Practical Field Ecology. C. Philip Wheater. Читать онлайн. Newlib. NEWLIB.NET

Автор: C. Philip Wheater
Издательство: John Wiley & Sons Limited
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Жанр произведения: Биология
Год издания: 0
isbn: 9781119413240
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there can be logistical problems that influence your choice of site, or species, or otherwise prevent you from proceeding exactly as you would have wished. Although you can avoid many such problems by careful planning, there are some aspects that you will not think about until you implement the research. A pilot study will help to identify such issues and may allow you to refine the study in advance of full implementation. If you are unable to do a pilot study, at least try to explain your approach to someone who has spent time doing ecological fieldwork. They may highlight some obvious deficiencies. This is particularly useful for field trips abroad, which preclude a pilot and can be fraught with difficulty.

Flowchart of the planning considerations for research projects.

      Box 1.1 Some sources of ecology projects

      Natural England has a list of research ideas on their national nature reserves https://www.gov.uk/government/publications/research-opportunities-on-national-nature-reserves-in-england

       The Practical Ecology Series provide project ideas associated with grasslands (Brodie 1985), freshwaters (Gee 1986), the seashore (Jenkins 1983), and urban areas (Smith 1984).

       Routledge Habitat Guides each include a section (section 5) giving project ideas for the habitats associated with grasslands (Price 2003), uplands (Fielding and Howarth 1999), urban habitats (Wheater 1999), and woodlands (Read and Frater 1999).

       The Biology of Habitats Series covers a wide range of global habitat types and includes practical aspects of working within the habitat and some of the types of studies that are possible within them (e.g. Rydin and Jeglum 2013 for peatlands and Little et al. 2009 for rocky shores).

       The Naturalists' Handbook Series (now published by Pelagic Publishing) contains many ideas related to studying a group of species (e.g. Gilbert 2015 on hoverflies or Roy et al. 2013 on ladybirds), or different habitats (e.g. Hayward 2015 on sandy shores or Wheater and Read 1996 on animals under logs and stones), or implementing different techniques (e.g. Unwin and Corbet 1991 look at insects and microclimate, whilst Richardson 1992 examines pollution monitoring using lichens).

      Having decided on a provisional topic, the next step in the successful planning of any research project is to identify those questions you wish to ask and then to formulate the aims and objectives. There are various reasons for researching particular plants, animals, or environments and this section provides a quick overview of the scope of ecological projects.

      Many studies involve monitoring the number of species, number of individuals (relative abundance), estimates of population size or density (absolute abundance), or community structure (diversity, evenness, and richness). Additionally, studies on animals may require observations of the behaviour of individuals or groups and their interactions with each other and their environment.

      Monitoring individual species and groups of species

      Monitoring species richness

      In studies examining species richness, you might be interested in the presence or absence of one or more species (or other taxonomic group) in order to investigate the links between such species and aspects of the environment; for example, in terms of the ecology of the species concerned, or in studies of pollution where the species may be useful as a biological indicator of certain toxins. Here, simply listing the plants and animals present may suffice. Although this may appear to be a quite simple approach, care needs to be taken to ensure that sampling techniques are used that are appropriate to both the organisms under consideration and the habitats in which they are found. For example, studies on bird species richness in urban parks may be complicated if some parks are dominated by relatively open habitats of amenity grassland and formal flower gardens, whilst others feature dense shrubberies and even woodland. Observations of the species present may be easier in the open habitats than under dense canopy. Care will thus be needed to ensure that all species are counted (as accurately as possible) using the most appropriate method for that site or habitat type. For these reasons, issues around surveying habitats and sampling organisms are considered in the next three chapters.

      Monitoring population sizes and density

      In population and density studies, it is the number of plants or animals of particular species that is of importance. Such studies may look at the number per unit area (i.e. the density) or calculate estimates of population sizes. Densities are taken from the estimated population size divided by the size of the area sampled. However, for mobile organisms it may be difficult to identify the spatial limits of the population (e.g. in studies of butterflies, some species may be highly mobile with individuals not being restricted to defined small sites). Under such circumstances, densities may be less useful than estimations of population sizes of the animals using particular sites. If populations of several species are being studied, then it is important to ensure that the sampling methods used are appropriate to all the species being monitored. For example, in rainforests, some species of butterflies are found mainly within the canopy and are only occasionally caught at ground level and, conversely, some are predominant at ground level. Clearly, any survey comparing such study sites should incorporate sampling at both levels.