Browsing by Author "Treydte, Anna"

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Balancing African Elephant Conservation with Human Well-Being in Rombo Area, Tanzania
(Hindawi Advances in Ecology, 2017-05-31) Mmbaga, Naza; Munishi, Linus; Treydte, Anna
The critical assessment of the nature and extent of human-elephant conflict (HEC) and its impact on conservation efforts are essential if we are to meet the challenges related to extinction of local population, as well as loss biodiversity. Conservationists need detailed information on HEC in areas where these challenges prevail to improve intervention in the face of limited funds/resources. We assessed the status of HEC at Rombo area over the last six years. Data based on household surveys, focus group discussions, spatiotemporal analysis of site observations, and reported incidents of damage within the last six years were mapped. Out of all HEC cases analyzed, the most were crop damage which took place at night and the damage was severe between May and July, when cereal crops were mature. In upland areas of Rombo, HEC hotspots were observed inside the protected forest plantation where local people cultivated their annual crops. Cold spots concentrated in upland areas outside the protected forest plantation dominated by settlement and agroforestry less preferred by elephants. In lowland areas,HEChotspotswere observed in village lands close to the PAs, within settlement and farmland dominated by seasonal crops. This suggests that HEC management efforts such as establishment of buffer zones should be directed around the areas adjacent to PAs and prevention should focus on cultivation of the alternative crops and farming systems that are less preferred by elephants. Our study highlights the importance of using a combination of data collection techniques to pinpoint fine-scale HEC hotspots in a highly conflict-prone location of Tanzania.
Balancing Bees and Livestock: Pastoralist Knowledge, Perceptions and Implications for Pollinator Conservation in Rangelands, Northern Tanzania
(SAGE journal, 2021-01-01) Mpondo, Faith; Ndakidemi, Patrick; Treydte, Anna
Insect pollinators provide numerous ecosystem services that support other living organisms. While pollinators play a large role in cropping systems, little is known about their presence and function in rangeland ecosystems, which have recently become fragmented and overexploited at an extraordinary rate. We assessed local Maasai knowledge on insect pollinators and how pollinators affect livelihood diversification in Simanjiro rangelands, Tanzania. Through questionnaires, key informant interviews, focus group discussions, and field observations, we found varied insect knowledge among Maasai herders. Lasioglossum of sub genus Ipomalictus and Syriphidae were the least commonly recognized pollinators as only 24%, and 7% of participants could identify them, respectively. Responses varied significantly between men and women (F ¼ 7.397, p ¼.007). Commiphora africana, Acacia mellifera and Albizia anthelmintica were noted as most important bee forage plants while observations showed Aspilia mossambicensis, Justicia debile and Acacia tortilis. Most (77%) of Maasai herders showed limited ability to link pollinators and rangeland wellbeing. Beekeeping contributed to livelihood diversification for 61% of respondents, with women participating more frequently than men (v2 ¼ 46.962, p ¼.0001). Beekeeping was positively influenced by education level (R ¼ .421, p <.0001) and occupation (R ¼ .194, p ¼.009). Pollinator declines were attributed to climate change (47%), agriculture (37%), and habitat destruction (8%). We conclude that Maasai have limited knowledge of common pollinator groups and their roles. Community outreach and training should bridge the knowledge gap in pastoralist communities to fully realize pollinator benefits and highlight the importance of rangeland health.
Bio-herbicide potential of naturalised Desmodium uncinatum crude leaf extract against the invasive plant species Parthenium hysterophorus
(Springer Nature Switzerland AG, 2019-08-16) Ojija, Frederick; Arnold, Sarah; Treydte, Anna
The exotic plant Parthenium hysterophorus is rapidly invading ecosystems in sub-Saharan Africa, with negative effects on the environment, economy and human and animal health. With the exception of some synthetic herbicides, none of the available management methods have been effective against P. hysterophorus, and carry risks to the environment. Therefore, additional management methods must be explored for an effective integrated approach. Despite the fact that bio-herbicides are considered cost-effective and eco-friendly in mitigating biological invasions, little work has been done to utilize them for controlling P. hysterophorus. We investigated allelopathic effects and, thus, bio-herbicide potential of naturalised Desmodium uncinatum leaf (DuL) crude extract in various concentrations to control P. hysterophorus. Our results revealed that DuL crude extract can suppress P. hysterophorus, particularly at higher concentrations. The 75% and 100% DuL crude extract concentrations reduced the total leaf chlorophyll content by 26% and 22% in pots and plots, respectively. Further, these higher concentrations inhibited P. hysterophorus seed germination by 73% in petri dishes, 60% in pots, and 57% in plots, and negatively interfered with seedling growth vigour. Seedling stem heights under 75% and 100% DuL concentrations in pot and plot experiments was about 30% and 36% shorter than those sprayed with lower concentrations (< 70%) and the control, respectively. We show that naturalised plants with allelochemicals can be used as a management tool for controlling P. hysterophorus infestations in sub-Saharan Africa, particularly in Tanzania, and this method should become part of an integrated control toolkit being deployed in a community-based approach.
