B1) Epiphyte and microhabitat diversity and function on habitat trees
Albert Reif (1), Stefanie Gärtner (2) & Diane Stevenson (1)
1) University of Freiburg, Faculty of Environment & Natural Resources, Institute of Forest Sciences, Chair of Site Classification and Vegetation Science
2) National Park Black Forest, Working Group Conservation of Processes & Development of Vegetation
Background and state of research
Habitat tree retention is currently being practiced in central Europe to provide microhabitats and conserve biodiversity(1). The long-term persistence of perennial plant structures, particularly tree stems is essential due to the slow growth of most epiphytes. Since the surface area of these structures normally exceeds that of the ground area in forests, they greatly extend the area available for colonization by plants(2).
Epiphytes are part of the floristic diversity in forests, and threatened lichens in particular depend on forest habitats(3). Forest management plays a key role in retention of suitable habitat trees and in maintaining a suitable microclimate for epiphytic lichens and bryophytes. While the role of tree species, age, size and microstructures in shaping the epiphytic community is well understood there is a lack of knowledge regarding the influence played by management history and the surrounding landscape(4).
Study questions and hypotheses
Our aim is to assess the epiphyte diversity, composition and functional response to forest management and connectivity in landscapes.
Our specific study questions and hypotheses are:
- Diversity and composition of the epiphytic community depend on the frequency and spatial distribution of:
- Quality microhabitat structures on habitat trees;
- The quality of habitat trees and the light regime within the stand; and c) habitat trees in the landscape.
- Epiphytic species can be selected as indicators for different connectivity and landscape patterns based on their response to:
- Landscape and stand management history
- Landscape-scale habitat connectivity.
Approach and methods
TG phase I involves the identification and assessment of epiphytes (lichens and bryophytes) collected from the targeted habitat trees within the 135 ConFoBi plots. We also assess one habitat tree in each of the 135 plots (micro-structures, epiphytes). In the subsequent years a subset of epiphytes and habitat tree species is selected. We aim to analyse specific indicator/umbrella species and their relationship to light (using FieldSpec, a wide resolution spectroradiometer, from B2), and also to the surrounding landscape at different scales and explain their distribution pattern using functional traits.
As predictors we use the spatially explicit stand structure data provided by A2 and the landscape information from A1 (fragmentation, heterogeneity and spatial connectivity between habitat trees). During RTG phase II microhabitats will be assessed in the field to test the accuracy of the LiDAR assessment protocol developed with A1 and A2.
We aim to develop a monitoring scheme to efficiently assess the diversity of available epiphyte microhabitats and to test its ability to provide conditions for a high diversity of epiphytes (with A1, A2). In RTG phase I B1 will provide benchmark data for epiphyte composition and diversity found on habitat trees in all study plots, which can be analysed together with other components of forest diversity (B2 to B6). Light availability measured by B2 is an important environmental factor quantifying the performance of epiphytes.
The structural assessment of the landscape for epiphytes at different scales allows us to identify the most influential affects. The required information ranges from structural characteristics of neighbouring trees (provided by A2) to the degree of landscape fragmentation (provided by A1). The empirical data produced by B1 will provide input for C1 and C2 to determine whether forest practitioners appreciate and value epiphytic diversity, and for D2 to formulate best-practice guidelines for evidence-based biodiversity management.
- Bütler, R.; Lachat, T.; Larrieu, L.; Paillet, Y. 2013: Habitat trees: key elements for forest biodiversity. In: Kraus D., Krumm F. (eds) Integrative approaches as an opportunity for the conservation of forest biodiversity. European Forest Institute, pp 84-91.
- Kriebitzsch et al. 2013: Forest-specific diversity of vascular plants, bryophytes, and lichens In: Kraus D.,Krumm F. (eds) Integrative approaches as an opportunity for the conservation of forest biodiversity. European Forest Institute, pp. 158-169.
- Hauck, M., de Bruyn, U. and Leuschner, C. 2013: Dramatic diversity losses in epiphytic lichens in temperate broad-leaved forests during the last 150 years. Biological Conservation 157: 136–145.
- Nascimbene, J.; Thor, G.; Nimis, P.L. 2013: Effect of forest management on epiphytic lichens in temperate deciduous forests of Europe – A review. Forest Ecology and Management 298: 27-38.