Research Article Human Influences on Tree Diversity and

Hindawi Publishing CorporationInternational Journal of Forestry ResearchVolume 2013 Article ID 305874 7 pageshttpdxdoiorg1011552013305874

Research ArticleHuman Influences on Tree Diversity and Composition ofa Coastal Forest Ecosystem The Case of Ngumburuni ForestReserve Rufiji Tanzania

J Kimaro1 and L Lulandala2

1 Tanzania Wildlife Research institute PO Box 661 Arusha Tanzania2Department of Forest Biology Sokoine University of Agriculture PO Box 3032 Morogoro Tanzania

Correspondence should be addressed to J Kimaro jegakihotmailcom

Received 19 June 2013 Revised 8 September 2013 Accepted 2 October 2013

Academic Editor Kristiina Vogt

Copyright copy 2013 J Kimaro and L Lulandala This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

This paper reports on the findings of an ecological survey conducted in Ngumburuni Forest Reserve a biodiversity rich forestreserve within the coastal forests of Tanzania The main goal of this study was to determine the influence of uncontrolledanthropogenic activities on tree species diversity and composition within the forest ecosystem It was revealed that economicactivities including logging charcoaling and shifting cultivation were the most important disturbing activities affecting ecologicalfunctioning and biodiversity integrity of the forest Further to this we noted that the values of species diversity compositionand regeneration potential within the undisturbed forest areas were significantly different from those in heavily disturbed areasThese observations confirm that the ongoing human activities have already caused size quality degradation of useful plantsenhanced species diversification impacts to the forest ecosystem and possibly negatively affected the livelihoods of the adjacentlocal communities Despite these disturbances Ngumburuni forest reserve still holds important proportions of both endemic andthreatened animal and plant species The study suggests urgent implementation of several conservation measures in order to limitaccessibility to the forest resources so as to safeguard the richness and abundance of useful biodiversity stocks in the reserve

1 Introduction

Habitat loss fragmentation and degradation are currentlythe most important threats to biodiversity conservationworldwide [1] Human activities have been widely reported tocontribute more to this problem compared to natural factors[2] Tropical forests especially those located in developingcountries are more vulnerable following the fact that themajority of forest adjacent communities are poor and dependdirectly on the forest resources to sustain their livelihood [3]Unsustainable use of forest resources for example throughlogging and shifting cultivation has potential impact onits ecological functioning due to sudden changes on theirstructure and composition [4] Emergence of invasive speciesand loss of ecosystem services resulting from the occurrenceof many woody pioneers and herbaceous species have been

observed in several disturbed forest ecosystems [1 5] Open-ing of forest canopies in the logged or burnt forests increaseslight levels which in some cases positively influences diversityindices [6] Understanding the factors related to human dis-turbance that affect the tree biodiversity and forest vegetationstructure can help conservation managers to suggest bestforest management practices in ways that can best protectthese values [7]

Ngumburuni Forest Reserve is one of the importantbiodiversity hotspots in Tanzania [8] that are surroundedby local communities whose livelihoods depend mostly onthe forest resources [9] Following the current poor forestmanagement practices in the Ngumburuni Forest Reserve(NFR) its natural resource-base is likely to become moreseverely deteriorated in the near future [10] Earlier studieshave reported various interactions between the surrounding

2 International Journal of Forestry Research

communities and forest resources in Ngumburuni [8 11 12]but detailed scientific information that indicates how thisdependence affects the tree biodiversity is still lacking Thisstudy was therefore conducted to fill in this information gapIt is anticipated that answers from this studywill be importantfor developing sustainable management plans for NFR andother forest ecosystems within the coastal area of Tanzania

2 Materials and Methods

21 Study Area Ngumburuni Forest Reserve is located inRufiji District Coast Region Tanzania between 7∘ 381015840ndash7∘481015840 S and 38∘ 521015840ndash39∘ 61015840 E (Figure 1) With elevation of 200mabove the mean sea level the forest covers about 10000 haAverage annual rainfall varies from 900mm to 1400mmwith significant daily monthly and annual fluctuationstemperatures range between 24 and 31∘C with the averageof 26∘C [11] The main economic activities of the adjacentcommunities are agriculture and various forest dependentactivities The vegetation of the study area is characterizedby four easily distinguished ecological units which includethe coastal Miombo woodland and riverine forests [11]composed of several tree species with high level of plantspecies endemism [13] Similarly several species of endemicmammals and birds are found in the coastal forests [11]

