Monday, August 25, 2008

Interview with Shai Meiri, Research Fellow, NERC Centre for Population Biology, Imperial College London

Shai Meiri is interested in the evolution of body size and its implications, in biogeographical correlates of morphology and in the morphological signatures of speciation and community composition.

Relevance of biogeography to your work
Antje Ahrends. Do you think that biogeography has important implications for conservation in practice?
Shai Meiri. I think it sometime have important implication for conservation, but very often does not, and every case have to be examined in detail.
AA. Do you read conservation journals, or otherwise receive information on new developments in conservation practice/policy?
SM. I admit I seldom do.
AA. Do you think that biogeographers have a responsibility to contribute to conservation in practice, or should research be entirely free of political agendas? Does your research help conservation in practice? Which stakeholder group is benefiting from your research, and how do you communicate your findings?
SM. I think all humanity has a responsibility to conservation, and of course all organismal biologists cannot do wrong if they contribute to conservation science, but responsibility? I’m not sure. If one is doing e.g., basic science than one has no responsibility, unless you are funded by a conservation body. Research should always always always be free of political agenda. Politics is not science. I communicate my findings by publishing them in the scientific media, representing them in conferences, sometime presenting them to the media, and sometime by teaching graduate and undergraduate students.

General practicality of incorporating new biogeographic findings in conservation
AA. It is still uncertain to which degree predictive species distribution models are applicable at a local scale. Also, there are necessarily a lot of uncertainties associated with the predictions at all scales. Do you think that the results of these models should nevertheless be communicated to conservation practitioners and potentially influence management decisions? Is there a risk that the validity of these models is over-estimated?
SM. I think there is a very substantial risk that the models are wrong and overestimated. This is not to say they should not be developed, but the developers and “consumers” should be aware of the potential for error, which I feel can often be substantial.
AA. Implementing conservation strategies is partly reliant on public and decision makers' support. The communication of uncertainty or conflicting messages can be difficult, for example with respect to the merits of existing prioritisation schemes such as hotspots and Global 200. Do you feel that this aspect of conservation hampers the integration of newer research findings? Do you generally perceive a gap between biogeography science and conservation policy?
SM. I confess not to have understood the question fully. I think that if scientists are uncertain this uncertainty must be presented, and never covered-up or ignored.
AA. Conservation planning needs long-term strategies. Do you perceive a gap between the comparatively rapid turn-over of existing paradigms in science and their acceptance in the conservation world?
SM. I don’t know, because I don’t know what “the conservation world” is, or what is meant by paradigms here. The term paradigm is often miss-used. It should refer to the major unifying theories of our science, and this has been Darwinian biology for the last 150 years. What turnover?

Communication between biogeographers and conservation practitioners
AA. Do you think that biogeographers communicate the applicability of their research findings to conservationists adequately? And vice versa, do conservationists adequately communicate their information needs to biogeographers?
SM. I am not sure what “adequately” means in this context. I think conservationists do not usually communicate their information needs to biogeographers – and maybe because they don’t perceive biogeographers as having the necessary answers to the questions they ask. I am not sure they are wrong. I think some biogeographers who say their research has implications for conservation may be wide off the mark.
AA. Is an intensified exchange between conservationists and biogeographers necessary, and if so, where do you see potential platforms for this?
SM. I don’t know whether it is really intensified, or necessary. Potential platform? a conference and a journal (I propose the original name “conservation biogeography”) may be good.

