The 21 chapters of this book are based on the theme of a Special Conference of the Systematics Association and the Linnean Society of London, held at Trinity College Dublin (TCD), Ireland, in September 2008. During the three-day Climate Change and Systematics conference, there were stimulating presentations, posters and discussions covering a broad range of ecological and systematic research relating to climate change; these influenced the shape and content of this volume. Papers were contributed by a number of conference delegates and by others subsequently invited to broaden the book's scope or address particular theoretical issues.

Consideration of the book's theme began when Richard Bateman, the then President of the Systematics Association, invited John Parnell and the School of Natural Sciences, TCD, to host a conference on the topic and to base a Systematics Association volume around its conclusions. The ideas were refined in discussions with Alan Warren, the then Systematics Association Special Volumes series editor. We are grateful to both for their input and encouragement. Two anonymous book proposal reviewers provided valuable content guidance and many anonymous reviewers also helped to improve the chapter contributions. We are particularly grateful for the manuscript preparation input of Sandra Velthuis of Whitebarn Consulting, who has worked long and hard to proofread chapters and standardise their format, to Hugh Brazier, the excellent copy editor, and to the production team at Cambridge University Press, who have been highly supportive and professional.

Abstract

Climatic change is expected to result in changes in species' distributions. However, current networks of protected areas, designed to conserve biodiversity, have been designated and designed on the basis of a paradigm of long-term stability of species' geographical distributions. As a result, these networks may not be effective in conserving biodiversity in a world with rapidly changing climatic conditions. We investigate this using as a model system the 1679 bird species breeding in sub-Saharan Africa and the network of 803 Important Bird Areas (IBAs) designated in the region by Bird Life International. Using climatic envelope models fitted to species' present distributions and the current climate, species' present and potential future occurrences in IBAs were simulated. The results show that the current network has the potential to maintain most species throughout the present century. However, they also indicate that this outcome depends upon substantial potential species turnover in many IBAs. This is only likely if the connectivity of the current network is enhanced substantially in key areas, and will also depend upon sympathetic management of the wider landscape, so as to enhance its permeability, and appropriate management of individual sites, taking into account their role in the overall network.

Introduction

It is now generally accepted that anthropogenic activities have resulted in global climatic changes over the past century (Trenberth et al.,2007); they may even have done so over several millennia (Ruddiman, 2003).

Abstract

Climatic information from distribution data of a species can be used to compute its climate envelope. Climate envelope models (CEMs) are employed to predict potential geographic ranges of species as a function of climate by comparing the climate envelope with climatic conditions at locations of unknown occurrence. CEMs find their way into applied sciences such as conservation management and risk assessment, but they also perform well in systematics and evolutionary research, often supplementary to other methods. Although the application of CEM approaches is developing rapidly, there is a considerable lack of theoretical background. We summarise theoretical assumptions behind CEMs, describe how they work and discuss possible pitfalls when interpreting results. In addition, we provide examples from our ongoing research on the Afrotropical reed frogs, genus Hyperolius (Hyperoliidae). We delimit the potential distribution of a recently recognised taxon within the Hyperolius cinnamomeoventris species complex and propose possible speciation scenarios for H. mitchelli and H. puncticulatus.

Introduction

Climate and the geographic distribution of species

It is known that climate elements and factors have an important influence on the distribution of plant and animal species; likewise, the ecological niche concept has been well discussed (Grinnell, 1917; James et al., 1984). In recent years, there has been a remarkable increase in availability of information on climatic parameters in geographic space, including remote regions. There has also been improved recording of species distribution data.

Abstract

Climate on earth has always been changing. Despite decades of investigation, our limited knowledge of the ecological and evolutionary effects of climate changes often translates into uncertain predictions about the impact of future climates on biodiversity. Integrative biogeographical approaches using palaeobotanical, phylogenetic and niche-based species distribution models, when permitted by data availability, may provide valuable insights to address these key questions. Here we combine palaeobotanical and phylogeographical information with hindcast modelling of species distribution changes to reconstruct past range dynamics and differentiation in the bay laurel (Laurus spp., Lauraceae), an emblematic relict tree from the subtropical laurel forests that thrived in Tethyan realms during most of the Tertiary period. We provide plausible examples of climate-driven migration, extinction and persistence of populations and taxa, and discuss the factors that influence niche conservatism or adaptation to changing environments. Finally, we discuss the likely impacts of the predicted climate change on laurophyllous taxa in the Mediterranean and Macaronesia.

