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Lab #7 Growth Characteristics of Amur Honeysuckle

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Lab #7

Growth Characteristics of Amur Honeysuckle (Lonicera maackii)
Amur Honeysuckle (Lonicera maackii) is a highly invasive shrub deliberately introduced from the Amur River region of northeast Asia to multiple locations in the eastern United States beginning in the 1850s (Luken and Thieret 1996). Copious production of red berries, dispersed primarily by birds, has since resulted in fairly rapid range expansion; the species is now “naturalized” in isolated portions of much of the eastern U.S. (Fig. 1) and Canada.

Fig. 1. Distribution of L. maackii in the United States. (

Rapid spread of L. maackii depends on seed survival following consumption by frugivorous birds (Bartuszevige et al. 2006), and appears to be promoted by the presence of ecotones/edge habitat adjacent to woodlots (Hutchinson and Vankat 1998). Seedling establishment and subsequent growth rates are both promoted by landscape fragmentation (Bartuszevige et al. 2006), particularly in woodlots within more urban settings (Luken 1988, Luken and Goessling 1995, Luken et al. 1995, Luken et al. 1997, Borgmann and Rodewald 2005). Changes in plant architecture and biomass allocation during growth have been examined by Luken et al. (1995) and Deering and Vankat (1999).

Rather severe negative impacts of L. maackii on the growth and survival of native herbaceous species and seedlings have been demonstrated in several studies (Gould and Gorchov 2000, Collier and Vankat 2002, Miller and Gorchov 2004). Methods for eradication of L. maackii, and the regeneration of native species following L. maackii eradication (Hartman and McCarthy 2004), are a principal focus of ongoing research in the Gordon Natural Area directed by Dr. Gerry Hertel.

The purpose of this lab is to determine the growth, age structure and biomass allocation of individuals of L. maackii growing in forested vs. more open locations within the WCU Gordon Natural Area (GNA), where the species has become prevalent. The “open” location is a former orchard, abandoned between 1970 and 1980; the forested location is directly adjacent (Fig. 2).

Fig. 2. Aerial photo of study area in 1970 (L) and 2005 (R).

L. maackii is thought to have colonized the area sometime in the 1970s, but whether it arrived first in the wooded area, or in the abandoned orchard, is unknown. Although the species is known to successfully colonize both open and closed habitats, previous work suggests that rates of new stem production, stem mortality, and leaf production per stem may all be influenced by light availability. The dispersion of genets may thus reflect the patchiness of light as well as seed dispersal. Determination of the age of the oldest (usually central stem) will be used to infer the history of establishment by L. maackii in the GNA.

This is a three-part lab. During the first week we will destructively sample several genetic individuals (genets), collecting a range of morphometric data in the field. Teams will age the stems they collected during the following week, and then analyze the data for growth and age properties using Excel during the second lab period.

Field Sampling Procedure (Part 1)

The class will divide into teams, each assigned to one or more genets. The following equipment will be needed in the field:

 hand saws

canopy densiometer

 Spring balances

 Quart baggies for returning stem sections to lab for age determination

Each team is responsible for determining the age, diameter and weight of each stem on the genet(s) chosen for study. Fill out the information in Table 1, except for Stem Age, in the field. Retain Table 1 at the end of the field trip for later age analysis:

Now sever each stem, one at a time, at a distance of 10 cm above its base. The cut should be as nearly transverse (perpendicular to the stem length) as possible. Make a second transverse cut about 2 cm further up the stem, and place the 2-cm plug in a quart baggie with a tag indicating sampling date, genet number and stem number. This will be used next week for age determination. Dead stems should be collected as well for measurement of diameter, but will not be aged. Finally, record the stem weight using a spring scale.

Age Determination (Part 2)

Each team should meet with me outside of class time during the week between the fieldwork and indoor data analysis.

Dip one end of the plug in a Stender dish of phloroglucinol for 30 seconds (do not over-stain the plug). Blot once on a piece of paper towel, then dip the end into a second Stender dish of concentrated HCl (corrosive!! be careful not to spill or drip, and notify the boss immediately in the event of a mishap). Again blot dry on a piece of paper towel, then rinse in DI water. Place the plug on a piece of Sharpie-labeled towel, and allow to dry prior to the next lab.
Data Analyses (Part 3)

In SSN381, use sand paper to create a fine surface for viewing the growth rings. Dissecting scopes are available to enhance the image. “Rings” are produced by the alternation of large xylem vessels (produced in the growing season) with smaller xylem vessels produced during the winter. Count the number of rings to determine the age, with 0 = New stem produced this year, 1 = 1 year old (produced last year), etc. See Figure 2 for an example. Once all plugs from your team have been aged (and helping out other teams if necessary), head to the computer lab.

Fig. 2. Stained cross section of L. maackii stem. What is the age of this stem?
In the computer lab you will work with other members of your team to analyze your own data, and will further share results for each genet on the White Board for use by the entire class. Begin by downloading (do not attempt to perform your analyses on D2L!) and opening the Excel workbook “Amur Honeysuckle Data”. The workbook has two spreadsheets, containing templates for “Team Data” and “Class Data”. Transfer all data from Table 1 into the spreadsheet “Team Data” (if you have more than 1 genet, create multiple Team Data sheets with one sheet for each). The age of the oldest stem is assumed to be the age of the genet (this may not be strictly correct if the oldest stem has died). Add this value to cell C23 of the spreadsheet.

