Invasive Plant Species Management at Gwynedd Wildlife Preserve, Ambler, PA
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University of Pennsylvania ScholarlyCommons Master of Environmental Studies Capstone Department of Earth and Environmental Projects Science 2014 Invasive Plant Species Management at Gwynedd Wildlife Preserve, Ambler, PA Nathan Hartshorne University of Pennsylvania Follow this and additional works at: https://repository.upenn.edu/mes_capstones Part of the Environmental Sciences Commons Hartshorne, Nathan, "Invasive Plant Species Management at Gwynedd Wildlife Preserve, Ambler, PA" (2014). Master of Environmental Studies Capstone Projects. 57. https://repository.upenn.edu/mes_capstones/57 This paper is posted at ScholarlyCommons. https://repository.upenn.edu/mes_capstones/57 For more information, please contact [email protected]. Invasive Plant Species Management at Gwynedd Wildlife Preserve, Ambler, PA Disciplines Environmental Sciences | Physical Sciences and Mathematics This presentation is available at ScholarlyCommons: https://repository.upenn.edu/mes_capstones/57 INVASIVE PLANT SPECIES MANAGEMENT AT GWYNEDD WILDLIFE PRESERVE, AMBLER, PA Nathan Hartshorne Spring 2014 Daniel Barringer, Natural Lands Trust Sarah A. Willig, PhD, University of Pennsylvania Hartshorne 2 Hartshorne 3 Acknowledgements: When choosing a project for school, it is important to find a topic that forces you to really learn. If you are already something of an expert, you may create a better work, but you will get less out of it. There is a balance, however, in trying not to choose something too far over your own head. Trial by fire leads to many a burned person. Fortunately, to keep from getting overly scorched, there were several people without whom I never would have managed to complete this project. First and foremost is my academic advisor, Dr. Sarah Willig who met with me at Gwynedd Wildlife Preserve on multiple occasions and on campus at the University of Pennsylvania on several other occasions. She also responded to more emails than I can count, assisting in planning, species identification, and edits. Next is Dan Barringer, without whom the project literally never would have existed. Aside from introducing me to the subject and preserve itself, his expertise was especially helpful when literature tried to take me astray. Janet Novak was also an extremely important resource. There are many plant species to know and she volunteered to assist me in identifying samples that had me stumped. Peers of mine at the University of Pennsylvania include Michael McGraw and Michelle Mancini, neither of whom are experts at invasive species or botany, but took the time to help me survey the preserve. Our knowledge supplemented each other, making for better surveying and learning all around. Even when the combined knowledge was lacking, they kept my spirits high and the internal workhorse working. Hartshorne 4 Hartshorne 5 Table of Contents: I. Introduction to Invasive Species 7 A. Introduction 7 B. Definitions 7 C. History of Non-Native Distribution 8 D. Methods of Non-Native Distribution 9 E. Plant Adaptations 11 1. Non-Native Plant Adaptations 11 2. Native Counter-Adaptations 13 F. Invasive Species’ Impacts 15 1. Ecological 15 2. Economic 16 3. Positive Impacts 18 G. Policy 19 1. International Systems 19 2. United States Government 20 3. Pennyslvania Government 22 4. Examples From Other Countries 23 II. Gwynedd Wildlife Preserve 25 A. Introduction 25 B. Geology and Climate 27 C. Vegetation Communities 27 D. Land-Use History 29 E. Threats 30 III. Methods of Management 33 A. Introduction 33 B. Beginning an Invasive Management Plan 35 C. Enacting Invasive Species Control Methods 36 1. Physical/Mechanical Methods of Control 36 2. Chemical Methods of Control 37 3. Integrated Management 39 4. Biological Methods of Control 40 D. Issues Specific to Southeast Pennsylvania and Gwynedd Wildlife Preserve 42 1. Deer Management 42 2. Invasive Worms 44 3. Emerald Ash Borer 46 4. Beech Bark Disease 46 IV. Controlling Non-Native Plants at Gwynedd 47 A. Priority Ranking of Plants 47 Hartshorne 6 B. Priority Ranking of Habitat 48 C. Other Issues 50 V. Non-Native Plant Species of Gwynedd 55 A. Introduction 55 B. Trees 57 C. Shrubs 85 D. Vines 104 E. Herbs 115 F. Grasses 179 VI. Maps of Non-Native Species at Gwynedd Wildlife Preserve 187 A. Introduction 187 B. Background to Surveying 187 C. Methodologies Used 188 D. Improvements and Further Study 190 E. Trees 192 F. Shrubs 205 G. Vines 214 H. Herbs 218 I. Grasses 234 Appendix A: Tunnel Woods Farm 237 Appendix B: New Plant Species Found in Gwynedd and not Tunnel Woods 240 Appendix C: Fauna 241 Works Cited 246 Hartshorne 7 I. Introduction to Invasive Species Introduction One of the most serious threats to ecosystems worldwide is from the pressure exerted by non- native species entering new habitats that are not part of their native ranges. While the movement of species is a regular occurrence, the unprecedented rate at which humans are introducing organisms to new