Friday, August 22, 2008

Geoplatform, a new web portal providing unified access to free environmental cartography

The European Distributed Institute of Taxonomy (EDIT) is a collective project of 27 leading European, North American and Russian institutions financed by the European Commission since 2006. Among its objectives, EDIT aims to create shared resources within European taxonomic research institutions. Given the need for an accessing and processing geographical data, one of the core projects of EDIT is the development of Geoplatform, a portal of geographical resources for biologists. These resources include promoting the accessibility to the environmental digital data through a web page where environmental cartography from diverse sources gathered in a unified way is freely available. This web page is now online at http://edit.csic.es/GISdownloads.html, and includes an important amount of geographical information for a variety of thematic areas, from climate and topography to worldwide regular grids, stored in IDRISI® and ESRI® shapefile formats.
EDIT’s Work Package 5 (Internet Platform for Cybertaxonomy) invites the community of taxonomists, biogeographers, ecologists and conservation biologists to access and use this information freely. They also will be grateful to receive any supplementary information on data sources and/or freely available digital cartography that could be incorporated to Geoplatform’s GIS database, thus contributing to the original purpose of the corresponding open information sources: their universal availability.

Thursday, August 21, 2008

Wind highways on the ocean drive the route and dynamics of migrations

In 2004, a group of Spanish researchers demonstrated, in an article highlighted as cover by Science, that invisible wind highways can explain why areas separated by thousands of kilometers can share a large number of species.
Now, two members of the original team, Ángel Felicísimo (Universidad de Extremadura) and Jesús Muñoz (Real Jardín Botánico, CSIC) have joined a birds' specialist, Jacob González-Solís (Universitat of Barcelona) to demonstrate that those wind highways follow a very precise route and, moreover, they are only accessible during very precise periods of time.
In the present paper, published in the open-access journal PLoS ONE, they used birds equipped with geolocators to identify the routes they follow in their migratory flyways, something in which González-Solís has been working for years. Cory's shearwaters (Calonectris diomedea), which breed in the Canary Islands and winter offshore South Africa and Namibia were the ideal candidates for two reasons. Firstly, because far from following the great circle route to cover the approximately 8000 km that separate the Canary Islands of South Africa, they follow a detour of 3000 km to almost reaching Brazil before turning east to Africa. How can it be profitable for a 800 g bird to make such immense detour? Secondly, they fly using a very peculiar technique: surfing the air that waves push in front of them. Given that ocean waves are produced by wind, nothing better than using the data generated by the satellite that measures wind's characteristics –the QuikSCAT, already used by Felicísimo and Muñoz in their previous research– to assess if shearwaters used the wind highways between Canary Islands and southern Africa.
Analyzing daily oceanic winds measured by QuikSCAT and comparing them with the birds' location, the authors found that the previously unexplained flyway followed by the Cory's shearwaters is exactly the most efficient during the migration time. Shorter pathways would represent higher energetic costs by flying against prevailing winds.

Minimum cost corridors according to SeaWinds in the migration period of Cory's shearwaters (left) and density of their trajectories (right).
Source: PLos ONE

Another result –this unexpected– is that the trip cannot be done in any time of the year, as there is an invisible temporal “gate” north and close to the Equator that is closed for months in the form of calms or contrary winds. Only when favorable winds start do Cory's shearwaters initiate their great joint southward journey.
In this research, the authors used new techniques specifically developed for these spatio-temporal analyses, which allow to mathematically demonstrate for the first time how winds constrain the main migratory flyways both spatially and temporally. These results open new avenues of research in fields like pathogens spread or when prophylactic treatments are more effective, species dispersal and migration, how species evolve after colonizing new areas, and even which species can be the ancestor of others.
Source paper: Felicísimo, Á.M., Muñoz, J., & González-Solis, J. (2008) Ocean surface winds drive dynamics of transoceanic aerial movements. PLoS ONE, 3, e2928.

A new web portal to access the database on Azorean biodiversity

The Azorean Biodiversity Portal (http://www.azoresbioportal.angra.uac.pt) is available. For the first time it is possible to have access to the detailed distribution of all the Azorean terrestrial flora and fauna mapped in a 500x500 m grid based on literature records. For some species some images are also provided. For threatened species only their presence/absence in the islands is available.
This portal was developed under the INTERREG III B Projects "Atlântico" (2003-2005) and "BIONATURA" (2007-2008), involving several Azorean and Canarian partners. This long-term project was developed by four different research groups of the University of the Azores, coordinated by Paulo A. V. Borges, including researchers from the Azorean Biodiversity GroupCITA-A and the Department of BiologyCIBIO.
For more information or detailed maps of the spatial distribution of species richness please contact the coordinator of the project, Paulo A. V. Borges, at pborges(at)uac.pt.

