Populations In Protected Areas Research Articles

The effect of water movement, temperature and salinity on abundance and reproductive patterns of Macrocystis spp. (Phaeophyta) at different latitudes in Chile

This study describes the density variation and phenology of Macrocystis integrifolia and M. pyrifera populations from northern and southern Chile, respec- tively. Samples of both species were taken in wave-ex- posed and wave-protected areas. In addition, spore production, germination and early growth rate of sporophytes of each population was studied at monthly intervals under three temperature and salinity regimes. Results indicate that M. integrifolia from northern Chile presents perennial plants with a mean density of three individuals per 0.25 m 2 throughout the year and that it reproduces mainly during spring and winter. Although, M. pyrifera in exposed areas of southern Chile also have a perennial-type life strategy, they are able to reproduce all year round. In contrast, M. pyrifera populations in protected areas of southern Chile show a clear annual cycle, with high recruitment during late winter and fer- tile sporophytes in summer and autumn, although the populations become completely decimated thereafter. The effect of temperature and salinity on M. integrifolia shows that it is independent of water movement, but requires low temperatures and high salinities for the release of zoospores, germination and early sporophyte growth. This pattern differs from that of M. pyrifera in southern Chile, which has a broader tolerance range for salinity and temperature than does M. integrifolia. However, in southern Chile wave-protected populations showed higher spore release and germination at 15� C and 18� C, whereas sporophyte growth responded better at the lowest temperature tested (8� C). In general, these results are contrary to those expected, since a seasonal reproductive pattern was observed in M. integrifolia inhabiting a less seasonally variable environment. In exposed sites of southern Chile, plants showed greater tolerance and continuous reproduction throughout the year, despite the greater environmental variability. Finally, population dynamics of protected kelps in southern Chile shows an annual pattern, which is contrary to the expected perennial strategy shown by exposed populations.

Conservation of argali Ovis ammon in western Mongolia and the Altai-Sayan

Management of argali in Mongolia historically has been tied to improving biological research and anti-poaching activities within the framework of trophy hunting. Argali populations in protected areas, where trophy hunting does not occur, have received little attention, and conservation or management plans for these areas generally do not exist. In this study, results from interviews with pastoralists in Siilkhemiin Nuruu National Park in western Mongolia indicate that local people revere argali and are generally aware of and support government protections, but may not be inclined to reduce herd sizes or discontinue grazing certain pastures for the benefit of wildlife without compensation. Because past protectionist approaches to argali conservation in western Mongolia and the greater Altai-Sayan ecoregion have not achieved effective habitat conservation or anti-poaching enforcement, alternative management policies should be considered. Results from this study suggest local receptiveness to management programs based on community involvement and direct benefit.

Range contractions in the Critically Endangered Seychelles terrapins (Pelusiosspp.)

AbstractThe status of the Seychelles endemic terrapins is reviewed based on field-surveys.Pelusios castanoides intergularisandP. subniger parietalisare confined to a small number of marshes and rivers. All the sites occupied are limited in area (<4.5 ha) and under threat from drainage, predation and invasion by alien water plants. The smallest populations are unlikely to be viable in the long-term. Both species can be categorized as Critically Endangered using the IUCN Red List categories, with highly restricted ranges (2.89 and 6.02 ha forP. castanoidesandP. subniger, respectively) that have decreased by over 50 per cent in recent years. Conservation of these species requires both the protection of wetland habitats and the establishment of new populations in protected areas. A captive breeding programme has been established with the aim of reintroducing juveniles into secure reserves. The endemic speciesP. seychellensismay be extinct.

Range contractions in the Critically Endangered Seychelles terrapins (Pelusios spp.)

The status of the Seychelles endemic terrapins is reviewed based on field-surveys. Pelusios castanoides intergularis and P. subniger parietalis are confined to a small number of marshes and rivers. All the sites occupied are limited in area (<4.5 ha) and under threat from drainage, predation and invasion by alien water plants. The smallest populations are unlikely to be viable in the long-term. Both species can be categorized as Critically Endangered using the IUCN Red List categories, with highly restricted ranges (2.89 and 6.02 ha for P. castanoides and P. subniger, respectively) that have decreased by over 50 per cent in recent years. Conservation of these species requires both the protection of wetland habitats and the establishment of new populations in protected areas. A captive breeding programme has been established with the aim of reintroducing juveniles into secure reserves. The endemic species P. seychellensis may be extinct.