areas represents a new era. Non-indigenous organisms can alter ecosystem functions and negatively impact native species. Spread by humans in the increasingly connected world, non- indigenous organisms’ global presence does not appear to be declining any time soon. Until relatively recently in human history, distances around the globe were vast, as one could only travel as far as he or she could walk or run. Animals such as horses were domesticated and turned to transportation; ships were built to carry people and goods from place to place. Distances metaphorically shrank as one could get further faster and with more ease. Today people can get from any part of the globe to any other part within hours or days. Experts from a variety of fields have been discussing this dwindling of distances. For a biologist, this is comparable to the creation of a new supercontinent where organisms that had been separated by oceans were now within reach, but rather than a land bridge connecting everything, it is a human bridge of ships and airplanes. Terms such as “New Pangea,” “Anthropocene,” and “Homogocene” have been created to reflect this concept (Crutzen 2002; McKinney 2005). Surprisingly, this is not a strictly modern concept. In the 1800s, terms such as “Anthropozoic,” “Psychozoic,” and “Noosphere” had also been developed to indicate the departure from the Holocene. Of course, the changes in ecosystem dynamics today are likely far bigger than the original authors imagined over a century ago. And with the rapid spread of invasive organisms, some see the future Earth as little more than a “planet of weeds” (Zalasiewicz et al. 2010). Definitions Aside from physiological descriptions of plants and animals, a native habitat is an important descriptor. This tells people where they came from and to which ecosystems they are adapted. Terms such as “indigenous” and “native” reflect where an organism’s native habitat is located. Definitions include “originating naturally in a particular country or region” and “applied to a species that occurs naturally in an area, and therefore one that has not been introduced either accidentally or intentionally” (Schwartz 1997). Therefore, when an organism is moved to a new area, perhaps by natural processes or by another animal such as humans, it becomes “non-indigenous” or “non-native” which are the terms that will be used interchangeably in this paper. Sometimes sources refer to them as “exotic” or “alien” referring to their distant origins. The next important definition is regarding how damaging an organism is to its new environment. When an organism spreads rapidly in a new habitat, altering the ecology, it is termed “invasive.” Only a fraction of non-native organisms act in this manner, and so are not considered invasive (Baskin 2002). Although some native species can be aggressive, in this paper, unless specifically stated otherwise, species labeled invasive are also non-native. Many researchers have created methods to predict which species are invasive or not. None are perfect, though many have high degrees of accuracy. There have been many traits determined to increase a plant’s likelihood of turning invasive. Studies have suggested mean seed mass, minimum juvenile period, growth rates, photosynthetic rates, nitrogen concentration, and specific leaf area are Hartshorne 8 key indicators. Another indicator is if a species has invaded another region of the world (Reuben and Drake 2009). History of Non-Native Distribution There is no one way in which humans have introduced organisms around the world and it is not, in fact, a new development since Western Imperialism. The human transport of non-native species has a rich and ancient history. As agriculture developed around 10,000 years ago, these newly domesticated, or even just semi-domesticated, plants were transported across great distances to be farmed. Today the farming of non-native species alone is worth over 8 billion US dollars (Baskin 2002). But the early introductions of alien species were not limited to just agriculture. About 4,000 years ago, an Egyptian queen sent ships down the coast of Africa to find incense trees for her gardens. Greeks and Romans used ships to sail far in search of fragrances, medicinal plants, and flowers. Even remote islands of Polynesia had fruits and spices brought in from Malaysia centuries ago. As European exploration, and then imperialism, grew, so did the spread of non-native species. In many cases, the explorers saw themselves as helpful, leaving pigs, goats, and even planting crops in places they visited, so the next people to come by would have a food source. By the 1800s, when Darwin made his famous trip in the Beagle, he observed so much damage to the Pampas by European invasives he doubted, “whether any case is on record, of an invasion so grand a scale of one plant over the aborigines” (Baskin 2002). Sometimes it is easy to figure out which species are native and which are non-native. However, historical records are not always clear and such classifications are difficult.