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Kristen A. DaVanon Lindsey K. Howard Karen E. Mabry Robert L. Schooley Brandon T. Bestelmeyer 《Landscape Ecology》2016,31(10):2343-2354
Context
Mechanisms of ecosystem change in urbanizing landscapes are poorly understood, especially in exurban areas featuring residential or commercial development set in a matrix of modified and natural vegetation. We asked how development altered trophic interactions and ecosystem processes in the matrix.Objectives
We examined the effect of varying degrees of exurban development (housing density) on a trophic system that included an apex mammalian predator (coyote, Canis latrans), mammalian herbivores (lagomorphs and rodents), and herbaceous plants. We tested the hypothesis that plant recruitment would be negatively affected by exurban development due either to increases in herbivores associated with increased resource availability (a bottom–up effect) or to a reduction in predators that avoid humans (a top–down effect).Methods
In Las Cruces, New Mexico, USA, four replicate sites were located in each of three urbanization levels: high density exurban, low density exurban, and wildland dominated by Chihuahuan Desert vegetation. Seedling trays measured herbivory rates, live trapping estimated abundance of pocket mice and kangaroo rats, and remotely-triggered wildlife cameras estimated the activity of lagomorphs and coyotes.Results
Increased herbivory on seedlings and decreased herbaceous plant recruitment were observed in high density exurban areas. Overall rodent abundance, seed consumption rates, and activity of the lagomorph Lepus californicus did not vary with urbanization level. Activity by another lagomorph, Sylvilagus audubonii, and coyotes was highest in dense exurban areas, consistent with a bottom–up effect.Conclusions
Exurban development can have important indirect effects on trophic interactions occurring in adjacent, untransformed ecosystems. Similar to earlier studies, such effects in the Chihuahuan Desert may be mediated by bottom–up processes associated with anthropogenic inputs.3.
Pablo M. Vergara Luis O. Meneses Audrey A. Grez Madelaine S. Quiroz Gerardo E. Soto Christian G. Pérez-Hernández Paola A. Diaz Ingo J. Hahn Andrés Fierro 《Landscape Ecology》2017,32(2):279-293
Context
Interactions between landscape-scale processes and fine-grained habitat heterogeneity are usually invoked to explain species occupancy in fragmented landscapes. In variegated landscapes, however, organisms face continuous variation in micro-habitat features, which makes necessary to consider ecologically meaningful estimates of habitat quality at different spatial scales.Objectives
We evaluated the spatial scales at which forest cover and tree quality make the greatest contribution to the occupancy of the long-horned beetle Microplophorus magellanicus (Coleoptera: Cerambycidae) in a variegated forest landscape.Methods
We used averaged data of tree quality (as derived from remote sensing estimates of the decay stage of single trees) and spatially independent pheromone-baited traps to model the occurrence probability as a function of multiple cross-scale combinations between forest cover and tree quality (with scales ranging between 50 and 400 m).Results
Model support and performance increased monotonically with the increasing scale at which tree quality was measured. Forest cover was not significant, and did not exhibit scale-specific effects on the occurrence probability of M. magellanicus. The interactive effect between tree quality and forest cover was stronger than the independent (additive) effects of tree quality and particularly forest cover. Significant interactions included tree quality measured at spatial scales ≥200 m, but cross-scale interactions occurred only in four of the seven best-supported models.Conclusions
M. magellanicus respond to the high-quality trees available in the landscape rather than to the amount of forest per se. Conservation of viable metapopulations of M. magellanicus should consider the quality of trees at spatial scales >200 m.4.
