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L. Triest

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Portland State University

Kansas State University

Klaus-Holger Knorr

University of Münster

Francisco Malta Romeiras

Universidade de Lisboa

António Bento-Gonçalves

Universidade do Minho

Bucknell University

Virginia Tech

Vanderbilt University

University of San Francisco

Fabrizio Baldassarri

Università degli Studi di Milano - State University of Milan (Italy)

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Papers by L. Triest

Biogeographical patterns of Ruppia in the Mediterranean: new insights into diversity and dispersal

International Conference on Mediterranean Temporary Ponds, 2009

Checklist van de Vlaamse vaatplanten 1993: naar een flora - statistiek voor Vlaanderen : een nuttig instrument voor het natuurbehoud

Outbreeding depression and breeding system evolution in small, remnant populations of Primula vulgaris: consequences for genetic rescue

Conservation Genetics, 2017

Many species suffer from anthropogenic habitat fragmentation. The resulting small and isolated po... more Many species suffer from anthropogenic habitat fragmentation. The resulting small and isolated populations are more prone to extinction due to, amongst others, genetic erosion, inbreeding depression and Allee-effects. Genetic rescue can help mitigate such problems, but might result in outbreeding depression. We evaluated offspring fitness after selfing and outcrossing within and among three very small and isolated remnant populations of the heterostylous plant Primula vulgaris. We used greenhouse-grown offspring from these populations to test several fitness components. One population was fixed for the pin-morph, and was outcrossed with another population in the field to obtain seeds. Genetic diversity of parent and offspring populations was studied using microsatellites. Morph and population-specific heterosis, inbreeding and outbreeding depression were observed for fruit and seed set, seed weight and cumulative fitness. Highest fitness was observed in the field-outcrossed F1-population, which also showed outbreeding depression following subsequent between-population (back) crossing. Despite outbreeding depression, fitness was still relatively high. Inbreeding coefficients indicated that the offspring were more inbred than their parent populations. Offspring heterozygosity and inbreeding coefficients correlated with observed fitness. One population is evolving homostyly, showing a thrum morph with an elongated style and high autonomous fruit and seed set. This has important implications for conservation strategies such as genetic rescue, as the mating system will be altered by the introduction of homostyles.

Imbalance of Ecosystem Services of Wetlands and the Perception of the Local Community towards their Restoration and Management in Jimma Highlands, Southwestern Ethiopia

Wetlands, 2016

Wetlands provide vital services for the livelihoods of local peoples; however, the ecological int... more Wetlands provide vital services for the livelihoods of local peoples; however, the ecological integrity of wetlands in Ethiopia has not yet been studied. In this study, we investigated the main ecosystem services of wetlands among different land use types, incorporating local perception toward wetland management. Six wetlands were selected from forested, agricultural and urban areas in the Jimma highlands. A total of 332 local residents within a 5-km radius of each wetland were surveyed. An additional 34 development agents and district and zonal experts were interviewed. The provisioning and cultural services were found to surpass the regulatory and supporting services of wetlands in agricultural and urban land uses compared with wetlands located in the forest. Although most individuals positively viewed wetland regulation and supporting services, the majority of households (66 %) were not interested in conserving wetlands because of small landholdings and the need to meet their livelihoods. Consequently, the vital regulatory and supporting services of impacted agricultural and urban wetlands are gradually becoming limited. Urgent action is, therefore, required to restore and protect these wetlands by promoting alternative livelihoods and improving the agricultural productivity of small landholders.

Chloroplast microsatellite markers reveal Zannichellia haplotypes across Europe using herbarium DNA

Belgian Journal of Botany, May 31, 2007

... Zannichellia palustris subsp. repens Z6 Lith Brabant The Netherlands F 6 Z7 Klejtrup sø Vibor... more

Ontwikkelen van een monitoringsysteem en een beoordelingsmethode voor macrofyten in oppervlaktewateren in Vlaanderen overeenkomstig de Europese Kaderrichtlijn Water

Ontwikkelen van een score of index voor het biologisch kwaliteitselement 'macrofyten' voor de Vla... more Ontwikkelen van een score of index voor het biologisch kwaliteitselement 'macrofyten' voor de Vlaamse rivieren en meren overeenkomstig de Europese Kaderrichtlijn Water. Uittesten van de Europese ontwerphandleiding 'REFCOND' voor dit kwaliteitselement in Vlaanderen (VMM.AMO.KRW.ECO2.2002). Opdrachtgever: Vlaamse Milieumaatschappij (VMM) Opdrachthouder: Instituut voor Natuurbehoud (coördinatie) in samenwerking met Nationale Plantentuin van Meise,