Bionomics of the African Apefly (Spalgis lemolea) as A Potential Natural Enemy of the Papaya Mealybug (Paracoccus marginatus) in Tanzania
(MDPI, 2020-04-14) Nasari, Sayuni; Treydte, Anna; Ndakidemi, Patrick; Mbega, Ernest
The African apefly (Spalgis lemolea Druce) is a potential natural enemy of the papaya mealybug (Paracoccus marginatus Williams and Granara de Willink). We studied the life history of apeflies in the laboratory at a temperature of 25–27 °C and a relative humidity of 55%–65% under a 12 h photoperiod condition. The papaya mealybugs and apefly larvae were collected from papaya plants in Tengeru, Arusha, Tanzania. The papaya mealybugs were introduced and allowed to multiply on potted sprouting potato plants in screened cages. In order to study the life cycle and predation of apeflies, an apefly egg was placed on an open screen-covered petri dish containing a moist blotter paper and observed for larva emergence. After the apefly larva emergence, a mixture of mealybug eggs (up to 1500), nymphs (200–250) and adults (100–150) was introduced in the petri dish each day and the consumption rate by the apefly larvae was quantified until the larvae reached pupal stage. Then, the apefly adults were collected and put into cages 30 cm × 30 cm × 30 cm containing cotton wool soaked in water, for observation of pre-mating, mating, egg-laying and life span. Results indicate that the apefly completed its life cycle in 23 days. The mean development period of the eggs was four days and the development period for the larva, pre-pupa, and pupa was nine, one and ten days respectively. The adult apefly emerged after 9 days of the pupa stage with mean body lengths of 10.1 ± 0.4 mm and 11.0 ± 0.8 mm for the males and females, respectively. The female laid an average of 68 eggs in groups of two to seven at different sites after 4–5 days of emergence. In this study one apefly larva was capable of consuming about 1983 ± 117, 123 ± 6 and 80 ± 9 papaya mealybug eggs, nymphs and adults respectively during larval stage. These results reveal the predatory potential of the apefly in suppressing the population of papaya mealybugs under field conditions.
Can Cynodon dactylon Suppress the Growth and Development of the Invasive Weeds Tagetes minuta and Gutenbergia cordifolia?
(MDPI, 2019-12-06) Ngondya, Issakwisa; Treydte, Anna; Ndakidemi, Patrick; Munishi, Linus
Approaches to managing invasive plants is challenging, particularly in protected areas where conventional methods, such as chemical herbicide applications are limited. We studied the effects of varying densities of Cynodon dactylon on the growth and development of the invasive weeds Tagetes minuta and Gutenbergia cordifolia in northern Tanzania. We conducted pot and field plot experiments following a completely randomized block design that was replicated three times. Increasing densities of C. dactylon significantly reduced growth, leaf total chlorophyll, biomass and significantly increased leaf anthocyanin of both T. minuta and G. cordifolia invasives. Our results further showed that the critical density of C. dactylon to suppress the two invasive species is ≥ 8 plants/m2. We suggest that C. dactylon can successfully be used as an alternative eco-friendly and sustainable approach for managing invasive weeds, such as T. minuta and G. cordifolia. This management technique can additionally improve forage production and biomass for wild and domestic herbivores in the affected areas.
