PAGES Magazine articles

The annual discussion meeting of the Quaternary Research Association was held in the picturesque, winter landscape of the New Forest National Park in southern England. The overall theme of the meeting was “Quaternary Science and Society” and it proved to be popular, attracting over 100 attendees. The PAGES-Focus 4 sponsored open sessions “Human-climate-ecosystem interactions: learning from the past” took up four of the 10 sessions. PAGES helped to support eight early career researchers from Australia, Romania, the USA, and the UK to attend the Focus 4 sessions. The Focus 4 presentations were split into several groups. One group focused on the response of past human societies to climate change as reconstructed linking archeological and paleoecological data. Within that group Andy Dugmore (Edinburgh, UK) showed how resilience theory could be combined with detailed and interdisciplinary studies of past communities across the North Atlantic to explain the reasons for either social collapse or long-term sustainability. Michael Grant (Wessex, UK) described how the past trajectories of woodland species in the local New Forest were providing insight into modern day management of the woodlands. One of the PAGES-supported early-career researchers, Giri Kattel (Ballarat, Australia), used paleolimnological data to assess human-climate-ecosystem linkages illustrating how sediments in maar (crater) lakes could be used as recorders of climate regime shifts and to study adaptability of past ecosystems.

A second group of papers were methodology-centric with reports on the development of isotopic and bimolecular analyses, and on approaches to translate pollen records into land use cover. Virgil Dragusin (Bucharest, Romania) explored possible human-environment interactions during the Bronze and Iron Ages in SW Romania as recorded by carbon stable isotopes in speleothems. Joseph Williams (Kansas, USA) was drawn to the discussion of novel approaches in environmental and biodiversity change, such as the ongoing development of plant biomarkers and ancient DNA analysis. Hazel Reade (Cambridge, UK) assessed the paleoclimatic interpretation from the isotopic analysis of tooth enamel with regard to the archeological record of Northeastern Libya.

Figure 1: Lower Yangtze basin 1930-2006: normalized regulating service proxy records for biodiversity, sediment regulation, soil stability, sediment quality, water quality, air quality and regulating service (RS) Index based on lake sediment analyses, showing downward trends (losses of services) towards the present. Vertical bars show major 20th-21st century political events (from left to right): Sino-Japanese War 1937-1945 (SJW); People's Republic of China founded by Mao Zedong 1949 (PRC); Great Leap Forward 1958-1961 (GLF); Cultural Revolution 1966-1976 (CR); Deng Xiaoping's economic reforms from late 1970s-early 1980s (DX); leadership of Jiang Zemin from 1989 (JZ); leadership of Hu Jintao from 2003 (HJ). After Dearing et al. (2012).

A third group linked paleoenvironmental studies to past and present socio-ecological resilience. Using multiproxy records, this group of studies revealed long-term interactions between climate, human activities and ecosystem services, the presence of thresholds and early warning signals, and reference conditions for conservation. Zhang Ke from Southampton (UK) shed light on recent attempts to use paleoenvrionmental records as proxies for ecosystem services in the lower Yangtze basin (Fig. 1). The paper by Wang Rong (Southampton, UK) examined the evidence for early warning indicators of eutrophication in lake sediments from southwestern China. And Helen Shaw (Lancaster, UK) assessed paleoecological and historical contributions to understanding sustainability, resilience, and ecosystem services within traditional pastoral management. The wide range of questions that were addressed across many geographical zones, served to emphasize the growing use of paleoenvironmental archives to understand human-environment interactions. Reflections on the meeting by recipients of PAGES support gave a flavor of the intellectual atmosphere and rapport generated during the meeting. One recipient commented that the meeting was timely: taking place not only when ecosystems are increasingly threatened by rapid climate change and human activities but when scientific communities across the globe are trying to find the best possible approaches to mitigate these effects. This meeting was a significant step toward our efforts for a comprehensive understanding of the human-climate-ecosystem interactions during the 21st century that help promote societal and ecosystem resilience against future climate change. The use of a range of proxy indicators to understand ecosystem response to climate and human drivers can help us develop not only management tools but also our theoretical understanding of ecosystem responses to multiple and complex forcing.

references

Dearing J et al. (2012) PNAS Plus 109(18): E1111-1120

A successful paleoclimate reconstruction based on proxy archives rests not only on understanding how regional climate and local weather patterns are related to variability of the climate proxy, but equally on the understanding of local processes that influence how the climate signal is captured in the archive. Speleothem deposits in caves yield a wealth of proxy data that can be related to changes in atmospheric circulation, precipitation and vegetation.