Wednesday, August 20, 2008

Interview with Wendy Foden, Programme Officer – Climate Change, IUCN

Wendy Foden’s passion for conservation stems from her love of wild and remote places. Following the completion of her studies in Biology and Conservation at the universities of the Witwatersrand and Cape Town in South Africa, she travelled and expeditioned through Tanzania, India and China. Wendy then joined the Global Change and Biodiversity Research Group at the South African Biodiversity Institute (SANBI). Here she focused on the impacts of warming on the Southern Africa’s arid ecosystems, and uncovered evidence of a climate driven range shift by the giant tree succulent, Aloe dichotoma. Remaining at SANBI, Wendy then joined the Threatened Species Programme as Programme Manager. In this role, she founded of new projects focusing on the monitoring and conservation assessment of South Africa’s plants, reptiles, arachnids and butterflies. She also played an important role in developing and implementing South Africa’s Biodiversity Act, particularly in sections relating to threatened species.
Wendy now leads the IUCN’s “Species Vulnerability to Climate Change” project. By identifying and collecting data on life history and ecological traits associated with particular vulnerability to climate change, she aims to identify those species that face the greatest risk of climate change driven extinction. The results will be used to compliment the current IUCN Red Data List and to help prioritise conservation efforts.

Relevance of biogeography to your work
Antje Ahrends. Is biogeography – “the study of the geography of life” – a relevant discipline to your work for the IUCN? Do you think it is relevant to practical conservation planning in general?
Wendy Foden. Yes, definitely. A species’ geographical distribution range is one of the fundamental pieces of information needed to assess their threat (Red List) status. In terms of our climate change focus, accurately determining a species’ range is particularly important for defining the climatic characteristics it requires, and projecting the position of these under climate change scenarios for the future (i.e. bioclimatic modelling). We rely heavily on biogeographic research into species distributions and distribution and climate change models.
AA. Do you read biogeographic journals, or otherwise receive information on new findings in the field of biogeography? What are your main sources for this?
WF. While I don’t specifically seek out biogeographic journals, research on climate change impacts on species frequently falls into their domain, particularly on issues such as past and current range shifts. So yes, I do frequently read articles from them.
AA. Does the IUCN collaborate with biogeographic research institutions?
WF. The IUCN receives information on species from a huge network of scientists from around the world, particularly through the Species Survival Commission’s specialist groups. This includes individuals from biogeographic research organisations, as well as those researching biogeographic issues from within their own specific disciplines and institutions.

The general practicality of incorporating new biogeographic findings in conservation work
AA. Do you think that idealistic prioritisation schemes have much relevance on the ground (other than attracting funding)? I.e. is it useful to have these benchmarks although they are (1) necessarily based on incomplete data and (2) generally do not take into account political or socioeconomic constraints?
WF. I believe that, as planners and biologists, we need to be braver. Our role is to provide the most accurate projections possible and highlight what needs to be done to achieve a given objective. If, for example, we’re planning and mapping the areas needed to protect a group of endemic species, then irrespective of the politics or other constraints, these are our very best estimates of the species’ needs for survival. It’s not for us to downplay them. Even inconvenient or “idealistic” results should be presented so the basics are clear – and the inevitable political manoeuvring can proceed thereafter.
AA. The nature of scientific research is to continuously challenge existing paradigms, and as a consequence there frequently is a lot of disagreement and a rapid-turnover of paradigms. For instance, a predictive model for species distributions that was deemed the state of the art a few years ago might already be regarded as flawed today! Does this scientific rationale make it difficult to include biogeographic findings in conservation practice given that conservation generally needs longer term strategies and commitments?
WF. When our job is to predict the future, particularly where there’s no precedent for the situations we’re in and there are millions of variables to consider, I think we’ve got to be ever ready to humbly and frequently correct ourselves. Nonetheless, we need to act now (well, we needed to act quite a while ago on climate change) and we need to use the very best information we can find.

