Association between cacti and nurse plants: a quantitative literature review

The association between cacti and nurse plants has been reviewed by different authors. These reviews however were qualitative because only evaluated aspects such as species identity of cacti and nurse plants, probable explanatory causes of their association, and location of study sites. To our knowledge, there are no quantitative reviews that have evaluated the association between cacti and nurse plants for different subfamilies, tribes, and growth forms of cacti and nurse plants, and different plant communities and soil properties. To address these issues, we performed a quantitative review of the studies on the association between cacti and nurse plants. The studies were searched in the ISI Web of Knowledge from 1986 to 2021. Data obtained from studies were analyzed with the relative risk ratio and ratio of medians. Most studies on the association between cacti and nurse plants were performed mainly in Mexico and the USA. Globose, cylindrical, and columnar cacti of the subfamily Cactoideae, and tribes Cacteae, Cereeae, and Echinocereeae were associated to nurse plants of Asteraceae, Euphorbiaceae, and Fabaceae. However, other subfamilies (Opuntioideae) and tribes (Notocacteae) of cacti, and families (Asparagaceae) of nurse plants were not associated. Nurse plants ameliorated temperature, moisture, and nitrogen of soil. The association between cacti and nurse plants occurred in desert shrubland and tropical dry forest. Further studies are needed on the association between cacti and nurse plants that consider more cactus subfamilies and tribes in countries with high cactus diversity in Central and South America.