22 Data Collection Ecological forest inventory and socioe-conomic surveys were conducted to collect data for thisstudy Ecological data for example vegetation structurewere collected using the latest Landsat TM Satellite imagewhich permitted the identification and mapping of majorecological features and other land uses The subscenes ofthe study area were subjected to visual interpretation andidentified land coveruse changes were digitized on screenusing the ArcView software Visual image interpretationwas complemented with ground truthing survey while theGPS equipment was used to mark the positions of forestboundaries and other useful features like trail roads andmost disturbed forest areas Based on the conservation statusof the forest we grouped the vegetation covers into twomajor categories namely disturbed and undisturbed strataThe disturbed stratum involved all areas of the forest whereanthropogenic activities were dominant while undisturbedstratum involved the rest of forest areas that were notdegraded

The forest inventory exercise was conducted to establishsample plots where we proceeded with developing transectsand laying out plots on the map of the forest To coverthe whole woodland area and variation between vegetationcovers we adopted the systematic sampling design accordingto [14] who recommended that systematic sampling designincreases the chances of including all vegetation types in thewoodland Because of time constraints and limited resourceswe established only two transects one within the disturbedarea close to Mkupuka and Mangwi villages and the otherone within undisturbed stratum close to Muyuyu villageSample plots were calculated based on the following formula119899 = 119879

2

sdot CV21198902 where 119879 is 119905-value at given probability

level and degree of freedom (taken as 2) CV is coefficientof variation and 119890 is degree of error The CV of 05 wasadopted since this forest has a similar condition to thatof Miombo woodland [15] Similarly the sampling error of015 was considered sufficient since the level of precision iswithin acceptable limits of natural forests According to [15]sampling intensity within a range of 05 to 07 for tropicalnatural forest inventories is recommended Therefore thenumber of sample plots (119899) was = 4 times 02500225 = 44 Anequal number of plots (ie 22 replications) were distributedin each transect at an interval of 50m We used circularshaped sample plots because they are easy to use and alsoreduce edge effects and counting errors [16] Each sample plotwas subdivided into three concentric subplots of 2m 5m10m and 15m radii whereby the following information werecollected

(a) Within the inner 2m radius number and names of allregenerant species were recorded

(b) Within the inner 5m radius all trees and shrubs withDBH ge 4 cm their local and botanical names andfrequencies of occurrence were recorded

(c) Within the inner 10m radius all trees and shrubswithDBH ge 10 cm their local and botanical names andfrequencies of occurrence were recorded

(d) Within 15m radius all trees and shrubs with DBH ge20 cm their local and botanical names and frequen-cies of occurrence were recorded

Other useful information about the plots that were recordedincluded date of measurement Geographical PositioningSystem (GPS) readings and indicators for anthropogenicdisturbances

The socioeconomic survey was done in the three ran-domly selected villages close to the forest namely MangwiMuyuyu and Mkupuka The work started with the recon-naissance and Participatory Rural Appraisal (PRA) in orderto get an overview of the study area and modify the studyquestions Systematic sampling was adopted in selectingthe respondents so as to include people of different agegender and wealth categories as reflected from PRA resultsThe second phase involved the administration of structuredquestionnaires so that 30 households from each of thesample villages were interviewed using a sampling intensityof 5 Key informants such as village leaders extensionstaff NGOs various community groups (ie environmentalcommittees the youth women etc) and district officialswere also interviewed using checklists of probe questions tosupplement information collected from the households

Secondary information including village demographicdata and previous survey reports was collected from villageregistries the libraries of district and various research insti-tutions

23 Data Analysis The GIS data was analysed by the use ofArc View 13 and ERDAS Imagine Software Version 831programs to understand themajor forest vegetation types andother land uses

