The pond biodiversity index "IBEM", a new tool for the rapid assessment of biodiversity in ponds from Switzerland. Part 2. Method description and examples of application

Ponds are now widely recognized to contribute significantly to regional freshwater biodiversity. Therefore, tools to easily and rapidly assess biological quality specificalIy for these aquatic habitats have been increasingly requested by conservation planners and nature managers. In c10se association with practitioners, we developed such a method for Switzerland; the pond biodiversity index "IBEM". The IBEM-Index is based on the assessment of the taxonomic richness of 5 groups: aquatic vege­tation, Gastropoda, Coleoptera, adult Odonata and Amphibia. No abundance data are necessary and genus level identification is required for alI groups except Amphibia (species level). The sampling methodology is a stratified random strategy and alIows the use of richness estimators to transform the observed taxonomic richness (Sobs) into true taxonomic richness (Strue). As the IBEM assessment folIows the methodology presented in the Water Framework Directive, it is based on the caIculation of the ratio of true taxonomic richness (Strue) to reference-based predicted richness (Sref)' Each of the five taxonomic groups is assessed separately and the overalI biological quality of any given pond (i.e. the IBEM-Index) is the average of the five ratios. This score is later converted into one of five quality c1asses for each pond: bad (O to 0.2), poor (> 0.2 to 0.4), moderate (> 0.4 to 0.6), good (> 0.6 to 0.8), and high (> 0.8 to 1). In this paper, the implementation of the IBEM-Index is described in detail. The sampling methodologies are developed (for the biodiversity and the environmental variables) as welI as the assessment methodology. FinalIy, two examples are presen­ted in detail, for a "good" quality pond and for a "bad" quality pond. The method implementation also includes a website (http://campus.hesge.ch/ibem) which a1lows the online caIculation of the index, and provides support for both sampling and assessment methodologies to users. The IBEM-Index is a rapid assessment method which gives an overalI value of pond biodiversity in terms of taxa richness and can be used, for example, in regional screenings or site monitoring in Switzerland. Moreover, as biodiversity is generalIy recognized as a good indicator of global ecological quality, the IBEM-Index can also be used to investigate ecosystem quality.Está ampliamente reconocido que las pequeñas masas de agua (charcas) contribuyen de forma significativa a la biodiversi­dad regional de las aguas dulces. Por tanto, las herramientas que de manera rápida y fácil evalúen especíjicamente la calidad biológica de estos hábitats acuáticos están siendo requeridas cada vez más por profesionales de la gestión y conservación del medio natural. En estrecha colaboración con estos profesionales, se ha desarrollado un método de este tipo para Suiza; el índice de biodiversidad de charcas "IBEM". El Índice-IBEM se basa en la evaluación de la riqueza taxonómica de 5 grupos: vegetación acuática, gasterópoda, coleópteros, odonatos (adultos) y anfibios. No son necesarios datos de abundancia y se requiere un nivel identificación de género para todos los grupos excepto para los anfibios (nivel de especie). Se usa un muestreo aleatorio estratificado que permite obtener estimadores para transformar la riqueza taxonómica observada (Sobs) en riqueza taxonómica real (Strue)' La evaluación IBEM sigue la metodología de la Directiva Marco del Agua, que se basa en el cálculo de la relación entre la riqueza taxonómica real (Strue) y la riqueza esperable en un estado de referencia (Sre!)' Cada uno de los cinco grupos taxonómicos se evalúa por separado y la calidad biológica de una charca determinada (Índice-IBEM) es la media de los cinco coeficientes. Este resultado es posterionnente asignado a una de las cinco clases de calidad: malo (O a 0.2), deficiente (> 0.2 a 0.4), moderado (> 0.4 a 0.6), bueno (> 0.6 to 0.8), y muy bueno (> 0.8 al). En este artículo, se describe detalladamente la aplicación del índice IBEM y se desarrollan las metodologías de mues­treo (para la biodiversidad y las variables ambientales) y de valoración utilizadas. Por último, se presentan con detalle dos ejemplos, una charca con "buena" calidad y otra con "mala" calidad. Se incluye también una página web (http://campus.hesge.ch/ibem), que permite el cálculo del índice a través de intemet y sirve de apoyo a los usuarios en las metodologías de muestreo y de valoración. El índice IBEM es un método de evaluación rápida que da un valor general de la diversidad biológica de una charca en términos de riqueza de taxones y se puede utilizar, por ejemplo, a nivel regional o en el seguimiento de una localidad, en Suiza. Además, como la biodiversidad es un buen indicador de la calidad ecológica global, el índice IBEM también se puede usar para evaluar el estado del ecosistema

