Dune Habitats Research Articles

EU habitats of interest: an insight into Atlantic and Mediterranean beach and foredunes

We compared the Atlantic and Mediterranean beach and foredune habitats of European interest, focusing on floristic, structural and ecological features. We selected two representative sites of Atlantic (The Netherlands) and Mediterranean (Italy) coastal dunes. From a georeferenced vegetation database, samples of: (a) annual vegetation on drift lines (European Union habitat type 1210), (b) embryonic shifting dunes (2110), and (c) shifting dunes along the shoreline with Ammophila arenaria (2120), were selected. Floristic representativity and comparability of plot sizes were considered. For each habitat, the frequency and the fidelity of the species, the life form frequency spectra and Ellenberg ecological indicator values were assessed. We found a consistent floristic differentiation between the Atlantic and the Mediterranean coastal dune habitats and only a small set of shared species. The Italian and the Dutch annual vegetation of drift lines (1210) register a high structural similarity that strongly declines landwards. Floristic composition, life forms and Ellenberg indicator values show higher similarities among different foredune habitats of the same site than between homologous habitats of the Mediterranean and Atlantic coasts. The results confirm the current description and distribution of the habitat of European interest annual vegetation of drift lines (1210). On the other hand, the floristic, structural and ecological differences between the Atlantic and the Mediterranean embryonic shifting dunes (2110) and shifting dunes along the shoreline with Ammophila arenaria (2120) point at an inconsistency of the existing description of those habitats of European interest and highlight the need of adding in the Directive specific types that describe them in the Mediterranean basin. We suggest the introduction of two new habitat types named “Dunes along the Mediterranean shoreline with Ammophila arenaria” (new code 2280) and “Mediterranean embryonic dunes” (new code 2290) within the existing class “Sea dunes of the Mediterranean coast” (class 22 of the Annex I Habitats Directive 92/43/CEE).

Polyploidy and ecological adaptation in wild yarrow.

Chromosome evolution in flowering plants is often punctuated by polyploidy, genome duplication events that fundamentally alter DNA content, chromosome number, and gene dosage. Polyploidy confers postzygotic reproductive isolation and is thought to drive ecological divergence and range expansion. The adaptive value of polyploidy, however, remains uncertain; ecologists have traditionally relied on observational methods that cannot distinguish effects of polyploidy per se from genic differences that accumulate after genome duplication. Here I use an experimental approach to test how polyploidy mediates ecological divergence in Achillea borealis (Asteraceae), a widespread tetraploid plant with localized hexaploid populations. In coastal California, tetraploids and hexaploids occupy mesic grassland and xeric dune habitats, respectively. Using field transplant experiments with wild-collected plants, I show that hexaploids have a fivefold fitness advantage over tetraploids in dune habitats. Parallel experiments with neohexaploids--first-generation mutants screened from a tetraploid genetic background--reveal that a 70% fitness advantage is achieved via genome duplication per se. These results suggest that genome duplication transforms features of A. borealis in a manner that confers adaptation to a novel environment.

Coastal dune systems and disturbance factors: monitoring and analysis in central Italy

This study describes the conservation status of dune systems in relation to disturbance factors in the coastal stretch of the Viterbo province, Latium Region, Italy. Particular emphasis was given to the bioindication value of plant communities and their sequence. Each plant community was considered as a "habitat" in accordance with Annex I of the Directive 92/43/EU. Stress factors, such as sand dynamic and erosion, and anthropogenic pressures, such as trampling and bathing settlements, influence the sequence of habitats and weaken the system of relations that makes these coenoses to occur in extreme conditions. The choice to carry out surveys along wide transects, recording different data, allowed to explore the use of habitats as bioindicators. Comparing sites characterized by the same extension in a homogeneous area, it was possible to expand the use of canonical correspondence analysis (CCA) as a tool to correlate habitat composition and disturbance factors. The application of CCA showed a high correlation of degradation and habitat loss with coastal erosion, trampling and presence of waste. Furthermore, floristic surveys allowed the application of different biodiversity indices to quantify species richness of sampled areas. The conservation status of the sites investigated was found to be diverse, from the total disappearance of the mobile dune habitats to their complete sequence. The proposed methodology has been useful to fulfill the objective of the work and is applicable to other case studies in the Mediterranean.

