Scientists from the Climate Impacts Group, US Forest Service and US Fish and Wildlife Service collaborated to develop an automated monitoring tool that uses remote sensing and cloud computing technologies to track changes in Mexican spotted owl (Strix occidentalis lucida) nesting and roosting habitat across Arizona and New Mexico from 1986 to present. This tool provides decision-makers with up-to-date information on recent trends and current conditions, helping managers to assess drivers of habitat loss (e.g., wildfire, timber harvest, climate change), measure success of habitat restoration and land-use practices and devise management strategies accordingly to better conserve this highly threatened species. US federal agencies have used this tool to assess an overall 21 percent decline in Mexican spotted owl habitat across Arizona and New Mexico since 1986. Information provided by this tool and follow-on assessments is now being incorporated into forest management of Mexican spotted owl habitat across the region.

MONITORING TOOL

Photo: Gregory Smith, CC-by-NC-ND-2.0, via Flickr

Project Background

Landscapes are continuously changing in response to our shifting climate, natural disturbances (e.g., wildfire) and human activities (e.g., timber harvest, agriculture, urbanization). Across the southwestern United States and Mexico, Mexican spotted owl habitat is responding to these changes over time. However, monitoring the status and trends of owl habitat over such a vast extent is a major challenge. The inability to track loss and regeneration of habitat over time for this species has hindered owl forest habitat management in the region. Recently, advances in remote sensing technologies and cloudcomputing have enabled the development of automated monitoring systems that use satellite imagery and ecological modeling methods to track changes in species habitat over time.

Photo: Zion National Park

Approach

The US Forest Service and US Fish and Wildlife Service have been conducting field surveys of Mexican spotted owl nesting and roosting locations across Arizona and New Mexico since the late 1980’s. Based on those data, we trained a model to predict suitable nesting and roosting habitat across the southwestern US as a function of environmental variables derived from satellite imagery, climate data and topographic data. We performed all modeling and analysis in the Google cloud using Google Earth Engine, a powerful platform for planetary-scale spatial analysis linked to a massive cloud repository of satellite imagery and other spatial datasets. By automating the workflow in the Google cloud, this monitoring system can be run retrospectively on historical data and rerun each year as new data becomes available. An automated workflow coupled with such a capable platform enables long-term monitoring of habitat for species like the Mexican spotted owl.

Results and Findings

The automated monitoring system provides a means to track shifting patterns in Mexican spotted owl habitat over time with high accuracy. Widespread habitat gains from forest regeneration and losses due to natural and human-caused disturbances occurred every year. The broad-scale and rapid shifts in regional habitat underscores the need for continuous monitoring and the benefits of an automated workflow.

Initial findings show that across most forests in Arizona and New Mexico, there is 21 percent less Mexican spotted owl habitat in 2020 than there was in the mid-1980s. In some forests, owl habitat appears to be stable or even increasing since the early 2000’s, while in other forests, habitat has continued to decline. Trends in habitat are not uniform across the region; it has been increasing in some places and decreasing in others. Future work will explore the drivers of habitat change in the region.

Photo: Apache Sitgreaves National Forest