GIS and Remote Sensing Applications in Invasive Plant Monitoring

Matt Wallace NRS 509 Written Overview & Annotated Bibliography 12/17/2013 GIS and Remote Sensing Applications in Invasive Plant Monitoring Exotic invasive plants can cause severe ecological damage to native landscapes once established. Such species can spread rapidly across large areas and often times travel undetected until significant infestation has occurred. Therefore, georeferenced data regarding the distribution of invasive plants can be extremely beneficial in controlling their continued spread. GIS and remote sensing technologies have contributed to the monitoring, prevention and mapping of invasive plants in order to help control past and future outbreaks in many different ways. These technologies are continuing to play a major role in helping to contain already established exotic plant populations, as well as identifying other vulnerable habitats. Here, I will discuss ways in which GIS and remote sensing has furthered our understanding about invasive plant movement. There are many different applications of these technologies in this field; the following is an overview of a few of the most popular and interesting ways GIS and remote sensing are being used. GIS and remote sensing technologies are ideal for analyzing the spatial distribution of a certain feature throughout a large landscape. Thus, both can be excellent tools in improving our understanding of invasive plant movement. Gathering field data on invasive plants can be a long, tedious and often times an impractical procedure. Mapping invasives has become much more accurate through the use of georeferenced data, shown through GIS and remote sensing. In order to understand what areas might be affected by an invasive plant infestation, it must first be understood where it has already established. Many of the studies I reviewed started with first mapping already existing location of an invasive plant. After this is completed, this information can be used to estimate the percent growth of a species, how fast it has spread, and where it may likely go next. GIS databases can be constructed to act like an inventory of invasive plant characteristics. This can give land managers opportunities to set up early detection procedures in order to prevent an invasive from establishing elsewhere. Similarly, models can recognize existing conditions ideal for a particular plants growth and use this information to predict its range based on climate change and habitat alteration. One interesting application I read about was using GIS to run a cost benefit analysis to determine what areas should have highest priority in being treated for a specific invasive plant. The reality with many invasive plants is that there are so many outbreaks and so little time and money to control all of them. Land managers need to prioritize the most cost effective way to treat the most negatively impacted areas first. GIS can take various ecological and economical factors into consideration when mapping areas to treat, identifying areas of highest value. One particular study examined factors such as travel times to the infested areas, difficulty getting there, and impacts the invasive may have on human usage within the area (fishing, military training, farming, etc.) in order to prioritize for treatment. Remote sensing is perhaps equally as effective in controlling the spread of invasive plants. This technology is designed to recognize the spectral signature of surfaces on land, identifying objects found within an image that the human eye couldn t. Many studies use remote sensing as a way to identify and, when necessary, predict areas where an invasive may 1

be located. However, a somewhat common problem that seemed to arise is the ability to accurately identify plants located on the forest floor and beneath tree canopies. This is a challenge because the spectral signature of the plant is blocked or severely diminished and thus we cannot be absolutely certain if the plant is established in that particular area. Nonetheless, users of the imagery can train the system to identify the spectral signature of a specific plant in order to make an interpretation of where it may be located. The accuracy of identifying plants using satellite imagery is somewhat dependent on the resolution. Commonly, studies indicate the need for very specific resolutions depending on the area they are assessing. High resolution imagery can be very accurate in identifying plants located within a very heterogeneous environment, however this imagery is often very expensive and thus may not be practical for large scale applications. Many studies I examined stated the need to balance the use of expensive, high resolution imagery with medium resolution imagery that is free from providers such as the Landsat system when identifying invasives. The possibilities for GIS and remote sensing applications within this field seem to be endless. Although similar in principal, many of the studies used these technologies in slightly different ways demonstrating their versatility. The literature on this topic is very extensive, suggesting that these tools are very effective in monitoring, mapping, and predicting invasive plant movement in a variety of different settings. This overview barely scratched the surface of how these tools can be used in the field of invasive plant science, however the basic and most common ways in which they are used are outlined above. I firmly believe that both GIS and remote sensing will continue to be strongly used within this field, especially as technology advances making them even more efficient. A breakthrough such as the availability to free Landsat data is a perfect example of how the evolution in this technology has made it more practical to use. The future looks bright for GIS and remote sensing for applications in invasive plant monitoring, the technology has surely made an impact on our ability to identify and prevent continued spread of invasive plants. 2