Introduction

The reconstruction of the evolutionary history and distribution of plants has been based primarily on the information supplied by two relatively independent research fields: palaeobotany and phylogenetics. More recently, it has also relied on statistical modelling approaches to hindcast species distributions on geological timescales. Palaeobotany has long relied on the description of fossils, the resolution power of microscopes and fossil sampling in cores. Isotope dating, and other approaches for absolute timing of events, then led to a methodological revolution in this field (Stewart and Rothwell, 1993).

Abstract

We provide an overview of trends and uncertainties emerging from the growing field of climate change and biodiversity research using lichens as a study group. Problems in understanding the implications of global change for lichens are relevant to other groups comprising subdominant species such as algae, mosses and liverworts. Ecological study of lichens represents a diverse range of the ascomycete fungi, which have adopted a strategy in symbiosis with an inhabitant autotrophic partner. In general lichens may be considered ‘stress tolerators’, although contrasting lichens encompass a range of life histories with respect to reproduction, dispersal and habitat specialisation. Lichens typically occupy microhabitats nested within a larger-scale habitat mosaic and are relatively little studied compared to vascular plants and animals. We examine two main themes: (1) the direct effect of climate warming on lichens with respect to arctic–alpine ecosystems; and (2) the indirect effect of climate change on lichens resulting from interaction with other environmental factors. Within this framework we discuss the current limits to bioclimatic modelling, the role of molecular ecology in climate change studies, species interactions, and opportunities for conservation in the face of climate change uncertainty. We draw on research from across geographic regions, with several focused examples referring to lichens in Britain and Ireland, which have the advantage of being among the best-explored lichen floras in the world.

Abstract

East African rainforests are characterised by a high percentage of endemic species. The occurrence of Annonaceae in the area conforms to this pattern. We review the historical biogeography of species of this family endemic to East Africa, in the light of episodes of climate change during the Tertiary. Based on herbarium specimen data, and using a phyloclimatic modelling approach, we identify the environmental variables that are associated with the origin of East African endemics of the genus Monodora. We discuss the possible responses of Monodora to future trends, based on inferences from past evolutionary changes linked to climatic transitions.

Introduction

Ecological changes due to the process of global warming and climate change are increasingly documented (Hannah et al., 2005; Lovett et al., 2005a; Lewis, 2006). Species distributions have shifted, and changes in ethology and phenology have caused the disruption of synchrony in plant–insect and predator–prey interactions (Parmesan, 2006). One of the tools applied to study the effect of climate change on organisms is species distribution modelling (Heikkinen et al., 2006; Beaumont et al., 2007). These models, also named bioclimatic envelopes or bioclimatic niches (see Kearney, 2006, for a discussion of species distribution modelling and terms involved), reflect the potential distribution of a species that is predicted on the basis of the relationships between species absence/presence, or presence-only, data, and environmental parameters of areas in which these species occur.

Abstract

The distribution of potential hybrid zones depends largely on climate, habitat quality and historical biogeographic factors including dispersal and local extinctions. Global climate change can produce more favourable conditions for certain species to survive in areas that were previously unsuitable for their growth and/or their reproduction, and it may therefore change the potential for their hybridisation with closely related taxa. This chapter discusses general issues of plant hybridisation and invasiveness in the context of global climate change and presents a case study of hybrid ash trees (Fraxinus excelsior × F. angustifolia) that are mostly geographically separated in their natural range by climate but can have large hybrid zones. In general, both species are temporally separated by flowering times, which occur in early winter for F. angustifolia and in early spring for F. excelsior. In Ireland, introduced alien ash (F. angustifolia, F. excelsior × F. angustifolia hybrids, and non-native F. excelsior) can be found growing in sympatry with native F. excelsior populations. It is not known whether alien ash will hybridise with native populations or how climate change, principally in temperature and precipitation, will influence their hybridisation and invasiveness potential. We firstly examine the climate presently associated with known hybrid zones for ash in continental Europe and in Ireland. We then evaluate if a double CO2 global warming scenario (2 × CO2, CCM3 model) would provide improved climatic conditions for hybrids in Ireland and elsewhere.

