Source: UNIVERSITY OF VERMONT submitted to
MOOSE HERBIVORY: A KEYSTONE ECOLOGICAL PROCESS IN THE NORTHERN FOREST
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0216828
Grant No.
(N/A)
Project No.
VTZ00113
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2008
Project End Date
Sep 30, 2011
Grant Year
(N/A)
Project Director
Strong, A.
Recipient Organization
UNIVERSITY OF VERMONT
(N/A)
BURLINGTON,VT 05405
Performing Department
SCHOOL OF NATURAL RESOURCES
Non Technical Summary
The creation of nature reserves is the primary means used by conservation biologists protect biodiversity. However, unless key ecological processes are protected within the reserves, it may be difficult to maintain biodiversity over the long-term. Consumption of woody vegetation by large herbivores such as moose and deer is one such key ecological process. The effects of browsing by moose can have important effects on the species composition of understory vegetation, the structure of saplings and shrubs, and the rate at which carbon is cycled in forested ecosystems. As browsing by moose impacts understory vegetation, their actions can then have indirect effects on other species in forested ecosystems such as understory birds, and rodents. This study is designed to assess the indirect effects of browsing by moose on forest songbirds understory vegetation in a northern hardwood forest. As moose populations are expected to be affected negatively by climate change, there could be the potential for cascading effects through the ecosystem. The research will be conducted at Hubbard Brook Experimental Forest in New Hampshire. The effects of moose on understory plants and birds will be assessed by comparing moose activity, vegetation composition, and the songbird populations at 371 sites in a 7800 acre watershed. These data will allow us to predict how population changes in a large herbivore such as the moose can influence other parts of the forest ecosystem.
Animal Health Component
25%
Research Effort Categories
Basic
75%
Applied
25%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1230613107012%
1230820107012%
1230830107012%
1230850107012%
1360613107012%
1360820107014%
1360830107014%
1360850107012%
Goals / Objectives
This study is designed to quantify the effects of moose herbivory on understory vegetation and bird populations through 1) a spatial analysis of moose activity, vegetation structure, and understory bird populations across a 3160-ha watershed, and 2) an assessment of the effects of moose browsing on the architecture of hobblebush (Viburnum alnifolium), a shrub which is an important driver of habitat quality for understory birds. The goal of this project is to quantify the contribution of this key ecological process, herbivory, to the maintenance of biodiversity in a northeastern temperate forest. The most important outcome from this project will be a better understanding of the ecological role of moose in maintaining biodiversity in the Northern Forests. This will be formalized through a peer-reviewed article in a suitable journal such as Conservation Biology or Forest Ecology and Management. Because moose are important in generating tourism dollars in the Northern Forest and of strong interest to the general public for conservation, a better understanding of their role in ecosystem processes can help generate public support for conservation initiatives, particularly those that influence climate change. Consequently, a more important outlet for the results of this study will be through avenues that are more accessible to the general public. As such, we will work with the Hubbard Brook Research Foundation through their "Science Links" program to create education and outreach material that is more accessible to the public, educators, and policy makers. Although I have described this project as essentially standing alone, there is considerable interest in expanding research at HBEF to include the effects of large herbivores on ecological processes. It is my hope that this research will lead to collaborative proposals that examine the direct and indirect effects of moose experimentally, through the construction of large, permanent exclosures.
Project Methods
The research will be conducted within the Hubbard Brook Experimental Forest (HBEF), in the White Mountains National Forest, Thornton, NH. HBEF is a 3160-ha forested watershed, with the vegetation composed of a contiguous second-growth of northern hardwoods at low elevations, and red spruce (Picea rubens), balsam fir (Abies balsamea), and paper birch (Betula papyrifera) at higher elevations. In 1995, researchers at HBEF initiated a valley-wide survey of vegetation composition and structure at 371 sites across the watershed. In 1999, this project was supplemented by bird and hobblebush censuses at each of the 371 sites. Since initiation, bird censuses have been conducted annually (and will continue for the next four years) and vegetation was most recently resampled in 2005-06. This project will supplement the valley-wide bird and vegetation surveys by quantifying moose activity through surveys of understory browsing and fecal pellet counts. Data will be collected in 10 x 10 m plots centered on each sampling point on each transect. This work will be conducted over the course of two field seasons to assess interannual variation in moose activity with respect to environmental variables (in particular, variation in snow depth). With these data, we will be able to construct a spatially explicit model that will quantify the correlation between moose, shrub structure and species composition, and understory bird density. Due to the correlational nature of the analysis, evaluation of the causal influence of moose will be difficult. Therefore, we will augment the valley-wide surveys with an assessment of the effects of moose browsing on hobblebush architecture. This work will quantify the architecture (e.g., branching pattern, number of leaves, etc.) of hobblebush in 40 stands that have high and low levels of moose browsing (using paired stands of similar size, aspect, and elevation). By comparing the structure of hobblebush in areas with differing levels of browsing pressure, we will be able to quantify the effects on habitat structure for understory birds. These stands will be selected during the first year of the valley-wide sampling. The field data and spatial analyses will provide a quantitative assessment of the indirect effects of moose herbivory on understory bird communities. We will use these data to provide information to both the scientific community through a peer-reviewed publication and to a general audience through the Hubbard Brook Research Foundation and the Hubbard Brook website.

