Tropical Rainforest Belt Research Articles

Epiphyllous Liverworts from Batanta Island (Indonesia, West Papua) III

The epiphyllous liverwort collection was continued after the Covid pandemic in 2023 at the low and medium elevations of Batanta Island in the tropical rainforest belt by the entomolo-gist Tibor Kovács and his colleagues, which were identified by Tamás Pócs. The collection resulted in 35 species of which 9 liverworts proved to be new to Batanta Island along the species already known from the previous collections: Cheilolejeunea trapezia, Cheilolejeunea vittata, Cololejeunea schmidtii, Cololejeunea tenella, Colura herzogi, Drepanolejeunea cyclops, Leptolejeunea maculata, Microlejeunea punctiformis, and Radula javanica. Further three taxa are new even to science: Cololejeunea tiberii, Cololejeunea touwii subsp. batantae subsp. nov. and Drepanolejeunea levicornua var. incurviloba var. nov., which were described and illustrated by macro and microphotos. One previous identification was corrected. The results of 7 years of collecting activity resulting in 48 epiphyllous liverwort taxa known from Batanta Island are summarised.

Abundance and diversity of man-biting mosquito species in the tropical rainforest belt of Southeastern Nigeria

Abundance and diversity of man-biting mosquito species in the tropical rainforest belt of Southeastern Nigeria

The Luki and Yangambi Biosphere Reserves: laboratories for climate change research and sustainable development

The UNESCO Biosphere reserves of Yangambi (235 000 ha) and Luki (33 000 ha) are both situated within the semi-deciduous moist forests of the Democratic Republic of the Congo. These forests are part of the second largest tropical rainforest belt in the world and signify still a persistent carbon sink, rich in biodiversity and an essential provider of ecosystem services, including natural resources for economic development. Luki and Yangambi offer, thanks to the concept of Biosphere Reserve, an appealing opportunity to develop activities of research, training and education and serve, as such, as potential models for the reconciliation of nature conservation, economy and welfare. Both Yangambi and Luki have a particularly rich history of research. They can be considered as the cradle for investigations in Central-African botany, forest ecology, tree physiology, climatology, tropical agronomy and sylviculture. The archives, databases and scientific reference collections (curated both locally and in natural history collections in Belgium) related to these reserves are a treasure trove for actual research needs in the domains of global change (evaluations of carbon fluxes) and forest resilience. Some experimental plots are still present after their establishment, 70 years ago, and offer unique research material, in a region where there is a dire need for long term observations of vegetation dynamics and environmental fluctuations. We give an overview of ongoing research projects relevant to the topics of carbon fluxes and forest resilience, all including wood analysis in a context of vegetation history, tree physiology and forest ecology. We show how this is relevant for designing biodiversity management and we demonstrate how the MAB reserves of Luki and Yangambi are key research sites to document the debates on global changes and resilience of rainforests.

Did Global Warming and Climate Change Cause the Degradation of Lake Chad, Africa's Most Important 'Ecological Catastrophe'?

This paper explores six hypotheses/theories on Lake Chad’s degradation: i) natural climate variation; ii) anthropogenic climate change compounded the effects of the Sahel drought; iii) unregulated exploitation of Lake Chad’s hydrologic system overdrew the regenerative potential of the lake system; iv) high rates of deforestation in the tropical rain forest belt of West-Central Africa shifted the rain belt Southwards; v) pressure from rapidly expanding human and livestock populations exceeded the carrying potential of the Lake Chad ecosystem; and vi) anthropogenic aerosol emissions in the northern hemisphere shifted the tropical rain-belt southwards. The evidence shows that there is no single-cause explanation for Lake Chad’s degradation; rather the influence of global warming and climate change compounded those from pre-existing drought conditions and non-climate factors e.g unregulated exploitation of Lake Chad’s hydrologic system to degrade the lake.

Development of a composite soil degradation assessment index for cocoa agroecosystems in southwestern Nigeria

