The range of low hills running south-west from Dar es Salaam to the border of the Selous Game Reserve attracts higher rainfall than the coastal plain and this has resulted in the development of evergreen forest with a poor ground flora on the mainly dry sandy soils. Three Forest Reserves comprise this site: Pugu Hills Forest Reserve (2,180 ha), of which less than 400 ha remains in reasonable condition; Kazimzumbwi Forest Reserve (4,887 ha), of which perhaps only 900 ha can be considered forest; and Ruvu South Forest Reserve (35,000 ha), of which only 10,000 ha can be considered forest. The north-eastern corner of Ruvu South comes within 1 km of the north-western end of Pugu and is only 2 km from the western edge of Kazimzumbwi. Forest composition varies considerably between the three reserves, largely due to the past removal of valued timber, but also reflecting differing soil and groundwater conditions. The only tall (35 m) emergents in Pugu are a few Antiaris toxicaria and Dialium holtzii in the Msimbazi valley. There are even fewer tall emergents in Kazimzumbwi, and Ruvu South is characterized by extensive Zanzibar–Inhambane scrub-forest that may be natural climax vegetation. There are also large stands of riparian forest in Ruvu South, as well as at least two swamps and areas of grass-covered flood-plain. The site has two major railway systems passing through it; the need to protect embankments and cuttings should help ensure some forest remains on the steeper slopes.Vikindu Forest Reserve (1,599 ha, much of which is plantation), to the south of Dar es Salaam, was known to hold Anthus sokokensis, but is so badly degraded that attempts to protect it were abandoned and it has not been included in this site.
See Box and Tables 2 and 3 for key species. Circaetus fasciolatus is a low-density resident. Anthus sokokensis is known from Ruvu South, but can only be a rare, low-density species. Zoothera guttata is a regular passage migrant, particularly in May when birds are moving north from their southern breeding grounds. Sheppardia gunningi is a locally common resident at all three forests and Ruvu South may hold Tanzania’s largest population of this species. The forest birds of Pugu and Kazimzumbwi are well known. Those of the forest of Ruvu South have received far less attention, but the avifauna of the woodlands is better known and includes such localized species as Glaucidium capense, Neafrapus boehmi, Pachycoccyx audeberti, Campethera bennettii and Pyrenestes minor, as well as uncommon migrants such as Coturnix chinensis. Pogonocichla stellata is a regular migrant from montane habitats. Other visitors from higher altitudes have included Sarothrura elegans, Columba larvata, Coracina caesia, Zoothera gurneyi and Andropadus milanjensis. Regular Afrotropical migrants include large numbers of Cossypha natalensis (which is also a low-density resident) and small numbers of Pitta angolensis. Trichastoma rufipennis puguensis is locally endemic.
Non-bird biodiversity: A population of Loxodonta africana (EN) is associated with Ruvu South and may well move between this site and the northern approaches of the Selous Game Reserve.
Pressure/threats to key biodiversity
The close proximity to Dar es Salaam has always placed high pressure on these Forest Reserves. In addition, the Pugu Hills hold one of the world’s largest and most easily accessible deposits of kaolin. Maintaining forest on the hills is important for water-catchment management. Repeated illegal invasions of Kazimzumbwi Forest Reserve have been well publicized. The Wildlife Conservation Society of Tanzania, in conjunction with the Forest Department, CARE and WWF, are running a long-term conservation programme in the area. The extensive plantations of exotic Cassia and Eucalyptus within Pugu should be removed and replaced with indigenous trees. There are kaolin deposits under the Pugu Hills, the exploition of which would necessarily result in destruction of habitat.
