Effectiveness of management zoning designed for flagship species in protecting sympatric species.

Flagship species have been used widely as umbrella species (i.e., species with large home range whose protection often provides protection for sympatric species) in the management of China's nature reserves. This conflation of flagship and umbrella species is best represented by the giant panda (Ailuropoda melanoleuca) and other large, endangered mammals designated as conservation targets in site selection and planning of reserves. Few empirical studies have tested the effectiveness of flagship species as surrogates for a broader range of sympatric species. Using extensive camera-trap data, we examined the effectiveness of management zones designated to protect flagship (target) species in conserving sympatric species in 4 wildlife reserves (Gutianshan, Changqing, Laohegou, and Wolong). We tested whether the progression from peripheral to core zones was associated with an increasing habitat association for both target and sympatric species. The distribution patterns of the study species across the zones in each reserve indicated a disparity between management zones and the species' habitat requirements. Management zone was included in the final model for all target species, and most of them had higher occurrence in core zones relative to less-protected zones, but zone was not a predictor for most of the sympatric species. When management zone was associated with the occurrence of sympatric species, threatened species generally had higher detections in core zones, whereas common species had higher detections outside of the core zone. Our results suggested that reserve planning based on flagship species does not adequately protect sympatric species due to their specialized habitat requirements. We recommend re-examining the effectiveness of management zoning and urge a multispecies and reserve-wide monitoring plan to improve protection of China's wildlife.

Efectividad del Manejo de Zonación Diseñada para Especies Bandera en la Protección de Especies Simpátricas Resumen Las especies bandera se han utilizado ampliamente como especies paraguas (es decir, especies con una extensa distribución cuya protección frecuentemente proporciona protección para especies simpátricas) en el manejo de las reservas naturales de China. Esta combinación de especie bandera y especie paraguas tiene su mejor representación en el panda gigante (Ailuropoda melanoleuca) y otros grandes mamíferos en peligro de extinción designados como objetivos de conservación en la selección de sitio y la planeación de reservas. Pocos estudios empíricos han probado la efectividad de las especies bandera como sustitutas de una especie simpátrica con una distribución más amplia. Con datos numerosos de cámaras trampa, examinamos la efectividad de las zonas de manejo designadas para proteger a las especies bandera (objetivo) en la conservación de especies simpátricas dentro de cuatro reservas de fauna (Gutianshan, Changqing, Laohegou y Wolong). Probamos si la progresión de las zonas periféricas hacia las zonas núcleo estaba relacionada con asociaciones crecientes de hábitat tanto para las especies objetivo como para las simpátricas. Los patrones de distribución del estudio de especies a lo largo de las zonas en cada reserva indicaron una disparidad entre las zonas de manejo y los requerimientos de hábitat de las especies. La zona de manejo se incluyó dentro del modelo final para todas las especies objetivo y la mayoría de ellas tuvo una presencia más alta en las zonas núcleo en relación con las zonas de menor protección. Cuando la zona de manejo se asoció a la presencia de especies simpátricas, las especies amenazadas generalmente tuvieron un mayor número de detecciones en la zona núcleo, mientras que las especies comunes tuvieron un número más elevado de detecciones fuera de la zona núcleo. Nuestros resultados sugieren que la planeación de reservas basada en las especies bandera no protege adecuadamente a las especies simpátricas debido a sus requerimientos especializados de hábitat. Recomendamos una reexaminación de la efectividad del manejo de zonación y urgimos que se genere un plan de monitoreo multiespecífico en toda la reserva para mejorar la protección de la fauna en China.

Countering resistance to protected-area extension.

The establishment of protected areas is a critical strategy for conserving biodiversity. Key policy directives like the Aichi targets seek to expand protected areas to 17% of Earth's land surface, with calls by some conservation biologists for much more. However, in places such as the United States, Germany, and Australia, attempts to increase protected areas are meeting strong resistance from communities, industry groups, and governments. We examined case studies of such resistance in Victoria, Australia, Bavaria, Germany, and Florida, United States. We considered 4 ways to tackle this problem. First, broaden the case for protected areas beyond nature conservation to include economic, human health, and other benefits, and translate these into a persuasive business case for protected areas. Second, better communicate the conservation values of protected areas. This should include highlighting how many species, communities, and ecosystems have been conserved by protected areas and the counterfactual (i.e., what would have been lost without protected area establishment). Third, consider zoning of activities to ensure the maintenance of effective management. Finally, remind citizens to think about conservation when they vote, including holding politicians accountable for their environmental promises. Without tackling resistance to expanding the protected estate, it will be impossible to reach conservation targets, and this will undermine attempts to stem the global extinction crisis.

