The Tumbes-Piura dry forests is an arid tropical ecoregion along the Pacific coasts of southern Ecuador and northern Peru. The ecoregion contains many endemic species of flora and birds adapted to the short wet season followed by a long dry season. Threats include extraction of wood for fuel or furniture, and capture of wild birds for sale.
The terrain includes coastal lowlands, low undulating hills and the foothills of the Andes. The soils in the lower regions are mostly sand and clay formed during the recent Holocene epoch. Higher up the soils are made of Precambrian amphibolites, Paleozoic granites, Devonian quartzites and black slate, and Carboniferous dark limestone, sandstone and lutites. The main rivers, which mostly rise in Ecuador and flow throughout the year, are the Guayas, Zarumilla, Tumbes, Piura and Chira rivers. Other streams are seasonal, flowing only in the rainy season.
Climate
The climate is dry. The Köppen climate classification is "BWh": arid; desert; hot arid. Average annual temperature is. At a sample location at coordinates mean annual temperature is just under, with average maximum of and minimum of. Mean monthly temperatures range from in July–August to in February–March. There is a rainy season from January to March and a marked dry season. Typical annual rainfall is. The El Niño–Southern Oscillation is a major event in the region, when rainfall increases and thousands of plants species germinate, providing food for many animal species.
There is a wide range of habitats, including desert areas with shrubs and cactuses and dense thorn forests. Many species of flora are endemic, adapted to the arid conditions. Large areas are covered by seasonal dry forests that lose their leaves after the rainy season. Common species in the dry forests include Loxopterygium huasango, Handroanthus billbergii and holy wood, all threatened by human exploitation. Other common species are Ziziphus thyrsiflora, Caesalpinea corymbosa, Capparis angulata, Bombax discolor, Pitthecellobium multiflorum and Geoffroya striata. The ceibal forest mainly holds the endemic Ceiba trischistandra. The chaparral is mainly made up of shrubs such as papelillo, cacti and the overo. The area is rich in mesquite, which capture and fix nitrogen in their roots, enriching the soil and assisting other species. The algarrobal'' is mainly composed of algarrobo. in southern Ecuador
The World Wildlife Foundation gives the ecoregion a status of "Critical/Endangered". In the past, the ecoregion suffered from extract of selected fauna and flora. This included capture of parrots and parakeets for sale as pets, hunting some mammals and reptiles for food, and extraction of wood for firewood, charcoal and timber. As of 2000 some recent improvements had been observed, in part due to El Niño effects and in part to establishment of the Cerros de Amotape National Park. The park management and other groups were working with communities to find ways to maintain biodiversity. Protected areas also include the Reserva del Noroeste biosphere reserve.