Evaluating Approaches to the Conservation of Rare and Endangered Plants

Schemske, Douglas W.; Husband, Brian C.; Ruckelshaus, Mary; Goodwillie, Carol; Parker, Ingrid M.; Bishop, John G.

doi:10.2307/1941718

Cited by 944 publications

(677 citation statements)

References 108 publications

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“…Artificial fragmentation of Laminaria digitata populations is thus likely to reduce genetic variation in natural populations by rupturing contacts with neighbouring stands. Although the link between reduction in neutral genetic diversity and extinction is debated (Schemske et al 1994), new harvesting practices may lead to the fragmentation of continuous populations beyond demographic sustainability. In the context of possible over-exploitation of L. digitata, the results from our study show that the risk of depletion of genetic variation and extinction should seriously be taken into account by the resource management bodies responsible for the sustainability of this marine algal crop.…”

Section: Implications For the Harvesting Laminaria Digitata Populationsmentioning

confidence: 99%

Current patterns, habitat discontinuities and population genetic structure: the case of the kelp Laminaria digitata in the English Channel

Billot¹,

Engel²,

Rousvoal³

et al. 2003

Mar. Ecol. Prog. Ser.

118

119

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Laminaria digitata is the dominant species of the dense, continuous kelp stands in the English Channel and on the Atlantic coasts of France, where it is harvested for its high quality alginates. However, in spite of its ecological and economic importance, our knowledge of the level and organisation of genetic diversity in this species is scant. Here, using comprehensive hierarchical sampling and 7 microsatellite loci, we explored the roles of dispersal strategies, current regimes and habitat discontinuities in shaping genetic structure of L. digitata populations. Our results show that continuous, non-fragmented forests of L. digitata were genetically differentiated at distances greater than 10 km, despite the absence of clear population boundaries. Furthermore, a pattern of isolationby-distance indicated that gene flow occurred preferentially among adjacent populations following a stepping-stone model. In addition, we analysed the direction of migration using assignment tests and found that currents appeared to play a minor role in orienting gene flow, except in the Gulf of Saint Malo gyre. In contrast, habitat discontinuities were found to accentuate genetic differentiation and resulted in reduced genetic variation of isolated stands. In the context of a potential over-exploitation of kelp stands in Brittany, this study suggests that the existence of neighbouring populations can be vital to maintaining high levels of gene flow and thus, genetic diversity in this species.

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Section: Implications For the Harvesting Laminaria Digitata Populationsmentioning

confidence: 99%

Current patterns, habitat discontinuities and population genetic structure: the case of the kelp Laminaria digitata in the English Channel

Billot¹,

Engel²,

Rousvoal³

et al. 2003

Mar. Ecol. Prog. Ser.

118

119

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“…Globally, many flowering plant species are rare and endangered as a direct result of human pressure on their habitats (Schemske et al 1994). They usually display a limited geographical distribution and occur in small, isolated populations.…”

Section: Introductionmentioning

confidence: 99%

Myophily in the critically endangered umbelliferous plant Ostericum palustre Besser (Apiaceae)

2013

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Globally, many plant species face humaninduced habitat loss and an associated reduction in population size and vitality. Their survival is often possible only when appropriate conservation measures are taken that address the biology and ecology of these species, including their reproduction, often the most vulnerable stage in the life history of the organism. Unfortunately, little is known about these aspects of the biology of many listed plant species. For 3 years, we studied the pollination biology of the critically endangered plant species Ostericum palustre Besser (Apiaceae), one that is listed in the Bern Convention and Annex II of the EU Flora-Fauna Directive. Flowers of this taxon were visited by over 81 species of anthophilous insects derived from 5 taxonomic orders, indicating the presence of a generalised pollination system. However, detailed analyses of the frequency of insect visits, pollen loads and insect behaviour on inflorescences suggest that the plant is chiefly pollinated by large Dipterans, predominantly large Syrphid flies and Muscoid flies, that together are often responsible for over 90 % of total pollinations. Occasionally, wasps (Vespidae) may also be involved in the pollination of this species. With respect to the pollination system of O. palustre, our results indicate that this is a classic example of myophily, and generally, this species can be regarded as a functional specialist, but like many other members of Apiaceae, it is a typical ''bethedger''. This strategy may probably increase the plant's reproductive success in a range of habitat conditions, suggesting that the pollination system is unlikely to be the cause of rarity in this species.

