Habitat differentiation in the threatened aquatic plant genus Baldellia (L.) Parl. (Alismataceae): Implications for conservation

A comparative analysis of the habitats of Baldellia ranunculoides (subsp. ranunculoides and subsp. repens) and Baldellia alpestris (Alismataceae) was carried out across central and western Europe. Soil samples from 43 populations were analyzed and the composition of accompanying vegetation was analyzed by canonical correspondence and indicator species analysis. Significant differences in the habitat conditions and the accompanying vegetation were found between the three taxa. B. ranunculoides subsp. repens is growing in lowland water bodies on acidic substrates (pH 5–6.3) which are markedly richer in organic matter and poorer in cations, especially in Ca²⁺. B. ranunculoides s. str. is also a lowland taxon, but grows on more mineral and basic substrates (pH 7–9), usually rich in Ca²⁺. The endemic B. alpestris grows in the most distinct habitats, on substrates with low pH and with very low Ca²⁺ concentrations, at much higher altitudes than the other taxa and in very specific plant communities that have almost no affinities with those of the two lowland Baldellia-taxa. The Baldellia-taxa are threatened by eutrophication of their habitats. Moreover, many of the extant populations, in particular those of B. ranunculoides s. str., are very small and will be threatened by environmental stochasticity. Reintroduction and the creation of new populations might reduce the risk of extinction. Information given on the detailed habitat preferences of the Baldellia-taxa could help conservation efforts for these endangered taxa and identify suitable sites for (re-) introductions.     

Is the global conservation status assessment of a threatened taxon a utopia?

The signatory countries of the Convention on Biological Diversity agreed to significantly reduce the rate of biodiversity loss by 2010. How will we know, however, if we have achieved this goal? Eight groups of hindrances in evaluating the global conservation status of threatened taxon are identified: (1) the extreme heterogeneity and (2) restricted availability of relevant data; (3) the uncertainty in species number and taxonomic division of the given taxon (Linnean shortfall); (4) the fragmentary distribution knowledge (Wallacean shortfall); (5) the incomplete or incorrect red-listing across the whole distribution area; (6) the lack of homogeneous and exhaustive population trend data; (7) the threat knowledge shortfall; (8) the incomplete general biological knowledge on a given taxon. The Linnean and Wallacean shortfalls lay the foundation of all other hindrances. So long as this dramatic shortfall situation does not change, the adequate assessment of the global status for overwhelming majority of extant taxa will remain a utopia.     

Water table and species identity outweigh carbon and nitrogen availability in a softwater plant community

Performance of aquatic macrophytes is driven by many environmental factors, and a major challenge is to understand how aquatic macrophyte communities are structured in various environments. In softwater lakes in Western Europe, hydrological state (submersed/emersed), carbon dioxide and ammonium levels and species interactions are considered as driving forces in structuring amphibious plant communities. In this study we aimed at evaluating the relative importance of these factors for four species in a competitive neighbourhood. Softwater lake habitat was simulated during one growing season in laboratory conditions, mimicking water level fluctuation, photoperiod and temperature. Artificial communities consisted of small populations of four softwater macrophyte species: Luronium natans, Baldellia ranunculoides ssp. repens, Eleocharis multicaulis and Hydrocotyle vulgaris. These communities were subjected to two levels of carbon dioxide and ammonium. Additionally, monocultures of Baldellia and Eleocharis were grown at a higher nutrient level combination in order to measure their competitive response in a community. Time (hydrological state) and species identity turned out to be the only consistently significant factors determining community composition. Plant performance was clearly species-dependent, while carbon dioxide and ammonium did not have major effects. The competitive response was significant in both Eleocharis and Baldellia. Competition intensity was highest in the emersed state. Carbon dioxide had a supplementary effect on the within-species performance in Luronium, Baldellia and Eleocharis, with high carbon dioxide level mainly resulting in more flowers and more stolons. Community outcomes and competitive responses in aquatic macrophytes appear difficult to predict, because of mixed life strategies and morphological and functional plasticity. We conclude that hydrological state was the only important environmental factor. The identity of the species that were present—implying species interactions—largely determined community outcome.     

