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HB 2018-Survival of Amer Beech
- 1. SURVIVAL OF AMERICAN BEECH AND SUGAR MAPLE GERMINANTS KATHRYN BAZANY ADAM WILD, NAT CLEAVITT, RUTH YANAI, ALEX RICE, ALEX YOUNG
- 2. AMERICAN BEECH SUGAR MAPLE
- 3. AGENTS OF MORTALITY INSECT HERBIVORY SAP FEEDERS FUNGUS
- 4. OBJECTIVES To determine how treatment (Control, N, P, N+P, Ca) affects sugar maple and beech germinant density and To determine how treatment affects the frequency of agents of mortality
- 5. HYPOTHESES Beech and sugar maple germinant density will vary with treatment Frequency of insect herbivory and sap feeding will be higher in plots with N and P addition Germinants with higher foliar N and P will be more desirable to herbivores and sap feeders
- 6. EXPERIMENTAL DESIGN • 10 (1 m² ) germinant plots per treatment (C, N, P, N+P, and Ca) • 3 old stands in Bartlett • 1 old stand in Hubbard Brook and 1 old stand in Jeffers Brook TREATMENT PLOT Germinant plots
- 8. GERMINANT DENSITY Sugar Maple: Kruskal-Wallis chi-squared = 2.1984 df = 4, p-value = 0.6993 American Beech: Kruskal-Wallis chi-squared = 1.2713, df = 4, p-value = 0.8662 0 20 40 60 80 100 120 C N P NP C N P NP Ca C N P NP C N P NP C N P NP Ca C7 C8 C9 HBO JBO Germinantsperm² Treatment Stand Sugar Maple American Beech
- 9. INSECT HERBIVORY PROPORTIONAFFECTED BEECH SUGAR MAPLE PROPORTIONAFFECTED PROPORTIONAFFECTED
- 11. FUTURE DIRECTIONS • Clearer trends may emerge: – With additional rounds of data collection – If basal area for each species is treated as a covariate for germinant density • By tracking individuals over time we hope to: – Determine which agents are most strongly linked to germinant mortality – Examine correlations between traits like leaf size and germinant survival
Editor's Notes
- Thank you Ruth
- I’m focusing on the germinants of two species, american beech and sugar maple. As Adam explained earlier, 2017 was a mast year, meaning that this is a good year to study germinants as there are more of them. Like most trees, beech and sugar maple produce a lot of offspring and many of them will die in the first season.
- So what is killing all of the germinants? For this study I will be looking at agents of mortality such as (click) insect herbivory. This is a picture of a beech germinant that has been partially eaten by caterpillars. (click) sap feeders, which are insects that drain the fluids from plants. The top image is a sugar maple germinant that has been impacted by thrips, and the bottom image is a beech germinant that has wooly aphids. (click) Fungi kill a lot of germinants in most years. This is an image of root rot. But this has been a dry year, so I haven’t seen much of this. That’s why I’m focusing on insect herbivory and sap feeders.
- My objectives are to determine how nutrient addition treatment affects sugar maple and beech germinant density, and the frequency of the agents of mortality I mentioned on the previous slide.
- I hypothesized that beech and sugar maple germinant density would vary with treatment and that the frequency of insect herbivory and sap feeding would be higher in plots with N and P addition. I made this prediction because germinants with higher foliar Nitrogen and phosphorus will be more desirable to herbivores and sap feeders
- 10 m squared germinant plots were established in each treatment plot in these locations in the 3 old stands in the bartlett experimental forest, 1 old stand in hubbard brook, 1 old stand in jeffers brook.
- At each germinant plot, I am counting total germinants, tagging up to 10 individuals of each species, and determining leaf size, % of damaged tissue, and recording evidence of insect herbivory and sap feeding on those individuals.
- This graph shows germinant density per treatment and stand. Sugar maple is in orange and beech is in green. The bars show standard deviation. Stand variability was high, and does seem to correlate with the basal area of the species. Jeffers brook on the end here has very few beech trees, and we didn’t see any beech germinants, whereas c7 has a lot more beech trees than sugar maples and we see that trend reflected in germinants. It looked like there might be a trend present of more beech in NP plots and more sugar maple in C plots but this trend was not significant based on germinant density alone. Put in tree population or tree basal area: to show that germ population is linked to tree population Make titles bigger! So this is a chart that shows population density of each species in each treatment plot. The y-axis is the average number of germinants found in each meter squared sub-plot. So there are a few interesting things to note in this plot. First, where there are higher densities of sugar maples there are lower densities of american beech and vice versa. For example in C7 there are a lot more beech germinants, and in JBO there are many sugar maples and no american beech. The next thing to notice is that american beech population densities are greater in N and P addition plots than in calcium and control plots, whereas sugar maple is generally higher in the control plots. Additionally, this trend does not occur in JBO where there are no beech germinants. This could suggest that sugar maple populations are negatively impacted by competition with beech germinants. I haven’t run any of the ANOVA’s yet, I’m having difficulties in R, but hopefully soon I will have stats to see if these visually observed trends are significant. And if Adam is able to get any seed production data I could see how closely seed production and germinant population are correlated.
- These charts show the proportion of beech and sugar maple germinants impacted by insect herbivory. I ran a randomized block anova and found that the proportion of both species affected by insect herbivory varied by stand but not by treatment.
- When looking at the proportion of germinants impacted by sapfeeders. I found that a greater proportion of beech germinants were affected in plots with added phosphorus. Again I found that the proportion of germinants impacted by sap feeders for both species varied by stand.
- So what comes next? Well I’m hoping that trends will continue to emerge when I add more rounds of data collection. The data in my presentation only represents the first round of data. I’m also planning on adding basal area data for each species as a covariate in order to more accurately examine germinant density data. Additionally, by revisiting tagged individuals over time I hope I’ll be able to determine which agents are most strongly linked to germinant mortality and to examine correlations between traits like leaf size and germinant survival.
- Any questions or recommendations?