International Journal of Forestry Research 3

Ruhoi River

Mkupuka

Mangwi

N

Tanzania

Reserve boundaryVillage

Sample plotRiver

Umwe (km)0 05 1

Muyuyu

23 24 25 26 28 30 32 34 3637 40 42 4427 29 31 33 35 3839 41 43

12

34

56

78

910

11

1213

1415

16

1718

1920 22

21

Figure 1 Map of the study area

We determined species importance value index (IVI)from data on basal area frequency and density of treespecies in both major strata According to [17] basal areameasures the area occupied by the stems of trees whilespecies frequency and density are important to measuredistribution of species within the population Computationof species dominance was done using the following formula

ID = sum(119899119894

119873

)

2

(1)

where ID is Index of Dominance 119899119894is important value index

of each individual species and 119873 is total Importance valueindex of all species The greater the value of ID the strongerthe community is dominated by one or few species only

The status of species diversity and richness data wereanalyzed by use of Shannon diversity index as summarizedin the following formula

119867 = minus

119904

sum

119894=1

119901119894 log119901119894 (2)

where 1198671015840 is the Shannon-Wiener biodiversity index log119890

is the natural log of 119901119894 119904 is total number of species inthe community and 119901119894 is proportion of 119904 made up of the119894th species The larger the value of ldquo119867rdquo the greater thediversity and vice versa According to [17] diversity indicesprovide more information about community compositionthan simply species richness by taking into account relativeabundance of different species The regeneration potential ofNFR was analyzed from tree species with DBH less than 5 cm


Table 1 Age-sex distribution of respondents (119899 = 90)

Age range Female Male Total 0ndash19 5 (714) 2 (286) 7 820ndash40 25 (352) 46 (648) 71 7940ndash60+ 8 (667) 4 (333) 12 13Own survey 2007

Table 2 Relationship between size of farms and yield of cassava

Land holdings(Acre)

Number of bags of cassava Totallt50 () 50ndash100 () lt100 ()

Up to 5 5 (26) 10 (526) 4 (21) 195 to 10 8 (296) 14 (518) 5 (185) 2710 to 15 6 (286) 7 (333) 8 (3809) 21Above 15 5 (217) 8 (3478) 10 (435) 23Total 24 (267) 39 (433) 27 (30) 90 (100)Source own survey 2007Chi-square = 55 and NS DF = 6 at 119875 = 005

measured in the 2 meters radius of the sample plots in bothstrata

Socioeconomic data were analyzed by a combination ofqualitative and quantitative methods Qualitative data wereanalyzed using content analysis [18] whereas quantitativedata were analyzed with the aid of Statistical Package forSocial Sciences (SPSS) version 16 and Excel Spread Sheet(ESS) 2003

3 Results and Discussion

31 Social-Economic Factors Affecting the Biodiversity of NFRResponse from key informants revealed that economic fac-tors were most significant to degradation of NFR Otherimportant factors were demographic and institutional relat-ing issues Economic activities mostly reported by commu-nities were logging (30) charcoaling (21) and shiftingcultivation (20) as shown in Figure 2

The proportion of males (648) was almost twice thatof females within the middle aged group (Table 1) Being atthis active age the majority of men around NFR fit well withharsh and stressful forest activities such as felling down treescarrying logs and preparing charcoal pits Similarly it hasbeen observed that males can easily dare to travel far fromhome for some days looking for bigger-sized trees or highquality timber [9] In line with this finding [10] commentedthat women are less involved in forest activities becauseof being responsible of several domestic duties includinglooking after children and cooking for the families

Further to this it was found that most villagersrsquo farmswere not productive enough to sustain their food requirementandor selling the excess as a means of generating householdincome (Table 2) Cassava is the main food crop grown atRufiji District followed by maize and cowpea [9] Numberof reasons were mentioned by farmers with regard to lowagricultural productivity around NFR For example 68of household respondents revealed that they have not been

charcoaling21

Logging30Cultivation

20

Grazing5

Collecting medicinal

plants6

Hunting5

Employed in formal sectors

5

Other small business

8

Figure 2 Major income sources of communities around Ngumbu-runi Forest Reserve

visited by agriculture extension officer or being invitedto workshops for the past three years According to [3]most smallholder farmers in developing countries lack basicagricultural skills important for sustaining food productionor adapting environmental challenges brought by climaticchanges Encroaching and clearing part of the forest forestablishing new farms were reported by District ForestOfficer as the strategy used by villagers to acquire fertile landthat will substitute low yield realized in their own traditionalfarms Worse enough these plots are abandoned after beingused for a short time A similar practice has been reported inZambia whereby a shifting cultivation practice locally knownas Chitemene involves clearing and burning part of the forestfor crop production [3]

