In the following article, there are multi methods used to test mediation. hope it help
Dardas, L., Ahmad, M. (2015). For Fathers Raising Children with Autism, Do Coping Strategies Mediate or Moderate the Relationship between Parenting Stress and Quality of Life? Research in Developmental Disabilities. 36, 620-629. http://dx.doi.org/10.1016/j.ridd.2014.10.047
In the following article, there are multi methods used to test mediation. hope it help
Dardas, L., Ahmad, M. (2015). For Fathers Raising Children with Autism, Do Coping Strategies Mediate or Moderate the Relationship between Parenting Stress and Quality of Life? Research in Developmental Disabilities. 36, 620-629. http://dx.doi.org/10.1016/j.ridd.2014.10.047
It is not compulsory to examine the mediating effects in the model if that is not one of your research objectives. From your framework, what I can see is you are only interested in analyzing the direct effects.
If you want to analyze the mediation effects, you need to estimate the direct effects as well as the indirect effects in your Amos Graphic model.
It looks like you are trying to say that "Increased value in invertebrates" is determined by willingness, interest, information and activity. You could use "increased value in invertebrates" as a latent variable and relate that to ecotourism. The simple regression of ecotourism on "increased value in invertebrates" would not involve any mediation effects since the 4 characteristics are determinants of"value in invertebrates". If you were to look at mediation, you would also draw arrows from each of the 4 characteristics to ecotourism.