Monitoring Forest Change in Landscapes Under-Going Rapid Energy Development: Challenges and New Perspectives

EcoAnthromes of Alberta: An example of disturbance-informed ecological regionalization using remote sensing

Humans influence ecosystems on magnitudes that often exceed that of natural forces such as climate and geology; however, frameworks rarely include anthropogenic disturbance when delineating unique ecological regions. A critical step toward understanding, managing and monitoring human-altered ecosystems is to incorporate disturbance into ecological regionalizations. Furthermore, quantitative regionalization approaches are desirable to provide cost-effective, repeatable and statistically sound stratification for environmental monitoring. We applied a two-stage multivariate clustering technique to identify 'EcoAnthromes' across a large area - the province of Alberta, Canada - at 30 m spatial resolution, and using primarily remotely sensed inputs. The EcoAnthrome clusters represent regions with unique ecological characteristics based on a combination of natural ecological potential (e.g., climatic and edaphic factors) and disturbance, both natural and anthropogenic. Compared to existing expert-derived Natural Subregions in Alberta, the model-based EcoAnthromes showed greater class separation and explained more variance for an assortment of variables related to land cover, disturbance and species intactness. The EcoAnthromes successfully separated important ecological regions that are defined by complex assemblages of topography, climate and disturbance, such as gravel-bed river valleys, boreal forests, grasslands, post-fire recovery areas and highly disturbed agricultural, industrial and urban landscapes. In addition to presenting a flexible method for EcoAnthrome regionalization, we group and describe the EcoAnthromes created for Alberta and discuss how they can complement expert-derived regionalizations to aid in environmental management efforts, such as species recovery planning and monitoring for threatened species.

Linear infrastructure drives habitat conversion and forest fragmentation associated with Marcellus shale gas development in a forested landscape

Large, continuous forest provides critical habitat for some species of forest dependent wildlife. The rapid expansion of shale gas development within the northern Appalachians results in direct loss of such habitat at well sites, pipelines, and access roads; however the resulting habitat fragmentation surrounding such areas may be of greater importance. Previous research has suggested that infrastructure supporting gas development is the driver for habitat loss, but knowledge of what specific infrastructure affects habitat is limited by a lack of spatial tracking of infrastructure development in different land uses. We used high-resolution aerial imagery, land cover data, and well point data to quantify shale gas development across four time periods (2010, 2012, 2014, 2016), including: the number of wells permitted, drilled, and producing gas (a measure of pipeline development); land use change; and forest fragmentation on both private and public land. As of April 2016, the majority of shale gas development was located on private land (74% of constructed well pads); however, the number of wells drilled per pad was lower on private compared to public land (3.5 and 5.4, respectively). Loss of core forest was more than double on private than public land (4.3 and 2.0%, respectively), which likely results from better management practices implemented on public land. Pipelines were by far the largest contributor to the fragmentation of core forest due to shale gas development. Forecasting future land use change resulting from gas development suggests that the greatest loss of core forest will occur with pads constructed farthest from pre-existing pipelines (new pipelines must be built to connect pads) and in areas with greater amounts of core forest. To reduce future fragmentation, our results suggest new pads should be placed near pre-existing pipelines and methods to consolidate pipelines with other infrastructure should be used. Without these mitigation practices, we will continue to lose core forest as a result of new pipelines and infrastructure particularly on private land.

Choice of satellite imagery and attribution of changes to disturbance type strongly affects forest carbon balance estimates

BACKGROUND

Remote sensing products can provide regular and consistent observations of the Earth´s surface to monitor and understand the condition and change of forest ecosystems and to inform estimates of terrestrial carbon dynamics. Yet, challenges remain to select the appropriate satellite data source for ecosystem carbon monitoring. In this study we examine the impacts of three attributes of four remote sensing products derived from Landsat, Landsat-SPOT, and MODIS satellite imagery on estimates of greenhouse gas emissions and removals: (1) the spatial resolution (30 vs. 250 m), (2) the temporal resolution (annual vs. multi-year observations), and (3) the attribution of forest cover changes to disturbance types using supplementary data.

RESULTS

With a spatially-explicit version of the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3), we produced annual estimates of carbon fluxes from 2002 to 2010 over a 3.2 million ha forested region in the Yucatan Peninsula, Mexico. The cumulative carbon balance for the 9-year period differed by 30.7 million MgC (112.5 million Mg CO_2e) among the four remote sensing products used. The cumulative difference between scenarios with and without attribution of disturbance types was over 5 million Mg C for a single Landsat scene.

CONCLUSIONS

Uncertainty arising from activity data (rates of land-cover changes) can be reduced by, in order of priority, increasing spatial resolution from 250 to 30 m, obtaining annual observations of forest disturbances, and by attributing land-cover changes by disturbance type. Even missing a single year in the land-cover observations can lead to substantial errors in ecosystems with rapid forest regrowth, such as the Yucatan Peninsula.