Communication between biogeographers and conservation practitioners AA. Do you think that biogeographers communicate the applicability of their research findings to conservationists adequately? And vice versa, do conservationists adequately communicate their information needs to biogeographers?
WF. An area in which better communication could be mutually very beneficial to conservation and biogeography is in the digitisation, ‘cleaning’ and sharing of species distribution data, as well as sharing new collection localities. In addition to publishing such findings, this is facilitated via online open access resources such as the Global Biodiversity Information Facility (GBIF); via taxon-specific databases such as FishBase, ePIC (Kew Botanical collections database), the Global Amphibian Assessment database; or via appropriate regional databases such as the National Biological Information Infrastructure (USA).
Given the extreme conservation crisis we currently face, I feel that each researcher who withholds species data that could be potentially useful for conservation should ask themselves some serious questions about their ethics. We need to pool our resources if we’re going to have any chance of stemming the looming extinction crisis.

AA. Are there any further thoughts you would like to share:
WF. The IUCN focuses particularly on threatened species which tend to have small distributions and few distribution records either because they’re naturally rare, their ranges have declined greatly or because they are very poorly known. Distribution and climate change models tend to perform poorly for such species, leaving us with least confidence in our projections for the species about which we’re most concerned. This is an area in which we hope the biogeography community will be able to help us.

Tuesday, August 19, 2008

Do microorganisms have biogeography?

Diego Fontaneto
Imperial College London, Division of Biology, Silwood Park
e-mail: d.fontaneto(at)imperial.ac.uk
Joaquín Hortal
NERC Centre for Population Biology, Imperial College London, Silwood Park
e-mail: j.hortal(at)imperial.ac.uk


Diego Fontaneto (right) and Joaquín Hortal (left)

Zoologists and botanists look to exotic places in order to find interesting new species and higher taxa. Over the last few centuries, scientific expeditions in remote places have indeed discovered new species and even higher taxa of limited distribution. Such discoveries still occur in recent years. The new insect order Mantophasmatodea in Namibia and Tanzania (Klass et al., 2002) was only known from fossil specimens in amber (Arillo et al., 1997). Even recently the new rodent species Laonastes aenigmamus was found in Laos; a new family was proposed to classify this species (Laonastidae; Jenkins et al., 2004), although it was later included in the Diatomydae (Dawson et al., 2006), a family that was also known only from fossil remnants (Mein & Ginsburg, 1997). The fact that in both cases these new higher taxa were already known from fossils does not diminish the need to explore remote areas to find new living branches in the macroscopic part of the tree of life.

Hypsibius dujardini (phylum Tardigrada).
Picture by Willow Gabriel and Bob Goldstein / Public Domain. Source: http://tardigrades.bio.unc.edu/.

