Recently, the black carpenter ant (Camponotus vagus) was discovered on the platform of a small station in the most southern part of The Netherlands (Schin op Geul). The nest was situated in one of ...the railway sleepers. Three possibilities are discussed how the species could have arrived at the station: (1) A queen (and maybe her brood) could be imported more than 20 years ago with the railway beams from France when the existing sleepers were replaced. This explanation is improbable because at that time the imported wood was sawed into pieces and creosoted under high temperature and pressure. (2) A (fertilized) queen may have stolen a ride on a train from Germany, which enters that station only twice a year. Also this explanation seems very unlikely to me. (3) A (fertilized) queen may have colonized the area spontaneously by means of flying. It is unlikely that the queen flew out from the nearest known population of the black carpenter ant in Germany (which is situated more than 75 km away), but the existence of populations which are situated more nearby cannot be excluded. It is very doubtful whether this small local population is able to expand. Up till now, no nuptial flights of this species are observed in The Netherlands. However, this thermophilic species may thrive better if the climate becomes warmer.
Nowadays many teenagers are brought to school by car and spend a great deal of their free time watching TV and playing computer games. Lack of opportunities to experience nature may influence their ...perception of nature. Do they miss the flower-rich grasslands and the meadow birds of the past? Do they miss the variety of plants and water animals in the ditches? If we want to convince young people that it is important to conserve biodiversity we have to find out what kinds of preconceptions, ideas and beliefs they have about environmental issues. Are they worried about deterioration of the environment and loss of nature? A survey was conducted among approximately 400 Dutch schoolchildren (age: 8–16 years) in order to test their feelings about deterioration of the environment and the extinction of species. The majority of pupils answered that they regret the extinction of species more or less, especially popular ones. For a minority it does not matter at all. The proportion of pupils who expressed indifference to the pollution of air, water and soil was 7%, 10% and 13%, respectively. Dying of the forest was taken very seriously by approximately 60% of the pupils; this percentage increased after a slide of a dead forest was shown. A similar result was obtained in respect to the assumed extinction of a common plant species: it was taken more seriously after some information was given. More than half of the pupils predicted a bad future for the Netherlands. However, this pessimistic view can be changed into a more optimistic one by stimulating activities to improve the environment. The fact that most pupils judged their own future positive may indicate that they feel to have some control on the quality of their own life.
The survival chance of the trunk ant (Formica truncorum) is compared with the survival chance of two other species of red wood ants: F.rufa and F.polyctena. Nest populations of F.truncorum are much ...smaller than nest populations of the other red wood ant species, which makes the species a weaker competitor. Moreover, F.truncorum has to move more often, as its nests are small and untidily built, which makes the species more dependent on external heat for raising its brood. In order to survive, the greater extinction chance of F.truncorum should be compensated by a greater colonization chance. The colonization chance depends on the number of queens produced, their chance of becoming fertilized and their chance of becoming adopted by F.fusca. It appeared that nest populations of F. truncorum produced less sexuals than those of the other red wood ant species, while there are no good arguments to assume that their queens will have a greater chance of becoming fertilized or that the queens are more skillful in finding a suitable nesting place. It is argued that local populations of the trunk ant are more prone to extinction than those of F.polyctena and F.rufa, at least in the sandy areas of west and central Europe, where most F.truncorum colonies are monodomous and largely also monogynous. So F.truncorum queens should have a greater chance to become adopted by F. fusca than F. rufa and F.polyctena. Adoption experiments can solve this problem.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Governments can use three ways to maintain biodiversity: spatial planning, planning of processes (management) and communication. Good communication between scientists, planners, managers and users of ...urban green areas may be essential to achieve success in maintaining urban biodiversity. In this case study, we have tried to find answers to the question of whether public participation fosters biodiversity by comparing a city in The Netherlands (The Hague), where citizens can participate in decision-making processes, with its twin city in Poland (Warsaw), where the authorities traditionally have not involved its citizens in the planning and management of green areas. The policy plan for green areas in The Hague offers a framework for realizing a sustainable green infrastructure by means of planning, management and use of urban green space. The policy plan describes the status and management of the most important green areas: nature reserves and parks. In this city, it is easy for citizens to obtain information about the management of green areas, but this is very difficult in a city like Warsaw, where management plans are lacking. In Warsaw, much useful information is collected by biologists but only a very small part of the data is provided to, and can be obtained through, the offices of the districts' Department of Environmental Protection. In The Hague, fewer data about the presence of species are collected than in Warsaw, but most of this data can be obtained easily from the Service City Management. Several NGOs in The Hague regularly publish articles about the status of nature within their town and local environment. This stimulates people to observe species and to collect data. The number of volunteers who are active in collecting data on the status of species is still increasing. The collected data are passed to a databank or directly to the managers of the park concerned. The last option will often be consultative, which may lead to empowerment concerning park management. It appears that public participation in the management of green areas will foster recruitment of volunteers who can help to maintain urban biodiversity.
The relationship between aggression and predation was surveyed in Red wood ants, in the field as well as under laboratory conditions. Aggression between wood ant nests is highest in early spring, and ...many wood ant wars break out then. The end of these wars coincides with a strong increase in prey density. Since the casualties are taken as food to the warring nests, a hypothesis is formulated that warfare between wood ant nests only occurs in periods when prey demand exceeds the supply. Protein‐rich food in early spring is mainly for the benefit of the queens and the sexual larvae. Although the most obvious function of warfare is the defence of a foraging area, the main function may be the advancement of the mating flight dates of the queens in order to make the chance of propagating their genes greatest.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Ant species numbers on 18 Frisian islands were analysed in relation to island area, availability and diversity of habitats and distance to conspecific populations, either on the mainland or on ...neighbouring islands. Relationships were quantified by single geometric-mean-regression and stepwise multiple least-square regression. Self-contained species-area curves are presented for the ant faunas within two of the larger islands. Island area and two parameters on environmental diversity could explain c. 90% of the variation in the number of ant species. Effects of isolation were shown to be statiscally significant, but added only 3% to the variance already explained by area. Both the equilibrium model, involving parameters on area and distance, and the habitat diversity approach were equally suitable to describe the distribution of ants in this archipelago, which runs parallel to the coast. An alternative sigmoid model, based on the logistic growth equation, was introduced. It was shown to fit the data as well as the double log-transformed equilibrium model. The sigmoid model also provided an estimation of the species source pool, which approximately agreed with the size of complete regional ant faunas on the mainland of north-western Europe. The ant faunas were further interpreted by using vegetation maps and records on micro-habitat diversity and species-specific habitats. The presence of most ant species was found to be related to the available area of suitable habitat, but some of the rarer species were distributed at random over the islands. Only one species was thought to be absent on nearly all islands as a consequence of insufficient dispersal.
We present a method for involving the invertebrate fauna into nature management by the selection of species indicating effects of fertilization, mowing and grazing on the surface macrofauna of ...grasslands. Low fertilization levels result in the highest numbers of individuals. Grazing results in lowered diversity and a decrease in number of species as compared with no management and with mowing. Mowing results in higher numbers of individuals compared with no management and with grazing. Indicator species are given for assessing the main difference between grasslands which turns out to be fertilization/yield, and grazing. Management effects on the surface macrofauna, the usefulness of the method, and the indicator species concerned are discussed
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