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This page illustrates how to use the enaStructure() function to find selected structural properties of a network model.

Load the library of models and select one to use for this illustration.

load data

data(enaModels)        # load library of Ecosystem Networks
names(enaModels)       # view model names
#>   [1] "Marine Coprophagy (oyster)"              
#>   [2] "Lake Findley "                           
#>   [3] "Mirror Lake"                             
#>   [4] "Lake Wingra"                             
#>   [5] "Marion Lake"                             
#>   [6] "Cone Springs"                            
#>   [7] "Silver Springs"                          
#>   [8] "English Channel"                         
#>   [9] "Oyster Reef "                            
#>  [10] "Baie de Somme"                           
#>  [11] "Bothnian Bay"                            
#>  [12] "Bothnian Sea"                            
#>  [13] "Ythan Estuary"                           
#>  [14] "Sundarban Mangrove (virgin)"             
#>  [15] "Sundarban Mangrove (reclaimed)"          
#>  [16] "Baltic Sea"                              
#>  [17] "Ems Estuary"                             
#>  [18] "Swartkops Estuary  15"                   
#>  [19] "Southern Benguela Upwelling"             
#>  [20] "Peruvian Upwelling"                      
#>  [21] "Crystal River (control)"                 
#>  [22] "Crystal River (thermal)"                 
#>  [23] "Charca de Maspalomas Lagoon"             
#>  [24] "Northern Benguela Upwelling"             
#>  [25] "Swartkops Estuary"                       
#>  [26] "Sunday Estuary"                          
#>  [27] "Kromme Estuary"                          
#>  [28] "Okefenokee Swamp"                        
#>  [29] "Neuse Estuary (early summer 1997)"       
#>  [30] "Neuse Estuary (late summer 1997) "       
#>  [31] "Neuse Estuary (early summer 1998)"       
#>  [32] "Neuse Estuary (late summer 1998)"        
#>  [33] "Gulf of Maine"                           
#>  [34] "Georges Bank"                            
#>  [35] "Middle Atlantic Bight"                   
#>  [36] "Narragansett Bay"                        
#>  [37] "Southern New England Bight"              
#>  [38] "Chesapeake Bay"                          
#>  [39] "Mondego Estuary (Zostera sp. Meadows)"   
#>  [40] "Mdloti Estuary (C, March 2002)"          
#>  [41] "St. Marks Seagrass, site 1 (Jan.)"       
#>  [42] "St. Marks Seagrass, site 1 (Feb.)"       
#>  [43] "St. Marks Seagrass, site 2 (Jan.)"       
#>  [44] "St. Marks Seagrass, site 2 (Feb.)"       
#>  [45] "St. Marks Seagrass, site 3 (Jan.)"       
#>  [46] "St. Marks Seagrass, site 4 (Feb.)"       
#>  [47] "Sylt-Romo Bight (C)"                     
#>  [48] "Graminoids (wet)"                        
#>  [49] "Graminoids (dry)"                        
#>  [50] "Cypress (wet)"                           
#>  [51] "Cypress (dry)"                           
#>  [52] "Lake Oneida (pre-ZM)"                    
#>  [53] "Lake Oneida (post-ZM)"                   
#>  [54] "Bay of Quinte (pre-ZM)"                  
#>  [55] "Bay of Quinte (post-ZM)"                 
#>  [56] "Mangroves (wet)"                         
#>  [57] "Mangroves (dry)"                         
#>  [58] "Florida Bay (wet)"                       
#>  [59] "Florida Bay (dry)"                       
#>  [60] "Hubbard Brook (Ca)(Waide)"               
#>  [61] "Hardwood Forest, NH (Ca)"                
#>  [62] "Duglas Fir Forest, WA (Ca)"              
