Kostas A. Triantis

National and Kapodistrian University of Athens | uoa · Department of Ecology and Systematics

Aim We conducted the most extensive quantitative analysis yet undertaken of the form taken by the island species–area relationship (ISAR), among 20 models, to determine: (1) the best‐fit model, (2) the best‐fit model family, (3) the best‐fit ISAR shape (and presence of an asymptote), (4) system properties that may explain ISAR form, and (5) paramet...

Aim Understanding the mechanisms that generate diversity patterns requires analyses at spatial and temporal scales that are appropriate to the dispersal capacities and ecological requirements of organisms. Oceanic archipelagos provide a range of island sizes and configurations which should predictably influence colonization, diversification and ext...

Dynamics of island biodiversity Fifty years ago, MacArthur and Wilson published their influential book, The Theory of Island Biogeography . This work provided a quantitative framework for understanding the ecological processes governing the diversity of species on oceanic islands. Whittaker et al. review the subsequent progress in the field, focusi...

I am not aware of any other book that has shed so much light on species diversity patterns and generalities across time and space as has M. L. Rosenzweig’s (1995) Species diversity in space and time. Rosenzweig compared the study of species diversity patterns with a dinosaur that has come alive and is challenging us. He then listed 10 major challen...

Aim Whether entire communities of organisms converge towards predictable structural properties in similar environmental conditions remains controversial. We tested for community convergence in birds by comparing the structure of oceanic archipelago assemblages with their respective regional species pools. Location Eighteen major oceanic archipelag...

Insect declines have been reported globally but whilst island ecosystems are potentially facing exacerbated challenges, no long-term studies (LTER) have confirmed this trend. This study utilises the first available LTER data on island invertebrates, targeting epigeal and canopy arthropods from the Azores, and covering over 20 years in three distinc...

The Aegean Islands are renowned for their high diversity and endemism of terrestrial gastropods. We conducted a comparative study of the terrestrial malacofauna across many Aegean islands, spanning over 40 years. The faunal changes-such as the decrease or increase of distributions, new arrivals and extinctions-were analysed in the context of human...

ABSTRACT Motivation Human activities have been reshaping the natural world for tens of thousands of years, leading to the extinction of hundreds of bird species. Past research has provided evidence of extinction selectivity towards certain groups of species, but trait information is lacking for the majority of clades, especially for prehistoric ext...

Islands are renowned as evolutionary laboratories and support many species that are not found elsewhere1,2. Islands are also of great conservation concern, with many of their endemic species currently threatened or extinct³. Here we present a standardized checklist of all known vascular plants that occur on islands and document their geographical a...

Evolutionary radiations on oceanic archipelagos (ROAs) have long served as models for understanding evolutionary and ecological processes underlying species diversification. Yet, diversity patterns emerging from ROAs have received relatively little attention from biogeographers, even though characterizing the effect of key geo-environmental factors...

Humans have been driving a global erosion of species richness for millennia, but the consequences of past extinctions for other dimensions of biodiversity-functional and phylogenetic diversity-are poorly understood. In this work, we show that, since the Late Pleistocene, the extinction of 610 bird species has caused a disproportionate loss of the g...

Key Biodiversity Areas (KBAs) represent the largest global network of sites critical to the persistence of biodiversity, which have been identified against standardised quantitative criteria. Sites that hold very high biodiversity value or potential are given specific attention on site‐based conservation targets of the Kunming‐Montreal Global Biodi...

It has recently been proposed that the study of microbial dynamics in humans may gain insights from island biogeographical theory. Here, we test whether the diversity of the intratumoral microbiota of colorectal cancer tumors (CRC) follows a power law with tumor size akin to the island species-area relationship. We confirm a direct correlation betw...

Motivation The intrinsic characteristics of islands make them a unique study system for the investigation of ecological and evolutionary dynamics. The Mediterranean Basin, an island‐rich biodiversity hotspot, still lacks a comprehensive spatial database for these geographic features. This study presents the first comprehensive spatial database of a...

Conserving marine megafauna is a complex task, particularly due to the gaps in our knowledge regarding their distribution and susceptibility to human pressures. While the Ionian Sea, eastern Mediterranean, is renowned for hosting nesting sites for sea turtles and supporting diverse cetacean populations, identifying key marine habitats for elusive s...

