Differing avian connections to a semi-arid ecosystem

In this study we analyzed the scalar effects of vegetation coverage on avian density across the CAP LTER study region, encompassing desert and urban ecosystems.  We expect based on our preliminary work that there is a specific scale that birds are more likely to exploit vegetation abundance.  Bird diversity and density were surveyed at 40 sites quarterly during 2003.  We compiled overall bird count estimates in order to estimate general avian density.  Buffers were constructed to around these points, each with increasing radius of 0.5km.  Within these buffers, vegetation coverage was extracted by an object-oriented remote sensing classification scheme conducted on high-resolution (0.6m ²) aerial photography captured in April 2003.  This classification was subset at a variety of scales in order to determine which scale of vegetation best determines avian density.  Findings from the analysis suggest: (1) there is a significant relationship between vegetation coverage and avian density at all scales and; (2) birds react to vegetation coverage at localized more so than regionalized scales.