Critical Reading

Critical Reading. Student Assignment: Exercise 2 Module M10-GEM-102: Research Proposal Writing University of Twente, MSc GEM Course 2009/2010 Lemenkova Polina July 3, 2010 Abstract Exercise 2: Critical Reading, based on the publication: Cayuela L., Benayas J.M.R., Echeverria C. 2006. Clearance and fragmentation of tropical montane forests in the Highlands of Chiapas, Mexico (1975-2000). Forest Ecology and Management 226, 208-218. 1 Critical Reading: Comprehension 1.1 Why was this research done? The motivation for this research is estimation the deforestation rate during the 25-year period, and detection of changes in the spatial configuration in the forests of the Mexican ecosystems for environmental management purposes. Overusing of the natural resources has lead to the drastically destroying of the forests. The authors used remote sensing techniques for monitoring the deforestation. The paper focuses on “real-world” question, as the main research of interest is Mexican unique mountainous forests (Central Highlands of Chiapas). As a result of research, the loss of forests area was detected, proved by exact calculations (about 50%). The research is done using supervised classification method and Dempster-Shafer algorithm. The authors did very careful analysis of the loss of forests which is very difficult to estimate in this region, because there are some transit types of vegetation. 1.2 What does this paper claim to do about the problem? In other words, what is new? This paper claims to propose improved methodology in the estimating of the deforestation in the Mexico area, and assessment of changes in the spatial configuration of forests. The core question of this article is estimating the deforestation rate, loss of forest and changes in forest patterns in Mexico, using classification methods of Idrisi. As a result of a scrupulous analysis, the deforestation rate was estimated for environmental monitoring of the Mexican Highlands. The authors propose new approach in analysis methods: estimation of confusion matrix, correction of land cover using Idrisi, which allows better estimation of the land cover classes by using lines of evidence derived from multi-spectral data and expert knowledge. Thus, the existing supervised classification methodologies are improved with application to the case study. Therefore, the paper proposes a better answer to the current problem of deforestation in Mexican Highlands. 1 Lemenkova Polina: Student Assignment ’Critical Reading’. Exercise 2 for the Module M10-GEM-102: Research Proposal Writing. University of Twente, July 3, 2010 1.3 What methods do the authors use to address the problem? The methodology of the paper is based on using the algorithm of supervised classification using Dempster–Shafer procedure from the Idrisi software. The technical tool of the research is applications of the remote sensing technical methods (Idrisi 32) and spatial analysis using Landsat satellite imagery from 1975 (MSS), 1990 (TM) and 2000 (ETM+). The initial resolution of 79 meters was resampled to 30 m to achieve the quantitative compatibility of the images. The images were improved by geometric, topographic and atmospheric correction. The vegetation gradient was estimated in the process of experimental generalisation. The land classes were defined by estimating the probabilities of each pixel belonging to the land classes in years 1975, 1990 and 2000. To assess quality of the research, the accuracy of the images was assessed in confusion matrices. The result of the ETM+ land cover map was proved by comparing with 303 independent real ground control points selected in the field. The analysis of the classification land cover map was technically based on the ArcView (Spatial Analyst module). The estimation of the deforestation rates and increasing of non-forest areas (60.3%) was made using compoundinterest-rate formula. It is also estimated that the most vulnerable forest type is montane cloud forest are mostly suffering (decreased from 19.7% of the study area in 1975 to 2.5% in 2000). Annual deforestation rate was about 2.7% year for the entire study period. Patterns of forest fragmentation were calculated using landscape indices. 1.4 What is the result of applying these methods? The results of this study are estimation of the deforestation rate, forest patterns changes (structure, composition and degradation) and analysis of the reasons for the deforestation (both natural and anthropogenic). Annual estimated deforestation rate during the past 25 years in the Mexican tropical forests in a Highlands of Chiapas is 2.7 +- 0.3% year for the entire study period. Forest loss was lesser in the first 15 years, at a deforestation rate of 1.3 +- 0.5% year, and then increased to 4.8 +- 0.7% year in the 1990–2000 years. Besides the rates of deforestation, land cover patterns were classified: about 50% of the native forest existing in 1975 was deforested by 2000. Total area of forests decreased from 216,363 ha (61.7% of the study area) in 1975 to 109,087 ha (32.0%) in 2000, an increase of total area of non-forest areas (60.3%). 1.5 Are there any case studies? If so, what is the relation of the case study to the preceding theoretical development? This paper is a case study of estimation of deforestation rate and fragmentation of tropical mountainous forests in Mexico during 25 year period from 1975. The research area is forests covering mountainous region of Mexico, Highlands of Chiapas, with heights from 600 to 2900, extending over 3500 km2, with limestone carboniferous underlying geology and mixed soils. The relation of this case study to the preceding theory consists in the application of the remote sensing techniques (based on Idrisi software) to the deforestation rate estimation and land cover monitoring (e.g. using technique of correct identification of pixels belonging to each land class, interpretation of the vegetation types and estimation the loss of forests).Thus, this research is a good case study of deforestation, due to the anthropogenic overuse: it is estimated that half of the total forest areas has been destroyed during the 25 years. 