Topics: Biotic component, Abiotic component, Water pollution Pages: 10 (1976 words) Published: April 20, 2015
The aim of my investigation is see if the effect of open and vegetation microhabitats on the abundance of Mayfly Nymph (Latin name- Ephemeroptera). I conducted my investigation at Epping Forest field centre in Loughton, Essex. The grid reference is TQ412981. The Field centre is located in a Site of special scientific interest (SSSI) and a special area of conservation (SAC) [4]. There are many areas of isolated natural ponds however the pond I worked at was Lily pond which is a man made pond. This means that it is more managed than the natural ponds. After considering other ponds to work at I choose Lily pond as there was little leaf litter compared to the natural ponds which made it easier to identify invertebrates in pond samples. Mayfly Nymphs are the invertebrates I choose to study as there is a generally high abundance in Lily pond therefore the changes in abundance in microhabitat can be seen more easily. Ephemeroptera nymph has very short life span as an adult that can last for a day or less than 30 minutes [1]. Figure 1 show the life cycle of Mayfly Nymphs. The adult Mayfly lays its eggs in the pond; the offspring enter the first stage when they hatch as Nymphs. The sub-imago stage shown in Figure 1 is ‘the first flying stage’ [2] and the final stage is the adult stage in which Mayflies mate and then die.

The Nymph stage last longer than the adult stage from months up to years [3]. This is because the adults do not eat and use the energy absorbed at the Nymph stage. The Mayfly Nymph shape varies according to the type of sub-species. Mayfly Nymphs have gills along their abdominal area which can be seen in Figure 2. They have three tails which can create a wave like movement allowing the Nymph to swim [1]. These are structural adaptations that enable the Mayfly Nymph to survive in a pond ecosystem.

Mayfly nymph are ‘usually vegetable feeders’ and many feed on algae [1]. Vegetation and algae are autotrophs that are able to make complex molecules such as glucose through the process of photosynthesis. After loss of energy through respiration the total energy remaining is called net primary productivity. This energy is the ‘available to herbivores’ such as the Mayfly Nymph. However not all of the energy will be transferred to the Mayfly as some of the plant material may not be digested [5]. Mayfly nymph have important role in the food chain which can be seen in Figure 3, as it provides a pathway for energy to be transferred across tropic levels. Figure 3 also shows some of the predators are carnivorous water beetles, Dragonfly Nymph, Water Boatman and Newts.

Mayfly Nymphs in the pond live in different microhabitats. Microhabitats are smaller habitats with a larger one [5]. Figure 4 shows the different microhabitats found in a pond. The detritus is a microhabitat at the bottom of the pond where dead plants and animals are found..Vegetation is a microhabitat that contains both Submergent and Emergent plants. Submergent vegetation is found below the surface of the water and the emergent vegetation is above the surface. Open water microhabitat can be described as an area which does not contain vegetation.

The independent variable in my study was the type of microhabitat. My dependent variable was the abundance and size of Mayfly Nymph. In my investigation I will not be observing Mayfly Nymphs in the detritus microhabitat as the dependent variable was easier to compare as there is not as much dead plant material in the other microhabitat. Figure 4 shows areas I looked at during my investigation at Lily pond.

Abundance of an organism is affected by both abiotic and biotic factors in the ecosystem. Abiotic factors are non-living part of an organisms habitat and the biotic factors are the living part [5]. Shelter is an abiotic factor that can affect abundance as it may provide safety for an organism...
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