Morpho-environmental characterization of the genus Baldellia Parl. (Alismataceae) in the Iberian Peninsula,Balearic islands and North Morocco

Abstract

The genus Baldellia Parl. has always been a complex taxon. Three species and three subspecies have been proposed for the Iberian Peninsula. The morphological variation of this genus in the Iberian Peninsula, Balearic islands and northern Morocco, and its thermo-pluviometric and altitudinal correlation are the focus of this contribution. Twenty-eight morphological variables were examined and subjected to a multivariate statistical analysis. The three morphotypes observed (Form 1, which includes B. ranunculoides subsp. repens and B. alpestris; Form 2, which includes B. ranunculoides and Form 3 – for the new combination B. ranunculoides subsp. ranunculoides var. tangerina (Pau) J. Rocha, A. Crespí, M. García-Barriuso, R. Almeida, J. Honrado, comb. nova proposed here for the first time) seem to represent different reproductive strategies. Morphological variables related with the presence or absence of stolons and the architecture of the inflorescence; the size and number of fruits are the most discriminating variables. Form 1 represents the asexual morphotype; Forms 2 and 3 correspond to morphotypes for which sexual reproduction is preferential. The environmental approach revealed that the asexual form (Form 1) grows in temperate, in more humid conditions, and within a broad altitudinal range. In contrast, the two sexual forms are more common in warmer and drier conditions, and occur over a narrower interval of altitudes.     

Conservation of threatened relict trees through living <Emphasis Type="Italic">ex situ</Emphasis> collections: lessons from the global survey of the genus <Emphasis Type="Italic">Zelkova</Emphasis> (Ulmaceae)

Maintaining living ex situ collections is one of the key conservation methods in botanic gardens worldwide. Despite of the existence of many other conservation approaches used nowadays, it offers for many endangered plants an important insurance policy for the future, especially for rare and threatened relict trees. The aim of this research was to investigate the global extent of living ex situ collections, to assess and discuss their viability and inform the development of conservation approaches that respond to latest global conservation challenges. We used as a model taxon the tree genus Zelkova (Ulmaceae). The genus includes six prominent Tertiary relict trees which survived the last glaciation in disjunct and isolated refugial regions. Our comprehensive worldwide survey shows that the majority of botanic institutions with Zelkova collections are in countries with a strong horticultural tradition and not in locations of their origin. More importantly, the acutely threatened Zelkova species are not the most represented in collections, and thus safeguarded through ex situ conservation. Less than 20% of the ex situ collections surveyed contain plant material of known wild provenance while the majority (90%) of collections are generally very small (1–10 trees). Botanic gardens and arboreta particularly in regions where iconic relict trees naturally occur should play a vital role in the conservation of these species. The coordination of conservation efforts between gardens has to be enhanced to prioritise action for the most threatened relict trees. Large scale genetic studies should be undertaken, ideally at genus level, in order to verify or clarify the provenance of ex situ collections of relict trees in cultivation. For the most threatened relict tree genera, well-coordinated specialist groups should be created.     

The Atlantic elements in the Swiss flora: distribution, diversity, and conservation status

The purpose of this study was to examine the composition, distribution, ecology, and conservation status of the Atlantic elements of the Swiss flora. About 195 Atlantic and 80 Mediterranean–Atlantic vascular plant species of the European flora have been used as the basis for our analysis. The complete list of 3,143 taxa has been used as the reference for the Swiss flora. The distributions of the species are illustrated in coincidence maps based on the computer database of the Data Centre of the Swiss Flora in Geneva, Switzerland. Our study demonstrates clearly that the Atlantic flora of Europe requires a new biogeographical appraisal. The Swiss flora comprises 66 Atlantic and Mediterranean–Atlantic taxa, which are taxonomically and ecologically highly diverse. Switzerland contains 44% of all European Sub-Atlantic plants. This confirms the Sub-Atlantic geographical position of Switzerland. Only one Eu-Atlantic species growing in Switzerland, Vicia orobus, can be classified as native with certainty. This species is critically endangered and merits the highest conservation priority. Although a very alpine country, Switzerland has a relatively large number of Mediterranean–Atlantic species. The Atlantic and Mediterranean–Atlantic plants are a very threatened group in Switzerland, with wetland plants the most imperilled ecological group. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Phylogenetics and phylogeography of the monocot genus Baldellia (Alismataceae): Mediterranean refugia, suture zones and implications for conservation