Greenhouse inoculation of psammophilic plant species with arbuscular mycorrhizal fungi to improve survival and early growth

Psammophilic plants are characterized for their adaptability to the hard environmental conditions of the coastal sand dune habitats that limit the survival of most vegetation. Considering that mycorrhizal plants are known to be effective colonizers of degraded habitats, the influence of the arbuscular mycorrhizal (AM) symbiosis in plant growth was studied in fifteen psammophilic plant species: Lotus creticus, Dorycnium pentaphyllum, Otanthus maritimus, Thymbra capitata, Armeria maritima, Halimium halimifolium, Ononis natrix, Medicago marina, Genista umbellata, Crucinella maritima, Elymus farctus, Ammophila arenaria, Pancratium maritimum, Glaucium flavum and Limoniastrum monopetalum. Wild seeds were used in this study to compare the effect of plant inoculation with a consortium of native AM fungi isolated from a coastal sand dune and with the selected isolate Glomus intraradices BEG 72 versus non mycorrhizal plants. After six months growth, we found that eleven of the fifteen psammophilic species responded positively to AM fungi inoculation and both root and shoot development benefited considerably from the presence of the AM fungi. We can conclude that many of the psammophilic species produced after the germination of the wild seeds collected in their natural habitats show limited growth due in part to the lack of adequate AM fungal inoculum in the plants growing substrate. AM inoculation seems to be critical for their survival.

Native herbivores and plant facilitation mediate the performance and distribution of an invasive exotic grass

Summary1. Exotic plant species have become increasingly prominent features of ecological landscapes throughout the world, and their interactions with native and exotic taxa in these novel environments may play critical roles in mediating the dynamics of such invasions.2. Here, we summarize results from comparative and experimental studies that explore the effects of two factors – herbivory and facilitation – on the performance and distribution of an invasive South African grass,Ehrharta calycina, in a coastal foredune system in northern California, USA.3. Using a 2‐year exclosure experiment, we show that a native herbivore, black‐tailed jackrabbits (Lepus californicus), significantly reduced the height, shoot production, fecundity and above‐ground biomass of this exotic grass.4. Data from two comparative studies and a neighbour‐removal experiment revealed thatEhrhartafrequently escaped herbivores by associating with three neighbouring plant species – an exotic perennial grass,Ammophila arenaria, an exotic perennial succulent,Carpobrotus edulis, and a native perennial shrub,Baccharis pilularis.Ehrhartagrowing in association with neighbours was taller, had fewer grazed shoots, produced greater numbers of spikelets and had greater above‐ground biomass than unassociated individuals. Furthermore, removing neighbours generally eliminated these benefits in 7 months, although effects differed among neighbour species.5. An additional neighbour‐removal experiment conducted in the absence of jackrabbits indicated that neighbour removals did not have significant impacts onEhrhartaheight, shoot production, spikelet production or above‐ground dry biomass. These results suggest that the primary means by whichEhrhartabenefits from neighbouring plants is protection from herbivores – either because they are less apparent to herbivores or less accessible – and thatEhrhartalikely incurred minimal costs from associating with neighbours.6. Ehrhartawas more frequently associated with neighbours than expected due to chance, and less frequently found in open dune habitat. These results are consistent with the hypothesis that the effects of herbivory and facilitation have been sufficiently strong to shape the local distribution of this invader in the landscape.7. Synthesis. Our research has demonstrated that herbivory and facilitation have jointly influenced the dynamics of a biological invasion, and highlights the importance of evaluating the effects of multiple interactions on invasions in a single system.

