scholarly journals Getting Lost in the Matrix? On How the Characteristics and Arrangement of Linear Landscape Elements Influence Ecological Connectivity

2021 ◽  
Author(s):  
Calum Anderson ◽  
Justin M. J. Travis ◽  
Stephen C. F. Palmer ◽  
Humphrey Q. P. Crick ◽  
Lesley T. Lancaster
Keyword(s):  
Animal Movement ◽  
Spatial Arrangement ◽  
Suitable Habitat ◽  
Landscape Elements ◽  
Ecological Connectivity ◽  
The Matrix ◽  
Linear Landscape Elements ◽  
Getting Lost ◽  
Agricultural Areas ◽  
Different Characteristics

Abstract ContextLinear landscape elements (LLEs) such as ditches and hedgerows can increase the ecological connectivity of habitat embedded within agricultural areas by acting as corridors for animal movement. However, we lack knowledge on how the spatial arrangement of LLEs influence dispersal, impeding our ability to offer robust advice on how best to add new LLEs to improve connectivity.ObjectivesTo examine how the width and spatial orientations of LLEs composing an intersecting network might influence connectivity across landscapes.MethodsWe used an individual-based dispersal model to simulate the stochastic movement of small organisms through stylised LLEs of different characteristics. Landscapes were composed of two habitat patches separated by a grid-like network of LLEs composed of two types: 1.) connecting-edges (touching patches on either end) and 2.) transecting-edges (running perpendicular to connecting-edges). By altering the numbers and widths of each LLE type we sought to understand the effect of these variables on inter-patch dispersal rates.ResultsIncreasing the number or width of connecting-edges improved connectivity but, conversely, increasing the number or width of transecting-edges reduced it. The greater freedom of movement offered by increasing numbers of transecting-edges may have inhibited connectivity, as individuals with limited perceptual-range were more likely to become trapped in complex networks and thus fail to navigate to suitable habitat patches.ConclusionsThe orientation of LLEs with respect to landscape resources greatly affects their impact on connectivity. The addition of LLEs to landscapes may decrease their connectivity for small, flightless species if they do not directly channel dispersers toward landscape resources.

scholarly journals GIS analysis of change in an agriculture landscape in Central Finland

1996 ◽  
Vol 5 (6) ◽  
pp. 567-576 ◽  
Author(s):  
Riitta Ruuska ◽  
Juha Helenius
Keyword(s):  
Agricultural Landscape ◽  
Average Rate ◽  
Aerial Photographs ◽  
Landscape Elements ◽  
Average Proportion ◽  
Linear Landscape Elements ◽  
Land Survey ◽  
Ecosystem Level ◽  
Agricultural Use ◽  
Index Value

Changes in landscape over a period of 50 years were analysed in a rural area of 324 ha in Central Finland. The data were digitized from aerial photographs of the National Land Survey taken in 1944, 1959, 1979 and 1991, and analysed with the IDRISI™ geographic information system (GIS). The average proportion of land in agricultural use in the sample area was 17.4%. The arable area declined from the maximum of 62.3 ha (1959) to 47.6 ha. The total length of linear landscape elements, predominantly ditch bank habitats, halved, from 876 m/ha of field (1944) to 449 m/ha by the end of the period. The average rate of loss of field boundary habitat was 9.1 m/ha/ year. At the same time, the Shannon-Weaver index of diversity of agricultural landscape elements dropped from 0.37 to 0.24. The number of field parcels declined by 29%, and the mean parcel size increased by 45%, from 1.2 ha to 1.7 ha. The index value of the fractal dimension measuring the complexity of parcel shapes also fell, from 1.88 (1959) to 1.86 (1991). The change in spatial structure reflects the intensification of farming in Finland. Biodiversity at ecosystem level has clearly declined. However, the implications for the agroecosystem and its sustainability are still unknown.

scholarly journals Dispersal across habitat boundaries: uncovering the demographic fates of populations in unsuitable habitat

2021 ◽  
Author(s):  
Megan C. Szojka ◽  
Rachel M. Germain
Keyword(s):  
Temporal Variability ◽  
Adult Life ◽  
Adult Plant ◽  
Suitable Habitat ◽  
Life Stages ◽  
Habitat Types ◽  
The Matrix ◽  
Probabilistic Process ◽  
Habitat Boundaries ◽  
Matrix Patch