NFR has for many years been reported to be oneof the important timber extraction hotspots in SouthernTanzania [12] following increasing demand of hard woodin international trade [19] Local communities around NFRon the other hand also prefer some forest trees species forconstruction and firewood Seventy eight (78) of the house-hold respondents indicated that an average-sized rural housewould roughly need between 200 to 300 poles which last upto five years This short life span implies that communitieswill need to access the forest more frequently looking forpoles among the shrub species and regenerating stems of treespecies [11]

32 Tree Composition and Species Abundance We recordeda total of 63 species from both strata within NFR wherebyHyphaene compressa was the most abundant followed byVitex doniana Euclea divinorum Syzygium cuminii Acacisnigrescens Grewia trichocarpa Albizia versicolor and Lanneaschweinfurthii It was also noted that over 63 of the specieswere in degraded forest while only 37 were found in closedforest (Table 1) This indicates that there is more speciesdiversity in disturbed forest compared to undisturbed forest


Table 3 Biodiversity characteristics of trees and shrubs in both disturbed and undisturbed forests

Parameter Undisturbed forest Disturbed forest Computed 119865Species richness () 37 63 713lowast

Density of regenerants () 60 40 893lowast

Stem per ha 554 390 123lowast

Shannon index (119867) 2 37 4246lowast

Index of dominance 009 0026 977lowast

Source own survey 2007119865(142) = 407 119875 lt 005

area most likely caused by ongoing disturbances Accordingto [17] opening forest canopy creates wider gaps whichenhance emergence of suppressed understory species

Data on tree density and basal area also confirm ongo-ing disturbances within NFR It was noted that there was334 decline in density of all large trees useful for timberand charcoal production in disturbed area As respondedby key informant engagement of the local community tocommercial logging and charcoal production has increasedtremendously since 2000 when government improved roadinfrastructureswithinRufiji districtMassive tons of logs havebeen exported to South Asia and European countries fromRufiji District through Dar es Salaam Port which is about120 km from the forest [12]This finding is comparable to thatobserved by [13] whereby selective logging in Cambodia alsoreduced the mean basal area and tree densities of the forestmuch in logged forest compared to unlogged one

33 Species Diversity and Dominance The results on thespecies diversity and species dominance are presented inTable 3 which confirm that the status of forest biodiversitybetween the two strata is differing significantly It was notedthat there is less tree species diversity in closed forest stratumcompared to disturbed stratum Probably this is influencedby pioneer species characterizing the underground seed bankthan what is being indicated by the standing vegetation of thetwo strata The lower index of dominance in the disturbedforest further confirms imbalance in species distributionwithin the disturbed stratum as a result of the differentialspecies preferences in the harvesting Most loggers prefertrees with large diameter and straight shape Species likeMilia excels and Pterocarpus angolensis have been reportedto be endangered in most Miombo woodlands in Tanzania[20] observed that P angolensis could nearly be completelydepleted in the foreseeable future in Msaginia Forest Reservein western Tanzania A similar observation was made by[21] in Swagaswaga Game Reserve in Kondoa Tanzaniawhere selective cutting has exhausted valuable timber speciesleading to a shift towards cutting smaller diameter trees andless preferable ones like Brachystegia spiciformis Howeverthe values of tree diversity indices indicate that both stratahave high value of species richness at NFR According to[22] Shannonrsquos index of value greater than 2 is assigned asmedium to high diversity The higher value of diversity indisturbed stratum implies that disturbances in NFR openup the forest canopy thereby creating favourable conditionsfor the emergency of new species or regrowth of suppressed

Others18 Pteleopsis

myrtifolia4

Hymenocardia ulmoides

4

Annona senegalensis

5Manilkara

sansibarensis5

Markhamia obtusifolia

12

Vitex doniana34

Hyphaene compressa

18

Figure 3 Percentage distribution of regenerants in closed foreststratum

species [23] In degraded stratum new fifteen emergentspecies had been observed which probably contributed tohigher plant diversity The closed forest stratum of NFRhowever still harbors important biodiversity and constitutesa unique habitat for rare or threatened species Duringthe Songas pipeline survey Aframomum orientale a plantendemic to Rufiji and Mkuranga districts and two orchidsMicrocoelia exilis and Microcoelia megalorrhiza were found[24]

