Influence of habitat quality, patch size and connectivity on colonization and extinction dynamics of collared pikas Ochotona collaris

2004 ◽  
Vol 73 (5) ◽  
pp. 889-896 ◽  
Author(s):  
RENEE J. FRANKEN ◽  
DAVID S. HIK
Keyword(s):  
Habitat Quality ◽  
Patch Size ◽  
Ochotona Collaris

scholarly journals Habitat Specificity Modulates the Response of Small Mammals to Habitat Fragmentation, Loss, and Quality in a Neotropical Savanna

2021 ◽  
Vol 9 ◽  
Author(s):  
Ingrid de Mattos ◽  
Bárbara Zimbres ◽  
Jader Marinho-Filho
Keyword(s):  
Species Composition ◽  
Functional Diversity ◽  
Habitat Loss ◽  
Habitat Quality ◽  
Small Mammals ◽  
Small Mammal ◽  
Patch Size ◽  
Landscape Configuration ◽  
Habitat Amount ◽  
Habitat Generalists

Landscape conversion of natural environments into agriculture and pasture are driving a marked biodiversity decline in the tropics. Consequences of fragmentation might depend upon habitat amount in the landscape, while the quality of remnants can also affect some species. These factors have been poorly studied in relation to different spatial scales. Furthermore, the impacts of these human-driven alterations may go beyond species loss, possibly causing a loss of ecosystem function and services. In this study, we investigated how changes in landscape configuration (patch size and isolation), habitat loss (considering a landscape gradient of 10, 25, and 40% of remnant forest cover), and habitat quality (forest structure) affect small mammal abundance, richness, taxonomic/functional diversity, and species composition in fragmented landscapes of semideciduous forests in the Brazilian Cerrado. Analyses were performed separately for habitat generalists and forest specialists. We live-trapped small mammals and measured habitat quality descriptors four times in 36 forest patches over the years 2018 and 2019, encompassing both rainy and dry seasons, with a total capture effort of 45,120 trap-nights. Regression analyses indicated that the effect of landscape configuration was not dependent on the proportion of habitat amount in the landscape to determine small mammal assemblages. However, both patch size and habitat loss impacted different aspects of the assemblages in distinct ways. Smaller patches were mainly linked to an overall increase in small mammal abundance, while the abundance of habitat generalists was also negatively affected by habitat amount. Generalist species richness was determined by the proportion of habitat amount in the landscape. Specialist richness was influenced by patch forest quality only, suggesting that species with more demanding habitat requirements might respond to fragmentation and habitat loss at finer scales. Taxonomic or functional diversity were not influenced by landscape structure or habitat quality. However, patch size and habitat amount in the landscape were the major drivers of change in small mammal species composition in semideciduous forests in the Brazilian savanna.

scholarly journals Colonization of novel algal habitats by juveniles of a marine tube-dwelling amphipod

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10188
Author(s):  
Marilia Bueno ◽  
Glauco B.O. Machado ◽  
Fosca P.P. Leite
Keyword(s):  
Population Dynamics ◽  
Field Experiment ◽  
Habitat Quality ◽  
Patch Size ◽  
Weak Effect ◽  
Important Process ◽  
High Quality ◽  
Dispersal Agent ◽  
Sargassum Filipendula ◽  
Successful Colonization

Background Dispersal is an important process affecting population dynamics and connectivity. For marine direct developers, both adults and juveniles may disperse. Although the distribution of juveniles can be initially constrained by their mothers’ choice, they may be able to leave the parental habitat and colonize other habitats. We investigated the effect of habitat quality, patch size and presence of conspecific adults on the colonization of novel habitats by juveniles of the tube-dwelling amphipod Cymadusa filosa associated with the macroalgal host Sargassum filipendula. Methods We tested the factors listed above on the colonization of juveniles by manipulating natural and artificial plants in both the field and laboratory. Results In the laboratory, juveniles selected high-quality habitats (i.e., natural alga), where both food and shelter are provided, when low-quality resources (i.e., artificial alga) were also available. In contrast, habitat quality and algal patch size did not affect the colonization by juveniles in the field. Finally, the presence of conspecific adults did not affect the colonization of juveniles under laboratory condition but had a weak effect in the field experiment. Our results suggest that C. filosa juveniles can select and colonize novel habitats, and that such process can be partially affected by habitat quality, but not by patch size. Also, the presence of conspecifics may affect the colonization by juveniles. Successful colonization by this specific developmental stage under different scenarios indicates that juveniles may act as a dispersal agent in this species.

scholarly journals Hierarchical habitat-use by an endangered steppe bird in fragmented landscapes is associated with large connected patches and high food availability

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Julia Gómez-Catasús ◽  
Vicente Garza ◽  
Manuel B. Morales ◽  
Juan Traba
Keyword(s):  
Habitat Use ◽  
Food Availability ◽  
Habitat Quality ◽  
Patch Size ◽  
Explanatory Power ◽  
Space Use ◽  
Least Squares Regression ◽  
Fragmented Landscapes ◽  
Hierarchical Nature ◽  
Dupont’S Lark

AbstractMultidimensional approaches must be employed when addressing habitat use patterns. In this study, we aim to elucidate the hierarchical nature of space use by species inhabiting fragmented landscapes, using the threatened Dupont’s lark (Chersophilus duponti). The intensity of space use by Dupont’s lark was estimated using the Kernel Density Function on territory locations in 2015. We measured descriptors of habitat quality at metapopulation (connectivity and patch size), landscape (land-use types and anthropogenic disturbance) and microhabitat-scale (plant structure and composition, herbivore abundance and food availability) at 37 sampling stations. We fitted a Partial Least Squares Regression (PLSR) which yielded two components, accounting for 81% of total variance. Metapopulation-scale factors had the greatest explanatory power (32%), followed by microhabitat (17%) landscape (10%) and spatial predictors (3.6%). Connectivity and patch size were key factors explaining habitat use, and wind farms had a negative effect. At microhabitat-scale, space use was positively associated with Coleoptera, Orthoptera, Araneae and Diptera biomass, but negatively with Formicidae and Blattodea biomass, the cover of Stipa spp, Koeleria vallesiana and moss. This research highlights the hierarchical nature of habitat use in fragmented landscapes. Therefore, conservation measures should ensure connectivity, guarantee a minimum patch size, and improve habitat quality within patches.

Connectivity compensates for low habitat quality and small patch size in the butterfly Cupido minimus

2007 ◽  
Vol 23 (2) ◽  
pp. 259-269 ◽  
Author(s):  
Birgit Binzenhöfer ◽  
Robert Biedermann ◽  
Josef Settele ◽  
Boris Schröder
Keyword(s):  
Habitat Quality ◽  
Patch Size ◽  
Small Patch ◽  
Cupido Minimus

Effects of hypoxia on habitat quality of pelagic planktivorous fishes in the northern Gulf of Mexico

2014 ◽  
Vol 505 ◽  
pp. 209-226 ◽  
Author(s):  
H Zhang ◽  
DM Mason ◽  
CA Stow ◽  
AT Adamack ◽  
SB Brandt ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Habitat Quality ◽  
Northern Gulf Of Mexico

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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