KihansiGorge

Local climate change in a Biodiversity hotspot
	The Main Kihansi Waterfalls and their spray clouds which had an important influence on the microclimate of the area

The environmental monitoring of the Lower Kihansi Hydropower project in the Udzungwa Mountains, Tanzania, brought together a team of international scientists to examine the impact that the project would have upon the ecosystem of the Kihansi Gorge. Located in the Eastern Arc global biodiversity hotspot, the moist forests of the 4km long, steep-sided gorge provide habitat for a diverse range of plants and animals found only in isolated forest pockets in this part of the world. In addition, the scientists soon discovered additional species which were previously unknown to science, and which appeared (through surveying the surrounding gorge forests) to be confined to small areas of the Kihansi Gorge only.

Offloading data in the field with Amos Mwalo and Homas Msofu.

A critical component of the monitoring activity was to examine environmental changes over time associated with the diversion of the Kihansi River for power generation. Six Skye DataHog1s were initially employed in 1997 to monitor the microclimate of the forests, and were soon added to with the purchase of 5 DataHog2s to expand the monitoring activities, including one fitted with tensiometer channels to sample soil moisture in the critical habitat zones around the foot of the dramatic waterfalls. The long battery lives, and automatic logging of the sensors, also allowed them to be left in the field for long periods of time to sample climatic seasonality of the study area over a number of months without the need for any on-site maintenance or intervention.
Collecting microclimatic data before and after changes in gorge hydrology has enabled James Taplin (coordinator of the microclimatic and vegetation monitoring components) from the Centre for Ecology, Law & Policy at the University of York, to accurately quantify the magnitude and location of these alterations, and relate them to observed changes in vegetation parameters over the same period. Whilst preliminary, these results have important implications for the response of other biodiversity-rich forests in the Eastern Arc Mountains to the wider impact of Global Climate Change.

GIS interpolation of the temperature data collected in the gorge in 1997.

The boundary of the forest is marked, as is the Kihansi river and various vegetation sampling points. It shows the conditions at 9am during the dry season. The hotter conditions outside of the forest at the foot of the falls can be seen in red, as can the much cooler condiitons around the main falls at the head of the gorge in blue/purple. Sampling didn’t always extend to the forest boundary all the way up the gorge, so interpolated conditions outside of the forest (except for at the foot of the gorge) should be ignored.

Thanks to James Taplin for contributing to SkyeNews

For more information please contact James Taplin: jrdt3@york.ac.uk

The Equipment
The Skye DataHog1 has now been superceded by the DataHog2. DataHog2 is a cost-effective versatile multi-channel datalogger, entirely suitable for this application in particular, but can be easily configured for most sensors and projects. DataHogs are designed for outdoor environments without the need for purchasing additional waterproof enclosures. DataHog systems are supplied with plugs and sockets, so there is no time and effort wasted searching for wiring pages in a manual. Plugs and sockets are ideal for ‘projects on the move’. Quick to set up and you know you have connected them up correctly - no wondering if you have put the wrong wire in the wrong terminal!
Some models have integral RH and Air Temperature sensors, but we can also supply DataHogs with ‘plug-in’ versions.
Skye RH & T probes use quality components and a humidity sensing element that is designed for use in high humidities, ie. >95%, such as is found in the Kihansi Gorge.