Aim Island biological communities are considered to comprise non‐random assemblages from surrounding source pools, but whether they converge towards predictable structural properties remains unclear. Here, we (i) test whether insular communities of land snails converge towards similar functional and/or taxonomic properties and (ii) evaluate whether...

Biological invasions are considered a major driver of biodiversity loss, particularly on islands. Invasive alien ants can often have severe consequences on native biodiversity. Here, we review published and new information on alien ant species found on the Mediterranean island of Cyprus, a biodiversity hotspot. Our checklist of alien ants of Cyprus...

Despite the protected area expansion over the last decades, biodiversity continues to decline. The EU Biodiversity Strategy for 2030, as well as the Kunming-Montreal Global Biodiversity Framework, call for 30 % coverage by protected areas of the land and sea in order to halt and reverse biodiversity loss. Here, we use European species assessed as t...

Research on island species–area relationships (ISAR) has expanded to incorporate functional (IFDAR) and phylogenetic (IPDAR) diversity. However, relative to the ISAR, we know little about IFDARs and IPDARs, and lack synthetic global analyses of variation in form of these three categories of island diversity–area relationship (IDAR). Here, we un...

Zonites Montfort, 1810 is recorded for the first time from Paros island. As only an old shell was found, the reasons that the populations of this threatened, endemic land snail of the Aegean seem to be declining should be investigated.

Aim The world's islands support disproportionate levels of endemic avian biodiversity despite suffering numerous extinctions. While intensive recent research has focused on island bird conservation or extinction, few global syntheses have considered these factors together from the perspective of morphological trait diversity. Here, we provide a glo...

Kea is the westernmost island of the Cyclades and is located between Syros and Attica, in central Greece. In this work, we have resampled the island after 43 years – i.e. when the island was first fully sampled – and we present its complete land snail fauna. We report 42 land snail species with 10 species being new records for the island. Based on...

Islands have fascinated biologists since the days of Charles Darwin and Alfred Russel Wallace and before, providing the inspiration for substantial theoretical development that has advanced our understanding of global biodiversity patterns and the mechanisms that underpin them. As such, they are often termed 'natural laboratories', providing the id...

Land snails are one of the most diverse groups of terrestrial animals and are commonly used as model organisms in ecology, biogeography and conservation biology. Despite being poor dispersers, they form crucial components of island faunas and exhibit high percentages of endemism. Insular land snails are also among the most threatened animals on Ear...

The species–area relationship (SAR) describes a range of related phenomena that are fundamental to the study of biogeography, macroecology and community ecology. While the subject of ongoing debate for a century, surprisingly, no previous book has focused specifically on the SAR. This volume addresses this shortfall by providing a synthesis of the...

The species–area relationship (SAR) describes a range of related phenomena that are fundamental to the study of biogeography, macroecology and community ecology. While the subject of ongoing debate for a century, surprisingly, no previous book has focused specifically on the SAR. This volume addresses this shortfall by providing a synthesis of the...

Global environmental goals mandate the expansion of the protected area network to halt biodiversity loss. The European Union’s Natura 2000 network covers 27.3% of the terrestrial area of Greece, one of the highest percentages in Europe. However, the extent to which this network protects Europe’s biodiversity, especially in a biodiverse country like...

The Lichadonisia island group is located between Maliakos and the North Evian Gulf, in central Greece. Lichadonisia is one of the few volcanic island groups of Greece, consisting mainly of lava flows. Today the islands are uninhabited with high numbers of visitors, but permanent population existed for many decades in the past. Herein, we present fo...

Aim Research on the response of species richness to area and environmental heterogeneity so far has not addressed possible effects of species’ differences in ecological specialization. Herein we provide a new metric, ‘ecorichness’, in an attempt to fill this gap. Location Aegean islands (Greece). Taxon Terrestrial isopods. Methods ‘Ecorichness’...

Aim The small‐island effect (SIE) describes a different relationship between island area and species richness on smaller compared to larger islands. The pattern has recently gained widespread support. However, few studies have attempted to identify the actual mechanisms driving the SIE. Here, we use a phylogenetic community framework to study the S...

