diff --git a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingModel.java b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingModel.java
index cce2808d4..695295933 100644
--- a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingModel.java
+++ b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingModel.java
@@ -26,24 +26,33 @@ public class BulkUpdatingModel extends AbstractModelDecorator {
 
     protected BulkUpdatingModel(Model m) {
         super(m);
-        Graph graph = m.getGraph();
-        if (graph instanceof RDFServiceGraph) {
-            updater = new RDFServiceBulkUpdater((RDFServiceGraph)graph);
-        } else if (graph instanceof SparqlGraph) {
-            updater = new SparqlBulkUpdater((SparqlGraph)graph);
+        if (m instanceof BulkUpdatingModel) {
+            this.updater = ((BulkUpdatingModel) m).updater;
         } else {
-            updater  = null;
+            Graph graph = GraphUtils.unwrapUnionGraphs(m.getGraph());
+            if (graph instanceof RDFServiceGraph) {
+                updater = new RDFServiceBulkUpdater((RDFServiceGraph) graph);
+            } else if (graph instanceof SparqlGraph) {
+                updater = new SparqlBulkUpdater((SparqlGraph) graph);
+            } else {
+                updater = null;
+            }
         }
     }
 
-    protected BulkUpdatingModel(Model m, Graph graph) {
+    protected BulkUpdatingModel(Model m, Model baseModel) {
         super(m);
-        if (graph instanceof RDFServiceGraph) {
-            updater = new RDFServiceBulkUpdater((RDFServiceGraph)graph);
-        } else if (graph instanceof SparqlGraph) {
-            updater = new SparqlBulkUpdater((SparqlGraph)graph);
+        if (baseModel instanceof BulkUpdatingModel) {
+            this.updater = ((BulkUpdatingModel) baseModel).updater;
         } else {
-            updater  = null;
+            Graph graph = GraphUtils.unwrapUnionGraphs(baseModel.getGraph());
+            if (graph instanceof RDFServiceGraph) {
+                updater = new RDFServiceBulkUpdater((RDFServiceGraph) graph);
+            } else if (graph instanceof SparqlGraph) {
+                updater = new SparqlBulkUpdater((SparqlGraph) graph);
+            } else {
+                updater = null;
+            }
         }
     }
 
diff --git a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingOntModel.java b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingOntModel.java
index 9fb336c6d..8eb1521fe 100644
--- a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingOntModel.java
+++ b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingOntModel.java
@@ -27,24 +27,33 @@ public class BulkUpdatingOntModel extends AbstractOntModelDecorator {
 
     protected BulkUpdatingOntModel(OntModel m) {
         super(m);
-        Graph graph = m.getGraph();
-        if (graph instanceof RDFServiceGraph) {
-            updater = new RDFServiceBulkUpdater((RDFServiceGraph)graph);
-        } else if (graph instanceof SparqlGraph) {
-            updater = new SparqlBulkUpdater((SparqlGraph)graph);
+        if (m instanceof BulkUpdatingOntModel) {
+            this.updater = ((BulkUpdatingOntModel) m).updater;
         } else {
-            updater  = null;
+            Graph graph = GraphUtils.unwrapUnionGraphs(m.getGraph());
+            if (graph instanceof RDFServiceGraph) {
+                updater = new RDFServiceBulkUpdater((RDFServiceGraph) graph);
+            } else if (graph instanceof SparqlGraph) {
+                updater = new SparqlBulkUpdater((SparqlGraph) graph);
+            } else {
+                updater = null;
+            }
         }
     }
 
-    protected BulkUpdatingOntModel(OntModel m, Graph graph) {
+    protected BulkUpdatingOntModel(OntModel m, OntModel baseModel) {
         super(m);
-        if (graph instanceof RDFServiceGraph) {
-            updater = new RDFServiceBulkUpdater((RDFServiceGraph)graph);
-        } else if (graph instanceof SparqlGraph) {
-            updater = new SparqlBulkUpdater((SparqlGraph)graph);
+        if (baseModel instanceof BulkUpdatingOntModel) {
+            this.updater = ((BulkUpdatingOntModel) baseModel).updater;
         } else {
-            updater  = null;
+            Graph graph = GraphUtils.unwrapUnionGraphs(baseModel.getGraph());
+            if (graph instanceof RDFServiceGraph) {
+                updater = new RDFServiceBulkUpdater((RDFServiceGraph) graph);
+            } else if (graph instanceof SparqlGraph) {
+                updater = new SparqlBulkUpdater((SparqlGraph) graph);
+            } else {
+                updater = null;
+            }
         }
     }
 
diff --git a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/GraphUtils.java b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/GraphUtils.java
new file mode 100644
index 000000000..d681ad27b
--- /dev/null
+++ b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/GraphUtils.java
@@ -0,0 +1,21 @@
+/* $This file is distributed under the terms of the license in LICENSE$ */
+
+package edu.cornell.mannlib.vitro.webapp.rdfservice.adapters;
+
+import org.apache.jena.graph.Graph;
+import org.apache.jena.graph.compose.MultiUnion;
+
+import java.util.List;
+
+final public class GraphUtils {
+    public static Graph unwrapUnionGraphs(Graph graph) {
+        if (graph != null && graph instanceof MultiUnion) {
+            List<Graph> subGraphs = ((MultiUnion)graph).getSubGraphs();
+            if (subGraphs == null || subGraphs.isEmpty()) {
+                return ((MultiUnion)graph).getBaseGraph();
+            }
+        }
+
+        return graph;
+    }
+}
diff --git a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/VitroModelFactory.java b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/VitroModelFactory.java
index 1f15a29e9..4b5dbd2ad 100644
--- a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/VitroModelFactory.java
+++ b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/VitroModelFactory.java
@@ -4,10 +4,13 @@ package edu.cornell.mannlib.vitro.webapp.rdfservice.adapters;
 
 import static org.apache.jena.ontology.OntModelSpec.OWL_MEM;
 
+import edu.cornell.mannlib.vitro.webapp.dao.jena.RDFServiceGraph;
+import edu.cornell.mannlib.vitro.webapp.dao.jena.SparqlGraph;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 import org.apache.jena.graph.Graph;
+import org.apache.jena.graph.compose.MultiUnion;
 import org.apache.jena.graph.compose.Union;
 import org.apache.jena.ontology.OntModel;
 import org.apache.jena.ontology.impl.OntModelImpl;
@@ -17,6 +20,8 @@ import org.apache.jena.rdf.model.impl.ModelCom;
 
 import edu.cornell.mannlib.vitro.webapp.utils.logging.ToString;
 
+import java.util.List;
+
 /**
  * Make models that will do proper bulk updates.
  */
@@ -46,7 +51,7 @@ public class VitroModelFactory {
 
 		Model unionModel = ModelFactory.createModelForGraph(unionGraph);
 
-		return new BulkUpdatingModel(unionModel, baseGraph);
+		return new BulkUpdatingModel(unionModel, baseModel);
 	}
 
 	public static OntModel createUnion(OntModel baseModel, OntModel plusModel) {
@@ -58,7 +63,8 @@ public class VitroModelFactory {
 		Model unionModel = ModelFactory.createModelForGraph(unionGraph);
 		OntModel unionOntModel = ModelFactory.createOntologyModel(OWL_MEM, unionModel);
 
-		return new BulkUpdatingOntModel(unionOntModel, baseGraph);
+
+		return new BulkUpdatingOntModel(unionOntModel, baseModel);
 	}
 
 	public static Model createModelForGraph(Graph g) {