Progress 10/01/08 to 09/30/11

Outputs
OUTPUTS: We conducted three field seasons of data collection at the Hubbard Brook Experimental Forest, part of the White Mountain National Forest in New Hampshire. Six data sets were collected. The first two were designed to assess the spatial distribution of moose activity in the Hubbard Brook Watershed. Browse surveys were conducted at 371 points in the watershed, quantifying availability of shrubs and saplings (by species) and intensity of browse (2009 and 2010). The second survey for moose activity was a spatially explicit assessment of moose scat. Moose scat was sampled along 120 100x1m transects. Transects were surveyed three times during the summer season to assess detection probability (2009 and 2010). Bird surveys (point counts) were conducted at the 371 points three times during late May-early July (2009-2011). We conducted visual surveys for Lepidoptera larvae to assess the effect of moose browse on larval distribution (2010). A krieged map of moose browse and shrub (hobblebush) density based on data collected during the past two summers was created. This map was ground-truthed with five 1-m radius plots in each of four categories (high browse, high shrub density, high browse, low shrub density, low browse, high shrub density, and low browse, low shrub density, 2011). Finally, we quantified moose browse around 40 Black-throated Blue Warbler nests, and at paired random plots within 15 m of each nest (2010 and 2011). All data were entered into databases and proofed. In conjunction with Sarah Thorne (Prospect Mountain High School, New Hampshire), we developed a week-long set of exercises for high school students focusing on moose morphology, energy budgets, diet, moose-plant interaction, plant growth responses, and the scientific method. After vetting with high school students, this will be available for download through the Hubbard Brook Research Foundation website. Presentations were made to a variety of stakeholders including US Fish and Wildlife Service personnel, state foresters, state wildlife biologists, University of Vermont graduate and undergraduate students, and University of Vermont faculty. PARTICIPANTS: Allan Strong - PI - Management of field work and study design for the project and handled logistical aspects of the project. Training/professional development - Provided for one MS student and one field technician on bird and plant identification, and identification of moose browse. Michael McDonald - MS student - Conducted summer field work, entered and proofed field data. Kate Fournier - MS student - Conducted summer field work, entered and proofed field data. Kaitlin Marczi - Field technician - Assisted with bird and moose data collection. Allen Tate - Field technician - Assisted with moose browse and nest site data collection. Kayla Odom - REU student - Conducted Lepidoptera counts and assisted with moose browse and scat data collection. Benjamin Griffith - Field technician - Managed bird point count data collection and entry. Lynn Christenson - Collaborator, Vassar College - Helped with study design and data collection. T. Scott Sillet - Collaborator, Smithsonian Institution Migratory Bird Research Center - Provided housing and funding for bird survey team. Nicholas Rodenhouse - Collaborator, Wellesley College - Provided housing and funding for bird survey team. Sarah Thorne - Collaborator, Prospect Mountain High School - Helped collect field data and developed curriculum for high school students. Hubbard Brook Research Foundation - Collaborator - Will provide platform for downloading educational material developed from the project. TARGET AUDIENCES: The research is designed to provide a more complete understanding of the effects of moose foraging activity on community dynamics in the northern forest. The target audience is the general public, as there is considerable support for moose as a charismatic species, symbolic of the northern forest. However, the role of moose in affecting plant and bird communities is not well understood, and our goal is to help make the public aware of these connections. This has been formalized by 1) curriculum development for high school students, and 2) presentations to wildlife and forest managers in the Northeast. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Data collected to date have been used in to better understand the effects of moose browsing on plant communities and nutrient dynamics at Hubbard Brook. The striking effects of moose browsing activity on Viburnum alnifolium and Abies balsamea has led to greater interest in the effect of this herbivore on community dynamics. There are two key findings from this research that are applicable across forested ecosystems with moderate moose densities. First, plant growth following moose browse is both vigorous and rapid, but not fully compensated for by plants. Consequently, moose browse over multiple years can have direct, negative fitness effects on plants. Second the Black-throated Blue Warbler, an understory-nesting bird species, preferentially selects nest sites in shrubs that are browsed by moose. This appears to be a consequence of the change in growth structure in browsed shrubs that likely increases the amount of concealment in these sites.

Publications

  • Schwenk, W. S., and A. M. Strong. 2011. Contrasting patterns and combined effects of moose and insect herbivory on striped maple (Acer pensylvanicum). Basic and Applied Ecology 12:64-71.


