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

The Theory of Island Biogeography

Statistical method for testing the neutral mutation hypothesis by DNA polymorphism.

What is ecological speciation

Climate change in the past has led to significant changes in species' distributions. However, how individual species respond to climate change depends largely on their adaptations and environmental tolerances. In the Quaternary, temperate-adapted taxa are in general confined to refugia during glacials while cold-adapted taxa are in refugia during interglacials. In the Northern Hemisphere, evidence appears to be mounting that in addition to traditional southern refugia for temperate species, cryptic refugia existed in the North during glacials. Equivalent cryptic southern refugia, to the south of the more conventional high-latitude polar refugia, exist in montane areas during periods of warm climate, such as the current interglacial. There is also a continental/oceanic longitudinal gradient, which should be included in a more complete consideration of the interaction between species ranges and climates. Overall, it seems clear that there is large variation in both the size of refugia and the duration during which species are confined to them. This has implications for the role of refugia in the evolution of species and their genetic diversity.

https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2009.1272

Refugia revisited: individualistic responses of species in space and time

Pollinators may be declining globally, a matter of concern because animal pollination is required by most of the world's plant species, including many crop plants. Human land use and the loss of native habitats is thought to be an important driver of decline for wild, native pollinators, yet the findings of published studies on this topic have never been quantitatively synthesized. Here we use meta-analysis to synthesize the literature on how bees, the most important group of pollinators, are affected by human disturbances such as habitat loss, grazing, logging, and agriculture. We obtained 130 effect sizes from 54 published studies recording bee abundance and/or species richness as a function of human disturbance. Both bee abundance and species richness were significantly, negatively affected by disturbance. However, the magnitude of the effects was not large. Furthermore, the only disturbance type showing a significant negative effect, habitat loss and fragmentation, was statistically significant only in systems where very little natural habitat remains. Therefore, it would be premature to draw conclusions about habitat loss having caused global pollinator decline without first assessing the extent to which the existing studies represent the status of global ecosystems. Future pollinator declines seem likely given forecasts of increasing land-use change.

https://esajournals.onlinelibrary.wiley.com/doi/epdf/10.1890/08-1245.1

A meta‐analysis of bees' responses to anthropogenic disturbance

Worldwide ancient lakes have been a major focal point of geological, biological, and ecological research, and key concepts in, for example, evolutionary biology are partly based on ancient lake studies. Ancient lakes can be found on most continents and climate zones with most actual or putative ancient lakes in Europe being restricted to the Balkan Region. The arguably most outstanding of them is the oligotrophic and karstic Lake Ohrid, a steep-sided graben of rift formation origin situated in the central Balkans. Here, an attempt is made to summarize current knowledge of the geological, limnological, and faunal history of Lake Ohrid. Additionally, existing data on biodiversity and endemism in Lake Ohrid are updated and evaluated, and patterns and processes of speciation are reviewed in the context of the Ohrid watershed, including its sister lake, Lake Prespa. Whereas the geological history of the Ohrid Graben is relatively well studied, there is little knowledge about the limnological and biotic history of the actual lake (e.g., the age of the extant lake or from where the lake first received its water, along with its first biota). Most workers agree on a time frame of origin for Lake Ohrid of 2–5 million years ago (Mya). However, until now, the exact limnological origin and the origin of faunal or floral elements of Lake Ohrid remain uncertain. Two largely contrasting opinions either favour the theory of de novo formation of Lake Ohrid in a dry polje with a spring or river hydrography or a palaeogeographical connection of Lake Ohrid to brackish waters on the Balkan Peninsula. Whereas neither theory can be rejected at this point, the data summarized in the current review support the de novo hypothesis. An assessment of the fauna and flora of Lake Ohrid confirms that the lake harbours an incredible endemic biodiversity. Despite the fact that some biotic groups are poorly studied or not studied at all, approximately 1,200 native species are known from the lake, including 586 animals, and at least 212 species are endemic, including 182 animals. The adjusted rate of endemicity is estimated at 36% for all taxa and 34% for Animalia. In terms of endemic biodiversity, Lake Ohrid is with these 212 known endemic species and a surface area of 358 km2 probably the most diverse lake in the world, taking surface area into account. Preliminary phylogeographical analyses of endemic Lake Ohrid taxa indicate that the vast majority of respective sister taxa occurs in the Balkans and that therefore the most recent common ancestors of Ohrid- and non-Ohrid species likely resided in the region when Lake Ohrid came into existence. These data also indicate that there is relatively little faunal exchange and overlap between Lake Ohrid and its sister lake, Lake Prespa, despite the fact that the latter lake is a major water supplier for Lake Ohrid. Studies on selected species flocks and scatters, mostly in molluscs, point towards the assumption that only few lineages originally colonized Lake Ohrid from the Balkans and that the majority of endemic species seen today probably started to evolve within the lake during the early Pleistocene. Within the Ohrid watershed, endemism occurs at different spatial and taxonomic scales, ranging from species endemic to certain parts of Lake Ohrid to species endemic to the whole watershed and from subspecies to genus level and possibly beyond. Modes of speciation in the Ohrid watershed are largely affected by its degree of isolation. Observational evidence points towards both allopatric (peripatric) and parapatric speciation. Though sympatric speciation within a habitat is conceivable, so far there are no known examples. Today, the lake suffers from increasing anthropogenic pressure and a “creeping biodiversity crisis”. Some endemic species presumably have already gone extinct, and there are also indications of invasive species penetrating Lake Ohrid. The comparatively small size of Lake Ohrid and the extremely small range of many endemic species, together with increasing human pressure make its fauna particularly vulnerable. It is thus hoped that this review will encourage future research on the ecology and evolutionary biology of the lake’s taxa, the knowledge of which would ultimately help protecting this unique European biodiversity hot spot.

