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Gobabeb Research & Training Centre

Ecological Long-Term Monitoring

The value of environmental research does not only lie in increasing understanding of a particular phenomena at a particular time, but also in generating long term data sets. By repeating measurements at different locations and across time, comparison is possible – we get an idea of what is changing over space and time. Monitoring has to be ongoing to detect change, and a track record of data is required in order to be able to guide planning concerning how to respond to change: reverse, mitigate or adapt to it. Monitoring is equally important in places that do not change significantly; we need to understand stability and its reasons, as much as we need to understand change and its causes.

Gobabeb has been conducting ecological monitoring for five decades. Monitoring started with the establishment of a weather station and has expanded over the years to include many different biotic and abiotic aspects of the Namib Desert. Over the Centre’s long history data has been collected on geophysical changes, growth of individual flora species, plant and animal population dynamics, and patterns of productivity. The research staff at Gobabeb undertakes these measurements on an hourly, daily, monthly, seasonal, annual or decadal basis to build up a data base. Long-term monitoring at Gobabeb straddles both time and space, between different projects and initiatives, thus forming a true network concerning long-term environmental monitoring.

Groundwater

Two boreholes (one in the main river channel and the other in the flood plain) were drilled upriver of Gobabeb in 2005. Time Domain Reflectometry (TDR) probes in the two boreholes monitored infiltration, transmission losses, percolation, conductivity and effective porosity at a series of depths. The data was downloaded every 6 days and sent to Israel for analysis. As per the project aims, the purpose of this data collection was to fill in the information gap about what happens between the surface flow and the groundwater -- what are the factors that influence how much water from floods is able to replenish the underground aquifers? How much water is lost? How is it lost? These factors directly impact the long-term water supply, but until now very little research has been done to characterize them.

The WADE project continued at Gobabeb through December 2007. Since then, the hydrological research has continued under the CDR project . For this project, seven new boreholes were drilled in April 2007. Each borehole has a levelogger, which measures the depth of the water table. The purpose of the CDR project is to investigate relationship of water flow between the flood plain and river channel during recharge flood events. The project will be looking at lateral flow velocities along and across the stream channel by injecting friendly and non-toxic tracers into boreholes and collecting water samples from the others. This data will be used to measure direction and velocity of the water flow.

Tenebrionid beetles monitoring

When Dr. Charles Koch first visited the site of Gobabeb in 1958, he was so struck by the impressive diversity of beetles that he began work to establish a research station in the area. Research on this fascinating array of invertebrates has thus been a part of Gobabeb since its founding. The studies of ground-dwelling Arthropods, particularly those of the beetle family Tenebrionidae, have been carried out at Gobabeb since the 1960s. The main objective of these studies is to investigate the population dynamics of different surface-dwelling arthropod species, particularly Tenebriodnid beetles, in different ecosystems. These ecosystems include the Kuiseb Riverbed; the Interdune; the Gravel Plains;andthedune slip face, slope (upper, middle, lower and interdune) and plant hummock. Numerous traps are set-up at different sites in each of these ecosystems and monitored on weekly and bi-monthly basis by Gobabeb’s research technicians and interns. We monitor Tenebrionids and others because of their ecological importance as soil engineers. Population decline of one or more species can be correlated to different climatic and environmental conditions adding to our understanding of ecological relationships in the Namib Desert.The data and results produced can provide a quick reference for visiting researchers and students, film teams and other visitors wanting to use the center’s information resources.

Dune morphology (Helga Dune)

Gobabeb has monitored Namib dune dynamics continuously since 1970 on an annual basis. This research has revealed long-term geomorphological and other environmental processes that affect, or are in some way affected by, changes in the configuration of the dunes. For example, it has been suggested that the extraordinarily high diversity of tenebrionid beetles in the Namib Desert can be explained by the mobility of the sand dunes. The Namib sand sea consists of many different types of dunes, each with different configurations and dynamics, changing along an east-west gradient. The middle of the dune field, such as the area around Gobabeb, is dominated by long, linear dunes. In order to understand and predict major landscape changes, it is important to know how aeolian processes affect dunes in the area around Gobabeb and elsewhere in the dune sea, as well as their interaction with processes such as flooding of the Kuiseb River.

Welwitschia growth

This ongoing study aims to collect long-term ecological data on the Namib Desert perennial Welwitschiamirabilis.Thewelwitschia is unique in the plant world. Genetically, Welwitschia are not closely related to any other plants; they are taxonomically placed into their own family 'Welwitschiaceae.' Each plant has only two broad strap-like leaves that lie on the ground and grow continuously throughout the plant's life, tearing into pieces over time. Welwitschia can live for hundreds of years with the oldest specimens estimated to be 1500 to 2000 years old. Though they are classified as gymnosperms because they are cone-bearing they also have xylem (water conducting tissue), a trait specific to angiosperms. Welwitschia mirabilis has been described as a 'living fossil' and has survived since the Jurassic Period.

Gobabeb’s Research Technicians and interns do measurement of parameters such as size, growth and reproduction on an annual basis. Welwitschia growth monitoring has been carried out by Gobabeb researchers at Welwitschia Wash near Homeb as part of Gobabeb long-term ecological research since 1985. In 2004, more welwitschia plants were mapped at the Hope Mine area.

The purpose of the study is to monitor the health of welwitschia plants, as well as to observe potentially harmful factors such as fungal presence or browsing. This study adds to the long-term data baseline for the welwitschia, which allows better understanding of the plant's physiology and ecology in the light of natural variability in the environment and potential threats.

Namib Plain Grass Census

Rainfall in the Namib Desert usually comes from isolated convective clouds that are spaced widely apart. Rainfall is also highly unpredictable. Thus, the occurrence of effective rain to stimulate plant growth cannot be predicted for any year or location. Individual rain clouds moving across the Namib leave a green path of grass. The width and length of each rainfall path and the number of rainfall days varies greatly. Hence, adjacent locations may have the same productivity in a given year and via the seed bank and accumulated detritus the effect may be cumulative over years. The patterns of grass productivity become necessary to annually monitor this effect and to ensure the collection of data for future comparisons within and outside the Namib Desert.

The grass census is conducted along a network of 87 study sites, situated at approximately 5 km intervals from each other along 420 km of gravel roads in the Central Namib gravel plains. The census is conducted annually after the last rainfall event of the season, typically during late April or early May. Gobabeb's Research Technicians and interns measure grass growth at all sites.

Kuiseb River Flood

Gobabeb is situated n the banks of the the Kuiseb River. The Kuiseb is an ephemeral river and rather than flowing year-round, only flows after sufficient upstream rainfall events. In addition to playing a vital role in the desert ecosystem, ephemeral rivers may also be good indicators of global climate change. Gobabeb has collected data on the Kuiseb River flow pattern since 1963. This data allow researchers to describe the periods when flood events are most likely to occur and at what speed (velocity) and levels these events happen.

This dataset not only helps in predicting future climatic events but also aids in decision making on safety response measures in areas where extreme flood events my pose a threat to humans. Also, these data can be used in water abstraction decisions to ensure sustainable use of the underground water, which is recharged by flood events. Data is shared with all stakeholders in the Kuiseb Basin,including the Topnaar community, municipality of Walvis Bay, NamWater and the Directorate of Water Affairs and Forestry.

 

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