Development of an inventory practice for rare lichen species within Thousand Islands National Park

Urbanization, forest fragmentation and climate change have been accelerating the decline of many lichen species populations, especially those which are most sensitive to subtle environmental changes that disrupt ecosystem equilibrium. Due to the many specific habitat requirements of these lichens, they have shown promise as bioindicators for niche habitat areas with unique site characteristics likely important for a variety of red list species. Locating species at risk and bioindicator lichens may therefore in turn reveal areas of high ecological importance where conservation efforts should be increased. Species at risk (SAR) lichen searches are organized by Environment Canada, however efforts have been mainly limited to those with more expertise in lichenology due to the difficulty with lichen field identification as well as limitations with lichen habitat suitability models. It is proposed that the establishment of a rare lichen inventory practice in Canadian national parks would increase the search efforts for lichen species at risk as well as bioindicator species which have high potential for identifying important habitat areas for conservation and ecological integrity monitoring. A rare lichen inventory practice for Thousand Islands National Park (TINP) Resource Conservation staff was developed, focussing on rare lichen species with distribution ranges that envelope the park boundaries. Usnea sp., Lobaria pulmonaria, Physconia subpallida, Leptogium rivulare, Leptogium corticola, Teloschistes chrysophthalmus, and Heterodermia hypoleuca were selected based on their SAR status in Ontario, bioindicator potential and ease of field identification. A lichen guide was compiled, highlighting distinguishing characteristics, significant habitat features, notable Ecological Land Classifications (ELCs), chemical tests, and search tips for each selected lichen species. Calcareous soil, moist deciduous forest and older growth trees were found to be common habitat requirements for many of the selected lichen species and predictive mapping was prepared for Hill Island and Grenadier Island (two locations frequented by TINP Resource Conservation staff) to show how these features could be combined to highlight priority search areas. Hill Island and Grenadier Island were found to contain the majority of the calcareous ELC plots within the TINP boundary and therefore would make excellent preliminary inventory search areas. It is highly recommended that TINP Resource Conservation staff use the enclosed lichen guide to increase familiarity with the selected lichen species and their potential habitat areas at the beginning of each monitoring season. Periodic inventory searches should be conducted in high priority regions and any encounters with the select lichen species should be documented (species name, substrate, date, general location, GPS coordinate, photo). It is highly recommended that other national parks adopt a similar rare lichen inventory practise using customized sets of SAR and bioindicator species relevant to each region to increase overall search efforts of rare lichens, to indicate habitat areas of special interest and to contribute to the global database of rare lichen population distributions