In addition to the columns for Stem Number, Stem diameter, Stem Weight, and Stem Age in columns A-D (in which you need to add your data), notice that column E automatically calculates the log10(stem diameter). Two additional columns contain calculations of what the biomass of stem and branches (combined) should be for a stem with the diameter you entered for a plant growing in the open, with high light (HL) conditions (column F) or under a closed canopy with low-light (LL) conditions (Column G). These are estimates based on a study by Luken (1988; Table 1) of L. maackii in Ohio.

In row 23 use the SUM function to obtain the total weight of all stems (in D23), and the predicted total weight of the stems if the genet had grown under high light (HL) vs. low light (LL) based on Luken (1988) (in cells F23 and G23). Add the summary data for each genet to the table in “Class Data” and on the white board for general class use.

Return to the “Team Data” for your first genet. Highlight the data for Age and (immediately to the right) stem weight including the column titles Age (yr) and Stem Wt (g). Insert an XY Scatterplot below the template. Clean up axis titles, and save the spreadsheet with graph for your write-up. Repeat this procedure for any other genets evaluated by your team.

Now click on the “Class Data” spreadsheet. Highlight the first 4 columns including column titles (for the Orchard data), and pull down under Insert to XY Scatterplot. Customize the resulting graph with appropriate axis titles, and label the graph Orchard. Similarly, create a graph of the Woodlot data, and again customize the titles. Save these two graphs for your write-up.

Answer the following questions.

  1. Evaluate the age structure of each genet sampled by your team. Where was it found (orchard or woods), and when (what year) did it become established in the area? Summarize its general growth trajectory. (e.g., How rapidly were additional ramets added to the genet? Did any stems die? ). Append the graph of stem weight vs. age of the stems for each genet.

  2. Recognizing that Luken’s (1988) data excluded leaves, and that his study described very open vs. closed-canopy habitats in Kentucky (unlike the current dataset describing growth under varying light conditions in Pennsylvania, recorded at the very end of the growing season, and including leaves), how closely are the class data related to Luken’s previous work? Is there evidence that genets that colonized the orchard may have benefitted from the initial growth conditions it provided? Discuss, and append the graphs for both the Orchard and Woodlot data.

Literature Cited
Bartuszevige, A.M., and D.L. Gorchov. 2006. Avian seed dispersal of an invasive shrub. Biological Invasions 8:1013-1022.

Bartuszevige, A.M., Gorchov, D.L., and L. Raab. 2006. The relative importance of landscape and community features in the invasion of an exotic shrub in a fragmented landscape. Ecography 29:213-222.

Borgmann, K.L., and A.D. Rodewald. 2005. Forest restoration in urganizing landscapes: interactions between land uses and exotic shrubs. Restoration Ecology 13:334-340.

Collier, M.H., and J.L. Vankat. 2002. Diminished plant richness and abundance below Lonicera maackii, an invasive shrub. Am. Midl. Natur. 147:60-71.

Deering, R.H., and J.L. Vankat. 1999. Forest colonization and developmental growth of the invasive shrub Lonicera maackii. Am. Midl. Natur. 141:43-50.

Gould, A.M.A., and D.L. Gorchov. 2000. Effects of the exotic invasive shrub Lonicera maackii on the survival and fecundity of three species of native annuals. Am. Midl. Nat. 144:36-50.

Hartman, K.M., and B.C. McCarthy. 2004. Restoration of a forest understory after the removal of an invasive shrub, Amur Honeysuckle (Lonicera maackii). Restoration Ecology 12:154-165.

Hutchinson, T.F., and J.L. Vankat. 1998. Landscape structure and spread of the exotic shrub Lonicera maackii (Amur honeysuckle) in southwestern Ohio forests. Am. Midl. Natur. 139:383-390.

Luken, J.O. 1988. Population structure and biomass allocation of the naturalized shrub Lonicera maackii (Rupr.) Maxim. in forest and open habitats. Am. Midl. Natur. 119:258-267.

Luken, J.O. 1988. Population structure and biomass allocation of the naturalized shrub Lonicera maackii (Rupr.) Maxim. in forest and open habitats. Amer. Midl. Natur. 11:258-267.

Luken, J.O., and N. Goessling. 1995. Seedling distribution and potential persistence of the exotic shrub Lonicera maackii in fragmented forests. Am. Midl. Natur. 133:124-130.

Luken, J.O., and D.T. Mattimiro. 1991. Habitat-specific resilience of the invasive shrub Amur Honeysuckle (Lonicera maackii) during repeated clipping. Ecol. Applic. 1:104-109.

Luken, J.O., and J.W. Thieret. 1996. Amur Honeysuckle, its fall from grace. Bioscience 46:18-24.

Luken, J.O., Kuddes, L.M., Tholemeier, T.C., and D.M. Haller. 1997. Comparative responses of Lonicera maackii (Amur Honeysuckle) and Lindera benzoin (Spicebush) to increased light. Am. Midl. Natur. 138:331-343.

Luken, J.O., Tholemeier, T.C., Kunkel, B.A., and L.M. Kuddes. 1995. Branch architecture plasticity of Amur Honeysuckle (Lonicera maackii) Rupr. (Herder): Initial response in extreme light environments. Bull. Torrey Botan. Club 122:190-195.

Miller, K.E., and D.L. Gorchov. 2004. The invasive shrub, Lonicera maackii, reduces growth and fecundity of perennial forest herbs. Oecologia 139:359-375.

Table 1. Field/lab datasheet for sampling a genet of L. maackii.

Date: ___________

Woodlot (W) or Orchard (O) ________

Genet Number: ____

Genet Age: ___

Tot. No. stems: ____

No. dead stems __

% dead stems: ___

Canopy % Cover: ____

Canopy Code (O/C): __

Stem Number

Stem diam (cm)

Stem Wt (g)

Stem Age (yr)

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