scholarly journals Landscape- and local- level variables affect monarchs in Midwest grasslands

2021 ◽  
Author(s):  
Anna Skye Bruce ◽  
Wayne E. Thogmartin ◽  
Chris Trosen ◽  
Karen Oberhauser ◽  
Claudio Gratton
Keyword(s):  
Habitat Restoration ◽  
Patch Size ◽  
Landscape Heterogeneity ◽  
Local Level ◽  
Forest Edge ◽  
Edge Density ◽  
Patch Quality ◽  
Road Density ◽  
Local Patch ◽  
Migratory Population

Abstract Context It is estimated that over one billion milkweed stems need to be restored to sustain the eastern North American migratory population of monarch butterflies; where and in what context the stems should be placed on the landscape is key to addressing habitat deficits. Objectives We assessed how the amount of appropriate habitat surrounding a particular patch of monarch habitat affects monarch presence and reproduction. To ensure that habitat restoration efforts are targeted towards areas that maximize monarch population growth, it is important to understand the effects of landscape heterogeneity on monarch occurrence in habitat patches (i.e. grasslands with milkweeds) across the landscape. Methods Over two summers (2018-2019), we surveyed monarch adults, larvae, and eggs at sixty grassland sites in Wisconsin that varied in patch size and landscape context (proportion grassland, forest edge density, and road density). We also estimated milkweed density and floral richness to characterize local patch quality. Results Adult monarch abundance was highest at patches with the lowest proportion of surrounding grassland and lowest road density, and was heavily influenced by patch quality variables. Egg and larva density in a patch increased with milkweed density and floral richness within a patch. Patch size was unrelated to monarch abundance. Conclusions These results suggest that optimal sites for monarch habitat restoration are within landscapes with less surrounding habitat and that high milkweed density and floral richness should be conservation goals.

Patch Size and Patch Quality of Gall-inducing Aphids in a Mosaic Landscape in Israel

2005 ◽  
Vol 20 (8) ◽  
pp. 1013-1024 ◽  
Author(s):  
J-J. I. Martinez ◽  
O. Mokady ◽  
D. Wool
Keyword(s):  
Patch Size ◽  
Patch Quality ◽  
Mosaic Landscape

Paddlefish: Ecological, Aquacultural, and Regulatory Challenges of Managing a Global Resource

2019 ◽  
Keyword(s):  
Habitat Restoration ◽  
Local Level ◽  
High Speeds ◽  
The Status ◽  
Low Head ◽  
Management Techniques ◽  
High Head ◽  
Elevated Rate ◽  
Access And Quality

<i>Abstract</i>.—Paddlefish <i>Polyodon spathula</i> are behaviorally, morphologically, and physiologically adapted for prolonged free-swimming at moderately high speeds but not for maneuverability which makes them prone to impacts from submerged structures. These structures include low-head dams, weirs, dikes, levees, high-head dams, dredges, diversions, intakes, and vessels. Impacts include blocked migrations, reduced access and quality of habitat, entrainment, impingement, trauma, and stranding. Effects of these impacts on individuals are displacement, injuries, and death; effects on populations are fragmentation, lower gene flow, lower reproductive success, and elevated rate of mortality. Despite this, the status of the Paddlefish in most parts of its historic range is secure. Management techniques, like stocking and habitat restoration, are typically implemented at the local level but appear effective at conserving the species range wide. Refinement of management techniques, however, is still possible by modifying operations of structures and by rescuing stranded Paddlefish.