Abstract

Accurate species delimitation is a foundational assumption of biological research. It is especially relevant to conservation, because species names are the currency for conservation policy. Cryptic species are species that are deeply genetically divergent from other such lineages, but that have escaped detection and description because they lack obvious morphological discontinuities. They are not necessarily closely related. Genetic data have revealed surprising amounts of cryptic diversity, which has provoked numerous criticisms concerning their taxonomic recognition and relevance to conservation. I critically examine these and other concerns in the context of a hypothetico-deductive framework (HDF) for species delimitation and conclude that they are unfounded. I explore links between taxonomy and systematics with respect to cryptic species recognition, claims about the relative usefulness of morphological versus genetic data for species delimitation, and the kinds of inferential errors that attach to the process of inferring species boundaries. The balance of the chapter shows that the description of cryptic diversity is an important enterprise and considers its implications for conservation biology, especially in the context of global warming.

Introduction

Biodiversity conservation is a multidisciplinary enterprise that seeks to preserve species diversity in the form of ecologically and evolutionarily viable populations.

Abstract

Terrestrial green microalgae are among the most widespread and evolutionarily diverse organisms inhabiting terrestrial environments. In the last 30 years, ultrastructural and molecular data have led to important insights into the evolution of these organisms. It has become clear that terrestrial green algae are a highly polyphyletic group originating from the colonisation of terrestrial environments by many separate lineages of aquatic algae, both freshwater and marine. Such diversity implies great differences in physiological and biochemical attributes, with the consequence that different taxa are expected to exhibit different responses to climatic changes. Elevated carbon dioxide (CO2), variations in rainfall and humidity and increased photosynthetically active radiation (PAR) and ultraviolet (UV) radiation are the aspects of global change that will most likely affect terrestrial green algae. The published information on impacts of global change is largely based on short-term studies, which have examined the immediate response of algae to experimental manipulation of climatic parameters. However, recent experimental long-term studies have shown that green microalgae evolve in response to climatic change, and the physiological responses of algal strains in present-day conditions might not reflect the responses of the same strains in future climate scenarios.

Introduction

As generally defined, the term algae includes all photosynthetic eukaryotes with the exception of land plants (Brodie and Zuccarello, 2007; Delwiche, 2007). Members of this highly diverse, non-monophyletic set of organisms occur in any habitat in which sufficient photon irradiance for photosynthesis is available, and they contribute to global primary production to an extent which may reach 50% (Beardall and Raven, 2004).

Abstract

Cyperaceae (sedges) are a monocotyledenous angiosperm plant family with over 5300 species. Despite their global importance, few, if any, climate change studies have been carried out on, or with, Cyperaceae. However, they may be a model family on which to base such work. They are of economic, ethnobotanical, conservation and environmental importance, and a wide range of resources for Cyperaceae is available. Examples are given of where Cyperaceae may win or lose in the climate change stakes. Taxa with C4 photosynthetic pathways, such as Cyperus rotundus (‘the world's worst weed’), C. longus and members of Cyperus sect. Arenarii, are potential winners that could considerably extend their distributions. Niche modelling results are presented showing the predicted areas of climatic suitability for C. rotundus (globally) and C. longus (British Isles) in 2050. Furthermore, historical distribution data are presented that show the northward range expansion of C. longus in Britain during the last 100 years. The chapter highlights the threat of climate change to endemic taxa with restricted distributions, such as Carex spp., Isolepis spp., Khaosokia caricoides and Mapania spp. These appear particularly vulnerable, although, as yet, there is no direct evidence of climate change threatening or eliminating taxa.

Introduction

Cyperaceae (sedges) are a monocotyledenous angiosperm plant family with 106 genera and 5387 species (Govaerts et al., 2007). They are placed in the order Poales and have a superficial similarity to Poaceae (grasses). Both families have much reduced flowers and are primarily wind-pollinated.