Mzunguko wa vilima vya chini unaoelekea kusini magharibi kutoka Dar es Salaam hadi mpaka wa Hifadhi ya Selous Game huvutia mvua nyingi kuliko uwanda wa pwani na hii imesababisha maendeleo ya msitu wa kijani kibichi na mimea duni ya ardhi kwenye udongo wa mchanga kavu. Hifadhi tatu za misitu zinajumuisha eneo hili: Hifadhi ya Misitu ya Pugu Hills (2,180 ha), ambayo chini ya 400 ha inabaki katika hali ya busara; Hifadhi ya Misitu ya Kazimzumbwi (4,887 ha), ambayo labda 900 ha tu inaweza kuchukuliwa kuwa msitu; na Hifadhi ya Msitu wa Ruvu Kusini (35,000 ha), ambayo 10,000 ha tu inaweza kuchukuliwa kuwa msitu. Sehemu ya kaskazini mashariki ya Ruvu Kusini iko ndani ya kilomita moja kutoka mwisho wa kaskazini magharibi mwa Pugu na ni kilomita mbili tu kutoka ukingo wa magharibi wa Kazimzumbwi. Muundo wa misitu hutofautiana sana kati ya hifadhi tatu, hasa kutokana na kuondolewa kwa mbao zenye thamani, lakini pia kutafakari hali tofauti za udongo na maji ya chini ya ardhi. Mimea mirefu tu (35 m) inayoibuka huko Pugu ni Antiaris toxicaria na Dialium holtzii katika bonde la Msimbazi. Kuna hata emergents wachache mrefu katika Kazimzumbwi, na Ruvu Kusini ni sifa ya Zanzibar <unk> Inhambane scrub-msitu mkubwa ambayo inaweza kuwa asili kilele mimea. Pia kuna misitu mikubwa ya kando ya mto katika Ruvu Kusini, pamoja na angalau mabwawa mawili na maeneo ya uwanda wa mafuriko uliofunikwa na nyasi. Eneo hilo lina mifumo miwili mikubwa ya reli inayopitia; uhitaji wa kulinda mabwawa na vichaka unapaswa kusaidia kuhakikisha baadhi ya misitu inabaki kwenye mteremko mkali.Hifadhi ya Msitu wa Vikindu (1,599 ha, ambayo ni mimea), kusini mwa Dar es Salaam, ilijulikana kushikilia Anthus sokokensis, lakini imeharibiwa sana hivi kwamba majaribio ya kuilinda yaliachwa na haijajumuishwa katika tovuti hii. Angalia sanduku la 2 na meza ya 3 kwa spishi muhimu. Circaetus fasciolatus ni mkaaji wa wiani wa chini. Anthus sokokensis inajulikana kutoka Ruvu Kusini, lakini inaweza tu kuwa nadra, spishi ya wiani wa chini. Zoothera guttata husafiri mara kwa mara, hasa mwezi wa Mei wakati ndege wanapohamia kaskazini kutoka maeneo yao ya kusini ya kuzaliana. Sheppardia gunningi ni mkaaji wa kawaida wa maeneo yote matatu ya misitu na Ruvu Kusini inaweza kuwa na idadi kubwa zaidi ya spishi hii nchini Tanzania. Ndege wa msitu wa Pugu na Kazimzumbwi wanajulikana sana. Kwa upande mwingine, ndege wa misitu ya Ruvu Kusini wamepokea umakini mdogo, lakini avifauna ya misitu inajulikana zaidi na inajumuisha spishi kama vile Glaucidium capense, Neoptera bohemi, Pachycoccyx audeberti, Campithera bennetti na Pyrenees minor, pamoja na wahamiaji wasio wa kawaida kama vile Coturnix chinensis. Pogonocichla stellata ni mhamiaji wa kawaida kutoka makao ya milimani. Wageni wengine kutoka maeneo ya juu zaidi wamehusisha Sarothrura elegans, Columba larvata, Coracina caesia, Zoothera gurneyi na Andropadus milanjensis. Wahamiaji wa kawaida wa Afrotropical ni pamoja na idadi kubwa ya Cossypha natalensis (ambayo pia ni mkazi wa wiani wa chini) na idadi ndogo ya Pitta angolensis. Trichastoma rufipennis puguensis ni ya kienyeji. Loxodonta africana (EN) ni jamii ya ndege wa asili wa Afrika, ambayo huishi katika eneo la Ruvu Kusini na inaweza kusafiri kati ya eneo hili na njia za kaskazini za Hifadhi ya Selous Game. Shinikizo/tisho kwa utofauti wa kibiolojia muhimu Ukaribu wa karibu na Dar es Salaam daima umeweka shinikizo kubwa kwenye Hifadhi hizi za Msitu. Kwa kuongezea, Milima ya Pugu ina mojawapo ya madini makubwa zaidi ya kaolin ulimwenguni na yanayopatikana kwa urahisi. Kudumisha misitu kwenye milima ni muhimu kwa ajili ya usimamizi wa maji. Uvamizi wa mara kwa mara wa kinyume cha sheria wa Hifadhi ya Msitu ya Kazimzumbwi umefichuliwa sana. Shirika la Uhifadhi wa Wanyama wa Pori la Tanzania (WCST) pamoja na Idara ya Misitu, CARE na WWF, zinaendesha programu ya muda mrefu ya uhifadhi katika eneo hilo. Mimea mikubwa ya Cassia na Eucalyptus ya kigeni ndani ya Pugu inapaswa kuondolewa na kubadilishwa na miti ya asili. Kuna madini ya kaolin chini ya Milima ya Pugu, ambayo kutumiwa vibaya kwa lazima kungesababisha uharibifu wa makao.