Landscape Dynamics in an Iconic Watershed of Northwestern Mexico: Vegetation Condition Insights Using Landsat and PlanetScope Data

Abstract

Natural vegetation in arid and semi-arid environments of Northwestern Mexico has been subject to transformation due to extensive and intensive human occupation related mostly to primary activities. Keystone habitats such as riparian ecosystems are extremely sensitive to land use changes that occur in their surrounding landscape. In this study, we developed remote sensing-based land cover classifications and post-classification fragmentation analysis, by using data from Landsat’s moderate resolution sensors Thematic Mapper and Operational Land Imager (TM and OLI) to assess land use changes and the shift in landscape configuration in a riparian corridor of a dynamic watershed in central Sonora during the last 30 years. In addition, we derived a high spatial resolution classification (using PlanetScope-PS2 imagery) to assess the “recent state” of the riparian corridor. According to our results, riparian vegetation has increased by 40%, although only 9% of this coverage corresponds to obligate riparian species. Scrub area shows a declining trend, with a loss of more than 17,000 ha due to the expansion of mesquite and buffelgrass-dominated areas. The use of moderate resolution Landsat data was essential to register changes in vegetation cover through time, however, higher resolution PlanetScope data were fundamental for the detection of limited aerial extent classes such as obligate riparian vegetation. The unregulated development of anthropogenic activities is suggested to be the main driver of land cover change processes for arid ecosystems in this region. These results highlight the urgent need for alternative management and restoration projects in an area where there is almost a total lack of protection regulations or conservation efforts.

Resilience of riparian vegetation productivity to early 21st century drought in northern California, USA

“…Landsat satellite data have been used to monitor changes in riparian vegetation composition and productivity across a wide range of regions and timespans (Cornejo‐Denman et al, 2020; Nguyen et al, 2015; Villarreal, Van Leeuwen, et al, 2012). The continuity of Landsat satellites allows for the generation of vegetation index time series that can be analyzed with concurrent climate time series to assess vegetation sensitivity to drought and other climatic drivers (Albano et al, 2020; Zhang et al, 2021).…”

The role of habitat fragmentation in Pleistocene megafauna extinction in Eurasia

“…Mean Euclidean nearest‐neighbour distance accounts for the number of highly isolated patches, whereas aggregation index evaluates the frequency with which patch pairs occur side‐by‐side in the landscape (McGarigal et al 2012, Zatelli et al 2019). We selected these metrics as they can be successfully used to compare fragmentation among different landscapes and, in our case, different time bins (He et al 2000, Cornejo‐Denman et al 2020). These metrics were calculated for each species in each 1 ka time bin (limited to the temporal range of the species fossils), each replicated date and binarization threshold, combining all the results in a single dataset.…”

Traditional agricultural practices and their contribution to habitat quality and carbon storage in arid Northwest Mexico: a social-ecological approach in the Rio Sonora sub-watershed

“…We used the models provided by InVEST (integrated valuation of ecosystem services and tradeoffs; Sharp et al 2020) to map habitat quality and carbon storage. Both models require a land use and vegetation map as main input, which we obtained from classifications previously generated from high spatial resolution satellite data for 2018 (Cornejo-Denman et al 2020) and re-scaled at 10 meters using the nearest neighbor analysis.…”