Applied science to inform conservation and restoration of a threatened habitat type; the salt marsh upland ecotone

Transcription

1 Applied science to inform conservation and restoration of a threatened habitat type; the salt marsh upland ecotone By: Cherie Crawford California State University at Monterey Bay May 2012 to February 2013 Advisor: Dr. Kerstin Wasson, Research Coordinator, Elkhorn Slough National Estuarine Research Reserve Submitted: March 15,

2 Table of Contents Acknowledgements 3 Executive Summary 4 Project Objectives 5 Project Approach 6-7 Project Outcomes 8-9 Conclusions 10 Appendices

3 Acknowledgements This project was supported by Agriculture and Food Research Initiative Competitive Grant no from the USDA National Institute of Food and Agriculture. Additionally, I would like to thank Dr. Kerstin Wasson, research coordinator at the Elkhorn Slough National Estuarine Research Reserve for giving me the opportunity participate in this project and Carla Fresquez from UC Santa Cruz for allowing me to assist on her thesis project concerning ecotones. 3

4 Executive Summary This project at the Elkhorn Slough National Estuarine Research Reserve (ESNERR) has many tasks associated with ecotone habitats. The salt marsh upland ecotone is a threatened habitat type throughout the Elkhorn Slough and there are many projects associated with determining the value this habitat has as a transition zone. In the fall, I continued an ecotone wildlife monitoring experiment begun that summer, which includes deploying cameras, sorting through pictures, and drawing conclusions on habitat use based on animals found in the habitat zones. In December, I gave a presentation summarizing our findings of the ecotone wildlife monitoring project to a group of stakeholders at ESNERR. Throughout the duration of my internship, I assisted a Carla Fresquez, a graduate student at UCSC studying the effects of ecotonal plant species in boundaries found above and below the ecotone transition zone. This assistance involved analyzing soil samples, assisting with elevation surveys, solitary data collection, and plant propagation and restoration. I also assisted with an annual long-term monitoring project of ecotone zones as an indicator of climate change. 4

5 Project Objectives The purpose of this project was to use applied science to improve management of the salt marsh-upland ecotone at Pacific coast estuaries, with emphasis on wetlands in the Elkhorn Slough. Ecotones are transition zones between adjacent ecological systems that are sensitive to environmental changes and may serve as indicators of global climate change. The marshupland ecotone is only a few meters wide at Elkhorn Slough and is a highly threatened habitat type important for ecosystem function. This project involved assisting multiple aspects of slough management and had many specific tasks associated with it, outlined below. While I assisted in each of the following tasks, my primary task was to monitor wildlife corridors and conduct field assessments to determine habitat value and level of use (Task A). This task was very field intensive and did not allow for me to assist with restoration experiments (Task B) as much as anticipated. A. Determining wildlife corridor and habitat value of ecotone B. Restoration experiments to enhance ecotone extent C. Investigating factors setting ecotone boundaries D. Correlation of plant community with environmental gradient E. Long-term monitoring of ecotone as an indicator of climate change F. A presentation to stakeholders Following the completion of this project and graduation from California State University at Monterey Bay, I am hoping to use the skills and experience I have gained as an intern at ESNERR in a career with the Natural Resources Conservation Service in natural resource management or with the United States Forest Service. 5

6 Project Approach The methods used for achieve each of the tasks listed above are detailed below. A. Determining wildlife corridor and habitat value of ecotone: From August 2012 to December 2012, I deployed wildlife monitoring cameras at 10 sites on and near Elkhorn Slough two weeks at a time to monitor wildlife use of the ecotone, marsh, and upland zones (Appendix A). The sites were Azevedo, Coyote marsh, Footbridge, Long Valley Dock/Tip, North Marsh, Packard, T Dock, Whistlestop, Willowbend, and Yampah (Appendix B). At each site, I conducted field assessments of plant species, percent cover, litter depth, and canopy height for each zone,, and noted the presence or absence of trails to determine whether any of these factors influenced wildlife use. We hypothesized that the ecotone serves as a wildlife corridor and is more heavily used than the lowland marsh or upland vegetation because of its transition zone characteristics and lower canopy height, leading to higher species richness and abundance. B. Restoration experiments to enhance ecotone extent: The importance of doing the other project did not allow me to participate in this experiment as much as I had anticipated. C. Investigating factors setting ecotone boundaries: I assisted Carla Fresquez from UCSC on her thesis project, conducted at sites near and around Elkhorn Slough. Her project involved transplanting ecotone specialists (Jaumea carnosa, Frankenia salina, and Distichlis spicata) above, at, and below the ecotone transition zone, both with and without the removal of competitors to determine the role of physical and biological factors in setting ecotone boundaries. Some of my duties were collecting soils samples and analyzing them for salinity, ph, moisture content, and organic content, continued removal of competitors in each of the transects, and data collection for each transect. 6