Amy E. Frazier 《Landscape Ecology》2016,31(2):351-363
Context
Considerable research has examined scale effects for patch-based metrics with the ultimate goal of predicting values at finer resolutions (i.e., downscaling), but results have been inconsistent. Surface metrics have been suggested as an alternative to patch-based metrics, although far less is known about their scaling relationships and downscaling potential. If successful, downscaling would enable integration of disparate datasets and comparison of landscapes using different resolution datasets.Objectives
(1) Determine how surface metrics scale as resolution changes and how consistent those scaling relationships are across landscapes. (2) Test whether these scaling relationships can be accurately downscaled to predict metric values for finer resolutions.Methods
Various scaling functions were fit to 16 surface metrics computed for multiple resolutions for a set of landscapes. Best-fitting functions were then extrapolated to test downscaling behavior (i.e., predict metric value for a finer resolution) for an independent set of validation landscapes. Relative error was assessed between the predicted and true values to determine downscaling robustness.Results
Seven surface metrics (Sa, Sq, S10z, Sdq, Sds, Sdr, Srwi) fit consistently well (R2 > 0.99) with a 3rd order polynomial or power law. Of those, the scaling functions for Sa, Sq, and S10z were able to predict metric values at a finer resolution within 5 %. Three metrics, (Ssk, Sku, Sfd) were also notable in terms of fit and downscaling.Conclusions
Many metrics exhibit consistent scaling relations across resolution, and several are able to accurately predict values at finer resolutions. However, prediction accuracy is likely related to the amount of information lost during aggregation.5.
Kimberly A. With 《Landscape Ecology》2016,31(5):969-980
Context
The species–area relationship (SAR) is the most ubiquitous scaling relationship in ecology, yet we still do not know how different aspects of scale affect this relationship. Scale is defined by grain, extent, and focus. Focus here pertains to whether patches or landscapes are used to derive SARs.Objective
To explore whether altering the focal scale influences the resulting SAR. If the SAR is scale-invariant, patch-based and landscape-based SARs should be congruent.Methods
I fit a power-law function (S = cA z) to arthropod data obtained from an experimental landscape system, in which habitat amount and configuration (clumped vs. fragmented) of red clover (Trifolium pratense) varied among plots (256 m2). The scaling coefficient (z) was compared among patch-based and landscape-based SARs for congruence.Results
Patches gained species at a faster rate than landscapes (z = 0.37 vs. 0.26, respectively), producing domains of incongruity in the SAR. Landscape richness (S L) was greater than patch richness (S P) below 30 % habitat, but S P > S L above 60 % habitat. Landscape configuration contributed to this incongruity below 30 % habitat (fragmented S L > clumped S L), but landscape context (whether the largest patch was embedded in a fragmented or clumped landscape) was important above 60 % habitat for understanding the SAR in this domain.Conclusions
Landscape configuration exerts both direct (<30 % habitat) and indirect (>60 % habitat) effects on the SAR. Because patch-based and landscape-based SARs may not be congruent, we should exercise care when extrapolating from patches to landscapes to make inferences about the effects of habitat loss and fragmentation on species richness.6.
Context
Land-use change can reduce and isolate suitable habitat generating spatial variation in resource availability. Improving species distribution models requires a multi-scale understanding of resource requirements and species’ sensitivities to novel landscapes.Objectives
We investigated how the spatial distribution of supplementary habitats (permanent wetlands), urbanization, water depths, and distribution of a key prey species (muskrat; Ondatra zibethicus) influence occupancy dynamics of American mink (Neovison vison). Although mink are widespread across North America and a destructive invasive species in Europe, South America, and Asia, we have a limited understanding of factors affecting their spatial distribution.Methods
We used 6 years of presence–absence data (2007–2012) to evaluate occupancy dynamics of mink at 58–90 stream sites along an urbanization gradient in Illinois, USA. We predicted negative relationships between stream occupancy and urban land cover and distance from permanent wetlands, and positive associations with muskrat presence, water depth, and riparian zone width.Results
Contrary to our hypothesis, stream sites closer to permanent wetlands had lower occupancy and colonization rates for mink. Occupancy and colonization rates were higher at sites with deeper water, and colonization rates were related negatively to urbanization. Mink were more likely to leave stream habitat if muskrats were not present and permanent wetlands were nearby.Conclusion
Factors interplaying across multiple scales influenced occupancy dynamics of mink in stream habitat in a highly modified landscape. Our results highlight the importance of considering both direct measures of prey availability and the spatial distribution of supplementary habitats to improve habitat-selection models for carnivores.7.