Pattern of plasticity to irradiance levels and genotypic correlations between structural and physiological leaf traits in Iris pumila

Plasticity to irradiance and genotypic correlations between structural and physiological leaf traits in Iris pumila were investigated in an experiment conducted at a sun-exposed dune habitat in the Deliblato Sands. A sample of six native, genetically different clones were covered with a neutral screen which transmitted ~35% of daylight, so that one clone-half of each clone experienced reduced sunlight, while the other one full sunlight. LMA, stomatal density, ?leaf, enzymatic and non-enzymatic antioxidants and lipid peroxidation were determined in unshaded and shaded leaves of the same clone. It was found that the plasticity index, PIv was higher for physiological than for structural traits. Genotypic correlations between trait pairs were high, but rarely significant, in contrast to the correlation matrices which were significantly different between unshaded and shaded leaves.

Environmental differences in substrate mechanics do not affect sprinting performance in sand lizards (Uma scoparia and Callisaurus draconoides)

Running performance depends on a mechanical interaction between the feet of an animal and the substrate. This interaction may differ between two species of sand lizard from the Mojave Desert that have different locomotor morphologies and habitat distributions. Uma scorparia possesses toe fringes and inhabits dunes, whereas the closely related Callisaurus draconoides lacks fringes and is found on dune and wash habitats. The present study evaluated whether these distribution patterns are related to differential locomotor performance on the fine sand of the dunes and the course sand of the wash habitat. We measured the kinematics of sprinting and characterized differences in grain size distribution and surface strength of the soil in both habitats. Although wash sand had a surface strength (15.4±6.2 kPa) that was more than three times that of dune sand (4.7±2.1 kPa), both species ran with similar sprinting performance on the two types of soil. The broadly distributed C. draconoides ran with a slightly (22%) faster maximum speed (2.2±0.2 m s(-1)) than the dune-dwelling U. scorparia (1.8±0.2 m s(-1)) on dune sand, but not on wash sand. Furthermore, there were no significant differences in maximum acceleration or the time to attain maximum speed between species or between substrates. These results suggest that differences in habitat distribution between these species are not related to locomotor performance and that sprinting ability is dominated neither by environmental differences in substrate nor the presence of toe fringes.

Playing dead to stay alive: death-feigning in Liolaemus occipitalis (Squamata: Liolaemidae)

Predation is the major selective force that drives the development of a series of defense mechanisms by the species. These mechanisms are efficient in that it limits the ability of predators to detect, recognize and subdue their prey. In lizards for example, the tail loss and locomotor escape are the most common defensive behavior reported on the literature. Additionally, in response to external stimuli, some lizards exhibit a peculiar defensive behavior: death-feigning or thanatosis. Here we describe the first record of death-feigning in a population of Liolaemus occipitalis in a coastal sand dune habitat in Southernmost Brazil. A total of 86 individuals were tested. During handling 75.6% of lizards feigned death. The duration of this behavior was longer when the observer remained closer to the lizards, suggesting the ability of L. occipitalis to evaluate the predation risk.

Plant species diversity and genetic diversity interactively influence community properties and ecosystem processes

Abstract Background/Questions/Methods: Biodiversity is a critical element of community properties and ecosystem processes. Both plant species richness and genetic diversity positively affect processes ranging from primary production, ecosystem stability, and the maintenance of diversity. In nature, it is likely that species diversity and genetic diversity interactively affect how communities are structured and ecosystems function. However, the relative contribution of species diversity and genetic diversity to ecological processes has been rarely documented, and potential interactions between the two levels of diversity have not been investigated. Here, I report results from a common garden experiment conducted in a coastal freshwater dune habitat at Sleeping Bear Dunes National Lakeshore in Empire, MI. I manipulated plant species diversity (0, 1, 3, or 6 species) and genetic diversity (0, 1, 3, or 6 populations) within a dominant, dune-building species (Ammophila breviligulata) to address how both levels of diversity simultaneously influence ecological properties and processes. Results/Conclusions: In 2008, plant diversity influenced a wide range of ecological responses. Plant species diversity and genetic diversity within the dominant species synergistically increased above-ground biomass production, with biomass increasing the most with genetic diversity when there were 6 plant species present. A similar pattern was found for arthropod morphospecies richness and abundance. Separately, neither species diversity nor genetic diversity affected either biomass production or the arthropod community. Plant diversity also influenced below-ground properties and processes. For example, nematode abundance doubled with both increasing species diversity and genetic diversity, but there was no interaction between the two levels of diversity. These results suggest that interactions between levels of diversity are an important, but often overlooked, aspect of how diversity structures communities and mediates ecosystem processes and suggests that increasing awareness of these interactions may inform conservation and restoration strategies.

