Source: UNIVERSITY OF GUAM UOG STATION submitted to NRP
ASSESSING POPULATIONS OF NATIVE TREE SNAILS (PARTULIDAE PILSBRY, 1900) AND FOREST HABITAT REQUIREMENTS IN THE MARIANA ISLANDS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
1018098
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Nov 28, 2018
Project End Date
Sep 30, 2022
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UNIVERSITY OF GUAM UOG STATION
(N/A)
MANGILAO,GU 96913
Performing Department
Experiment Station
Non Technical Summary
The native tree snails of Guam and the other Mariana islands are disappearing quickly, because of destruction of their forest homes and the presence of alien predators. There are six species of tree snails known from the Mariana islands; three of these are now likely extinct. Guam is home to four species, but one has gone extinct, two species have almost disappeared, and only one, the Guam Tree Snail, remains somewhat common. On other islands, tree snail colonies are rapidly declining and have disappeared completely from some locations. Damage to the tropical forests of the islands by wild pigs, deer, and humans have changed forests, often changing the soil and plant species in limestone forests. Although brown tree snakes don't pose a threat to these snails, several other kinds of alien animals are attacking native tree snail, including a flatworm and ants. Tree snails play an important role in forest communities by breaking down decaying plant matter and removing microorganisms from leaves. Efforts to restore native forests in the region will benefit from the presence of indigenous tree snails.Although there are previous studies on Mariana tree snails, most are out of date or incomplete.My previous McIntire-Stennis funding helped map and estimate populations across Guam, and the current project will expand those surveys. We have to go back to 1925 for the last published study on the basic biology of these snails! Very little is known about the life histories of these snails, including habitat requirements and diet. For this proposed research, we will expand surveys to of tree snail populations on Guam and other Mariana islands. We will characterize habitat parameters for each species and assay fecal material to assess diet. We will also begin development of captive rearing methods where possible. Our results will help wildlife agencies make decisions about what actions to take to protect these species and their forest habitats. It will identify trouble spots, and good locations that for relocating snails that are under threat. This research will also lay the foundation for future studies of tree snails and provide information to the general public about what they can do to help.
Animal Health Component
5%
Research Effort Categories
Basic
80%
Applied
5%
Developmental
15%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
13608301060100%
Knowledge Area
136 - Conservation of Biological Diversity;

Subject Of Investigation
0830 - Wild animals;

