Invertebrates as Indicators of Human Impact on Soil

1. Invertebrates as Indicators of Human Impact on Soil “How do invertebrate populations change with soil compaction?”

2. Exposure to Pollution Human Impact Bug Species Diversity And As My First Model Initial Question: How are surface and underground bug populations different in areas that have experienced industrial pollution versus areas that have experienced mild human development and areas relatively undeveloped and not exposed to recent pollution or human activity?

3. Ratified Ideas Failure to collect sufficient data indicating site pollution history combined with faulty data collection techniques Resulted in a revised question and model

4. Human Activity Soil Compaction Aeration Nutrient Content Drainage Insect Population/ Diversity Revised Model: Question: Are insect populations different in habitats characterized by serious, moderate and minimal soil compaction? Which insects survive better in areas with soil compaction?

5. Assumptions • Invertebrates could be used as an indicator species for soil compaction • Soil density is a measure of compaction • Soil sample collection method is accurate enough to determine relative density of various soil samples

6. A little background… • In a study by Lindo and Visser it was determined that certain species of micro-arthropods could be used as an indicator species for human disturbance in the form of forest clear cutting and that the factors most likely influencing the changes in species diversity and abundance are soil compaction and changes in food availability Significance… • Study findings may support assumption #1 that invertebrates can be used as an indicator of soil compaction

7. Site Selection • Three locations at Discovery Park suspected of having different soil densities were selected for this experiment. • Site #1on a main path leading from the visitor’s center to the loop trail • Site #2 on a less popular path leading behind the visitor’s center • Site #3 located 30 paces off the path containing site #2

8. Location Selection • 2 data collection locations and 1 soil density control location are selected for each site. • At sites 1 & 2 the data collection locations are placed off center of the path to prevent foot traffic interference. • Control locations are 2 paces off the path for sites 1 & 2 and 2 paces from one of the data collection locations for site 3.

9. Determining Soil Density/Compaction • Insert a standard bulb planting tool into the soil up to the 2” mark • Place soil from bulb planting tool into a standard 1 gallon freezer bag • Weigh soil samples using a triple beam balance • Density=Mass/Volume • Density can be compared via mass measurements because all volumes should be constant

10. Soil Densities by Site

11. Insect Collection Procedures • 1 pint glass jars are buried in the soil with lip even to the ground • Leaves are tented over the jar opening to prevent outside interference in data collection • Jars are left in place for 96 hour periods and checked for insects every 48 hours Boat-backedBeetle Common Black Ground Beetle

12. Invertebratesby Location

13. What it all means… Is there a connection between soil density and invertebrate populations size and diversity? YES!

14. Human Activity Density Soil Compaction Aeration Nutrient Content Drainage Insect Population/ Diversity Conclusions: 1. Soil density has a visible effect on invertebrate populations.

15. Conclusions: 2. For soil compaction to affect insect populations, the compacted area must be larger than the width of the paths chosen for this study. 3. The insect populations sampled for this study most likely reflect the populations found in areas with soil compaction equivalent to the control areas.