Joan Marull Carme Font Enric Tello Nofre Fullana Elena Domene Manel Pons Elena Galán 《Landscape Ecology》2016,31(2):317-336
Context
The role of agricultural landscapes in biodiversity conservation is an emerging topic in a world experiencing a worrying decrease of species richness. Farm systems may either decrease or increase biological diversity, depending on land-use intensities and management.Objectives
We present an intermediate disturbance-complexity model (IDC) of cultural landscapes aimed at assessing how different levels of anthropogenic disturbance on ecosystems affect the capacity to host biodiversity depending on the land matrix heterogeneity. It is applied to the Mallorca Island, amidst the Mediterranean biodiversity hotspot.Methods
The model uses the disturbance exerted when farmers alter the Net Primary Production through land-use change as well as when they remove a share of it (HANPP), together with Shannon–Wiener index (H′) of land-cover diversity. The model is tested with a twofold-scalar experimental design (1:50,000 and 1:5000) of a set of landscape units along three time points (1956, 1989, 2011). Species richness of breeding and wintering birds, taken as a biodiversity proxy, is used in an exploratory factor analysis.Results
The results clearly show that when intermediate levels of HANPP are performed within intermediate levels of complexity (H′) in landscape patterns, like agro-forest mosaics, great bird species richness and high socio-ecological resilience can be maintained. Yet, these complex-heterogeneous landscapes are currently vanishing due to industrial farm intensification, rural abandonment and urban sprawl.Conclusions
The results make apparent the usefulness of transferring the concept of intermediate disturbance-complexity interplay to cultural landscapes. Our spatial-explicit IDC model can be used as a tool for strategic environmental assessment of land-use planning.8.
Michael R. Guttery Christine A. Ribic David W. Sample Andy Paulios Chris Trosen John Dadisman Daniel Schneider Josephine A. Horton 《Landscape Ecology》2017,32(3):515-529
Context
Beyond the recognized importance of protecting large areas of contiguous habitat, conservation efforts for many species are complicated by the fact that patch suitability may also be affected by characteristics of the landscape within which the patch is located. Currently, little is known about the spatial scales at which species respond to different aspects of the landscape surrounding an occupied patch.Objectives
Using grassland bird point count data, we describe an approach to evaluating scale-specific effects of landscape composition on patch occupancy.Methods
We used data from 793 point count surveys conducted in idle and grazed grasslands across Wisconsin, USA from 2012 to 2014 to evaluate scale-dependencies in the response of grassland birds to landscape composition. Patch occupancy models were used to evaluate the relationship between occupancy and landscape composition at scales from 100 to 3000 m.Results
Bobolink (Dolichonyx oryzivorus) exhibited a pattern indicating selection for grassland habitats in the surrounding landscape at all spatial scales while selecting against other habitats. Eastern Meadowlark (Sturnella magna) displayed evidence of scale sensitivity for all habitat types. Grasshopper Sparrow (Ammodramus savannarum) showed a strong positive response to pasture and idle grass at all scales and negatively to cropland at large scales. Unlike other species, patch occupancy by Henslow’s Sparrow (A. henslowii) was primarily influenced by patch area.Conclusions
Our results suggest that both working grasslands (pasture) and idle conservation grasslands can play an important role in grassland bird conservation but also highlight the importance of considering species-specific patch and landscape characteristics for effective conservation.9.
