شاخص‌هاي گسست منظر زمينه تجميع سنجه‌هاي بوم‌شناسي و رويكرد ادراكي

Indicators of landscape fragmentation The case for Combining ecological indices and the perceptive approach

منظر پديده‌اي پوياست و موجوديت چندلايه آن باتمام مقياس‌ها در گذاري هميشگي قرار دارد. از مصاديق گذار و تغيير در منظر، پديده گسست است كه بر تمام لايه‌هاي اكولوژيكي و ادراكي آن در مقياس‌هاي مختلف تاثير مي‌گذارد. گسست در منظر كه تحت تاثير مداخلات انساني روي مي‌دهد پيامدهاي گوناگوني دارد كه از عوامل مختلفي همچون توسعه سكونت‌گاه‌هاي شهري، ايجاد زيرساخت‌هاي حمل‌و‌نقل زميني و ريلي، تسطيح و تصرف اراضي طبيعي براي مصارف كشاورزي و فعاليت‌هاي معدن‌كاوي و عوامل بسيار ديگر ناشي مي‌‌شود. اين نوشتار در پي آن است تا با رويكردي جامع و كل‌نگر به ماهيت منظر، نظريات موجود در خصوص پديده گسست و روش‌شناسي حوزه‌هاي مختلف مرتبط با اين پديده را تحليل كند، به امكان‌سنجي شاخص‌هاي در ارزيابي پيامدهاي گسست در منظر بپردازد و همزمان به جنبه‌هاي اكولوژيك و ادراكي آن توجه كند؛ شاخص‌هايي كه قابليت انطباق بر ويژگي‌هاي خاص هر بستر منظرين را به طور جداگانه دارا باشند و تغييرات ناشي از گسست را در الگوهاي موجود منظر و محيط پيش‌بيني كند. با چنين هدفي شاخص‌هاي ارزيابي پديده گسست به دو گروه كمّي و كيفي تفكيك شده است به شاخص‌هاي كمّي به ويژگي‌هاي اكولوژيك و زيست‌محيطي منظر و شاخص‌هاي كيفي به خصوصيات ادراكي و هويتي آن مي‌پردازد. اين نوشتار در پايان به اين نتيجه خواهد رسيد كه تركيب تمام شاخص‌هاي كمّي و كيفي در تحليل يك بستر منظرين و تبديل آنها به يك كليت واحد به واسطه تفاوت ماهوي اين شاخص‌ها و زمينه‌هاي مختلف دلالت آنها امكان‌پذير نخواهد بود، لكن با تعريف اولويت‌هاي ساختاري هر منظر و شرايط محيطي، ميزان اهميت و تاثيرگذاري هر شاخص در ارزيابي مشخص مي‌شود، تا در مراحل مختلف تصميم‌گيري، برنامه‌ريزي و طراحي پروژهاي مديريت منظر و آمايش سرزمين قابل استفاده و استناد باشد.

One of the landscape dynamics that has attracted significant interest, both from the scientific community and, more recently, from the broader population, is landscape fragmentation. Landscape fragmentation has come to the forefront since it impacts ecological systems and human activities. From landscape ecology to the theory of perception, multiple disciplines have dealt with the concept and measurement of landscape fragmentation and its impacts on habitats and societies. Landscape fragmentation, which is one of the most widespread landscape processes, has been studied in both conservation biology and landscape ecology disciplines. Quantitative indicators capable of measuring landscape patterns and changes are used to examine landscape fragmentation and assess the impact on the environment and biodiversity. In addition, qualitative indicators are used to measure the social dimension and perception of landscape fragmentation by humans (with little connection to ecological processes). The present study takes a pragmatic approach to integrate existing concepts and methodologies of landscape fragmentation assessment and examine the feasibility of creating a comprehensive indicator that combines the strengths of these different perspectives. In this article, we summarize and analyze the current assessments used to study landscape fragmentation. We report the strengths, limitations, successes and challenges of the quantitative and perceptive approaches and provide an insight into the possibilities and potential of combining these approaches into one assessment. Based on the existing literature and pioneering integrative approaches, we conclude that it is convenient and feasible to design an indicator of landscape fragmentation. This indicator would be informative of changes in the landscape pattern and meaningful for land planners and society as a whole. Such an indicator, however, should be constrained in scope to focus on people and our unique perception of scale, visual fragmentation, and human societal context and cultural background. A combination of both approaches would maximize the significance and utility of a landscape fragmentation indicator. Landscape ecology methodologies have proved to be useful in developing indicators of landscape patterns. There are difficulties, however, which are inherent in the measurement methods and the interpretation of the meaning that landscape fragmentation indices have for species living in the landscape. These limitations require researchers to be very concise regarding the targeted species, the elements considered to cause the fragmentation of their habitat and the scale at which this habitat should be studied. The exact definition of which elements are involved in landscape fragmentation and the degree to which they contribute to the perception and the discrimination of groups of people that share similar views and opinions regarding a given landscape fragmentation pattern are issues that can be addressed by disciplines studying landscape perception, preferences and interactions within communities. At present, when integrative approaches combining landscape ecology indices and visual indicators have proved to be achievable, studies of the viability of particular indicators that are informative for specific landscape processes are important. Our future research will focus on the development of a suitable indicator of landscape fragmentation, which takes into account the aforementioned requirements and limitations.