Movement behaviour of adult western toads in a fragmented, forest landscape

2009 ◽  
Vol 87 (12) ◽  
pp. 1184-1194 ◽  
Author(s):  
Isabelle Deguise ◽  
John S. Richardson
Keyword(s):  
Forest Harvesting ◽  
Habitat Modification ◽  
Small Scale ◽  
Fragmented Landscape ◽  
Forest Patches ◽  
Movement Rates ◽  
Fragmented Forest ◽  
Fitness Consequences ◽  
Western Toads ◽  
Anaxyrus Boreas

Habitat loss and fragmentation are among the best documented explanations for the dramatic declines amphibians are experiencing globally. The western toad ( Anaxyrus boreas (Baird and Girard, 1852)) is an IUCN red-listed species whose distribution range has been significantly affected by habitat modification. We used radiotelemetry to follow daily, postbreeding movement patterns of 23 adult male toads in a fragmented landscape near Vancouver, British Columbia, Canada, composed of forest patches and small, recent clearcuts (~5 ha). Results showed that toads in forests oriented towards edges of clearcuts from at least as far as 150 m. Greater than 60% of toads released in forest patches chose to enter the clearcuts from adjacent forests, indicating high boundary permeability. Net displacement distance was not significantly reduced in these clearcuts; however, movement rates were significantly lower on clearcuts than in forest. This indicates that there is no structural impediment to movements; however, there still could be fitness consequences or an interaction with summer weather. Toads also used roads for their movement more frequently than at random relative to their area. These results suggest that the western toad’s movements may not be negatively affected by small-scale forest harvesting at our latitude during the spring.

Influence of patch- and landscape-level attributes on the movement behavior of raccoons in agriculturally fragmented landscapes

2010 ◽  
Vol 88 (2) ◽  
pp. 161-169 ◽  
Author(s):  
J. C. Beasley ◽  
O. E. Rhodes
Keyword(s):  
Home Range ◽  
Home Range Size ◽  
Range Size ◽  
Habitat Characteristics ◽  
Movement Behavior ◽  
Home Ranges ◽  
Fragmented Landscape ◽  
Forest Patches ◽  
Movement Rates ◽  
Landscape Level

We tested the hypotheses that movement rates and home range sizes of raccoons ( Procyon lotor (L., 1758)) inhabiting a highly fragmented landscape would vary in response to local and landscape-level habitat characteristics. Raccoons occupying small forest patches containing limited water sources maintained larger home ranges than raccoons with home ranges established in large forest patches containing abundant sources of water. Raccoons occupying large (>25 ha) forest patches exhibited minimal interindividual variance in home range size compared with raccoons monitored in patches <25 ha. This differing pattern of variance in home range size suggests that critical resources were more widely dispersed within and among small patches, forcing raccoons occupying smaller patches to utilize larger and more spatially disparate areas to satisfy their metabolic and reproductive needs. Movement rates of raccoons were positively related to home range size, although movement rates of males (246.9 m/h) exceeded those of females (188.3 m/h). Moreover, movements of male raccoons primarily were concentrated along forest–agriculture interfaces, whereas female movements were concentrated in forest interiors. Our results indicate that raccoons have modified their movement behavior in agricultural ecosystems in response to the discontinuous nature of resources and suggest that the extent of raccoon space use in these ecosystems is strongly influenced by the availability of non-agricultural resources.

Enter the Matrix: Use of Secondary Matrix by Mouse Lemurs

2020 ◽  
pp. 1-11
Author(s):  
Travis S. Steffens ◽  
Malcolm S. Ramsay ◽  
Bertrand Andriatsitohaina ◽  
Ute Radespiel ◽  
Shawn M. Lehman
Keyword(s):  
Relative Abundance ◽  
Mouse Lemur ◽  
Primate Species ◽  
Forest Loss ◽  
Fragmented Landscape ◽  
Forest Fragments ◽  
Matrix Elements ◽  
Fragmented Forest ◽  
Mouse Lemurs ◽  
The Matrix

Madagascar is home to many threatened and endemic primate species, yet this island has seen dramatic declines in lemur habitat due to forest loss. This forest loss has resulted in an increasingly fragmented forest landscape, with fragments isolated from each other by grasslands (i.e., matrix). The grassland matrix is not entirely homogeneous containing matrix elements such as isolated trees and shrubs and linear features such as drainage lines. Because most lemurs are predominantly arboreal, they may preferentially use matrix elements to facilitate dispersal between fragments for access to mates or reduce feeding competition, allowing gene flow between fragments of habitat. Therefore, it is important to understand to what degree they use the matrix. We investigated matrix use in two mouse lemurs, the grey mouse lemur (<i>Microcebus murinus</i>) and the golden-brown mouse lemur (<i>Microcebus ravelobensis</i>) in a fragmented landscape in northwest Madagascar. We tested the predictions that: (1) lemurs use matrix less often than forest fragments, (2) if they use the matrix, then they will preferentially use matrix elements compared to grassland, and (3) <i>M. murinus</i> will disperse into the matrix further than <i>M. ravelobensis</i>. In 2011, we visually surveyed line transects in four areas containing matrix elements and four adjacent forest fragments during nocturnal walks. In 2017, we set up traplines in four areas of the matrix containing matrix elements, three areas that were grassland, and six traplines in adjacent fragments. We compared the relative abundance of mouse lemurs in matrix transects to fragmented forest transects, and the relative abundance of captured lemurs in matrix elements, grassland, and fragment traplines. We found that encounter rates of mouse lemurs did not significantly differ between the matrix and fragmented forest transects or traplines. Our sample size was too low to determine if the mean distance from the forest was greater for either <i>Microcebus</i> spp. Our study highlights that mouse lemurs do use matrix elements and there may be interspecific differences in use. Further research is needed to confirm species-specific matrix use, why mouse lemurs use matrix, and how much matrix elements facilitate movement for each species in fragmented landscapes.

