Panayiotis Trigas

Bio: Panayiotis Trigas is an academic researcher from Agricultural University of Athens. The author has contributed to research in topics: Endemism & Threatened species. The author has an hindex of 13, co-authored 44 publications receiving 754 citations. Previous affiliations of Panayiotis Trigas include National and Kapodistrian University of Athens & Forest Research Institute.

Topography-driven isolation, speciation and a global increase of endemism with elevation

Abstract: Additional co-authors: Jose Maria Fernandez-Palacios, Rosalina Gabriel, Roy E. Gereau, Rosemary G. Gillespie, Josef Greimler, David E.V. Harter, Tsurng-Juhn Huang, Severin D.H. Irl , Daniel Jeanmonod, Anke Jentsch, Christoph Kueffer, Sandra Nogue, Rudiger Otto, Jonathan Price, Maria M. Romeiras, Dominique Strasberg, Tod Stuessy, Jens-Christian Svenning, Ole R. Vetaas, Carl Beierkuhnlein

Topography-driven isolation, speciation and a global increase of endemism with elevation (Forthcoming)

Abstract: Additional co-authors: Jose Maria Fernandez-Palacios, Rosalina Gabriel, Roy E. Gereau, Rosemary G. Gillespie, Josef Greimler, David E.V. Harter, Tsurng-Juhn Huang, Severin D.H. Irl , Daniel Jeanmonod, Anke Jentsch, Christoph Kueffer, Sandra Nogue, Rudiger Otto, Jonathan Price, Maria M. Romeiras, Dominique Strasberg, Tod Stuessy, Jens-Christian Svenning, Ole R. Vetaas, Carl Beierkuhnlein

Elevational Gradient of Vascular Plant Species Richness and Endemism in Crete – The Effect of Post-Isolation Mountain Uplift on a Continental Island System

Abstract: Understanding diversity patterns along environmental gradients and their underlying mechanisms is a major topic in current biodiversity research. In this study, we investigate for the first time elevational patterns of vascular plant species richness and endemism on a long-isolated continental island (Crete) that has experienced extensive post-isolation mountain uplift. We used all available data on distribution and elevational ranges of the Cretan plants to interpolate their presence between minimum and maximum elevations in 100-m elevational intervals, along the entire elevational gradient of Crete (0–2400 m). We evaluate the influence of elevation, area, mid-domain effect, elevational Rapoport effect and the post-isolation mountain uplift on plant species richness and endemism elevational patterns. Furthermore, we test the influence of the island condition and the post-isolation mountain uplift to the elevational range sizes of the Cretan plants, using the Peloponnese as a continental control area. Total species richness monotonically decreases with increasing elevation, while endemic species richness has a unimodal response to elevation showing a peak at mid-elevation intervals. Area alone explains a significant amount of variation in species richness along the elevational gradient. Mid-domain effect is not the underlying mechanism of the elevational gradient of plant species richness in Crete, and Rapoport's rule only partly explains the observed patterns. Our results are largely congruent with the post-isolation uplift of the Cretan mountains and their colonization mainly by the available lowland vascular plant species, as high-elevation specialists are almost lacking from the Cretan flora. The increase in the proportion of Cretan endemics with increasing elevation can only be regarded as a result of diversification processes towards Cretan mountains (especially mid-elevation areas), supported by elevation-driven ecological isolation. Cretan plants have experienced elevational range expansion compared to the continental control area, as a result of ecological release triggered by increased species impoverishment with increasing elevation.

Factors affecting plant species richness and endemism on land-bridge islands – An example from the East Aegean archipelago

Abstract: The native flora and a number of environmental factors were recorded for twenty islands in the eastern Aegean archipelago (Greece) in order to study the patterns of native and endemic plant species diversity as well as the effects of environmental factors in shaping these patterns at different levels of endemism. Stepwise regressions were used to test the effects of these factors on species richness of native and especially of endemic plants, at local scales. The performance of the Choros model was also compared with the separate effects of area and habitat diversity using simple linear regressions. The residuals from the species–area functions of native and endemic species were used as indices of relative island richness. Out of the 2238 species and subspecies recorded in total, 302 taxa (13.4%) are endemics (either single island endemics or endemic at a broader scale, namely Aegean, Greek-Aegean, or Anatolian–Aegean). All native, all endemic and Aegean endemic species similarities among islands were assessed and the three matrices were compared with the matrices of among-island geographical distances and island similarities based on components of habitat diversity using Mantel test. Among the factors tested, habitat diversity, of which elevation is another dimension, is the main factor affecting floral richness on east Aegean islands. The patterns exhibited by local endemics, though, are of a more idiosyncratic nature since this factor is the major predictor of species richness of most of the endemics levels (including single island endemics) except the Aegean endemics which are better predicted by elevation. The Choros model does not provide a better prediction of richness than habitat diversity alone. There is a positive correlation between native species similarities and geographical distances among islands, but no correlation between environmental and floral similarities.

Network biogeography of a complex island system: the Aegean Archipelago revisited

Abstract: Aim The Aegean Archipelago has been the focal research area for identifying and testing several ecological and evolutionary patterns, yet its biogeographical subdivision has been somewhat overlooked, with the processes driving the assembly of the Aegean island plant communities still remaining largely unclear. To bridge this gap, we identify the biogeographical modules (highly linked subgroups of islands and plant taxa) within the Aegean Archipelago. Location The Aegean Archipelago, Greece. Methods We used a network approach to detect island biogeographical roles and modules, based on a large and detailed database including 1498 Aegean endemic and subendemic plant taxa distributed on 59 Aegean Islands and five adjacent mainland areas. Results The Aegean was divided into six biogeographical modules; the network was significantly modular. None of the modules displayed all four possible biogeographical roles (connectors, module hubs, network hubs, peripherals). Six new biogeographical regions in the Aegean were identified. Main conclusions The borders of the six biogeographical regions in the Aegean correspond well to the region's palaeogeographical evolution from the middle Miocene to the end of the Pleistocene. The Central Aegean acts as an ecogeographical filter for the distribution of several plant lineages across the Aegean Sea, while there seems to be a N–S-oriented biogeographical barrier in the Aegean corresponding to the palaeogeographical situation during the middle Ionian. These biogeographical barriers have been fundamental for both plants and animals.

The Theory of Island Biogeography

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

Climate Change 2007: Impacts, Adaptation and Vulnerability.

Abstract: Impatti, adattamento e vulnerabilita Le cause e le responsabilita dei cambiamenti climatici sono state trattate sul numero di ottobre della rivista Cda. Approfondiamo l’argomento presentando il documento: “Cambiamenti climatici 2007: impatti, adattamento e vulnerabilita” votato ad aprile 2007 dal secondo gruppo di lavoro del Comitato Intergovernativo sui Cambiamenti Climatici (Intergovernmental Panel on Climate Change). Si tratta del secondo di tre documenti che compongono il quarto rapporto sui cambiamenti climatici.

Defining the Anthropocene

Abstract: Time is divided by geologists according to marked shifts in Earth's state. Recent global environmental changes suggest that Earth may have entered a new human-dominated geological epoch, the Anthropocene. Here we review the historical genesis of the idea and assess anthropogenic signatures in the geological record against the formal requirements for the recognition of a new epoch. The evidence suggests that of the various proposed dates two do appear to conform to the criteria to mark the beginning of the Anthropocene: 1610 and 1964. The formal establishment of an Anthropocene Epoch would mark a fundamental change in the relationship between humans and the Earth system.

Evolution In Changing Environments Some Theoretical Explorations

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