The genus Ruppia L. (Ruppiaceae) in the Mediterranean region: An overview

Aquatic Botany, 2015

This paper reviews the current knowledge on the diversity, distribution and ecology of the genus ... more This paper reviews the current knowledge on the diversity, distribution and ecology of the genus Ruppia L. in the Mediterranean region. The genus Ruppia, a cosmopolitan aquatic plant complex, is generally restricted to shallow waters such as coastal lagoons and brackish habitats characterized by fine sediments and high salinity fluctuations. In these habitats Ruppia meadows play an important structural and functional role. Molecular analyses revealed the presence of 16 haplotypes in the Mediterranean region, one corresponding to Ruppia maritima L., and the others to various morphological forms of Ruppia cirrhosa (Petagna) Grande, all together referred to as the "R. cirrhosa s.l. complex", which also includes Ruppia drepanensis Tineo. Populations of hybrid origin between R. maritima and R. cirrhosa and polyploidy have been detected.

First Record of Najas setacea (A. Br.) Rendle from Continental Africa

Bulletin du Jardin botanique national de Belgique / Bulletin van de National Plantentuin van België, 1988

Isozyme Patterns and Taxonomic Position of a Central African Population of Najas Marina L. Subsp. Armata (Lindb. f.) Horn af Rantzien

Bulletin du Jardin botanique national de Belgique / Bulletin van de National Plantentuin van België, 1985

... In the present paper we consider a population of the African subsp. armata (Lindb. f.) Horn a... more

Monograph of the African Genus Lagarosiphon Harvey (Hydrocharitaceae)

Bulletin du Jardin botanique national de Belgique / Bulletin van de National Plantentuin van België, 1983

... Fl. Afr. 5 : 1 (1894); Wright in This.-Dyer, Fl. Trop Afr. 7 : 4 (1897); Andrews, Flow. Pl. S... more ... Fl. Afr. 5 : 1 (1894); Wright in This.-Dyer, Fl. Trop Afr. 7 : 4 (1897); Andrews, Flow. Pl. Sudan 3: 227 (1956). - Type : Sudan, &amp;lt;&amp;lt; Arasch-Cool ,,, Kotschy 170 (holo-B &amp;#x27;; lecto-G; iso-BM, K, L, MPU, P, Z). - Fig. 5. Udora cordofana Hochst. in sched. pl. exs. Kotschyi, It. Nubic. ...

Genetic differentiation between Bruguiera gymnorhiza and B. sexangula in Sri Lanka

Diversity and Function in Mangrove Ecosystems, 1999

The identification of populations of Bruguiera sexangula, Bruguiera gymnorhiza and their putative... more The identification of populations of Bruguiera sexangula, Bruguiera gymnorhiza and their putative hybrids in the field is difficult using only morphological and phenological characters. Using a PCR based technique, RAPD (Random Amplified Polymorphic DNA), the genetic variation of Bruguiera populations was studied from contrasting climatic and geographic regions along the southwest coastal region of Sri Lanka. Out of 45 primers screened, 20 primers allowed us to observe polymorphism, not only between species (interspecific) but also within the species (intraspecific). Analysis of RAPD data appears to be helpful in determining the genetic relationship among populations of B. gymnorhiza and B. sexangula. RAPD markers revealed that the two species are well separated without any hybrid position between the two taxa though they occur in mixed stands. Although sampling sizes of populations of this study were small, genetic variation among B. gymnorhiza and B. sexangula populations could be observed. For B. sexangula, it was possible to differentiate each of the three populations, even when using a small number of primers.

Strong isolation by distance revealed among Cyperus papyrus populations in the Rift Valley lakes, Lake Victoria, and isolated wetlands of Kenya

Aquatic Botany, 2015

Many aquatic plant populations occur in isolated habitats surrounded by land masses which can act... more Many aquatic plant populations occur in isolated habitats surrounded by land masses which can act as barriers to gene flow, unless other mechanisms exist to facilitate connectivity. This isolation together with life history processes influences greatly genetic diversity and structure among populations of aquatic species. We assessed clonal diversity, genetic variation, and genetic structure of Cyperus papyrus that occur in large geographical scale in freshwater wetlands of Kenya using eight nuclear microsatellite markers. A total of 60 alleles were found across 14 populations. The genetic diversity measures varied widely among populations, with both Lakes Naivasha and Victoria displaying higher allelic and gene diversity than isolated wetlands. C. papyrus maintained relatively high levels of clonal diversity and gene diversity at species level (P P = 79%, A T = 25, H E = 0.41, H O = 0.40) comparable to other clonal aquatic plants. Whereas, two monoclonal wetlands suggested recent founder effects, we attributed variation in clonal diversity to different levels of sexual reproduction and perennation among populations. AMOVA revealed overall high genetic differentiation among populations (F ST = 0.250, p = 0.001) which varied from very low (F ST = 0.014) within lakes to very high (F ST = 0.565) among Lake Victoria-Rift Valley lakes and isolated wetlands. Lack of genetic differentiation among populations within Lakes Victoria and Naivasha implicated hydrochorous dispersal. A Mantel test showed significant isolation-by-distance among populations whereas a PCoA and Bayesian analysis of individuals grouped populations according to drainage basins. We hypothesized that connectivity among distant isolated locations could be by migratory waterfowl or large herbivores (through both endozoochory and epizoochory) and historical inter-basin connection.

