نتایج جستجو برای: richness

تعداد نتایج: 20745  

2007
Michal Wiezik Marek Svitok Martin Dovčiak

Original oak (Quercus) forests in the southwestern Carpathian Mountains, Slovakia, were replaced by non-forest cover or managed stands often containing introduced non-native tree species. We compared the composition, richness, and abundance of litter-dwelling beetle (Coleoptera) communities in 30 stands across three management types: (i) reserved stands that most closely approximate the pre-cle...

2003
Michael J. Apter Cecilia Au Koenraad Lindner Randall Braman Mitzi Desselles Marie Shelton Stephen Carter George V. Wilson Julie Lee Kathleen A. O'Connell Joseph E. Schwartz Mary M. Gerkovich Marjorie J. Bott Koenraad J. Lindner

s of Conference Papers Conceptual Developments in Reversal Theory Michael J. Apter Georgetown University, Apter International Presenting Author: Michael J. Apter This paper will introduce some new concepts and terms that have been developed recently. These do not contradict any previous tenets of reversal theory, but rather refine some of its central ideas, and provide a vocabulary for describi...

2001
Sanjay Jain Efim B. Kinber Rolf Wiehagen Thomas Zeugmann

Learning of recursive functions refutably means that for every recursive function, the learning machine has either to learn this function or to refute it, i.e., to signal that it is not able to learn it. Three modi of making precise the notion of refuting are considered. We show that the corresponding types of learning refutably are of strictly increasing power, where already the most stringent...

2005
Jani Pellikka Olli Varis Sakari Kuikka Pekka Niemelä

In this thesis I explore the prerequisites for the successful management of wildlife richness in Finnish forests. Wildlife richness is a concept describing species richness and species abundance of well-known game species, which have social, cultural and economical value. The management of wildlife richness is described here as a sequence of actions, where 1) monitoring information of populatio...

2016
Xixi Wang Wenxing Long Brandon S. Schamp Xiaobo Yang Yong Kang Zhixu Xie Menghui Xiong

Vascular epiphytes are important components of biological diversity in tropical forests. We measured the species richness and abundance of vascular epiphytes along four vertical crown zones and five horizontal orientations on 376 trees, as well as the diameter at breast height (DBH) of host trees in tropical cloud forests in Bawangling, Hainan, China. The relationship between vascular epiphyte ...

2007
Michael D. Weiser Brian J. Enquist Brad Boyle Timothy J. Killeen Peter M. Jørgensen Gustavo Fonseca Michael D. Jennings Andrew J. Kerkhoff Abel Monteagudo Percy Núñez Vargas Oliver L. Phillips Nathan G. Swenson Rodolfo Vásquez Martínez

Aim Relationships between range size and species richness are contentious, yet they are key to testing the various hypotheses that attempt to explain latitudinal diversity gradients. Our goal is to utilize the largest data set yet compiled for New World woody plant biogeography to describe and assess these relationships between species richness and range size. Location North and South America. ...

Journal: :Proceedings. Biological sciences 2011
Zhiheng Wang Jingyun Fang Zhiyao Tang Xin Lin

What determines large-scale patterns of species richness remains one of the most controversial issues in ecology. Using the distribution maps of 11 405 woody species in China, we compared the effects of habitat heterogeneity, human activities and different aspects of climate, particularly environmental energy, water-energy dynamics and winter frost, and explored how biogeographic affinities (tr...

Journal: :The American naturalist 2003
Patrick R Stephens John J Wiens

Speciation is the process that ultimately generates species richness. However, the time required for speciation to build up diversity in a region is rarely considered as an explanation for patterns of species richness. We explored this "time-for-speciation effect" on patterns of species richness in emydid turtles. Emydids show a striking pattern of high species richness in eastern North America...

2010
Nicholas J. Gotelli Robert K. Colwell

Measuring species richness is an essential objective for many community ecologists and conservation biologists. The number of species in a local assemblage is an intuitive and natural index of community structure, and patterns of species richness have been measured at both small (e.g. Blake & Loiselle 2000) and large (e.g. Rahbek & Graves 2001) spatial scales. Many classic models in community e...

Journal: :The Quarterly review of biology 2011
John J Wiens

A major goal of research in ecology and evolution is to explain why species richness varies across habitats, regions, and clades. Recent reviews have argued that species richness patterns among regions and clades may be explained by "ecological limits" on diversity over time, which are said to offer an alternative explanation to those invoking speciation and extinction (diversification) and tim...

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