scholarly journals Planktonic diatom assemblage seasonal diversity used to assess environmental health in a coastal wetland of southern Chile

2020 ◽  
Author(s):  
Catalina Ríos-Henríquez ◽  
Norka Fuentes ◽  
Claudio N. Tobar ◽  
Jaime R. Rau ◽  
Fabiola Cruces

ABSTRACTAlthough planktonic diatoms are one of the most abundant taxonomic groups in coastal wetlands, their assemblages have not been used to determine the environmental health of these ecosystems. Studies of ecosystem environmental health have been based on other taxonomic groups; we propose that diatom genera diversity represents a viable alternative for this purpose. Thus, our aim was to determine the alpha and beta diversities of the planktonic diatom assemblage present in Caulín Bay, Chiloé Island (41° 49’S; 73° 38’O), southern Chile, during the austral winter and spring of the years 2012 and 2014. Inasmuch Caulín Bay is an important site for aquatic bird observation and conservation, hunting is prohibited on a national scale and, internationally, the site has been declared an Important Bird and Biodiversity Area (IBA). Our results indicate different diversities between sampling stations, but not between the years studied. In total, we recorded 53 diatom genera, of which the most abundant were Coscinodiscus (21.99%) and Cocconeis (16.23%). The study area presented high genera diversity (i.e., H’(log2) >3.74) and beta diversity indicated that Caulín presents a low level of heterogeneity and is a low genera replacement environment. Consequently, we infer that Caulín Bay is productive and environmentally stable ecosystem. This leads us to conclude that diatom diversity determination is a viable alternative to establish aquatic ecosystem environmental health and we recommend that future conservation strategies be established for Caulín Bay.RESUMENSi bien las diatomeas planctónicas son uno de los grupos taxonómicos más abundantes de los humedales costeros, sus ensambles no se han utilizado para determinar el estado ambiental de estos ecosistemas. Aunque se han realizado estudios de la salud ambiental de un ecosistema utilizando otros grupos taxonómicos, nosotros proponemos que la diversidad de géneros de diatomeas representa una alternativa viable. Por lo tanto, el objetivo de este estudio fue determinar las diversidades alfa y beta del ensamble de diatomeas planctónicas presentes en la Bahía de Caulín, Isla de Chiloé (41 ° 49’S; 73 ° 38’O), sur de Chile, durante las temporadas de invierno y primavera austral de los años 2012 y 2014. Bahía Caulín es un sitio importante para la observación y conservación de aves acuáticas por lo que a nivel nacional se ha prohibido la caza y a nivel internacional fue decretada un Área Importante para la Conservación de Aves, AICA. Los resultados de este estudio indicaron diferencias en las diversidades entre las estaciones de muestreo, pero no entre los años estudiados. En total, se identificaron 53 géneros de diatomeas; los más abundantes fueron Coscinodiscus (21,99%) y Cocconeis (16,23%). El área de estudio presentó una alta diversidad de géneros (i.e., H’(log2) >3.74) y la diversidad beta indicó que Caulín presentó bajo nivel de heterogeneidad y es un entorno con bajo reemplazo de géneros. Así, inferimos que Bahía Caulín es un ecosistema productivo y ambientalmente estable, por lo cual concluimos que la determinación de las diversidades de diatomeas es una alternativa para establecer la salud ambiental de los ecosistemas acuáticos y recomendamos establecer futuras estrategias de conservación para Bahía Caulín.PALABRAS CLAVE: diatomeas, diversidades ecológicas, plancton, humedales costeros, desembocadura

2020 ◽  
Vol 77 (2) ◽  
pp. 139-151
Author(s):  
Catalina Ríos-Henríquez ◽  
Norka Fuentes ◽  
Claudio N. Tobar ◽  
Jaime R. Rau ◽  
Fabiola Cruces

