Influence of Leaves and Woodland debris on rate and Pattern of Cadaver decomposition Emily Fisher Supervisor: Sanita Nezirovic [email protected] [email protected] Taphonomy is a relatively new field in forensic science, one of the most crucial methods for taphonomy was the invention of the body scoring method by Megyesi et al., (2005). This method uses scoring of body areas through visual cue, such as colouring, bloat and purging. However there are many variables that effect the accuracy of this method. Mann et al., (1990) looked at some of those variables and ruled temperature, insect access and burial depth as the most important. However there is limited amount of research on the effect of coverings and leaves. Olakanye (2017) looked at leaves compared to carcasses but laid out separately. The study identifies how rate and pattern of decomposition of a piglet (Sus Scrofa There are two hypotheses for this study: Domesticus) is affected when leaves and woodland debris are covering it.

H0: Placing leaves and woodland debris over a carcass will not affect the rate of decomposition. RESULTS H1: Placing leaves and woodland debris over a carcass will affect rate of decomposition Figure 1 shows that the experimental piglets started decay later than the control piglets, however they reached full decomposition prior to the control piglets. The H0: Placing leaves and woodland debris over a carcass will not affect pattern of decomposition control piglets were slowed in decomposition at 213ADD until 266ADD. Whereas the H2: Placing leaves and woodland debris over a carcass will affect pattern of decomposition experimental piglets started decomposition at 155ADD, where they rapidly decomposed and finished (TBS=32) 81ADD prior to the control. METHOD - Six pre- frozen still born piglets all weighing 500g (+/-200g), four experimental and two As shown in figure 2, the head of the experimental piglets started decomposition control, they were sourced from a farm used for human consumption first (109 ADD), then the torso at 133ADD and finally the limbs at 155ADD, they then - Located in a wooded area, in the centre of derby ran almost parallel in pattern of decomposition, however the head was more rapid - Data collected everyday at 12pm (+/- 1hr), photographs were taken of the piglets; with at decomposition after it reached a partial body score of 7. leaves, head/ torso/ limbs without leaves - Accumulated degree days Moffatt et al. (2016) for the rate and total body score by Keough Figure 3 shows decomposition in the control piglets took longer than the (2017) for the pattern of decomposition. experimental piglets. However all body areas started decomposition sooner. The - Environmental data was collected which included two rain gauges (max: 50mm/ 2.0inch), head rapidly decomposed until it reached a partial body score of 9. At times, the temperature (data loggers) wind speed (anemometer), and light (lux meter) limbs decomposed quicker than the torso, with it reaching full decomposition - Randomised samples of wet leaves collected from the wooded area that the burial compound (PBS=10) first. is located in. Over 75% of the sample was English Oak - The sample of leaves placed into a bag which had a line indicating where to fill it, then tipped Humidity was measured and the R Squared value equalled 0.999 when the Adjusted on top of the piglet. R squared value was 0.953. For Temperature, the R Squared value was 0.921, when - Two- way Anova’s were also completed for the environmental data including humidity, the Adjusted R squared value was 0.612 and the R Squared value for rainfall was temperature and rainfall. 0.636 when the Adjusted R squared value was 0.282. Rate of Decomposition for Experimental Piglets Compared to Control Piglets 35 30 Expe rime nt al Control 25 piglet at 257ADD 20 Figure 4: A control TBS: 19 15 10 5 0

Average Total Average Body Score (TBS) 14 32 51 75 98 121145164185203222240257272285303322340357367 Accumulated Degree Days Figure 1: A comparison graph for the rate of decomposition for experimental against control piglets TBS: 27

Pattern of decomposition for Experimental Piglets Figure 5: An experimental piglet at 257ADD 14 Pattern of decomposition for Control Piglets Head Tor so Limbs 12 14 Head Tor so Limbs 10 12

8 10

6 8

4 6

2 4 Average Partial BodyAverage Score (PBS)

0 2 Average Partial BodyAverage Score (PBS) 14 25 32 39 51 63 75 86 98 109 121 133 145 155 164 175 185 193 203 213 222 232 240 248 257 266 272 280 285 291 0 Accumulated Degree Days 14 32 51 75 98 121 145 164 185 203 222 240 257 272 285 303 322 340 357 367 Figure 2: A comparison graph for the pattern of decomposition using partial body score for Accumulated Degree Days experimental piglets Figure 3 : A comparison graph for the pattern of decomposition using partial body score for control piglets

CONCLUSIONS The results of this study show that leaves and woodland debris do affect rate and pattern of decomposition. The null hypothesis for rate of decomposition, and the null hypothesis for pattern of decomposition were rejected. There was a clear indication that the rate of decomposition was affected with the experimental piglets reaching full decomposition one week prior to the control piglets.The study found that humidity was the most important variable with it being 95% responsible for the change in decomposition between experimental and control piglets. It is likely that this humidity affected the rate and pattern of decomposition as well as the decay of the leaves. There was no clear correlation of the effect of temperature to the control or experimental piglets, however the statistical analysis showed that temperature was 61% responsible for the change in decomposition between the control and experimental piglets.

It is recommended that a repeat study is completed with a larger sample size, and the variables measured more closely, it is also likely that disturbances to the leaves will affected both the temperature and humidity, so it is recommended that further research also includes samples that are undisturbed. Further research should be completed with larger pigs, in order to replicate an adult human, rather than a juvenile. Mann, R. W., Bass, W. M. and Meadows, L. (1990) ‘Time Since Death and Decomposition of the Human Body: Variables and Observations in Case and Experimental Field Studies’, Journal of Forensic Sciences, 35(1), pp. 103-111 Megyesi, M., Nawrocki, S., and Haskell, N., (2005) "Using Accumulated Degree-Days to Estimate the Postmortem Interval from Decomposed Human Remains," Journal of Forensic Sciences, Vol. 50, No. 3,, pp. 1-9, Olakanye, A., Nelson, A., Ralebitso-Senior, TK,. (2017) A comparative in situ decomposition study using still born piglets and leaf litter from a deciduous forest. Forensic Science International. Vol. 276. pp. 85-92