Characterization of bird, reptile, and insect community diversity in constructed wetlands and waste stabilization ponds across Tanzania
(Elsevier, 2023-11) Msaki, Gerubin; Njau, Karoli; Treydte, Anna; Lyimo, Thomas
Wastewater treatment systems, such as Constructed Wetlands (CWs) and Waste Stabilization Ponds (WSPs), have untapped biodiversity enhancement and development potential. Birds, insects, and reptiles, which are displaced by human development, might find refuge in these ecosystems. However, the lack of a detailed characterization of the biodiversity status of these wastewater treatment systems hinders their widespread adoption. Point counts, direct observations, and camera traps were used to assess bird diversity across five CWs and three WSPs in Tanzania in 2021. For insects and reptiles, pitfall and pan traps were laid along established transects, in addition, direct observations and fishnets were also used to assess the reptiles dwelling within the WSPs. Abundance, Shannon index, Simpson index, Margalef index, and evenness index were the diversity parameters used to analyze the diversity of birds, insects, and reptiles. Our results show that among the studied groups and between WSPs and CWs, birds had high species abundance (n = 1132), richness, Margalef index (D = 4.266), evenness (E = 0.815), Shannon diversity (H = 2.881) and Simpson index (λ =0.903). The abundance and diversity of studied groups differed significantly (P < 0.05) between WSPs and CWs. Our study also recorded four reptile species belonging to three orders. Molecular analyses confirmed that insect species belong to nine orders and 13 families, with the order Diptera dominating both CWs and WSPs, followed by Orthoptera, Hymenoptera, and Araneae. We conclude that CW and WSP wastewater treatment systems are important for hosting various populations of birds, reptiles, and insect species.
Comparison of the effects of a broad-spectrum herbicide and a bio-herbicide on insect flower visitation in the Serengeti ecosystem, Tanzania
(Elsevier, 2021-12) Mbundi, Mecklina; Ngondya, Issakwisa; Ghaui, Mark; Treydte, Anna
The functional role of insect visitors on flowering plants is crucial to both natural and agricultural ecosystems. While, few studies have addressed the impact of invasive plant species on insect visitors, even less is known about how management practices against invasive plants may affect plant-pollinator interactions. We assessed how natural versus chemical-based management against the invasive plant Gutenbergia cordifolia affected insect visitors in Mwiba area, Tanzania. We compared the number of insect visitors, diversity and richness, the number of inflorescences visited, inflorescences abundance and flower diversity across treatments of Desmodium uncinatum crude leaves extract (DUL), the chemical glyphosate (GLY), and none /control (CON). We found that more than half (55%) of the insect visitors observed were found visiting flowering plants in DUL plots, followed by CON with 26% and GLY plots with 19%. Further, DUL plots had almost twice as many inflorescences visited compared to CON and GLY plots. Inflorescence’s abundance and flower diversity were significantly higher in DUL plots compared to CON and GLY plots. Our study revealed that DUL treatment did not disrupt insect flower visitation but rather attracted more insects. We conclude that using the natural plant extract treatment is highly preferable to the chemical management of invasive plants such as G. cordifolia, as the DUL treatment maintained and even enhanced flower diversity while suppressing G. cordifolia and fostering insect visitors.
Cropping patterns along an altitudinal gradient and their implications to wildlife conservation in Rombo, Tanzania
(Elsevier B.V., 2021-08) Mmbaga, Naza; Munishi, Linus; Treydte, Anna
Ecosystem and livelihood sustainability of small-scale farmers in Eastern Africa are often challenged by climate change and unsustainable land use practices. Little is known on the small-scale temporal processes of cropping systems in relation to long-term climatic conditions. To understand the climatic influence on the cropping patterns, and its implications to wildlife/elephant conservation, our study used a combination of time-series datasets on crop and climate as well as geo-spatial layers spanning more than three decades. To validate the information analyzed from secondary data, we carried out participatory observation and interviews, whereby about 5% of village households were selected along an altitudinal gradient of Rombo area, Tanzania. We generated land use change maps using Geographical Information System (ArcGIS 10.4) and used Spearman’s correlation analysis to assess the influence of rainfall, temperature, and crop yield on the observed longitudinal changes in the crop types and other land use patterns both within and across altitudinal gradients. We found that perennial crops like coffee and banana concentrated in upper agro-ecological zones, with a clear division line above 1230 masl while seasonal crops like maize and beans were mostly cultivated in lowlands (below 1230 masl). The results further showed that coffee yields significantly declined with higher average annual minimum temperatures over the last 16 years. Within the same time period, there was a disproportionate shift from coffee to seasonal crop cultivation such as maize and beans. Elephant numbers declined by about 38%, while human settlement area increased by 28% over the last 30 years. We conclude that changes in land use and shifts in climate and cropping patterns have important implications for elephant conservation and sustainability of the ecosystem in Rombo area, Tanzania.