Applying network theory to prioritize multispecies habitat networks that are robust to climate and land-use change.

Designing connected landscapes is among the most widespread strategies for achieving biodiversity conservation targets. The challenge lies in simultaneously satisfying the connectivity needs of multiple species at multiple spatial scales under uncertain climate and land-use change. To evaluate the contribution of remnant habitat fragments to the connectivity of regional habitat networks, we developed a method to integrate uncertainty in climate and land-use change projections with the latest developments in network-connectivity research and spatial, multipurpose conservation prioritization. We used land-use change simulations to explore robustness of species' habitat networks to alternative development scenarios. We applied our method to 14 vertebrate focal species of periurban Montreal, Canada. Accounting for connectivity in spatial prioritization strongly modified conservation priorities and the modified priorities were robust to uncertain climate change. Setting conservation priorities based on habitat quality and connectivity maintained a large proportion of the region's connectivity, despite anticipated habitat loss due to climate and land-use change. The application of connectivity criteria alongside habitat-quality criteria for protected-area design was efficient with respect to the amount of area that needs protection and did not necessarily amplify trade-offs among conservation criteria. Our approach and results are being applied in and around Montreal and are well suited to the design of ecological networks and green infrastructure for the conservation of biodiversity and ecosystem services in other regions, in particular regions around large cities, where connectivity is critically low.

Improving effectiveness of systematic conservation planning with density data.

Systematic conservation planning aims to design networks of protected areas that meet conservation goals across large landscapes. The optimal design of these conservation networks is most frequently based on the modeled habitat suitability or probability of occurrence of species, despite evidence that model predictions may not be highly correlated with species density. We hypothesized that conservation networks designed using species density distributions more efficiently conserve populations of all species considered than networks designed using probability of occurrence models. To test this hypothesis, we used the Zonation conservation prioritization algorithm to evaluate conservation network designs based on probability of occurrence versus density models for 26 land bird species in the U.S. Pacific Northwest. We assessed the efficacy of each conservation network based on predicted species densities and predicted species diversity. High-density model Zonation rankings protected more individuals per species when networks protected the highest priority 10-40% of the landscape. Compared with density-based models, the occurrence-based models protected more individuals in the lowest 50% priority areas of the landscape. The 2 approaches conserved species diversity in similar ways: predicted diversity was higher in higher priority locations in both conservation networks. We conclude that both density and probability of occurrence models can be useful for setting conservation priorities but that density-based models are best suited for identifying the highest priority areas. Developing methods to aggregate species count data from unrelated monitoring efforts and making these data widely available through ecoinformatics portals such as the Avian Knowledge Network will enable species count data to be more widely incorporated into systematic conservation planning efforts.

Mejoría de la Efectividad de la Planeación Sistemática de la Conservación con Datos de Densidad Resumen La planeación sistemática de la conservación tiene como meta diseñar redes de áreas protegidas que cumplan con objetivos de conservación a lo largo de grandes paisajes. El diseño óptimo de estas redes de conservación se basa con mayor frecuencia en modelos de idoneidad de hábitat o probabilidad de occurrencia de especies, a pesar de la evidencia existente de que las predicciones de esos modelos pueden no estar fuertemente correlacionadas con la densidad de especies. Hipotetizamos que las redes de conservación diseñadas con las distribuciones de la densidad de especies conservan con mayor eficiencia a las poblaciones de todas las especies consideradas que las redes diseñadas con modelos de probabilidad de occurencia. Para probar esta hipótesis usamos el algoritmo Zonation de planeación de la conservación para evaluar los diseños de redes de conservación basados en la probabilidad de ocurrencia versus los modelos de densidad para 26 especies de aves terrestres en el noroeste del Pacífico en los Estados Unidos. Evaluamos la efectividad de cada red de conservación con base en las densidades pronosticadas de cada especie y la diversidad de especies pronosticada. Las clasificaciones de Zonation de los modelos de alta densidad protegieron a más individuos por especie cuando las redes protegieron el 10-40% de la más alta prioridad del paisaje. Comparado con los modelos basados en la densidad, los modelos basados en la ocurrencia protegieron a más individuos en el 50% más bajo de las áreas prioritarias de los paisajes. Las dos estrategias conservaron la diversidad de especies de formas similares: la diversidad pronosticada fue más alta en las localidades de alta prioridad en ambas redes de conservación. Concluimos que tanto los modelos de densidad como los de probabilidad de ocurrencia pueden ser útiles para establecer prioridades de conservación, pero que los modelos basados en la densidad son más adecuados para identificar las áreas de más alta prioridad. Desarrollar métodos para agregar datos de conteos de especies a partir de esfuerzos de monitoreo no relacionados y hacer que estos datos estén disponibles en portales eco-informáticos como la Avian Knowledge Network permitirá que los datos de conteos de especies se incorporen más ampliamente en esfuerzos de planeación sistemática de la conservación.