Toxicite d'Ambrosia maritima L., plante molluscicide, sur les organismes aquatiques non-cibles

Toxicon, 1991

Toxicité d'Ambrosia maritima L., plante molluscicide, sur les organismes aquatiques non~ibles. To... more Toxicité d'Ambrosia maritima L., plante molluscicide, sur les organismes aquatiques non~ibles. Toxicon 29, 745-750, 1991 .-La toxicité de la plante molluscicide, Ambrosia maritima L., a été testée chez des poissons, des crustacés et des algues. En utilisant la poudre ou un extrait éther-méthanol-hexane des feuilles de la plante, la t' .l . sp pour les alevins de Lebistes reticulatus (guppy) est respectivement 650 et 450 mgJlitre. Ceci est nettement plus élevé qua la concentration molluscicide de 35 à 70 mgflitre utilisée sur le terrain (canaux d'irrigation) en Egypte . Un degré similaire de toxicité a été observé dans des tests préliminaires sur des juveniles de L. reticulates et de Tilapia sures. En utilisant le même extrait d'A . maritima la ~so pour Daphnia magna est de 766 mg/litre et il n'y a pas de toxicité sur l'algue Selenastrum capricornutum à 1 goitre . Ambrosia maritima semble donc avoir une très faible toxicité pour les organismes aquatiques non~ibles. A la dose molluscicide de 35 à 70 mg/litre il n'y a pas d'effets toxiques . F . ALtutn, S. G1~leTS and L. TRII?sT. Toxicity of the molluscicidal plant, Ambrosia maritima L., to aquatic non-target organisms. Toxicon 29, 745-750, 1991 .-The toxicity of the molluscicidal plant, Ambrosia maritirna L., has been evaluated in fish, crustacea and algae. The Lc,~for fries of the guppy, Lebistes reticulates, was respectively 650 and 450 mg/litre using a powder or an ether-methanol-hexane extract from the leaves of the plant. This concentration is much higher than the molluscicidal concentration (LCD of 35 to 70 mg/litre, which is used in the field (irrigation canals in Egypt) . Preliminary tests showed that juveniles of L. reticulates and Tilapia sures were as sensitive as the fries. Using the same extract of A. maritima the Lcm for Daphnia magna was 766 mg/litre and no toxic effects could be observed in algae Selenastrum capricormttum at 1 g,/litre . It can be concluded that A. maritima has a very low toxicity to aquatic non-target organisms. It is not toxic when used at the molluscicidal concentration of 35 to 70 mg/litre.

The use of random amplified polymorphic DNA (RAPD) for hybrid detection in Scirpus from the river Schelde (Belgium)

Molecular Ecology, 1999

Along the unique freshwater tidal zone of the river Schelde (Belgium), plants of Scirpus species ... more Along the unique freshwater tidal zone of the river Schelde (Belgium), plants of Scirpus species occur primarily in small and fragmented populations. The majority of these are native Scirpus lacustris, S. pungens, S. triqueter, S. tabernaemontani and intermediate morphological forms. The distribution area of S. triqueter is even restricted to this tidal habitat. However, several cultivated S. tabernaemontani strains have recently been introduced. The latter species is often used to stabilize riverbanks. To determine the existing genetic diversity among these species, stems from plants from 44 different locations were subjected to random amplified polymorphic DNA (RAPD) analysis, using 22 decanucleotide primers. Data analysis of the amplified DNA fragments enabled us to unambiguously differentiate among these Scirpus taxa. Hybridization between S. triqueter and S. tabernaemontani was documented, and the studied hybrids were always genetically more similar to S. triqueter than to S. t...

