Surakarta is a city with polluted air due to transportation activities. Utilization of bioindicators could be one of efforts to monitor air pollution. Lichen is one of the air quality bioindicators that can be observed based on its morphological characteristics. This study aimed to determine air quality using lichen bioindicators at two stations in the Jebres sub-district, namely on UNS street and Juanda street. These two locations have different environmental characteristics and traffic density. This study is a descriptive exploratory research using purposive sampling method. The collected data were analyzed qualitatively based on the morphological characteristics of the lichen found. The results showed that nine species of lichen found in UNS street area, while five species of lichen in Juanda street area. Apparently, morphological character of lichen consisted of crustose, leprose, and foliose thallus types with bright thallus colour, larger diameter, and more individuals, whereas in Juanda street is crustose and leprosy with a duller color, smaller diameter, and fewer individuals. In fact, the vehicle density in the area of Juanda street was higher than UNS street area. As it is largerly known that the type and morphology are influenced by the environmental quality. Therefore, based on the founded lichen’s type and morphology, the area of Juanda street was likely more polluted than UNS street area. Our finding suported that lichen could be bioindicator for air quality.

Pepe River is one of the Bengawan Solo with a reasonably high level of water pollution due to the habit of the surroundings in throwing garbage into the river. Plants that can survive in polluted land conditions have a high tolerance level, called pioneer plants. One of them is ferns (Pteridophyta). This study aims to identify the type, abundance, Important Value Index (IVI), and index Diversity of pteridophytes plant diversity in the Pepe Watershed. The method used in this research is descriptive quantitative using the quadrat sampling technique method with a 1x1 meter plot. The sampling technique is using purposive sampling. Data analysis was conducted qualitatively and quantitatively. Analysis of diversity index data (H’) by Shannon-Wiener. Based on the results of the study found eight species of ferns from 5 families. There are Pteris vittata, Pteris biaurita L., Adiantum lunulatum Burm.fil., Adiantum latifolium Lam., Adiantum hispidulum Sw, Marsilea crenata C. Presl, Microlepia speluncae (L.) T. Moore, and Asplenium scandicinum Kaulf. This diversity is included in the medium category with H'= 1.44. The fern with the highest abundance was Pteris vittata with 176 individuals, a density of 5.87 individuals/m2, a frequency of 0.53, and an IVI of 109.3%. Set side by set, the lowest abundance was Microlepia speluncae with eight individuals, a density of 0.27 individuals/m2, a frequency of 0.03, and IVI of 5.6%. Based on this, ferns can survive in polluted river areas. Information on the diversity of ferns found on critical land, especially rivers, is expected to provide initial information in overcoming other similar critical lands.