Date of Award

2007

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Dr.Salem Essa

Second Advisor

Dr.Tarek Yousef

Third Advisor

JamesFleteher

Abstract

High resolution digital aerial photographs were used to rate the change and to evaluate the woody Prosopis juliflora dynamics in northern UAE, Filayah (untreated) and Khut (treated). A time series of three different dates: 1986, 1996, and 2005 were chosen. Onscreen digitizing of plant communities was conducted using interpretative elements such as shape, tone texture, shadow and final maps were produced with acceptable accuracy. A geodatabase was built for both sites containing layers representing different dates. Statistical analysis was performed to rate the changes of the following four spatial attributes: percent cover, patch density, patch size, and mean patch shape index. GIS Overlay analysis was conducted to visualize plant dynamics and find possible spatial associations.

Results showed that Prosopis juliflora represents a real threat to the local native species, as its percent cover increased during 19-years study period (1986-2005), from 10.48 to 16.17% in Filayah area, and from 1.19 to 32.48% in Khut area. Furthermore, patch density was also continuously increasing during the study period as it increased from 2.8 to 5.96 patch/ha for Filayah area, and from 1.58 to 25.05 patch/ha in Khut area during the same period.

It seems that P. juliflora goes through phases of expansion. First, an accelerated expansion earlier in the establishment period, and then the distribution reaches a plateau. This plateau may be an optimum density of P. juliflora in that region. The time period for such optimum is suggested to be around 10 years from invasion.

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