The comet assay: a tool to study alteration of DNA integrity in developing plant leaves

Mechanisms of Ageing and Development, 1999

DNA integrity of Nicotiana tabacum L. and Vicia faba L. leaves in different stages of growth was ... more DNA integrity of Nicotiana tabacum L. and Vicia faba L. leaves in different stages of growth was analysed with the single cell gel electrophoresis (comet) assay. With this test DNA of individual cells is stretched by electrophoresis and the migration is measured, which gives an image of the nuclear DNA organisation. Nuclei were sampled when the plants had developed an apical bud, five true leaves and cotyledons. To get an idea of the kind of lesions observed, three different comet protocols were used. The neutral protocol with electrophoresis in a neutral buffer and the semi-alkaline or alkaline assay with alkaline unwinding followed by electrophoresis in neutral alkaline buffer, respectively. For V. faba there was a successive increased cellular DNA mobility with age of the leaves. The percentage DNA migration in control cells of fully developed leaves from N. tabacum almost reached the same level than after irradiation of not fully developed leaves with 50 Gy X-rays. The increased stretching of DNA with leaf age was most obvious if the DNA duplex was converted to single strands by alkali treatment before electrophoresis. Therefore, it could be concluded that with the ageing of leaves there is a decrease in DNA integrity, which could be the result

Ambrosia maritima: effects on molluscs and non-target organisms

Journal of Ethnopharmacology, 1991

The actual knowledge about Amhrosio nmri/imu is reviewed with emphasis on recent developments in ... more The actual knowledge about Amhrosio nmri/imu is reviewed with emphasis on recent developments in the tields of plant morphology and taxonomy, the molluscicidal principles -the sesquiterpene lactones -present in the plant and the effects on snails and on nontarget organisms, The use of the plant in traditional medicine is also discussed. Areas where more research is needed are outlined.

Effect of Ambrosia maritima on Anopheles stephensi and Aedes aegypti

Journal of Ethnopharmacology, 1994

Reduced reproductive success in small populations of the self-incompatible Primula vulgaris

Journal of Ecology, 2004

1 Habitat fragmentation and the resulting decline in population size can affect biotic interactio... more 1 Habitat fragmentation and the resulting decline in population size can affect biotic interactions and reproductive success of plant species. We investigated the impact of habitat type, population size, morph type and frequency, plant density, floral display and predation on different reproductive components in 16 populations of the distylous self-incompatible perennial herb, Primula vulgaris , a rare, declining species in Belgium. 2 Although habitat type accounted for significant variation in population size, we did not find any relation between habitat type and either reproductive and vegetative characteristics. Population size, however, strongly affected reproductive success, such that plants in small populations produced significantly fewer fruits per plant and seeds per fruit, and therefore fewer seeds per plant. 3 No significant difference was found between morph types for any reproductive characteristic, nor an interaction with population size. However, when morph frequency was strongly biased ( ≥ 1 : 3), the proportion of flowers setting fruit and the number of seeds per fruit were significantly lower in individuals of the common morph type. 4 Within populations, individual plants varied tremendously in size and floral display. Total number of fruits per plant significantly increased with floral display, but the highest fruit set per flower was found at intermediate flower number. 5 The proportion of fruit suffering pre-dispersal predation per plant significantly increased with floral display, but this did not offset the potential fitness gains of producing a large display. Furthermore, the absolute number of predated fruits per plant was significantly and positively affected by the interaction of the total number of fruits per plant and the density of the population.

Experimental evaluation of anaerobic digestion for coffee wastewater treatment and its biomethane recovery potential

International Journal of Environmental Science and Technology, 2013

Epilithic diatoms as indicators in tropical African rivers (Lake Victoria catchment)

Hydrobiologia, 2012

We investigated epilithic diatoms in rivers draining to the Nyanza Bay in Lake Victoria (Kenya) w... more We investigated epilithic diatoms in rivers draining to the Nyanza Bay in Lake Victoria (Kenya) with the aim of determining environmental gradients in the assemblages and testing the usefulness of diatom metrics from temperate regions. Spatial and temporal variations of assemblages were studied in 12 sites of three rivers. Kibos, Nyando, and Kisat rivers contained 224 diatom taxa collected on seven sampling occasions over 4 years. Species richness showed a marginal decrease downstream and was the lowest at sites with high conductivity and ammonia-nitrogen levels. Two-Way Indicator Species Analysis and Canonical Correspondence Analysis revealed two major groups of river sites. Conductivity, alkalinity, turbidity, dissolved oxygen, and silicate were the most important variables influencing species distribution. Ecological diatom metrics of temperate regions and the Specific Pollution sensitivity Index showed good relationships with environmental variables. Both diatom assemblages and averaged indicator values were strong in predicting sites of ecological deterioration and in differentiating an upstream site of better quality (drinking water supply of Kisumu), thereby confirming epilithic diatoms as suitable water quality indicators in equatorial rivers. The use of metrics initially designed for temperate rivers, however, appears less valuable in good quality tropical rivers because potential indicators are not considered.