Conservation businesses and conservation planning in a biological diversity hotspot.

The allocation of land to biological diversity conservation competes with other land uses and the needs of society for development, food, and extraction of natural resources. Trade-offs between biological diversity conservation and alternative land uses are unavoidable, given the realities of limited conservation resources and the competing demands of society. We developed a conservation-planning assessment for the South African province of KwaZulu-Natal, which forms the central component of the Maputaland-Pondoland-Albany biological diversity hotspot. Our objective was to enhance biological diversity protection while promoting sustainable development and providing spatial guidance in the resolution of potential policy conflicts over priority areas for conservation at risk of transformation. The conservation-planning assessment combined spatial-distribution models for 646 conservation features, spatial economic-return models for 28 alternative land uses, and spatial maps for 4 threats. Nature-based tourism businesses were competitive with other land uses and could provide revenues of >US$60 million/year to local stakeholders and simultaneously help meeting conservation goals for almost half the conservation features in the planning region. Accounting for opportunity costs substantially decreased conflicts between biological diversity, agricultural use, commercial forestry, and mining. Accounting for economic benefits arising from conservation and reducing potential policy conflicts with alternative plans for development can provide opportunities for successful strategies that combine conservation and sustainable development and facilitate conservation action.

Macrofauna bentónica de las playas de arena del Área de Conservación Osa, Puntarenas, Pacífico Sur de Costa Rica / Benthic macrofauna found in Sandy beaches from Osa Conservation Area, Puntarenas, Southern Pacific coast of Costa Rica

Resumen Se describe la diversidad y composición de especies las playas de arena del Pacífico Sur de Costa Rica. En las playas de arena de la región, se colectó individuos de la infauna por medio de barrenos. Para la zona de entre mareas arenosa el número de especies estrictamente marina varió de 5 a 13 taxones, número que es intermedio con los reportados previamente para estos ambientes en Costa Rica. En la zonas de arena, el supralitoral lo dominó el isópodo Cirolana salvadorensis, mientras nereidos y un gusano de la Familia Pisionidae dominaron en el infralitoral. Otros organismos encontrados en las playas fueron cangrejos del género Uca, cangrejos anomuros (Emerita), galletas de mar (Mellita longifissa) y varios grupos de poliquetos tubícolas permanentes o temporales de la familias Onuphidae, Spionidae, Magelonidae y Glyceridae. Las playas mostraron variación en su fauna atribuible en ciertos casos a la exposición al oleaje, teniendo menos fauna en las playas más reflectivas. Se mencionan acitivades humanas que pueden explicar la baja riqueza de especies encontrada en algunas de las playas analizadas.

Abstract The diversity and species composition of the intertidal sandy beaches in the southern Pacific coast of Costa Rica were studied by means of cores collected along perpendicular transects to the beaches. The numbers of strictly marine species varied between 5 to 13 taxa, representing an intermediate value compared to those previously reported for these environments in Costa Rica. The isopod Cirolana salvadorensis was the dominant species in the supralittoral zone, whereas polychaete worms belonging to the families Nereididae and Pisionidae dominated the low intertidal zone. Others organisms collected in the beaches were the crabs of the genus Uca, anomurans crabs (Emerita), sand dollars (Mellita longifissa) and several taxa of polychaete tubeworms, such as the Onuphidae, Spionidae, Magelonidae, and Glyceridae. The high faunal difference among the sites is possibly explained by their exposure to the wave energy, with fewer individuals in the more reflective beaches. In addition, human activities might also be responsible for the low infaunal diversity found in some of these beaches. This is the first effort to describe the benthonic fauna of beaches from this area. Rev. Biol. Trop. 63 (Suppl. 1): 273-285. Epub 2015 April 01.