The pond biodiversity index "IBEM", a new tool for the rapid assessment of biodiversity in ponds from SwitzerlandPart 1. Index development

Due to legal requirements, nature managers increasingly have to carry out assessments of biodiversity for conservation purpo­seso For ponds, a type of waterbody now widely recognized as an important reservoir for freshwater biodiversity, standardized bioassessment methods are needed, but still rare. We produced such a tool for smalllowland waterbodies in Switzerland: the Pond Biodiversity Index ("IBEM"). This Index is the adaptation of a method used by researchers for assessing the biodiver­sity in ponds, PLOCH, which does not currently meet the requirements for routine use by nature managers because it is too expensive and requires a high skill level in taxonomic identification. A method intended for practitioners has to be simple, standardized, cheap, adjustable, and consistent with the legislative framework. In order to fulfill these requirements, the theoretical and practical aspects of IBEM were developed with a group of representative end users including nature conservation managers, consuitants, govemmental organizations and taxonomic experts. To develop the method, we used a species dataset from 63 Swiss lowland ponds which included five taxonomic groups: aquatic plants, aquatic Gastropoda, aquatic Coleopte­ra, adult Odonata and Amphibia. The following topics were addressed: (i) the number and type of taxonomic groups which should be used for producing the index (is it possible to use surrogates?) (ii) the level of identification for each taxonomic group (species? genus? family?) (iii) the sampling strategy (sampling technique, number of replicates), (iv) the calculation of a unique index and the strategy for assessing its score, and (v) the transfer of this new method to end users. The new method IBEM uses all five taxonomic groups, because a subset of groups did not produce reliable assessments of pond biodiversity. Identification to genus level is required for four groups (aquatic plants, aquatic Gastropoda, aquatic Coleoptera, aduit Odona­ta) and species level for Amphibia. The sampling methodology is based on the stratified random strategy used in the PLOCH method, but with a slight modification in the number of samples per pond. The assessment follows the methodology adopted by the European Water Framework Directive, and the ratio of the observed richness to a reference-based predicted richness is translated into one of five quality categories for each pond. The final index is the mean of the five assessment scores. To facilitate the implementation of the IBEM method, a website (http://campus.hesge.ch/ibem) enables online calculation of the index, and provides instructions on both sampling and assessment methodologies. Furthermore, training courses are organized by the authors of the method for end users.Debido a requerimientos legales, es cada vez más necesario que los gestores del medio ambiente lleven a cabo evaluaciones de la biodiversidad dirigidas a la conservación de la naturaleza. Para las charcas, pequeñas masas de agua ampliamente reconocidas como importantes reservorios de diversidad biológica acuática, los métodos normalizados de bio-evaluación son necesarios, pero aún escasos. Para esta tipología de pequeñas masas de agua situadas a baja altitud en Suiza se ha elaborado el índice de Biodiversidad de charcas ("IBEM"). Este índice es la adaptación de un método utilizado por los investigadores para evaluar la diversidad biológica en charcas, PLOCH, que no cumplía los requisitos para un uso rutinario por parte de los gestores del medio natural por ser demasiado caro y requerir un alto nivel de experiencia en la identificación taxonómica. Un método destinado a estos profesionales tiene que ser sencillo, estandarizado, económico, ajustable y en consonancia con el marco legislativo. Con el fin de cumplir estos requisitos, los aspectos teóricos y prácticos de IBEM se han desarrollado con un grupo representativo de posibles usuarios, incluyendo gestores conservadores, consultores, organizaciones guber­namentales y expertos en taxonomía. Para desarrollar el método, se ha utilizado una base de datos de 63 charcas Suizas, situadas en altitudes bajas, que incluye cinco grupos taxonómicos: plantas acuáticas, gasterópodos acuáticos, coleópteros acuáticos, odonatos adultos y anfibios. Se han estudiado los siguientes aspectos: (i) el número y tipo de grupos taxonómicos que se deben utilizar (es posible el uso de sustitutos?) (ii) nivel de identificación para cada grupo taxonómico (¿especie, género, familia?) (iii) estrategia de muestreo (técnica, número de réplicas), (iv) cálculo de un índice único y procedimiento para la asignación de valores y (v) la transferencia de este método a los posibles usuarios. El nuevo método IBEM utiliza los cinco grupos taxonómicos, ya que un subconjunto de ellos no produciría evaluaciones fiables de la diversidad biológica de la charca. La identificación a nivel de género es necesaria para cuatro de estos grupos (plantas acuáticas, gasterópodos acuáticos, coleópteros acuáticos, y odonatos adultos) y para los anfibios es necesario el nivel de especie. El muestreo sigue un diseño aleatorio estratificado, utilizado en el método PLOCH, pero con una ligera modificación en el número de muestras por charca. La evaluación sigue la metodología adoptada por la Directiva Marco de Aguas, y la relación entre la riqueza observada y la del estado de referencia se traduce en una de las cinco categorías de calidad para cada charca. El índice final es la media de las cinco puntuaciones de la evaluación. Para facilitar la aplicación del método IBEM, un sitio web (http://campus.hesge.ch/ibem) permite cálculo del índice a través de la red y proporciona instrucciones tanto de las metodo­logías de muestreo como de la valoración. Además, los autores han organizado cursos de formación sobre el método para los usuarios

