Résumé
We performed a scientometry to validate trends in the scientific production on phytotelmata and the importance of these microenvironments in the maintenance of biodiversity. We searched for articles in the Web of Science and looked at publications from 1987 to 2016. We collected years of publication, surveyed organisms, countries where the surveys took place, plants that accumulate phytotelmata, scientific journals that publish more about the topic and their respective IFs (Impact Factor) and the keywords of each article. We built a heatmap using the most frequent keywords in the studies, to investigate the topics studied over the years. We have found 293 publications, increasing over the years. Insects, anurans and crustaceans were the most studied organisms. The most studied plant families were Bromeliaceae, Poaceae and Apiaceae. The published studies analized were carried out mainly in Brazil, Argentina and Peru. The most published journals on the subject are: Zootaxa, Hydrobiologia, Biotropica and Journal of Natural History. Some main global concerns such as climate change, habitat fragmentation has gained the attention of the phytotelmata studies in the recent years. The results contribute to the knowledge about phytotelmata accumulated biodiversity and research trends.
Realizamos uma cienciometria para demonstrar tendências na produção científica sobre fitotelmata e a importância desses microambientes na manutenção da biodiversidade. Buscamos artigos no Web of Science e analisamos publicações de 1987 até 2016. Coletamos os anos de publicação, organismos estudados, países onde ocorreram as pesquisas, plantas que acumulam fitotelmata, revistas científicas que mais publicam sobre o tema e seus respectivos FIs (Fator de Impacto) e as palavras-chave de cada artigo. Fizemos um heatmap, utilizando as palavras-chave mais frequentes nos estudos, para investigar os tópicos estudados ao longo dos anos. Encontramos 293 publicações, com aumento ao longo dos anos. Os insetos, anuros e crustáceos foram os organismos mais estudados. As famílias de plantas mais estudadas foram Bromeliaceae, Poaceae e Apiaceae. As pesquisas foram realizadas, principalmente, no Brasil, na Argentina e no Peru. Os periódicos que mais publicam sobre o tema são: Zootaxa, Hydrobiologia, Biotropica e Journal of Natural History. Os resultados contribuem para o conhecimento sobre a biodiversidade acumulada em fitotelmata e tendências nas pesquisas.
Sujets)
Biodiversité , Développement Technologique et Recherche Scientifique , Publications pour Diffusion Scientifique , BromeliaRésumé
The spatial distribution of individuals is a fundamental property of most species and constitutes essential information for the development of restoration and conservation strategies, especially for endangered plant species. In this paper we describe the spatial distribution of different size classes of the endangered tropical tree Guaiacum sanctum and the effect of canopy cover on spatial aggregation. Adult G. sanctum were located and mapped in a 50ha plot in Palo Verde National Park, Costa Rica. Seedlings, saplings and juveniles were mapped to the nearest centimetre and permanently marked in three 50x50m subplots. Within each subplot spatial aggregation was assessed using Ripley’s K statistic and canopy opening readings were performed every 5m using a densitometer. Kriging spatial interpolation and Monte Carlo simulations were used to determine if average canopy cover differed among size classes. Individuals of G. sanctum were spatially aggregated at all size classes with seedlings being the most frequent size class in all subplots. Seedlings were found predominantly in areas with significantly higher canopy cover. In contrast, juveniles were more likely found in areas with higher light availability. The high number of seedlings, saplings, and juveniles relative to adults suggests that populations of G. sanctum in PVNP are expanding. Light availability and canopy structure are important factors shaping the spatial distribution of this species. The contemporary demographic structure of G. sanctum is dependent on forest gap dynamics and changes in human disturbance during the past 25 years.
La distribución espacial es una característica fundamental de las especies y es importante para el desarrollo de estrategias de conservación y manejo. Aquí presentamos la distribución espacial de varias etapas de desarrollo del árbol tropical Guaiacum sanctum, una especie en vías de extinción. Todos los adultos de G. sanctum se geo-referenciaron en una parcela de 50ha en el Parque Nacional Palo Verde. Las plántulas, los briznales y juveniles se mapearon en tres sub-parcelas de 50x50m. En cada sub-parcela se estimó la agregación espacial de los individuos mediante la K de Ripley. Observamos que los individuos de G. sanctum se encuentran siempre agregados, sin importar en que etapa de desarrollo se encuentren. Registramos la apertura del dosel cada 5m con un densiómetro y mediante una extra-polación espacial (Krigin) determinamos que las plántulas se agregan con mayor frecuencia en áreas con abundante cobertura de dosel, mientras que es más probable encontrar juveniles agregados en áreas con una mayor incidencia de luz. Las plántulas son los individuos más abundantes, esta distribución de edades nos sugiere que esta población probablemente está en expansión. Concluimos que el régimen lumínico y la cobertura de dosel son factores que afectan significativamente la distribución espacial del Guayacán Real.