of the most densely populated countries in Europe and, consequently, the occurrence of cannibalism and scavenger behavior of foxes in areas with a high human population density. The presence of T. britovi in the fox population in these areas appears to be without consequences for commercial pig farming.

Increasing rabies vaccination coverage in urban dog populations of high human population density suburbs: a case study in Nairobi, Kenya

The incidence of rabies in dogs is increasing in many regions of Africa, despite the commercial availability of effective vaccines for dogs. The major constraints to effective dog vaccination programmes are poor accessibility of dogs for vaccination, inadequate availability of vaccines in some countries and the relative high cost of vaccines. A study was carried out in a suburb of Nairobi, Kenya, with a high human population density, to evaluate levels of dog vaccination coverage that could be achieved through better vaccine delivery techniques. Using more vaccination teams, extended times and door-to-door vaccination, and timing vaccination to coincide with school holidays, an estimated vaccination coverage of 68–75% was achieved in the study area over a 5 day period. This compared very favourably with the low vaccination coverage levels, estimated to be less than 4%, achieved in the 2 years prior to the study in Nairobi as a whole. The need for a better understanding of dog ecology in such urban communities, as well as ways of improving vaccination delivery and sustainability coverage, are discussed.

Status of the Greater Flamingo in Haiti

-Although flamingos in Haiti can still be found in most areas of their historical range, survey results indicate that numbers have declined drastically over the last 50 years. The coastal mangrove lagoons between Grand Saline and Gonaives, the inland lakes of Etang Saumatre and Trou Caiman, and Ile de la Gonave have been, and remained, the major areas used by flamingos. The species has been extripated from areas with high human population densities (Ile a Vache, Les Cayes, and Cap-Haitien). No evidence of breeding activity was obtained. The last nesting colony known to occur in Haiti was reported in 1928. Available data suggest that Haiti is mostly utilized by flamingos for feeding and roosting during non-breeding, winter dispersal from Great Inagua, and perhaps Cuba. Flamingo numbers in Haiti are estimated at about 900 (? 600) birds. Population trends in Haiti are likely declining due to increasing human disturbance, habitat degradation, and exploitation for food and trade. Received 5 January 1989, accepted 19 April 1990.