Aquatic plants, and especially the emblematic genus Baldellia (Alismataceae), are among the most threatened organisms, due to unprecedented human-driven habitat destructions. Therefore protection plans are crucially needed and call for thoroughly documenting the genetic diversity and clarifying the taxonomy of this endangered genus. Our sampling included 282 individuals from 42 natural populations and covered the whole geographical range of the genus, across Europe and the Mediterranean. We combined sequencing of nuclear internal transcribed spacer (ITS) and chloroplastic trnL-ndhF regions with amplified fragment length polymorphism (AFLP) genotyping to investigate the Alismataceae phylogeny, and produce a phylogeography of Baldellia. Our phylogeny strongly supported the monophyly of Baldellia and placed it as the sister clade to Luronium and Alisma, therefore excluding, as previously supposed, a close genetic relatedness to the predominantly neotropical genus Echinodorus. The phylogeography of Baldellia outlined patterns consistent with a hypothesis considering glacial refugia located in the Iberian Peninsula and the Italy/Balkan region from which two distinct genetic lineages re-colonized Europe. These two lineages corresponded respectively to Baldellia ranunculoides (Italy/Balkan derived populations) and Baldellia repens (populations recovered from the Iberian Peninsula refuge), therefore supporting differences outlined between the two taxa in previous ecological and morphological studies. These results allowed clarifying taxonomic uncertainties by confirming the genetic distinctness of B. repens according to B. ranunculoides. A third lineage, Baldellia alpestris, originated and remained endemic to the mountainous regions of the Iberian Peninsula. Unexpectedly, B. repens populations collected in northern Africa, appeared to be genetically distinct from their European counterparts, this calls for further investigation to fully address their genetic and conservation status. Finally, we detected a large hybridization zone in northwestern Europe between B. repens and B. ranunculoides. These results were discussed in light of conservation approaches for Baldellia populations.     

Sterile Germination Requirements of Seeds of Some Water Plants

A sterile germination study with seeds of some common phanerogamic water plants showed almost 100 per cent germination for seeds of Alisma plantago–aquatica, Baldellia ranunculoides and Nymphaea alba. Seeds of Potamogeton lucens could be germinated to about 40 per cent, seeds of Polygonum amphibium germinated sporadically while those of Cladium mariscus could not be germinated at all. Freshly harvested seeds of Alisma and Baldellia showed an ability to germinate at both 20°C and 35°C. A stratification period of one month at +4°C gave germination of all species tested, with the exception of Cladium. Potamogeton germinated in light only, the other species both in light and darkness. Treatment times for surface sterilization in disinfectants are given.     

The reproductive biology of the genusBaldellia (Alismataceae)

The reproductive biology of the genusBaldellia was studied under cultivation and in nature.B. ranunculoides subsp.repens is self-incompatible whereasB. ranunculoides subsp.ranunculoides andB. alpestris are self-compatible. Bud-pollination occurs in theB. alpestris. Self-incompatibility correlates with the production of fewer, larger, more showy flowers, higher pollen production (but reduced pollen grain size), fewer carpels and smaller seeds. Resource allocation to sexual reproduction is inversely correlated with the degree of vegetative growth.B. ranunculoides subsp.repens produces more ramets than subsp.ranunculoides, which reproduces mainly by seeds.B. alpestris is intermediate between the two since it is self-compatible, produces fewer, larger seed than subsp.ranunculoides and is also able to propagate by vegetative means.     

Gap analyses to support ex situ conservation of genetic diversity in Magnolia, a flagship group

Worldwide about one third of all plant species is estimated to be threatened with extinction. Plants are generally under-represented in conservation. However, the global strategy for plant conservation (GSPC) sets forth 16 targets to halt the current and continuing loss of plant diversity within a framework for actions at global, regional, national and local levels. Target 8 of the GSPC directs that at least 75 % of threatened plant species be present in ex situ collections by 2020, but this target is far from being met. By analyzing where gaps in ex situ collections and research exist relative to diversity hotspots of threatened species, it is possible to identify and prioritize action. We undertake a gap analysis of ex situ collection needs in the genus Magnolia, a relatively well-known and valuable genus. Results indicate three main areas of biodiversity (China, Vietnam and Colombia) for the endangered Magnolia taxa. The present paper provides a critical overview of recent conservation activities carried out in the genus Magnolia throughout the world, focusing on genetic diversity analyses of the species.     