Monitoring cave environments is key to understanding relationships between weather and the processes that affect calcite precipitation inside caves. These include for example knowledge of the production rate of CO2 in the soil zone and its movement in and out of caves, the relationship between rainfall and the composition and movement of groundwater, and the impact of seasonal changes on the precipitation of carbonate as speleothem. Setting up and maintaining reliable cave monitoring programs presents a challenge in wet caves, which are often remote and difficult to access even for experienced speleologists.

Back in 2009 we held a first workshop on cave monitoring techniques in Gibraltar to discuss the technology that was available and share experiences in best practices among the small group of researchers in this field. Three years later many more groups are involved in cave monitoring and have acquired considerable expertise. In April 2012 we held the 2nd International Cave Monitoring Workshop in Innsbruck bringing together scientists and PhD students from 14 countries to discuss new ideas in methodology and instrumentation.

The workshop provided an informal discussion forum for exchange of experiences covering all practical aspects of cave monitoring. Four main themes were discussed: strategies for monitoring the hydrology and meteorology of cave systems, instrumentation and data logging, sampling and analysis protocols, and in-situ studies of carbonate precipitation and other cave processes. It is clear that some challenges still remain, such as finding a reliable way to precisely measure the relative humidity, and avoiding unwanted interference by insects and other animals as well as humans. However, the three years since the first workshop saw significant advances in the ability to carry out automatic logging and sampling of key parameters using ingenious, custom-built instruments.

Cave monitoring is now being actively carried out in many cave systems over the world (e.g. Fig 1) and clearly shows that every cave has its own “personality” that takes several annual cycles to properly characterize and evaluate. Once this is done, features of the chemical proxy record preserved in speleothem can then be assigned to specific local processes, and thus improve the reliability of climate reconstructions from proxy records.

A day trip to Spannagel Cave, an 11 km-long high-alpine marble cave hosting Europe´s highest show cave, marked the end of the workshop. The workshop organizers are grateful for financial support from the Office of the Vice Rector for Research, the Faculty of Geo- and Atmospheric Sciences and the Research Centre Geodynamics and Geomaterials (all University of Innsbruck, Austria) and Gemini Data Loggers (UK).

Figure 1: Dripwater collection in Obir Cave, Austria. Photo credit: Robbie Shone (shonephotography.com).

Climate refugia, i.e. areas where populations of a species avert extinction during periods of unfavorable regional climate, may play a central role in maintaining regional-to-global biodiversity. Paleoecologists and biogeographers have a long-standing interest in refugia as a means to explain latitudinal migration or stasis of the geographic distribution of a species through glacial periods and the resulting relictual distributions and endemism (Hampe and Jump 2011). More recently, the burgeoning field of phylogeography has demonstrated the value of genetic information to complement the fossil record in understanding past species distributions. This has lead to increased recognition that far more species than previously thought may have maintained small and scattered populations through the Last Glacial Maximum in refugia situated at relatively high latitude (Stewart et al. 2010). Indeed, a generally low rate of extinction attributable to the dramatic climate change of the Quaternary is not congruent with high rates of future extinction that are projected by many species distribution models (Botkin et al. 2007). The existence of climate refugia in heterogeneous landscapes may provide one solution to this conundrum and contribute to important assessments regarding the risks of future climate change to biodiversity. Specifically, a better knowledge of the functioning and dynamics of historical climate refugia can enhance our understanding of how current populations may react to future climate changes, help with identifying potential refugia for species of concern, and improve our understanding of biotic responses to continued climate warming (Keppel et al. 2012).

We convened a three-day workshop, with support from PAGES and the University of Oregon, to bring together experts from diverse disciplines that provide complementary insights into the identification, characterization, and importance of climate refugia. The workshop engaged 33 participants from 10 countries with backgrounds in paleoecology, climatology, phylogeography, biodiversity research, and species distribution modeling. Three days of meetings were used to discuss advances within each discipline and opportunities for transdisciplinary research approaches.

Figure 1: Three broad approaches to studying past species responses to climate change may be used jointly to exploit the complementary strengths of each approach to obtain the most complete reconstruction of historical refugia.