Distribución espacial de Ocypode quadrata (Decapoda: Ocypodidae) en ocho playas de la zona norte oriental de Cuba

Spatial distribution of Ocypode quadrata (Decapoda: Ocypodidae) in eight beaches of NorthEastern Cuba. Studies on the ecology of Ocypode quadrata have been mostly carried out in the Northern and Southern part of its distribution range. In despite that this species is common in Cuban beaches, there are no quantitative studies regarding its abundance and spatial distribution. The aim of this study was to report some aspects about the spatial variation of O. quadrata density in sandy beaches, with different levels of human influence, in the North coast of Eastern Cuba. For this, on May 2010, eight beaches with different levels of human influence were surveyed. On each beach, the number of crabs burrows were counted in 45 quadrats of 4m2 located in three different strata (P1, P2 and P3). According to burrow opening diameter, crabs were separated into young and adults forms. To determine the existence of statistical differences in the density of crab burrows among beaches and strata, a two-way ANOVA was developed with a Scheffé-procedure post hoc test. A total of 355 burrows were counted in 360 sample units. The composition by size classes was 237 burrows for young and 118 for adults. From the total of burrows, 74% were located in P1, 20% in P2 and 6% in P3. The higher concentration of burrows was found at Jiguaní beach (0.52±0.08 burrows/m2) while the lesser concentration was found at Estero Ciego beach (0.06±0.01 burrows/m2). Most of the beaches did not present significant differences in the burrows density (Scheffé, p>0.05), according to ANOVA results, in despite their different human influence level. Density of individuals was significantly higher in the upper intertidal (P1) areas (Scheffé, p<0.05) with predominance of young crabs. Total density diminished in P2 and P3 strata where a predominance of adult individuals was observed. The interaction term of beach and strata evidenced that the pattern of variation among strata was not the same for all beaches. The general pattern of adults and young specimen spatial distribution in the beaches was very similar to those reported in the literature. In the present study, the first conducted in Cuban beaches, we did not find evidence of direct relationship between the level of human impact and the density of ghost crab burrows.

Uno de los organismos más comunes en las playas arenosas son los miembros del género Ocypode conocidos como cangrejos fantasmas, están ampliamente distribuidos en las regiones tropicales y subtropicales; además tienen un importante papel en la transferencia de energía en diferentes niveles tróficos. El objetivo del presente trabajo es dar a conocer aspectos relacionados con la variación espacial de la densidad de O. quadrata en playas con diferente nivel de influencia humana en la costa norte oriental de Cuba. En mayo de 2010, fueron contadas un total de 355 galerías en 360 unidades de muestreo. La composición por clases de tallas fue de 237 galerías de jóvenes y 118 de adultos. Del total de galerías contadas el 74% ocuparon el nivel P1, 20% el nivel P2 y 6% el nivel P3. La densidad varió entre 0.06-0.52galerías/m2. A pesar del nivel de influencia humana, la mayoría de las playas no mostró diferencias significativas en la densidad de galerías (Scheffé, p>0.05). La densidad de individuos en la zona superior de resaca del oleaje es mayor (Scheffé, p<0.05), predominando los jóvenes y en el resto de los estratos la densidad total va disminuyendo y predominan los individuos adultos. El patrón de variación entre los estratos no fue el mismo para todas las playas. En el presente estudio no se encontró evidencia directa entre el nivel de turismo y la densidad de galerías del cangrejo fantasma.

Comunidades vegetales de las transiciones terrestre-acuáticas del páramo de Chingaza, Colombia

