Uses and Requirements of Ecological Niche Models and Related Distributional Models

Abstract.—Modeling approaches that relate known occurrences of species to landscape features to discover ecological properties and predict geographic occurrences have seen extensive recent application in ecology, systematics, and conservation. A key component in this process is estimation or characterization of species’ distributions in ecological space, which can then be useful in understanding their potential distributions in geographic space. Hence, this process is often termed ecological niche modeling or (less boldly) species distribution modeling. Applications of this approach vary widely in their aims, products, and requirements; this variety is reviewed herein, examples are provided, and differences in data needs and possible interpretations are discussed

Mechanistic and Correlative Models of Ecological Niches

The suite of factors that drives where and under what conditions a species occurs has become the focus of intense research interest. Three general categories of methods have emerged by which researchers address questions in this area: mechanistic models of species’ requirements in terms of environmental conditions that are based on first principles of biophysics and physiology, correlational models based on environmental associations derived from analyses of geographic occurrences of species, and process-based simulations that estimate occupied distributional areas and associated environments from assumptions about niche dimensions and dispersal abilities. We review strengths and weaknesses of these sets of approaches, and identify significant advantages and disadvantages of each. Rather than identifying one or the other as ‘better,’ we suggest that researchers take great care to use the method best-suited to each specific research question, and be conscious of the weaknesses of any method, such that inappropriate interpretations are avoided

Interpretation of Models of Fundamental Ecological Niches and Species’ Distributional Areas

Ecological niche modeling?that is, estimation of the dimensions of fundamental ecological niches of species?to predict their geographic distributions is increasingly being employed in systematics, ecology, conservation, public health, etc. This technique is often (of necessity) based on data comprising records of presences only. In recent years, many modeling approaches have been devised to estimate these interrelated expressions of a species’ ecology, distributional biology, and evolutionary history?nevertheless, in many cases, a formal basis in ecological and evolutionary theory has been lacking. In this paper, we outline such a formal basis for the suite of techniques that can be termed ‘ecological niche modeling,’ analyze example situations that can be modeled using these techniques, and clarify the interpretation of results

Completeness of Digital Accessible Knowledge of the Plants of Ghana

Providing comprehensive, informative, primary, research-grade biodiversity information represents an important focus of biodiversity informatics initiatives. Recent efforts within Ghana have digitized >90% of primary biodiversity data records associated with specimen sheets in Ghanaian herbaria; additional herbarium data are available from other institutions via biodiversity informatics initiatives such as the Global Biodiversity Information Facility. However, data on the plants of Ghana have not as yet been integrated and assessed to establish how complete site inventories are, so that appropriate levels of confidence can be applied. In this study, we assessed inventory completeness and identified gaps in current Digital Accessible Knowledge (DAK) of the plants of Ghana, to prioritize areas for future surveys and inventories. We evaluated the completeness of inventories at ½° spatial resolution using statistics that summarize inventory completeness, and characterized gaps in coverage in terms of geographic distance and climatic difference from well-documented sites across the country. The southwestern and southeastern parts of the country held many well-known grid cells; the largest spatial gaps were found in central and northern parts of the country. Climatic difference showed contrasting patterns, with a dramatic gap in coverage in central-northern Ghana. This study provides a detailed case study of how to prioritize for new botanical surveys and inventories based on existing DAK

Tree Trunk Arthropod Faunas as Food Resources for Birds

Author Institution: Department of Zoology, Miami UniversityThe composition, abundance, and relationship to trunk-surface characteristics of the tree-trunk surface arthropod fauna were studied from August, 1984 to January, 1985 in a beech-maple forest in southwestern Ohio. Samples of trunk-surface arthropods were taken monthly from American beech and sugar maple trees. Although resource levels on the two tree species did not differ significantly, arthropod resource levels were dynamic, changing monthly in magnitude and composition. Live arthropods became progressively less abundant as winter approached; non-living/dormant items did not. Results suggest that trunk surface characteristics offer foraging birds few reliable clues about arthropod resource levels

ENVIRONMENTAL CORRELATION STRUCTURE AND ECOLOGICAL NICHE MODEL PROJECTIONS

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Global Invasive Potential of 10 Parasitic Witchweeds and Related Orobanchaceae

The plant family Orobanchaceae includes many parasitic weeds that are also impressive invaders and aggressive crop pests with several specialized features (e.g. microscopic seeds, parasitic habits). Although they have provoked several large-scale eradication and control efforts, no global evaluation of their invasive potential is as yet available. We use tools from ecological niche modeling in combination with occurrence records from herbarium specimens to evaluate the global invasive potential of each of 10 species in this assemblage, representing several of the worst global invaders. The invasive potential of these species is considerable, with all tropical and subtropical countries, and most temperate countries, vulnerable to invasions by one or more of them.I do not have complete information on funding. The work was probably supported by a Department of Defense (USA) grant to Town Peterson. RAJW was supported by US National Science Foundation (Ref: KUCR 31000)

Botanical Sampling Gaps Across the Cameroon Mountains

With the emergence of a new field, biodiversity informatics, an important task has been to evaluate completeness of biodiversity information that is existing and available for various countries and regions. This paper offers a first and very basic assessment of sampling gaps and inventory completeness across the Cameroon Mountains. Because digital accessible knowledge is severely limited for the region, we relied on qualitative evaluations of inventory completeness, supplemented by large amounts of data from the National Herbarium of Cameroon (YA) database. Detailed botanical inventories have been developed for Mt Cameroon, the Kupe-Mwanenguba Mountains, Mt Oku, and the Mambila Plateau, leaving substantial geographic and environmental coverage gaps corresponding to Rumpi Hills, Mt Nlonako, Kimbi Fungom National Park, Bali and Bafut Ngemba, Mt Bamboutos, Kagwene, and Tchabal Mbabo. This paper provides a roadmap for a comprehensive botanical survey for this region. Completing this survey plan, the resulting data will allow researchers to track changes in biodiversity and identify priority areas for conservation on the various mountain ranges that make up this important biodiversity hotspot

Avian influenza infections in non-migratant land birds in Andean Peru

As part of ongoing surveillance for avian influenza viruses (AIV) in Peruvian birds, in June 2008, we sampled 600 land birds of 177 species, using real-time reverse-transcription PCR. We addressed the assumption that AIV prevalence is low or nil among land birds, a hypothesis that was not supported by the results—rather, we found AIV infections at relatively high prevalences in birds of the orders Apodiformes (hummingbirds) and Passeriformes (songbirds). Surveillance programs for monitoring spread and identification of AIV should thus not focus solely on water birds.We thank ornithologists Michael Andersen, Roger Boyd, Adolfo Navarro-Siguenza, Luis Sanchez-Gonzalez, and Mark Robbins; the staff of CORBIDI, Lima, Peru, for extensive assistance with logistics associated with field sampling of birds; M. Papes¸ for assistance with maps; and A. E. Gonzalez for extending facilities and hospitality at the School of Veterinary Medicine, Universidad Nacional. Mayor de San Marcos. The study was funded by the National Institutes of Health–Fogarty International Center, US Department of Defense AFHSC-GEIS grant GF0121_07_LI, and R.A.J.W. was supported by grant CGL2010-15734/BOS, Ministerio de Ciencia e Innovacion, Spain, and a Tinker Field Research grant

Geographic Variation in the Ontogeny of Beak Coloration of Gray-Breasted Jays (Aphelocoma ultramarina)

No abstract is available for this item