Patch Size and Connectivity Thresholds for Butterfly Habitat Restoration

2005 ◽  
Vol 19 (3) ◽  
pp. 887-896 ◽  
Author(s):  
CHERYL B. SCHULTZ ◽  
ELIZABETH E. CRONE
Keyword(s):  
Habitat Restoration ◽  
Patch Size

scholarly journals Comparison of Five Spatio-Temporal Satellite Image Fusion Models over Landscapes with Various Spatial Heterogeneity and Temporal Variation

2019 ◽  
Vol 11 (22) ◽  
pp. 2612 ◽  
Author(s):  
Liu ◽  
Ke ◽  
Yin ◽  
Chen ◽  
Im
Keyword(s):  
Land Cover ◽  
Data Fusion ◽  
Spatial Heterogeneity ◽  
Image Fusion ◽  
Temporal Variation ◽  
Landscape Heterogeneity ◽  
Local Level ◽  
Satellite Image ◽  
Fusion Model ◽  
Large Area

In recent years, many spatial and temporal satellite image fusion (STIF) methods have been developed to solve the problems of trade-off between spatial and temporal resolution of satellite sensors. This study, for the first time, conducted both scene-level and local-level comparison of five state-of-art STIF methods from four categories over landscapes with various spatial heterogeneity and temporal variation. The five STIF methods include the spatial and temporal adaptive reflectance fusion model (STARFM) and Fit-FC model from the weight function-based category, an unmixing-based data fusion (UBDF) method from the unmixing-based category, the one-pair learning method from the learning-based category, and the Flexible Spatiotemporal DAta Fusion (FSDAF) method from hybrid category. The relationship between the performances of the STIF methods and scene-level and local-level landscape heterogeneity index (LHI) and temporal variation index (TVI) were analyzed. Our results showed that (1) the FSDAF model was most robust regardless of variations in LHI and TVI at both scene level and local level, while it was less computationally efficient than the other models except for one-pair learning; (2) Fit-FC had the highest computing efficiency. It was accurate in predicting reflectance but less accurate than FSDAF and one-pair learning in capturing image structures; (3) One-pair learning had advantages in prediction of large-area land cover change with the capability of preserving image structures. However, it was the least computational efficient model; (4) STARFM was good at predicting phenological change, while it was not suitable for applications of land cover type change; (5) UBDF is not recommended for cases with strong temporal changes or abrupt changes. These findings could provide guidelines for users to select appropriate STIF method for their own applications.

Landscape diversity and forest edge density regulate stream water quality in agricultural catchments

2017 ◽  
Vol 72 ◽  
pp. 627-639 ◽  
Author(s):  
Francis Clément ◽  
Julie Ruiz ◽  
Marco A. Rodríguez ◽  
Daniel Blais ◽  
Stéphane Campeau
Keyword(s):  
Water Quality ◽  
Stream Water ◽  
Forest Edge ◽  
Landscape Diversity ◽  
Edge Density ◽  
Stream Water Quality ◽  
Agricultural Catchments

scholarly journals Sensitivity tests for an ensemble Kalman filter for aerosol assimilation

2010 ◽  
Vol 10 (3) ◽  
pp. 5947-5997
Author(s):  
N. A. J. Schutgens ◽  
T. Miyoshi ◽  
T. Takemura ◽  
T. Nakajima
Keyword(s):  
Kalman Filter ◽  
Ensemble Kalman Filter ◽  
Patch Size ◽  
Initial Conditions ◽  
Grid Cell ◽  
Ensemble Size ◽  
Sensitivity Tests ◽  
Local Patch ◽  
The Impact ◽  
Assimilation System

Abstract. We present sensitivity tests for a global aerosol assimilation system utilizing AERONET observations of AOT (aerosol optical thickness) and AAE (aerosol Ångström exponent). The assimilation system employs an ensemble Kalman filter which requires optimization of three numerical parameters: ensemble size nens, local patch size npatch and inflation factor ρ. In addition, experiments are performed to test the impact of various implementations of the system. For instance, we use a different prescription of the emission ensemble or a different combination of observations. The various experiments are compared against one-another and against independent AERONET andMODIS/Aqua observations. The assimilation leads to significant improvements in modelled AOT and AAE fields. Moreover remaining errors are mostly random while they are mostly systematic for an experiment without assimilation. In addition, these results do not depend much on our parameter or design choices. It appears that the value of the local patch size has by far the biggest impact on the assimilation, which has sufficiently converged for an ensemble size of nens=20. Assimilating AOT and AAE is clearly preferential to assimilating AOT at two different wavelengths. In contrast, initial conditions or a description of aerosol beyond two modes (coarse and fine) have only little effect. We also discuss the use of the ensemble spread as an error estimate of the analysed AOT and AAE fields. We show that a very common prescription of the emission ensemble (independent random modification in each grid cell) can have trouble generating sufficient spread in the forecast ensemble.