Decadal Changes in Habitat-Type Coverage on Horn Island, Mississippi, U.S.A.

Barrier island geomorphic features change over relatively brief timescales in response to the combined effects of wind, waves, currents, sediment supply, coastal subsidence, sea-level rise, and tropical cyclones. Consequently, alterations in the vegetation composition occur with these physiographic changes. A greater understanding of the extent to which such changes have occurred in recent decades may indicate the likely response of barrier islands to the currently anticipated acceleration in sea-level rise and increase in tropical storm frequency and severity under a climate-warming scenario. Using ground data in conjunction with hyperspectral, Light Detection and Ranging (LIDAR), and historical data, this study classified and mapped vegetation on Horn Island, Mississippi, and compared the island land area and habitat-type distribution in 2004 vs. 1978. Total vegetation cover as a percentage of total land area remained virtually unchanged during the 1978–2004 period. However, the relative coverage of wetland habitat types increased, whereas coverage of drier habitat types declined from 1978 to 2004, suggesting an overall modification of island communities in response to relative sea-level rise, storm events, and reduced sediment availability. A noticeable portion of the loss of drier woodland and stable dune habitats was a consequence of changes in land area and elevation on the eastern end of the island.

The mite (Arachnida: Acari) fauna inhabiting Irish machair: a European Union priority coastal habitat

Machair is a highly specialised and complex sand dune habitat confined globally to the west coasts of Ireland and Scotland. Irish machair is designated as a priority habitat under the EU Habitats Directive, with the habitat coverage restricted to the machair grassland. The main goals of the study were to describe the Acari fauna inhabiting the Irish machair and to determine the uniqueness of its mite communities in the context of habitat protection. Ten Irish machair sites were selected and samples were taken from the machair grassland and from two types of dunes within the wider machair system: shifting dunes (foredunes) occurring at the beach and stable (fixed) dunes located in the transition zone to the inland grassland flat areas. One hundred and eleven mite taxa were recovered. The most widespread was Scutovertex cf arenocolus Pfingstl et al. 2009, a halophilous species that has been found in the epilittoral zone of Baltic and European Atlantic coasts. The genus Autogneta Hull 1916 (Oribatida: Oppiidae) and the oribatid species Hermaniella granulata (Nicolet 1855) were recorded for the first time for Ireland. Peloptulus cf gibbus Mihelcic 1957, may also be a new record. Multivariate analysis showed that community composition varied between the areas sampled in the machair systems and that in the machair grassland, an Annex I priority habitat in Ireland, was especially different from both dune types sampled. The assemblages also varied significantly between the different sites sampled in the study.

Morpho-functional adaptations inCakile maritimaScop. subsp.maritima: comparation of two different morphological types

Along the Italian maritime foredunes there are two different morphotypes of Cakile maritima Scop. subsp. maritima differing in leaf shape: one type is characterized by entire lamina, while the other one shows pinnatifi d leaves. Therefore, this study was performed to analyze leaf morpho-functional characters of both C. maritima morphotypes in order to highlight the peculiar adaptations to the ecological conditions of sand dune environments and to compare the two different morphological types. The morpho-functional traits analyzed are leaf roll, general morphology of epidermis, vesicular cells, salt crys- tals, stomatal apparatus, stomatal density (SD), hydathodes, mesophyll, idioblasts, specifi c leaf area (SLA) and leaf dry matter content (LDMC). The most interesting anatomical adaptations to sand dune habitats are thick epidermal cuticle; high stomatal density; epidermal vesicular cells involved in water storage, sunlight refl exion and together with hydathodes in salt elimination; high development of palisade and water storage parenchyma; bundle sheath typical of C 4 leaf anatomy. Differences in several leaf characters between the two morphotypes seem to suggest that pinnatifi d morphotype is more resistant to stress and environmental disturbance than the entire type. The analysis of C. maritima distribution in two different coastal traits affected by progradation or erosional processes confi rmed this hypothesis.

