Copepod diversity along the Congo River Basin: a first approach

peer reviewedThe free-living copepods of the Congo River Basin in Africa, the second largest in the world just after the Amazonas River Basin, are still insufficiently known because of problematic accessibility and complex logistics related to sampling. We analyzed samples from 82 sites obtained during expeditions in 2010 and 2013. The Congo River main channel and its main mouth tributaries (1700km; between Kisangani and Kinshasa), and the Kasai River and its main mouth tributaries (600km) were visited. A Schindler-Patallas trap was used in the open waters, with five samplings at each site. Twenty-five taxa were found, with dominance of immature forms (nauplii and copepodites). We recognized three undescribed species of Cyclopoida. The most speciose genera were: Microcyclops (five species), Mesocyclops, , and (three species each). The most frequent species were: Microcyclops varicans (27,6% of the samples) and Cryptocyclops sp. (10,6%). Few presumably cosmopolitan species were found, like pocyclops prasinus, , and Microcyclops varicans. Few diaptomid calanoids were found. Rarefaction and extrapolation curves revealed that the diversity found is about half that estimated considering just the open water species here studied. Spatially, the highest species richness was found in the main channel of the Congo River (23) compared to Kasai (20) and other tributaries (14, 9 from the Congo tributaries, 6 from the Kasai). The abundance of adult individuals was low, with an average of 2,36 individuals per sample when considering all water bodies. A distance-based redundancy analysis based on abundance and Bray Curtis dissimilarity index revealed two large groups of copepod species in the sites of the Congo main channel, plus two minor groups with mixed sites among Congo and Kasai main channels, and tributaries of both rivers, the latter being represented by small groups correlated with nitrogen forms, total phosphorus, and oxygen concentrations. Concerning the two large Congo´s channel groups of species, one was associated with water transparency, chlorophyll, and phytoplankton dominated by Dinophyceae, Chlorophyceae, Cryptophyceae, and diatoms. The other was correlated with conductivity, chlorophyll-a and Cyanophyceae. Kasai main channel sampling sites were dispersed among the four groups resulting from our analysis. Our results indicate that the copepod species in the area are separated into two large groups associated with black and white waters, with low and high primary productivity, respectively. The results showed a high copepod diversity along the Congo Basin as expected for large tropical rivers, and a low abundance for the adult copepods, as in other lotic environments. More species are expected to be discovered in this basin with the continuation of this investigation

Neotropical and Afrotropical freshwater copepods: recent advances

peer reviewedI present new perspectives and advances on the knowledge of free-living copepods in large tropical river basins. Currently, the greatest copepod diversity is known from the Palearctic region, with a surface about twice or thrice that of the Neotropical and Afrotropical areas, respectively. Interestingly, biological diversity estimators suggest a much higher and largely unexplored diversity in the two latter regions, potentially reaching or exceeding that of the Palearctic. I show trends for both regions, focused on Brazil and Congo Basins. Brazil comprises almost 40 % of the Neotropical region surface, including four rivers among the 20 largest in the world. Based on the literature review, there are 190 free-living copepod species in the country. Among the 12 hydrographic regions in Brazil, the richest are the Amazon and the Paraná basins, with the largest surface. Taxonomical studies on Brazilian copepods were predominant until 1979, yet, between 1980 and 1989 ecologically-oriented works were developed and became a main trend after 1990, representing over 80% of copepod studies after 2000. Molecular diversity and functional ecology are still poorly studied. Ecological studies with molecular-based diversity parameters, functional attributes or comprehensive spatialtemporal data of copepod species behavior and environmental variables have been used to detect effects of environmental changes both at population and community levels. Cyclopoid copepods composition and abundance changes according to the trophic level, but calanoids appear to be influenced by conductivity. The presence of cyanobacteria and phytoplankton of lower nutritional value can cause a bottom-up effect on the copepods, resulting in low functional diversity and increase of functional uniformity. Large filtering copepods can be replaced by small cyclopoids at increasing eutrophicated conditions. The Afrotropical region comprises four of the largest rivers worldwide. The most studied environments have been the great lakes of the rift valley (e.g. Tanganyika, Victoria, Kivu), the Nile River, and several places in South Africa. The Congo River, the second largest in the world, is almost entirely unknown in terms of copepod composition and ecology. Herein, I show initial data revealing the lack of knowledge of the l extant Congo copepod diversity, with a high potential for new species. Two expeditions made in 2013 and 2015 along the Congo and the Kasai River revealed 15 copepod species, but rarefaction and extrapolation diversity curves suggest the presence of at least double of this number. There are four large groups of copepods species in the Congo Basin, being the two largest separated by differences in primary productivity (white waters rivers) or microbial food web (black waters rivers). Copepods within the main channel of the Congo River seem to be less dissimilar than tributaries, thus reinforcing the effect of upstream basins, a trend observed in other large tropical river basins. Each large river has different copepod species especially for diaptomid calanoids and also for some Cyclopoida species, but just the last have shared species between Afrotropical and Neotropical regions. The river continuum and the flood pulse concepts were applied in these large tropical rivers, but both were disrupted by reservoirs. The large rivers of these tropical regions appear seem proportionally equal in copepod diversity according to this surface, and linked to their historical biogeography

