Abstract:
The main goal of this study is to examine the habitat loss experienced by the Sumatran Rhinoceros and Pygmy Hippopotamus, within and around the Way Kambas and Sapo National Park. Currently, both of these animals occur in more than one location, but they are extremely small in population size. There are an estimated 300 Sumatran Rhinoceros in the world and about 40 of them currently live in Indonesia's Way Kambas National Park. The national park was established during the 1970's in order conserve biodiversity before it was lost to deforestation. Despite the establishment of a national park, logging and poaching still occur within the park's boundaries. Much like the Sumatran Rhino, the Pygmy Hippopotamus is found throughout several locations and has low population numbers. This animal is endemic to four countries in West Africa, but has recently become regionally extinct in Nigeria. The methods used to illustrate habitat loss in this study are the landsat time series and density slice analysis techniques. Each technique will reconstruct what past habitat ranges once looked like. Much like the results, the major findings for each site also varied. The Sapo study site showed little to none habitat loss or change, but the Way Kambas study site depicted an explosion of land development over a 13 year period.
Intro:
The Sumatran Rhinoceros and the Pygmy Hippopotamus are just two of many animal species that are in dire need of strong conservation efforts. The Sumatran Rhinoceros once had an historic distribution that ranged from Northeast India, throughout Myanmar (Burma), Thailand, Malaysia and the Indonesian islands of Sumatra and Borneo. The range of this animal has been sharply reduced to several scattered National Parks in Indonesia, Malaysia, Sumatra and Borneo, including Way Kambas, Bukit Barisan Selatan, Gunung Leuser, Taman Negara & Tabin Wildlife reserve during the 20th century [2]. Even though the animal has national parks to call home, the Sumatran Rhinoceros is still considered a critically endangered species by the IUCN. The major threats that this animal encounters are habitat loss and poaching. Unlike the pygmy hippopotamus, this animal does not breed well in captivity
There are three subspecies recognized by the IUCN and all of them suffer from the same species threats. Of the three subspecies, only one of them has gone extinct, but the other subspecies are soon to fallow. Currently there are an estimated 300 Sumatran Rhinoceroses living in the wild. There are an estimated 230 of the Western Sumatran Rhinoceros (Dicerorhinus Sumatrensis Sumatrensis). The Eastern Sumatran Rhinoceros (Dicerorhinus Sumatrensis Harrissoni) has an estimated population of about 50 individuals, and the Northern Sumatran Rhinoceros (Dicerorhinus Sumatrensis lasiotis) is now regionally extinct in India and Bangladesh.
The Pygmy Hippopotamus has been listed as endangered by the IUCN during the year 1996. Until that point in time, this animal was only categorized as vulnerable. There are two speculated subspecies of Pygmy Hippopotamus, but the IUCN only recognizes one known species of Pygmy Hippopotamus. The scientific names for both subspecies are Choeropsis Liberiensis Liberiensis and Choeropsis Liberiensis Helopsi. Both species are endemic to the forested areas of Western Africa. The Liberiensis species is a confirmed pygmy hippopotamus species, while the Nigerian subspecies has been seen but never physical examined to determine a subspecies status. Since the Liberiensis subspecies is now listed as regionally extinct in Nigeria by the IUCN, determining the subspecies may be difficult.
The past distribution and historical range of this animal has been poorly documented, however, it is speculated that past distributions and ranges do not differ much from today. Since the animal has been poorly studied, all that we know about this species comes from captive zoo specimens. The total number of pygmy hippopotamuses living in the wild is unknown, but is currently estimated to be around 3,000 individuals [3]. Each subspecies of pygmy hippopotamus can be found in different regions of Western Africa. The Liberiensis subspecies is found in Liberia, while the Choeropsis subspecies is found in Nigeria. The main threats to this animal are habitat loss and poaching.
Given the aforementioned background information on both species of study, it is evident that pressuring human factors are a direct threat to the vitality of these animals. In response to these threats, national parks were established to help preserve the future of each species. The establishment of national parks has proven useful in sustaining viable populations of both animals. However, poaching and habitat loss still threatened the existence of the Sumatran Rhinoceros and Pygmy hippopotamus within their respective parks. This study will use remote sensing to examine the change of environment in and around the Way Kambas and Sapo National Parks.
Method:
The study areas for this project are the Way Kambas National Park in Sumatra Indonesia, and the Sapo National Park in Liberia. The sole determinant of these sites was the presence of an endangered or critically endangered species. The satellite imagery data was obtained from the Glovis web server. Park boundary lines that were later used for digitization were also taken from the Glovis website. The data obtained from the Glovis website helped to conduct a Landsat time series analysis, which resulted in the illustration of physical environmental change over time.
For the Way Kambas Study site, satellite images from the year 1989 and 2002, were digitized in order to show population expansion and park boundary violations. The images were downloaded in gray scale, then the areas of focus were digitized in order to convey a more thematically focused image. This allowed for a better labeling of where the national park is located, where its boundaries have been violated, and where human expansions have occurred. The image was first imported into ENVI in order to subset the image. Next, the gray image was then imported to the ArcGIS program, where the digitizing occurred.