Field Of Science
1060 - Biology (whole systems);
Goals / Objectives
The goals of the proposed study are to:1) continue to identify and map populations of partulid snails on Guam, Rota, Saipan, and other accessible Mariana Islands.2) characterize the physical and biological features of habitats where tree snails occur.3) examine fecal samples of all three native species of snails to determine dietary composition.4) develop, in collaboration with qualified zoos in the US and UK, captive rearing protocols for partulid snails that might be used to save local tree snail populations that are at risk.
Project Methods
MethodologyPopulation SurveysPopulation surveys will be conducted to identify the location of extant partulids, and the size of each population. On Guam, we have already identified over 60 populations of partulids across the island. Survey work on Guam will be to estimate population sizes (and extents) at those sites, and to search for new populations in areas not yet visited. For population surveys, a team of 2-4 people conduct walking transects in in forested areas previously known to have partulids, and those identified as likely habitats for tree snails. Likely habitats are typically forested areas relatively broad-leaved trees that form a dense canopy over shorter vegetation, particularly in areas with shallow water tables and/or standing fresh water (Smith et al, 2008). Team members will fan out and visually survey the vegetation for snails. When any snails are located, gps coordinates will be recorded and team members will conduct searches to determine the extent of the populations. Later, intensive, timed searches of known populations will be conducted in the manner of Smith et al. (2008). A quadrat line with a diameter of eight m (50 m2) centered on the trunk of the home plant will be searched for one person-hour, noting the species of snail found, number of individuals found, and what plant or substrate they are found on. One person-hour will be divided by the number of individuals searching, to keep a standard search effort to infer population size. For example, if four individuals are on the team, each will occupy a quarter of the quadrat and search for 15 minutes. If the number of snails is very large in a location, team members may perform a sweep of a habitat, tallying the number and recording the GPS location of clusters of snails. Maps and densities of snails at each site will be generated. Geolocation data will be used for spatial analysis and comparisons to previous location data for temporal comparisons where possible.Habitat SurveysFor populations of rarer partulids (P. gibba&S. fragilis), we will characterize vegetation, soil composition, leaf litter, canopy and seasonal temperature & humidity levels. Vegetation will be characterized by recording presence of plant species in habitats supporting snails and calculating species richness. Soil composition will be measured with PSA (particle size analysis) of samples from standardized quadrats in the field. Leaf litter will be collected from soil composition quadrats and dried to estimate dry weight of leaf litter. Canopy cover will be measured using the moosehorn method to generate mean % cover data for different habitats. Temperature and humidity will be measured using Kestral Drop data loggers to estimate daily and seasonal variations. Data will be compared between different locations using multivariate statistics where appropriate. Evidence of predation (and occurrence of Manokwari flatworms) will also be noted.Dietary AnalysisFecal strands of all three species of partulid snail will be collected in situ from leaves with individual partulid snails, and placed in separate plastic vials. Fecal samples will be moistened, dissolved in water, and examined in suspension under a compound microscope to identify material that has passed through their guts. Dietary diversity indices will be calculated for each species, and between different populations of the same species where possible.Captive RearingA consortium of Zoos in the UK have maintained colonies of partulid snails (includingP. gibba) from around the Pacific for several years. A few zoos in the US (including the St. Louis Zoo), have expressed interest in working with snails from the Marianas. I will work with these entities to improve and develop protocols for captive rearing of our native species, and visit facilities with active captive rearing programs. The state of Hawaii also has a facility for their Oahu snails that may serve as a model we can use on Guam. Methods will be developed as a contingency plan that may be used in the future.?Collaboration and AssistancePlant identifications will be done with the assistance of Dr. James McConnell (Guam Plant Extinction Program, WPTRC, University of Guam) and Dr. Frank Camacho (Biology Program, CNAS, University of Guam). Identification of arthropod predators (e.g., ants) will be done by specialists at the University of Guam, where needed. My collaborator on other partulid projects, Dr. Alex Kerr (UOG Marine Lab) has agreed to participate in any survey work and provide other technical assistance where needed. David Sischo (Snail Extinction Prevention Program, Hawaii State DLNR) will also collaborate for snail surveys when possible. Brent Tibbatts (Guam DAWR) has also agreed to facilitate surveys on Guam when possible.

