The cross disciplinary approaches I have seen working in my field are integrating population, health and environmental issues, where if done on their own as has been the traditional approach, less results are achieved than when combined. Integration appears to strengthen the social and environmental impact. We are already seeing the benefits of this in a non-profit and NGO that we founded called Conservation Through Public Health. For two years we have been implementing a community based family planning program with a community based direct observation of TB treatments short course therapy (CBDOTS) program in communities with some of the highest population densities in Africa of 200 to 300 people per square kilometre and average family size of 10, bordering a national park with half the world's population of estimated 760 critically endangered mountain gorillas. We strengthen community volunteer networks who visit homes and give village health talks to conduct peer education on the benefits and methods of family planning, good hygiene and health seeking behaviour focussing on the prevention and control of infectious diseases, primarily TB, HIV/AIDS, scabies and dysentery and how it links to gorilla health, ecotourism and sustainable livelihoods. Within one year, the 28 community volunteers had visited over 1500 homes, over 500 were homes that see gorillas often, taking a message that is relevant to people's welfare and sustainable livelihoods through ecotourism. In the second year they visited 540 new homes, with 230 being new homes that often see gorillas. This resulted in 290 new family planning users in a population of 10,000, four times higher than the expected according to previous records. The volunteers also managed to identify 480 TB suspects, 11 times more than before. This method allowed resources to be combined, creating synergy and gave a platform to discuss and address issues that individually contribute to poverty reduction, but when combined are more likely to create more significant and sustained social and environmental impact.
A cross-disciplinary approach is not appropriate when you have people who are experts in their fields, but not able to understand the other fields you are trying to integrate preventing the issues from being tackled holistically, resulting in mission drift. Also if there are not enough resources to tackle the issue using a multidisciplinary approach there is a danger of spreading oneself thin, and not having the desired impact. Cross-disciplinary approaches often require a lot of cross-sectoral sensitization about the benefits to all stakeholders before starting to ensure the desired outcomes.