Demonstrative effects of crude extracts of Desmodium spp. to fight against the invasive weed species Tagetes minuta
(Elsevier, 2016) Ngondya, Issakwisa; Munishi, Linus; Treydte, Anna; Ndakidemi, Patrick
Threats on native flora and fauna by invasive plant species represent one of the main conservation and management challenges in rangelands. Methods that are both effective and ecologically safe to suppress invasives are urgently needed but have rarely been used, thus, highlighting the need to devise and test ones. In our study, we used a completely randomized design to assess the allelopathic effects of Desmodium uncinatum and Desmodium intortum leaf (DuL, DiL respectively) and root (DuR, DiR respectively) extracts on germination and seedling vigor of the invasive weed Tagetes minuta.We also assessed seedling germination, height, fresh weight and chlorophyll content after fourteen days and thirty days of treatment separately. The mean percentage germination per treatment in and across each group differed significantly (P b 0.05), with DuL having the highest suppressive effect (P = 0.003). Likewise, the mean germination per treatment was more strongly negatively correlated with treatment concentration in DuL treatments in both laboratory and screen house experiments (r = −0.48, P = 0.0003 and r = −0.91, P b 0.0001 respectively) than in DuR, DiL and DiR. Seedling height, fresh weight and chlorophyll content (Chl) differed significantly (P b 0.05) between the four treatment groups. Seedlings treated with higher concentrations were observed to be shorter, having lower fresh weights and Chl content than those treated with lower concentrations. The DuL higher concentration showed a trend of shorter seedlings with lower fresh weights and Chl content than other groups. Our findings suggest that D. uncinatum may probably be used to control invasive species, T. minuta and should be integrated into the management practices in the affected areas. Also our data suggest that a potential exists in devising an innovation that is both ecologically safe and effective by using Desmodium spp. making it possible to improve rangelands production through planting them in the areas affected by invasive species.
The effect of Helichrysum shrub encroachment on orchids in a tropical, montane grassland ecosystem, Tanzania
(CSIRO PUBLISHING, 2024-11-08) Mgimba, Christopher; Ngondya, Issakwisa; Treydte, Anna
Context Although shrub encroachment is a common phenomenon in grasslands, which often suppress co-existing herbaceous plants, little is known about how encroaching native shrubs affect endemic and threatened orchid species. Aims We assessed the effect of the native dwarf shrub Helichrysum species on orchid species in a protected mountainous grassland system in Tanzania. Methods We selected five Helichrysum shrub-dominated blocks and applied four treatments in each, i.e. no or low encroachment (<20% Helichrysum cover; ‘low cover’), high encroachment (>50% Helichrysum cover; ‘high cover’), cutting all stems of Helichrysum shrubs to ground level (‘stem cut’) and removing both stems and roots of all Helichrysum shrubs (‘uprooted’). We then compared orchid species diversity, abundance and functional traits by using a mixed linear model across treatments. Key results Orchid species diversity and abundance were significantly lower in ‘high cover’ plots than in other treatments. In ‘high cover’ plots, orchid species such as Disa robusta, Satyrium acutirostrum, and S. sphaeranthum had a significantly lower chlorophyll content than they did in ‘low cover’ plots. The ‘uprooting’ treatment showed significantly higher orchid species diversity in the second field season. Conclusion The expansion of Helichrysum shrubs adversely affected orchid abundance, diversity, and individual vigour, which in turn affected the regenerative ability of orchids. Implications We suggest that management should focus on shrub removal, because only ‘cutting’ had a beneficial effect on orchids. Shrub removal should be focused on areas of high shrub cover to promote further orchid species growth in this mountainous grassland of Tanzania.