Pierre-Louis Lucas Rodolphe Dumontier Corinne Loutelier-Bourhis Alain Mareck Carlos Afonso Patrice Lerouge Narimane Mati-Baouche Muriel Bardor 《Plant methods》2018,14(1):107
Background
Protein N-glycosylation is initiated within the endoplasmic reticulum through the synthesis of a lipid-linked oligosaccharides (LLO) precursor. This precursor is then transferred en bloc on neo-synthesized proteins through the action of the oligosaccharyltransferase giving birth to glycoproteins. The N-linked glycans bore by the glycoproteins are then processed into oligomannosides prior to the exit of the glycoproteins from the endoplasmic reticulum and its entrance into the Golgi apparatus. In this compartment, the N-linked glycans are further maturated in complex type N-glycans. This process has been well studied in a lot of eukaryotes including higher plants. In contrast, little information regarding the LLO precursor and synthesis of N-linked glycans is available in microalgae.Methods
In this report, a user-friendly extraction method combining microsomal enrichment and solvent extractions followed by purification steps is described. This strategy is aiming to extract LLO precursor from microalgae. Then, the oligosaccharide moiety released from the extracted LLO were analyzed by multistage tandem mass spectrometry in two models of microalgae namely the green microalgae, Chlamydomonas reinhardtii and the diatom, Phaeodactylum tricornutum.Results
The validity of the developed method was confirmed by the analysis of the oligosaccharide structures released from the LLO of two xylosyltransferase mutants of C. reinhardtii confirming that this green microalga synthesizes a linear Glc3Man5GlcNAc2 identical to the one of the wild-type cells. In contrast, the analysis of the oligosaccharide released from the LLO of the diatom P. tricornutum demonstrated for the first time a Glc2Man9GlcNAc2 structure.Conclusion
The method described in this article allows the fast, non-radioactive and reliable multistage tandem mass spectrometry characterization of oligosaccharides released from LLO of microalgae including the ones belonging to the Phaeodactylaceae and Chlorophyceae classes, respectively. The method is fully adaptable for extracting and characterizing the LLO oligosaccharide moiety from microalgae belonging to other phyla.10.
Zachary G. Loman William V. Deluca Daniel J. Harrison Cynthia S. Loftin Brian W. Rolek Petra B. Wood 《Landscape Ecology》2018,33(1):77-91
Context
Species-specific models of landscape capability (LC) can inform landscape conservation design. Landscape capability is “the ability of the landscape to provide the environment […] and the local resources […] needed for survival and reproduction […] in sufficient quantity, quality and accessibility to meet the life history requirements of individuals and local populations.” Landscape capability incorporates species’ life histories, ecologies, and distributions to model habitat for current and future landscapes and climates as a proactive strategy for conservation planning.Objectives
We tested the ability of a set of LC models to explain variation in point occupancy and abundance for seven bird species representative of spruce-fir, mixed conifer-hardwood, and riparian and wooded wetland macrohabitats.Methods
We compiled point count data sets used for biological inventory, species monitoring, and field studies across the northeastern United States to create an independent validation data set. Our validation explicitly accounted for underestimation in validation data using joint distance and time removal sampling.Results
Blackpoll warbler (Setophaga striata), wood thrush (Hylocichla mustelina), and Louisiana (Parkesia motacilla) and northern waterthrush (P. noveboracensis) models were validated as predicting variation in abundance, although this varied from not biologically meaningful (1%) to strongly meaningful (59%). We verified all seven species models [including ovenbird (Seiurus aurocapilla), blackburnian (Setophaga fusca) and cerulean warbler (Setophaga cerulea)], as all were positively related to occupancy data.Conclusions
LC models represent a useful tool for conservation planning owing to their predictive ability over a regional extent. As improved remote-sensed data become available, LC layers are updated, which will improve predictions.11.
Context
Conversion of landscapes is widely associated with loss of biodiversity. While there are several competing hypotheses for the local extinction of species in developed landscapes, experimental approaches are seldom applied to elucidating mechanisms.Objectives
In this study, we focus on the habitat degradation hypothesis and predict that poor quality of relictual wetlands in developed landscapes contributes to the absence of wood frogs (Rana sylvatica = Lithobates sylvaticus) by decreasing their performance.Methods
In a translocation experiment, we reared wood frog larvae within enclosures in seven ponds where they naturally occur and in five ponds in developed landscapes where they are absent. Premature pond drying precluded assessing performance in one present pond and one absent pond.Results
Absent ponds were surrounded by upland buffers dominated by developed land covers while ponds with wood frog breeding populations were surrounded primarily by intact forest. Ponds were largely similar in their attributes. Survival and growth rate did not differ between pond types. Development tended to be slightly more rapid in some absent ponds perhaps related to higher water temperatures.Conclusions
Despite the highly altered landscapes surrounding them, we find no evidence that absent wetlands provide inferior habitat for wood frog larval recruitment. Performance in absent ponds matched or exceeded that observed in present ponds implying that absence of this species may stem from influences mediated by the upland landscape. These results provide a caution to the typically unexamined presumption that relictual habitats in developed landscapes are degraded in their utility for wildlife.12.