scholarly journals Medium Plant Cover has the Highest Heterogeneity of Fine-Scale Spatial Vegetation Patterns in Humid grasslands

2021 ◽  
Author(s):  
Qin Yang ◽  
Hua Cheng ◽  
Hongmei Pu ◽  
Xuechun Zhao ◽  
Rui Dong ◽  
...  
Keyword(s):  
Large Scale ◽  
Patch Size ◽  
Management Practices ◽  
Plant Cover ◽  
Rapid Expansion ◽  
Edge Density ◽  
Vegetation Patterns ◽  
Fine Scale ◽  
Ecological Processes ◽  
Patch Density

Abstract Context Fine-scale spatial vegetation patterns are ubiquitous and can have profound impacts on large scale ecological processes including surface runoff, soil erosion, and livestock forage efficiency. However, we have limited knowledge of the fine-scale spatial vegetation patterns in humid grasslands.Objectives The objectives were to characterize the spatial vegetation patterns at centimeter scale in humid grasslands, quantify the vegetation patterns variation under different image pixel sizes and plant covers, and explore the potential ecological implications of the spatial vegetation patterns.Methods Seventy plots with plant covers ranging from 30.8–99.3% were selected from seven humid grasslands in southwest China and their spatial vegetation patterns quantified at image pixel sizes of 0.04, 0.25, 1, and 4 cm.Results With increasing pixel size, plant patch density and total edge density decreased, plant patch size increased, and the plant patch shape became more regular. At a plant cover level below 50%, increasing plant cover will result in increasing patch density and patch size, leading to greater spatial heterogeneity. At plant cover levels above 50%, increasing plant cover will cause the rapid expansion of patch size, along with a lower patch density, forming a more homogeneous landscape dominated by plant patches. The small stems, branches, and leaves of grasses fragmented non-plant patches into smaller patches with increasing plant cover; this fragmentation resembles road-induced landscape fragmentation processes.Conclusions Medium plant cover has the highest heterogeneity of spatial vegetation pattern at the fine scale, which may have significant implications on ecological processes and related management practices.

scholarly journals Forest Edges Negatively Affect Golden-Cheeked Warbler Nest Survival

The Condor ◽  
2007 ◽  
Vol 109 (3) ◽  
pp. 628-637
Author(s):  
Rebecca G. Peak
Keyword(s):  
Breeding Season ◽  
Nest Survival ◽  
Forest Edge ◽  
Breeding Habitat ◽  
Conservation Strategies ◽  
Edge Density ◽  
Parameter Estimates ◽  
Theoretic Approach ◽  
Explanatory Variables ◽  
Information Theoretic Approach

Abstract Abstract. I used an information-theoretic approach to determine support for hypotheses concerning the effects of edge and temporal factors on Golden-cheeked Warbler (Dendroica chrysoparia) nest survival on Fort Hood Military Reservation, Texas, during 2003–2006. I predicted that nest survival would be greater earlier in the breeding season than later in the breeding season, in areas with less forest edge than in areas with more forest edge, and during the laying and incubation stages than during the nestling stage. I used the logistic-exposure method to model nest survival as a function of the explanatory variables and to produce model-based estimates of daily and period survival. The overall daily survival rate was 0.96 (95% CI: 0.94, 0.97) and overall period survival was 0.34 (95% CI: 0.23, 0.46). Forest edge density had the strongest effect on nest survival. Nest survival decreased as forest edge density increased. Period survival tended to decrease as the breeding season progressed, but the 95% confidence intervals of the model-averaged parameter estimates overlapped. These results demonstrate that effective conservation strategies designed to provide high-quality breeding habitat for this endangered species should include measures to reduce predation by edge-adapted predators.