Lankesteriana ◽  
2011 ◽  
Vol 11 (3) ◽  
Author(s):  
Thomas Mirenda

Se ha escuchado a nivel mundial el llamado para la conservación de orquídeas, por parte de científicos, profesionales de horticultura, propagadores comerciales y los apasionados entusiastas privados, todos con diferentes opiniones sobre la manera para atacar este problema global. Las noticias han sido desalentadoras en relación al calentamiento global, destrucción de hábitat, desplazamiento de poblaciones nativas por parte de agresivas, exóticas e insostenibles depredaciones /cosechas de plantas y los esfuerzos impotentes para hacer cumplir las protecciones legales. Se han dedicado muchas ideas y esfuerzos para determinar estrategias específicas para la conservación de orquídeas, incluyendo la protección al hábitat, la compra y preservación de los “puntos calientes,” así como las tendencias hacia la creación de reservas hortícolas, tanto nativas (reservas de los Jardines de Lankester, Fundación EcoMinga, Ecuagenera) y ex situ (jardines de orquídeas en Hawái, colecciones bajo vidrio, etc.). Tácticas como un banco de semillas, tecnología ADN, esfuerzos de propagación ex situ, así como eventuales reintroducciones, inherentemente dependen de recursos y propiedades de jardines botánicos y cultivadores comerciales responsables. Es este tipo de trabajo de horticultura el que ha salvado a otros géneros que no corresponden a las orquídeas, tales como Franklinia, Torreya, Wollemia, y especies de orquídeas como Paphiopedilum vietnamense, Epidendrum ilense, y Angraecum longicalcar de la extinción. Los jardines botánicos unidos bajo ciertas organizaciones como la Asociación Americana de Jardines Públicos (American Public Garden Association - APGA) y Jardines Botánicos para la Conservación Internacional (Botanic Garden Conservation International - BGCI), necesitan de una mayor cooperación y coordinación para el éxito de sus esfuerzos para la conservación de plantas. Además, es un aspecto crítico que los jardines botánicos se conecten con la comunidad científica (y viceversa), especialmente aquellos que mejor pueden asesorar sobreaquellas especies más amenazadas. Si las colecciones van a ser utilizadas en forma óptima, las sociedades científicas y de horticultura deben estar más conscientes de sus respectivos activos y prioridades. En el Primer Congreso Internacional para la Conservación de Orquídeas (International Orchid Conservation Congress - IOCC), se adoptaron cuatro resoluciones de la Estrategia Global para la Conservación de Plantas (Global Strategy for Plant Conservation – GSPC en inglés): 1): el 90% de todas las orquídeas amenazadas deberían ser asegurada en colecciones ex situ; 2) el 50% debería constar en programas para su recuperación activa; 3) Se debe considerar que las orquídeas están amenazadas cuando su cosecha no es sostenible; y 4) Para el año 2010, cada niño y niña debe estar consciente de lo que es la diversidad de plantas (incluyendo a las orquídeas). ¿C.mo podemos evaluar si se está logrando el progreso hacia estos admirables objetivos sin que exista una entidad que unifique y que pueda recopilar el progreso, la información y el grado de éxitos alcanzado? Al ver el esfuerzo desplegado en tantos lugares separados, es indudable que se necesita urgentemente este tipo de entidad. Constituye la meta de muchos jardines botánicos y una meta específica del Instituto Smithsoniano, el promover la diseminación de conocimientos y comprensión. Con este fin en mente, el anterior objetivo #4 constituye una particular prioridad. A pesar de que alcanzar la meta del 100% de conciencia compartida en relación a la diversidad de plantas para el año 2010, hemos iniciado un proyecto que nos permita comprender y finalmente corregir el llamado síndrome de “Ceguera relativa a las Plantas,” bajo el cual la persona promedio no considera que las plantas son seres vivientes (en el mismo sentido de los animales). Mediante el uso de encuestas y entrevistas personales, se está analizando este síndrome generalizado y penetrante para determinar sus caracter.sticas demográficas, hombre/ mujer, urbano/rural, jóvenes/ viejos, etc. Es imperativo para los educadores que identifiquen la edad en la cual dichas actitudes empiezan a introducirse en la psiquis de los jóvenes. Es necesario aplicar ciertas técnicas que permitan elevar el grado de conciencia de los individuos de todas las edades en relación a la importancia de la diversidad de las plantas y su conservación. Esto puede tomar la forma de presentaciones, exposición a especies representativas, paseos de campo y otras oportunidades educativas, que permitan cultivar un enfoque mental que comprenda y a la final proteja el mundo natural. 


2017 ◽  
Vol 65 (3) ◽  
pp. 1062
Author(s):  
Luis Alberto Lara-Pérez ◽  
Ramón Zulueta-Rodríguez ◽  
Antonio Andrade-Torres

