Sampling of Terrestrial Invertebrates - Lab Report Example

Sampling of Terrestrial Invertebrates: Community Similarity and Diversity within a forest on the Saint Leo Campus Name: Due date: Professor Wilder Name of the Course I. Introduction This lab assignment gives us an insight about the invertebrates in the forest within the St.Leo campus. The assignment lets us understand the species diversity, richness and evenness within the given location. The field procedure enables us to perform different sampling techniques for the same purpose i.e. investigation and enumeration of the different invertebrates with the transect locations. We utilized the concept of random sampling since we were unaware as to how many different kinds of species of insects we would encounter. Therefore, during our transects each species present in the locality had equal probability of being sampled. Now, the entire concept of sampling itself is very important for scientific endeavors because it helps us establish our proposed purposes. Sampling gives us a real picture of the community diversity and similarity between habitats. Species diversity and species similarity can be calculated using the Simpsons Index Diversity and Jaccard Coefficient respectively. Simpsons Index diversity gives an account of the number of different species present. It also accounts for the abundance of the species. Jaccard Coefficient is a comparative study that is employed to obtain an idea about the species similarity and also species diversity among a number of communities. In our endeavor to sample and study terrestrial invertebrate communities we used three different sampling techniques for 3 different communities under study. Community A consists of terrestrial invertebrates that mostly live among vegetation and have the ability to fly. For them we employed the Sweep net sampling technique. In this sampling techniques a sweep net is moved in a sweeping motion as one moves among vegetation in the transect. The insects captured in the net are then collected and taken for further study. Community B consists of those invertebrates that mostly live on the ground among dry leaves. For this community we used the leaf litter sampling method also known as the Berlese funnel technique. In this technique we collect leaf litter from the ground and place them in plastic bags which are then taken to the lab. In the lab the litter is placed in specilised Berlese funnel that comes with a mesh lining and the entire set-up is kept under light bulbs that provides warmth and dryness which drives out many of the invertebrates hiding in the litter which are driven to the lower part of the funnel and eventually fall into ethanol. After this they may be used for further study. Community C consisted of roving terrestrial invertebrates for which we used the pit-fall technique of sampling. For this, a transect area is selected and holes are dug out every 5 meters. Plastic cups are placed in the dug- out holes taking care to keep the rim at level with the ground. Some preservative is poured into these cups. Crawling insects will happen to fall in the cups which can later be taken out of the holes and used for studies. II. Materials and Methods A. MATERIALS The materials used are as follows: Trowel/short shovel Gloves Magnifying glass Rope Pencil and paper Cups Sweep nets Collection bags Ziploc bags Plastic bags Mineral oil B. METHODS Three different sampling techniques were used for the three different communities: Sweep net technique: Two groups are made and transect (50m) is selected. Two students held the net and swung it back and forth while walking in an herbaceous area. Samples collected in the net are brought back to the lab. Leaf Litter sampling: A handful of leaf litter is collected from two different places and placed in Ziploc bags Transported to lab for investigation Pitfall sampling A transect of 50 m is chosen Cups are filled with mineral oil A small hole is dug in the ground Cups are placed with the rim just touching the surface Cups are placed every 5 meter in the 50m transect Sweep Net Sampling: 2 groups are separated and each group selects a transect of 50m 2 students in each group handle the sweep net and swing it back and forth The insects are collected and brought back to lab III. Results Everything around us is an ecosystem or a part of an ecosystem. Ecosystems are complex and there are various components that need to be understood to get an idea about the entire ecosystem. For the purpose of such studies ecological sampling is really important. Ecologists and biologists use ecological sampling techniques for various kinds of field and laboratory studies. Most of these studies are done to obtain more knowledge about the animal kingdom, animal classification, animal characteristics and behavior etc. From our study using the three sampling techniques we obtained a detailed data of the communities of invertebrates living in the transect location. The number of species in each community was