Biogeographical patterns of Ruppia in the Mediterranean: new insights into diversity and dispersal

International Conference on Mediterranean Temporary Ponds, 2009

Checklist van de Vlaamse vaatplanten 1993: naar een flora - statistiek voor Vlaanderen : een nuttig instrument voor het natuurbehoud

Outbreeding depression and breeding system evolution in small, remnant populations of Primula vulgaris: consequences for genetic rescue

Conservation Genetics, 2017

Many species suffer from anthropogenic habitat fragmentation. The resulting small and isolated po... more Many species suffer from anthropogenic habitat fragmentation. The resulting small and isolated populations are more prone to extinction due to, amongst others, genetic erosion, inbreeding depression and Allee-effects. Genetic rescue can help mitigate such problems, but might result in outbreeding depression. We evaluated offspring fitness after selfing and outcrossing within and among three very small and isolated remnant populations of the heterostylous plant Primula vulgaris. We used greenhouse-grown offspring from these populations to test several fitness components. One population was fixed for the pin-morph, and was outcrossed with another population in the field to obtain seeds. Genetic diversity of parent and offspring populations was studied using microsatellites. Morph and population-specific heterosis, inbreeding and outbreeding depression were observed for fruit and seed set, seed weight and cumulative fitness. Highest fitness was observed in the field-outcrossed F1-population, which also showed outbreeding depression following subsequent between-population (back) crossing. Despite outbreeding depression, fitness was still relatively high. Inbreeding coefficients indicated that the offspring were more inbred than their parent populations. Offspring heterozygosity and inbreeding coefficients correlated with observed fitness. One population is evolving homostyly, showing a thrum morph with an elongated style and high autonomous fruit and seed set. This has important implications for conservation strategies such as genetic rescue, as the mating system will be altered by the introduction of homostyles.

Imbalance of Ecosystem Services of Wetlands and the Perception of the Local Community towards their Restoration and Management in Jimma Highlands, Southwestern Ethiopia

Wetlands, 2016

Wetlands provide vital services for the livelihoods of local peoples; however, the ecological int... more Wetlands provide vital services for the livelihoods of local peoples; however, the ecological integrity of wetlands in Ethiopia has not yet been studied. In this study, we investigated the main ecosystem services of wetlands among different land use types, incorporating local perception toward wetland management. Six wetlands were selected from forested, agricultural and urban areas in the Jimma highlands. A total of 332 local residents within a 5-km radius of each wetland were surveyed. An additional 34 development agents and district and zonal experts were interviewed. The provisioning and cultural services were found to surpass the regulatory and supporting services of wetlands in agricultural and urban land uses compared with wetlands located in the forest. Although most individuals positively viewed wetland regulation and supporting services, the majority of households (66 %) were not interested in conserving wetlands because of small landholdings and the need to meet their livelihoods. Consequently, the vital regulatory and supporting services of impacted agricultural and urban wetlands are gradually becoming limited. Urgent action is, therefore, required to restore and protect these wetlands by promoting alternative livelihoods and improving the agricultural productivity of small landholders.

Chloroplast microsatellite markers reveal Zannichellia haplotypes across Europe using herbarium DNA

Belgian Journal of Botany, May 31, 2007

... Zannichellia palustris subsp. repens Z6 Lith Brabant The Netherlands F 6 Z7 Klejtrup sø Vibor... more

Ontwikkelen van een monitoringsysteem en een beoordelingsmethode voor macrofyten in oppervlaktewateren in Vlaanderen overeenkomstig de Europese Kaderrichtlijn Water

Ontwikkelen van een score of index voor het biologisch kwaliteitselement 'macrofyten' voor de Vla... more Ontwikkelen van een score of index voor het biologisch kwaliteitselement 'macrofyten' voor de Vlaamse rivieren en meren overeenkomstig de Europese Kaderrichtlijn Water. Uittesten van de Europese ontwerphandleiding 'REFCOND' voor dit kwaliteitselement in Vlaanderen (VMM.AMO.KRW.ECO2.2002). Opdrachtgever: Vlaamse Milieumaatschappij (VMM) Opdrachthouder: Instituut voor Natuurbehoud (coördinatie) in samenwerking met Nationale Plantentuin van Meise,