#>  [63] "Duglas Fir Forest, WA (K)"               
#>  [64] "Puerto Rican Rain Forest (Ca)"           
#>  [65] "Puerto Rican Rain Forest (K)"            
#>  [66] "Puerto Rican Rain Forest (Mg)"           
#>  [67] "Puerto Rican Rain Forest (Cu)"           
#>  [68] "Puerto Rican Rain Forest (Fe)"           
#>  [69] "Puerto Rican Rain Forest (Mn)"           
#>  [70] "Puerto Rican Rain Forest (Na)"           
#>  [71] "Puerto Rican Rain Forest (Sr)"           
#>  [72] "Tropical Rain Forest (N)"                
#>  [73] "Neuse River Estuary (N, AVG)"            
#>  [74] "Neuse River Estuary (N, Spring 1985)"    
#>  [75] "Neuse River Estuary (N, Summer 1985)"    
#>  [76] "Neuse River Estuary (N,  Fall 1985)"     
#>  [77] "Neuse River Estuary (N, Winter 1986)"    
#>  [78] "Neuse River Estuary (N, Spring 1986)"    
#>  [79] "Neuse River Estuary (N, Summer 1986)"    
#>  [80] "Neuse River Estuary (N, Fall 1986)"      
#>  [81] "Neuse River Estuary (N, Winter 1987)"    
#>  [82] "Neuse River Estuary (N, Spring 1987)"    
#>  [83] "Neuse River Estuary (N, Summer 1987)"    
#>  [84] "Neuse River Estuary (N, Fall 1987)"      
#>  [85] "Neuse River Estuary (N, Winter 1988)"    
#>  [86] "Neuse River Estuary (N, Spring 1988)"    
#>  [87] "Neuse River Estuary (N, Summer 1988)"    
#>  [88] "Neuse River Estuary (N, Fall 1988)"      
#>  [89] "Neuse River Estuary (N, Winter 1989)"    
#>  [90] "Cape Fear River Estuary (N, oligohaline)"
#>  [91] "Cape Fear River Estuary (N, polyhaline)" 
#>  [92] "Lake Lanier (P) Averaged"                
#>  [93] "Great Lakes (N)"                         
#>  [94] "Baltic Sea (N)"                          
#>  [95] "Chesapeake Bay (N)"                      
#>  [96] "Chesapeake Bay (P)"                      
#>  [97] "Chesapeake Bay (P, Winter)"              
#>  [98] "Chesapeake Bay (P, Spring)"              
#>  [99] "Chesapeake Bay (P, Summer)"              
#> [100] "Chesapeake Bay (P, Fall)"                
#> [101] "Sylt-Romo Bight (N)"                     
#> [102] "Sylt-Romo Bight (P)"                     
#> [103] "Beijing Urban Metabolism (C)"            
#> [104] "Vienna Urban Metabolism (C)"
NET <- enaModels[[9]]  # select the oyster NET

Next, we apply the structural network analysis.

s <- enaStructure(NET)
attributes(s)
#> $names
#> [1] "A"  "ns"

The s data object contains two objects: the adjacency matrix A and a vector of network statistics called ns.

# Adjacency matrix
show(s$A)
#>                    Filter Feeders Microbiota Meiofauna Deposit Feeders
#> Filter Feeders                  0          0         0               0
#> Microbiota                      0          0         1               1
#> Meiofauna                       0          0         0               1
#> Deposit Feeders                 0          0         0               0
#> Predators                       0          0         0               0
#> Deposited Detritus              0          1         1               1
#>                    Predators Deposited Detritus
#> Filter Feeders             1                  1
#> Microbiota                 0                  0
#> Meiofauna                  0                  1
#> Deposit Feeders            1                  1
#> Predators                  0                  1
#> Deposited Detritus         0                  0
# network stats
show(s$ns)
#>      n  L         C LD      ppr    lam1A mlam1A      rho         R        d
#> [1,] 6 12 0.3333333  2 2.147899 2.147899      1 2.147899 0.4655712 0.147899
#>      no.scc no.scc.big      pscc
#> [1,]      2          1 0.8333333