The values of index of dominance from this study(Table 3) indicated that few species in the closed stratumdominated others These include the following tree speciesHyphaene compressa Euclea divinorum Syzygium cuminiiAntidesma venosum and Albizia versicolor The values ofindices of dominance in degraded strata compare well withvalues of 0005 and 004 in the Usambara and Ulugurusrespectively [13]These forests have been subjected to humandisturbances such as logging and other encroachments inthe past According to [25] high levels of extraction oflive wood tend to affect forest composition and structureleading to alteration in the forest ecosystem functions andimminent succession collapse Species which maintain majorfunctions of the ecosystems are referred to as keystonespecies Removing even a few of these species tends to affectthe functioning of ecosystems [26]


Others15

Dombeya rotundifolia6

Albizia versicolour6

Grewia trichocarpa7Senna sp

7Hymenaea verrucosa

9

Markhamia obtusifolia10

Hyphaene compressa

12

Vitex doniana 28

Figure 4 Percentage distribution of regenerants in open foreststratum

34 Distribution of Regenerants The results on the regener-ation status of the trees in the forest reserve are presentedin Table 3 and Figures 3 and 4 It was noted that theregeneration in the undisturbed forest stratum was 60 ofthe total indicating that the degradation of NgumburuniForest Reserve is likely to escalate with the continued forestencroachmentThis could result in impairment in the overallregeneration potential of the reserve and further impactingon the fast degrading tree species diversity It is likely thatthe opened canopy in NFR allows much more sunlight toreach forest base and break the seed dormancies andorpromote fast growth of the young trees It was observed thatin both forest strata the most abundant tree species (ie Vdoniana H compressa andM obtusifolia) are proportionallydominating the regeneration populations

The higher regeneration status of tree species within theclosed stratum is different from that found by [27] whonoted that the regeneration of tree species was decreasingfrom the main road towards the centre of the forest reserveThe situation at Ngumburuni may be caused by the morefrequently occurring fires which cause deaths to some ofthe seeds in the soil [15] had the same observation inHerena Forest Reserve in Ethiopia whereby the proportionof germinating seeds from unburned soil sample was higherthan in the burnedone It can be realized therefore thatmanytrees at NFR are germinating by means of seeds which aresusceptible to fires

4 Conclusion

Humandisturbance had a significant effect on forest structureand composition in Ngumburuni Forest Reserve leading tolowered densities of useful plants especially important timbertrees Fire was observed to be the central part of severaldisturbances reported to take place in Ngumburuni such asshifting cultivation charcoaling and logging It was furthernoted that poor economic status among many villagers wasclosely connected to accessibility to the forest Despite the factthat NFR still holds an important proportion of tree species

richness there is a need to prevent further human distur-bances within the forest so that it can sustain its ecologicalfunctioning Strict law enforcement on exploitation of forestresources community education and promotion of alter-native income generating activities should be encouragedSimilarly restoration of the ecosystem through reforestationin most degraded areas of the forest should also be givenimmediate attention by forest management authorities

References

[1] C H Cannon D R Peart and M Leighton ldquoTree speciesdiversity in commercially logged Bornean rainforestrdquo Sciencevol 281 no 5381 pp 1366ndash1368 1998

[2] F E Putz K H Redif and J G Robinson BiodiversityConservation in the Context of Tropical Forest ManagementTheWorld Bank Environmental DepartmentWashington DCUSA 2000

[3] C Shackleton and S Shackleton ldquoThe importance of non-timber forest products in rural livelihood security and as safetynets a review of evidence from South Africardquo South AfricanJournal of Science vol 100 no 11-12 pp 658ndash664 2004

[4] J S Denslow ldquoDisturbance and diversity in tropical rain foreststhe density effectrdquo Ecological Applications vol 5 no 4 pp 962ndash968 1995

[5] K Eichhorn ldquoThe plant community of Sungai Wain EastKalimantan Indonesia phytogeographical status and localvariationrdquo Blumea Supplement vol 18 pp 15ndash35 2006