Abstract

Cyclamen is a genus of popular garden plant, protected by Convention on International Trade in Endangered Species (CITES) legislation. Many of its species are morphologically and phenologically adapted to the seasonal climate of the Mediterranean region. Most species occur in geographic isolation and will readily hybridise with their sister species when brought together. We investigate the biogeography of Cyclamen and assess the impact of palaeogeography and palaeoclimate change on the distribution of the genus. We use techniques of phyloclimatic modelling (combining ecological niche modelling and phylogenetic character optimisation) to investigate the heritability of climatic preference and to reconstruct ancestral niches. Conventional and phyloclimatic approaches to biogeography are compared to provide an insight into the historic distribution of Cyclamen species and the potential impact of climate change on their future distribution. The predicted climate changes over the next century could see a northward shift of many species' climatic niches to places outside their current ranges. However, such distribution changes are unlikely to occur through natural ant-based dispersal, so conservation measures are likely to be required.

Introduction

Cyclamen: present-day status and distribution

Cyclamen L. is a genus of c. 20 species in the family Myrsinaceae. Its species are perennial herbs, having distinctive flowers with reflexed petals, that are often scented, and winter blooming. These characteristics make Cyclamen a popular garden plant. Its popularity has prompted many studies on the group, including cytology (Bennett and Grimshaw, 1991; Anderberg, 1994), hybridisation (Gielly et al., 2001; Grey-Wilson, 2003) and phenology (Debussche et al., 2004).

Abstract

Increased political interest in addressing environmental issues, notably climate change, conservation and landscape restoration, has the potential to strengthen the focus, integration and profile of systematic biology. In particular, it could rescue descriptive taxonomy from its current state of near-extirpation in the developed world. However, exploiting this opportunity will require greater consensus than the systematics community has previously achieved, together with the determination to resist exaggerating the value of existing systematic data and of technological advances such as DNA barcoding and web-based identification. Descriptive taxonomy erects hypotheses of species existence that must be tested using other categories of data if systematics is to become a genuinely predictive enterprise. Prediction followed by recommendations for adaptation and/or mitigation, each essential to address the consequences of climate change, are possible only with good knowledge of the species and ecosystems under scrutiny. Taxonomic data alone are of little value, but, equally, non-taxonomic data are rarely of value in the absence of a taxonomic framework. Instead of seeking shortcuts to, or even substitutes for, taxonomy in the hope of accelerating the rate of superficial species description (and redescription), the climate change challenge is best addressed by obligatorily increasing the rigour required in taxonomic descriptions. This especially requires: (1) escaping from traditional typology by prescribing minimum levels of both morphological and molecular data via obligatory online registration of species; (2) requiring taxonomists to state the species concept(s) employed in each study; (3) improving feedback to taxonomy from identifications performed by non-systematists; and (4) prioritising groups for taxonomic study according to the importance of the questions that the study group can address.

Abstract

Plant taxonomy must re-evaluate its outputs in order to be part of an effective response to climate change. Traditional taxonomic works, such as floras and monographs, are not appropriate tools for plant conservation and monitoring programmes. Such outputs need to be more widely supplemented with practical, field-based publications (field guides), which are more suited to providing rapid species identifications in the field. This chapter argues that to be as effective and as inclusive as possible, plant field guides need to be based on images rather than text. Using recent case studies from the Arabian Peninsula, we present a series of practical methods for documenting plant species using digital photography and assess the advantages and disadvantages of digital image-based identification.

Introduction: current Arabian climate

The latest climate projections for the Arabian region predict significant change by the end of the twenty-first century. According to Dawson (2007), under a low-emissions scenario (B2a), across much of the region, the mean winter temperature is predicted to have increased by 3 °C and the mean summer temperature by up to 4 °C in 2070–99. In the same period, under a high-emissions scenario (A1f), predictions suggest that the mean winter temperature will have increased by 5 °C across much of the region. The mean summer temperature is likely to increase by up to 6 °C in the south and 7 °C in the north of Arabia.