Whittier College ENVS 396 class sampled for arthropods in Zuma Canyon in the Santa Monica Mountains National Recreation Area in the Fall of 2014. Pit fall traps were used as a method of sampling for arthropods. Five pitfall traps were placed in the ground at surface level, in a dice formation. This formation was repeated every 25 meters for 100 meters. This resulted in a line transect totaling of five sample points (5 pitfall traps within each sample point). This method of sampling was replicated at three different management sites: restored, native, and invaded. This totaled to 75 individual pitfall traps within each management site. The traps were filled with odorless solution and water to break surface tension to allow the arthropods to sink to the bottom when they fell into the traps. The odorless detergent was used so the traps were not considered baited for the arthropods. The traps were left at the study site and collected after one week allowing for ample time for arthropod collection. Once the traps were collected, they were brought back to the Whittier College laboratory for identification. The arthropods were identified by Order using the “Key 4-H Entomology: Key to Common Insect Orders,” handout. Once the data was sorted into excel files by management site and sample point, the class used a program called EstimateS to obtain statistical analysis of the data (species diversity and Shannon-Weiner diversity index ). EstimateS allowed the class to standardize

Example of pit fall trap hole create to capture arthropods

Introduction:

Invaded Site exhibits greater Species Diversity andAbundance of Arthropods than Native and Restored Sites

Stephanie Alcala Department of Biological Sciences and Environmental Science

ENVS 396 Integrated Research MethodsProfessor Mbora

Whittier College, Whittier, California

Zuma canyon, Santa Monica Mountains National Recreation Area (Study Site)

Methods:

Results:

References:Burger, J., Redak, R., Allen, E., Rotenberry, J., and Allen, M. 2003. Restoring Arthropod Communities in Coastal Sage Scrub. Conservation Biology 17: 460-467 Litt, Andrea, Cord, Erin, Fulbright, Timothy, and Schuster, Greta. 2014. Effects of Invasive Plants on Arthropods. Conservation Biology 28 : 1532-1549 Magoba, Rembu and Samways, Michael. 2011. Comparative Footprint of Alien, Agricultural and Restored Vegetation on Surface-Active Arthropods. Biological Invations 14 : 165-177

native, measuring at approximately 13. Thus, invaded has a significant difference in species richness compared to both restored and native. Restored was the site that had the most varied species richness. While invaded seemed to have all of their sample sites measuring close to the mean of 13, however the invaded site has three outliers, restored only has one. Figure 3 exhibits the Diversity of each sample site. Diversity was

Restored Sample Site

Restored Native Invaded

Restored 1 0.385 0.467

Native 0.385 1 0.571

Invaded 0.467 0.571 1

Table 1: Exhibits the percentage (in decimals) of shared Orders found

within each site.

Arthropods are one of the most diverse species on the plant. They drive many community and ecosystem processes. Although a plethora of factors affects species richness and abundance within habitats, availability of resources, competition, species interactions, and soil, affect species richness and affluence of arthropods. While vegetation cover does not directly affect an arthropod population, it does provide them with shelter and food, which directly correlate with succession. Litt et al states that, invaded plants typically result in a reduction in the abundance and diversity of arthropods due to a loss of specific plants for food and shelter. Native arthropods may be unable to adapt or recognize invaded plants as a means of food or habitat (Litt et al, 2014). This may result in a reduction of diversity and abundance. Thus, it is predicted that native plants should promote more diversity and abundance due to arthropods heavy reliance on plants both directly and indirectly for food and refuge (Burger et al, 2003). It is hypothesized that there will be greater species richness as well as species diversity within native management site in comparison to invaded management site due to arthropod reliance on vegetation as a main source of resources. Furthermore, in a recent study it was concluded that although restored and native management areas usually exhibit different characteristics regarding soil moisture and litter depth, species richness and abundance of arthropods were not affected (Magoba and Samways, 2011). Thus, I propose that the native and restored management sires will not exhibit significant differences of sampled arthropod species as well as overall species richness.

the number of individuals sampled and the sampling effort among thetransects to allow for a larger sampling size to reliably reflect the population mean within the management sites. The Order of species found within all three management sites was analyzed using the Jaccard Classic to examine the connections of the different sites. The data was then further analyzed and presented using the statistical programming software R.

The number of individual arthropods sampled within a management site was greatest within the invaded site. The average number of individuals found within each sample site for invaded was roughly 2,400 individuals (Figure 1). While the amount of individuals found within restored and native

measuring at 38.5%. The 1’s on the graph exhibit the shared species within the same site, which explains the three 1’s on Table 1. Restored and Native both exhibited similar species richness means measuring at about 10 and 10.2, respectively (Figure 2). The invaded site has an overall greater species richness than both restored and

Figure 1: Number of Individual Arthropods Found within each site

Figure 2: Species richness of arthropods calculated for each site

Figure 3: Shannon Weaver Diversity Index of arthropods calculated for each site

sites were similar, with restored having a mean of about 1,000 individuals species within each site and native having roughly 900. Figure 1 was graphed using data compiled in EstimateS, which extrapolated the data set, allowing each site to consist of 15 samples of 5 pitfall traps each. This totaled to 75 pit fall traps for every site.

The two management sites that had the most shared species were Invaded and Native with 57.1% shared species (Table 1). Species were classified by Order. Native and Restored had the least common species found within their sites,

invaded management site. Additionally, my results support my hypothesis that native and restored sites will not exhibit significant differences of species richness.

measured using the Shannon Weaver Diversity Index. The native expressed the largest diversity between the three sites. Conversely, the restored site and the invaded site exhibited similar diversity patterns. My results fail to support my hypothesis that there will be greater species richness within the native site as well as my hypothesis that native and restored sites will not exhibit significant differences of shared sampled arthropod species. However my results support my hypothesis that the native site will have greater diversity than the