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Using lichen functional diversity to assess the effects of atmospheric ammonia in Mediterranean woodlands
Author(s) -
Pinho Pedro,
Dias Teresa,
Cruz Cristina,
Sim Tang Y.,
Sutton Mark A.,
MartinsLoução MariaAmélia,
Máguas Cristina,
Branquinho Cristina
Publication year - 2011
Publication title -
journal of applied ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.503
H-Index - 181
eISSN - 1365-2664
pISSN - 0021-8901
DOI - 10.1111/j.1365-2664.2011.02033.x
Subject(s) - lichen , biodiversity , ecosystem , environmental science , mediterranean climate , woodland , ecology , environmental chemistry , atmospheric sciences , geography , chemistry , biology , physics
Summary 1. Atmospheric ammonia (NH 3 ) is one of the main drivers for ecosystem changes world‐wide, including biodiversity loss. Modelling its deposition to evaluate its impact on ecosystems has been the focus of many studies. For that, universal indicators are needed to determine and compare the early effects of NH 3 across ecosystems. 2. We evaluate the effects of atmospheric NH 3 in ecosystems using lichens, which are one of the most sensitive communities at the ecosystem level. Rather than measuring total diversity, we use a functional diversity approach because this is potentially a more universal tool. 3. We evaluated the spatial and temporal patterns of atmospheric NH 3 concentrations ([NH 3 ] atm ) emitted from a point‐source over a 1‐year period in a cork oak Mediterranean woodland. We observed a temporal pattern of [NH 3 ] atm , with maximum concentrations during autumn. 4. The distribution of lichen species was c. 90% explained by [NH 3 ] atm . The tolerance of lichen species to atmospheric NH 3 , based on expert knowledge from literature, was tested for the first time against direct measurements of atmospheric NH 3 . Most species were well classified, with the exception of Lecanora albella and Chrysothrix candelaris , which were more tolerant than expected. Our updated lichen classification can be used to establish lichen functional groups that respond to atmospheric NH 3 , and these can be used in other Mediterranean countries. 5. Increasing [NH 3 ] atm led to a complete replacement of oligotrophic by nitrophytic species within 65 m of the NH 3 source. The geostatistical analysis of functional diversity variables yielded a spatial model with low non‐spatial variance, indicating that these variables can cope robustly with high spatial variation in NH 3 . 6. Synthesis and applications . Our results support the use of functional diversity variables, such as a lichen diversity value, as accurate and robust indicators of the effects of atmospheric NH 3 on ecosystems. The spatial modelling of these indicators can provide information with high spatial resolution about the effects of atmospheric NH 3 around point‐ and diffuse sources. As this methodology is based on functional groups, it can be applied to monitor both the impact of atmospheric NH 3 and the success of mitigation strategies.