A density slice analysis was conducted for the Sapo study site in order to illustrate changes in vegetation. The density slice analysis was conducted for the years 1988 and 2003. The first step used to conduct a vegetation analysis was acquiring the desired satellite imagery. The next part of the process was to use the ENVI program and create an NDVI of the desired images. After this was done, the image was changed by replacing the green band with the newly created NDVI image. This allows for a better distinction between forested areas and non-forested areas. Next the density slice analysis is conducted and an analysis on the change of vegetation can be made.
Results:
The results for both studies yielded varying degrees of environmental change within and around each national park. The Way Kambas National Park in Sumatra, showed the most change in the study area. When comparing the 1989 satellite image to the 2002 image, it is evident that there was massive human land development that occurred during that thirteen year time period. Upon examining the image, there is evidence of illegal land development occurring within the park. This violation of park boundaries occurred prior to the year 1989, and cannot be seen in the satellite images from different years. Unlike the Way Kambas National Park analysis, major changes in the environment cannot be seen in or around the Sapo National Park of Liberia. With this study site, the changes that occurred were questionable due to the bad satellite imagery obtained for the 1988. Despite the condition of the image, it was the only decent satellite image available for that year. Little change was found when comparing the density slice analysis of two separate years to one another. A positive observation to be made is that the Sapo National Park seems to have recovered from vegetation loss from 1988 to 2003.
Discussion:
Overall, I feel that my study on the Sapo National Park was limited by the lack of clear landsat images. Out of all the images available on the Glovis website, only two photos were able to be used for my study. Most of the photos had contained intense cloud clover or were marred by horizontal lines that ran across the entire satellite image. Also, the lack of high resolution further limited the study in both national parks. During my literature research on both parks, illegal logging was said to be occurring in the parks and this was having a negative effect on the animals living within the park. In my study, I had wanted to find areas of illegal logging, but the satellite images were not of high enough resolution to make this possible.
Two other studies based on deforestation trends also utilized remote sensing techniques to determine to what extant deforestation has occurred. One such study titled, “Deforestation Trends in a Tropical Landscape and Implications for Endangered Large Mammals” conducted by Margaret Kinnaird and a group of researchers, utilized the landsat time series method to reconstruct forest loss over the years [4]. Another technique the research group used was the digitizing method. They were able to use this method due to the clarity of their satellite image. They manually digitized and classified forested areas, farmland, ets,. From the information they gained from the newly digitized forest areas for each of study, the research group was able create an equation that would tell them what forest cover in their study area would be like in the future if current trends were held constant.
One other study on deforestation conducted by Glen Green and Robert Sussman also examined deforestation [1]. Much like the aforementioned study, Green and Sussman wanted to extrapolate what forest cover would look like in the future, except their study site was Madagascar. They used satellite imagery and conducted a time series analysis. However, they took into account elevation data. They were interested in determining the future of forested hillsides and forested flat lands. The hypothesized that forested hill sides would outlast forested flat lands. This duo utilized classification and digitization methods in order to conduct their study.
An interesting study conducted by Ricketts and his research team was determining current locations of imminent extinctions. This was an interesting study aimed at assessing which species is in the most need of immediate conservation efforts. In order to make a correct and accurate assessment of this, a designated species must fit a list of criteria. A species would be taken from consideration if it did not fit one criterion on the list. The results of this study are best stated by the research paper, “Our criteria yield 794 trigger species, distributed among 595 sites, that are likely to become extinct unless immediate and direct action is taken” [5]. Information on the decided trigger species could be potentially useful in saving a species only found in one location in the world from disappearing forever.
In terms of future research, I feel that my study would be more affective in aiding wildlife conservation against the threat of deforestation if the satellite imagery was of higher resolution. It is easy to see change in an environment on a large scale that includes the entire park and surrounding human civilization. However, smaller less obvious changes can be better detected by a higher resolution image focused on a smaller area. With low image resolution, small and subtle environmental changes cannot be detected when studying a large area. In the case of my study, higher resolution satellite imagery for my study sites was unattainable.
Reference:
1. Green, G. M., Sussman. R. W., (1990) Deforestation History of Eastern Rain
Forest of Madagascar from Satellite Images. Science, New series 248, 212-215.
2. IUCN Red List. November 27, 2010. http://www.iucnredlist.org/apps/redlist
/details/6553/0.
3. IUCN Red List. November 27, 2010.http://www.iucnredlist.org/apps/redlist
/details/10032/0
4. Kinnaird, F. M., Sanderson, E. W., O’Brien, T. G., Wibisino, H. T., Woolmer,
Gillian.(2002) Deforestation Trends in a Tropical Landscape and Implications for Endangered Large Mammals. Conservation Biology 17, 245–257.
5) Ricketss, T. H., Dinerstein, E., Boucher, Tim., Wikramanayake, Eric., (2005)
Pinpointing and preventing imminent exinctions. PNAS 102, 18497-18501.
6) USGS Global Visualization Viewer. US Department of the Interior. November 26,
2010. http://glovis.usgs.gov/.
Imagery:
