Air temperature and humidity and human comfort index of some city parks of Mexico City

A series of air temperature (Ta) and relative humidity (HR) measurements were carried out in five urban parks and their surroundings in Mexico City. It was found thatTa is lower andRH is higher inside the parks. There were differences (P<0.05) between the parks and surroundings in air temperature, relative humidity, vapour pressure (e), vapour pressure deficit (VPD) and the thermohygrometric human comfort index (THI).Ta differences were more marked during the early afternoon. Maximum differences ofTa, e, andDPV were 5.6°C, 0.6 and 1.2 mbar. There is strong evidence that the magnitude of differences inTa are directly proportional to the surface of urban parks.     

Climate change in conservation areas of South Africa and its potential impact on floristic composition: a first assessment

Projected climate change has been suspected of affecting the biota of conserved nature areas in different and significant ways. Nevertheless, strategic management within some nature conservation agencies appears relatively unprepared for the possible consequences of climate change. National level planning of reserve design networks has also tended to skirt the issue, possibly owing to insufficient analysis. This paper provides a first assessment of the possible effects of climate change on plant diversity within the protected area network of South Africa. A climate change scenario of increased temperature but no change in precipitation resulted in derived optimum growth days increasing in some reserves through increased temperature extending the growing season. In some other reserves optimum growth days declined through greater evapotranspiration. We concentrated on the larger reserves of the latter group for which conditions that are more limiting were predicted. Plant species were evaluated in terms of their critical limits in growth days and minimum temperature. Over a third of the species analysed for one reserve (Augrabies Falls National Park and Melkbosrand) was indicated to become locally extinct with climate change. Another reserve in the region showed fewer than 1% local extinctions. It is clear that although a certain magnitude of climate change is a prerequisite for these extinctions, the rate and number of extinctions depend strongly on the different environmental tolerances of the specific biotic components of the conserved area. Potential immigration of other species to Augrabies Falls/Melkbosrand required to balance the projected extinctions with climate change would need migration abilities and conditions that are unlikely to be met. A net decrease in plant diversity may thus be expected. The results confirm that with the climate change scenario used, the concept of sustaining species through fixed protected areas may be fundamentally flawed, at least in certain areas.     

Monitoring options for visitor numbers in national parks and natural areas

Identifying the physical behaviours of visitors is an essential component of visitor impact management in protected areas. The fundamental baseline information required is visitor numbers, and particularly how these are distributed in time and space across the protected areas. However, obtaining such counts in a reliable and cost-effective manner has proven to be more difficult than commonly expected. Reasons for this difficulty are reviewed, the range of visitor monitoring options available to park managers are described, and the features that park managers want in their visitor counting tools are summarised. The management requirements for implementing and operating an effective monitoring system are also presented.     

Woody plant composition and diversity of urban green spaces in Istanbul,Turkey

Abstract

The high urbanization rate of Istanbul in response to rapid population decreased the size and amount of green spaces. Thereby, every green space types are of vital importance in terms of conservation of urban biodiversity. In this study, it was aimed to compare woody species composition of main green space types consist of artificial and natural sites. Botanical gardens had the highest diversity followed by gardens. Residential areas showed to be important in terms of shrub (52%) and evergreen species (58%), which are mostly exotics (71%). The ratio of the invasive plants in the composition was higher in parks, which contain highway greenings and public gardens. Since the most tree species used in public green areas of Istanbul were mostly same with the species used in European cities, all of the green space categories having varied composition must be considered as interconnected habitat patches in urban planning.     

Season of burning in the Sydney region: The historical records compared with recent prescribed burning

Abstract Prescribed burning is regularly carried out by land management agencies controlling bushland estate in the Sydney region. Despite the volume of research into the interrelationships between fire and Australian ecosystems, season of burning has received comparatively little attention and is poorly understood. This paper considers three aspects of season of burning in the Sydney region, which is located on the boundary of the spring and spring-summer fire season zones, identified by Luke and McArthur (1978). First the paper reviews research on the responses of biota to fire season to establish what is known of the ecological importance of fire season. The historical records of fires in the early period of Sydney's settlement (1788–1845) are then used to determine the seasonal pattern of fire in that period, and the extent to which these records reflect Aboriginal practices which contributed to the historic fire regime. Recent prescribed burning is sampled through the practices of two major land management authorities in northern Sydney (New South Wales National Parks and Wildlife Service and Hornsby Shire Council) to compare current practices with the early records and the ecological evidence. The results of the very limited ecological research on season is far from conclusive. Positive and negative effects have been shown for both autumn and spring with autumn-winter perhaps showing the greater degree of negative impacts, although it is often difficult to separate the effects of season from intensity. The historic records show a pattern of fires, including those lit by Aborigines, largely confined to the fire season of spring-early summer (August to January). By contrast 60% of prescribed burning in northern Sydney by the New South Wales National Parks and Wildlife Service and Hornsby Council from 1980 to 1995 was conducted in autumn-winter (April to July). Prescribed burning in summer cannot be considered for practical reasons but timing of prescribed burning at other seasons is also largely dictated by pragmatic factors such as suitable weather and availability of personnel.