Most of Madagascar has undergone serious deforestation during the last 40 years, chiefly from slash-and-burn practises by indigenous peoples. This loss of forest has led to extreme soil erosion in the Mangoky River basin, as evidenced by the many sandbars located within the river channel. Silt-laden, greenish-tan Lake Ihotry is clearly discernible south of the river. Between the lake and the coast is a rather large, whitish area of sand interspersed with silt-laden ponds. The southern portion of the delta is dominated by successive barrier island and spit formation. In contrast, the northern, protected portion of the delta is dominated by tidal passes and mangrove swamps.