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Landscape structure in the Eastern US experienced great changes in the last century with the expansion of forest cover into abandoned agricultural land and the clearing of secondary forest cover for urban development. In this paper, the spatial and temporal patterns of forest cover from 1914 to 2004 in the Gwynns Falls watershed in Baltimore, Maryland were quantified from historic maps and aerial photographs. Using a database of forest patches from six times—1914, 1938, 1957, 1971, 1999, and 2004—we found that forest cover changed, both temporally and spatially. While total forest area remained essentially constant, turnover in forest cover was very substantial. Less than 20% of initial forest cover remained unchanged. Forest cover became increasingly fragmented as the number, size, shape, and spatial distribution of forest patches within the watershed changed greatly. Forest patch change was also analyzed within 3-km distance bands extending from the urban core to the more suburban end of the watershed. This analysis showed that, over time, the location of high rates of forest cover change shifted from urban to suburban bands which coincides with the spatial shift of urbanization. Forest cover tended to be more stable in and near the urban center, whereas forest cover changed more in areas where urbanization was still in process. These results may have critical implications for the ecological functioning of forest patches and underscore the need to integrate multi-temporal data layers to investigate the spatial pattern of forest cover and the temporal variations of that spatial pattern. Zhou, W., G. Huang, S. T. A. Pickett, and M. L. Cadenasso. 2011. 90 Years of Forest Cover Change in an Urbanizing Watershed: Spatial and Temporal Dynamics. Landscape Ecology 26:645–659. https://doi.org/10.1007/s10980-011-9589-z.
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This content will become publicly available on March 1, 2026
Structural and Functional Connectivity of Thermal Refuges in a Desert City: Impacts of Climate Change and Urbanization on Desert Wildlife
Connectivity is crucial for species conservation, but most assessments define connectivity solely in terms of protected or natural areas and land covers without regard for the underlying thermal environment. As climate change accelerates, it is becoming increasingly important to not only assess land use and land cover changes (LULCC) but also how surface temperatures are evolving and creating more fragmented thermal refuges over time. This research investigates how the surface thermal environment has changed over time in Phoenix, Arizona, USA, a desert city in the southwestern United States, and how the spatial patterns of cooler refuges within the heat landscape, or “heatscape,” may be affecting wildlife habitat availability alongside LULCC. We quantify the structural and functional connectivity of thermal refuges using a suite of connectivity metrics from landscape ecology to demonstrate how the spatial distribution and configuration of these critical areas has changed over the last 35 years and what the implications are for the many wildlife species living in this desert environment. Results show that thermal refuge patches have been shrinking and becoming more fragmented over the past 35 years, with connectivity also declining over the same period. A key inflection point was identified in 2000, when the probability that cooler refuges patches were connected dropped to nearly zero, and it has remained at that low level ever since. These shifts in connectivity are tightly coupled with LULCC in the study area, particularly the loss of irrigated agriculture as it has been replaced by residential and other developed land uses over time. Decreasing water security in the region also threatens to reduce the availability of cooler patches and, simultaneously, the connectivity of those refuges. Introducing cooler patches through engineered materials or artificial shade may help offset some of the losses from irrigated lands. The findings offer a perspective for conservation research with implications for advancing a more formal thermal landscape ecology for understanding and improving the relationship between spatial thermal patterns and ecological processes.
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- Award ID(s):
- 2416164
- PAR ID:
- 10617958
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Land
- Volume:
- 14
- Issue:
- 3
- ISSN:
- 2073-445X
- Page Range / eLocation ID:
- 480
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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