Image courtesy Dr. Joann MossaImpacts, Recovery, and Ongoing Stressors in the Apalachicola River, Florida

Speaker: Dr. Joann Mossa

Professor, Department of Geography, University of Florida

Thursday, January 23, 2019

2:50-3:50 PM (Period 8)

Turlington Hall Room 3018

University of Florida

All are welcome to attend.

The Apalachicola River has experienced impacts because of dredging for navigation and hydrologic droughts exacerbated by upstream water consumption. We review these impacts and discuss how the river is recovering following the end of dredging and the application of floodplain inundation models. Sand bars are stabilizing with vegetation since dredging ended, but ongoing impacts include erosion of dredge spoil mounds altering the adjacent channel and reduced water inputs affecting the floodplain and bay.

HERRERO, SOUTHWORTH, BUNTING, CHILD – Using Repeat Photography to Observe Vegetation Change Over Time in Gorongosa National Park


Article first published online: JUN 2017 African Studies Quarterly

ABSTRACT: Protected areas are important conservation tools, as they can be managed to preserve baseline ecosystem health, including that of vegetation dynamics. Understanding long-term ecosystem dynamics within a protected area enables one to understand how this static park landscape responds to outside pressure and changing drivers. In this study, a repeat photography analysis was used to analyze changes in the vegetation pattern and abundance at Gorongosa National Park in Mozambique across seventy-two years of the parks history. Archival photographs dating as far back as 1940 were selected for sites that could be relocated in a subsequent field visit in 2012. Qualitative and quantitative analysis on vegetation abundance by structural group was undertaken using Edwards’ Tabular Key. Results when comparing the photographic pairs show that, in general, tree cover has increased on average from 25 percent to 40 percent over the last seventy-two years. This 15 percent increase may be in response to environmental drivers such as human management, herbivory, fire, and precipitation. Contrary to many recent studies on shrub encroachment in southern Africa, this study finds an increase in tree cover. Such analysis and results are valuable in that they demonstrate long-term ecological change within a managed protected area.

Read the full publication at African Studies Quarterly


SOUTHWORTH, BUNTING, RYAN, HERRERO, WAYLENChanges in vegetation persistence across global savanna landscapes, 1982–2010

J. Southworth, L. Zhu, E. Bunting, S.J. Ryan, H. Herrero, P.R. Waylen & M.J. Hill

Article first published online: 14 Aug 2015 Journal of Land Use Science

DOI: 10.1080/1747423X.2015.1071439

ABSTRACT: We present a global analysis of the changing face of vegetation persistence in savanna ecosystems by boreal seasons. We utilized nearly 30 years of monthly normalized difference vegetation index data in an innovative time-series approach and developed associated statistical significance tests, making the application of continuous vegetation metrics both more rigorous and more useful to research. We found that 8,000,000–11,000,000 km2 of savanna have experienced significant vegetation decline during each season, while 20,000,000–23,000,000 km2 have experienced an increase in vegetation persistence during each season, relative to the baseline period (1982–1985). In addition, with the exception of the March–April–May season, which is mixed, the pattern of significant vegetation persistence in the Northern Hemisphere is almost exclusively positive, while it is negative in the Southern Hemisphere. This finding highlights the increasing vulnerability of the Southern Hemisphere savanna landscapes; either resulting from changing precipitation regimes (e.g., southern Africa) or agricultural pressures and conversions (e.g., South America).

Read the full publication at Journal of Land Use Science