"Forests are a considerable source of biodiversity and, as such, are inextricably linked to people's food security, nutrition and health in a number of fundamental ways." -International Forestry Review

The many links between nature and food security are so complex that they often go unnoticed. Many believe that natural spaces have ceased to be important to food security. Therefore protection of them, and the multiple ecosystem services and functions (ESSF) they provide, often takes a backseat to agricultural production. - However, biodiversity does contribute to nourishing people around the world. Roughly one billion people are reliant on wild harvested products which adds not only considerable calories but also much needed protein and micronutrients. This is true of both urban and rural populations (e.g. 4.5 million tons of bushmeat a year comes from the Congo Basin). Even ESSF direct contribution to food is not as important as inputs to agricultural production e.g. regulation of water flow and quality, provision of pollination services, maintenance of nutrient cycling and soil fertility, mitigation of climatic extremes, control of agricultural pests and diseases.

ESSF is complex and dynamic and therefore difficult to understand. For our entire existence we have nourished ourselves directly from the bounty of forests, grasslands and other wild places. Our existence and theirs is a symbiosis of complex interactions. A simplified version of this interaction is obvious: what we exhale and excrete is nourishment for the wild places; wild places in turn produce food, clean water and oxygen. The relationship includes deep connections, spirituality, cultural diversity, and many other resources, services, knowledge. The diversity of ESSF is also one reason why natures crucial role in food security goes unappreciated.
We have forgotten that these wild places are still nourishing us and that we should respect and nourish them.
I think of it as 'use it or lose it'. I also know that 'we will not fight for what we do not love' and that the cultural importance of native species has lead to much of the activism for environmental conservation.
So much of the critical conservation enacted in our world happens invisibly and is carried out by people without degrees or professional titles; while most of the resources go to environmental groups who are well-intentioned and well-staffed but rarely have the extensive site-based knowledge. What we need is a movement. This must be based on research with inquiries linking the use of biodiversity and the conservation of it through well managed (sustainable, holistic) utilization of native species.
A special issue of the International Forestry Review on "Forests, Biodiversity, and Food Security" is taking a step toward rectifying these knowledge gaps through multidisciplinary and international studies that focus on a variety of approaches and perspectives, as well as a wealth of data and analysis on the question of what forests contribute to food security, nutrition, and human wellbeing. It suggests the answer lies again in diversity: a diversity of approaches, perspectives, methods, and tools.
http://www.ecofilms.com.au is part of the DVD title "Establishing a Food Forest" with Permaculture teacher Geoff Lawton from a trip he made in Vietnam a while back to visit a 300 year old Food Forest built on 2 acres of land and still functioning well in the same family 28 generations later. More info:
http://www.ecofilms.com.au/ (more on diversity and genetic resources maintained in Vietnamese Home gardens, in: Agrobiodiversity conservation and development in Vietnamese home gardens, Agricultural Ecosystems and Environment 2033. and Vietnamese Home Gardens, Cultural and Crop Diversity in Home Gardens and Agrobiodiversity)