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Utilization distribution as a predictor in modeling black rhino (Diceros bicornis) habitat in Africa's southern Rift Valley
Title
Utilization distribution as a predictor in modeling black rhino (Diceros bicornis) habitat in Africa's southern Rift Valley.
Creator
van der Heiden, Craig., Florida Atlantic University, Volin, John C.
Abstract/Description
An innovative technique of evaluating resource selection for black rhino (Diceros bicornis) was used to assess the population utilization distribution (PUD) within a rhino sanctuary in Liwonde National Park, Malawi. The PUD enabled an evaluation of responses to habitat variables over a spatial gradient of resource selection. A Geographic Information System (GIS) was constructed using vegetation, browse availability, roads, rivers, water holes and satellite imagery. Linear models were...
Show moreAn innovative technique of evaluating resource selection for black rhino (Diceros bicornis) was used to assess the population utilization distribution (PUD) within a rhino sanctuary in Liwonde National Park, Malawi. The PUD enabled an evaluation of responses to habitat variables over a spatial gradient of resource selection. A Geographic Information System (GIS) was constructed using vegetation, browse availability, roads, rivers, water holes and satellite imagery. Linear models were developed to quantify habitat variables within the black rhino sanctuary and park. The sanctuary model was calibrated within a known core area (R^2=0.42, P<0.001), validated in a second area (R^2=0.56, P<0.001) within the sanctuary and, subsequently, used to predict potential black rhino habitat within the remaining sanctuary boundaries. The model for the entire Liwonde National Park predicted additional black rhino habitat (R^2=0.25, P<0.05). Population utilization distribution was found to be a powerful conservation tool for determining suitable black rhino habitat.
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Date Issued
2005
PURL
http://purl.flvc.org/fcla/dt/13296
Subject Headings
Habitat selection--Statistical methods, Liwonde National Park (Malawi), Rift Valley Province (Kenya), Wildlife conservation--Africa, Habitat (Ecology)
Format
Document (PDF)
The enigmatic Marmorkrebs (marbled crayfish) is the parthenogenetic form of Procambarus fallax (Hagen, 1870)
Title
The enigmatic Marmorkrebs (marbled crayfish) is the parthenogenetic form of Procambarus fallax (Hagen, 1870).
Creator
Peer Martin, Nathan J. Dorn, Tadashi Kawai, Craig van der Heiden, Gerhard Scholtz
Abstract/Description
A mysterious parthenogenetic cambarid crayfish (the Marmorkrebs) has been spreading across the globe for the past decade. We compare this crayfish directly to two other cambarids, Procambarus fallax and P. alleni, that have been suggested to be related or even identical to the Marmorkrebs. Using external morphology and sequences of two mitochondrial genes we show clear correspondences between Marmorkrebs and P. fallax, a species found natively throughout peninsular Florida, USA. Based on...
Show moreA mysterious parthenogenetic cambarid crayfish (the Marmorkrebs) has been spreading across the globe for the past decade. We compare this crayfish directly to two other cambarids, Procambarus fallax and P. alleni, that have been suggested to be related or even identical to the Marmorkrebs. Using external morphology and sequences of two mitochondrial genes we show clear correspondences between Marmorkrebs and P. fallax, a species found natively throughout peninsular Florida, USA. Based on these congruent results we suggest that the Marmorkrebs is the parthenogenetic form of P. fallax. This finding has potential evolutionary and ecological implications at several levels. The Marmorkrebs might be a type of geographical parthenogenesis, but a natural population in the wild is so far unknown. Furthermore, challenges arise in regard to the respective species status of the Marmorkrebs. Taxonomically we suggest that the Marmorkrebs is treated as ‘parthenogenetic form’ of P. fallax. Last but not least, the identity of this animal and its ecology has an impact for considering potential spread and effects of this species across the globe.
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Date Issued
2010
PURL
http://purl.flvc.org/fau/fd/FAUIR000482
Format
Document (PDF)
Population distribution, habitat selection, and life history of the slough crayfish (Procambarus fallax) in the ridge-slough landscape of the central Everglades
Title
Population distribution, habitat selection, and life history of the slough crayfish (Procambarus fallax) in the ridge-slough landscape of the central Everglades.
Creator
Van der Heiden, Craig., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
Understanding where and why organisms are distributed in the environment are central themes in ecology. Animals live in environments in which they are subject to competing demands, such as the need to forage, to find mates, to reproduce, and to avoid predation. Optimal habitats for these various activities are usually distributed heterogeneously in the landscape and may vary both spatially and temporally, causing animals to adjust their locations in space and time to balance these conflicting...
Show moreUnderstanding where and why organisms are distributed in the environment are central themes in ecology. Animals live in environments in which they are subject to competing demands, such as the need to forage, to find mates, to reproduce, and to avoid predation. Optimal habitats for these various activities are usually distributed heterogeneously in the landscape and may vary both spatially and temporally, causing animals to adjust their locations in space and time to balance these conflicting demands. In this dissertation, I outline three studies of Procambarus fallax in the ridge-slough landscape of Water conservation Area 3A (WCS-3A). The first section outlines an observational sampling study of crayfish population distribution in a four hectare plot, where I statistically model the density distribution at two spatial scales. ... Secondly, I use radio telemetry to study individual adult crayfish movements at two study sites and evaluate habitat selection using Resource Selection Functions. In the third section, I test the habitat selection theory, ideal free distribution, by assessing performance measures (growth and mortality) of crayfish in the two major vegetation types in a late wet season (November 2007) and early wet season (August 2009).
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Date Issued
2012
PURL
http://purl.flvc.org/FAU/3356890
Subject Headings
Habitat selection, Statistical methods, Fish habitat improvement, Crayfish, Life cycles, Wetland ecology, Habitat (Ecology)
Format
Document (PDF)