Abstract. Cocoa agroecosystems are a major land-use type in the tropical rainforest belt of West Africa, reportedly associated with several ecological changes, including soil degradation. This study aims to develop a composite soil degradation assessment index (CSDI) for determining the degradation level of cocoa soils under smallholder agroecosystems of southwestern Nigeria. Plots where natural forests have been converted to cocoa agroecosystems of ages 1–10, 11–40, and 41–80 years, respectively representing young cocoa plantations (YCPs), mature cocoa plantations (MCPs), and senescent cocoa plantations (SCPs), were identified to represent the biological cycle of the cocoa tree. Soil samples were collected at a depth of 0 to 20 cm in each plot and analysed in terms of their physical, chemical, and biological properties. Factor analysis of soil data revealed four major interacting soil degradation processes: decline in soil nutrients, loss of soil organic matter, increase in soil acidity, and the breakdown of soil textural characteristics over time. These processes were represented by eight soil properties (extractable zinc, silt, soil organic matter (SOM), cation exchange capacity (CEC), available phosphorus, total porosity, pH, and clay content). These soil properties were subjected to forward stepwise discriminant analysis (STEPDA), and the result showed that four soil properties (extractable zinc, cation exchange capacity, SOM, and clay content) are the most useful in separating the studied soils into YCP, MCP, and SCP. In this way, we have sufficiently eliminated redundancy in the final selection of soil degradation indicators. Based on these four soil parameters, a CSDI was developed and used to classify selected cocoa soils into three different classes of degradation. The results revealed that 65 % of the selected cocoa farms are moderately degraded, while 18 % have a high degradation status. The numerical value of the CSDI as an objective index of soil degradation under cocoa agroecosystems was statistically validated. The results of this study reveal that soil management should promote activities that help to increase organic matter and reduce Zn deficiency over the cocoa growth cycle. Finally, the newly developed CSDI can provide an early warning of soil degradation processes and help farmers and extension officers to implement rehabilitation practices on degraded cocoa soils.

The Use of Tithonia diversifolia L. as Soil Amendment and Its Effect on the Growth and Yield of Amaranthus cruentus in a Tropical Rain Forest Belt

The Use of Tithonia diversifolia L. as Soil Amendment and Its Effect on the Growth and Yield of Amaranthus cruentus in a Tropical Rain Forest Belt

ANTIBACTERIAL ACTIVITIES OF HONEY FROM DIFFERENT LOCATIONS IN THE TROPICAL RAIN FOREST BELT OF NIGERIA, ON SELECTED BACTERIAL ISOLATES

Honey has been used for various purposes including treatment of diseases. This study was carried out to determine antibacterial activities of honey samples obtained from different locations in the tropical Rainforest Belt of Nigeria (Abeokuta, Aiyetoro, Ajebo, and Saki) against reference bacterial isolates: Escherichia coli (E.coli) (ATCC 25922) and Staphylococcus aureus (ATCC 25923), using agar well diffusion technique. Staphylococcus aureus showed sensitivity to all honey samples used with the zone of inhibition ranging between 1.9 and 2.6mm. Escherichia coli was resistant to all concentrations of honey samples used. However, the present study did not explore the possible causative agent(s) involved in the antibacterial activity of the honey used.

Cesarean delivery in preeclampsia and seasonal variation in a tropical rainforest belt

The pathogenesis of preeclampsia is poorly understood and recent evidence suggests that the incidence varies depending upon the season. This study was carried out to determine whether there is a seasonal variation in the presentation of preeclamptics undergoing cesarean delivery in a tropical rainforest belt. A university teaching hospital. Retrospective. The hospital records of consecutive patients (July 1996-June 2006) with preeclampsia, who underwent cesarean delivery in a tertiary care centre, were reviewed. Data collected included patient demographics, total number of deliveries, number of cesarean deliveries, and number of preeclampsia patients and time of presentation for cesarean section. Approval of the local ethical committee was obtained. The EPI info software program was used for statistical analysis. A total of 6798 deliveries were recorded during the study period resulting in 6485 live births. There were 1579 cesarean deliveries during the period. Of these, 196 patients had toxemia of pregnancy (166 with preeclampsia and 30 with eclampsia). One hundred and forty-one patients (9% of cesarean deliveries) had cesarean delivery during the rainy season and 55 (3.5%) during the dry season (P < 0.05). Amongst preeclampsia patients, 115 presented (7%) during the rainy season and 51 (3.2%) during the dry season (P < 0.05). In the eclampsia group, 26 (1.65% of cesarean sections) presented during the rainy season and four (0.25%) during the dry season (P < 0.05). There was a seasonal variation in the cesarean delivery required for preeclampsia/eclampsia patients. This may help in counseling women on when to plan their pregnancy in order to reduce the morbidity and mortality associated with this apparent seasonal disease.