Progress 10/01/09 to 09/30/10

Outputs
OUTPUTS: In 2010, we conducted our second field season of data collection at the Hubbard Brook Experimental Forest, part of the White Mountain National Forest in New Hampshire. Five data sets were collected during the summer. The first two were designed to assess the spatial distribution of moose activity in the Hubbard Brook Watershed. Browse surveys were conducted at 371 points in the watershed, quantifying availability of shrubs and saplings (by species) and intensity of browse. One 1x1 m plot was assessed at each point. The second survey for moose activity was a spatially explicit assessment of moose scat. Moose scat was sampled along 120 100x1m transects. Transects were surveyed three times during the summer season to assess detection probability. Bird surveys (point counts) were conducted at the 371 points three times during late May-early July. All data were entered into databases and proofed. We conducted visual surveys for Lepidoptera larvae to assess the effect of moose browse on larval distribution. Finally, we quantified moose browse around a subset of Black-throated Blue Warbler nests, and at random plots within 15 m of each nest. PARTICIPANTS: Allan Strong - PI - Management of field work and study design for the project and handled logistical aspects of the project. Training/professional development - Provided for one MS student and two field technicians on bird and plant identification, and identification of moose browse. Michael McDonald - MS student - Conducted summer field work, entered and proofed field data. Kaitlin Marczi - Field technician - Assisted with moose browse and scat data collection. Benjamin Griffith - Field technician - Managed bird point count data collection and entry. Kayla Odom - REU student - Conducted Lepidoptera counts and assisted with moose browse and scat data collection. Lynn Christenson - Collaborator, Vassar College - Helped with study design and data collection. T. Scott Sillet - Collaborator, Smithsonian Institution Migratory Bird Research Center - Provided housing and funding for bird survey team. Nicholas Rodenhouse - Collaborator, Wellesley College - Provided housing and funding for bird survey team. TARGET AUDIENCES: The research is designed to provide a more complete understanding of the effects of moose foraging activity on community dynamics in the northern forest. The target audience is the general public, as there is considerable support for moose as a charismatic species, symbolic of the northern forest. However, the role of moose in affecting plant and bird communities is not well understood, and our goal is to help make the public aware of these connections. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Data collected to date have been used in to better understand the effects of moose browsing on plant communities and nutrient dynamics at Hubbard Brook. The striking effects of moose browsing activity on Viburnum alnifolium and Abies balsamea has led to greater interest in the effect of this herbivore on community dynamics. Two additional grant proposals have been submitted (one funded, one not funded) that have built upon this critical ecological process.

Publications

  • Schwenk, W. S., and A. M. Strong. 2011. Contrasting patterns and combined effects of moose and insect herbivory on striped maple (Acer pensylvanicum). Basic and Applied Ecology 12:64-71.


Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: In 2009, we began data collection at the Hubbard Brook Experimental Forest, part of the White Mountain National Forest in New Hampshire. Three data sets were collected during the summer. The first two were designed to assess the spatial distribution of moose activity in the Hubbard Brook Watershed. Browse surveys were conducted at 371 points in the watershed, quantifying availability of shrubs and saplings (by species) and intensity of browse. Eight 1x1 m plots were assessed at each point. The second survey for moose activity was an spatially explicit assessment of moose scat. Moose scat was sampled along 120 100x1m transects. Transects were surveyed three times during the summer season to assess detection probability. Finally, bird surveys (point counts) were conducted at the 371 points three times during late May-early July. All data were entered into databases and proofed. PARTICIPANTS: Allan Strong - PI - Management of field work and study design for the project and handled logistical aspects of the project. Training/professional development - Provided for one MS student and one field technician on bird and plant identification, and identification of moose browse. Kate Fournier - MS student - Conducted summer field work, entered and proofed field data. Kaitlin Marczi - Field technician - Assisted with bird and moose data collection. Benjamin Griffith - Field technician - Managed bird point count data collection and entry. Lynn Christenson - Collaborator, Vassar College - Helped with study design and data collection. T. Scott Sillet - Collaborator, Smithsonian Institution Migratory Bird Research Center - Provided housing and funding for bird survey team. Nicholas Rodenhouse - Collaborator, Wellesley College - Provided housing and funding for bird survey team. TARGET AUDIENCES: The research is designed to provide a more complete understanding of the effects of moose foraging activity on community dynamics in the northern forest. The target audience is the general public, as there is considerable support for moose as a charismatic species, symbolic of the northern forest. However, the role of moose in affecting plant and bird communities is not well understood, and our goal is to help make the public aware of these connections. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Data collected to date have been used in to better understand the effects of moose browsing on plant communities and nutrient dynamics at Hubbard Brook. The striking effects of moose browsing activity on Viburnum alnifolium and Abies balsamea has led to greater interest in the effect of this herbivore on community dynamics. Two additional grant proposals have been submitted (one funded, one in review) that have built upon this critical ecological process.

Publications

  • No publications reported this period