Comparison of the abundance, diversity, and composition of epiphytic bryophytes on sugar maple trees (Acer saccharum March.) between Central New York and the Adirondack Region

Photo: M. Garmendia/ Species: Porella platyphylla

Miguel Garmendia Z.

M.S. Candidate

Environmental and Forest Biology

College of Environmental Science and Forestry

State University of New York

Final Report on Internship

Edna Bailey Sussman Foundation

December 2014

SUMMARY

The main objective of this research was to compare the abundance, diversity, and species composition of epiphytic bryophytes between Central New York (CNY) and the Adirondacks (ADK). This comparison included the determination of the relationship between the abundance of each species with the climate variables temperature and relative humidity. A survey of epiphytic bryophytes was conducted in three state forests in Central New York (Bear Swamp State Forest, Cuyler Hill State Forest, and Long Pond State Forest), and three wild forest in the Adirondacks (Saranac Lake Wild Forest, Horseshoe Lake Wild Forest, and Jessup River Wild Forest). Additionally, six iButton Temperature & Humidity Loggers were set up for four months (June to October) in each site. In total, 32 species were identified in the study area including, 27 in ADK and 21 in CNY. The percent cover per species was higher in ADK (13.19%) compared to CNY (10.52%). The species composition was different due to the number of species unique for each region and the difference in percent cover of the most abundant species from one region to the other. The most abundant and frequently found species were Anomodon attenuatus, Brachythecium oxycladon, and Plagiomnium ciliare. The temperature was significantly different between regions, on the contrary, humidity was not significantly different. On average, the temperature for CNY was 16.79oC, and 15.10oC for ADK. The average humidity was around 88% for both regions. The species whose abundance had a significant relationship with temperature were Neckera pennata and Ulota crispa. The abundance of N. pennata had a significant negative relationship with temperature, while the abundance of U. crispa had a significant positive relationship with temperature. Although some species showed some slight negative or positive relationships with humidity, none of them were significant.

METHOD

The study area for this research was the upland forests of in Northern and Central New York. Six sites were selected in order to conduct this study. Saranac Lake Wild Forest, Horseshoe Lake Wild Forest, and Jessup River Wild Forest in the Adirondack Region (ADK), and Bear Swamp State Forest, Cuyler Hill State Forest, and Long Pond State Forest in Central New York (CNY). The activity consisted on conducting a survey of epiphytic bryophytes on 30 sugar maple trees per site. The criteria for selecting the trees were (a) the trees must had a ≥ 50 cm diameter at the breast height, (b) ≤ 10o of inclination, (c) had to be at the top of a hill, and (d) had to be far from canopy gaps. Line-intercepts were established on each tree at 10, 20, 50, 100, and 150 cm above the ground, following McGee and Kimmerer (2002), to estimate percent cover of each bryophyte species on each host tree. Temperature and humidity were recorded using iButton Temperature & Humidity Loggers. Six devices were placed on trees in which the survey was conducted at each site. The iButtons were set up from June to October 2014.

The Simpson Diversity Index, Jaccard Coefficient, and Morisita Coefficient were calculated to compare the species composition between both regions. The index and the coefficients were calculated according to procedures and equations described by Magurran (2004). Statistical analysis included descriptive statistics, mean comparison (ANOVA, T-test), correlation (Pearson Coefficient), regression, frequency analysis, and multivariate analysis (Cluster Analysis). A significance level of 0.05 was used in all tests. The normality assumption was assessed with Shapiro-Wilks test.

RESULTS

Comparison of abundance, frequency, and species diversity

The number of species in CNY was 27 and the number of species in ADK was 21. The difference in the number of species was not significant (t=1.55, p>0.20). The percent cover for all species in ADK (13.19±17.01% cover) was higher compare to CNY (10.52±15.33% cover) (t=2.40, p<0.018). The expected number of species calculated with the Chao1 Estimator was the same as the number of observed species for each region (CNY=27 species, ADK=21 species). Therefore, there is little chance of finding new species in subsequent samplings. The structure of the community in terms of equitability (equal distribution of the abundance per species) according to the Simpson Diversity Index was more equitable in CNY (0.94) than in ADK (0.92). The difference between large and small bryophyte mats was higher in ADK. In terms of species composition calculated by the Jaccard Coefficient, both regions were 50% similar. The species composition calculated by the Morisita Coefficient (combining the type of species with the abundance) showed a similarity of 66% for both regions.

The low similarity between both regions according to the Jaccard Coefficient, was a result of the high number of unique species. 11 species were found only in CNY and five species were found only in ADK. The species found only in CNY were Anomodon rostratus, Brachythecium reflexum, Callicladium haldanianum, Dicranum montanum, Entodon cladorrhizans, Callicladium haldanianum, Leskea gracilescens, Plagiomnium cuspidatum, Plagiothecium laetum, Rhynchostegium serrulatum, and Thuidium delicatulum. The species found only in ADK were Rhodobryum ontariense, Dicranum scoparium, Leucodon brachypus, Neckera pennata, and Anomodon rugelii. The absence of one species in one region does not mean that the species in not actually there, it means that it was not found during this survey. Increasing the sampling effort could reveal whether the absence of the species is due to dispersal limitations or if the species is present as a rare species.

The 34% difference in species composition according to the Morisita Coefficient was a result of the difference in abundance per species in each region. The most abundant species in one region were not the most abundant species in the other. For example, only three species (Anomodon attenuatus, Brachythecium oxycladon, and Plagiomnium ciliare) out of nine (>15% cover only) were abundant in both regions. A. attenuatus was the most abundant species in ADK, while Brachythecium salebrosum and Pylaisia selwynii in addition to A. attenuatus were the most abundant species in CNY.