A Holocene vegetational and climatic record from the Atlantic rainforest belt of coastal State of São Paulo, SE Brazil

Holocene vegetation and climate have been reconstructed by means of pollen analysis in a 643-cm-long core from the Jacareı́ peat deposits (23°17′S, 45°58′W, 550 m a.s.l.) within the Atlantic tropical rainforest belt in the State of São Paulo, SE Brazil. Three conventional 14C dates indicate that the onset of peat formation started at 9720 years BP. Due to sampling restrictions, the record encompasses the period between 9720 and ca. 1950 years BP. The palynological content of the samples permitted the recognition of five distinct climatic periods between 9700 and ca. 1950 years BP: humid and cool climate from 9720 to ca. 8240 years BP, humid and warm from ca. 8240 to ca. 3500 years BP, cooler and moister than today from 3500 to 1950 years BP. The return of a cool climate at the late Holocene is suggested by the reappearance of montane and humid forest taxa such as Araucaria, Drimys, Daphnopsis, Ericaceae, Podocarpus and Myrsine in the upper sections of the pollen diagram. Throughout its formation, the Jacarei peatbog has had a very different botanical composition. Gleichenia was the most important taxon in the peat bog from 9720 to 8240 years BP, followed by Selaginella, Polypodium and Asplenium until 5400 years BP. A Sphagnum/ Lycopodium dominated peat was established from 5400 to 3500 years BP, followed by Gleichenia/ Sphagnum from 3500 to ca. 1950 years BP. The interpretation of the pollen and spore diagrams permitted a correlation between the vegetational and climatic signal contained in the Jacareı́ peatbog with other locations in southeastern and southern Brazil.

Management Practices And Ecological Status Of A Humid Tropical Rainforest

This study attempts to put in perspective the spatial and floristic variations, which exist in the tropical rainforest belt of Nigeria by virtue of different management practices. The variations were examined by comparing the floristic and biomass properties of a government-managed forest with that of an adjacent community-managed forest in the same eco-climatic zone. A floristic similarity of 38.4% was observed between the two sites, while the species richness of the two sites were not significantly different, despite the different management regimes. A classification of the tree species found on both sites using Principal Component Analysis (PCA) revealed that savanna elements were gradually being introduced into the community-managed forest. However, this variation may be presumed to be temporal if forest management by rural dwellers is monitored or guided by responsible government agencies.

Agricultural colonisation and floristic degradation in Nigeria's rainforest ecosystem

This paper attempts to characterise the common tree species that are now found in the tropical rainforest belt of Nigeria. The occurrence of species present in at least 10 percent of the quadrats studied were generated from field data. Simple correlation analyses were used to examine the strength of relationships among the species in the data sets. The results show that the nature and intensity of agricultural activities have influenced the types of floristic association found within different areas of the region. The ecological grouping of the species in the region shows distinct areas where regressive succession has led to floristic degradation of the rainforest belt.

The Prevalence of Onchocerciasis and other Parasitic Infestations on an Oil Palm Plantation in Ghana

This study was carried out amongst workers of Twifo Oil Palm Plantations (TOPP), a large agro-based industry located in the tropical rain forest belt of the Central Region of Ghana in West Africa. The district abounds in streams and rivers, the biggest being the rapidly flowing River Pra which bisects the district. Simulium flies abound in the area and are commonly seen biting voraciously especially during the period of the year when farm lands are being prepared for cropping. The author assumed the responsibility of providing health care for about 1700 employees of the plantation and their dependents in 1988. The majority of employees had been engaged without any pre-employment medical examination. Available medical information on most workers was inadequate and limited to those reporting to the small company clinic. There was no hospital in the district and the deplorable roads turned the district into an inaccessible island. Meaningful planning for healthcare delivery in the area was difficult. This study was conceived as an initial step in identifying the common health problems particularly amongst the plantation workers in order to plan necessary interventions.

Large Scale Crossbreeding of Bos Indicus with Bos Taurus in the Tropical Rain Forest Climate of Kerala in South India

The state of Kerala in India has predominantly an agrarian economy, with crop production providing the major income for farmers. The economy is also supported by animal husbandry in many of the farm households. Geographically Kerala lies in the tropical rain forest belt with a two season pattern and two monsoons spread over eight months. The main food crops are paddy and tapioca, while the cash crops grown are coconut, rubber, pepper, cashews, tea, coffee and spices. The population density is one of the highest in the world with 654 people per km2, therefore placing extraordinary pressure on land availability for crops and cattle. The native non-descript zebu-type cattle of Kerala, evolved over long periods, are poor in milk and reproductive performance but have adapted very well to the tropical environment with regards to heat and disease resistance. The local zebu are small in stature with an average body weight of 150-250 kg standing 1.1-1.2 meters high. The average age at first calving is 51 months and the average lactation yield is estimated at 500-700 kg/200 days.1,2 The average calving interval is long at 21 months2. The number of AI per conception is 2. 4 for field animals2.These non-descript zebu type cattle could not satisfy the milk needs of the state. To improve the milk production to 1500 L per lactation by genetic improvement alone would have taken 150-200 years. Replacement of local stock with exotic dairy breeds was not practical. Past experience has shown that transplantation of such temperate breeds into the tropical rain forest climate is not economical because of poor adaptability, susceptibility to tropical diseases and non-availability of suitable management. Therefore, a programme of limited crossbreeding of local zebu cattle with Bos taurus dairy breeds was implemented as a practical means enhancing the milk yield. Crossbreeding offered the most promising approach to evolve a type of cow which could be maintained economically under prevailing village conditions. The purpose of this paper is to present data supporting crossbreeding between local nondescript milk breeds with top genetic material of temperate Bos taurus milk breeds, as the best currently available means to converse local poor producing cattle into crossbreds of high productivity.

