3.3. Comparison of classifications for Mediterranean non-perennial rivers and streams
The alluvial diagram for Mediterranean NPRS reveals differences between MATTM, IPH and LIFE+ TRivers hydrotypes classifications and the three clusters obtained in this study (Fig. 5). Cluster I is represented by 9% of the stations, compared to 41% in cluster II and 51% in cluster III regarding our SOM classification. Using the MATTM classification, most stations are intermittent rivers (87%), followed by ephemeral (10%) and episodic (3%). Using the IPH classification, most are temporal (62%), followed by intermittent (35%) and ephemeral (3%). Applying the hydrotypes of the LIFE+ TRivers project, 19% of the stations are of episodic type, 1% of intermittent-dry, 61% of intermittent-pools, and 19% of perennial.
(Here Fig. 5)
Additionally, figure 6 shows the relationships between the categories of the different classifications. Cluster I is composed of equal parts (33%) of ephemeral, episodic and intermittent rivers, cluster II by ephemeral (18%) and intermittent (82%) and cluster III only by intermittent (100%) in MATTM classification. Similarly, cluster I is represented by ephemeral (33%), intermittent (50%), and temporal (17%); cluster II by intermittent (75%), and temporal (25%) and cluster III only by temporal (100%) rivers in the IPH classification. Besides, cluster I is mainly represented by episodic hydrotypes (33%), intermittent-dry (17%), and intermittent-pools (50%), cluster II by episodic (25%), intermittent-pools (71%), and perennial (4%), and cluster III by episodic, intermittent-pools, and perennial (11, 54, and 34%, respectively). Also, 100% of episodic and ephemeral rivers on MATTM are ephemeral and intermittent rivers on IPH, respectively. In contrast intermittent rivers of the MATTM are intermittent (29%) or temporal (71%) in IPH classification. Moreover, 100% of the episodic type of MATTM are also episodic of hydrotype classification, but varies for the rest of the types due to the ephemeral rivers on MATTM may be episodic (29%), intermittent-dry (14%) or intermittent-pools (57%) and intermittent rivers on MATTM may be episodic (15%), intermittent-pools (63%) or perennial rivers (22%). Finally, 100% of the ephemeral type of IPH is also episodic of hydrotypes TRivers classification. However, intermittent types are 25% episodic-type, 4% intermittent-dry, 70% intermittent-pools versus temporal types that are 12% episodic-type, 58% intermittent-pools, and 30% perennial.
(Here Fig. 6)