AbstractPatchy landscapes are characterized by abrupt transitions among distinct habitat types, forcing species to cross habitat boundaries in order to spread. Since seed dispersal is a probabilistic process, with a kernel that decays with distance, most individuals will fail to reach new, suitable habitat. Although failed dispersers are presumed dead in population models, their demographic fates may not be so simple. If transient survival is possible within unsuitable habitat, then through time, individuals may be able to reach distant, suitable habitat, forming new populations and buffering species from extinction. In a fragmented Californian grassland, we explored the fates of individuals that crossed habitat boundaries, and if those fates differed among specialists dispersing from two habitat types: serpentine habitat patches and the invaded non-serpentine matrix. We surveyed the diversity of seedbank and adult life stages along transects that crossed boundaries between patches and the matrix. First, we considered how patch specialists might transiently survive in the matrix via seed dormancy or stepping-stone populations. Second, we investigated the dispersal of an invasive matrix specialist (Avena fatua) into patches, to assess if sink populations existed across the habitat boundary. We found that dormancy maintained populations of patch specialists deep into the matrix, as abundances of seedbanks and of adult plant communities differed with distance into the matrix. We found evidence that these dormant seeds disperse secondarily with vectors of material flows in the landscape, suggesting that they could eventually reach suitable patches even if they first land in the matrix. We found that A. fatua were largely absent deep in patches, where reproductive outputs plummeted and there was no evidence of a dormant seedbank. Our results not only reveal the demographic fates of individuals that land in unsuitable habitat, but that their ecological consequences differ depending on the direction by which the boundary is crossed (patch → matrix ≠ matrix → patch). Dormancy is often understood as a mechanism for persisting in face of temporal variability, but it may serve as a means of traversing unsuitable habitat in patchy systems, warranting its consideration in estimates of habitat connectivity.

Crystal-Plasticity Simulation of the Evolution of the Matt Surface in Pack Rolling of Aluminium Foil

2014 ◽  
Vol 794-796 ◽  
pp. 553-558 ◽  
Author(s):  
Olaf Engler ◽  
Galyna Laptyeva ◽  
Holger Aretz ◽  
Gernot Nitzsche
Keyword(s):  
Crystal Plasticity ◽  
Large Scale ◽  
Rolling Texture ◽  
Spatial Arrangement ◽  
Alloy Sheet ◽  
Aluminium Foil ◽  
Strain Anisotropy ◽  
Recent Project ◽  
Final Rolling ◽  
Different Characteristics

Aluminium foil is rolled double-layered during the final rolling pass. When the sheets are later separated, the inside surface is dull and the outside surface is shiny. The matt inner side is characterized by significant surface corrugations which are believed to be a precursor for the initiation of fracture upon a subsequent forming operation. Therefore, understanding of the development of the matt side of Al foil will help to control and, eventually, improve the properties of Al foil. It was the goal of the present study to correlate the development of the matt side with the spatial arrangement of the crystallographic orientations of the foil rolling texture. This approach builds on a recent project to correlate the phenomenon of roping in AA 6xxx alloy sheet for car body applications to the occurrence of band-like clusters of grains with similar crystallographic orientation. Large-scale orientation maps obtained by electron back-scattered diffraction (EBSD) were input into a visco-plastic self-consistent crystal-plasticity model to analyse the strain anisotropy caused by the spatial distribution of the various rolling texture components. The new model is applied to several Al foils with different characteristics of the matt side.

Integrating agricultural land-use and management for conservation of a native grassland flora in a variegated landscape

1994 ◽  
Vol 1 (3) ◽  
pp. 236 ◽  
Author(s):  
S. McIntyre
Keyword(s):  
Land Use ◽  
New England ◽  
Agricultural Land ◽  
Planning Process ◽  
Regional Scale ◽  
Spatial Arrangement ◽  
Soil Disturbance ◽  
Land Uses ◽  
The Matrix ◽  
Land Use And Management

Management of variegated landscapes (in which the native vegetation still forms the matrix but has been modified in a variable way) requires strategies to maintain or enhance existing vegetation within the context of human land-uses such as agriculture. Using rangelands in the New England region of New South Wales as an example, spatial patterns of land-use and modification are described. Management principles for conservation of herbaceous communities in areas of pastoral production are suggested, based on the following assumptions: 1) low intensity pasture utilization and management (i.e., limited fertilization, soil disturbance and grazing) is conducive to the maintenance of species richness at a local and regional scale; 2) stratification of management intensity on farms is compatible with viable grazing operations; 3) landscape context is important as effects of management may spread beyond the managed area; 4) spatial arrangement of land-uses could be optimized to maintain or increase diversity. Although our understanding of these issues is incomplete, there is general observational and theoretical support for them. Incorporation of principles derived from these assumptions in the farm planning process is a useful strategy for preserving grassland vegetation in landscapes where opportunities for reserve conservation are limited.