1.6 What makes the claims scientific (based on facts and logic), as opposed to being mere opinions? The results are based on the exact estimation of the deforestation rate and supported by the accuracy assessment. The estimation is done using algorithms of land cover classification and Page 2 Lemenkova Polina: Student Assignment ’Critical Reading’. Exercise 2 for the Module M10-GEM-102: Research Proposal Writing. University of Twente, July 3, 2010 detecting the area classes. During the estimation of areas belonging to one or another land cover class the authors used scientific methods with five lines of evidences: covariance matrix of multispectral data, elevation data, slope angles, distance to human settlements and main vegetation types in the landscape perception. The research has been done using expert knowledge, i.e., combination of theoretical understanding of the processes and experimental classification. Therefore, based on correctly used facts and methodology, claims are scientific. 1.7 How do the authors substantiate (back up) their claims? The research claims are substantiated by scientific methods and data used in the research, final results received and accuracy assessed. The Landsat satellite images were used for estimation of deforestation rate and spatial pattern changes. The calculation of deforestation rate is based on land classifications using Dempster-Shafer’s algorithm in Idrisi. For improvement of quality of images pre-processing methods were used. The classification accuracy assessment were 89.8% for the 1975 MSS image, 90.7% for the 1990 TM image and 94.1% for the 2000 ETM+ image. For evaluation of the results, field measurements were done, and the error matrices were calculated. Besides the deforestation, the authors evaluated and assessed consequences of the deforestation in different aspects of biodiversity: structure and composition of forests, cover states of different vegetation types, decrease of changes in some species. All research was carried out using ArcView and Idrisi software and based on existing methods and algorithms. 1.8 What conclusions do the authors draw from their results? The results received by the authors in this article can be applied to mountain forests monitoring in highland regions, and research of vegetation pattern changes. The principles of the spatial analysis using classification algorithms techniques, used in this research, are suitable for monitoring the environmental changes. Therefore, this article is of general interest for environmental studies. Going beyond the technical question of monitoring the deforestation rates, authors appeal to general ideas suggesting the intensifying of political and conservation actions to prevent the disappearing of the forests ecosystems and further deforestation caused by overexploitation. The results of the research can be used in natural resources management. 1.9 What could we get out of the paper for our own work? Estimation of changes in the ecosystems based on supervised classification method which requires accuracy assessment. According to the authors, classification process can bring some problems while assessing land cover classes and the pixels belonging change detection methods, and difficulties may also arise at the generalization process. Therefore, the land cover area classification should be corrected by using error matrix. 2 Evaluation 2.1 How significant is the research problem? The problem the article is dealing with is a real problem of deforestation and loss of biodiversity in Mexican tropical mountainous forests. The problem of biodiversity loss and deforestation of tropical forests in the world is well-known nowadays. However, the Mexican region of Central Highlands of Chiapas is not so well-discussed in the scientific circles, because of its specific location and difficulties of loss rate estimation. Yet the authors give citations to other scientific publications focusing on the problem of Mexican forests degradation. Authors report that forest Page 3 Lemenkova Polina: Student Assignment ’Critical Reading’. Exercise 2 for the Module M10-GEM-102: Research Proposal Writing. University of Twente, July 3, 2010 loss has been a continuous, severe and yet not solved problem during the last decades. The article highlights a part of the problem of the Mexican forests degradation, but it contributes considerably towards solving of the problem, because, the study area covers a region of about 300 km2 , and the Highlands of Chiapas: about 50 km2 . Therefore, the region of interest covers significant area of the total Mexican forests. The conservation of the rainforests in Mexico is important not only for the local communities and Mexican government, but for the survival of the whole humanity, because rainforests are lungs of the Earth. Thus, this research is an actual and challenging one. 2.2 How significant is the contribution to solving the problem? The authors are aware of the relation of their work to existing literature, support their work by extensively using ideas and concepts of other authors with accurate citations and references. The results are surprising for the reader who does not previously had any idea about the real actual situation of deforestation in the Mexican highlands. The result of the work showing that about 50% of the forests are disappeared impresses even the non- environmentalist. However, from the methodological and technical points of view, the results are the consequences of the research, because they accurately done and logically described. The work gives us the new acknowledgement of the efficiency of using remote sensing techniques in the problem of environmental monitoring. As the authors declare, their work is one ’further evidence of the usefulness of remote sensing approaches to monitor deforestation rates’ (Cayuela et al, 2006). It develops further application of the Idrisi software towards the solving of ecological problems. The work has a good practical application for the environmental policies of the Mexican government or for any conservational research group specializing on the monitoring the South American nature. 