Ancient Lake Ohrid: biodiversity and evolution

Biologists have used a wide range of organisms to study the origin of taxa and their subsequent evolutionary change in space and time. One commonly used tool is the molecular clock approach, relating substitution rates of nucleotide or amino acid sequences to divergence times. The accuracy of the molecular clock, however, has long been subject to controversy, and numerous papers have addressed problems associated with estimating divergence times. Some workers pointed out a striking imbalance between sophisticated software algorithms used for molecular clock analyses on the one hand, and the poor data on the other hand. Moreover, there is often unease among workers relative to molecular clocks because of the controversy surrounding the approach, the complex mathematical background of many molecular clock tools, the still limited number of available, user-friendly software packages, the often confusing terminology of molecular clock approaches, and the general lack of reliable calibration points and/or external clock rates. The current review therefore briefl y provides an overview of analytical strategies, covering approaches based on calibration points and/or bounds, approaches based on external clock rates, and approaches that attempt to estimate relative divergence times in the absence of information that can be used for estimating substitution rates. It also deals with major problems and pitfalls associated with data and analyses, including potential errors of calibration points and bounds, the performance of the gene(s) used, estimation of confi dence limits, and misinterpretation of the results of clock analyses due to problems with sampling design. A substantial part of the review addresses the question of "universal" molecular clock rates and summarizes important biological and life history variables that account for deviations from rate constancy both between lineages and at different times within lineages. The usefulness of these factors is discussed within the framework of "trait-specifimolecular clock rates. One such clock rate is introduced here for the cytochrome c oxidase subunit I (COI) gene in small dioecious, tropical and subtropical Protostomia with a generation time of approximately one year. A fl ow chart is provided as a "simple fool's guide" to molecular clock analyses, together with a glossary of widely used terms in molecular clock approaches. Finally, step-by-step examples are provided for calculating divergence times in the caenogastropod subfamily Pyrgulinae based on both an internal calibration point and a "trait-specifi c" molecular clock rate, and it is demonstrated how a relative clock approach can be used for testing evolutionary hypotheses. Our review encourages a judicious use of molecular clock analyses in evolutionary studies of invertebrates by demonstrating their great potential on the one hand and (often-manageable) problems and pitfalls on the other hand.

https://bioone.org/journals/american-malacological-bulletin/volume-27/issue-1_2f_2/006.027.0203/As-Time-Goes-by--A-Simple-Fools-Guide-to/10.4003/006.027.0203.pdf

As Time Goes by: A Simple Fool's Guide to Molecular Clock Approaches in Invertebrates*

Is deep-water gastropod decline in the ancient lakes Malawi and Tanganyika heralding ecosystem change ?

Phylogenetic relationships and evolution of pulmonate gastropods (Mollusca): new insights from increased taxon sampling.

Sulawesi, the largest island in the Indonesian biodiversity hotspot region Wallacea, hosts a diverse endemic fauna whose origin has been debated for more than 150 years. We use a comparative approach based on dated phylogenies and geological constraints to test the role of vicariance versus dispersal in the origin of Sulawesi taxa. Most divergence time estimates for the split of Sulawesi lineages from their sister groups postdate relevant tectonic vicariant events, suggesting that the island was predominantly colonized by dispersal. Vicariance cannot be refuted for 20% of the analyzed taxa, though. Although vicariance across Wallace's Line was only supported for one arthropod taxon, divergence time estimates were consistent with a "tectonic dispersal" vicariance hypothesis from the East in three (invertebrate and vertebrate) taxa. Speciation on Sulawesi did not occur before the Miocene, which is consistent with geological evidence for more extensive land on the island from that time. The Pliocene onset of periodic sea-level changes may have played a role in increasing the potential for dispersal to Sulawesi. A more extensive taxon sampling in Wallacea will be crucial for refining our understanding of the region's biogeography and for testing hypotheses on the origin of taxa on its most important island.

http://searg.rhul.ac.uk/pubs/stelbrink_etal_2012%20Sulawesi%20biogeography.pdf

Christian Albrecht

Papers

Ancient Lake Ohrid: biodiversity and evolution

As Time Goes by: A Simple Fool's Guide to Molecular Clock Approaches in Invertebrates*

Is deep-water gastropod decline in the ancient lakes Malawi and Tanganyika heralding ecosystem change ?

Phylogenetic relationships and evolution of pulmonate gastropods (Mollusca): new insights from increased taxon sampling.

The biogeography of Sulawesi revisited: is there evidence for a vicariant origin of taxa on Wallace's "anomalous island"?