Macroinvertebrate assemblages in 25 high alpine ponds of the Swiss National Park (Cirque of Macun) and relation to environmental variables

High-altitude freshwater ecosystems and their biocoenosis are ideal sentinel systems to detect global change. In particular, pond communities are likely to be highly responsive to climate warming. For this reason, the Swiss National Park has included ponds as part of a long-term monitoring programme of the high-alpine Macun cirque. This cirque covers 3.6km2, has a mean altitude of 2,660m a.s.l., and includes a hydrographic system composed of a stream network and more than 35 temporary and permanent ponds. The first two steps in the programme were to (i) make an inventory of the macroinvertebrates of the waterbodies in the Macun cirque, and (ii) relate the assemblages to local or regional environmental variables. Sampling was conducted in 25ponds between 2002 and 2004. The number of taxa characterising the region (Macun cirque) was low, represented by 47 lentic taxa. None of them was endemic to the Alps, although several species were cold stenothermal. Average pond richness was low (11.3 taxa). Assemblages were dominated by Chironomidae (Diptera), and Coleoptera and Oligochaeta were also relatively well represented. Other groups, which are frequent in lowland ponds, had particularly poor species richness (Trichoptera, Heteroptera) or were absent (Gastropoda, Odonata, Ephemeroptera). Macroinvertebrate assemblages (composition, richness) were only weakly influenced by local environmental variables. The main structuring processes were those operating at regional level and, namely, the connectivity between ponds, i.e. the presence of a physical connection (tributary) and/or small geographical distance between ponds. The results suggest that during the long-term monitoring of the Macun ponds (started in 2005), two kinds of change will affect macroinvertebrate assemblages. The first change is related to the natural dynamics, with high local-scale turnover, involving the metapopulations characterising the Macun cirque. The second change is related to global warming, leading to higher local and regional richness through an increase in the number of colonisation events resulting from the upward shift of geographical ranges of species. At the same time the cold stenothermal species from Macun will be subject to extinctio