The conservation and ecology of rainforest pigeons in northeastern New South Wales

1995 ◽  
Vol 2 (3) ◽  
pp. 299 ◽  
Author(s):  
E. M. Date ◽  
H. F. Recher ◽  
H. A. Ford ◽  
D. A. Stewart
Keyword(s):  
Native Species ◽  
Food Source ◽  
New South ◽  
New South Wales ◽  
Suitable Habitat ◽  
South Wales ◽  
Winter Food ◽  
Agricultural Areas ◽  
Trees And Shrubs ◽  
Conservation And Management

A survey of conservation reserves, rainforest remnants and agricultural districts in northeastern New South Wales was conducted to determine the abundance, movements and habitat requirements of rainforest pigeons, to evaluate the extent and use of suitable habitat in conservation reserves, and to provide guidelines for the conservation and management of rainforest pigeons. Eight species of rainforest pigeon occur in northeastern New South Wales. Commencing with the clearing of rainforest in the 1860s for agriculture, rainforest pigeons declined in abundance throughout New South Wales and by the 1970s five species were thought to be threatened in the state. Since then, rainforest pigeons have apparently increased in abundance and distribution, but the Wompoo, Rose-crowned and Superb Pigeons continue to be listed by the New South Wales National Parks and Wildlife Service as vulnerable and rare. However, populations of all species of rainforest pigeons in New South Wales are relatively small and vulnerable to further loss of habitat. Most rainforest pigeons show a preference for subtropical rainforest habitat, but moist eucalypt forests, gardens and weedy exotic vegetation along roads and on abandoned farmland are also frequented to varying degrees by different species. To investigate recent trends in pigeon abundance we used data collected for up to 12 years from eight sites and during 1988, 1989 and 1990 from 17 rainforest remnants in northeastern New South Wales. The data suggest that rainforest pigeons now occur more frequently in lowland agricultural areas than in the recent past and tend to confirm an increase in abundance since the 1970s. Nesting and foraging habitats for rainforest pigeons are extensive in the conservation reserve system of northeastern New South Wales, but these habitats, which are largely at high elevations, lack winter food resources. Instead, pigeons congregate in remnant rainforest and exotic berry-bearing trees and shrubs in agricultural areas at lower elevations and near the coast. They rely on these habitats for food during winter and it is the restricted extent of this habitat that probably limits their abundance, not the area or quality of habitat at higher elevations. The conservation and management of rainforest pigeons requires the protection of low elevation and coastal rainforest remnants. As development of northeastern New South Wales proceeds, to avoid a decline in the abundances of rainforest pigeons it will be necessary to protect sclerophyll forest with native or exotic fruit bearing trees and shrubs and to extend the area of suitable habitat by the regeneration of rainforest and by the planting of native species used by pigeons as a food source. This will become increasingly important as the control and removal of exotic plants, such as Lantana Lantana camara and Camphor Laurel Cinnamonum camphora, on which some pigeons depend as a winter food source, becomes more successful.

Regeneration of Quercus spp. along interactive forest boundaries in a fragmented peri-urban landscape of Mexico City

2019 ◽  
Vol 47 (1) ◽  
pp. 39-45
Author(s):  
Yilotl Cázares ◽  
Pablo M Vergara ◽  
Arturo García-Romero
Keyword(s):  
Mexico City ◽  
Urban Landscape ◽  
Canopy Cover ◽  
Tree Height ◽  
Suitable Habitat ◽  
Forest Fragments ◽  
Habitat Conditions ◽  
Edge Distance ◽  
The Matrix ◽  
Zero Inflated Poisson Models