Birds are suffering from steep population declines on a global scale and they are one of the few taxonomic groups for which these declines are well documented by long-term monitoring data. This study provides a synthesis of the status of the breeding birds of Greece. To this aim, we retrieved population size estimates from six sources spanning 22 y...

Aim We tested whether species–area relationships of small islands differ among plant growth forms and whether this influences the prevalence of the small‐island effect (SIE). The SIE states that species richness on small islands is independent of island area or relates to area in a different way compared with larger islands. We investigated whether...

Analysis of a unique global data set reveals how the species diversity of birds is affected by the properties of archipelagos and offers a way to test an influential theory. Has this improved our understanding of island biodiversity patterns? Evidence from archipelagos worldwide confirms an influential theory.

Significance The island species–area relationship (ISAR) is a fundamental diversity pattern, best described by the power model. Biogeographic theory assumes predictable variation in power model parameters in relation principally to system isolation, but these assumptions are only weakly supported by previous work, which has been limited in consider...

Aims Quantifying β‐diversity (differences in the composition of communities) is central to many ecological studies. There are many β‐diversity metrics, falling mostly into two approaches: variance‐based (e.g., the Sørensen index), or diversity partitioning (e.g., additive β‐diversity). The former cannot be used when species–sites matrices are unava...

The species–area relationship (SAR) constitutes one of the most general ecological patterns globally. A number of different SAR models have been proposed. Recent work has shown that no single model universally provides the best fit to empirical SAR datasets: multiple models may be of practical and theoretical interest. However, there are no softwar...

The term meta-archipelago has been in use in cultural studies for some time, to refer to certain complex island areas in which the boundaries between conventionally recognised archipelagos are indistinct, although the concept also carries additional connotations. Use of the term in biogeography appears more recent and without effort to prescribe it...

Aim To quantify the influence of past archipelago configuration on present‐day insular biodiversity patterns, and to compare the role of long‐lasting archipelago configurations over the Pleistocene to configurations of short duration such as at the Last Glacial Maximum (LGM) and the present‐day. Location 53 volcanic oceanic islands from 12 archipe...

Overall, 695 land snail and slug species have been recorded from Greece, 59% being endemic, but these figures are expected to be quite higher. Thus, the Greek terrestrial malacofauna is the richest in Europe, with the highest level of endemics at different spatial and taxonomic scales. Greek land snails are represented by six major chorotypes. Apar...

The Aegean archipelago is a typical archipelago of continental islands which stands at the crossroads of Europe, Asia and Africa. Herein we present one of the few global studies of bioregionalization, i.e., the process of identifying, delimiting and naming biogeographical regions, based on eight animal taxa, namely ants (Formicidae), land birds, re...

Ο σπάνιος φυσικός πλούτος και η βιοποικιλότητα της χώρας μας είναι από τα υψηλότερα στην Ευρώπη και τη Μεσόγειο. Οι περιοχές στην Ελλάδα που τελούν υπό προστασία αντιστοιχούν στο 35% της χερσαίας έκτασης της χώρας και στο 1,5% της θαλάσσιας. Δομικό στοιχείο των προστατευόμε- νων περιοχών της Ελλάδας είναι οι περιοχές που ανήκουν στο Ευρωπαϊκό Οικολ...

Aim Land‐use change typically goes hand in hand with the introduction of exotic species, which mingle with indigenous species to form novel assemblages. Here, we compare the functional structure of indigenous and exotic elements of ground‐dwelling arthropod assemblages across four land‐uses of varying management intensity. Location Terceira Island...

The Aegean archipelago, comprising numerous islands and islets with great heterogeneity in topographic, geological, historical and environmental properties, offers an ideal natural laboratory for ecological and evolutionary research, and has been the stage for a very long interaction between human civilizations and local ecosystems. This work prese...

Species abundance distributions (SAD) are central to the description of diversity and have played a major role in the development of theories of biodiversity and biogeography. However, most work on species abundance distributions has focused on one single spatial scale. Here we used data on arthropods to test predictions obtained with computer simu...

