ESTIMATES OF MINIMUM PATCH SIZE DEPEND ON THE METHOD OF ESTIMATION AND THE CONDITION OF THE HABITAT

Ecology ◽  
2007 ◽  
Vol 88 (6) ◽  
pp. 1401-1407 ◽  
Author(s):  
Earl D. McCoy ◽  
Henry R. Mushinsky
Keyword(s):  
Patch Size ◽  
Minimum Patch Size

scholarly journals Satellite mapping of gorse at regional scales

2002 ◽  
Vol 55 ◽  
pp. 95-98 ◽  
Author(s):  
J.D. Shepherd ◽  
W.G. Lee
Keyword(s):  
Spatial Distribution ◽  
Patch Size ◽  
Percent Cover ◽  
Error Assessment ◽  
Mapping Accuracy ◽  
Spectral Bands ◽  
Random Samples ◽  
Minimum Patch Size ◽  
Target Management ◽  
Landsat Satellite

The spatial distribution of gorse in the Wellington Region was mapped using Landsat satellite imagery This satellite is capable of mapping at regional scales (150 000) with a large spatial extent (180 km x 180 km) and has spectral bands in both the visible and infrared parts of the spectrum (6 bands in total) A spring Landsat image distinguished flowering gorse enabling mapping of gorse as a separate scrub type We chose a minimum patch size of 05 ha with a boundary precision of 15 m An error assessment using 1200 stratified random samples across the Wellington region compared the satellite classified result with colour aerial orthophotography and found the mapping accuracy of gorse to be 95 Gorse area by catchment was calculated using an existing GIS of catchment boundaries The area and percent cover of gorse within a catchment is a potential way to target management at regional scales

Landscape attributes determine bobcat (Lynx rufus escuinapae) presence in Central Mexico

Mammalia ◽  
2017 ◽  
Vol 81 (1) ◽  
Author(s):  
María Eugenia Espinosa-Flores ◽  
Carlos A. López-González
Keyword(s):  
Patch Size ◽  
Camera Traps ◽  
Lynx Rufus ◽  
Tree Cover ◽  
Central Mexico ◽  
Anthropogenic Pressure ◽  
Landscape Characteristics ◽  
Breeding Populations ◽  
Minimum Patch Size

AbstractCentral Mexico has experienced a decline of its natural vegetation due to anthropogenic pressure. In 12 sites in the southeastern portion of Guanajuato, we deployed camera traps and analyzed landscape characteristics. We recorded the presence of bobcats in four sites. Their presence was explained by a combination of patch size and tree cover. Because bobcats are sensitive to fragmentation and habitat loss, it is essential to increase sampling and conservation efforts to define the minimum patch size and maximum area of human development that can limit their long-term persistence and the establishment of breeding populations.

Evidence of a Minimum Patch Size Threshold of Reproductive Success in an Endangered Songbird

2010 ◽  
Vol 74 (1) ◽  
pp. 133-139 ◽  
Author(s):  
Jerrod A. Butcher ◽  
Michael L. Morrison ◽  
Dean Ransom ◽  
R. Douglas Slack ◽  
R. Neal Wilkins
Keyword(s):  
Reproductive Success ◽  
Patch Size ◽  
Minimum Patch Size ◽  
Size Threshold

Conditional persistence in logistic models via nonlinear diffusion

2002 ◽  
Vol 132 (2) ◽  
pp. 267-281 ◽  
Author(s):  
Robert Stephen Cantrell ◽  
Chris Cosner
Keyword(s):  
Diffusion Process ◽  
Nonlinear Diffusion ◽  
Patch Size ◽  
Logistic Models ◽  
Threshold Effect ◽  
Small Population ◽  
Process Models ◽  
Logistic Equations ◽  
Minimum Patch Size ◽  
Parameter Ranges

A nonlinear diffusion process modelling aggregative dispersal is combined with local (in space) population dynamics given by a logistic equation and the resulting growth-dispersal model is analysed. The nonlinear diffusion process models aggregation via a diffusion coefficient, which is decreasing with respect to the population density at low densities. This mechanism is similar to area-restricted search, but it is applied to conspecifics rather than prey. The analysis shows that in some cases the models predict a threshold effect similar to an Allee effect. That is, for some parameter ranges, the models predict a form of conditional persistence where small populations go extinct but large populations persist. This is somewhat surprising because logistic equations without diffusion or with non-aggregative diffusion predict either unconditional persistence or unconditional extinction. Furthermore, in the aggregative models, the minimum patch size needed to sustain an existing population at moderate to high densities may be smaller than the minimum patch size needed for invasibility by a small population. The tradeoff is that if a population is inhabiting a large patch whose size is reduced below the size needed to sustain any population, then the population on the patch can be expected to experience a sudden crash rather than a steady decline.

Habitat fragmentation causes collapse of kelp recruitment

2020 ◽  
Vol 648 ◽  
pp. 111-123
Author(s):  
C Layton ◽  
MJ Cameron ◽  
M Tatsumi ◽  
V Shelamoff ◽  
JT Wright ◽  
...  
Keyword(s):  
Habitat Fragmentation ◽  
Patch Size ◽  
Life Stage ◽  
Extended Period ◽  
Anthropogenic Disturbances ◽  
Anthropogenic Sources ◽  
Kelp Forests ◽  
Natural Disturbances ◽  
Short Term ◽  
Turf Algae

Kelp forests in many regions are experiencing disturbance from anthropogenic sources such as ocean warming, pollution, and overgrazing. Unlike natural disturbances such as storms, anthropogenic disturbances often manifest as press perturbations that cause persistent alterations to the environment. One consequence is that some kelp forests are becoming increasingly sparse and fragmented. We manipulated patch size of the kelp Ecklonia radiata over 24 mo to simulate persistent habitat fragmentation and assessed how this influenced the demography of macro- and microscopic juvenile kelp within the patches. At the beginning of the experiment, patch formation resulted in short-term increases in E. radiata recruitment in patches <1 m2. However, recruitment collapsed in those same patches over the extended period, with no recruits observed after 15 mo. Experimental transplants of microscopic and macroscopic juvenile sporophytes into the patches failed to identify the life stage impacted by the reductions in patch size, indicating that the effects may be subtle and require extended periods to manifest, and/or that another life stage is responsible. Abiotic measurements within the patches indicated that kelp were less able to engineer the sub-canopy environment in smaller patches. In particular, reduced shading of the sub-canopy in smaller patches was associated with proliferation of sediments and turf algae, which potentially contributed to the collapse of recruitment. We demonstrate the consequences of short- and longer-term degradation of E. radiata habitats and conclude that habitat fragmentation can lead to severe disruptions to kelp demography.

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