In contrast, collecting samples in remote areas, scientists working on the less-known microscopic organisms (smaller than 2mm) invariably found species and higher taxa that could be ascribed to taxa already known from Europe (Fenchel & Finlay, 2003). Once completely new higher taxa are discovered, they are quickly found to be widely distributed. The recently described microscopic animal phyla, Loricifera from marine sediments off the coast of France (Kristensen, 1983), Cycliophora on the mouthparts of lobsters in Denmark (Funch & Kristensen, 1995) and Micrognathozoa in cold springs in Antarctica (Kristensen & Funch, 2000), have all been suddenly found in regions very distant from the original type locality, but in similar habitats, which were in fact previously unexplored (Todaro & Kristensen, 1998; De Smet, 2002; Nedved, 2004).
The difference between macro- and microorganisms can be illustrated with the example of what is actually found when a small region is surveyed. Forty-eight Tardigrada species were found in an extensive survey of rock mosses and leaf litter of a mountain range at the Iberian Peninsula (using tiny 3x3 cm cores) (Guil, 2008). From these, only six species (12.5%) are only known from a single continent (Europe). This count includes two new species that, obviously, are only known from Central Iberian Peninsula. At least for now. Taxonomical and biogeographical knowledge on the phylum Tardigrada is far from being complete, and is seriously unbalanced through the regions of the world (Guil & Cabrero-Sañudo, 2007). However, this example illustrates that the communities of microscopic organisms host high proportions of widespread and cosmopolitan species, to the extent that 20% of all known bdelloid rotifers have been found in a small Italian valley (Fontaneto et al., 2006), and 50 % of all named species of heterotrophic flagellates have been recorded in a small Danish Bay (Fenchel and Finlay, 2004).
It is commonly thought that most species have restricted distributions (see, e.g., Gaston, 2003). However, very few microbiologists will endorse such a statement (see, e.g., Fenchel & Finlay, 2003, 2004). Why do microscopic and macroscopic organisms differ so widely in their patterns of distribution? The Baas-Becking (1934)’s hypothesis, also known as the “Everything is Everywhere” (EisE) hypothesis, encapsulates the classical view that microscopic organisms are globally distributed due to their high potential for dispersal (Kellogg & Griffin, 2006). Small size and an ability to enter dormancy, and therefore to produce dormant propagules (Cáceres, 1997; Bohonak & Jenkins, 2003; Fenchel & Finlay, 2004), might explain why prokaryotes and some microscopic eukaryotes, such as protists and small invertebrates, have acquired global distributions.
The assumption that organisms smaller than 2mm have cosmopolitan distribution often holds true when species are defined using traditional taxonomy. However, the EisE hypothesis has been challenged recently. Recent molecular evidence reveals distance-decays in the similarity of microorganisms belonging to the same traditional species in a variety of microscopic organisms, including prokaryotes (Cho & Tiedje, 2000; Whitaker et al., 2003), protists (Darling et al., 2004; Foissner, 2006; Telford et al., 2006), and fungi (Taylor et al., 2006). Other studies have found cases of restricted distributions solely by re-evaluating morphological evidence within species previously assumed to have cosmopolitan distributions (Smith & Wilkinson, 2007). All this evidence points out that there might be a high degree of cryptic diversity in the microbial world, and that there are more restrictions to the dispersal of microscopic organisms than previously thought.

Chaetonotus sp. (phylum Gastrotricha).
Picture by M.A.Todaro. Source: http://www.gastrotricha.unimore.it/

