نتایج جستجو برای: ecological niche

تعداد نتایج: 118276  

2012
Sharon A. Cantrell Lisabeth Duval-Pérez

Fungi were documented in tropical hypersaline microbial mats and their role in the degradation of complex carbohydrates (exopolymeric substance - EPS) was explored. Fungal diversity is higher during the wet season with Acremonium, Aspergillus, Cladosporium, and Penicillium among the more common genera. Diversity is also higher in the oxic layer and in young and transient mats. Enrichments with ...

2015
Guinevere O U Wogan Jonathan Q Richmond

Adaptation to different thermal environments has the potential to cause evolutionary changes that are sufficient to drive ecological speciation. Here, we examine whether climate-based niche divergence in lizards of the Plestiodon skiltonianus species complex is consistent with the outcomes of such a process. Previous work on this group shows that a mechanical sexual barrier has evolved between ...

2016
Wilbert T. Kadye Albert Chakona Martine S. Jordaan

Ecological niche theory predicts that coexistence is facilitated by resource partitioning mechanisms that are influenced by abiotic and biotic interactions. Alternative hypotheses suggest that under certain conditions, species may become phenotypically similar and functionally equivalent, which invokes the possibility of other mechanisms, such as habitat filtering processes. To test these hypot...

Journal: :Ecology and evolution 2016
Jessica J Scriven Penelope R Whitehorn Dave Goulson Matthew C Tinsley

Competition theory states that multiple species should not be able to occupy the same niche indefinitely. Morphologically, similar species are expected to be ecologically alike and exhibit little niche differentiation, which makes it difficult to explain the co-occurrence of cryptic species. Here, we investigated interspecific niche differentiation within a complex of cryptic bumblebee species ...

2014
Ben Wielstra Jan W. Arntzen

If potential morphologically cryptic species, identified based on differentiated mitochondrial DNA, express ecological divergence, this increases support for their treatment as distinct species. However, mitochondrial DNA introgression hampers the correct estimation of ecological divergence. We test the hypothesis that estimated niche divergence differs when considering nuclear DNA composition ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2009
Elizabeth A Hadly Paula A Spaeth Cheng Li

Traits that enable species to persist in ecological environments are often maintained over time, a phenomenon known as niche conservatism. Here we argue that ecological niches function at levels above species, notably at the level of genus for mammals, and that niche conservatism is also evident above the species level. Using the proxy of geographic range size, we explore changes in the realize...

Journal: :International Journal of Health Geographics 2009
Rebecca S Levine Krista L Yorita Matthew C Walsh Mary G Reynolds

BACKGROUND Ecological niche modeling is a method for estimation of species distributions based on certain ecological parameters. Thus far, empirical determination of significant differences between independently generated distribution maps for a single species (maps which are created through equivalent processes, but with different ecological input parameters), has been challenging. RESULTS W...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2012
Patricio Jeraldo Maksim Sipos Nicholas Chia Jennifer M Brulc A Singh Dhillon Michael E Konkel Charles L Larson Karen E Nelson Ani Qu Lawrence B Schook Fang Yang Bryan A White Nigel Goldenfeld

The theoretical description of the forces that shape ecological communities focuses around two classes of models. In niche theory, deterministic interactions between species, individuals, and the environment are considered the dominant factor, whereas in neutral theory, stochastic forces, such as demographic noise, speciation, and immigration, are dominant. Species abundance distributions predi...

Journal: :محیط زیست طبیعی 0
فرهاد عطایی کارشناس ارشد زیستگاه ها و تنوع زیستی، دانشکده محیط زیست و انرژی، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، ایران محمود کرمی استاد گروه محیط زیست، دانشکده محیط زیست و انرژی، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، ایران محمد کابلی استادیار گروه محیط زیست، دانشکده منابع طبیعی، دانشگاه تهران، ایران

brown bear (ursus arctos) is one of the most important carnivores in iran. however, information on its habitat associations is scared. based on ecological niche factor analysis (enfa) method, a summer habitat suitability model was developed for this species in the southern part of alborz protected area. our results showed that, brown bears prefer higher altitudes and northern aspects in their p...

A.R. Mirzajani, B. Kiabi S.A. Nezami

In the present study, some ecological factors were studied for Amphipoda at different depths. The Shannon, Margalef, and Hill indices were used to determine the  species diversity, richness and evenness, respectively. In addition, the association and niche overlap values were estimated. Indices of species richness and diversity were highest at 50 and 100m depths, respectively.  The ordination o...

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