The effects of fires on plants and wildlife species diversity and soil physical and chemical properties at Aberdare Ranges, Kenya

Abstract

Abstract. Njeri WF, Githaiga JM, Mwala AK. 2018. The effects of fires on plant and wildlife species diversity and soil physical and chemical properties at Aberdare Ranges, Kenya. Asian J For 2: 25-38. Forest fires have devastating impacts on the biodiversity and biophysical elements of forest ecosystems. Yet, little is known of the impacts of forest fires in a lesser-known region such as Kenya. This study was aimed to determine the effects of fires on species diversity (plants, animals, birds), and soil physical and chemical properties at the Aberdare Ranges forest, Kenya. Data were collected on five sites that experienced fires in 2002, 2009, 2012, 2013, and 2014 from both burnt and unburnt areas. Point Centered Quarter and quadrant methods were used for woody vegetation sampling and herbaceous vegetation sampling, respectively. Foot count was done for animal census and point count for birds. The data showed that the herbaceous vegetation in burnt sites had significantly higher species diversity than the unburnt sites in the areas that experienced fire before 2014. The fire had triggered the regeneration of the herbaceous plants. The burnt sites had a significantly higher percentage cover. The fire had an immediate adverse effect on the population of animals as demonstrated on the site consumed in 2014. No animal species were found on the site seven days after the fire when data was collected. The animal diversity was proportional to the vegetation density caused by the vegetation regeneration due to fires. All the burnt sites had fewer birds than the unburnt sites. Effects of fires were prominent in the upper layer of the soil for all the soil properties under study. Burning caused an increase in pH, potassium, organic carbon and cation exchange capacity. The study demonstrated that fires lead to an immediate adverse effect on vegetation, wildlife and soil chemical properties. Postfire management is necessary on sites that have recently experienced fires to rehabilitate them. Authorities responsible for the management of forests must ensure that people are kept out of those sites to allow vegetation to recover without interference. Reforestation can also be done on the burnt sites to increase plants and habitat for the wildlife.