Progress 10/01/20 to 09/30/21

Outputs
Target Audience: Several groups and entities benefited from the work supported by this McIntire-Stennis Grant. Government agencies include the U.S. Fish and Wildlife Service, Guam Division of Aquatic and Wildlife Resources, U.S. National Park Service, USDA APHIS, and the Joint Region Marianas (JRM) of the Department of Defense. Non-agency targets include members of the scientific community associated with the University of Guam, environmental consulting firms, general public,undergraduate and graduate students. Accredited zoos with partulid snail rearing programs can also be included as beneficiaries this year. Changes/Problems: The biggest disruption in FY21 was the continued impact of the Covid19 pandemic. Personal interactions were restricted, and transportation resources to field sites became limited, due to single occuppancy requirements in vehicles. DoD funded projects were allowed to continue and had priority, though they were slowed considerably. The university allowed limitedundergraduate and graduate student interactions with faculty. The surge due to the Delta variant forced most instructional facutly to return to distance learning methods. This took time away from the McIntire Stennis project efforts. There were also some difficulties in procurement that affected my ability to use funding. What opportunities for training and professional development has the project provided? This project has provided several opportunities for training and professional development, primarily to students at the University of Guam and staff of local and federal government agencies, potential collaborators at US Zoosas well as myself. One undergraduate in the UOG Biology program helped with fieldwork for photographic mark-recapture studies, as part of her directed research project during the early part of the FY. A second undergraduate processed mark-recapture photos as a part of her work study job in late FY.These students had an opportunity to learn more about the biology of tree snails, plant identification, field methodology, and limestone forest ecology. These experiences for students are important, as they provided practical training in field research, and exposure to field biology and conservation. Collaborations with various government agencies also provided opportunities for training and personal development. I continued to workclosely with the Department of Defense (DoD) to provide training for biomonitors and CIS personnel working on various CESU grands. The USFWS also established a monthly tree snail discussion forum for various stakeholders (DoD, CNMI DFW, Gov Guam) concerned with endangered snails. I participated regularly in this informal group via teleconference presenations and discussion.? How have the results been disseminated to communities of interest?As above, I took part in a montly discussion group with regional stakeholders on tree snail conservation. I produced a video presentation for US zoos to introduce them to our endangered tree snails and the challenges involved with their conservation. The video was designed to spur their interest for future collaboration in captive rearing. I wrote one technical report to summarize the obsevations and notes I made of the captive rearing systems at three US Zoos and shared with stakeholders. What do you plan to do during the next reporting period to accomplish the goals? I will continue locating and mapping endangered tree snail populations locally and in the CNMI (where possible). We will start measuring physical environmental variables of representative tree snail populations as part of my graduate student's research in the coming months. I will continue conversations with personnel of US zoos with partulid snail rearing programs for future collaborations. With the local USFWS, werecently established a discussion group of non-DoD entities to move plans for captive rearing forward. I will apply for permits with the St. Louis Zoo for this purpose.

Impacts
What was accomplished under these goals? The Covid 19 pandemic further restricted research activities in 2021 and set back progress in this project. Accomplishments were limited, but important for goal #4. 1) Continue to identify and map populations of partulid snails on Guam, Rota, Saipan, and other accessible Mariana Islands. I located or confirmed populations ofP. radiolata in two new locations (Agat, Tanguisson) and confirmed continued presence ofS. fragilisandP. radiolataat Sella Bay with three brief surveys. I also documented and reported thedestruction of vegetation at the Sella Bay Lookout, which containedP. radiolatato USFWS and Guam's DAWR. I also continued development of photo mark recapture survey methods for partulid snails and collaborated with Scott Vogt at Andersen Air Force Base environmental services to use program Mark and other analysis tools to analyze the mark recapture data. Goals 2,3: I was unable to make progress on these goal, because of Covid19 restrictions for graduate students and faculty. However, USFWS issued a permit to me to work directly with protected snails for this and other projects, allowing me to handle snails directly. Goal 4:develop, in collaboration with qualified zoos in the US and UK, captive rearing protocols for partulid snails that might be used to save local tree snail populations that are at risk. I visitedthree zoos on the US Mainland to assess their captive rearing programs forPartula nodosaand establish relationships for future rearing work with local partulid species. I traveled in the last two weeks of July 2021. I first flew to St. Louis Zoo, who manage thePartula nodosa captive rearingprogram for all US zoos under Glenn Frei. I oserved and recorded their rearing setup and discussed possible applications towards our native species. During the second week of the trip, I visited the Akron and Detroit Zoos to see theirPartularearing systems for comparitive purposes. I wrote a detailed report of the trip, including many photos and will publish as a UOG technical report. Each Zoo has it's own system, but the St. Louis Zoo is the most successful and organized. I also established lines of communication with the St. Louis Zoo staff and plans to proceed with captive rearing efforts if permits can be obtained from USFWS.