Species list and habitat preference of Mesostigmata mites (Acari, Parasitiformes) in Latvia

This paper provides a review of the Mesostigmata mite material collected from 1992 up to 2009 in Latvia in a wide range of habitats: dead wood, Aphyllophorales fungi, forests, meadows, dune habitats, agricultural habitats, bogs, epiphytic mosses, and mites associated with Insecta and Vertebrata. A list of 368 Mesostigmata species of 27 families in Latvia with occurrence in different habitats is provided, which can be used as a future reference. According to occurrence among the habitats, the species are classified as generalist species, habitat specialist species or other species. About half of the species recorded were found to be specialist for a given habitat type. The highest proportion of habitat specialist species was found associated with the Vertebrata habitat. In total 39 species were recorded as generalist species; of them two (Parasitus kraepelini and Eviphis ostrinus) were recorded in 8 of the 10 habitat types. The highest number of generalist species was recorded in the Parasitidae (11 species), Aceosejidae (7 species) and Laelaptidae (5 species). Variation of the numbers of habitat specialist species within families among respective habitats was observed. Rhodacaridae and Laelaptidae had high number of specialist species in some habitat types. In total 32 rare species were recorded.

Ecological Assessment of Dune Restorations in the Great Lakes Region

Because of the economic and environmental importance of stabilizing fragile sand dune habitats, restoration of dunes has become a common practice. Restoration efforts in the Great Lakes and East Coast regions of North America often consist of planting monocultures of the dominant native grass species, Ammophila breviligulata. We evaluated 18 dune restoration projects in the Great Lakes region conducted over the past 25 years. We characterized attributes of diversity (plants and insects), vegetation structure (plant biomass and cover), and ecological processes (soil nutrients and mycorrhizal fungi abundance) in each restoration, and we compared these measures to geographically paired natural dune communities. Restoration sites were similar to reference sites in most measured variables. Differences between restorations and reference sites were mostly explained by differences in ages, with the younger sites supporting slightly lower plant diversity and mycorrhizal spore abundance than older sites. Plant community composition varied little between restored and reference sites, with only one native forb species, Artemisia campestris, occurring significantly more often in reference sites than restored sites. Although it remains unclear whether more diverse restoration plantings could accelerate convergence on the ecological conditions of reference dunes, in general, traditional restoration efforts involving monoculture plantings of A. breviligulata in Great Lakes sand dunes appear to achieve ecological conditions found in reference dunes.

Distance Sampling Underestimates Population Densities of Dune-Dwelling Lizards

Distance sampling methods to estimate population densities are in wide use; however, this method may not be suitable for certain species or in certain habitats. Although validation of population estimates derived from distance sampling is necessary to determine the reliability of population estimates, validation is lacking in most studies. We measured densities of six lizard species, with particular emphasis on the endemic Dunes Sagebrush Lizard (Sceloporus arenicolus) at 14 sites throughout the range of this species in the Mescalero Sands ecosystem in southeastern New Mexico. We tested the accuracy of distance sampling by comparing results from 238 distance line transects to densities measured in 20 total removal plots. Density estimates from the distance sampling method (N= 238 transects) for S. arenicolus and all lizard species combined were 4.6 lizards/ha and 26.14 lizards/ha, respectively. Density estimates from the total removal plots (N = 20) were 30.0 lizards/ha for S. arenicolus and 85.0 lizards/ha for all lizard species combined. It is clear that, even in the relatively open shinnery oak sand dune habitat, distance sampling methods were not reliable and underestimated the densities of lizards. The disparity in density estimates from distance sampling versus total removal plots was caused by violation of the assumption of perfect detection of individuals on the transect line. Individuals that were unavailable for detection greatly influenced the density estimates. Because of the difficulty in correcting for biases, we suggest that distance sampling is not an appropriate sampling method for estimating densities of lizards.

