Determining human dominance thresholds for Barrier Islands along the New Jersey coast
Creators: name: Barone, Daniel Anthony
Publisher: name: No Publisher Supplied
Year: 2016

description: Increased development and subsequent shoreline stabilization practices on barrier islands (i.e. groins, seawalls, bulkheads) suggest thresholds exist at which human dominance supersedes natural geomorphic processes. Geomorphic thresholds are defined by ratios where opposing variables (numerators and denominators) have opposing tendencies.  Determining thresholds is important because once a barrier island is human-dominated, physical dynamic processes altering the island are considered undesirable.   The research in this dissertation shows human dominance thresholds were reached for New Jersey's eight (8) developed barrier islands by 1962. This finding is based on human and physical factors of historical landscape evolution. A "Developed Barrier Island Life-Cycle"  conceptual model was used to identify stages of development along the barrier islands and define when island-scale human dominance occurs.  A Geographic Information System (GIS) was used to delineate human and physical land cover types (i.e. urban polygons, barren land polygons and wetland polygons) and additional human variable datasets (i.e. building points, road polylines, shore protection structure polylines) from aerial photographs for every decade between 1920 and 2012. Island-wide, 100m zonal analysis areas (bins) were used along the entire study area to quantify the land cover types and human variable datasets through time.  A ratio calculation was used to determine when a human dominance threshold was reached within a given bin.  Thresholds were calculated by dividing the area of urban land cover polygons (human factor) by the area of barren land and wetland polygons (physical factor).  Results were analyzed at the bin, island, and study area scales.  The distribution of human dominance in the study area was compared across the barriers located in the northern "wave-dominated"  and southern "mixed energy" geomorphic regions at the three scales to determine if geomorphic classifications influence where and when human dominance occurs.  Island mobility was calculated as the standard deviation of the total land cover area (combined urban, barren land, and wetland polygons) within every bin for each year's land cover dataset.  Results show that (1) developed barriers experience a state-change, when human activities overshadow natural processes, (2) barrier morphology and geomorphic classifications of barrier type do not dictate when and where a given section of the barrier is human dominated. Morphology of the two barrier types plays a significant role in where humans access barrier islands and when they are initially developed, (3) island mobility correlates with human dominance thresholds at various scales and determines that human agency is a more important factor than shoreline change at the local scale and (4) human dominance at the local scale can be attributed to access via railroads, while the construction of vehicular access bridges and roads induce human dominance at the island-scale.