Ferns and lycophytes are a group of vascular plants of interest to understand the evolution of mycorrhizal interactions; their preservation is of relevance for their multiple ecological relations. The record of different taxonomic groups of fungi associated with ferns and lycophytes is fragmentary, and the criteria for it identification is inconsistent, which hinders the understanding and determination of mycorrhizal status. The aim of this study was to determine the percentage of the species of ferns and lycophytes with distribution in Mexico, and with information of fungal interactions. A checklist of the presence of arbuscular mycorrhizal fungi (AMF), Mucoromycotina and dark septate fungi (DSF) associated with ferns and lycophytes was integrated through an exhaustive global literature search. In this study, mycorrhizal species was considered by the presence of arbuscules to differentiate with hyphal, vesicular and coils colonization. The study gathered a checklist of mycorrhizal occurrences of 27 families, 61 genus and 137 species of ferns and lycophytes, which covers 13.4 % of the species, 91 % of the genus and 77 % of the families distributed in Mexico. The 78.1 % of the species showed colonization, 56.2 % by AMF, 29.9 % by DSF and 0.72 % by Mucoromycotina fungi. From the total of the species, the higher presences of colonization were in terrestrial, epiphytic, saxicolous, and aquatic plants with 76.6 %, 33.3 %, 20 %, and 6.3 %, respectively. The families of ferns and lycophytes with the higher number of species colonized were Pteridaceae, Polypodiaceae, Aspleniaceae and Dryopteridaceae. The present study showed the widespread associations of AMF and DSF in ferns and lycophytes of Mexico. It is urgently needed to include ferns and lycophytes in studies focused on endomycorhizal interactions, since only 28 species (28 %) were studied in Mexican ecosystems. The majority of studies were focused on sporophytic face (80 %). Nonetheless, to understand the role that plays the mycorrhiza in the establishment of ferns and lycophytes, it is necessary to include the gametophytic face in ecological, molecular and physiological experimental studies. This information is important to implement conservation strategies, because a considerable number of ferns and lycophytes species, depend on these mycorrhizal associations for their growth and survival. 


Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 350 ◽  
Author(s):  
Giorgos Maneas ◽  
Eirini Makopoulou ◽  
Dimitris Bousbouras ◽  
Håkan Berg ◽  
Stefano Manzoni

Human interventions during the last 70 years have altered the characteristics of the Gialova Lagoon, a coastal wetland that is part of a wider Natura 2000 site. In this study, we explore how human interventions and climate altered the wetland’s hydrological conditions and habitats, leading to changing wetland functions over time. Our interpretations are based on a mixed methodological approach combining conceptual hydrologic models, analysis of aerial photographs, local knowledge, field observations, and GIS (Geographic Information System) analyses. The results show that the combined effects of human interventions and climate have led to increased salinity in the wetland over time. As a result, the fresh and brackish water marshes have gradually been turned into open water or replaced by halophytic vegetation with profound ecological implications. Furthermore, current human activities inside the Natura 2000 area and in the surrounding areas could further impact on the water quantity and quality in the wetland, and on its sensitive ecosystems. We suggest that a more holistic understanding of the broader socio-ecological system is needed to understand the dynamics of the wetland and to achieve sustainable long-term management and conservation strategies.


2021 ◽  
Author(s):  
Yuka Owari ◽  
Fumi Nakamura ◽  
Yuya Oaki ◽  
Hiroyuki Tsuda ◽  
Shinji Shimode ◽  
...  

Abstract Silica frustules of most planktonic diatoms have many shallow holes in which the length (L) is smaller than the width (W). The present study focuses on a silicic ultrastructure of the setae of a planktonic diatom having deep (L/W > 1) holes. Here, we characterized nanoholes on the silica walls of hollow setae of a colony of Chaetoceros coarctatus. Basically, tetragonal poroid arrangements with and without a costa pattern are observed on the inner and outer surfaces, respectively, for three kinds of curving hollow setae. Deep nanoholes ∼90 nm wide are elongated from 150 to 1500 nm (L/W ∼17) with an increase in the wall thickness of the polygonal tubes of the setae. The inside poroid array, with a period of 190 nm in the extension direction of setae, is lined by parallel plates of the costae. However, the poroid arrangement on the outer surface is disordered, with several holes obstructed with increasing wall thickness of the posterior terminal setae. According to the movement of a colony in a fluid microchannel, the thick curving terminal setae is suggested to involve attitude control and mechanical protection. Using an optical simulation, the patterned deep through-holes on the intercalary setae were inferred to contribute anti-reflection of blue light for the promotion of photosynthesis in seawater.


2009 ◽  
Vol 59 (3) ◽  
pp. 335-349
Author(s):  
Luc De Bruyn ◽  
Henk Sierdsema ◽  
Hans Van Dyck ◽  
Chris van Swaay ◽  
Glenn Vermeersch ◽  
...  

AbstractNational or regional conservation strategies are usually based on available species distribution maps. However, very few taxonomic groups achieve a full coverage of the focal region. Distribution data of well-mapped taxonomic groups could help predict the distribution of less well-mapped groups and thus fill gaps in distribution maps. Here, we predict the distribution of five heathland butterflies in Flanders (north Belgium) using typical heathland bird distribution data as predictor variables. We compare predictions with those using only biotope or a combination of both biotope and bird data as variables. In addition, we test the transferability of 'bird', biotope and combined models to the Netherlands, an ecologically similar region. Transferability was tested in three separate sandy regions in the Netherlands at different distances from the region in which the models were built. For each of the five heathland butterflies, we applied logistic regressions on ten random model sets and tested the models on ten random evaluation sets within Flanders. We used the area under the curve (AUC) of the receiver-operating characteristics (ROC) plots to estimate model accuracy. Overall, bird models performed significantly better than biotope models but were not significantly different from the combined models in Flanders. In the Netherlands, the transferred biotope and the combined models performed better than the transferred 'bird models'. We conclude that on a local scale, birds can, to some extent, serve as proxies for biotope quality, but that biotope models are more robust when transferred to another region.


