Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Dissertation_Ricart_FINAL_417.pdf (10.1 MB)

ETD Abstract Container

Abstract Header

Drivers of plant diversity and distribution in a northern hardwood forest - interacting effects of biotic and abiotic factors

Ricart, Raleigh Dean
http://rave.ohiolink.edu/etdc/view?acc_num=osu1555258314195712

Abstract Details

2019, Doctor of Philosophy, Ohio State University, Evolution, Ecology and Organismal Biology.
The drivers of plant diversity and community composition are often influenced by deterministic mechanisms, such as existing environmental conditions, including landscape-level topographic features. In addition, evidence suggests that stochastic mechanisms can also play a critical role in plant community assemblage. Therefore, I investigated how diversity and composition are distributed through space in a mid- successional mixed hardwood forest in northern lower Michigan, USA. This region has been heavily influenced by its glacial past, which resulted in geographically and abiotically distinct glacial landforms that have been shown to influence spatial dynamics of forest communities. Vegetation sampling plots (n=87) were established at the University of Michigan Biological Station (UMBS). Vegetation data of the overstory (>9cm dbh), sapling (1.5-9cm dbh) and groundcover (% cover) layers were collected. Abiotic variables, including elevation, pH, and soil nutrients, were collected in a subset of plots (n=40). I conducted various multivariate statistical analyses to assess the difference in plant communities and abiotic condition, including ANOVA, Variation Partitioning, PERMANOVA, NMDS, and RDA. Variation Partitioning results demonstrated that both deterministic and stochastic mechanisms influenced the community composition of all vegetation layers, however the overstory was mostly influenced by stochastic mechanisms, while the sapling and groundcover layers were opposite. ANOVA results showed strong differences in diversity between glacial landforms. Additionally, PERMANOVA and Non-metric Multidimensional Scaling (NMDS) showed strong differences in community composition between the glacial landforms. Redundancy Analysis (RDA) revealed a strong influence of abiotic variables on composition, with the strongest effects coming from elevation and O horizon depth (O_depth). My findings indicate a large influence of glacial landforms on the production and maintenance of local plant diversity and community composition in this area. Plant diversity and composition are also strongly influenced by successional dynamics following a disturbance event. Moreover, spatial and temporal dynamics are interactive, and rates of successional advancement can be variable depending on underlying spatial gradients. I investigated how diversity and composition are distributed through time using the same system and vegetation data described above. However, vegetation sampling plots were censused in 1990 and again in 2015, which allowed for me to track compositional change over a 25-year-period. ANOVA results showed relatively stable levels of species diversity between census periods. In addition, PERMANOVA results revealed very little difference in community composition over the twenty-five-year period. Furthermore, we found no evidence of differences in successional rates between landforms. My findings suggest that successional dynamics may manifest themselves over much longer time periods in these northern biomes. Finally, I tested the effects of competition of Pteridium aquilinum (“bracken” fern) on the growth and survival of two prominent tree seedlings, Pinus strobus and Acer saccharum. Furthermore, I was interested in how above- and belowground competition from bracken varied across a fertility gradient. Twelve plots were established in four bracken-dominated stands at the UMBS. Seedlings of both species were subjected to one of the following treatments: aboveground competition removal, belowground competition removal, above- and belowground competition removal, and control. Each replicate was a split-plot design, where the soil fertility in half of the plot was altered using nitrogen fertilizer. Differences across collected variables were analyzed using ANOVA. Bracken had an overall negative effect on the growth of both seedlings, with significantly lower values for Relative Growth Rate in both shoot and root biomass under full bracken- competition treatments. There was no difference between fertility treatments, suggesting that competitive strategy does not change with increased availability of soil nitrogen. Finally, there was a significant difference between the overall performance of the two species, where P. strobus outperformed A. saccharum across most of the collected variables. This suggests a possible species-specific “filtering effect” of bracken that may have long-term consequences for the composition of future forests in the area.
Peter Curtis (Advisor)
Maria Miriti (Committee Member)
Stephen Hovick (Committee Member)
Luke Wilson (Other)
237 p.
Ecology; Plant Biology
forest; ecology; community; plant; diversity; composition; competition; succession; deterministic; stochastic

Recommended Citations

Citations

  • Ricart, R. D. (2019). Drivers of plant diversity and distribution in a northern hardwood forest - interacting effects of biotic and abiotic factors [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555258314195712

    APA Style (7th edition)

  • Ricart, Raleigh. Drivers of plant diversity and distribution in a northern hardwood forest - interacting effects of biotic and abiotic factors. 2019. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1555258314195712.

    MLA Style (8th edition)

  • Ricart, Raleigh. "Drivers of plant diversity and distribution in a northern hardwood forest - interacting effects of biotic and abiotic factors." Doctoral dissertation, Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555258314195712

    Chicago Manual of Style (17th edition)

osu1555258314195712
322
© 2019, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.