different. For community A we obtained 15 different species, for community B and C we obtained 5 different species each. We studied the diversity of the 3 communities and saw that community A was more diverse. Community B diversity was very close behind followed by Community C. In fact the values of the diversity index clearly shows that there is an appreciable diversity of invertebrates present in the transect location. There was not an appreciable difference between the diversity indexes of the 3 communities however community A showed greater diversity because of vegetation abundance. The randomness of the methods employed could also have been the cause because sweep net technique is less random than the other techniques. The data collected was also used to plot 3 abundance-rank graphs. The slope of the line in the graph is a good proof of the species evened and species diversity. The graph clearly shows that Community A is more diverse since the slope is less and there is presence of more number of species compared to the other 2 communities. Community A has species evenness which is again shown by the low slope. IV. CONCLUSION According to the calculation we obtained Community A was far more diverse and species rich. The rank-abundance plotting for the three communities may be used to explain Our assignment results showed that even though we sampled the invertebrates from nearly located areas Community A i.e. those invertebrates living on the herbaceous front were far diverse and spread evenly. APPENDIX Fig 1: Satellite view of Transect locations in the Saint Leo Forest   Fig2 : Rank abundance curve for community A Fig3: Rank abundance curve of Community B Fig 4: Rank abundance curve of community C Table 1: Simpsons Index of diversity : Community A Species Number (n) n (n-1) Asian tramp snail 8 56 Tachinid fly 9 72 Ear-wig 4 12 blackfly 2 2 Caterpillar 1 1 0 Caterpillar 2 1 0 camponotus 1 0 Leaf-hopper1 6 30 Leaf-hopper 2 4 12 Wolf spider 1 0 Spider 1 2 2 Grass hopper 3 1 0 Tree frog 1 0 Got happer 1 0 Coleoptra 1 1 0 cricket 1 0 pygmy 1 0 ophion 1 0 Homoptera rolly polly 1 0 mormidea 2 2 Stink bug 4 12 Round beetle 1 2 2 Photoris peenysalvanica 1 0 TOTAL NUMBER 56 Total n(n-1) 200 Table 2: Simpsons Index of diversity: Community B Species Number (n) n(n-1) Dermoptera earwigs 2 2 Hymenoptera bee 1 0 Asian tramp snail 18 136 Homoptera rolly-polly 7 42 Spiders 1 3 6 Total 31 Total n(n-1) 186 Table 3: Simpsons Index of Diversity : Community C Species Number (n) n(n-1) Large stink bug 1 0 Wolf spider 1 0 orthoptera 1 0 Field ant 1 0 Florida trap jaw ant 3 6 Pygmy mole cricket 2 2 Diptera 1 (small fly) 1 0 Total number 10 Total n(n-1) 8 CALCULATION OF SIMPSONS DIVERITY INDEX Since we had a finite population we use the second version for calculation: D = Ʃ(n / N)2 D= n = the total number of organisms of a particular species N = the total number of organisms of all species  Community A The total number of organisms of all species was calculated and the values were put into the equation. We get a value of 0.064. Community B The total number of organisms was taken and the index was calculated. It was seen that the Simpsons diversity index was 0.13. Community C The Simpsons diversity index was calculated and we obtained a value of 0.08. Table 5: Jaccard Coefficient for Communities A,B AND C Community A Community B Community C Species Number (n) Species Number (n) Species Number (n) Asian tramp snail 8 Dermoptera ear wigs 2 Large stink bug (Hemiptera) 1 Tachinid fly (diptera) 9 Hymenoptera bee 1 Wolf spider 1 Ear-wig 4 Asian tramp snails 18 orthoptera 1 Blackfly (Diptera) 2 Homoptera rolly polly 7 Field ant 1 Caterpillar 1 1 Spider1 3 Florida trap jaw ant 3 Caterpillar 2 1 Total 31 Pygmy mole cricket 2 Camponotus (carpenter ant) 1 Diptera 1 1 1 Leaf-hopper1 6 Total number 10 10 Leaf-hopper 2 4 Wolf spider 1 Spider 1 2 Grass hopper 3 1 Tree frog 1 Got happer 1 Coleoptra 1 1 cricket 1 pygmy 1 ophion 1 Homoptera rolly polly 1 mormidea 2 Stink bug 4 Round beetle 1 2 Photoris peenysalvanica 1 TOTAL NUMBER 52 Community Similarity-Jaccard Coefficient We use the Jaccard coefficient to compare the 3 communities and investigate the similarity between them Calculation: We use the following equation: CCj = c / s1 + s2+s3 – c Here Where CCj is the coefficient of community (or Jaccard coefficient), c is the number of species common to both communities s1 and s2 and s3 are the number of species found in both communities. c= 1 s1= 15, s2=5, s3= 7 CCj= 1/26 0.03 Thus the Jacquard Coefficient is 0.03. REFERENCES Dogramaci, Mahmut. "A method for subsampling terrestrial invertebrate samples in the laboratory: Estimating abundance and taxa richness." Journal of Insect Science10.25 (2008): 1-15. Web. . Lavelle, P. "Soil invertebrates and ecosystem services." European Journal of Soil Biology42.1 (2006): s3-s15. Print. Michael J. Wilder, community diversity, Ecology Lab, Sampling of Terrestrial Invertebrates: Community Similarity and Diversity, Saint Leo University Read More