The genus Ruppia L. (Ruppiaceae) in the Mediterranean region: An overview

Aquatic Botany, 2015

This paper reviews the current knowledge on the diversity, distribution and ecology of the genus ... more This paper reviews the current knowledge on the diversity, distribution and ecology of the genus Ruppia L. in the Mediterranean region. The genus Ruppia, a cosmopolitan aquatic plant complex, is generally restricted to shallow waters such as coastal lagoons and brackish habitats characterized by fine sediments and high salinity fluctuations. In these habitats Ruppia meadows play an important structural and functional role. Molecular analyses revealed the presence of 16 haplotypes in the Mediterranean region, one corresponding to Ruppia maritima L., and the others to various morphological forms of Ruppia cirrhosa (Petagna) Grande, all together referred to as the "R. cirrhosa s.l. complex", which also includes Ruppia drepanensis Tineo. Populations of hybrid origin between R. maritima and R. cirrhosa and polyploidy have been detected.

First Record of Najas setacea (A. Br.) Rendle from Continental Africa

Bulletin du Jardin botanique national de Belgique / Bulletin van de National Plantentuin van België, 1988

Isozyme Patterns and Taxonomic Position of a Central African Population of Najas Marina L. Subsp. Armata (Lindb. f.) Horn af Rantzien

Bulletin du Jardin botanique national de Belgique / Bulletin van de National Plantentuin van België, 1985

... In the present paper we consider a population of the African subsp. armata (Lindb. f.) Horn a... more

Monograph of the African Genus Lagarosiphon Harvey (Hydrocharitaceae)

Bulletin du Jardin botanique national de Belgique / Bulletin van de National Plantentuin van België, 1983

... Fl. Afr. 5 : 1 (1894); Wright in This.-Dyer, Fl. Trop Afr. 7 : 4 (1897); Andrews, Flow. Pl. S... more ... Fl. Afr. 5 : 1 (1894); Wright in This.-Dyer, Fl. Trop Afr. 7 : 4 (1897); Andrews, Flow. Pl. Sudan 3: 227 (1956). - Type : Sudan, &amp;lt;&amp;lt; Arasch-Cool ,,, Kotschy 170 (holo-B &amp;#x27;; lecto-G; iso-BM, K, L, MPU, P, Z). - Fig. 5. Udora cordofana Hochst. in sched. pl. exs. Kotschyi, It. Nubic. ...

Genetic differentiation between Bruguiera gymnorhiza and B. sexangula in Sri Lanka

Diversity and Function in Mangrove Ecosystems, 1999

The identification of populations of Bruguiera sexangula, Bruguiera gymnorhiza and their putative... more The identification of populations of Bruguiera sexangula, Bruguiera gymnorhiza and their putative hybrids in the field is difficult using only morphological and phenological characters. Using a PCR based technique, RAPD (Random Amplified Polymorphic DNA), the genetic variation of Bruguiera populations was studied from contrasting climatic and geographic regions along the southwest coastal region of Sri Lanka. Out of 45 primers screened, 20 primers allowed us to observe polymorphism, not only between species (interspecific) but also within the species (intraspecific). Analysis of RAPD data appears to be helpful in determining the genetic relationship among populations of B. gymnorhiza and B. sexangula. RAPD markers revealed that the two species are well separated without any hybrid position between the two taxa though they occur in mixed stands. Although sampling sizes of populations of this study were small, genetic variation among B. gymnorhiza and B. sexangula populations could be observed. For B. sexangula, it was possible to differentiate each of the three populations, even when using a small number of primers.

Strong isolation by distance revealed among Cyperus papyrus populations in the Rift Valley lakes, Lake Victoria, and isolated wetlands of Kenya

Aquatic Botany, 2015

Many aquatic plant populations occur in isolated habitats surrounded by land masses which can act... more Many aquatic plant populations occur in isolated habitats surrounded by land masses which can act as barriers to gene flow, unless other mechanisms exist to facilitate connectivity. This isolation together with life history processes influences greatly genetic diversity and structure among populations of aquatic species. We assessed clonal diversity, genetic variation, and genetic structure of Cyperus papyrus that occur in large geographical scale in freshwater wetlands of Kenya using eight nuclear microsatellite markers. A total of 60 alleles were found across 14 populations. The genetic diversity measures varied widely among populations, with both Lakes Naivasha and Victoria displaying higher allelic and gene diversity than isolated wetlands. C. papyrus maintained relatively high levels of clonal diversity and gene diversity at species level (P P = 79%, A T = 25, H E = 0.41, H O = 0.40) comparable to other clonal aquatic plants. Whereas, two monoclonal wetlands suggested recent founder effects, we attributed variation in clonal diversity to different levels of sexual reproduction and perennation among populations. AMOVA revealed overall high genetic differentiation among populations (F ST = 0.250, p = 0.001) which varied from very low (F ST = 0.014) within lakes to very high (F ST = 0.565) among Lake Victoria-Rift Valley lakes and isolated wetlands. Lack of genetic differentiation among populations within Lakes Victoria and Naivasha implicated hydrochorous dispersal. A Mantel test showed significant isolation-by-distance among populations whereas a PCoA and Bayesian analysis of individuals grouped populations according to drainage basins. We hypothesized that connectivity among distant isolated locations could be by migratory waterfowl or large herbivores (through both endozoochory and epizoochory) and historical inter-basin connection.

