Paleoecology

The palaeoecology palaeoecology or is the study of the fossil habitats and their communities, so consider the ecosystems of the geological past.

The tray is usually no separate academic discipline but integrated in the allied disciplines such as geography, paleontology, archeology or archaeobotany.

Research area and research objectives

In the paleoecology it comes to illuminate the context of environment, climate and human influences, namely on the basis of environmental and climate changes in the past. The paleoecology tries to answer the question of how the environment has evolved and how in the course of these developments, the current environment has emerged.

It is essential to long-term observation of the interaction of climate and environment. From this, conclusions about the laws of such interactions can be drawn, the future climatic and vegetation developments are relevant for the assessment. The distinction between natural and human influences on the landscape history is important for the question of conservation.

In order for the paleoecology not only satisfies the general scientific curiosity, but is also relevant for the prediction and assessment of future vegetation, climate and landscape developments.

Methodology

Research material

Since the climate and vegetation of the past are not accessible directly or in reliable records, the paleoecology has a "natural archives " search in which traces of past vegetation and climate changes can be found. Examples of such natural archives are deposits in lakes and bogs, as well as the glacial ice in Greenland.

Using the example of lake sediments one can keep in mind what type deposits are found in a lake: abiotic entry ( erosion); terrestrial biotic record (pollen, insects ...); biotic aquatic entry ( algae, crustaceans, foraminifera ... ).

Of great importance for the study of environmental and climate development in the desert areas of the Southwestern United States and Mexico during the last 40,000 years, the analysis of waste pile is (English: pack rat midden ) of the American bush rat.

Data collection

Paläoökologen investigate sea and / or freshwater sediments from cores or geological outcrops. Here, the operation is exemplified by the study of pollen deposits ( Palynology ).

To analyze the core samples at certain intervals a small amount is taken out and cleaned the material for a specific procedure laid down in several steps. This aggressive acids and bases are used as the pollen however, were resistant, while the remaining deposits thus can be resolved for the most part.

The thus purified deposition is then examined under a microscope. The pollen can be identified, that is, assigned to a particular plant species, and counted. The frequency of certain types of pollen is recorded in pollen diagrams. Plant pollen are of course only a part of what you find in the deposits and can give a indication of the environment at that time. Macroremains ( piece of tree bark, etc.) are important to assess whether the pollen really come from the vicinity of the lake or have been approached with from afar by the wind. Other researchers focus on more botanical, zoological or physical indicators, which can be found in the cores and the conclusions on the environmental permit (eg diatoms, cladocerans, chironomids, volcanic ash, sediment grain size, etc.)

Dating question

For the dating of the deposits there are two basic ways:

• Some deposits are different seasonal. Therefore, annual layers can be distinguished, which can also be counted.
• Based on the content of radioactive carbon isotopes can be identified C14 age.

These two reference systems do not match completely. Today, the C-14 data, mainly as far as calibrated on annual ring counts that one can derive the absolute solar years, with certain variations.

The ice cores from Greenland serve as long-term temperature archive. Because of the oxygen isotopes in the ice and the dust content, conclusions can be drawn regarding the temperature development. Therefore, the paleoecology has resulted in a curve of the long-term trend in average temperature. This curve is considered to be very reliable and is used as a reference curve, fit their own data collections in the Paläoökologen. The reference curve thus making it a dating help.

Requirements

The paleoecology must be able to interpret the traces of the past at all meaningful, it may recognize that the resulting plant remains (pollen and macro- remains) can be considered only partially representative of the former vegetation because

• The plant species have species-specific demands on the location and thus their occurrence are merely an indicator of the climatic conditions at the site.
• The morphology of the plants and their species-specific demands on the environment over time may have changed.
• Everything under the condition that the climate and vegetation in a given area are each in equilibrium.

Interpretation

The pollen diagrams provide information on the changes in vegetation in time. When interpreting it comes to seek reasons for these changes. But of course, comes the climate in question, but also the interplay of different plant species, the impact of humans and more.

It should be noted in the interpretation of that set many developments after a delay: After a changing climate, the plants need time to wander, and to establish themselves in new places.

Very nicely seen in the paleoecology that we are dealing with a network of knowledge, must fit the individual parts together. It tries, pollen, macro remains, insects, C14 - dating, independent climate data from oxygen isotopes, etc. together into a single image. The more you already know from other sources about a time or a region, the better protected and detailed the conclusions that can be drawn from our own data.