Ecological differentiation and cladogenesis of Baldellia (L.) Parl. (Alismataceae)

The Iberian Peninsula is home to a large number of endemic species that often show strong genetic subdivisions which indicate possible isolation of populations in the past. Numerous phylogeographic and phylogenetic studies on Iberian flora and fauna have revealed this territory to be the origin of genetic differentiation during the Pleistocene Ice Age. To better understand the influence of Plio-Pleistocene climatic oscillations on the cladogenesis and population structuring of refugial taxa restricted to freshwaters of the Iberian Peninsula, we studied the evolutionary history of the small European genus Baldellia, both from a phylogenetic/phylogeographic perspective and regarding its ecological characteristics. Molecular analyses were based on four plastid regions and nuclear ITS2 ribosomal spacer from individuals belonging to geographically isolated Baldellia populations, while the relationships between climate and Baldellia species distribution was investigated by redundancy analysis applied to the climatic data with the occurrence of Baldellia species as external variables. The absence of a clear phylogenetic signal most likely reflects a common and recent cladogenesis for Baldellia. In contrast, the more rapidly evolving plastid sequences indicate a recent phylogeographic history of refugial repartition and ecological segregation probably occurring during the last glaciation, a scenario well supported by marked differences in species?? ecological preferences and climate analysis.     

Evidence that vulture restaurants increase the local abundance of mammalian carnivores in South Africa

Vulture restaurants are used worldwide as a conservation tool to provide threatened vultures with a source of supplementary carrion free from anthropogenic contaminants such as poisons and veterinary drugs. While the impacts of supplementary feeding sites on ecosystem and scavenging community dynamics have been investigated in Europe, no information is currently available for southern Africa. This study presents evidence that providing supplementary carrion for vultures stimulated an increase in local abundance of two species of mammalian carnivores, the brown hyaena (Hyaena brunnea) and the black‐backed jackal (Canis mesomelas). These findings require that the wider impacts of providing supplementary carrion for conserving threatened species are fully investigated.     

Eutrophication and endangered aquatic plants: an experimental study on <Emphasis Type="Italic">Baldellia</Emphasis> <Emphasis Type="Italic">ranunculoides</Emphasis> (L.) Parl. (Alismataceae)

Anthropogenic enrichment of aquatic ecosystems is an increasingly common phenomenon, resulting from human population growth and the intensification of industrial and agricultural developments. Eutrophication has been considered to be one of the main causes of the decline of many aquatic plants. These observations, however, have rarely been supported by data or explored in detail using an experimental approach. Our experimental study demonstrates, for the first time, a strong direct negative influence of eutrophication on the performance of the endangered aquatic plant Baldellia ranunculoides s.str. (L.) Parl. (Alismataceae). Both morphological and reproductive traits were significantly affected by this phenomenon. Plants growing on eutrophic substrates were much smaller, possessed fewer and smaller leaves, and their biomass was on average half that of plants growing on a mesotrophic substrate. Additionally, plants growing on eutrophic substrates produced fewer inflorescences and flowers, and they had a smaller number of achenes per capitulum. Consequently, they produced only 15% of the seeds produced by plants growing in non-eutrophic conditions. Thus, the chance of long-term subsistence of B. ranunculoides populations in strongly eutrophic habitats will be significantly reduced, and at the same time, the success of any new establishment of viable B. ranunculoides populations in such habitats will be highly restricted. Conservation efforts for B. ranunculoides, either of existing populations or in newly selected re-introduction sites, should start, therefore, with an assessment of the trophic level of those sites. On the other hand, due to its sensitivity to eutrophication, the presence of viable populations of B. ranunculoides can be used as an indicator of valuable aquatic habitats for oligotrophy-dependent organisms.     