SummaryBiodiversity conservation in forest fragments surrounded by a low-quality matrix requires an understanding of how ecological conditions prevailing in the matrix enter the fragments and interact with local habitat conditions. We assessed the regeneration of oak species along edge–interior gradients in forest fragments at the periphery of Mexico City. The abundance of oak saplings was sampled along transects to the forest, while the edge effect was analysed using segmented zero-inflated Poisson models for abundance data. Three oak species were dominant in terms of their relative abundances: Quercus laeta, Quercus castanea and Quercus obtusata. Regeneration of nine oak species responded nonlinearly to the edge distance, with greater sapling abundance from the edge up to 10 m into the fragment. Canopy cover and tree height decreased from edge to fragment interior, while saplings increased in open areas within the fragments (i.e., independent of edge distance). A posterior analysis indicated that Q. obtusata reacted positively to edges. These results indicate that oak regeneration is promoted by suitable habitat conditions near the boundaries. Therefore, we suggest that forest management should focus on promoting seed production and oak establishment in forest interior habitats.

PLA-Based Biodegradable Copolyester Nanocomposites: Preparation, Characterization and Mechanical Properties

2011 ◽  
Vol 380 ◽  
pp. 290-293
Author(s):  
Bing Tao Wang ◽  
Ping Zhang ◽  
De Gao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Lactic Acid ◽  
Interfacial Adhesion ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Elongation At Break ◽  
Butylene Terephthalate ◽  
The Matrix ◽  
Different Characteristics

In situ melt copolycondensation was proposed to prepare biodegradable copolyester nanocomposites based on degradable components poly(L-lactic acid) (PLA), rigid segments poly(butylene terephthalate) (PBT), and nanoparticles polyhedral oligomeric silsesquioxanes (POSS). The morphologies and dispersions of two POSS nanoparticles (POSS-NH2 and POSS-PEG) in the copolyester PLABT matrix and their effects on the mechanical properties were investigated. The results demonstrated that the morphologies and dispersions of POSS-NH2 and POSS-PEG showed quite different characteristics. POSS-PEG took better dispersion in the PLABT, while POSS-NH2 had poor dispersions and formed crystalline microaggregates. Due to the good dispersion and strong interfacial adhesion of POSS-PEG with the matrix, the tensile strength and Young’s modulus were greatly improved from 6.4 and 9.6 MPa for neat PLABT up to 11.2 and 70.7 MPa for PLABT/POSS-PEG nanocomposite. Moreover, the incorporation of POSS-PEG could impart macromolecular chains good flexibility and improve the mobility of the chains, so the the elongation at break of PLABT/POSS-PEG nanocomposite dramatically increased from 190 to 350 % compared with neat PLABT.

scholarly journals Building walls around open wells prevent Asiatic Lion Panthera leo persica (Mammalia: Carnivora: Felidae) mortality in the Gir Lion Landscape, Gujarat, India

2020 ◽  
Vol 12 (3) ◽  
pp. 15301-15310
Author(s):  
Tithi Kagathara ◽  
Erach Bharucha
Keyword(s):  
Agricultural Landscape ◽  
Low Cost ◽  
High Rate ◽  
Landscape Elements ◽  
Human Interactions ◽  
Asiatic Lion ◽  
Dug Wells ◽  
Peripheral Areas ◽  
Building Walls ◽  
Agricultural Areas

The Asiatic Lion population has increased in the last three decades, which now occupies a large regional spread with six or more identified satellite populations in eight districts of Gujarat.  An overlap of lion habitat with human-dominated landscape elements leads to an increase in lion-human interactions in these growing satellite populations.  A high rate of lion mortality has been observed in the periphery of Gir in the last decade due to falls into open dug wells.  These wells have been excavated for irrigation in the agricultural landscape of Gir.  About 145 wild animals including lions have died due to accidental falls into open wells in past 10 years.  It has been observed that construction of parapet walls around wells in some of the peripheral areas of Gir Sanctuary have prevented this accidental mortality at very low cost.  To assess the efficiency of these measures we did a survey of 20 random villages in the Gir Lion Landscape to collect data on the types of wells that cause this uncalled-for mortality.  The paper explores the reasons for the lions falling into wells in the agricultural areas outside the Gir Sanctuary.  The survey has shown that the corridors used by lions and in the satellite population areas are high risk sites where more parapet walls should be built on a priority basis.  From the year 2007 to 2018 more than 48,000 parapet walls have already been randomly built in the periphery of the Gir Sanctuary.  Out of 130 identified wells, 90 were protected with parapet wall or iron net while, 32 were without parapet wall and rest eight were with unfinished parapet wall.  Providing a scheme for building more parapet walls around prioritized open wells would be an effective step towards Asiatic Lion conservation in the Gir Lion Landscape.  Our survey indicates that there has been no mortality of lions in those wells where parapet walls have been built.