Distribution of arthropods in relation to forest patch size, edge, and stand characteristics

1998 ◽  
Vol 28 (7) ◽  
pp. 1068-1072 ◽  
Author(s):  
Jukka Jokimäki ◽  
Esa Huhta ◽  
Juhani Itämies ◽  
Pekka Rahko
Keyword(s):  
Patch Size ◽  
Forest Edge ◽  
Total Abundance ◽  
Forest Patches ◽  
Forest Patch ◽  
Edge Orientation ◽  
Open Land ◽  
Net Method ◽  
Deciduous Shrubs ◽  
Stand Characteristics

We studied the abundance of arthropods in relation to forest patch size, edge orientation, distance from the forest - open-land edge, and stand characteristics in pine-dominated forests in northern Finland. Arthropod samples were collected using the sweep-net method. The total catch of arthropods, catches from the field layer and deciduous shrubs, the numbers of flying arthropods, small (<1 mm) arthropods, and the numbers of seven different arthropod taxa (viz. Linyphiidae (Arachnida), Cicadellidae (Homoptera), Diptera, Brachycera (Diptera), Nematocera (Diptera), and Hymenoptera and Ichneumonidae (Hymenoptera)) were lower in large forest patches (>5 ha) than in small patches (5 ha). The edge orientation and the type of adjacent open area (clearcut area or treeless mire) had no impact on the abundance of arthopods in the patches. The distance from the forest edge affected the total abundance of arthropods, small arthropods, flying arthropods, and Coleoptera (especially Cantharidae) in that all decreased in number from the forest edge to the interior of the forest stand. The abundance of many arthropod taxa correlated positively with the numbers of saplings, deciduous shrubs, and spruces. It was clear that the existence of these vegetation characteristics mainly explained the observed differences in the abundance of arthropods between forest patches of different sizes and also between forest edges and stand interiors.

Landscape and patch attributes impacting medium- and large-sized terrestrial mammals in a fragmented rain forest

2013 ◽  
Vol 29 (4) ◽  
pp. 331-344 ◽  
Author(s):  
Adriana Garmendia ◽  
Víctor Arroyo-Rodríguez ◽  
Alejandro Estrada ◽  
Eduardo J. Naranjo ◽  
Kathryn E. Stoner
Keyword(s):  
Landscape Metrics ◽  
Rain Forest ◽  
Patch Size ◽  
Forest Cover ◽  
Sampling Site ◽  
Edge Density ◽  
Forest Cover Change ◽  
Terrestrial Mammals ◽  
Number Of Species ◽  
Matrix Quality

Abstract:Understanding the response of biodiversity to land-use changes is an important challenge for ecologists. We assessed the effects of five landscape metrics (forest cover, number of patches, edge density, mean inter-patch isolation distance and matrix quality) and three patch metrics (patch size, shape and isolation) on the number of species and patch occupancy of medium- and large-sized terrestrial mammals in the fragmented Lacandona rain forest, Mexico. We sampled mammal assemblages in 24 forest patches and four control areas within a continuous forest. The landscape metrics were measured within a 100-ha buffer, and within a 500-ha buffer from the centre of each sampling site. A total of 21 species from 13 families was recorded. The number of species increased with shape complexity and patch size at the patch scale, and with matrix quality within 100-ha landscapes. When considering 500-ha landscapes, only the number of patches (i.e. forest fragmentation level) tended to have a negative influence at the community level. Different landscape and patch metrics predicted the occurrence of each species within the sites. Our results indicate that there is a gradient of tolerance to forest cover change, from highly sensitive species to those tolerant of, or even benefited by, forest-cover change.

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