Hydrological and erosional responses differed consistently between patches and inter-patches within each vegetation state.
Well vegetated patches in woody encroachment produced higher runoff than other well vegetated patches, and inter-patches in recent pasture had higher sediment concentration and production than inter-patches in other vegetation states.
Our results indicate that patches and inter-patches are functional units from an eco-hydrological perspective within this semi-arid region and they influence soil hydrological and erosional characteristics irrespective of vegetation state.
The LFA soil surface indicators, and the related NC (Nutrient Cycling) and IR (Infiltration/Runoff) indices were assessed in the observed ecological patches and inter-patches, for a total number of 157 microsites.
In our study, both intra-population epidemic dynamics (described by a specific <img src="http://journals.plos.org/plosone/article/asset?id=info?doi/10.1371/journal.pone.0009371.e425.PNG" class= inline-graphic"/> model for each patch) and inter-population spread of infection (taken into account through migration of individuals) were considered.
However, when hydrological and erosional responses from the same patch type and inter-patches were compared between vegetation states, two differences were found.
Patch area and inter-patch distances were calculated using aerial photographs (year 2000) with ArcGIS 9 software.
First, dispersal will be favoured in line with both decreasing area of habitat patches and increasing inter-patch distances.
A graph-based model of the landscape was employed where nodes represent habitat patches, edges represent inter-node paths, and inter-node distance is measured as the least-cost path according to a resistance surface.
We established small (1 m × 1 m) grazing exclosures and monitored change in herbaceous vegetation cover quarterly over 2 years, in grazed and ungrazed patches (high herbaceous vegetation cover) and inter-patches (low herbaceous vegetation cover), in woody encroachment and pasture sites in semi-arid eastern Australia.
The PFC indicator predicted a decrease in intra and inter-patch connectivity following habitat loss and fragmentation (negative change 1), whereas patch-based connectivity measures indicate an increase in connectivity between fragmented patches.
