Spatio-temporal patterns of biodiversity and their drivers [Elektronische Ressource] : method development and application / von Gerald Jurasinski

Gerald Jurasinski

Sujets

• Biologie

Informations

• Publié par: universitat_bayreuth
• Publié le: 01 janvier 2007
• Nombre de lectures: 19
• Langue: English
• Poids de l'ouvrage: 9 Mo

Extrait

Spatio-Temporal Patterns of Biodiversity and their
Drivers - Method Development and Application
Dissertation
zur Erlangung des akademischen Grades
Dr. rer. nat.
vorgelegt der
Fakultät für Biologie, Chemie und Geowissenschaften
der Universität Bayreuth
von
Herrn Dipl. Ing. Gerald Jurasinski
geb. am 24.03.1975 in Quedlinburg
Gutachter:
1. Prof. Dr. Carl Beierkuhnlein
2.
Bayreuth, den 17.April 2007Spatio-Temporal Patterns of Biodiversity and their
Drivers - Method Development and Application
By
Gerald Jurasinski
Biogeography - University of Bayreuth
GermanyThere never were in the world two opinions alike, no
more than two hairs or two grains;
the most universal quality is diversity.
Michel de MontaigneContents
Contents
Summary III
Zusammenfassung V
Organization of the thesis VII
List of Manuscripts and Publications VIII
Abbreviations XI
1 Introduction 1
1.1 Motivation 1
1.2 Background 2
1.3 Hypotheses 13
2 Conceptional and methodological contributions 16
2.1 A new terminology for biodiversity 16
2.2 Sampling spatial patterns with hexagonal grids 16
2.3 The coefficient of multi-plot similarity 16
2.4 simba - Similarity analysis for vegetation ecology 18
3 Empirical contributions 19
3.1 Spatial patterns of phytodiversity in a Mediterranean ecosystem 19
3.2 Homogenization of Alpine summits 30
4 Summarizing Discussion 32
4.1 Conceptional issues 32
4.2 Methodological issues 34
4.3 Empirical results 36
4.4 Conclusions and Outlook 40
Acknowledgements 41
References 42
IContents
Appendices 55
Appendix 1 Inventory, differentiation, and proportional diversity – a
consistent terminology for quantifying biodiversity. Oikos
(submitted) 57
Appendix 2 Hexagonal grids - an alternative for quantifying spatio-temporal
patterns of biodiversity. Journal of Biogeography (submitted) 81
Appendix 3 Measuring multi-plot similarity with presence-absence data.
Ecology (in preparation) 101
Appendix 3 Spatial patterns of biodiversity - assessing vegetation using
hexagonal grids. Proceedings of the Royal Irish Academy -
Biology and Environment (2005) 106B: 401-411 123
Appendix 4 Distance decay and non-stationarity in a semi-arid
Mediterranean Ecosystem. Journal of Vegetation Science
(submitted) 141
Appendix 5 Beyond richness - Upward shift of alpine plants leads to
homogenisation of mountain summits. Journal of Vegetation
Science (accepted) 171
Appendix 7 simba-Manual (simba - Similarity Analysis for Vegetation Ecology) 185
Appendix 8 Species list recorded through the three years of field-work in
Northeastern Morocco 236
Appendix 9 Additional information on climatic characteristics of the
Investigation Area in Northeastern Morocco 246
Appendix 10 Patterns of similarity caused by various asymmetric binary
similarity coefficients, compared to the respective ternary plots 250
Appendix 11 Curriculum Vitae Gerald Jurasinski 252
Statement 254
IISummary
Summary
In the light of land use and climate change which rapidly alter landscapes and ecosystems
worldwide there is an urgent need for standardized and comparable data in order to detect
changes of biodiversity. Therefore, it is paramount to provide methods for the comprehensive
assessment and evaluation of biodiversity. These methods are required to be representative as
well as pragmatic due to the fact, that there is insufficient time to obtain complete data sets. If
biodiversity is lost rapidly at the landscape level, frequent re-investigations have to be done in
order to detect and analyze such changes. The central objective of this thesis is the
development and evaluation of spatially explicit, widely applicable methods for the
assessment and analysis of phytodiversity, encompassing species richness as well as spatial
and temporal heterogeneity of diversity. The conceptual perspective on the one hand and the
application of the methodology in order to investigate ecological phenomena on the other
represent the two foci of the thesis.
A review of the terminology of biodiversity - especially ‘beta-diversity’ - reveals a multitude of
co-existing concepts. This plethora of definitions hampers application and scientific progress.
Thus, a new terminology is proposed, which, compared to Whittaker’s concept of diversity
(alpha, beta, gamma), provides less ambiguous terms (inventory-, differentiation-, and
proportional diversity). It enables a more direct access to the underlying ecological
phenomena and key questions. Hence, it can help to structure the scientific discussion and
future research.
Spatial patterns of diversity may be best assessed with systematic sampling. However, square
sampling grids implemented so far are exposed to the problem of distance decay and deliver
indefinite values. Therefore systematic sampling in hierarchically nested equidistant grids is
proposed as an appropriate methodology for the assessment of spatial patterns in vegetation.
A new coefficient of multi-plot similarity is developed for the analysis of pattern diversity. For
the first time this allows the calculation of similarity between one and many plots while taking
species identity into account. It performs superior to all other tested coefficients in detecting
vegetation hotspots and gradients. The multi-plot similarity coefficient provides a promising
tool for ecological research as well as for nature conservation and monitoring.
The developed equidistant sampling grid has been applied in a case study in Northeastern
Morocco to investigate the drivers of spatial patterns of biodiversity. The nested equidistant
sampling grid with hexagonal plots allows for a detailed evaluation of different aspects of
biotic diversity on landscape scale. However, while disturbances play an important role in
shaping the emergent patterns of species distribution, the long time disturbance regime,
manifested in the coarse vegetation structure, plays an even more important role. Most
notably, the relationships between spatial patterns of biodiversity and its drivers vary with
IIIscale and exhibit considerable non-stationarity. This has important implications for ecological
research. When the relation between pattern and process is under study, the sampling design
should address scale issues and enable to study the variation of the relations with scale and
extent.
The methodology developed for the comparison of multiple plots has been applied to a data
set of vegetation on Alpine summits to evaluate whether the upward shift of mountain plants
causes homogenization of the summits. The analysis reveals that this indeed is the case: The
increase in species richness on the summits is accompanied by a decrease in differentiation
diversity. In the context of this thesis it is to state, that the heterogeneity concept may provide
an interesting tool for the evaluation of actual ecological research questions as well as for
nature conservation and monitoring.
IV