Jennifer L. Reidy Frank R. ThompsonIII Courtney Amundson Lisa O’Donnell 《Landscape Ecology》2016,31(2):365-382
Context
Golden-cheeked warblers (Setophaga chrysoparia), an endangered wood-warbler, breed exclusively in woodlands co-dominated by Ashe juniper (Juniperus ashei) in central Texas. Their breeding range is becoming increasingly urbanized and habitat loss and fragmentation are a main threat to the species’ viability.Objectives
We investigated the effects of remotely sensed local habitat and landscape attributes on point occupancy and density of warblers in an urban preserve and produced a spatially explicit density map for the preserve using model-supported relationships.Methods
We conducted 1507 point-count surveys during spring 2011–2014 across Balcones Canyonlands Preserve (BCP) to evaluate warbler habitat associations and predict density of males. We used hierarchical Bayesian models to estimate multiple components of detection probability and evaluate covariate effects on detection probability, point occupancy, and density.Results
Point occupancy was positively related to landscape forest cover and local canopy cover; mean occupancy was 0.83. Density was influenced more by local than landscape factors. Density increased with greater amounts of juniper and mixed forest and decreased with more open edge. There was a weak negative relationship between density and landscape urban land cover.Conclusions
Landscape composition and habitat structure were important determinants of warbler occupancy and density, and the large intact patches of juniper and mixed forest on BCP (>2100 ha) supported a high density of warblers. Increasing urbanization and fragmentation in the surrounding landscape will likely result in lower breeding density due to loss of juniper and mixed forest and increasing urban land cover and edge.13.
Jason J. Kolbe Paul VanMiddlesworth Andrew C. Battles James T. Stroud Bill Buffum Richard T. T. Forman Jonathan B. Losos 《Landscape Ecology》2016,31(8):1795-1813
Context
Urban landscapes are a mixture of built structures, human-altered vegetation, and remnant semi-natural areas. The spatial arrangement of abiotic and biotic conditions resulting from urbanization doubtless influences the establishment and spread of non-native species in a city.Objectives
We investigated the effects of habitat structure, thermal microclimates, and species coexistence on the spread of a non-native lizard (Anolis cristatellus) in the Miami metropolitan area of South Florida (USA).Methods
We used transect surveys to estimate lizard occurrence and abundance on trees and to measure vegetation characteristics, and we assessed forest cover and impervious surface using GIS. We sampled lizard body temperatures, habitat use, and relative abundance at multiple sites.Results
At least one of five Anolis species occupied 79 % of the 1035 trees surveyed in primarily residential areas, and non-native A. cristatellus occupied 25 % of trees. Presence and abundance of A. cristatellus were strongly associated with forest patches, dense vegetation, and high canopy cover, which produced cooler microclimates suitable for this species. Presence of A. cristatellus was negatively associated with the ecologically similar non-native A. sagrei, resulting in reduced abundance and a shift in perch use of A. cristatellus.Conclusions
The limited spread of A. cristatellus in Miami over 35 years is due to the patchy, low-density distribution of wooded habitat, which limits dispersal by diffusion. The presence of congeners may also limit spread. Open habitats—some parks, yards and roadsides—contain few if any A. cristatellus, and colonization of isolated forest habitat appears to depend on human-mediated dispersal.14.
Jean-Pierre Rossi Jacques Garcia Alain Roques Jérôme Rousselet 《Landscape Ecology》2016,31(2):243-254
Context
Various species of forest trees are commonly used for ornamental purposes and are therefore frequently found in nonforest ecosystems. They constitute an important component of the so-called trees outside forests (TOF). Not much is known, however, about the drivers of TOF spatial distribution either in urbanized or in agricultural landscapes since they are generally absent from forest inventories.Objective
The present study focused on the spatial distribution of TOF across agricultural landscapes and their potential role in the dispersal of a forest pest insect, the pine processionary moth, Thaumetopoea pityocampa (PPM).Methods
All the TOF belonging to the genera Pinus, Cedrus and Pseudotsuga were considered as potential hosts and inventoried within a 22 × 22 km study window. We fitted a nonstationary Poisson process to the empirical data and used the distance to the nearest building as a covariate.Results
Both empirical and simulated data indicated that TOF associated to human artifacts/urbanized areas constituted the main source of landscape connectivity for the PPM in the open fields under study. Because they do not account for TOF, forest inventories dramatically underestimate landscape connectivity and provide an erroneous picture of the PPM habitat distribution.Conclusions
We conclude that TOF, especially the ornamental component, must be taken into account when it comes to understanding forest insect landscape dynamics or genetics. The omnipresence of TOF also suggests a potentially huge role in pest dispersal and invasive species expansion.15.