Publications


    Progress 10/01/19 to 09/30/20

    Outputs
    Target Audience: Several groups and entities benefited from the work supported by this McIntire-Stennis Grant. Government agencies include the U.S. Fish and Wildlife Service, Guam Division of Aquatic and Wildlife Resources, U.S. National Park Service, USDA APHIS, and the Joint Region Marianas (JRM) of the Department of Defense. Non-agency targets include members of the scientific community associated with the University of Guam, environmental consulting firms, and some of the general public, including undergraduate and graduate students. Changes/Problems:The biggest disruption in FY20 was the Covid19 pandemic, which started its impact in early March here. Personal interactions were restricted, and transportation resources to field sites became limited, due to single occuppancy requirements in vehicles. DoD funded projects were allowed to continue and had priority, though they were slowed considerably.The university discouraged undergraduate and graduate student interactions with faculty.Increased child care demands kept myself and others at home, rather than in the field. Although there was a moderate relaxationof restrictions in June, a wave of new CV19 cases in August brough back tight restrictions. A planned visit to captive rearing facilties at the St. Louis Zoo for Spring 2021 was cancelled in advance, and pushed to 2022. It's likely other goals will also have to be pushed back an additional year. What opportunities for training and professional development has the project provided? This project has provided several opportunities for training and professional development, primarily to students at the University of Guam and staff of local and federal government agencies, as well as for the PIOne undergraduate in the UOG Biology program helped with fieldwork for photographic mark-recapture studies, as part of her directed research project. This studenthad an opportunity to learn more about the biology of tree snails, plant identification, field methodology, and limestone forest ecology. These experiences for students are important, as they provided practical training in field research, and exposure to field biology and conservation. One MS Biology student in the lab submitted her proposal during FY20, but was unable to progress on the portions of her project involved with this grant. Collaborations with various government agencies also provided opportunities for training and personal development. I worked closely with the Department of Defense (DoD) to polish methods and provide a visual training opportunties to survey snails. These skills will be important for DoD contractors and personnel in identifying endangered tree snails while working in forests on DoD installations. We also completed a field guide for native tree snails with funding from DoD and USFWS for it's development and prinitng. Ialso liased with the CNMI's invertebrate biologist (Bronson Curry) and discussed future collaborations and shared data, as well as DAWR wildlife biologists. How have the results been disseminated to communities of interest?The mark-recapture method we developed was used for a Navyfunded CESU project to assess tree snail populations in 2020 and another US Air Force funded CESU project at a different location. We continue to refine the technique and develop best practices for data analysses with technical representatives for both the Air Force and Navy. I also trained UOG field biologists from CIS (Center for Island Sustainability) and GPEPP (Guam Plant Extinction Protection Program) in snail survey techniques, to increase the pool of trained biologists for current and future projects. What do you plan to do during the next reporting period to accomplish the goals?If the pandemic situation improves, our field work projects can return to a normal level. We canstart measuring physical environmental variables of representative tree snail populations as part of a graduate student's research. And we canlook for a student to do fecal analysis and continue preparations with US zoos with partulid snail rearing programs for future collaborations.

    Impacts
    What was accomplished under these goals? The Covid19 pandemic restricted research activities in 2020 and set back progress in this project. Accomplishments were limited. 1) Continue to identify and map populations of partulid snails on Guam, Rota, Saipan, and other accessible Mariana Islands. We located mapped several new populations ofP. radiolata (Chalan Pago, Sinajana, Sasa Valley, Anao)and two population sites forSamoana fragilis(Anou & Santa Rita)mostly as parts of other projects. We did develop a technique for photographic mark-recapture populations estimates, and tested it in another funded project. This technique is a non-invasive method that does notrequire physcally marking snails. Instead, photographs from standard orientations of snails (withing a defined area) are taken with a digital camera, then uploaded into a software program called, "Hotspotter". Hotspotter then compares photos of snails taken on different dates and lists the top visual matches. This technique appears effective for all three of Guam's partulid snails. Goals 2, 3, 4: We were unable to make progress on this goal, because ofCovid19restrictions for graduate students and faculty. However, USFWS is nearly ready to issue a permit to me for to work directly with protected snails - which will allow us to handle snails directly in the future.