There remains much untapped potential to study climate refugia by using a joint inference across multiple disciplines (Fig. 1). Joint analysis of data across disciplines enables a clearer and more robust picture of species history, as the strengths of the different disciplines are combined. For instance, the fossil record can be used to evaluate the performance of paleoclimate simulations and species distribution models (Varela et al. 2011). Second, hindcasted species distributions have been used to generate hypotheses that can be tested by phylogeographic studies (Richards et al. 2007), or simply to reveal past range dynamics that can explain the current distribution of genetic lineages (e.g. Hugall et al. 2002). The successful application of species distribution modeling to the study of refugia requires not only reliable paleoclimate estimates from coarse-resolution models, but also realistic downscaling of relevant variables over complex terrain in the present and the past (Dobrowski 2011). Phylogeography can notably help to detect small populations (cryptic refugia) and reveal the direction of past population expansions that went undetected in the fossil record, whereas the fossil record can constrain the timing of such expansions and detect past range contractions (i.e. local extinctions; Hu et al. 2009). Where sufficient data exist, a network of fossil sites may be interpreted with respect to the refugia inferred from genetics to constrain the spatial and temporal patterns of postglacial expansion, as has been done for Fagus sylvatica in Europe (Magri et al. 2006). Few studies to date have attempted joint inferences across all three approaches, and a quantitative framework that considers the strengths and weaknesses of each approach is needed for rigorous assessment of past species refugia and migration patterns. Such studies are likely to provide the most informed view of how individual species persisted through the Quaternary and, potentially, into the future.

selected references

Full reference list online under: http://pastglobalchanges.org/products/newsletters/ref2012_2.pdf

Dobrowski SZ (2011) Global Change Biology 17: 1022-1035

Hampe A, Jump AS (2011) Annual Review of Ecology, Evolution, and Systematics 42: 313-333

Hu FS, Hampe A, Petit RJ (2009) Frontiers in Ecology and the Environment 7: 371-379

Keppel G et al. (2012) Global Ecology and Biogeography 21: 393-404

Magri D et al. (2006) New Phytologist 171: 199-221

Figure 1: Ecosystems, such as the Tibetan Plateau depicted here, provide a wide variety of ecosystem services such as clean water, recreation space and fodder for grazing. Information on the response of these goods and services to environmental change is recorded in natural archives and is essential for the sustainable management of these resources. Photo: Shonil A. Bhagwat.

The first meeting of the PAGES Focus 4 Biodiversity Theme was co-sponsored by PAGES and the Oxford Martin School Biodiversity Institute. The overall aim of the meeting was to bring together paleoecologists, modelers and neo-ecologists whose research contributes to understanding the dynamics over time and space of biodiversity and ecosystem services. Forty people attended the meeting representing 14 different countries and five continents.

The three-day meeting was split into seven sessions. The first four focused on the presentation of paleo-data relevant to the four key ecosystem services categories (Box 1). Two sessions focused on using the past to assess biodiversity risks in the future, and modeling of long-term data for managing ecosystem services. The final session examined the use of long-term data in ecosystem service valuation and management tools.

In addition to the plenary presentations there were also two breakout sessions, which stimulated discussion on (i) the different types of paleoecological data that are relevant to assessing ecosystem services through time and (ii) the databases and sources already available to enable landscape-scale reconstructions, and the identification of data gaps. The overall conclusion from these breakout sessions was that there is already a vast wealth of excellent data and models available for assessing ecosystem function and service provision through time. The major challenge is to determine the appropriate means to disseminate this information to policy makers, habitat managers, and other academics. In particular, the participants discussed the need to devise new methods to present paleodata in a format that is more accessible, possibly through the development of new data management tools and better web-portals.

The main outputs of the meeting will be an edited volume in The Holocene entitled Dynamics of Ecosystem Services Through Time: Looking to the Past to Plan for the Future. A policy brief is also in progress to communicate the need for a long-term perspective in national and international ecosystem assessments. Future planned activities of the PAGES Biodiversity Theme include a workshop at the International Ecology Congress (INTECOL) 2013 and a second Working Group meeting in Oxford, UK. The recent establishment of the International Panel on Biodiversity and Ecosystem Services (IPBES) renders this PAGES Theme and its focus on biodiversity and ecosystem services extremely timely.