Assessing critical habitat: Evaluating the relative contribution of habitats to population persistence

A principal challenge of species conservation is to identify the specific habitats that are essential for long-term persistence or recovery of imperiled species. However, many commonly used approaches to identify important habitats do not provide direct insight into the contribution of those habitats to population persistence. To assess how habitats contribute to overall population viability and characterize their relative importance, a spatially-explicit population viability model was used to integrate a species occurrence model with habitat quality and demographic information to simulate the population dynamics of the Ord’s kangaroo rat ( Dipodomys ordii) in Alberta, Canada. Long-term productivity (births–deaths) in each patch was simulated and iterative patch removal experiments were conducted to generate estimates of the relative contribution of habitat types to overall population viability. Our results indicated that natural dune habitats are crucial for population viability, while disturbed/human-created habitats make a minor contribution to population persistence. The results also suggest that the habitats currently available to Ord’s kangaroo rats in Alberta are unlikely to support long-term persistence. Our approach was useful for identifying habitats that did not contribute to population viability. A large proportion of habitat (39%) represented sinks and their removal increased estimated population viability. The integration of population dynamics with habitat quality and occurrence data can be invaluable when assessing critical habitat, particularly in regions with variable habitat quality. Approaches that do not incorporate population dynamics may undermine conservation efforts by under- or over-estimating the value of habitats, erroneously protecting sink habitats, or failing to prioritize key source habitats.

A Modified Track Tube for Detecting Beach Mice

ABSTRACT Standard track tube designs are ineffective for long‐term monitoring of beach mice (Peromyscus polionotus) largely because of blowing sand and rain in the coastal dune habitat. We developed a novel track tube design with the tube elevated, capped on one end, and covered on the other end with a short 90° elbow tube. We tested this tube design against 2 other designs (elevated and ground). Our elevated 90° elbow track tubes detected beach mouse tracks more often and they were disturbed less frequently than elevated or ground tubes. Elevated 90° elbow track tubes are a practical means for managers to conduct long‐term monitoring of beach mouse populations.

Ethnomedicinal and ethnoecological evaluation of Salvadora persica L.: A threatened medicinal plant in Arabian Peninsula

An ethno-medicinal survey was conducted in various parts of desert and semi desert ecosystem in Saudi Arabia with the aim to document ethnecological and medicinal value of Salvadora persica. It has been used by Muslim communities since centuries in traditional system of medicine. It remained a source of income and it is believed to be a type of religious toothbrush plant. The folklore uses, indigenous knowledge of local people, and traditional healers regarding S. persica were collected by using standard protocol. Based on the results obtained, it was concluded that S. persica is a multipurpose plant. It is one of the commonly used plants for medicinal purposes as well as due to its ethno-ecological importance. Various parts of S. persica are used as: food, fruits, fodder, a source of lipids, gum and resins. In addition, it is also used as a honey bee rearing plant. Its root is regularly used as tooth brush throughout the country. During the current study, it was also noticed that S. persica is a service provider plant which is grown to provide shelter-belts and windbreaker for agriculture crops. It helps in reclamation of sand dune habitat and saline soil in arid ecosystem of Saudi Arabia. S. Persica is distributed throughout the arid and semi arid ecosystem of Saudi Arabia. However, its population suffers from serious environmental problems such as deforestation, soil degradation, loss of biodiversity and unsustainable livelihoods. The study concluded that S. persicahas high medicinal, economic and ecological values in arid and semiarid ecosystem of Saudi Arabia. Nevertheless, its conservation status is highly threatened and detailed ecological study of S. persica is suggested to conserve its remaining population in Saudi Arabia. Key words: Salvadora persica, medicinal uses, products, threats and conservation importance.