Plant communities in the terrestrial-aquatic transition zone in the paramo of Chingaza, Colombia. High Andean paramo ecosystems are an important water resource for many towns, and major cities in this region. The aquatic and wetland vegetation of different paramo lakes, pond, swamps and bogs was studied according to the classical phytosociological approach, which is based on homogenous stands, but excludes any border phenomena or transitional zone. The present research aimed at determining the aquatic and wetland vegetation along different moisture gradients. A total of 89 species in 30 transects were reported, of which Crassula venezuelensis, Carex bonplandii, Callitriche nubigena, Eleocharis macrostachya, Ranunculus flagelliformis, R. nubigenus, Eleocharis stenocarpa, Galium ascendens y Alopecurus aequalis were present in more than one third of the transects. Numerical classification and indicator species analysis resulted in the definition of the next 18 communities: 1) Calamagrostis effusa, 2) Sphagnum cuspidatum, 3) Cyperus rufus, 4) Eleocharis stenocarpa, 5) Carex acutata, 6) Poa annua, 7) Valeriana sp., 8) Ranunculus flagelliformis, 9) Carex bonplandii, 10) Festuca andicola, 11) Muhlenbergia fastigiata, 12) Elatine paramoana, 13) Isoëtes palmeri, 14) Crassula venezuelensis, 15) Lilaeopsis macloviana, 16) Callitriche nubigena, 17) Potamogeton paramoanus and 18) Potamogeton illinoensis. The ordination of communities reveals the presence of three different aquatic-terrestrial gradients which are related to the life form structure of species that characterized the various communities. We concluded that patchiness and heterogeneity of the vegetation is mainly the result of alterations caused by human activities (burning, cattle raise and material extraction for road and dam construction).

La vegetación acuática y semiacuática de los páramos andinos ha sido estudiada generalmente bajo un enfoque fitosociológico tradicional, el cual se basa en muestreos de áreas homogéneas y excluye los fenómenos de borde o transicionales. En el presente estudio se analizó la vegetación acuática y semiacuática del Parque Nacional Natural Chingaza a lo largo de diferentes gradientes hídricos. Asimismo se registran un total de 89 especies en 30 transectos; mediante clasificación numérica y el análisis de especies indicadoras se caracterizan las siguientes 18 comunidades: 1) Calamagrostis effusa, 2) Sphagnum cuspidatum, 3) Cyperus rufus, 4) Eleocharis stenocarpa, 5) Carex acutata, 6) Poa annua, 7) Valeriana sp., 8) Ranunculus flagelliformis, 9) Carex bonplandii, 10) Festuca andicola, 11) Muhlenbergia fastigiata, 12) Elatine paramoana, 13) Isoëtes palmeri, 14) Crassula venezuelensis, 15) Lilaeopsis macloviana, 16) Callitriche nubigena, 17) Potamogeton paramoanus y 18) Potamogeton illinoensis. La ordenación de las comunidades indica la presencia de tres gradientes terrestre-acuáticos diferentes, los cuales se relacionan con las formas de vida de las especies que caracterizan las comunidades. Además se considera que gran parte de la heterogeneidad presentada por la vegetación es el resultado de las alteraciones ambientales generadas por diversas actividades humanas (quemas, ganadería, extracción de material para la construcción de carreteras y la represa).

Longitudinal variation in the composition of the benthic macroinvertebrate fauna of a typical North coast Jamaican river

Benthic macroinvertebrate fauna plays a major role in river ecosystems, especially those of tropical islands. Since there is no information on the distribution of benthic invertebrates along a Jamaican river, we report here on the composition of the benthic fauna of the Buff Bay river, on the Northern coast of Jamaica. A total of 14 samples were collected from five sites, using kick nets and a Surber sampler, between May 1997 and October 1998. We also examined the applicability of the rhithron/potamon model, and some of the premises of the River Continuum Concept (RCC) in relation to the distribution of invertebrate taxa. The results showed a total of 38 taxa of identified invertebrates. A group of dominant taxa, composed mainly of immature stages of insects, occurred at all sites. Two notable characteristics of the river were the absence of a true potamonic fauna and the low representation of the shredder functional feeding group in the community We conclude that, while there was minor variation in the composition of the benthic macroinvertebrate fauna among the sites, this was a response to local conditions within the river system. The characteristics of the community did not conform to either of the models.

La fauna bentónica de macroinvertebrados juega un papel importante en los ecosistemas fluviales, especialmente los de las islas tropicales. En vista de que hay poca información disponible para los ríos de Jamaica, presentamos la composición de la fauna bentónica de la bahía riverina Buff, en la costa norte de Jamaica. Para ello, recolectamos un total de 14 muestras en cinco sitios, mediante el uso de redes de golpe y trampa Surber, entre mayo 1997 y octubre 1998. También se examinó la aplicabilidad del modelo de subdivisión de ríos ritrón/potamón y algunas de las premisas del concepto de Río como un Continuo, en relación con la distribución de los táxones de invertebrados. Los resultados mostraron un total de 38 táxones de invertebrados identificados, hay un grupo de taxones dominantes, compuesto principalmente por los estadios inmaduros de insectos, que se presentaron en todos los sitios. Dos características notables del río fueron la ausencia de una fauna de potamón verdadera y la escasa representación del grupo funcional alimenticio triturador en la comunidad. Llegamos a la conclusión de que, si bien hay una variación de menor importancia en la composición de la fauna de macroinvertebrados bentónicos entre los sitios, esto fue una respuesta a las condiciones locales dentro del sistema fluvial y las características de la comunidad que no se ajusta a ninguno de los modelos. Este estudio representa la primera publicación de una descripción longitudinal de la fauna bentónica de macroinvertebrados de un sistema fluvial de Jamaica.