The effect of monthly planting on yield, yield patterns and yield decline of plantains ( Musa AAB)

This study investigated the effect of monthly planting throughout the year on the yield, yield patterns, wind damage and yield decline of plantains in the tropical rainforest belt for 3 consecutive harvest cycles. Yield of plant-crop plantains increased from February to October plantings, though with significant variations. Plantains established between January and May matured twice during the dry season in a 3-year harvest cycle, resulting in 25–35% wind damage and over 25% yield decline. However, except for the lower 80% for the September–November survival count, plantains established between July and December experienced minimum (10–15%) wind damage, produced significantly ( P = 0.05) higher and sustained yield (t ha −1), and matured in unfavourable weather only once in every 3-crop harvest cycle. Optimum 3-crop total plantain yields were obtained when the suckers were planted in August–December. The practical implications on the conventional planting season among growers are discussed.

The Tropics as the Norm in Biogeography?

inputs vary, but still this is a common characteristic for most of the biomes about which we will be taking. When we come, however, to consider precipitation, it is a little more difficult, because regions with this high radiant energy input embrace areas ranging from those with plentiful rainfall and high humidity throughout the year to nearly rainless deserts and through many climates with complex gradations between these two extremes. When we consider the concept of 'the norm', therefore, we may well be forced to limit our definition to, say, a true core area, such as the genuine lowland tropical rain forest and Koppen's Af climates. The tropics are also a region in which chemical and biological changes are noted for their speed of reaction, and we shall have to see whether the speed and nature of these reactions differ by degree only or in fundamental principle from those obtaining elsewhere on the globe. And, finally, we must accept, initially at least, a traditional view of the lowland tropical rain forest belt, namely that it is very old and has been but little affected by the climatic and other environmental changes incident on the Quaternary glaciations. However, I suspect that Dr Flenley may have a few caveats to enter concerning that common view and we may have to consider anew the so-called stability of a core community of lowland tropical rain forest. Let us now consider the second word, that enigmatic concept of a 'norm'. The main thesis underlying the question mark of this meeting is that, perhaps, because so much biogeographical and ecological theory has been developed from work in the boreal and temperate regions of the world, this theory has turned what is essentially the abnormal?the simple and the geologically young?into the normal, and that it could be misleading to have developed most of our basic principles in regions with soils and vegetation which are, in the main, less than 10 000 years old. Should not the tropics be the norm for developing theory and basic principles and not these clearly juvenile and ill-developed areas? I shall quote, as an example of the dilemma, one extreme instance. If the wilder theories of certain writers, such as those of the Russian, Federov (1966), were proved to have substance, and speciation (the creation of new species) in lowland tropical rain forest was seen to be governed by the random processes of genetic drift and not the clearly adaptive neo-Darwinistic principles of natural selection, then there would be no obvious and essential ecological relationship between habitat and species. The fundamental tenet of most ecological thinking would, in fact, be brought into question. This extreme case illustrates well the problem which we are confronting. In this instance, the differences would not be of degree only, but of principle. Many workers, on the other hand, regard the differences as of degree rather than of principle. The

ORIGIN OF DECIDUOUS AND EVERGREEN HABITS IN TEMPERATE FORESTS

Deciduous hardwood forests in temperate parts of the Northern Hemisphere, brilliantly colored in autumn and leafless in winter, provide a striking contrast with the somber broadleafed forests that extend to tree line in the temperate Southern Hemisphere and remain green through the year. These northern and southern temperate forests are also very dissimilar in composition, for the genera differ in each area and most of them belong to divergent families. The fossil record suggests that the morphologic differences between the plants that contribute to these forests are the result of their independent evolution on opposite sides of the tropical rainforest belt during Cretaceous and later times. Presumably the deciduous and evergreen habits displayed by woody plants in boreal and austral regions reflect fundamental differences between the environments in which they evolved. However, the factors that may account for the presence of a predominantly deciduous habit for woody angiosperms in the temperate forests of one region as opposed to typically evergreen in the other, are obscure, as is the evolution of the deciduous habit itself in northern temperate hardwood forests. In searching for clues to the factors that may have been responsible for the origin of these contrasting habits, it is desirable to turn first to evidence provided by plants living in environments where gradual gradients can now be observed between the evergreen and the deciduous habit.