Kajian potensi ekstrak bilberi sebagai penunjuk pH untuk memantau kesegaran makanan secara kromametri

Penunjuk pH sebagai suatu pendekatan untuk memantau kualiti atau kesegaran makanan semasa telah mendapat perhatian industri pembungkusan makanan. Penggunaan sumber semula jadi pigmen tumbuhan terutamanya daripada buah-buahan dan sayur-sayuran menjadi pilihan para pengguna untuk menggantikan pewarna sintetik dalam memastikan keselamatan makanan yang diambil setiap hari. Dalam kajian ini, ekstrak daripada bilberi telah digunakan sebagai pewarna sensitif pH. Perubahan warna sampel dikaji secara terperinci melalui kaedah kromametri dan juga kaedah spektrofotometri ultra-lembayung nampak. Warna merah terang terhasil dalam pH berasid, merah pudar pada neutral dan magenta ke kuning dalam pH beralkali. Keputusan kajian kromametri menunjukkan bahawa ekstrak bilberi berupaya mempamerkan perubahan warna yang jelas terhadap perubahan pH, iaitu terdapat perubahan nilai warna a* yang menyumbang kepada perubahan yang bererti dalam perbezaan warna keseluruhan (ΔE*). Nilai ΔE* juga ditentukan wujud hubungan linear dan kuantitatif terhadap julat pH tertentu. Oleh yang demikian, ekstrak bilberi didapati berpotensi sebagai bahan sensor untuk pH dalam membangunkan satu sensor pH bagi memantau kesegaran makanan terutamanya hasilan laut berbungkus memandangkan tahap kerosakan produk tersebut berkait rapat dengan perubahan pH ke arah alkali

Shedding light on zooplankton diversity from the Congo River Basin

peer reviewedThe Congo River Basin is the second largest in the world, and its plankton biota remains completely unknown. We studied the zooplankton diversity across 1700 km of the main channel (from the cities of Kisangani to Kinshasa) and subsequently in the mouths of the 25 largest tributaries during 2013 (N=39), and across 500 km of Kasai-Kwa River and tributaries in 2015 (N=25). We recorded 135 zooplankton species (26 for Testate Amoebae, 56 for Rotifera, 27 for Cladocera and 26 for Copepoda). At least five cladoceran and four copepod species are new. A non-metric multidimensional statistical analysis with Bray Curtis dissimilarity revealed that the zooplankton composition within Congo main channel was more similar than within the mouths of several tributaries and the Kasai-Kwa River basin. In the later, the tributaries were distinct from each other and from the main channel of Kasai River. A distance-based redundancy analysis using Bray-Curtis dissimilarity on abundance data revealed two main groups of species and limnological variables, one comprising sites with high total suspended matter, conductivity, chlorophyll, phytoplanktonabundance (white water rivers), and other with sites with high transparency and dissolved organic carbon concentration (black water rivers). Zooplankton diversity was uniform in the Congo main channel and in the Kasai-Kwa River, with low difference among sites. There was also a distinct third group, unrelated to variables. This study reveals a high diverse zooplankton community in the Congo basin, with new species and distinct community between the studied rivers, but homogeneous along each one

Processus d’évaluation des incidences de la gouvernance des ressources naturelles par la méthode « matrice d’influence » au Burundi et Sud Kivu.

Le développement résulte des changements de comportement des gens. La recherche constitue son levier catalyseur. Toutefois, la conceptualisation et la méthodologie d’action restent des défis au cours du processus de transformation de la vie des paysages et des paysans cibles. La question pourrait être donc: quelle est la meilleure approche pour évaluer les projets et les programmes de recherche en Afrique qui permettra de tirer les meilleures leçons apprises des processus interactifs de gouvernance déclenchés au sein des organisations porteuses d’initiatives? La présente étude utilise les outils de la cartographie des incidences « outcome mapping » pour développer les principes d’évaluation des processus de gouvernance multi-acteurs locale sur la base de discussions en focus group, d’interactions avec les experts ainsi que des observations effectuées de mai à juillet 2012 sur les hautes terres du Burundi et du Sud-Kivu en RD-Congo. La démarche a été réalisée dans six sites couvrant deux pays. Il ressort qu’elle permet de cerner les incidences sur la base de variables socio-environnementales ciblées et d’articulations contraignantes perceptibles au cours des initiatives de gouvernance collective des ressources naturelles. Cette démarche pourrait être applicable dans des contextes similaires de gouvernance des ressources naturelles (GRN) dans les tropiques.Development stands as a result of changes in the people’s behavior and research plays the role of development catalyst. However, the conceptualization and methodology of action remain a challenge in the process of transforming lives and landscapes in the target areas. Hence, the question is: what is the best approach to evaluate projects and research programs in Africa to get the best lessons from interactive governance processes triggered within implementing organizations? This study uses outcome mapping tools to develop principles for assessing local governance processes based on multi-stakeholder focus group discussions, interactions with experts, as well as field observations conducted from May to July 2012 in the highlands of Burundi and South Kivu in DR Congo. The process has been described and tested in six sites covering two countries. It appears that the developed methological principles could help identify clearly the impact based on selected socio-environmental variables and perceived farmers’ constraints within collective governance initiatives implemented on the ground in the domain of natural resources management. The designed approach could seemingly be applicable in similar NRM contexts across the tropics beyond the great lakes of Africa