Rachel A. Loehman Robert E. Keane Lisa M. Holsinger Zhiwei Wu 《Landscape Ecology》2017,32(7):1447-1459
Context
Interactions among disturbances, climate, and vegetation influence landscape patterns and ecosystem processes. Climate changes, exotic invasions, beetle outbreaks, altered fire regimes, and human activities may interact to produce landscapes that appear and function beyond historical analogs.Objectives
We used the mechanistic ecosystem-fire process model FireBGCv2 to model interactions of wildland fire, mountain pine beetle (Dendroctonus ponderosae), and white pine blister rust (Cronartium ribicola) under current and future climates, across three diverse study areas.Methods
We assessed changes in tree basal area as a measure of landscape response over a 300-year simulation period for the Crown of the Continent in north-central Montana, East Fork of the Bitterroot River in western Montana, and Yellowstone Central Plateau in western Wyoming, USA.Results
Interacting disturbances reduced overall basal area via increased tree mortality of host species. Wildfire decreased basal area more than beetles or rust, and disturbance interactions modeled under future climate significantly altered landscape basal area as compared with no-disturbance and current climate scenarios. Responses varied among landscapes depending on species composition, sensitivity to fire, and pathogen and beetle suitability and susceptibility.Conclusions
Understanding disturbance interactions is critical for managing landscapes because forest responses to wildfires, pathogens, and beetle attacks may offset or exacerbate climate influences, with consequences for wildlife, carbon, and biodiversity.16.
Riana Gardiner Glen Bain Rowena Hamer Menna E. Jones Christopher N. Johnson 《Landscape Ecology》2018,33(11):1837-1849
Context
The classical theory of island biogeography explains loss of species in fragmented landscapes as an effect of remnant patch size and isolation. Recently this has been challenged by the habitat amount and habitat continuum hypotheses, according to which persistence in modified landscapes is related to total habitat amount rather than habitat configuration or the ability of species to use all habitats to varying degrees. Distinguishing between these theories is essential for effective conservation planning in modified landscapes.Objective
Identify which factors of habitat type, amount and configuration predict the persistence of a keystone woodland specialist, the eastern bettong Bettongia gaimardi, in a fragmented landscape.Method
In the Midlands region of Tasmania we carried out camera surveys at 62 sites in summer and winter. We included habitat and landscape features to model whether habitat amount or patch size and isolation influenced the presence of the eastern bettong, and to measure effects of habitat quality.Results
Habitat amount within a 1 km buffer was a better predictor of occupancy than patch size and isolation. Occupancy was also affected by habitat quality, indicated by density of regenerating stems.Conclusion
Our results support the habitat amount hypothesis as a better predictor of presence. For a species that is able to cross the matrix between remnant patches and utilise multiple patches, the island biogeography concept does not explain habitat use in fragmented landscapes. Our results emphasize the value of small remnant patches for conservation of the eastern bettong, provided those patches are in good condition.17.