[6] M A Pinard M G Barker and J Tay ldquoSoil disturbanceand post-logging forest recovery on bulldozer paths in SabahMalaysiardquo Forest Ecology and Management vol 130 no 1ndash3 pp213ndash225 2000

[7] S A Pickett ldquoDrivers and dynamics of change in biodiversityrdquoin Global Biodiversity Assessment V H Heywood and RT Watson Eds pp 311ndash318 United Nations EnvironmentProgramme Cambridge UK 1995

[8] J Kimaro and L Lulandala ldquoContribution of non-timber forestproducts to poverty alleviation and forest conservation in RufijiDistrictmdashTanzaniardquo Journal of Livestock Research For RuralDevelopment Livestock Research For Rural Development vol 25no 5 2013

[9] REMP Report on Strategy for Assessment of the Woody Vegeta-tion of the Rufiji District REMP Rufiji Tanzania 2003

[10] B K Kaale H K Ramadhani B T Kimaryo R S Maro andH Abdi Participatory Forest Resource Assessment Misitu YetuProject CARE Tanzania Dar es Salaam Tanzania 2002

[11] N D Burgess and G P Clarke Coastal Forest of Eastern AfricaIUCN Gland Switzerland 2000

[12] S A H Milledge and B K Kaale Bridging the GapmdashLinkingTimber Trade with Infrastructural Development in SouthernTanzania Baseline Data before Completion of theMkapa BridgeTRAFFICEastSouthernAfrica Dar es Salaam Tanzania 2005

[13] P K T Munishi and T H Shear ldquoRainfall interception andpartitioning in afromontane rain forests of the Eastern ArcMountains Tanzania implications for water conservationrdquoJournal of Tropical Forest Science vol 17 no 3 pp 355ndash3652005

[14] S M Philip Measuring Trees and Forests CAB InternationalWallingford UK 2nd edition 1994


[15] R E Malimbwi ldquoAn Inventory Report of the Principle TimberResources of the Miombo and RiverineWoodlands and Forestsof Rufiji Districtrdquo Tech Rep 12 REMP Utete Tanzania 2000

[16] C J Krebs Ecological Methodology Hamper Collins New YorkNY USA 1989

[17] R A Giliba E K Boon C J Kayombo E B Musamba AM Kashindye and P F Shayo ldquoSpecies composition richnessand diversity in Miombo Woodland of Bereku Forest ReserveTanzaniardquo Journal of Biodiversity vol 2 no 1 pp 1ndash7 2011

[18] G C Kajembe Indiginous Management Systems as a Basic forCommunity Forestry in Tanzania A Case Study of DodomaUrban and Lushoto Districts Wageningen Agricultural Univer-sity Wageningen The Netherlands 1994

[19] LLC ldquoIllegalrdquo Loging and Global Wood Markerts Seneca CreekAssociates LLC andWood Resources International LLC 2004

[20] M W Schwartz T M Caro and T Banda-Sakala ldquoAssessingthe sustainability of harvest of Pterocarpus angolensis in RukwaRegion Tanzaniardquo Forest Ecology andManagement vol 170 no1ndash3 pp 259ndash269 2002

[21] N F Madulu Population Dynamics and Sustainable Conserva-tion of Protected Areas in Tanzania the Case of SwagaswagaGame Reserve in Kondoa District Department of Earth Sci-ences Programme for Applied Environmental Impact Assess-ment Villavagen Uppsala Sweden 2001

[22] G M Barbour H J Burk and W D Pitts Terrestrial PlantEcology The BenjaminCummings Publishing Redwood CityCalif USA 1987

[23] R S Ambasht A Survey of the Avifauna of Chome ForestReserve South Pare Mountains North-East Tanzania EastAfrican Cross-Border Biodiversty Project Arusha Tanzania2001

[24] Songas ldquoSongo songo gas to electricity project environmentalstudiesrdquo Final Report SONGASDar es Salaam Tanzania 2003

[25] J Obiri M Lawes and M Mukolwe ldquoThe dynamics and sus-tainable use of high-value tree species of the coastal Pondolandforests of the Eastern Cape Province South Africardquo ForestEcology and Management vol 166 no 1ndash3 pp 131ndash148 2002