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“…Assim, a fragmentação tornou-se um processo lógico de uso dos recursos naturais por fazendeiros e comunidades locais (VIANA, 1995). Esta questão está evidenciada em diversos estudos sobre os efeitos da fragmentação de ecossistemas (LEVIN & KERSTER, 1974;PLATT & WEISS, 1985;SCHEMSKE et al, 1994e SCARIOT, 1999.…”

Section: Introductionunclassified

“…Alguns trabalhos, dentre eles os de BAWA (1974), JANZEN (1980), CATHARINO et al (1982), CRESTANA et al (1982), BAKER et al (1983), SCHEMSKE et al (1994, BARBOSA (1983), ARROYO & USLAR (1993), ARMSTRONG & MARSH (1997), BARBOSA (1997) e BORGES (2000, abordando aspectos particulares de biologia floral, sistema de cruzamento e interações entre animais e plantas, trouxeram informações muito valiosas, porém, outras pesquisas devem ser efetuadas, pois diversos aspectos ainda não foram estudados, especialmente em ambientes fragmentados.…”

Section: Introductionunclassified

Sistema reprodutivo de Anadenanthera peregrina (L.) Speg e Vochysia haenkiana (Spreng.) Mart. em fragmento de cerrado na Chapada dos Guimarães - MT

2003

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Reprodutive system of Anadenanthera peregrina and Vochysia haenkiana in a fragment of Cerrado forest from Chapada dos Guimarães -MT, Brazil RESUMO O presente estudo objetivou avaliar o sistema reprodutivo das espécies Anadenanthera peregrina (L.) Speg. e Vochysia haenkiana (Spreng.) Mart. Foram estudados aspectos do sistema de cruzamento, complementados pelas observações de maturação dos frutos e a germinação das sementes em função dos tipos de cruzamentos testados. As síndromes de dispersão das sementes foram também avaliadas através das características morfológicas dos frutos e sementes. O estudo foi realizado em um fragmento de cerrado com aproximadamente 32 ha, no município de Chapada dos Guimarães, MT, a 15 0 10 S, 55 0 35 W, e à altitude de 450m. O delineamento experimental utilizado na determinação do sistema de cruzamento para cada espécie foi o de blocos ao acaso, com seis tratamentos para a espécie Vochysia haenkiana e cinco tratamentos para Anadenanthera peregrina, ambas com três repetições. O sistema de cruzamento detectado para as duas espécies foi o preferencialmente alogâmico, porém, com a possibilidade, não desprezível, de produção de frutos/ sementes por autofertilização, sugerindo um aumento gradual de autocompatibilidade genética como estratégia de geração de descendência no ambiente florestal fragmentado. A polinização cruzada em Anadenanthera peregrina é favorecida tanto pelo alto grau de auto-incompatibilidade genética quanto pela protandria detectada. O padrão de maturação dos frutos e sementes e o período de dispersão das sementes foram distintos em ambas as espécies, ocorrendo, entretanto, durante ou no final da estação seca, facilitando a distribuição dos propágulos anemocóricos. A germinação em ambas as espécies foi rápida e em alta percentagem.Palavras-chave: fragmentação florestal, angico branco, cambarazinho.1 Engenheiro Florestal, D.Sc,Universidade Católica Dom Bosco (UCDB), Programa Desenvolvimento Local, CP 100, 79117-900, Campo Grande, MS. E-mail: rcosta@ucdb.br Autor para correspondência. 2 Acadêmicas do Curso de Biologia da Universidade Católica Dom Bosco (UCDB), bolsistas CNPq. ABSTRACTThe study of the breeding system of Anadenanthera peregrina (L.) Speg. and Vochysia haenkiana (Spreng.) Mart. was the main purpose of this work. It was also studied fruit maturation, seed dispersal and seed germination to characterize the reproductive system of these two species. Field work was carried out in a fragment of cerrado forest from Chapada dos Guimarães-MT (15 0 10 S, 55 0 35 W), with an altitude of 450m. Date analyses followed the randomized block design, with. six treatments for Vochysia haenkiana and five treatments for Anadenanthera peregrina, each treatment replicated three individuals. Both species showed a breeding system preferably xenogamic (cross-pollination), but fruit production by autogamy suggests a gradual increase of genetic selfcompatibility as a strategy for maintenance of progeny presence in fragmented forest environment. The degree of genetic selfincompatibility d...

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Evaluating Approaches to the Conservation of Rare and Endangered Plants

Cited by 944 publications

References 108 publications

Current patterns, habitat discontinuities and population genetic structure: the case of the kelp Laminaria digitata in the English Channel

Current patterns, habitat discontinuities and population genetic structure: the case of the kelp Laminaria digitata in the English Channel

Myophily in the critically endangered umbelliferous plant Ostericum palustre Besser (Apiaceae)

Sistema reprodutivo de Anadenanthera peregrina (L.) Speg e Vochysia haenkiana (Spreng.) Mart. em fragmento de cerrado na Chapada dos Guimarães - MT

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