A population survey of the estuarine crocodile in the Ayeyarwady Delta, Myanmar

The estuarine crocodile Crocodylus porosus was formerly abundant in coastal regions of Myanmar, but is now known principally from the lower Ayeyarwady Delta. We conducted a survey during January 1999 to assess quantitatively the status of crocodile populations in protected areas of the lower delta. Spotlight counts were conducted along 275.4 km of waterways. Sixty-one crocodiles (50 juveniles, 4 subadults, 2 adults and 5 eyeshines) were observed in the Meinmahla Kyun Wildlife Sanctuary (MKWS), and the total population was estimated to be less than 100. The Kadônkani and Pyindaye Reserved Forests (RF) apparently no longer support viable populations. Although crocodiles remain critically endangered in the region, a comparison with survey data from 1980 suggests localized recovery is occurring in MKWS. Population declines are attributed to a combination of commercial skin hunting, habitat loss, drowning in fishing nets and over-collection of living animals to supply crocodile farms. A programme of law enforcement, habitat protection and head-starting juveniles is necessary to ensure the continued survival of estuarine crocodiles in the Ayeyarwady Delta.

A population survey of the estuarine crocodile in the Ayeyarwady Delta, Myanmar

AbstractThe estuarine crocodile Crocodylus porosus was formerly abundant in coastal regions of Myanmar, but is now known principally from the lower Ayeyarwady Delta. We conducted a survey during January 1999 to assess quantitatively the status of crocodile populations in protected areas of the lower delta. Spotlight counts were conducted along 275.4 km of waterways. Sixty-one crocodiles (50 juveniles, 4 subadults, 2 adults and 5 eyeshines) were observed in the Meinmahla Kyun Wildlife Sanctuary (MKWS), and the total population was estimated to be less than 100. The Kadônkani and Pyindaye Reserved Forests (RF) apparently no longer support viable populations. Although crocodiles remain critically endangered in the region, a comparison with survey data from 1980 suggests localized recovery is occurring in MKWS. Population declines are attributed to a combination of commercial skin hunting, habitat loss, drowning in fishing nets and over-collection of living animals to supply crocodile farms. A programme of law enforcement, habitat protection and head-starting juveniles is necessary to ensure the continued survival of estuarine crocodiles in the Ayeyarwady Delta.

Conservation in the bush: game breeding centres in South Africa

Approximately 5% of the Republic of South Africa is set aside for national parks, nature reserves, private game reserves or wilderness areas. Within these areas a large variety of animals and plant species is protected. Many of these species are indigenous to the Southern African subregion. Most of the zoological gardens in South Africa are owned privately or by a municipality. The zoo in Pretoria is the only one which has national status. In addition to facilities in Pretoria, the National Zoological Gardens owns two game breeding centres covering an area of more than 7000 ha. The game breeding centres act as important gene pool reservoirs and are used for the breeding of threatened species. They thus fulfill an important role in conserving threatened species and, in some cases, supplementing dwindling populations in protected areas.

Phytoplankton Studies in Lower Narragansett Bay1

A total of 82 surfacc samples were collected at three stations in lower Narragansett Bay from June 1954 through February 1955. Measurements of temperature, salinity, transparency, phosphate, iron, and oxygen were made, and 75 production and nutrient metabolism experiments were conducted.Maximum phytoplankton populations were encountered in September and January, the mean standing crop being considerably in excess of that recorded in adjacent areas. Two hurricanes evoked a vigorous response in the phytoplankton. Skeletonema costatum accounted for 81.2 per cent of the total population. Subsidence of the late winter flowering coincided with minimal phosphate concentrations. The development of the September maximum may reflect a decreased grazing rate. The role of stability and the degree of enclosure in the development of phytoplankton populations in protected areas are discussed.An “atypical” phosphate cycle was encountered in which a summer maximum and a winter minimum occurred. It is postulated that the periods of phytoplankton activity with their accompanying rates of assimilation and regeneration govern this. Three fractions of iron were characterized by marked variations in concentrations.A mean phosphate assimilation rate of 0.087 µg‐at./L/day was obtained; regeneration rates were consistently negative. Iron assimilation had to be expressed as trends. On the average, diatoms increased by 53 per cent per day in the light bottle but decreased by 1.2 per cent per day in the dark one. The effect of this on measurements of respiration and gross production were discussed. Average rates of gross production and respiration were 0.43 and 0.32 ml O2/L/day, respectively. The annual surface production was calculated to be 84 g C/m3 whereas it was 64 g C/m3 during the period of investigation.