scholarly journals Domestic dogs in a fragmented landscape in the Brazilian Atlantic Forest: abundance, habitat use and caring by owners

2010 ◽  
Vol 70 (4) ◽  
pp. 987-994 ◽  
Author(s):  
PC. Torres ◽  
PI. Prado
Keyword(s):  
Atlantic Forest ◽  
Domestic Dogs ◽  
Domestic Dog ◽  
Fragmented Landscape ◽  
Brazilian Atlantic Forest ◽  
Forest Patches ◽  
Forest Patch ◽  
Questionnaire Surveys ◽  
Responsible Ownership ◽  
Patch Edge

This study aimed at estimating the population size and attitudes of residents towards caring for domestic dogs, through questionnaire surveys, as well as the frequency of these animals in different habitats (anthropic and forest patch), using scent stations. The study was conducted in a severely fragmented area of the Brazilian Atlantic Forest. A large number of unrestricted dogs was recorded, averaging 6.2 ind/km². These dogs have owners and are regularly fed. Dog records decreased from the anthropogenic matrix to the forest patch edge, which suggests that dogs act as an edge effect on forest patches. Encounters between domestic dog and wild animals can still be frequent in severely fragmented landscapes, mainly at the forest edges. However the fact that most dogs have an owner and are more frequent in the anthropic habitat suggests that their putative effects are less severe than expected for a carnivore of such abundance, but the reinforcement of responsible ownership is needed to further ameliorate such effects.

Observations on the aggregation of adult cicadas (Homoptera: Cicadidae) in tropical forests

1980 ◽  
Vol 58 (5) ◽  
pp. 711-722 ◽  
Author(s):  
Allen M. Young
Keyword(s):  
Tropical Forests ◽  
Tree Species ◽  
Secondary Forest ◽  
Life Cycles ◽  
Direct Sunlight ◽  
Patchy Distribution ◽  
Forest Patches ◽  
Feeding Sites ◽  
Fragmented Forest ◽  
Forest Habitats

The distribution of adult cicadas in various tree species was studied in Costa Rica. These observations indicate that tropical cicadas, mostly males, often congregate in certain tree species in various kinds of secondary forest habitats. Aggregated male cicadas exhibit intense chorusing and females fly into chorusing aggregations, presumably for mating. Trees used for aggregations are also cicada feeding sites. The conspicuous absence of oviposition evidence or nymphal skins suggest that these trees are used primarily for intensive male chorusing which assembles females for mating. Tendency to congregate in particular trees is related to the spatial position of the trees and their exposure to direct sunlight. Highly fragmented forest patches in some regions (central highlands, lowland Guanacaste) function as islands for cicadas to complete their life cycles and mating, whereas the abundant secondary forest habitats in other regions (northeastern lowlands) are being invaded by a few species which use secondary forest trees for completion of life cycles and mating. The apparent absence of dense aggregations of adult cicadas within climax tropical forests, even though nymphal skins are found here, is probably related to the very patchy distribution of individuals of each tree species and perhaps other factors (i.e., shading) affecting the attractiveness of trees for congregating cicadas.

The role of size and number of forest patches in the conservation of bird species in a fragmented landscape

Ostrich ◽  
2020 ◽  
Vol 91 (4) ◽  
pp. 292-298
Author(s):  
Kwaku Brako Dakwa ◽  
Bright Opoku ◽  
Judith Toku
Keyword(s):  
Bird Species ◽  
Fragmented Landscape ◽  
Forest Patches

Bird assemblages in isolated Ficus trees in Kenyan farmland

2006 ◽  
Vol 22 (6) ◽  
pp. 723-726 ◽  
Author(s):  
G. W. Eshiamwata ◽  
D. G. Berens ◽  
B. Bleher ◽  
W. R. J. Dean ◽  
K. Böhning-Gaese
Keyword(s):  
Tropical Forests ◽  
Forest Fragmentation ◽  
Seedling Establishment ◽  
Agricultural Land ◽  
Agricultural Landscapes ◽  
Forest Patches ◽  
Frugivorous Birds ◽  
Fragmented Forest ◽  
Important Group ◽  
Disturbed Areas

Over the last few decades a rapid and extensive conversion of tropical forests to agricultural land has taken place resulting in mosaics of fragmented forest patches, pastures and farmland. While the effects of forest fragmentation on biodiversity have been intensively studied within the remaining forests, relatively little is known about the biodiversity in tropical farmland (Daily et al. 2001, Pimentel et al. 1992). Frugivorous birds are an important group of species in tropical farmland ecosystems. Frugivorous birds are significant seed dispersers and can play a prominent role in transporting seeds into disturbed areas and setting the stage for the regeneration of these systems. Isolated fleshy-fruited trees in agricultural landscapes have been shown to attract birds, leading to an increased seed rain and seedling establishment under their canopies (Carrière et al. 2002, Duncan & Chapman 1999, Guevara et al. 1986, 2004; Slocum & Horvitz 2000).

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