Partnering conservation actions. <Emphasis Type="Italic">Inter situ</Emphasis> solutions to recover threatened species in South West Western Australia

South West Western Australia has a rich endemic flora of global significance. The threats facing this floral diversity are increasing in type, severity and scale, demonstrated by the rising numbers of species threatened with extinction. In particular, the root-rot pathogen Phytophthora cinnamomi is causing widespread destruction, threatening the survival of many of the region’s unique plants. In situ conservation of wild plants is considered the most essential component of a flora conservation program, but the ability to conserve some species adequately is often unachievable in the short term and urgent management intervention is required to prevent extinction. We present data on the status and management of wild populations of four threatened species from the region, including an ex situ program, and describe our efforts to bridge the gap between these two components. Such inter situ conservation recovery work enables monitoring of biological attributes, research into reproductive biology and collection of genetic material for further ex situ conservation, and provides the source of material for future restoration of wild populations.     

Patterns and traits of the endemic plants of Greece

Greece is characterized by high plant diversity (5800 species) and endemism (15.6%). This study attempts a first overall assessment of the taxonomy, distribution, traits and conservation status of the Greek endemic plants. The endemic species belong to 56 families and 242 genera. Most of the endemic plants have a narrow geographical and altitudinal distribution range. The southern floristic regions are richer in endemic species. The species area relationships for endemics (EARs) for island and continental floristic regions explain over 50% of the variation in number of species and are characterized by steep curves. Analysis of the distributional pattern of the endemics by similarity coefficients offers useful insights into the palaeogeography and biogeography of Greece. The endemic species occur at all altitudes, but the altitudinal distribution shows a predominance of local endemics at 0–600 m in the island regions and in higher zones in the continental regions. The life form spectra show a predominance of hemicryptophytes and chamaephytes. This trait seems indicative of their habitat and adaptive strategy and may be related to speciation processes. The overview of the conservation status of the Greek endemics indicates that over 40% of the taxa are threatened or near threatened. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162 , 130–422.     

Biodiversity Conservation of the Genus <Emphasis Type="Italic">Incarvillea</Emphasis> Juss. (Bignoniaceae) Based on Molecular Diversity and Species Richness Assessment

Incarvillea is a genus with considerable ornamental and medicinal value, yet many of its 16 species are threatened in the wild and two (Incarvillea forrestii and Incarvillea altissima) may be extinct. An extensive field survey of the Chinese species has shown that logging is the greatest threat to woodland margin species, while overgrazing by cattle endangers species from alpine meadows. To aid the setting of conservation priorities, we used phylogenetic weighting of species, based on the molecular phylogeny of both nuclear (nrITS) and chloroplast (trnL-F region) gene regions. We estimated molecular diversity with measures for genetic diversity (GD) and phylogenetic diversity (PD). PD/GD values highlighted the importance of Incarvillea sinensis and two Central Asian species, Incarvillea semiretschenskia and Incarvillea olgae from Kazakstan and Kirghizia, for which little is known. This combination of phylogenetic and complementarity analyses focused on the provinces of Sichuan, Yunnan, and Qinghai, with Yunnan having the only adequately protected areas for that genus.     

Island area,body size and demographic history shape genomic diversity in Darwin's finches and related tanagers

Genomic diversity is the evolutionary foundation for adaptation to environmental change and thus is essential to consider in conservation planning. Island species are ideal for investigating the evolutionary drivers of genomic diversity, in part because of the potential for biological replicates. Here, we use genome data from 180 individuals spread among 27 island populations from 17 avian species to study the effects of island area, body size, demographic history and conservation status on contemporary genomic diversity. Our study expands earlier work on a small number of neutral loci to the entire genome and from a few species to many. We find significant positive correlation between island size and genomic diversity, a significant negative correlation between body size and genomic diversity, and that historical population declines significantly reduced contemporary genomic diversity. Our study shows that island size is the key factor in determining genomic diversity, indicating that habitat conservation is key to maintaining adaptive potential in the face of global environmental change. We found that threatened species generally had a significantly smaller values of Watterson's theta (θ_W = 4N_eμ) compared to nonthreatened species, suggesting that θ_W may be useful as a conservation indicator for at‐risk species. Overall, these findings (a) provide biological insights into how genomic diversity scales with ecological, morphological and demographic factors; and (b) illustrate how population genomic data can be leveraged to better inform conservation efforts.     