Comparación temporal de la composición y zonación de organismos en el intermareal rocoso del Parque Nacional Isla del Coco, Pacífico de Costa Rica

Temporal comparison of the composition and zonation of rocky intertidal organisms at Cocos Island National Park, Pacific, Costa Rica. Several biological and physical factors change the rocky shore communities. The desiccation time and the tolerance of the intertidal species produce the vertical zonation. In many studies around the world, a temporal change in this zonation is presented. In Costa Rica, only studies that include temporal trends were carried out in Punta Mala and Montezuma, Pacific coast in 80`s. The rocky intertidal of the Cocos Island National Park, Costa Rica were surveyed photographically. The Chatham bay was sampled in three expeditions (January 2007, October 2007 and April 2008). Photos corresponding to 25x25cm quadrats were taken with the goal to determine diversity and composition differences in rocky shore organisms between sampling dates. The Wafer bay was sampled in January and October 2007. The intertidal of Chatham consists of basaltic rock, while Wafer has basaltic and ignimbrite boulders. The main difference between sites were the higher algae cover (erect-frondose forms) and number of organism bands at Chatham bay. Temporal change was not found in the total cover of sessile fauna and autotrophs. The barnacle Tetraclita stalactifera, that occurs above the algal fringe (lower intertidal), was the invertebrate with the highest coverage. The mobile fauna biodiversity presented no significant trend between sampled months. However, the identity of species, their cover and their abundance showed a moderate temporal change. In October 2007, when the sea surface temperature was 23ºC the infralittoral zone had an increase in green algae cover. The red algae (crust and erect-frondose forms) were dominant in January and April. The pulmonate limpet, Siphonaria gigas and a bacterial biofilm at mid littoral showed a negative association. The snails of the high littoral and the supralittoral zone showed a temporal change in their abundance, but with contrasting patterns between sites. The temporal variation in the assemblages increased from the supralittoral to the infralittoral possibly due to changes in the water temperature and climatic conditions, that could influence the intertidal zone during the high and low tide, respectively. Rev. Biol. Trop. 58 (4): 1387-1403. Epub 2010 December 01.

La zona entre mareas rocoso de las bahías Chatham y Wafer en la Isla del Coco, Costa Rica fueron muestreadas fotográficamente con cuadrículas de 25x25cm en enero y octubre de 2007. Bahía Chatham también se visitó en abril 2008. El intermareal de Chatham estaba constituido por roca basáltica y en Wafer por basalto y cantos rodados de ignimbrita. Las principales diferencias entre sitios fueron las algas con mayor cobetura (erectas-frondosas) y el mayor número de bandas de organismos se dio en Chatham. No se encontró cambio temporal en la cobertura total de fauna sésil y de autótrofos. La mayor cobertura de invertebrados fue la del cirripedio Tetraclita stalactifera, siempre sobre la banda en la zona inferior de las algas. La diversidad de la fauna móvil no presentó tendencia significativa entre los meses de muestreo. Sin embargo, la identidad de las especies, cobertura o abundancia mostró un cambio temporal moderado. En octubre cuando el agua superficial del mar fue baja (23ºC), el infralitoral tuvo un incremento en la cobertura de las algas verdes. La dominancia en enero y abril fue de algas rojas (incrustantes y erectas-frondosas). Las lapas pulmonadas Siphonaria gigas y las cianobacterias del litoral medio mostraron una asociación negativa. Los caracoles de litoral alto y supralittoral presentaron un cambio temporal en su abundancia pero con diferentes patrones entre los sitios. Un incremento de variación en la composición de organismos se dio desde el supralitoral al infralitoral, posiblemente causado por el cambio en las condiciones del agua y el clima, que influyen en la zona entre mareas durante el alta y bajamar, respectivamente.