[26] T Jackson K Begg and S Parkinson Flexibility in ClimatePolicymdashMaking the Kyoto Mechanisim Work Earthscan Lon-don UK 2001

[27] G Tesfaye D Teketay Y Assefa and M Fetene ldquoThe impact offire on the soil seed bank and regeneration of Harenna Forestsoutheastern Ethiopiardquo Mountain Research and Developmentvol 24 no 4 pp 354ndash361 2004

Submit your manuscripts athttpwwwhindawicom

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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ClimatologyJournal of


communities and forest resources in Ngumburuni [8 11 12]but detailed scientific information that indicates how thisdependence affects the tree biodiversity is still lacking Thisstudy was therefore conducted to fill in this information gapIt is anticipated that answers from this studywill be importantfor developing sustainable management plans for NFR andother forest ecosystems within the coastal area of Tanzania

2 Materials and Methods

21 Study Area Ngumburuni Forest Reserve is located inRufiji District Coast Region Tanzania between 7∘ 381015840ndash7∘481015840 S and 38∘ 521015840ndash39∘ 61015840 E (Figure 1) With elevation of 200mabove the mean sea level the forest covers about 10000 haAverage annual rainfall varies from 900mm to 1400mmwith significant daily monthly and annual fluctuationstemperatures range between 24 and 31∘C with the averageof 26∘C [11] The main economic activities of the adjacentcommunities are agriculture and various forest dependentactivities The vegetation of the study area is characterizedby four easily distinguished ecological units which includethe coastal Miombo woodland and riverine forests [11]composed of several tree species with high level of plantspecies endemism [13] Similarly several species of endemicmammals and birds are found in the coastal forests [11]

22 Data Collection Ecological forest inventory and socioe-conomic surveys were conducted to collect data for thisstudy Ecological data for example vegetation structurewere collected using the latest Landsat TM Satellite imagewhich permitted the identification and mapping of majorecological features and other land uses The subscenes ofthe study area were subjected to visual interpretation andidentified land coveruse changes were digitized on screenusing the ArcView software Visual image interpretationwas complemented with ground truthing survey while theGPS equipment was used to mark the positions of forestboundaries and other useful features like trail roads andmost disturbed forest areas Based on the conservation statusof the forest we grouped the vegetation covers into twomajor categories namely disturbed and undisturbed strataThe disturbed stratum involved all areas of the forest whereanthropogenic activities were dominant while undisturbedstratum involved the rest of forest areas that were notdegraded

The forest inventory exercise was conducted to establishsample plots where we proceeded with developing transectsand laying out plots on the map of the forest To coverthe whole woodland area and variation between vegetationcovers we adopted the systematic sampling design accordingto [14] who recommended that systematic sampling designincreases the chances of including all vegetation types in thewoodland Because of time constraints and limited resourceswe established only two transects one within the disturbedarea close to Mkupuka and Mangwi villages and the otherone within undisturbed stratum close to Muyuyu villageSample plots were calculated based on the following formula119899 = 119879

2

sdot CV21198902 where 119879 is 119905-value at given probability

level and degree of freedom (taken as 2) CV is coefficientof variation and 119890 is degree of error The CV of 05 wasadopted since this forest has a similar condition to thatof Miombo woodland [15] Similarly the sampling error of015 was considered sufficient since the level of precision iswithin acceptable limits of natural forests According to [15]sampling intensity within a range of 05 to 07 for tropicalnatural forest inventories is recommended Therefore thenumber of sample plots (119899) was = 4 times 02500225 = 44 Anequal number of plots (ie 22 replications) were distributedin each transect at an interval of 50m We used circularshaped sample plots because they are easy to use and alsoreduce edge effects and counting errors [16] Each sample plotwas subdivided into three concentric subplots of 2m 5m10m and 15m radii whereby the following information werecollected

(a) Within the inner 2m radius number and names of allregenerant species were recorded

(b) Within the inner 5m radius all trees and shrubs withDBH ge 4 cm their local and botanical names andfrequencies of occurrence were recorded

(c) Within the inner 10m radius all trees and shrubswithDBH ge 10 cm their local and botanical names andfrequencies of occurrence were recorded