    Publications


      Progress 11/28/18 to 09/30/19

      Outputs
      Target Audience: Several groups and entities benefitted from the work supported by this McIntire-Stennis Grant. Government agencies include the U.S. Fish and Wildlife Service, Guam Division of Aquatic and Wildlife Resources, U.S. National Park Service, USDA APHIS, andthe Joint Region Marianas (JRM) of the Department of Defense. Non-agency targets include members of the scientific community associated with the University of Guam, a few environmental consulting firms, and some of the general public, including undergraduate and graduate students. Changes/Problems:No major changes at this stage. Continued problems with UOG procurement office affected access to needed equipment. What opportunities for training and professional development has the project provided?This project has provided several opportunities for training and professional development, primarily to students at the University of Guam and staff of local and federal government agencies, as well as myself. One undergraduate in the UOG Biology program helped with fieldwork for photographic mark-recapture studies, as part of her directed research project. My graduate student continued her work with tree snails, supported by our new Graduate Assistant Instructor program. These students had an opportunity to learn more about the biology of tree snails, plant identification, field methodology, and limestone forest ecology. These experiences for students are important, as they provided practical training in field research, and exposure to field biology and conservation. Collaborations with various government agencies also provided opportunities for training and personal development. I worked closely with the Department of Defense (DoD) to provide a visual training presentation to locate identify tree snails for contractors. These skills will be important for DoD contractors in identifying endangered tree snails while working in forests on DoD installations. We also further developed the idea of a field guide for native tree snails and identified funding from DoD and USFWS that can be used to layout and publish this document in the future. I obtained funding from USFWS to print a field guide. I also liased with the CNMI's new invertebrate biologist (Broson Curry) and discussed future collaborations and shared data. How have the results been disseminated to communities of interest?One collaborative paper on land snails of a small islet with Dr. Alex M Kerr was published in our the Micronesica journal. This paper reports on land snail fauna there and discusses the possibility of using it as a refuge for partulid tree snails. I also gave presentations on tree snails to federal biologists from DoD, USFWS, and locally DAWR for a separately funded survey methods project. What do you plan to do during the next reporting period to accomplish the goals?I will continue locating and mapping endangered tree snail populations locally and in the CNMI (where possible). We will start measuring physicalenvironmental variables of representative tree snail populations as part of my graduate student's research in the coming months. I will look for a student to do fecal analysis and continue conversations with US zoos with partulid snail rearing programs for future collaborations.

      Impacts
      What was accomplished under these goals? 1) Continue to identify and map populations of partulid snails on Guam, Rota, Saipan, and other accessible Mariana Islands. We found/verified several new populations ofP. radiolataon Guam at locations including coastal Agat and on Naval Base Guam. Tips from collaborators helped us locate populations near Mt. Alifan and Yona.A sixth population of the uncommonS. fragiliswas located in Santa Rita adjacent to a residential area with no sympatricPartula species. We also reported habitat destruction and possible mortality ofP. radiolataat Asan Memorial Park, Tanguisson Beach Park, Tumon, and two areas in the forest near Agana Tennis Courts to USFW and DAWR. 2) Characterize the physical and biological features of habitats where tree snails occur. We acquired hemispherical lenses for canopy measurments as well as several environmental data loggers (air humidity, temperature) and began developing methodology for using and deploying them for a full scale project as part of my MS student's thesis research. I did not carry out work for goals 3 & 4 in this project year.

      Publications

      • Type: Journal Articles Status: Published Year Published: 2019 Citation: Kerr, A.M. & G.C. Fiedler. 2019. Land snails of Alupat Island, a fringing islet of Guam, Mariana Islands, Micronesica 2019-02, 6 pp.