Effect of seasonality and light levels on seed germination of the invasive tree Maesopsis eminii in Amani Nature Forest Reserve, Tanzania
(Elsevier B.V., 2019) Mwendwa, Beatus; Kilawe, Charles; Treydte, Anna
Studies on germination behavior are important tools for understanding how environmental factors affect geographic distribution and colonization of invasive plants. Particularly seedlings of invasive plant species benefit from high light intensity, as often found in disturbed areas of low canopy cover. We investigated the effect of various shade levels on seed germination and early growth of the invasive tree Maesopsis eminii at the nursery of a biodiversity hotspot, the Amani Nature Forest Reserve, Tanzania. Shade houses provided forest-like sun flecks of four categories (0%, 50%, 65% and 85% shade), representing light regimes found in tropical natural forests throughout the entire growing season. The average germination rate across the four different shade levels differed significantly during the dry season (F3,12 = 48.74, P < 0.001) but not in the wet season (F3,12 = 3.49, P = 0.051). Final germination percentage at 0% shade was 1.5 times higher compared to that under 85% shade during the wet season. In both dry and wet seasons, stem diameter, shoot height, total fresh and dry biomass significantly decreased with an increase in shade levels. During the dry season, leaf chlorophyll contents were three times higher at 85% and 65% shade than at 0% shade. Both seasonality and shade levels as well as their interactions influenced most germination parameters but not growth parameters except stem diameter. The conclude that M. eminii seed germination is fostered by light as it prefers colonizing in forest gaps, and lower light levels might act as a barrier to its invasive capacity, particularly during the dry season. Hence, management strategies of M. eminii should include the provision of unfavorable light regimes and take seasonality into account.
Effectiveness of Zygogramma bicolorata as a biocontrol agent against Parthenium hysterophorus in Arusha, Tanzania
(Taylor & Francis Online, 2020-06-01) Kanagwa, Warda; Kilewa, Ramadhani; Treydte, Anna
Parthenium hysterophorus is an invasive weed that poses significant threats to crop production, biodiversity, human and animal health. Few experiments have been carried out to test the effectiveness of biological control agents such as the beetle Zygogramma bicolorata against this invasive. We released Z. bicolorata beetles as bio-agent to control P. hysterophorus at the Tropical Pesticides Research Institute in Arusha, Tanzania, across two seasons, from February – July 2019 (wet) and August 2019 – January 2020 (dry). Feeding by Z. bicolorata reduced P. hysterophorus leaves, flowers, height as well as biomass, both in the dry and wet season. During the wet season, 100% of all P. hysterophorus leaves were eaten already 28 days after the onset of the experiment, particularly under the highest beetle population treatment (30 individuals). Parthenium hysterophorus flower numbers were greatly reduced under high beetle populations (30 individuals) compared to the control treatment (0 individuals) during both the wet and dry season. Parthenium hysterophorus height was reduced by 87% and 90% during the wet and dry season, respectively when 30 beetles were released. Similarly, biomass was reduced by 90% and 87% during the wet and dry season, respectively. Parthenium hysterophorus responses to beetle treatments did not differ significantly across seasons but the development of both the invasive and its control, Z. bicolorata, was slightly delayed in the dry season. We conclude that Z. bicolorata can be used as bio-agent to manage P. hysterophorus in Tanzania, particularly when released in large numbers.
Environmental factors and non-chemical methods to suppress growth of the invasive plant Gutenbergia cordifolia
(Elsevier, 2023-08-01) Mero, Sarah; Ngondya, Issakwisa; Treydte, Anna
Little is known about preferred environmental conditions and non-chemical control of invasive Gutenbergia cordifolia. We assessed the effects of different A. annua crude extract concentrations, synthetic herbicide (glyphosate), fire regime and shade to G. cordifolia germination, shoot and root dry biomass, seedling height and leaf chlorophyll. High concentrations (75%) of A. annua crude extracts significantly reduced germination percentage of G. cordifolia by 25% (F2,4=77.2, p < 0.001), and suppressed shoot and root dry biomass (F2,4 = 80.3, p < 0.001; F2,4=46.104, p < 0.001, respectively) as well as seedling height and leaf chlorophyll (F2,4 = 12.02, p < 0.002; F2,4 = 15.9, p < 0.001), respectively. Medium temperature (60 °C) and long exposure time (5 min) significantly increased G. cordifolia germination percentage (F2,7 = 32.6, p < 0.001) while extreme temperatures (≥150 °C) at both (1 min) short and (5 min) long exposure time completely suppressed germination of G. cordifolia. Under high shade, while germination percentage was a third that of other treatments (F 2, 4 = 20.9, p = 0.008), mean germination took twice as long (F2, 4 = 17.9, p = 0.010) and shoot fresh biomass was reduced by half (F 2, 4 = 16.92, p = 0.004). Shoot and root dry biomass were reduced to more than a third under high shade, seedling height reduced to half but leaf chlorophyll content was not affected (F 2,4 = 6.3, p = 0.030; F 2,4 = 9.1, p = 0.020; F 2,4 = 18.3, p = 0.003; F 2,4 = 3.02, p = 0.120, respectively). We suggest using A. annua as a potential bio-herbicide and highlight considering fire and shade as suppressor tools to control G. cordifolia, but first include in-situ trials to assess their impacts to both native plants and animals.