Box 1

Ecosystem services are benefits that people obtain from ecosystems and are divided into four categories:

• Supporting services

e.g. dispersal of seeds and pollen, cycling of nutrients, primary production

• Provisioning services

e.g. supply of food, water, pharmaceuticals, energy

• Regulation services

e.g. crop pollination, carbon sequestration, waste decomposition and detoxification

• Cultural Services

e.g. recreational and cultural experiences, scientific discoveries

Figure 1: Excavation trench from the Late Pleistocene archeological site Sowin in the Silesian region of Southwestern Poland. The profile shows three main stratigraphic units (recent soil, eolian sands, and sand-clayish sediments) and anthropogenic charcoal deposition. Photo by A. Wisniewski.

Geoarcheology brings together many disciplines such as geology, geomorphology, archeology, paleobotany or zoology. The traditional geoarcheological approach is based mainly on geological and soil science methods, but during the last 20 years detailed microstratigraphic studies and analyses of microfacies have become more and more important (Courty 2001). These approaches were recognized as essential to recover and understand the full cultural and environmental potential of archeological deposits (Goldberg and Macphail 2006).

The main aim of this workshop was to initiate scientific discussion on the new challenges for geoarcheology in Central Europe. Scientifically, the focus was on ongoing environmental archeology research in southern Poland and the northern Czech Republic, and their implications for paleoclimate research. The presentations mainly concentrated on the Late Pleistocene and Middle to Late Paleolithic (130-12 ka BP), for which archeological evidences are more frequent than for earlier periods.

The organizers had invited a range of specialists from the Czech Republic and Poland to discuss “key” questions of the Late Pleistocene stratigraphy and Paleolithic evidences from southern Poland. Topics addressed ranged from subsistence strategies of Late Paleolithic hunter groups to the MIS3-MIS1 stratigraphical records in the region (Połtowicz-Bobak 2009; Wiśniewski et al. in press; Bobak and Poltowicz-Bobak, in press). In addition, applications of relatively new methodological approaches for the field were presented, such as microstratigraphy, isotopic studies or GIS analyses (see Skrzypek et al. 2011). In total, nine presentations raised questions about chronological accuracy in the context of terrestrial and marine data as well as chronostratigraphy from the view-point of archeology (e.g. Fig 1; Wiśniewski, University of Wrocław; Bobak, University of Rzeszów) and sedimentology (Lisa, Institute of Geology, Academy of Sciences of the Czech Republic; Kalicky, University of Kielce), subsistence strategies in the context of environmental changes (Łanczont, University of Lublin; Madeyska, Polish Academy of Science; Warszawa, Połtowicz-Bobak, University of Rzeszów; e.g. Boguckyj et al. 2009, Sytnyk et al. 2012) and on the paleozoological records of environmental change (Nadachowski, Polish Academy of Sciences; Kraków, University of Wrocław; Nadachowski 2011). Finally, Iwona Hildebrant-Radke (Mickiewicz University Poznań) presented new methodological aspects for the use of GIS in geoarcheological investigations (Jasiewicz and Hildebrand-Radke 2009). The presentations were followed by plenary discussions.

The major outcomes from the meeting in Poznań are plans for a new cooperation, especially within the scope of the study of the Late Paleolithic in the historical region of Silesia. One example is the transfer of methodological knowledge between institutes from the Czech Republic and Poland. The participants agreed to build a network for sharing such information. Until now, the exchange of knowledge between the Polish and Czech groups was rather scant and it was decided that an important step to improve it would be to designate a contact person in each country who will share the information about forthcoming meetings. The contact persons for the Polish part are Katarzyna Issmer and Andrzej Wiśniewski. The contact person on the Czech side is Lenka Lisa. Another approach to facilitate communication in the scientific community is the creation of two virtual groups on the social network Facebook with the title “Quaternary Group” (www.facebook.com/#!/groups/253485648040066/) and “Zooarchaeology and Paleonthology” (www.facebook.com/#!/groups/paleontologie/). Also, a scientific platform for Central Europe was set up (http://geoinfo.amu.edu.pl/sas/en/egp/index.php).

This workshop was supported by the Polish Association for Environmental Archeology and the A. Mickiewicz University in Poznań, and was endorsed by PAGES.

references

Boguckyj AB et al. (2009) Quaternary International 198: 173-194

Jasiewicz J and Hildebrandt-Radke I (2009) Journal of Archaeological Science 36: 2096-2107

Nadachowski A et al. (2011) Quaternary International 243: 204-218

Skrzypek G, Wiśniewski A and Grierson PF (2011) Quaternary Science Reviews 30: 481-487

Wiśniewski A et al. (in press) Quaternary International, doi: 10.1016/j.quaint.2011.09.016