2.3 Are the claims valid? The scientific work in the article has been carefully done with proper level of details using remote sensing techniques and proper methodology. Using remote sensing techniques for images processing is methodologically correct for purposes of land cover classification and environmental changes monitoring. Among the important results of this research the following were received: land cover classification, deforestation rates, estimation of the pattern changes in the land cover and final maps illustrating the deforestation and spatial variations of forests and coffee plantations areas. The atmospheric and geometric correction of the images was done before the classification process. The accuracy of the research was measured using error matrices made from ground control points. The methods and algorithms used in this work were used correctly and with detailed description and explanations: supervised classification with six defined classes and Dempster–Shafer’s classification algorithm implemented in Idrisi, compound-interest-rate formula of ArcView. During the research all the important factors are considered, and the final results completely support the author’s conclusions: deforestation rate, loss of forests areas during the last 25 years and changes in the spatial land cover pattern. The authors refer to publications of other scientists focusing on deforestation problem and changes in land cover patterns, and give comparison of their own results with the ideas reported by other authors in other study areas (Chile). The authors conclude that changes in the Highlands of Chiapas may result in serious consequences for the biodiversity structure. In suggestions they propose change of the conservation strategy in the Mexican forests environment from traditional reserve to the integrated landscape management. Therefore, authors’ claims are valid, because the consequences of deforestation in Mexican highlands can lead to environmental collapse. Page 4 Lemenkova Polina: Student Assignment ’Critical Reading’. Exercise 2 for the Module M10-GEM-102: Research Proposal Writing. University of Twente, July 3, 2010 3 Abstract Tropical forests are of great importance for the world environment, yet they are in danger of deforestation due to the overusing and agricultural activities. Very important problems nowadays are deforestation and land patterns fragmentation, leading to negative consequences on global environment and biodiversity. Increase of population and overusing of land for agriculture led to forest degradation over 25 years. Estimation of deforestation rates and changes in land cover patterns are necessary for forests conservation and monitoring. The main objective of this research is estimation of deforestation rates and forest degradation in the Highlands of Chiapas, Mexico during the period of 1975-2000. The research was technically based on Arc View and Idrisi. Landsat images were used to analyse loss of forests over 25 years (50% of total area). Objective of this research is detection of changes from 1975 until 2000. The analysis of the deforestation rate was done using corrected satellite images of Landsat MSS, TM and ETM+. The core method is supervised classification with six defined classes using Dempster–Shafer procedure. Estimation of annual deforestation rates was done using compound-interest-rate formula. Specific landscape indices were used for calculation of forest fragmentations. The accuracy estimation was measured using confusion matrices, made by comparing of GCPs to final classified map. Almost 50% of the forests were lost by 2000: the estimated area of native forests decreased from 61.7% of the area in 1975 to 32.0% in 2000. Montane cloud forests are most vulnerable towards degradation with decrease from 19.7% to 2.5%. Total annual deforestation rate increased from 1.3% in period of 1975-1990 to 4.8% in 1990-2000 with the mean size of forest patches decreased at the same time. Forests monitoring and risk assessment must be developed by conservation policy services for the conservation of this unique region from complete degradation. 4 Bibliography Author’s publications on Geography, Remote Sensing and GIS: 1 S. Gauger, G. Kuhn, K. Gohl, T. Feigl, P. Lemenkova, and C. Hillenbrand, “Swath-bathymetric mapping”, ANT-XXIII/4 R/V ’Polarstern’ 557, 38–45 (2007). 2 K. Gohl et al., Crustal and Sedimentary Structures and Geodynamic Evolution of the West Antarctic Continental Margin and Pine Island Bay (Bremerhaven, Germany, 2006). 3 P. Lemenkova, “Using ArcGIS in Teaching Geosciences”, Russian, B.Sc. Thesis (Lomonosov Moscow State University, Faculty of Educational Studies, Moscow, June 5, 2007), 58 pp. 4 P. Lemenkova, “Geoecological Mapping of the Barents and Pechora Seas”, Russian, B.Sc. Thesis (Lomonosov Moscow State University, Faculty of Geography, Department of Cartography and Geoinformatics, Moscow, Russia, May 18, 2004), 78 pp. 5 P. Lemenkova, Ecological and Geographical Mapping of the Baltic Sea Region in the Gulf of Finland, Russian, Moscow: Lomonosov Moscow State University, Mar. 30, 2002, Term Paper. 6 H. W. Schenke and P. Lemenkova, “Zur Frage der Meeresboden-Kartographie: Die Nutzung von AutoTrace Digitizer für die Vektorisierung der Bathymetrischen Daten in der Petschora-See”, German, Hydrographische Nachrichten 25, 16–21 (2008). 7 I. Suetova, L. Ushakova, and P. Lemenkova, “Geoinformation mapping of the Barents and Pechora Seas”, Geography and Natural Resources 4, 138–142 (2005). Page 5