The general dynamic model of oceanic island biogeography (GDM) has added a new dimension to theoretical island biogeography in recognizing that geological processes are key drivers of the evolutionary processes of diversification and extinction within remote islands. It provides a dynamic and essentially non-equilibrium framework generating novel p...

Aims The 50th anniversary of the publication of the seminal book, The Theory of Island Biogeography, by Robert H. MacArthur and Edward O. Wilson is a timely moment to review and identify key research foci that could advance island biology. Here, we take a collaborative horizon-scanning approach to identify 50 fundamental questions for the continued...

AimThe 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 bio...

Background In this contribution we present detailed distribution and abundance data for arthropod species identified during the BALA – Biodiversity of Arthropods from the Laurisilva of the Azores (1999-2004) and BALA2 projects (2010-2011) from 18 native forest fragments in seven of the nine Azorean islands (all excluding Graciosa and Corvo islands,...

Appendix 2 - Metadata from Appendix 1

Appendix 5 -Abundance data

Appendix 1 - Detailed data on the distribution and abundance of the studied species

Appendix 3 - Sites UTM coordinates

Appendix 4. Complete list of new records per island.

Since the contributions of Charles Darwin and Alfred Russel Wallace, oceanic archipelagos have played a central role in the development of biogeography. However, despite the critical influence of oceanic islands on ecological and evolutionary theory, our focus has remained limited to either the island-level of specific archipelagos or single archip...

Aim Morphological and taxonomic diversity are intuitive measures of biological diversity. Previous studies have shown discordance between these measures at large spatial and temporal scales, but the implications of this pattern for the underlying processes are not understood. Using oceanic archipelagos as spatial units, we examine potential links b...

AimThe relationship between species number and area is of fundamental importance in macroecology and conservation science, yet the implications of different means of quantitative depiction of the relationship remain contentious. We set out (1) to establish the variation in form of the relationship between two distinct methods applied to the same ha...

Background For a remote oceanic archipelago of up to 8 Myr age, the Azores have a comparatively low level of endemism. We present an analysis of phylogeographic patterns of endemic Azorean island arthropods aimed at testing patterns of diversification in relation to the ontogeny of the archipelago, in order to distinguish between alternative models...

A key challenge in island biogeography is to quantity the role of dispersal in shaping biodiversity patterns among the islands of a given archipelago. Here, we propose such a framework. Dispersal within oceanic archipelagos may be conceptualized as a spatio-temporal process dependent on: (1) the spatial distribution of islands, because the probabil...

Appendix S1. The principal data sources and summary of biological and geographical data for Hawaii, Azores and Canary Islands.

Pseudamnicola pieperi, previously known only from Karpathos Island (southeast Aegean Sea), is reported from seven new localities on Karpathos and redescribed and taxonomically circumscribed using morphological, anatomical and mtDNA sequence data. Additionally, two new species of Pseudamnicola are described from Rodos, i.e. P. ianthe and P. ilione....

Oceanic islands host a disproportionately high fraction of endangered or recently extinct endemic species. We report on species extinctions among endemic Azorean beetles following 97% habitat loss since AD 1440. We infer extinctions from historical and contemporary records and examine the influence of three predictors: geographical range, habitat s...

Recent climate projections indicate substantial environmental alterations in oceanic island regions during the 21st century, setting up profound threats to insular floras. Inherent characteristics of island species and ecosystems (e.g. small population sizes, low habitat availability, isolated evolution, low functional redundancy) cause a particula...

The study of islands as model systems has played an important role in the development of evolutionary and ecological theory. The 50th anniversary of MacArthur and Wilson's (December 1963) article, ‘An equilibrium theory of insular zoogeography’, was a recent milestone for this theme. Since 1963, island systems have provided new insights into the fo...

AimWe undertook the largest comparative study to date of the form of the island species–area relationship (ISAR) using 207 habitat island datasets and 601 true island datasets. We also undertook analyses of (a) the factors influencing z- and c-values of the power (log–log) model and (b) how z and c vary between different island types.LocationGlobal...

Significance Biogeographic theory builds upon a long history of analyzing species-diversity patterns of remote islands, but no previous studies have attempted to investigate corresponding patterns in functional traits on islands. Our analyses of functional diversity (FD) for spiders and beetles in the Azorean archipelago reveal that FD increases wi...