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Biomonitoring airborne pollution has been a widespread practice. Its advantages make it an alternative to costly technological techniques. In this context, a rare species "Urginea maritima" was tested to measure the changes surrounding Bentael natural reserve in Lebanon, triggered by the inauguration of a new road on its south side, and revealed alarming results through two years study (2015-2016). Three environmental indicators were evaluated: Air Pollution Tolerance Index, Total Antioxidant Capacity and leaf Relative Water Content. These factors showed the escalated evolution of the air pollution during the studied months. In addition, six parameters, separated between pollution markers and scavengers, were studied: hydrogen peroxide, pheophytin, proline, ascorbic acid, carotenoids and total phenolic compounds showed a gradual and sharp increase. The passive biomonitoring with plants confirmed to be a reliable method to evaluate airborne pollution effects which will expose new extent to establish a routine monitoring program in Lebanon.

The Turkey oak is a frequent tree species in the Mediterranean climate zones of southern Europe and Asia Minor. It has been used in the human diet, for medicinal purposes, firewood and charcoal production. Like all oaks, Turkey oak is suffering from dieback and decline owing to the combination of several detrimental factors, such as insects, diseases and unfavorable environment, leading to their deterioration and sometimes resulting in their early death.

Protected areas decrease degrading natural ecosystems due to pollution such as air pollution. In 1981, the inhabitants founded Bentael natural reserve in Byblos, Lebanon, to secure their region against urbanization projects, like the recently constructed road that threatens the biodiversity of the reserve. This study was conducted to determine the oxidative stress resulting from this pollution and that menaces 360 floral species among them a rare species "Urginea maritima." In this research, the biomonitoring approach was experienced to assess the oxidative stress. Biomonitoring possesses has the advantage to be low cost and a constructive method to generate valuable data for further examinations. The studied parameters were air pollutants, ascorbic acid, photosynthetic pigments, leave's pH, relative water content, proline, carbohydrates, and hydrogen peroxide, in three chosen spots, near the pollution source (P1), opposite the latter spot (P2), and in an area relatively far from the source of contamination and which was chosen as the control site (Ctrl). The results showed in P1 detection of air pollutants higher of about 80% than in Ctrl, modifications in stress markers: increased concentration of the reactive oxygen species "hydrogen peroxide," rise in the concentration of the osmoregulator amino acid "proline," and depletion in chlorophyll content, in contrast to an increase in pheophytin. All these findings can be exploited as early diagnosis of air pollution and confirmed the ability to use such biomonitor ("Urginea maritima") as a way to assess the environmental pollution levels and consequently affirm the danger of such landscape activities on natural reserves.

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