7 D. Correlation of plant community to environmental gradients: I assisted Carla Fresquez with the collection of plant community data across elevational gradients of the marsh-upland ecotone and conducted elevational surveys with RTK GPS and a surveyor's auto-level for the same project. E. Long-term monitoring of the salt marsh-upland ecotone as an indicator of climate change: I assisted ESNERR in an annual long-term monitoring of ecotone dynamics at permanent transects throughout Elkhorn Slough, as part of a ten year monitoring program, to determine whether landward migration of the ecotone is continuing as an apparent response to sea-level rise. Data collection included analyzing plant composition measuring specific species growth. F. Presentation of ecotone wildlife monitoring to stakeholders: Following the conclusion of the ecotone wildlife monitoring for the fall and using data collected during the previous summer, I gave a presentation about ecotone and habitat use by mammals to stakeholders informing them of this project occurring at Elkhorn Slough and potential implications from the results. 7

8 Project Outcomes The following project outcomes are results of my primary task involving ecotone wildlife monitoring. I assessed the following potential correlates to determine if the hypothesis that ecotone serves as a wildlife corridor and is more heavily used than the lowland marsh or upland vegetation is supported: vegetation transects (plant cover, bare ground, litter depth), physical (precipitation, fog, moon), and the season (summer vs. fall). Appendix C is a summary of all the animal species detected across all sites. The ecotone wildlife monitoring for the fall and subsequent analysis of pictures taken at each site and zone lead to the following outcomes, by zone: animals did not show a preference between zones (marsh, ecotone, upland) total number of animal species did not differ across zones deer and coyote, the most abundant species, did not show a preference for a zone, although the highest abundance for both was the ecotone. When comparing season and zones: a higher diversity of species was seen in the fall vs. the spring in all zones significantly more deer were present in the fall across all zones coyote abundance was higher in the fall (though not significantly) more than 50% of the deer sightings in the fall were between sundown and sunrise while less than 50% of sightings in the summer were between sundown and sunrise. When investigating the impact of a trail on animal abundance, there seemed to be no effect of total animal species seen, but there was a higher trend for deer and coyote abundance in the presence of a trail. Neither trend was significant however. 8

9 A cursory analysis of the impact of environmental variables on corridor use revealed: deer foraging was more common in the ecotone than the marsh, but it was not significant total animals species seen was best explained by the combination of more bare ground and less moon deer abundance shows a positive relationship with rain and bare ground. 9

10 Conclusions The following are conclusions from the primary task of the project: there is a high diversity of animal species using the Reserve and other neighboring properties deer was the most common animal seen, followed by coyote more animals were seen in the fall than in the summer (more species and more deer) there was huge variation between sites, with sites on the Reserve peaking in abundance and other sites off the Reserve had little or nothing. We rejected the hypothesis that the ecotone was used more heavily than adjacent habitat types. Other sources of error include inadequate sampling design, and the zones we monitored at each site were too close together (we need a larger spatial scale). However, there was no evidence of a barrier to movement or habitat use and animals were able to move freely between each zone. Future research could include: having a different sampling design (marsh and upland zones further from ecotone), how different sites and properties are used by animals, and the role of topography and barriers influence their use, comparison of habitats further away from the marsh, and achieving a better understanding of wildlife trails, connectivity, and movement. Overall, this internship at ESNERR has given me the experience and skills necessary to further my goal of working with either the National Resources Conservation Service or the United States Forest Service, specifically pursuing habitat and wildlife management and soil conservation. 10

11 Appendix A Coyote marsh on Elkhorn Slough National Estuarine Research Reserve and the three zones where monitoring cameras were deployed. Marsh Ecotone Upland 11

12 Appendix B Fall 2012 wildlife monitoring sites. Sites on Elkhorn Slough National Estuarine Research Reserve included: Coyote marsh, Footbridge, Long Valley Dock/Tip, North Marsh, T Dock, Whistlestop, and Willowbend. 12

13 Appendix C Summary of all animal species seen at various sites, both on and off Elkhorn Slough National Estuarine Research Reserve. 13