Selecting a Hiding Place: Anuran Diversity and the use of Bromeliads in a Threatened Coastal Sand Dune Habitat in Brazil

Among vertebrates, anuran amphibians represent the highest number of species associated with bromeliads and possess a range of ecological, behavioral, and morphological specializations to life in these plants. Despite the importance of bromeliads as biodiversity amplifiers, and their diversity in some habitats, studies of the relationship between anurans and these plants are scarce in Brazil. Here, we investigated the way anurans select and use bromeliads in a threatened coastal habitat. We analyzed data from 23 standardized samples of the anurans associated with the bromeliad Neoregelia cruenta in the Restinga de Marica, State of Rio de Janeiro, Southeastern Brazil. We found nine anuran species using these bromeliads, representing the highest richness reported for a Brazilian restinga. We identified a general pattern of bromeliad usage, where plants located at the edges of scrub patches (exposed to the sun) were more frequently occupied by anurans than those located more to the center (in the shade). There is strong evidence of an active selective process based on the quality of the water stored in the rosette, which differs between plants depending on their position in the scrub patch. Although the number of individuals varied during the period of study, the frequency of bromeliads used was constant, indicating that plant occupation follows a regular pattern throughout the year. Furthermore, the high frequency of bromeliads used by anurans during the whole year highlights the importance of considering these plants in developing conservation programs concerning the protection of anurans. RESUMO Dentre os vertebrados, anfibios anuros apresentam o maior numero de especies associadas a bromelias e possuem uma serie de especializacoes ecologicas, comportamentais e morfologicas para a vida nessas plantas. Apesar da importância das bromelias como amplificadoras de biodiversidade e sua riqueza de especies em alguns habitats, estudos sobre a relacao dos anuros com essas plantas sao escassos no Brasil. Neste trabalho investigamos o modo como anuros selecionam e utilizam bromelias em um ambiente costeiro ameacado. Analisamos dados oriundos de 23 amostras padronizadas da anurofauna associada a bromelia Neoregelia cruenta na restinga de Marica, sudeste do Brasil. Registramos nove especies de anuros utilizando esta bromelia, o que representa a maior riqueza ja reportada para uma restinga brasileira. Identificamos um padrao geral de utilizacao das bromelias em que plantas localizadas na borda das moitas (expostas ao sol) foram mais frequ' entemente ocupadas por anuros que aquelas localizadas mais ao centro (na sombra). Existe forte evidencia da existencia de um processo ativo de selecao baseado na qualidade da agua armazenada na roseta, que difere entre plantas dependendo de sua posicao na moita. Embora o numero de individuos tenha variado durante o periodo de estudo, a frequencia de bromelias utilizadas foi constante, indicando que a ocupacao das plantas segue um padrao regular ao longo do ano. Alem disso, a alta frequencia de bromelias utilizadas pelos anuros durante todo o ano ressalta a importância de se considerar essas plantas no desenvolvimento de programas de conservacao dedicados a protecao de anfibios anuros.

Are hybrid species more fit than ancestral parent species in the current hybrid species habitats?

Hybrid speciation is thought to be facilitated by escape of early generation hybrids into new habitats, subsequent environmental selection and adaptation. Here, we ask whether two homoploid hybrid plant species (Helianthus anomalus, H. deserticola) diverged sufficiently from their ancestral parent species (H. annuus, H. petiolaris) during hybrid speciation so that they are more fit than the parent species in hybrid species habitats. Hybrid and parental species were reciprocally transplanted into hybrid and parental habitats. Helianthus anomalus was more fit than parental species in the H. anomalus actively moving desert dune habitat. The abilities to tolerate burial and excavation and to obtain nutrients appear to be important for success in the H. anomalus habitat. In contrast, H. deserticola failed to outperform the parental species in the H. deserticola stabilized desert dune habitat, and several possible explanations are discussed. The home site advantage of H. anomalus is consistent with environmental selection having been a mechanism for adaptive divergence and hybrid speciation and supports the use of H. anomalus as a valuable system for further assessment of environmental selection and adaptive traits.