2016 ◽  
Vol 113 (23) ◽  
pp. 6388-6396 ◽  
Author(s):  
Nicole L. Boivin ◽  
Melinda A. Zeder ◽  
Dorian Q. Fuller ◽  
Alison Crowther ◽  
Greger Larson ◽  
...  

The exhibition of increasingly intensive and complex niche construction behaviors through time is a key feature of human evolution, culminating in the advanced capacity for ecosystem engineering exhibited by Homo sapiens. A crucial outcome of such behaviors has been the dramatic reshaping of the global biosphere, a transformation whose early origins are increasingly apparent from cumulative archaeological and paleoecological datasets. Such data suggest that, by the Late Pleistocene, humans had begun to engage in activities that have led to alterations in the distributions of a vast array of species across most, if not all, taxonomic groups. Changes to biodiversity have included extinctions, extirpations, and shifts in species composition, diversity, and community structure. We outline key examples of these changes, highlighting findings from the study of new datasets, like ancient DNA (aDNA), stable isotopes, and microfossils, as well as the application of new statistical and computational methods to datasets that have accumulated significantly in recent decades. We focus on four major phases that witnessed broad anthropogenic alterations to biodiversity—the Late Pleistocene global human expansion, the Neolithic spread of agriculture, the era of island colonization, and the emergence of early urbanized societies and commercial networks. Archaeological evidence documents millennia of anthropogenic transformations that have created novel ecosystems around the world. This record has implications for ecological and evolutionary research, conservation strategies, and the maintenance of ecosystem services, pointing to a significant need for broader cross-disciplinary engagement between archaeology and the biological and environmental sciences.


Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 265
Author(s):  
Felix I. Rossbach ◽  
Edoardo Casoli ◽  
Milan Beck ◽  
Christian Wild

The Mediterranean Sea harbors more than 17,000 eukaryotic marine species, with several ecosystems recognized as biodiversity hotspots, such as Posidonia oceanica meadows. Recent research indicates that benthic mats formed by the fleshy red alga Phyllophora crispa are also associated with high species richness. Among key groups found in these mats are sessile polychaetes, which live as epiphytes on the red algae thalli. Knowledge of abundance, species richness, and spatial variation of polychaetes associated with these habitats is still scarce. We carried out a comparative assessment focusing on serpulid polychaetes within samples from P. crispa mats and neighboring P. oceanica meadows at six different sampling sites around Giglio Island (Tyrrhenian Sea, Italy). A total of 17 serpulid taxa were identified. The abundance of serpulids (5665 individuals m−2 of P. crispa mat) were similar to neighboring P. oceanica meadows (2304 individuals m−2 leaves and 5890 individuals m−2 shoots). The number of serpulid taxa was significantly higher in P. crispa mats (average 6.63 ± 1.32 taxa) compared to P. oceanica beds (average 1.56 ± 0.63 and 1.84 ± 1.04 taxa in leaves and shoots, respectively). Within habitat type, there were no significant differences in species richness between sites. The most abundant species found was Josephella marenzelleri (61% of individuals), while Vermiliopsis spp. and Bathyvermilia sp. were exclusively found in P. crispa samples. Our results highlight that P. crispa mats host an exceptional diversity and that these habitats should be included in conservation strategies. Further research should focus on the significance of other important taxonomic groups within these mats and evaluate the distribution of P. crispa in different regions of the Mediterranean Sea.


FACETS ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 49-66
Author(s):  
Jessica Currie ◽  
Valentina Marconi

The identification of factors that predict trends in population abundance is critical to formulate successful conservation strategies. Here, we explore population trends of Canadian vertebrates assessed as “at-risk” by the Committee on the Status of Endangered Wildlife in Canada and the threats affecting these trends using data from the Canadian Living Planet Index. We investigate how threat profiles—the combination of threats for a given species—vary among species and taxonomic groups. We then investigate threat profile as a predictor of temporal trends—both exclusively and in combination with additional biotic and abiotic factors. Species had 5.06 (±2.77) threats listed on average, and biological resource use (BRU) was the most frequently cited. Our analysis also revealed an association between taxonomic group and population trends, as measured by the proportion of annual increases (years with a positive interannual change). By contrast, the predictive power of threat profile was poor. This analysis yielded some useful insight for conservation action, particularly the prioritization of abating BRU. However, the predictive models were not as meaningful as originally anticipated. We provide recommendations on methodological improvements to advance the understanding of factors that predict trends in population abundance for prioritizing conservation action.


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