EthnobotanicalknowledgeandthreatfactorsforAloespeciesinTanzania
(Ethnobotany Research & Applications, 2019-12) Abihudi, Siri; de Boer, Hugo; Mahunnah, Rogasian; Treydte, Anna
Background: The genus Aloe has long been known for its use in healthcare and cosmetics. In Tanzania, overexploitation is threatening some Aloe species with extinction and yet, little has been documented on the abundance and biocultural uses. Material and Methods: Semi-structured questionnaires were used to obtain ethnobotanical information from 236 respondents across 22 villages in four regions of Tanzania (Kilimanjaro, Tanga, Mara, Katavi-Rukwa). Results: A total of 23 Aloe species were identified, 20 of which were being used locally and were mostly being collected from the wild. We report the uses of A. mzimbana, A. volkensii subsp. volkensii, A. leptosiphon, A. parvidens and A. bicomitum for the first time in East Africa. The most preferred species were A. lateritia, A. duckeri and A. secundiflora which are three common, widely distributed species. Diseases frequently treated with Aloe species include malaria and general stomachache in humans, and Newcastle disease in chickens. Some Aloe species were found to have gone extinct locally due to over-harvesting. Rare Aloe species were perceived to be less preferred as they mostly occurred far away from settlements. Conclusions: We conclude that the genus Aloe is widely used across Tanzania and needs strong conservation measures to prevent individual species from becoming extinct in the wild.
Ethnobotany of Oyster nut ( Telfairia pedata) in Northern Tanzania
(Journal of Biodiversity and Environmental Sciences, 2022-01-12) Shayo, Philipina; Treydte, Anna; Mbega, Ernest
Telfairia pedata (Sims) Hook is an important native climber plant commonly grown in East Africa. It bears nuts which are eaten either raw or cooked and is consumed mostly by expectant mothers, and as cooking oil. The survey was conducted between September 2019 to February 2020 in Sambaa, Meru, and Pare communities of Lushoto, Bumbuli, Arumeru and Same Districts, Northern Tanzania to assess the ethnobotany of T. pedata from a sample of 346 respondents using semi-structured questionnaires. Results indicate that, 21% of respondents used T. pedata for cooking with other staple foods while 18% claimed that the nuts are used by pregnant and lactating mothers for medicinal and breast milk stimulation and nine (9) percent indicated that the nuts are used for cultural and ritual purposes. Despite its importance, the cultivation of T. pedata in the study area is declining and the gap why such decline is experienced needs to be answered in further studies. Secondly, respondents within the 36-50 age groups reported the greatest diversity of uses of T. pedata 51% compared with those aged below 36 years old 21% signifying that the traditional knowledge known by younger aged groups may be declining. Thus, this gap of traditional knowledge between the groups should be addressed in order to improve utilization and conservation of this seriously declining yet important nut in the study area and other places of Tanzania.
Fatty Acid Contents and Stability of Oyster Nut Oil (Telfairia pedata) Compared to Flaxseed and Sunflower Oil
(Hindawi, 2021-11-21) Mwakasege, Emmanuel; Treydte, Anna; Hoeglinger, Otmar; Kassim, Neema; Makule, Edna
The selection of healthy fats for consumption is important. Linoleic acid (LA) (omega-6) and alpha-linolenic acid (ALA) (omega-3) are essential polyunsaturated fatty acids required for the maintenance of good health; however, LA derivatives such as arachidonic acid (AA) are associated with the onset of inflammatory diseases, and both are prone to oxidation and deterioration. This study compared the fatty acid contents, peroxide value (PV), p-anisidine value (p-AV), and free fatty acids (FFA) of the oyster nut oil with refined sunflower, nonrefined sunflower, and flaxseed oil stored at 27°C for 40 days. Flaxseed oil had significantly high ALA content (59.8%) compared to 0.1-0.5% for oyster nut and sunflower oil brands. The LA content was high in sunflower brands (50.3-52.8%) compared to the oyster nut (48%) and flaxseed oil 14.7%. Oleic acid was lower in oyster nut oil (8.6%) and flaxseed oil 15.8% compared to sunflower brands (35.7-38.2%). As a consequence, oyster nut and flaxseed recorded higher PV of 4.35-2.88 mEq O2/kg and FFA 0.26-0.47% compared to sunflower brands. The p-AV recorded small values which were not significantly different in all samples. Although oyster nut is widely consumed by pregnant and lactating women across Africa, its keeping quality in nonrefined form is low compared to flaxseed and sunflower oil as shown in this study. Hence, the fatty acid contents in oyster nuts should be consumed in other alternative forms such as flour and roasted kernels rather than its oil when in nonrefined form. This study will enable the consumption balance of omega-6/omega-3 fatty acids and the keeping quality of oils which is key to health.
