How do networks vary among southern, middle, and northern ranges?

Here I assigned the sites to subspecies ranges based on visual inspection of the USDA plants database. I reduced the number of samples to the 21 most northern (7 sites) for comparison to the southern subspecies dataset. A middle range was selected by measuring the geographic distance between the southern and northern sites and choosing the seven sites closest to the middle. The top taxa are selected to facilitate comparison of networks among regions.

Plots of the networks by geographic location and taxonomic level

Network characteristics

Betweenness centrality

Clustering Coefficient

Error bars indicate the mean and SD of Erdős–Rényi random graphs.

Average path length

Error bars indicate the mean and SD of Erdős–Rényi random graphs.

Modularity

Error bars indicate the mean and SD of Erdős–Rényi random graphs.

Mean degree

Compare with random network

Testing if networks have scale-free property (follow a power law)

A significant p-value indicates that the network does NOT follow a power law.

## [1] 0.2024387
## [1] 0.9993607
## [1] 0.9699989
## [1] 0.1008881
## [1] 0.9999772
## [1] 0.9998766
## [1] 0.9998936
## [1] 0.9985804
## [1] 1

These results provide no evidence to reject the null hypothesis that the networks do not follow a power law.

##       smallworldness         trans_target averagelength_target 
##                  NaN            0.6545072                  Inf 
##          trans_rnd_M         trans_rnd_lo         trans_rnd_up 
##            0.1563375            0.1436928            0.1705989 
##  averagelength_rnd_M averagelength_rnd_lo averagelength_rnd_up 
##                  Inf                  Inf                  Inf