The current debate on the EisE hypothesis divides scientists in two major groups (Whitfield, 2005). On one side, scientists following the EisE hypothesis in its original form assume that species differences in samples from different areas occur because of environmental differences, and not because of restricted dispersal. Thus, they consider that “everything is everywhere, but the environment selects” is the rule for microorganisms (e.g. de Wit & Bouvier, 2006; Fenchel & Finlay, 2006). On the opposite position, other scientists propose that classical morphological taxonomy of microscopic organisms is not able to resolve their actual diversity, and therefore that cosmopolitan ranges result from misidentification and lumping of spatially isolated lineages (e.g. Coleman, 2002; Foissner, 2006; Taylor et al., 2006).
The straightforward way of solving this debate would be to determine if environmental selection by microorganisms (i.e., environmental filtering) does actually cause reproductive isolation and/or limits gene flux. It has been argued that it would be difficult to falsify the EisE+environmental selection hypothesis, because there could be unmeasured aspects of the environment that differ consistently among regions (Foissner, 2006). However, if we assume a dense sample of equivalent habitats across sampling regions, the hypothesis makes clear predictions about genotype distributions. If EisE is the rule, the degree of genetic relatedness between two individuals should be independent of the geographic distance between them, except that individuals within a habitat patch might be more closely related to one another than those in different habitat patches. Conversely, if EisE does not hold true, spatially explicit models should work in the same way as they do for macroorganisms, and genetic diversity should be related to geographic distances by a classical distance-decay relationship.
Microscopic animals can be used as a model to test the EisE hypothesis, to assess (i) if there are environmental effects on the distribution and composition of microscopic assemblages, and (ii) if there are environmentally- or distance-driven genetic differences among the individuals of the same evolutionary entity (i.e., the same taxon). On the one hand, environmental effects on microscopic communities across space have been tested in very few model organisms; up to now empirical studies are available only for local samples for bdelloid rotifers (Fontaneto et al., 2006), tardigrades (Guil et al., conditionally accepted), and mites (Valdecasas et al., 2006). These studies show contrasting results. While habitat filtering seems to be important at the landscape scale for bdelloid rotifers and tardigrades, water mites show only weak associations with habitat. On the other hand, explicit genetic tests on the strength of spatial patterns (such as distance-decay relationships) have been performed only for two genera of bdelloid rotifers (Fontaneto et al., 2008), and for one species complex of monogonont rotifer(Brachionus manjavacas; Gómez et al., 2007; Mills et al., 2007). These studies confirmed that even microscopic animals have biogeographies and show persistent genetic signature of colonisation.
Undoubtedly, more studies on the diversity patterns of microorganisms, dispersal abilities and their phylogeographic structure are yet needed (Jenkins et al., 2007). Supporting or denying the EisE hypothesis needs much more work at different spatial scales, and also a comprehensive coverage of other groups of microscopic organisms, including bacteria, protists, microscopic algae, animals and fungi. However, the potential of microorganisms for biogeography and macroecology might go far beyond than merely solving the question of whether they are truly widespread, or not. As said before, we know that at least a few groups show responses to microenvironmental differences, which sometimes can be very narrow. Little is known about the exact nature of these responses, but identifying the particular responses of individual species provides a way of tracking environmental changes by comparing the composition of microbial assemblages. This, together with ubiquity of some microscropic groups, makes them potential candidates to be used as universal indicators, allowing comparisons between very distant places distributed worldwide.

The monogonont rotifer Brachionus manjavacas.
Picture by Diego Fontaneto and Giulio Melone

Apart from that, microhabitats in nature provide means of testing biogeographical hypotheses, as exemplified by the analysis of the species-area relationship carried out by Bell et al. (2005). They assumed that water-filled holes at the base of large beech trees are independent islands sharing the same bacterial species pool, and measured species richness as bacterial genetic diversity, and island size as water volume in each tree-hole. The species area relationship (measured as a power law) was highly significant, and showed a slope similar to the one found in many macroscopic continental island systems. This is just an example of the silent revolution undergoing in microbial ecology (Prosser et al., 2007). Microbial model systems are already being used to re-analyze part of the current theoretical body of ecology and biogeography (Jessup et al., 2004), which until recently have been almost exclusively based on macroscopic organisms.
A better knowledge on the biology of some groups of microorganisms and the molecular techniques now available can help solving two of the major drawbacks of biogeography as a hard science: the impossibility or extreme difficulty of performing experiments, and the limited number of real world examples that can be used to evaluate the proposed hypotheses and/or models. Contingency makes the evaluation of concurrent hypotheses on the distribution of biodiversity very difficult (see, e.g., Hawkins, 2008). We believe that some microorganisms provide a mean to make true experiments in biogeography, for they allow setting up experimental designs affordable in terms of time and money. For example, being the dispersal of some of them potentially unlimited and passive at the same time, they can allow formal tests of the neutral theory (Hubbell, 2001). By adding filters to dispersal and/or designing experimental islands with particular characteristics, experiments on island biogeography can also be made. Some groups, such as bacteria, or the bdelloid rotifers, tardigrades and mites mentioned above, can provide manageable study systems and help establish the basis of a harder biogeographical science.

The bdelloid rotifer Macrotrachela quadricornifera.
Picture by Diego Fontaneto and Giulio Melone.