Toxicite d'Ambrosia maritima L., plante molluscicide, sur les organismes aquatiques non-cibles

Toxicon, 1991

Toxicité d'Ambrosia maritima L., plante molluscicide, sur les organismes aquatiques non~ibles. To... more Toxicité d'Ambrosia maritima L., plante molluscicide, sur les organismes aquatiques non~ibles. Toxicon 29, 745-750, 1991 .-La toxicité de la plante molluscicide, Ambrosia maritima L., a été testée chez des poissons, des crustacés et des algues. En utilisant la poudre ou un extrait éther-méthanol-hexane des feuilles de la plante, la t' .l . sp pour les alevins de Lebistes reticulatus (guppy) est respectivement 650 et 450 mgJlitre. Ceci est nettement plus élevé qua la concentration molluscicide de 35 à 70 mgflitre utilisée sur le terrain (canaux d'irrigation) en Egypte . Un degré similaire de toxicité a été observé dans des tests préliminaires sur des juveniles de L. reticulates et de Tilapia sures. En utilisant le même extrait d'A . maritima la ~so pour Daphnia magna est de 766 mg/litre et il n'y a pas de toxicité sur l'algue Selenastrum capricornutum à 1 goitre . Ambrosia maritima semble donc avoir une très faible toxicité pour les organismes aquatiques non~ibles. A la dose molluscicide de 35 à 70 mg/litre il n'y a pas d'effets toxiques . F . ALtutn, S. G1~leTS and L. TRII?sT. Toxicity of the molluscicidal plant, Ambrosia maritima L., to aquatic non-target organisms. Toxicon 29, 745-750, 1991 .-The toxicity of the molluscicidal plant, Ambrosia maritirna L., has been evaluated in fish, crustacea and algae. The Lc,~for fries of the guppy, Lebistes reticulates, was respectively 650 and 450 mg/litre using a powder or an ether-methanol-hexane extract from the leaves of the plant. This concentration is much higher than the molluscicidal concentration (LCD of 35 to 70 mg/litre, which is used in the field (irrigation canals in Egypt) . Preliminary tests showed that juveniles of L. reticulates and Tilapia sures were as sensitive as the fries. Using the same extract of A. maritima the Lcm for Daphnia magna was 766 mg/litre and no toxic effects could be observed in algae Selenastrum capricormttum at 1 g,/litre . It can be concluded that A. maritima has a very low toxicity to aquatic non-target organisms. It is not toxic when used at the molluscicidal concentration of 35 to 70 mg/litre.

The use of random amplified polymorphic DNA (RAPD) for hybrid detection in Scirpus from the river Schelde (Belgium)

Molecular Ecology, 1999

Along the unique freshwater tidal zone of the river Schelde (Belgium), plants of Scirpus species ... more Along the unique freshwater tidal zone of the river Schelde (Belgium), plants of Scirpus species occur primarily in small and fragmented populations. The majority of these are native Scirpus lacustris, S. pungens, S. triqueter, S. tabernaemontani and intermediate morphological forms. The distribution area of S. triqueter is even restricted to this tidal habitat. However, several cultivated S. tabernaemontani strains have recently been introduced. The latter species is often used to stabilize riverbanks. To determine the existing genetic diversity among these species, stems from plants from 44 different locations were subjected to random amplified polymorphic DNA (RAPD) analysis, using 22 decanucleotide primers. Data analysis of the amplified DNA fragments enabled us to unambiguously differentiate among these Scirpus taxa. Hybridization between S. triqueter and S. tabernaemontani was documented, and the studied hybrids were always genetically more similar to S. triqueter than to S. t...