Ronan Marrec Gaël Caro Paul Miguet Isabelle Badenhausser Manuel Plantegenest Aude Vialatte Vincent Bretagnolle Bertrand Gauffre 《Landscape Ecology》2017,32(12):2383-2398
Context
Agroecosystems are dynamic, with yearly changing proportions of crops. Explicit consideration of this temporal heterogeneity is required to decipher population and community patterns but remains poorly studied.Objectives
We evaluated the impact on the activity-density of two dominant carabid species (Poecilus cupreus and Anchomenus dorsalis) of (1) local crop, current year landscape composition, and their interaction, and (2) inter-annual changes in landscape composition due to crop rotations.Methods
Carabids were sampled using pitfall-traps in 188 fields of winter cereals and oilseed rape in three agricultural areas of western France contrasting in their spatial heterogeneity. We summarized landscape composition in the current and previous years in a multi-scale perspective, using buffers of increasing size around sampling locations.Results
Both species were more abundant in oilseed rape, and in landscapes with a higher proportion of oilseed rape in the previous year. P. cupreus abundance was negatively influenced by oilseed rape proportion in the current year landscape in winter cereals and positively by winter cereal proportion in oilseed rape. A. dorsalis was globally impacted at finer scales than P. cupreus.Conclusions
Resource concentration and dilution-concentration processes jointly appear to cause transient dynamics of population abundance and distribution among habitat patches. Inter-patch movements across years appear to be key drivers of carabids’ survival and distribution, in response to crop rotation. Therefore, the explicit consideration of the spatiotemporal dynamics of landscape composition can allow future studies to better evidence ecological processes behind observed species patterns and help developing new management strategies.18.
Lia Montti Verónica Piriz Carrillo Jorgelina Gutiérrez-Angonese N. Ignacio Gasparri Roxana Aragón H. Ricardo Grau 《Landscape Ecology》2017,32(11):2167-2185
Context
Knowing which factors determine the spread of plant invaders is a relevant issue in global ecology. Cultural landscapes both influence and are affected by exotic species. Although bioclimatic boundaries, seed sources and landscape configuration all control the invasion process, they have been mostly studied separately and independently from their distant drivers.Objectives
We followed a multiscale approach to describe the invasion dynamics of the Asian tree (Ligustrum lucidum) in subtropical NW Argentina cultural landscapes by: (1) identifying the potential bioclimatic area of invasion, (2) mapping the currently invaded area in peri-urban focal sectors, and (3) quantitatively describing the landscape-scale patterns of invasion in relation to environmental and cultural variables.Method
Niche models were used to map potential invasion area, remote sensing, GIS and field surveys to map patterns of invasion and their association to landscape and environmental variables.Results
Climate suitability to L. lucidum extends over important ranges of the studied area, but currently invaded areas are mostly restricted to clusters around the main cities. The historical and demographic features of cities (e.g., date foundation, population) are important in predicting invaded forest location and spread. At local scale, invasion is associated to abandoned fields nearby urban centers, roads and rivers.Conclusions
The invasion patterns of L. lucidum reflect the combined effect of historical socioeconomic connections between Asia and America, as well as the local cultural landscape history and configuration. Teleconnected cultural landscapes need to be explored as a theoretical framework for the study of biological invasions in the Anthropocene.19.
Hayley R. Tumas Brian M. Shamblin Mark Woodrey Nathan P. Nibbelink Richard Chandler Campbell Nairn 《Landscape Ecology》2018,33(9):1585-1601
Context
Common species important for ecosystem restoration stand to lose as much genetic diversity from anthropogenic habitat fragmentation and climate change as rare species, but are rarely studied. Salt marshes, valuable ecosystems in widespread decline due to human development, are dominated by the foundational plant species black needlerush (Juncus roemerianus Scheele) in the northeastern Gulf of Mexico.Objectives
We assessed genetic patterns in J. roemerianus by measuring genetic and genotypic diversity, and characterizing population structure. We examined population connectivity by delineating possible dispersal corridors, and identified landscape factors influencing population connectivity.Methods
A panel of 19 microsatellite markers was used to genotype 576 samples from ten sites across the northeastern Gulf of Mexico from the Grand Bay National Estuarine Research Reserve (NERR) to the Apalachicola NERR. Genetic distances (FST and Dch) were used in a least cost transect analysis (LCTA) within a hierarchical model selection framework.Results
Genetic and genotypic diversity results were higher than expected based on life history literature, and samples structured into two large, admixed genetic clusters across the study area, indicating sexual reproduction may not be as rare as predicted in this clonal macrophyte. Digitized coastal transects buffered by 500 m may represent possible dispersal corridors, and developed land may significantly impede population connectivity in J. roemerianus.Conclusions
Results have important implications for coastal restoration and management that seek to preserve adaptive potential by sustaining natural levels of genetic diversity and conserving population connectivity. Our methodology could be applied to other common, widespread and understudied species.20.