scholarly journals Forest edges and their effects on the arrival of dragonflies at north-temperate experimental ponds

2021 ◽  
Vol 24 ◽  
pp. 38-50
Author(s):  
Laís M. S. N. Leite ◽  
◽  
Sarah K. French ◽  
Christopher A. Searcy ◽  
Shannon J. McCauley
Keyword(s):  
Forest Edge ◽  
Forest Edges ◽  
Species Dispersal ◽  
Landscape Elements ◽  
Habitat Patches ◽  
Close Proximity ◽  
The Matrix ◽  
Terrestrial Environments ◽  
A Site ◽  
Experimental Ponds

The matrix, an environment in the landscape that individuals move through but do not reside in, can affect species dispersal and the arrival of individuals at habitat patches. Elements around this matrix that provide refuge or resources may shape the arrival of animals at habitat patches, even when those patches are equivalent in quality. Adult dragonflies (Odonata: Anisoptera) frequently use open terrestrial environments during movement and dispersal in north-temperate regions; however, they can also roost along forest edges. Because of the potential value of forest edges to adult dragonflies, we tested whether pond proximity (i.e., connectivity) to multiple forest edges was positively related to the abundance or diversity of arriving dragonflies. We observed dragonflies arriving at 9 experimental pond sites located within an open field landscape in Ontario, Canada. Experimental ponds differed in their distance to source ponds and to forest edges, a potential refuge for dragonflies. We found no effect of connectivity to forest edges or distance to source ponds on the abundance or diversity of dragonflies arriving at a site. Dragonfly dispersal was therefore not limited at the spatial scale of our study (<305 m to source ponds). In addition, dragonflies did not seem to discriminate among sites based on the amount of nearby forest edge, although all sites within the generally open landscape had at least some forest edge in close proximity (10–79 m). Our results provide greater insight regarding the decisions that dragonflies make in response to landscape elements while dispersing to reproductive habitats.

scholarly journals Context matters: the landscape matrix determines the population genetic structure of temperate forest herbs across Europe

2021 ◽  
Author(s):  
Tobias Naaf ◽  
Jannis Till Feigs ◽  
Siyu Huang ◽  
Jörg Brunet ◽  
Sara A. O. Cousins ◽  
...  
Keyword(s):  
Gene Flow ◽  
Landscape Structure ◽  
Population Genetic ◽  
Temperate Forest ◽  
Agricultural Landscapes ◽  
Plant Populations ◽  
Landscape Elements ◽  
Forest Herbs ◽  
Species Population ◽  
Linear Landscape Elements

Abstract Context Plant populations in agricultural landscapes are mostly fragmented and their functional connectivity often depends on seed and pollen dispersal by animals. However, little is known about how the interactions of seed and pollen dispersers with the agricultural matrix translate into gene flow among plant populations. Objectives We aimed to identify effects of the landscape structure on the genetic diversity within, and the genetic differentiation among, spatially isolated populations of three temperate forest herbs. We asked, whether different arable crops have different effects, and whether the orientation of linear landscape elements relative to the gene dispersal direction matters. Methods We analysed the species’ population genetic structures in seven agricultural landscapes across temperate Europe using microsatellite markers. These were modelled as a function of landscape composition and configuration, which we quantified in buffer zones around, and in rectangular landscape strips between, plant populations. Results Landscape effects were diverse and often contrasting between species, reflecting their association with different pollen- or seed dispersal vectors. Differentiating crop types rather than lumping them together yielded higher proportions of explained variation. Some linear landscape elements had both a channelling and hampering effect on gene flow, depending on their orientation. Conclusions Landscape structure is a more important determinant of the species’ population genetic structure than habitat loss and fragmentation per se. Landscape planning with the aim to enhance the functional connectivity among spatially isolated plant populations should consider that even species of the same ecological guild might show distinct responses to the landscape structure.

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