The comet assay: a tool to study alteration of DNA integrity in developing plant leaves

Mechanisms of Ageing and Development, 1999

DNA integrity of Nicotiana tabacum L. and Vicia faba L. leaves in different stages of growth was ... more DNA integrity of Nicotiana tabacum L. and Vicia faba L. leaves in different stages of growth was analysed with the single cell gel electrophoresis (comet) assay. With this test DNA of individual cells is stretched by electrophoresis and the migration is measured, which gives an image of the nuclear DNA organisation. Nuclei were sampled when the plants had developed an apical bud, five true leaves and cotyledons. To get an idea of the kind of lesions observed, three different comet protocols were used. The neutral protocol with electrophoresis in a neutral buffer and the semi-alkaline or alkaline assay with alkaline unwinding followed by electrophoresis in neutral alkaline buffer, respectively. For V. faba there was a successive increased cellular DNA mobility with age of the leaves. The percentage DNA migration in control cells of fully developed leaves from N. tabacum almost reached the same level than after irradiation of not fully developed leaves with 50 Gy X-rays. The increased stretching of DNA with leaf age was most obvious if the DNA duplex was converted to single strands by alkali treatment before electrophoresis. Therefore, it could be concluded that with the ageing of leaves there is a decrease in DNA integrity, which could be the result

Ambrosia maritima: effects on molluscs and non-target organisms

Journal of Ethnopharmacology, 1991

The actual knowledge about Amhrosio nmri/imu is reviewed with emphasis on recent developments in ... more The actual knowledge about Amhrosio nmri/imu is reviewed with emphasis on recent developments in the tields of plant morphology and taxonomy, the molluscicidal principles -the sesquiterpene lactones -present in the plant and the effects on snails and on nontarget organisms, The use of the plant in traditional medicine is also discussed. Areas where more research is needed are outlined.

Effect of Ambrosia maritima on Anopheles stephensi and Aedes aegypti

Journal of Ethnopharmacology, 1994

Reduced reproductive success in small populations of the self-incompatible Primula vulgaris

Journal of Ecology, 2004

1 Habitat fragmentation and the resulting decline in population size can affect biotic interactio... more 1 Habitat fragmentation and the resulting decline in population size can affect biotic interactions and reproductive success of plant species. We investigated the impact of habitat type, population size, morph type and frequency, plant density, floral display and predation on different reproductive components in 16 populations of the distylous self-incompatible perennial herb, Primula vulgaris , a rare, declining species in Belgium. 2 Although habitat type accounted for significant variation in population size, we did not find any relation between habitat type and either reproductive and vegetative characteristics. Population size, however, strongly affected reproductive success, such that plants in small populations produced significantly fewer fruits per plant and seeds per fruit, and therefore fewer seeds per plant. 3 No significant difference was found between morph types for any reproductive characteristic, nor an interaction with population size. However, when morph frequency was strongly biased ( ≥ 1 : 3), the proportion of flowers setting fruit and the number of seeds per fruit were significantly lower in individuals of the common morph type. 4 Within populations, individual plants varied tremendously in size and floral display. Total number of fruits per plant significantly increased with floral display, but the highest fruit set per flower was found at intermediate flower number. 5 The proportion of fruit suffering pre-dispersal predation per plant significantly increased with floral display, but this did not offset the potential fitness gains of producing a large display. Furthermore, the absolute number of predated fruits per plant was significantly and positively affected by the interaction of the total number of fruits per plant and the density of the population.

Experimental evaluation of anaerobic digestion for coffee wastewater treatment and its biomethane recovery potential

International Journal of Environmental Science and Technology, 2013

Epilithic diatoms as indicators in tropical African rivers (Lake Victoria catchment)

Hydrobiologia, 2012

We investigated epilithic diatoms in rivers draining to the Nyanza Bay in Lake Victoria (Kenya) w... more We investigated epilithic diatoms in rivers draining to the Nyanza Bay in Lake Victoria (Kenya) with the aim of determining environmental gradients in the assemblages and testing the usefulness of diatom metrics from temperate regions. Spatial and temporal variations of assemblages were studied in 12 sites of three rivers. Kibos, Nyando, and Kisat rivers contained 224 diatom taxa collected on seven sampling occasions over 4 years. Species richness showed a marginal decrease downstream and was the lowest at sites with high conductivity and ammonia-nitrogen levels. Two-Way Indicator Species Analysis and Canonical Correspondence Analysis revealed two major groups of river sites. Conductivity, alkalinity, turbidity, dissolved oxygen, and silicate were the most important variables influencing species distribution. Ecological diatom metrics of temperate regions and the Specific Pollution sensitivity Index showed good relationships with environmental variables. Both diatom assemblages and averaged indicator values were strong in predicting sites of ecological deterioration and in differentiating an upstream site of better quality (drinking water supply of Kisumu), thereby confirming epilithic diatoms as suitable water quality indicators in equatorial rivers. The use of metrics initially designed for temperate rivers, however, appears less valuable in good quality tropical rivers because potential indicators are not considered.