Extinction Risks and the Conservation of Madagascar's Reptiles

Background

An understanding of the conservation status of Madagascar''s endemic reptile species is needed to underpin conservation planning and priority setting in this global biodiversity hotspot, and to complement existing information on the island''s mammals, birds and amphibians. We report here on the first systematic assessment of the extinction risk of endemic and native non-marine Malagasy snakes, lizards, turtles and tortoises.

Methodology/Principal Findings

Species range maps from The IUCN Red List of Threatened Species were analysed to determine patterns in the distribution of threatened reptile species. These data, in addition to information on threats, were used to identify priority areas and actions for conservation. Thirty-nine percent of the data-sufficient Malagasy reptiles in our analyses are threatened with extinction. Areas in the north, west and south-east were identified as having more threatened species than expected and are therefore conservation priorities. Habitat degradation caused by wood harvesting and non-timber crops was the most pervasive threat. The direct removal of reptiles for international trade and human consumption threatened relatively few species, but were the primary threats for tortoises. Nine threatened reptile species are endemic to recently created protected areas.

Conclusions/Significance

With a few alarming exceptions, the threatened endemic reptiles of Madagascar occur within the national network of protected areas, including some taxa that are only found in new protected areas. Threats to these species, however, operate inside and outside protected area boundaries. This analysis has identified priority sites for reptile conservation and completes the conservation assessment of terrestrial vertebrates in Madagascar which will facilitate conservation planning, monitoring and wise-decision making. In sharp contrast with the amphibians, there is significant reptile diversity and regional endemism in the southern and western regions of Madagascar and this study highlights the importance of these arid regions to conserving the island''s biodiversity.     

Extinction threat to neglected Plinia edulis exacerbated by climate change,yet likely mitigated by conservation through sustainable use

Forecasting the impacts of climate change on species distribution has several implications for conservation. Plinia edulis is a rare and threatened tree species from Brazilian Atlantic Rainforest. In this study, we assessed the impact of global climate change on the distribution of P. edulis. Additionally, we evaluated the efficacy of the Brazilian protected network to conserve this species. Ecological niche models were built using the maximum entropy method based on occurrence records and environmental predictors. Models predicted a reduction of climatically suitable areas for P. edulis in all evaluated scenarios in the coming years. Furthermore, we observed that Brazilian protected areas (PAs) are ineffective to conserve this species. Given the fact that P. edulis is a promising tree species rarely found within Brazilian PAs and threatened by global climate change, we strongly recommend the cultivation of this multipurpose species in agroforestry systems, landscaping and homegardens in order to promote its conservation through sustainable use.     

A comparative analysis of global, national, and state red lists for threatened amphibians in Brazil

The knowledge about the conservation status of species is an important data for conservation biology. Therefore, threatened species lists are a powerful tool for conservation planning and prioritization. Our objective is to compare the global, the national and state red lists of amphibians in Brazil. Threatened species were categorized according to their listing in one or several of these lists. We analyzed for true inconsistencies across lists in order to evaluate practical consequences of such incongruences on amphibian conservation in Brazil. We recorded a total of 61 threatened amphibian species in Brazil (across all red lists). Only one species, Phrynomedusa fimbriata, was listed as Extinct (both in IUCN, Brazil and S?o Paulo lists). A total of eleven endemic species are listed as threatened by the global red list, but do not appear in Brazil’s national red list, which represent an inconsistence among these lists. Besides that, the threat category of Thoropa lutzi and Thoropa petropolitana, two endemic species, differ among both lists, which also represents a problem between both lists. These mismatches may be due to several reasons such as different interpretation of the criteria; different methodologies used; different data availability on species; differences in the dates of assessments processes; the assessors’ attitudes to uncertainty; outdated red lists. Harmonization among red lists permits a better picture of threatened amphibian diversity across scales and to develop global, national and state plans to complement conservation actions in order to maximize the chance of success of these initiatives.