Temporal dynamics of aquatic communities and implications for pond conservation

Conservation through the protection of particular habitats is predicated on the assumption that the conservation value of those habitats is stable. We test this assumption for ponds by investigating temporal variation in macroinvertebrate and macrophyte communities over a 10-year period in northwest England. We surveyed 51 ponds in northern England in 1995/6 and again in 2006, identifying all macrophytes (167 species) and all macroinvertebrates (221 species, excluding Diptera) to species. The alpha-diversity, beta-diversity and conservation value of these ponds were compared between surveys. We find that invertebrate species richness increased from an average of 29. 5 species to 39. 8 species between surveys. Invertebrate gamma-diversity also increased between the two surveys from 181 species to 201 species. However, this increase in diversity was accompanied by a decrease in beta-diversity. Plant alpha-, beta and gamma-diversity remained approximately constant between the two periods. However, increased proportions of grass species and a complete loss of charophytes suggests that the communities are undergoing succession. Conservation value was not correlated between sampling periods in either plants or invertebrates. This was confirmed by comparing ponds that had been disturbed with those that had no history of disturbance to demonstrate that levels of correlation between surveys were approximately equal in each group of ponds. This study has three important conservation implications: (i) a pond with high diversity or high conservation value may not remain that way and so it is unwise to base pond conservation measures upon protecting currently-speciose habitats; (ii) maximising pond gamma-diversity requires a combination of late and early succession ponds, especially for invertebrates; and (iii) invertebrate and plant communities in ponds may require different management strategies if succession occurs at varying rates in the two groups

Gravel pits support waterbird diversity in an urban landscape

We assessed the benefit of 11 gravel pits for the settlement of waterbird communities in an urbanized area lacking natural wetlands. Gravel pits captured 57% of the regional species pool of aquatic birds. We identified 39 species, among which five were regionally rare. We used the Self Organizing Map algorithm to calculate the probabilities of presence of species, and to bring out habitat conditions that predict assemblage patterns. The age of the pits did not correlate with assemblage composition and species richness. There was a positive influence of macrophyte cover on waterbird species richness. Larger pits did not support more species, but species richness increased with connectivity. As alternative wetland habitats, gravel pits are attractive to waterbirds, when they act as stepping stones that ensure connectivity between larger natural and/or artificial wetlands separated in space

Environmental determinants of macroinvertebrate diversity in small water bodies: insights from tank-bromeliads

The interlocking leaves of tank-forming bromeliads (Bromeliaceae) collect rainwater and detritus, thus creating a freshwater habitat for specialized organisms. Their abundance and the possibility of quantifying communities with accuracy give us unparalleled insight into how changes in local to regional environments influence community diversity in small water bodies. We sampled 365 bromeliads (365 invertebrate communities) along a southeastern to northwestern range in French Guiana. Geographic locality determined the species pool for bromeliad invertebrates, and local environments determined the abundance patterns through the selection of traits that are best adapted to the bromeliad habitats. Patterns in community structure mostly emerged from patterns of predator species occurrence and abundance across local-regional environments, while the set of detritivores remained constant. Water volume had a strong positive correlation with invertebrate diversity, making it a biologically relevant measure of the pools' carrying capacity. The significant effects of incoming detritus and incident light show that changes in local environments (e.g., the conversion of forest to cropping systems) strongly influence freshwater communities. Because changes in local environments do not affect detritivores and predators equally, one may expect functional shifts as sets of invertebrates with particular traits are replaced or complemented by other sets with different traits

Etude des mares du parc Naturel Régional des Causses du Quercy : fonctionnement, biodiversité et connectivité inter-mares. Propositions pour l'entretien et la sauvegarde.