Growth performance of the neglected crop Telfairia pedata across elevation and climate gradients in Northern Tanzania
(Elsevier B.V., 2022-02-07) Shayo, Philipina; Mbega, Ernest; Treydte, Anna
Herbaceous vines, including the neglected crop Telfairia pedata, play a key role in small-holder livelihoods of Eastern Africa. Despite this species’ importance in enhancing agro-biodiversity, little is known about its distri- bution and growth performance in relation to environmental variables. We collected biophysical and environ- mental data, i.e., on climate and elevation, for 346 T. pedata vines across four districts of Northern Tanzania from September, 2019, to February, 2020. The four sites included Same, Lushoto, Muheza and Arumeru districts. We found that plants of T. pedata were mainly grown in elevations ranging between 900 to 1800 m above sea level with annual rainfall regimes of 1000 to 1400 mm. We recorded large abundance of T. pedata in Lushoto (46%) and Arumeru (28%) and observed that the number of fruits and fruit diameter were both positively correlated with elevation across the study districts. There was a significant effect of elevation on number of seeds, with Same district having more seeds across the studied districts. Rainfall had a significant effect on fruit diameter and number of seeds in the study districts. Furthermore, the tree species Albizia schimperiana was most commonly (in 40% of the cases) associated with T. pedata, followed by Persea americana (14%), and Croton macrostachyus (9%). We highlight that mountainous regions are ideal for this highly nutritious crop, and that native trees are of high importance for enriching this vine to current agro-ecosystems. Our findings will increase awareness on the importance of raising T. pedata crop, livelihood diversification, and increasing biodiversity through production of this orphan crop in small-holder farms. 1. Introduction Telfairia pedata (Smiths ex Sim) Hook or oyster nut belongs to Cur- cubitaceae family, which includes over 700 species and approximately 90 genera (Okoli and Mgbeogu, 1983; Odiaka et al., 2008; Chiamaka et al., 2020). It is a herbaceous woody vine and dioecious that bears squash-like fruits with large and nutritious oily seeds, is perennial and can withstand drought to some extent (Onovo et al., 2010; Ifeanyi-Obi et al., 2013), (Fig. 1). Telfairia pedata is mostly grown for its oilseeds in Tanzania including Zanzibar Island, and other African countries including Angola, Mozambique, coast of Kenya, Uganda and Nigeria (Schippers, 2000; Odiaka et al., 2008; Odiaka and Odiaka, 2011; Are- gheore, 2012). The nuts are highly valued by East Africa natives and are in great demand by breastfeeding mothers (Fubara-Manuel et al., 2012; Nwonuala and Obiefuna, 2015). These oilseeds are related to pumpkin seeds (Cucurbita moschata) which are also highly important for their therapeutic and functional (nutraceutical) values (Dotto & Chacha, 2020). Telfairia pedata nuts are mostly eaten raw or boiled, roasted for confectionery or grounded into a thick paste for use in staple meals such as soup thickening (Odiaka et al., 2008; Alegbejo, 2012). It contain protein, fat, carbohydrates, oleic acid, linoleic acid, stearic acid, pal- mitic acid, minerals including phosphorus (P), magnesium (Mg), po- tassium (K), iron (Fe) and calcium (Ca) (Aregheore, 2007; Mwakasege et al., 2021). In some cases, Telfairia species provide substantial cash income to small rural farm families and for biodiversity conservation (Akoroda, 1990; Alegbejo, 2012; Chukwurah et al., 2015). However, despite its household income generation, nutritional and environmental value, the cultivation of this crop in Tanzania has been neglected, and little is known about its distribution, growth performance and constraints. The climber grows well in presence of hard wood trees or wooden made structures, and it is regarded as an important component of the rich * Corresponding author. E-mail address: shayop@nm-aist.ac.tz (P.F. Shayo). Contents lists available at ScienceDirect Trees, Forests and People journal homepage: www.sciencedirect.com/journal/trees-forests-and-people https://doi.org/10.1016/j.tfp.2022.100216 Received 30 August 2021; Received in revised form 25 January 2022; Accepted 3 February 2022
How dynamics and drivers of land use/land cover change impact elephant conservation and agricultural livelihood development in Rombo, Tanzania.