Une approche participative des interactions entre les hommes, femmes et la biodiversité de la forêt tropicale dans la région du lac Tumba, RDC

L'objectif du projet BIOSERF est d'évaluer la durabilité d'un écosystème de forêt tropicale humide dans l'Ouest de la République démocratique du Congo sous des pressions démographiques, sociétales et climatiques. Le projet se concentre sur les interactions entre la flore, la faune et la population humaine locale pour comprendre les processus modifiant la biodiversité et la disponibilité en services écosystémiques dans des zones tropicales humides. En collaboration étroite avec une ONG locale, il utilisera un modèle de végétation dynamique (CARAIB) qui sera associé à un modèle multi-agents, afin d'analyser l'utilisation de différents services écosystémiques comme par exemple la production de plantes médicinales, de bois et d'autres produits forestiers, ou de services liés à la création de réserves naturelles. Le modèle de végétation sera adapté pour prendre en compte les processus de régénération de plusieurs espèces de plantes, sélectionnées pour leur usage par les communautés humaines locales. Pour ce faire, une sélection de 5 espèces d'arbres utilisées fréquemment ou traditionnellement sera effectuée basée sur les résultats d'une enquête sociologique. Une étude combinée des communautés de disperseurs de graines permettra de prendre en compte leur rôle dans la régénération de la forêt. Le modèle multi-agents, quant à lui, devrait voir le jour lors d'un processus de modélisation d'accompagnement. Toutes les hypothèses de base de la modélisation peuvent être remises en cause durant le processus, au contact de la réalité du terrain. Cette méthode devrait permettre de mettre en débat les incertitudes liées à la notion de service écosystémique. A travers une approche post-normale, cette démarche de modélisation a pour vocation de faire dialoguer scientifiques, citoyens et décideurs et ceci afin d'améliorer la qualité du processus de prise de décision collective. La conception de différents scénarios permettra d'explorer différentes pistes de futurs possibles et/ou désirables.BIOSER

Need for harmonized long-term multi-lake monitoring of African Great Lakes

To ensure the long-term sustainable use of African Great Lakes (AGL), and to better understand the functioning of these ecosystems, authorities, managers and scientists need regularly collected scientific data and information of key environmental indicators over multi-years to make informed decisions. Monitoring is regularly conducted at some sites across AGL; while at others sites, it is rare or conducted irregularly in response to sporadic funding or short-term projects/studies. Managers and scientists working on the AGL thus often lack critical long-term data to evaluate and gauge ongoing changes. Hence, we propose a multi-lake approach to harmonize data collection modalities for better understanding of regional and global environmental impacts on AGL. Climate variability has had strong impacts on all AGL in the recent past. Although these lakes have specific characteristics, their limnological cycles show many similarities. Because different anthropogenic pressures take place at the different AGL, harmonized multi-lake monitoring will provide comparable data to address the main drivers of concern (climate versus regional anthropogenic impact). To realize harmonized long-term multi-lake monitoring, the approach will need: (1) support of a wide community of researchers and managers; (2) political goodwill towards a common goal for such monitoring; and (3) sufficient capacity (e.g., institutional, financial, human and logistic resources) for its implementation. This paper presents an assessment of the state of monitoring the AGL and possible approaches to realize a long-term, multi-lake harmonized monitoring strategy. Key parameters are proposed. The support of national and regional authorities is necessary as each AGL crosses international boundaries

Need for harmonized long-term multi-lake monitoring of African Great Lakes

To ensure the long-term sustainable use of African Great Lakes (AGL), and to better understand the functioning of these ecosystems, authorities, managers and scientists need regularly collected scientific data and information of key environmental indicators over multi-years to make informed decisions. Monitoring is regularly conducted at some sites across AGL; while at others sites, it is rare or conducted irregularly in response to sporadic funding or short-term projects/studies. Managers and scientists working on the AGL thus often lack critical long-term data to evaluate and gauge ongoing changes. Hence, we propose a multi-lake approach to harmonize data collection modalities for better understanding of regional and global environmental impacts on AGL. Climate variability has had strong impacts on all AGL in the recent past. Although these lakes have specific characteristics, their limnological cycles show many similarities. Because different anthropogenic pressures take place at the different AGL, harmonized multi-lake monitoring will provide comparable data to address the main drivers of concern (climate versus regional anthropogenic impact). To realize harmonized long-term multi-lake monitoring, the approach will need: (1) support of a wide community of researchers and managers; (2) political goodwill towards a common goal for such monitoring; and (3) sufficient capacity (e.g., institutional, financial, human and logistic resources) for its implementation. This paper presents an assessment of the state of monitoring the AGL and possible approaches to realize a long-term, multi-lake harmonized monitoring strategy. Key parameters are proposed. The support of national and regional authorities is necessary as each AGL crosses international boundaries