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The peninsula effect may yet be seen as a red herring, but more light is needed

The peninsula effect is a classic biogeographical concept which predicts that the number of species declines from a peninsula’s base to its tip. Two of three hypothesized causal mechanisms, the effects of geological history or habitat on species richness, can be controlled for by study design and/or statistical analysis. The third proposed mechanism (reduced colonization towards the peninsular tip) is attributed to peninsular geometry, and is less easily controlled. Dave Jenkins and Deb Rinne of the University of Central Florida asked two questions: (1) what is revealed by the 4-decade history of research on this concept; and (2) do microcrustaceans in Florida's isolated wetlands reveal a peninsula effect if the effects of history and habitat are controlled for?
Their literature review revealed mixed (49%) support for a peninsula effect, and found that most studies (86%) were not designed to control for alternative hypotheses or to quantitatively compare evidence regarding alternative hypotheses. Also, studies were strongly skewed to vertebrate animals (62% of studies); relatively little is known for other taxa. After controlling for history effects by study design, their own study of microcrustaceans in Florida wetlands revealed that habitat effects dominated (82.5%) the pattern, and virtually no effect of peninsular geometry existed. This result is consistent with effective dispersal of microcrustaceans through geological time.
This study is important because it shows that much illumination is still needed on the long-standing concept of a peninsula effect, and demonstrates that careful study design and statistical analyses can shed needed light. Peninsula effect studies should: broaden in taxonomic focus; control for alternative causative hypotheses (geometry, habitat, or history) in the study design; and quantitatively compare the effects of hypothesized mechanisms on peninsular diversity patterns.

Source paper: Jenkins, D.G. & Rinne, D. (2008) Red herring or low illumination? The peninsula effect revisited. Journal of Biogeography, doi: 10.1111/j.1365-2699-2008-01943.x.

Source of article: Journal of Biogeography highlighted papers

Uncovering genetic divergence and routes of gene exchange in the sand-obligate pallid kangaroo mouse, M. pallidus, from the Great Basin Desert

Kangaroo mice belong to the genus Microdipodops Merriam and are uncommon and rather bizarre-looking rodents, having enormous heads and large hind feet relative to their small (about 10 g) body size. The genus is endemic to the Great Basin of North America and includes two species: M. pallidus Merriam and M. megacephalus Merriam. The pallid kangaroo mouse, M. pallidus, is a sand-obligate desert rodent and this study examines its geographical distribution and formulates a phylogeographical hypothesis. This study also introduces a new analytical tool for testing orientation patterns in haplotype sharing for evidence of past episodes of gene flow.
The study examines mitochondrial DNA sequence data from early 100 individuals of M. pallidus sampled throughout its geographical range. The distribution of M. pallidus appears to be remarkably stable and is virtually unchanged from that determined three-quarters of a century ago. Unlike some other kinds of organism that show distributional adjustments in response to global climate change, there is no northward (or elevationally upward) distributional movement trend detected in M. pallidus.
Phylogenetic analyses show two principal clades, distributed as eastern and western units. The two clades are likely to represent morphologically cryptic species that diverged about 4 Ma. Results of this study (and a related study) now paint a picture of an endemic Great Basin taxon that diverged much earlier than thought previously and well before the creation of the extensive sandy environments during the Pleistocene and Holocene.
The directional analysis of phylogeographic patterns (DAPP analysis) used in this study is novel and may be useful in other studies. DAPP uses angular measurements of haplotype sharing between pairs of localities and circular statistical analyses to detect and quantify historical events pertaining to movement patterns and gene flow. DAPP analyses show significant, non-random angular patterns in both clades of M. pallidus. The phylogeographical patterns described here (both the eastern–western clades and the nonrandom directional patterns) may serve as a model for other sand-obligate members of the Great Basin Desert biota.

Source paper: Hafner, J. C., Upham, N. S., Reddington, E. & Torres, C. W. (2008) Phylogeography of the pallid kangaroo mouse, Microdipodops pallidus: a sand-obligate endemic of the Great Basin, western North America. Journal of Biogeography, doi: 10.1111/j.1365-2699.2008.01942.x.