B. oxycladon, Brachythecium sp, Frullania eboracensis, and P. ciliare were found more frequently (frequency defined as the number of trees were the species was observed divided by the total number of trees) in both regions. Porella platyphylla was more frequently observed in ADK, while Platygyrium repens, Ulota crispa, and Dicranum viride in CNY.

Relationship abundance-climate

The temperature in both regions was significantly different (t=-20, p<0.0001). In average, the temperature was higher in CNY (16.79oC) than ADK (15.10oC). The relative humidity did not differ significantly from one region to the other (t=1.05m, p>0.29). The average humidity was around 88% for both regions. The total abundance of bryophytes showed a significant negative correlation with temperature (r=-0.07, p<0.04) and humidity (r=-0.08, p<0.02). The species were grouped according to the variables temperature and humidity separately using cluster analysis. Four group were defined in the temperature's cluster (Figure 1).

Figure 1. Cluster analysis grouping the species according to the variable temperature using the Euclidea distance and the Ward Method. Four groups were defined and named 1, 2, 3, and 4 from top to bottom.

An analysis of variance was conducted to test whether the groups differed in term of the temperature values to which each one was associated. As a result, each group was associated with different temperature values (F=70.99, p<0.0001). The species in Group 2 were associated with the highest temperature (Table 1), while the species in Group 3 were found in places where temperature was lower. Group 1 and 4 were associated with middle temperature values. The relationship between the species abundance and the temperature was significant only in Group 2 and Group 3 (Table 1). The species abundance in Group 2 (R2= 0.21) showed a positive relationship with temperature, while the species abundance in Group 3 (R2= 0.47) showed a negative relationship with temperature (Table 1).

Correlation analysis were apply to Group 2 and Group 3 in order to determine the specific species which abundance were corrlated with temperature. As a result, for Group 2 the abundance of U. crispa had a significant positive relationship with temperature (r=0.35, p<0.03; R2= 0.74). The remaining species in Group 2 had not significant relationship with temperature. For Group 3 the abundance of N. pennata had a significant negative relationship with temperature (r=-0.60, p<0.0001; R2= 0.50). The remaining species in Group 3 had not significant relationship.

Table 1. Mean temperature and humidity to which each group was associated as a result of the cluster analysis. Additionally, Pearson Correlation Coefficient for the relationships Cover-Temperature, and Cover-Humidity per group.

Group / Temperature / Humidity
Mean temperature oC / Correlation with abundance / Mean humidity % / Correlation with abundance
Group 1 / 16.23 / r=-0.07, p>0.27 / 90.48 / r=0.58, p>0.43
Group 2 / 16.72 / r=0.40, p<6.0E-4 / 98.15 / r=0.05, p>0.65
Group 3 / 15.07 / r=-0.26, p<0.02 / 88.40 / r=-0.07, p>0.11
Group 4 / 15.86 / r=-0.02, p>0.78 / 87.57 / r=-0.06, p>0.48

Four groups were defined using the humidity as a grouping factor (Figure 2). Each group was associated with significant different relative humidity (F=28.85, p<0.0001). The species in Group 2 were associated with the highest humidity values (Table 1), while the species in Group 3 were associated with places where humidity was lower. However, the relationship between the individual species abundance and humidity within each group was not significant for any of them.

Figure 2. Cluster analysis grouping the species according to the variable humidity using the Euclidea distance and the Ward Method. Four groups were defined and named 1, 2, 3, and 4 from top to bottom.

CONCLUSION

There was no significant difference in the number of species for both regions; however, there was for the abundance. The percent cover of epiphytic bryophytes in ADK was higher than CNY.

The species composition was different. The difference was due to the high number of species that were unique for each area. This reduced the composition similarity between regions. Additionally, only A. attenuatus, B. oxycladon, and P. ciliare were abundant and frequently found in both regions. The abundance and frequency of the remaining species varied from region to region.

As expected, temperature was significantly different between regions; however, humidity was not. The non-significant difference in terms of humidity might be a result of the season (Summer) in which the study was conducted.

Two groups of species with contrasting relationship with temperature were determined. In the group associated with high temperature, only the abundance of U. crispa had a significant positive relationship with temperature. On the contrary, in the group associated with low temperature, only the abundance of N. pennata had a significant negative relationship with temperature.

ACKNOWLEDGEMENTS

I would like to acknowledge the Edna Bailey Sussman Foundation, who made this contribution to the science possible. At the same time, I would like to express my gratitude to my major professor Dr. Gregory McGee, and my committee members Dr. Martin Dovciak, and Dr. Robin Kimmerer, thanks for your valuable advices. I want to thank my internship supervisor Dave Sinclair, regional forester at the New York State Department of Environmental Conservation, Division of Lands and Forests, Region 7. This research was partially funded by the Grober Graduate Research Fellowship to whom I extend this acknowledgement. I would like to say thanks to all people who contributed in different ways to this research, especially to Monica Berdugo, Jay Wason III, Veronica González, and Samouel Beguin.

REFERENCES

Magurran, A. E. 2004. Measuring biological diversity. Blackwell Science Ltd., Oxford, UK.

McGee, G. and W. Kimmerer, (2002). Forest age and management effects on epiphytic bryophyte communities in Adirondack northern hardwood forests, New York, U.S.A. Can. J. For. Res. 32: 1562-1576.

Tuba, Z.; N. G. Slack and L. R. Stark. Bryophyte Ecology and Climate Change. Cambridge University Press. 506 pp.

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