**Preface to "Remote Sensing Applications in Monitoring of Protected Areas"**

Protected areas have been established worldwide for achieving long-term goals in conservation of nature and the associated ecosystem services and cultural values. Globally, 15% of the world's terrestrial lands and inland waters, excluding Antarctica, are designated as protected areas. About 4.12% of the global ocean and 10.2% of coastal and marine areas under national jurisdiction are set as marine protected areas. Protected lands and waters serve as the fundamental building blocks of virtually all national and international conservation strategies, supported by governments and international institutions. Some of the protected areas are the only places that contain undisturbed landscape, seascape, and ecosystems on the planet Earth. With intensified impacts from climate and environmental change, protected areas have become more important to serve as indicators of ecosystem status and functions. Earth's remaining wilderness areas are becoming increasingly important buffers against changing environmental and ecological conditions.

The development of remote sensing platforms and sensors and the improvement in science and technology provide crucial support for monitoring of protected areas across the world. Remote sensing monitoring can provide essential information for the efficient, transparent, repeatable, and defensible decision-making in managemen<sup>t</sup> and governance of protected areas. Time-series remote sensing data have allowed for reconstruction of histories of disturbances induced by anthropogenic and natural impacts. Remote sensing has unique advantages in monitoring frontier lands, which are always in remote and difficult-to-reach locations. Remote sensing technologies have profoundly changed the practice of monitoring and understanding the dynamics of protected areas and the surrounding environments. Integration of ground-based observations and remote sensing data has been practiced in monitoring the change of protected areas.

Remote sensing is among the most fascinating frontiers of science and technology that are constantly improving. Protected areas are by no means uniform entities. Protected areas have a wide range of managemen<sup>t</sup> aims and are governed by stakeholders at different administrative levels and across spatial scales. Advances in remote sensing have helped gather and share information about protected areas at unprecedented rates. There are many new and exciting remote sensing applications that contribute to better informing managemen<sup>t</sup> of protected areas. The achievements, challenges, lessons learned, and recommendations for remote sensing of protected areas deserve further attention.

The articles collected in this book reflect the subjects and contents of a published Special Issue of the open access journal *Remote Sensing* under the theme of remote sensing applications in monitoring of protected areas. We hope that this book can provide a snapshot of examples about remote sensing applications to address issues in inventory, monitoring, and managemen<sup>t</sup> of protected areas. We also hope that this book can inspire a broader scope of interests in scientific research and managemen<sup>t</sup> of protected lands and waters as the natural treasures on the planet Earth.

As the Guest Editors of the Special Issue, we appreciate the professionalism and support from all contributors, editors, and reviewers for their dedication and efforts toward the advancement of remote sensing applications in monitoring of protected areas. In particular, we express our gratitude to Ms. Sharon Fan, Section Managing Editor of the MDPI AG *Remote Sensing* Editorial Office, for her visionary suggestion in the preparation of the Special Issue and this book.

> **Yeqiao Wang, Zhong Lu, Yongwei Sheng , Yuyu Zhou** *Special Issue Editors*