(d) Within 15m radius all trees and shrubs with DBH ge20 cm their local and botanical names and frequen-cies of occurrence were recorded

Other useful information about the plots that were recordedincluded date of measurement Geographical PositioningSystem (GPS) readings and indicators for anthropogenicdisturbances

The socioeconomic survey was done in the three ran-domly selected villages close to the forest namely MangwiMuyuyu and Mkupuka The work started with the recon-naissance and Participatory Rural Appraisal (PRA) in orderto get an overview of the study area and modify the studyquestions Systematic sampling was adopted in selectingthe respondents so as to include people of different agegender and wealth categories as reflected from PRA resultsThe second phase involved the administration of structuredquestionnaires so that 30 households from each of thesample villages were interviewed using a sampling intensityof 5 Key informants such as village leaders extensionstaff NGOs various community groups (ie environmentalcommittees the youth women etc) and district officialswere also interviewed using checklists of probe questions tosupplement information collected from the households

Secondary information including village demographicdata and previous survey reports was collected from villageregistries the libraries of district and various research insti-tutions

23 Data Analysis The GIS data was analysed by the use ofArc View 13 and ERDAS Imagine Software Version 831programs to understand themajor forest vegetation types andother land uses


Ruhoi River

Mkupuka

Mangwi

N

Tanzania


Sample plotRiver

Umwe (km)0 05 1

Muyuyu

23 24 25 26 28 30 32 34 3637 40 42 4427 29 31 33 35 3839 41 43

12

34

56

78

910

11

1213

1415

16

1718

1920 22

21



ID = sum(119899119894

119873

)

2

(1)




119867 = minus

119904

sum

119894=1

119901119894 log119901119894 (2)







Land holdings(Acre)









charcoaling21


20

Grazing5


plants6

Hunting5


5


8
















Others18 Pteleopsis

myrtifolia4


4

Annona senegalensis

5Manilkara

sansibarensis5


12

Vitex doniana34

Hyphaene compressa

18





Others15




7Hymenaea verrucosa

9


Hyphaene compressa

12

Vitex doniana 28




4 Conclusion



References

































Journal of












Volume 2014

Advances in









Geophysics















Ruhoi River

Mkupuka

Mangwi

N

Tanzania


Sample plotRiver

Umwe (km)0 05 1

Muyuyu

23 24 25 26 28 30 32 34 3637 40 42 4427 29 31 33 35 3839 41 43

12

34

56

78

910

11

1213

1415

16

1718

1920 22

21



ID = sum(119899119894

119873

)

2

(1)




119867 = minus

119904

sum

119894=1

119901119894 log119901119894 (2)







Land holdings(Acre)









charcoaling21


20

Grazing5


plants6

Hunting5


5


8
















Others18 Pteleopsis

myrtifolia4


4

Annona senegalensis

5Manilkara

sansibarensis5


12

Vitex doniana34

Hyphaene compressa

18





Others15




7Hymenaea verrucosa

9


Hyphaene compressa

12

Vitex doniana 28




4 Conclusion



References

































Journal of












Volume 2014

Advances in









Geophysics


















Land holdings(Acre)









charcoaling21


20

Grazing5


plants6

Hunting5


5


8
















Others18 Pteleopsis

myrtifolia4


4

Annona senegalensis

5Manilkara

sansibarensis5


12

Vitex doniana34

Hyphaene compressa

18





Others15




7Hymenaea verrucosa

9


Hyphaene compressa

12

Vitex doniana 28




4 Conclusion



References

































Journal of












Volume 2014

Advances in









Geophysics

























Others18 Pteleopsis

myrtifolia4


4

Annona senegalensis

5Manilkara

sansibarensis5


12

Vitex doniana34

Hyphaene compressa

18





Others15




7Hymenaea verrucosa

9


Hyphaene compressa

12

Vitex doniana 28




4 Conclusion



References

































Journal of












Volume 2014

Advances in









Geophysics















Others15




7Hymenaea verrucosa

9


Hyphaene compressa

12

Vitex doniana 28




4 Conclusion



References

































Journal of












Volume 2014

Advances in









Geophysics
































Journal of












Volume 2014

Advances in









Geophysics


















Journal of












Volume 2014

Advances in









Geophysics














Documents

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