(Taylor & Francis Group, 2017) Mmbaga, Naza; Munishi, Linus; Treydte, Anna
Land use/ land cover (LULC) change affects the provision of ecosystem services for humans and habitat for wildlife. Hence, it is crucial to monitor LULC particularly adjacent to protected areas. In this study, we measured LULC change in Rombo, Tanzania, an area with high potential agro-ecological zones that is dominated by Human Elephant Conflicts (HEC). We used remote sensing and geographical information system (GIS) techniques, questionnaires and village meetings to assess spatio-temporal patterns of the LULC changes in the study area. Using Landsat imagery, digital elevation model and ground truthing, we classified and monitored changes in LULC from the year 1987 to 2015. We found that within Rombo settlements were increasing while agricultural and agroforestry lands were decreasing and respondents’ perceptions varied along the altitudinal gradient. Patterns of HEC and LULC were observed to change along the gradient and the later threatened the agricultural land and ecological integrity for elephant habitat, leading to high tension and competition between elephants and people. This research offers baseline information for land use planning to balance wildlife conservation with livelihood development in Rombo and highlights that managing the impacts of LULC changes on HEC and elephant habitat loss is a matter of urgency.
How much to cut? Finding an optimal thinning intensity of encroaching woody species for the herbaceous community in an East African savanna
(Frontiers Media SA, 2025-01-06) Abate, Teshome; Abebe, Tesfaye; Treydte, Anna
Globally, bush encroachment poses a great threat to the conservation of biodiversity and rangeland productivity. However, control methods of encroaching woody species have rarely been experimentally quantified. We assessed the impact of tree thinning intensities on tree mortality, and the herbaceous community in Borana rangelands, an Ethiopian savannah ecosystem. At two 1.4 ha areas of mono-specific Vachellia drepanolobium stands, we set up 20 m x 10 m experimental plots with four tree-thinning treatments (0%, 33%, 67%, and 100% tree removal), with three replications in a randomized complete block design (RCBD) across two sites. The 0% plot was left uncleared and used as control. Over two growing periods, we monitored resulting tree mortality, coppicing, seedling mortality, and recruitment as well as herbaceous layer attributes (diversity, biomass) and the rangeland conditions. Tree thinning intensity significantly increased abundance of the dominant desirable grass species. Total herbaceous and grass species richness, diversity and biomass were significantly improved under high (100%) and moderate (67%) tree removal intensity. We conclude that tree thinning at moderate intensity (67%) was most effective in enhancing mortality of encroached trees, and improving grass diversity, and herbaceous biomass. We stress that effective tree thinning requires post-thinning management and repeated bush control measures. Our findings contribute to development of recommendations on controlling bush encroachment, species restoration, and rangeland productivity in Ethiopian rangelands.
Human population growth as indicator for human-elephant conflicts in Rombo area, Tanzania
(Journal of Biodiversity and Environmental Sciences (JBES), 2017-04-17) Mmbaga, Naza; Munishi, Linus; Treydte, Anna
Conservationists need detailed information on human population growth and distribution in areas adjacent to protected areas. This information can help determine land use/land cover changes (LULCC), which affect the quality and quantity of elephant habitat and, thus, elephant populations. We assessed the influence of human population trends on demographic characteristics on the African elephant (Loxodonta Africana) population and related conflicts with people in Rombo, Tanzania. Data on household surveys, focus group discussions, site observations and human census records as well as reported human-elephant conflict (HEC) incidents were included. A Digital Elevation Model in GIS was used to produce a map showing spatial distribution of human population density along an altitudinal gradient in relation to LULCC and HEC status. We found that, over the past 40 years, the human population in Rombo area has been growing fast, with an increment of 128% from 1967 to 2012. The population density was low in lower altitudes (<1230 masl), which were strongly used for seasonal cropping and highly dominated by HEC (98%). Settlements expanded from 1987 to 2015 by 30%, particularly at higher altitudes. Most respondents only attained primary education (72%) and strongly depended on agriculture (99%) to sustain their livelihoods. We conclude that with the increasing human population and alteration of land use need interventions to sustain elephant conservation and livelihood of the people. We recommend the establishment of buffer zones for elephant conservation and tourism activities in the lowland areas.