What are the main human pressures affecting Iran’s protected areas?

More than 75% of terrestrial ecosystems are affected by human activities. To protect biodiversity, humans have created protected areas around the world. However, these areas are also not safe from human activities. In this regard, determining the degree of vulnerability of protected areas to human footprint can provide valuable information to the managers of these areas and help better protect and manage these areas. This study aims to assess the vulnerability of protected areas in Iran to human infrastructure and tries to identify the most important human activities affecting these areas. Also, this study shows how subjective selection of the zone effect of human activities affects the accuracy of the results of vulnerability assessment in four scenarios. Using multi-criteria evaluation, we examined the effects of infrastructures such as roads, railways, cities, industries, mines, and agriculture on Iran’s protected areas and increased the zone effect of these infrastructures in four scenarios. Our results showed that on average 5.1–30.3% of the extent of protected areas are affected by the negative effects of human footprints. We found that irrigated farming and roads have the most negative impact on protected areas in Iran. In addition, if the zone effect of these infrastructures reaches 10 km, more than 50% of the area of protected areas in Iran will be affected by their adverse effects. In the absence of irrigated farms and roads, the vulnerability of protected areas will be reduced from 5.1 to 1.5% and 2.6%, respectively. Our results also show that national parks and wildlife refuges were less vulnerable than protected areas. However, as the zone effect of the infrastructure increased, the national parks would become more vulnerable than wildlife refuges.