ANNOTATED BIBLIOGRAPHY Dark, S. J. 2004. The biogeography of invasive alien plants in California: an application of GIS and spatial regression analysis. Diversity and Distributions, 10:1 9. This paper sought to find reasons for the spatial distributions of invasive plants throughout California. The author constructed a GIS application that categorized the distribution of invasive plants according to variations in bioregions found in California, something that had yet to be accomplished. This paper expressed the importance of tracking invasives through the scale of bioregions to better understand why different exotic species appear where they do. It was interesting to read about how important scale is when defining your goals within GIS application. As we discussed in class, this study clearly underlines how things are perceived depending on scale and why it might be beneficial to use one scale vs. another. Jarnevich, C.S., T.R. Holcombe, D.T. Barnett, T.J. Stohlgren, & J.T. Kartesz. 2010. Forecasting weed distributions using climate data: A GIS early warning tool. Invasive Plant Science and Management, 3(4):365 375. This study explained ways in which we can use GIS to estimate the probability any particular invasive plant has to spreading into new locations. The authors construct bioclimatic envelopes which incorporate a number of particular climatic parameters in order to categorize an invasive plants preferred habitat based on current areas of establishment. These envelopes hold information about desired habitat suitability according to a where a species already exists and matches its information to similar areas around the U.S. The idea is that land managers can recognize which invasive plants could potentially invade their location based on habitat suitability. This seems like a very practical and proactive way to not only map the distributions of invasive plants, but to recognize the potential for future invasions. This knowledge can help decrease the rate of spread among invasive plants by creating an early detection system for faster treatment. Lu, J., & Y. Jhang. 2013. Spatial distribution of an invasive plant Spartina alterniflora and its potential as biofuels in China. Ecological Engineering. 52:175 181. A majority of the articles I have read regarding GIS and remote sensing applications in invasive species science has focused on mapping invasives in order to establish ways to prevent the plant from spreading into new areas. Often times these technologies are using to determine where exactly these plants are located and the likelihood of them spreading into new locations so managers can enact early detection procedures. I found this article to be very interesting because remote sensing is used to measure the amount of a certain invasive plant across China, valued because of its potential in the use of biofuels. The study isn t focused so much on the early detection and prevention of an invasive plant across a landscape, rather to use remote sensing to estimate the potential energy that could be derived from this invasive plant. It is a very unique way to deal with the problems this plant has caused ecologically, and it could identify a cleaner source of energy in China. The study used remote sensing technologies to map the plant across China, and then used its distribution to estimate the amount of energy that could be harvested from turning this plant into biofuels. This is yet another clever and ecologically beneficial way to use this technology. 3

Masocha, M., A.K. Skidmore. 2011. Integrating conventional classifiers with a GIS expert system to increase the accuracy of invasive species mapping. International Journal of Applied Earth Observation and Geoinformation 13(3):487 494. Masocha and Skidmore examine new possibilities in which to use GIS and remote sensing technologies to map invasive plants. Specifically, they discuss the benefits of using traditional remote sensing imagery coupled with more advanced Expert Systems that can take some of the guess work out of locating unknown areas of possible invasive plant infestations. These Expert Systems are statistically advanced interpolators that can make estimations of areas thought to be suitable for invasive plants in a particular area. I found this very interesting because I never thought of the fact that traditional remote sensing technologies (at least that I am aware of) may have difficulties accurately reading the spectral signature of a plant if it is below a tree canopy or located close to the forest floor. Not only can Expert Systems make accurate assessments of areas where this may occur, but they also reduce the need for manual field observations in places where that might be difficult. Shouse, M., L. Liang, & S. Fei. 2013. Identification of understory invasive exotic plants with remote sensing in urban forests. International Journal of Applied Earth Observation and Geoinformation. 21:525 534. This study examines a common obstacle often confronting remote sensing in an urban environment. The authors explore ways in which to accurately locate the presence of an invasive plant situated within an urban forest. The problem with correctly identifying any invasive in a very heterogeneous environment such as an urban forest is that very high spatial resolution is often needed in order to differentiate low lying understory plants from overhead tree canopies and sharp changes in landscape ground features. This study underlines the importance spatial resolution plays depending on the goals and setting of the experiment. Here, medium spatial resolution imagery is coupled with high spatial resolution information in order to detect the invasive plant in this environment. There are clear advantages associated with using high spatial resolution imagery, however the biggest disadvantage is the high cost associated in using such platforms. Somodi, I., C. Andraz, D. Ribeiro, & T. Podobnikar. 2012. Recognition of the invasive species Robinia pseudacacia from combined remote sensing and GIS sources. Biological Conservation. 150(1):59 67. This paper examined the accuracy and efficiency low cost aerial and satellite imagery has on mapping and assessing a particular invasive plant. Here, the authors wanted to test the usefulness of basic and affordable Landsat satellite imagery and easily obtainable orthophotos in tracking the spread of an invasive plant. They conclude that this imagery, which is free and easily obtainable, can be extremely effective in monitoring invasive species. This study brings up the importance access to data has on using remote sensing technologies to address environmental issues. Now that Landsat imagery is free and easily downloadable, more people can explore the technology and make accurate and meaningful environmental assessments. This type of data sharing can be a strong tool to combat the challenges associated with tracking invasive plants. 4

Yager, L.Y., & M. Smith. 2009. Use of GIS to Prioritize Cogongrass (Imperata cylindrical) Control on Camp Shelby Joint Forces Training Center, Mississippi. Invasive Plant and Science Management. 2(1):74 82. The goal of this paper was to explain how GIS can be used to calculate the most cost effective way to treat an invasive plant within a particular area. The paper explains the importance of recognizing factors that may increase the time and cost necessary to treat an area populated by an invasive plant. They address factors such as distance to infested areas, difficulty getting there, time it takes to get there and importance of treating the area based on other ecological and economic factors. I think it is very important to realize that cost benefit analysis is a must when planning to treat an area for invasives. The reality is that there are so many invasives and so little money; you need to put your resources into treating areas that make the most sense financially and ecologically. GIS is shown here to be a powerful tool in efficiently planning how you might treat an area for invasive plants. 5