In the arid karstic region of the “Causses du Quercy” (SW France), ponds constitute the only available surface water resource on this limestone plateau.As the natural evolution of ponds leads to the filling up of these ecosystems, a comparative study of three ponds at various stages of succession showed the evolution of abiotics parameters (temperature, oxygen concentration...) as a function of stages of succession. Concurrently, ponds varied in terms of plant and animal species richness. Each pond supported a distinctive fauna and took part in the global biodiversity of these ecosystems.At a larger scale, thirty ponds where studied to investigate factors affecting the distribution of fauna in a pond network. We identified 230 species of invertebrates and 6 species of vertebrates. Results do not permit to draw up a typology of ponds or to highlight characteristics communities of these ponds. As ponds surrounded by terrestrial landscape constitute “islands” for the aquatic fauna, five taxonomic groups were chosen based on theirdifferent capabilities of dispersion to study the species distribution: Odonata, Coleoptera, Amphibia, Mollusca and Oligochaeta. For Odonata, pond area influence species distribution. For amphibia, forested ponds are more likely to include all the species. For both Mollusca and Oligochaeta, the passive dispersers, the results indicate that the species distribution is a randomised distribution. For Coleoptera, the distribution is not a randomised distribution but we do not find the factors which could explain this distribution.Then, we used the capture-mark-recapture technique in order to estimate the degree of linkage in three patchy populations of odonate localised on three ponds. We demonstrated that three factors influence the dispersal ability of these odonates: abiotic factors (especially weather conditions), interspecific differences (sensitivity to weather conditions, species size and behaviour), intraspecific characteristics (sex and age).This study underlines the role of ponds in the biodiversity of the study area and the role of pond network and of the temporal evolution of these ponds in the maintenance of this biodiversity. Results are discussed in order to propose management plans to maintain the biodiversity of these ecosystems.Sur les Causses arides du Quercy (S.-O. de la France), de nombreuses mares ont été creusées dans la roche. Ces mares constituent les seules eaux superficielles de ce plateau calcaire où l'eau s'infiltre rapidement.L'évolution naturelle des mares conduit à leur atterrissement et une étude comparative de trois mares à différents stades de comblement a montré l'évolution des paramètres abiotiques (température, concentration en oxygène dissous...) en fonction du niveau de comblement. Parallèlement, les mares varient en terme de richesse spécifique de la faune et de la flore. Chaque stade de comblement abrite une faune particulière et participe à la biodiversité globale de ces milieux et même de l'écosystème caussenard dans son ensemble.Pour analyser ces milieux à une échelle supérieure, des échantillons ont été récoltés sur trente mares afin d'étudier les facteurs affectant la distribution de la faune dans un réseau de mares. Nous avons identifié 230 espèces d'invertébrés et 6 espèces de vertébrés. Les résultats ainsi obtenus ne permettent pas de dresser une typologie des mares ni de dégager des peuplements caractéristiques ou de réaliser une classification ascendante de ces milieux. Les mares entourées d'une matrice terrestre sont assimilables à des îles pour la faune aquatique.C'est pourquoi nous avons choisi d'étudier plus précisément la distribution de cinq groupes ayant des capacités de dispersion différentes : Odonates, Coléoptères, Amphibiens, Mollusques et Oligochètes. La surface des mares affecte la distribution des Odonates. Le pourcentage de forêt autour des mares influence la distribution desAmphibiens. Pour les Mollusques et les Oligochètes, les animaux à dispersion passive, les résultats indiquent que la distribution des espèces est similaire à une distribution au hasard. Pour les Coléoptères, la distribution des espèces n'est pas due au hasard mais nous n'avons pas pu mettre en évidence les facteurs explicatifs de cette distribution.Nous avons utilisé la méthode de capture-marquage-recapture pour estimer le degré de lien de trois populations en patch d'Odonates. Nous avons montré que trois facteurs influencent la dispersion des Odonates : des facteurs abiotiques (conditions météorologiques), des différences inter spécifique (sensibilité aux conditions météorologiques, taille et comportement des espèces), des différences intra spécifiques (âge et sexe).Ces travaux mettent en évidence le rôle des mares au niveau de la biodiversité, le rôle du réseau de mares et de l'évolution temporelle des paramètres dans le maintien de cette biodiversité. Les différents résultats obtenus sont discutés en vue de proposer une méthode de gestion rationnelle et durable de ces milieux

Biodiversity and distribution patterns of freshwater invertebrates in farm ponds of a south-western French agricultural landscape

International audienc