Source of article: Journal of Biogeography highlighted papers

Global climate change is transforming Kakadu National Park

Kakadu National Park, Australia’s premier National Park, is being transformed by global climate change. Using advanced statistical analyses of historical sequences of aerial photography, Professor David Bowman, from the University of Tasmania, and his research team were able to show that woody plants have proliferated in the last 50 years within Kakadu’s savanna landscape and have transformed sections of treeless floodplains into tracts of scrub.
Such marked increase in woody cover is surprising given concerns about the impact of hostile fire regimes on the Park and the legacy-effects of an irruption of feral water buffalo that was finally brought under control by a sustained control programme in the 1980s. However, the analysis is consistent with a number of previous related studies undertaken by Bowman’s team. The cause of the expansion is related to a trend of increased rainfall in northern Australia and possibly the ‘fertilizer effect’ of increased atmospheric carbon dioxide, which favours growth of woody plants over that of tropical grasses.
The increase in woody vegetation has accelerated over the last 50 years because woody patch growth increases in a compound fashion. Such a non-linear pattern of woody increase has contributed to the erroneous belief that buffalo were the cause of the woody growth on the previously treeless floodplains – in fact the analysis showed that the buffalo control programme merely coincided with the dramatic expansion of woody plants.
The study is important as it shows the pervasive effects of global change on regional ecosystems. The expansion of woody plants is degrading wildlife habitat quality of Kakadu National Park’s iconic wetlands, particularly for water-birds that need treeless conditions. The upside, however, is that the park is capturing carbon in the woody growth. However, these effects may be transitory, as the IPCC’s recent climate change assessment has identified the Kakadu freshwater floodplains as being at risk of destruction due to sea level rise during this century.

Source paper: Bowman, D. M. J. S., Riley, J. E., Boggs, G. S. , Lehmann, C. E. R. & Prior, L. D. (2008) Do feral buffalo (Bubalus bubalis) explain the increase of woody cover in savannas of Kakadu National Park, Australia? Journal of Biogeography, doi: 10.1111/j.1365-2699.2008.01934.x.

Source of article: Journal of Biogeography highlighted papers

Tuesday, August 5, 2008

Registrations for the Merida meeting now open!!

Your IBS Board and specifically Ella Vazquez-Dominguez and the Local Committee at the Instituto de Ecologia, Universidad Autonoma de Mexico, Mexico D.F. invite you to plan ahead now to attend the 2009 biennial meetings of the IBS in Merida, Yucatan, Mexico from 8 to 12 January 2009.

Meeting registration and abstract submission are now available on the following website: http://www.biogeography.org/html/Meetings/index.html

Hotel reservations should be done through InterMeeting, a professional company in charge of the organization of the IBS Meeting. In order to do the reservation, please complete the Hotel Reservation Form available on the meeting webpage and send it by fax (+52 55) 5663-0035) or email.

Merida is in the midst of cultural, natural, historical, and geological riches. The beautiful colonial "White City" was founded in January 1542 on the ruins of the Mayan city of T'ho, and is only 120 km from the archeological wonders of Chichen Itza.

The center of the Chicxulub Crater, formed from an asteroid impact 65 mya and implicated in the K-T extinctions, is located 20 km outside of Merida (in the pueblo of Chicxulub).

Several biosphere reserves are within easy distance of Merida (e.g., Celestun and Ria Lagarto Biosphere Reserves). Check out these and other enchanting features of Merida on the web (e.g., http://www.visitmexico.com/wb/Visitmexico/Visi_Merida).

Climate should be ideal in January, and we're planning field trips to explore the natural and archeological wealth of the region.

We are looking forward to seeing everyone in January!

Saturday, August 2, 2008

New IBS web page

The International Biogeography Society has just launched a brand new, more attractive design for its web page, at the usual address (http://www.biogeography.org/). There you can easily access the formerly available sections, including resources, the Newsletter, links to publications and the IBS blog, or access to your membership benefits.


Also, IBS news and events are highlighted in the main page, where currently you can find a direct link to the registration process for the Mérida meeting (see above), and non-members can easyly find how to join the IBS. Do not forget to encourage other fellow biogeographers to come to the next IBS meeting and eventually join us as new members.