Query Summary

Summary of query specifications, statistics of extracted data and maps of the extent and coverage of the selected habitat preferences.


                  

                

              

            

            

              

                

                  
Dispersal Probability Maps

                  
Map showing the 'Downstream' (export) or the 'Upstream' (import) dispersal probability from/to the selected port: 

                  

                    Note: Some ports appear twice (i.e. xxx1, xxx2). This represent alternative locations in the 10km grid when the port i located
                               at or near a boundary between two adjacent 10km grids, or where a 10km grid has a high land coverage
                  

                  

                    
                    

                      
                      
                    

                  

                  

                    
                    
                  

                  

                    
                    
                  

                  

                    
                    

                      
                      
                    

                  

                  
Select '1' generation to reflect the direct dispersal, and 
                            '2' generations to reflect potential stepping-stone dispersal.
                            Recruitment rate (0-1) represents the theoretical proportion of
                            settled propagules that contribute to the 2nd generation dispersal:

                  

                    
                    

                      
                      
                    

                  

                  

                    
                    
                  

                  
                  
                    
                  
                  

                  

                  

                  
                

                

                  

                

              

              
            

            

              

                

                  
Port Connectivity Matrix

                  
Select minimum 2 ports from the list to generate a matrix
                            showing pairwise dispersal connectivity probabilities between ports:

                  

                    
                    

                      
                      
                    

                  

                  
Select '1' generation to reflect the direct disperal, and 
                            '2' generations to reflect potential stepping-stone dispersal.
                            Recruitment rate (0-1) represents the theoretical proportion of
                            settled propagules that contribute to the 2nd generation dispersal:

                  

                    
                    

                      
                      
                    

                  

                  

                    
                    
                  

                  
                

                

                  

                

              

            

            

              
Cluster Analysis

              

                

                  
Cluster analyses are used to identify groups of sub-areas in a network

                          (i.e. 10 km grids) that are more strongly connected than to the rest of the system.
                   Boundaries between clusters can sometimes be interpreted as dispersal barriers allowing

                   limited or no dispersal between the clusters in 
                   one or both directions. Two cluster algorithms are included. Louvain (assuming an undirected network) and Infomap (assuming a directional network.)

                  

                    
                    

                      
                      
                    

                  

                  

                    

                      

                        
                        
                      

                    

                    

                      

                        
                        
                      

                    

                  

                  
                  

                  

                  

                  

                  

                  

                  
                  

                    Values in the cluster (colored polygons) centroids (circles) indicate the
                          local retention of each cluster in % of total no. of spawned probagules

                          inside the cluster (Default) or in % of total no. of spawned 
                          proabagules that successfully settle inside suitable habitats (Optional), i.e. excluding unsuccessful settlers
                          outside habitat preferences.)
                          The thicknesses of arrows represent the relative strength of export of
                          agents between clusters, relative to the agent export of each cluster. 
                          An upper threshold for arrow thickness was set to 10%
                  

                

                

                  

                

              

            

            

              
Sink/Source Maps

              

                

                  
Sink and source areas can be mapped using the metrics from Graph Theory named 'In- and Out-degree' and 'In- and Out-Strength.

                  

                  

                    In-degree
                     - is the number of nodes (i.e. 10km grid) each node recieves agents from.
                  

                  

                    Out-degree
                     - is the number of nodes (i.e. 10km grid) each node donates agents to.
                  

                  

                    In-strength
                     - is the weighted number of nodes (i.e. 10km grid) each node recieves agents from, .
                  

                  

                    Out-strength
                     - is the weighted number of nodes (i.e. 10km grid) each node donates agents to.
                  

                  
For In-strength and out-strength each connection is weighted by the number of agents the connection is represented by.

                  

                    
                    

                      
                      
                    

                  

                  
                  

                  

                  

                  

                  

                  

                    Note: In-strength values are normalised to show each node’s share (0–1) of total network imports, so 0.015 equals 1.5% of all imports.
                          Out-strength values are normalised likewise, representing each node’s share (0-1) of total exports, where 0.015 equals 1.5% of all exports.
                  

                

                

                  

                

              

            

            

              

                

                  
                  
Spatial extent of the connectivity database. 
                                     Grid represents a subdivision (10x10 km) of the area for calculating
                                     connectivity matrices. Red lines indicate EEZ boundaries.
                                     Back-ground bathymetry data from IOC, IHO and BODC (2003)

                

                

                  
About this tool

                  
This tool is designed to predict the risk of natural dispersal and connectivity of pelagic lifestages of benthic marine 
                     non-indigenous species in the transboundary marine and brackish waters of Denmark, Sweden and Germany.

                  

                    The methodology is based on: 
                    Hansen et al. (2024)
                    .
                  

                  
In the left panel species specific traits must be selected:

                  

                        1. Select a connectivity database
                  

                  

                        2. Select dispersal traits
                  

                  

                        3. Select habitat preferences
                  

                  

                        4. Run Query
                  

                  

                  

                  
QUERYING

                  

                  
The query extracts one connectivity matrix for each combination of spawning date, pelagic larval duration, year, and drift scenario.
                     
                     Each matrix is derived from a biophysical simulation of approximately 100,000 agents randomly distributed across the model domain at the time of spawning.
                     
                     During processing, matrices are filtered to remove connections outside larval salinity thresholds and aggregated into a single connectivity matrix.
                     
                     The final matrix is further filtered to retain only connections consistent with habitat preferences, including seabed substrate, water depth, and seabed salinity.

                  

                  
ANALYSES

                  
Query outputs, including matrix statistics and resulting habitat maps, are presented in the “Query summary” tab.
                       Matrix analyses and associated plots are available in individual tabs, along with relevant metadata and information.

                  

                  

                    For more details see 
                    MCDB documentation
                    .
                  

                  

                  
FUNDING

                  
This work has been funded by the Danish Maritime Fund and the Danisgh Ministry of Higher Education and Science

                  

                  

                  
Contact:   Flemming Thorjørn Hansen, flth@dhigroup.com

                  

                  
Cite as: 

                  
Hansen FT (2025) Marine Connectivity Explorer. [Shiny web applicaion] https://marineconnectivity.dhigroup.com/, DHI A/S, (accessed YYYY-MM-DD)

                  

                  

                  
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