Macroinvertebrates of Anza-Borrego by Night and Day Spencer Breining-Aday, Damin Curtis, Elizabeth Davis, Rachel Liu, Serena Stumpf

Why Macroinvertebrates?

Desert Environment Extreme temperatures Limited habitat Heat stress Limited water and desiccation Environmental stresses affect macroinvertebrates The composition and distribution may change between night and day The composition and distribution may change at different locations

Do desert macroinvertebrate communities differ between night and day at different locations?

Methods 4 Transects, each 45 m long 10 pitfall traps per transect 2 day samples and 2 night sample one pitfall each 5 meters Placed in the wash, the north slope, the ridge, and the south slope (not to scale)

Methods Every morning we left at 6am and in the evening we left at 7pm to collect the data We poured our pitfall trap cups into falcon tubes and labeled them to make it easier to carry it down the ridge

Methods Categorized by order and morphotype Kept one of each morphotype to use as a reference We figured out which order it belonged to and gave it a morphotype number. For instance coleoptera 1 Poured our samples out onto a plate, moved all of the macroinvertebrates to the side and compared them to our references

Quantifying Abundance Total abundance = sum of individuals from all morphotypes in a sample Day: 13hrs Night: 11hrs Total abundance / # of hours = Hourly abundance Comparable between day and night

Refining our Test Single Factor Multi-Factor Night vs. Day F Ratio: 1.2 P: 0.28 Site F Ratio: 4.9 P: 0.0025 Night vs. Day F Ratio: 1.3 P: 0.25 Site F Ratio: 5.2 P: 0.0019

Results: Abundance Overall: No significant difference between day and night Between each site: There is a significant difference F Ratio: 3.35 *P < 0.05 Hourly Abundance Day Night

Morphotype Richness Ordinal Richness Night vs. Day: p-value<0.05

Within Order Richness Day Orders Night Orders

Within Order Abundance Day Orders Night Orders

What the data means Overall abundance is not significantly different between day and night Overall richness is higher at night There are significant differences between the orders present at day and night. 160 different morphotypes in 2 days

Big picture WHY these patterns? Micro environments Day & Night was pseudo replicated, need to fully replicate

Many Thanks Aviva’s ID help & pictures Blake’s statistics expertise & pitfall help Jodi & Jack & Maddie for sorting help and emotional support

Sources http://www.abdnha.org/wildlife-of-anza-borrego.htm

Sampling Design 4 transects: Wash North facing slope Ridge South facing slope 10 pitfall traps per transect: 45 total

Macroinvertebrates in the Desert Environment Question Introduction Results and Discussion Conclusions Methods Macroinvertebrates in the Desert Environment Nocturnal vs. diurnal