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1.
Context
Despite decades of research, there is an intense debate about the consistency of the hump-shaped pattern describing the relationship between diversity and disturbance as predicted by the intermediate disturbance hypothesis (IDH). Previous meta-analyses have not explicitly considered interactive effects of disturbance frequency and intensity of disturbance on plant species diversity in terrestrial landscapes.Objective
We conducted meta-analyses to test the applicability of IDH by simultaneously examining the relationship between species richness, disturbance frequency (quantified as time since last disturbance as originally proposed) and intensity of disturbance in forest landscapes.Methods
The effects of disturbance frequency, intensity, and their interaction on species richness was evaluated using a mixed-effects model.Results
We found that species richness peaks at intermediate frequency after both high and intermediate disturbance intensities, but the richness-frequency relationship differed between intensity classes.Conclusions
Our study highlights the need to measure multiple disturbance components that could help reconcile conflicting empirical results on the effect of disturbance on plant species diversity.2.
Alberto Suárez-Esteban Lenore Fahrig Miguel Delibes José M. Fedriani 《Landscape Ecology》2016,31(4):721-729
Context
Seed-dispersing animals often move along “linear gaps” (linear anthropogenic features such as roads and trails that contain little vegetation), especially in densely-vegetated landscapes. As a result, linear gaps and their verges may receive more seeds than adjacent habitats. In addition, linear gap verges may provide more suitable conditions for plant establishment than neighboring habitats. In this way, linear gaps may increase plant abundance and diversity, and facilitate connectivity of native and non-native plant populations, ultimately increasing plant diversity in the landscape.Objectives
We reviewed current evidence for the potential of anthropogenic linear gaps to increase plant abundance and diversity, and for the mechanisms involved.Methods
We reviewed peer-reviewed literature published up to December 31st, 2014.Results
Most (69.2 %) studies found significantly higher plant abundance and/or diversity in linear gap verges than in adjacent habitats. This suggests that linear gaps can increase plant abundance and diversity, and possibly facilitate population spread. However, there was a strong bias toward the study of exotic species. In addition, there were few mechanistic studies to allow estimation of the relative contributions of dispersal and post-dispersal mechanisms operating in linear gaps.Conclusions
Future studies should focus on entire plant communities, not just exotic species, and should allow identification of the mechanisms by which linear gaps increase plant abundance and diversity. With this knowledge in hand, we will be in a better position to understand whether the net benefit of linear gaps for plant diversity in general outweigh their facilitation of the spread of exotic species.3.
Context
The habitat amount hypothesis has rarely been tested on plant communities. It remains unclear how habitat amount affect species richness in habitat fragments compared to island effects such as isolation and patch size.Objectives
How do patch size and spatial distribution compared to habitat amount predict plant species richness and grassland specialist plant species in small grassland remnants? How does sampling area affect the prediction of spatial variables on species richness?Methods
We recorded plant species density and richness on 131 midfield islets (small remnants of semi-natural grassland) situated in 27 landscapes in Sweden. Further, we tested how habitat amount, compared to focal patch size and distance to nearest neighbor predicted species density and richness of plants and of grassland specialists.Results
A total of 381 plant species were recorded (including 85 grassland specialist species). A combination of patch size and isolation was better in predicting both density and richness of species compared to habitat amount. Almost 45% of species richness and 23% of specialist species were explained by island biogeography parameters compared to 19 and 11% by the amount of habitat. A scaled sampling method increased the explanation level of island biogeography parameters and habitat amount.Conclusions
Habitat amount as a concept is not as good as island biogeography to predict species richness in small habitats. Priority in landscape planning should be on larger patches rather than several small, even if they are close together. We recommend a sampling area scaled to patch size in small habitats.4.
Elsa Aggemyr Alistair G. Auffret Love Jädergård Sara A. O. Cousins 《Landscape Ecology》2018,33(12):2273-2284
Context
Understanding how landscape patterns affect species diversity is of great importance in the fields of biogeography, landscape ecology and conservation planning, but despite the rapid advance in biodiversity analysis, investigations of spatial effects on biodiversity are still largely focused on species richness.Objectives
We wanted to know if and how species richness and species composition are differentially driven by the spatial measures dominating studies in landscape ecology and biogeography. As both measures require the same limited presence/absence information, it is important to choose an appropriate diversity measure, as differing results could have important consequences for interpreting ecological processes.Methods
We recorded plant occurrences on 112 islands in the Baltic archipelago. Species richness and composition were calculated for each island, and the explanatory power of island area and habitat heterogeneity, distance to mainland and structural connectivity at three different landscape sizes were examined.Results
A total of 354 different plant species were recorded. The influence of landscape variables differed depending on which diversity measure was used. Island area and structural connectivity determined plant species richness, while species composition revealed a more complex pattern, being influenced by island area, habitat heterogeneity and structural connectivity.Conclusions
Although both measures require the same basic input data, species composition can reveal more about the ecological processes affecting plant communities in fragmented landscapes than species richness alone. Therefore, we recommend that species community composition should be used as an additional standard measure of diversity for biogeography, landscape ecology and conservation planning.5.
Context
Urban environments create a wide range of habitats that harbour a great diversity of plant species, many of which are of alien origin. For future urban planning and management of the green areas within the city, understanding of the spatial distribution of invasive alien species is of great importance.Objectives
Our main aim was to assess how availability of different ecosystem types within a city area, as well as several parameters describing urban structure interact in determining the cover and identity of invasive alien species.Methods
We studied the distribution of chosen invasive plant species in a mid-sized city in the Czech Republic, central Europe, on a gradient of equal sized cells from the city centre to its outskirts.Results
A great amount of variation was explained by spatial predictors but not shared with any measured variables. The species cover of invasive species decreased with increasing proportion of urban greenery and distance from the city centre, but increased with habitat richness; road margins, ruderal sites, and railway sites were richest in invasive species. In contrast, the total number of invasive species in cells significantly decreased with increasing distance from the city centre, but increased with habitat richness.Conclusions
Our results suggest that different invasive species prefer habitats in the vicinity of the city centre and at its periphery and the spatial structure and habitat quality of the urban landscape needs to be taken into account, in efforts to manage alien plant species invasions in urban environments.6.
Balázs Deák Orsolya Valkó Péter Török András Kelemen Ádám Bede András István Csathó Béla Tóthmérész 《Landscape Ecology》2018,33(7):1117-1132
Context
Landscape and habitat filters are major drivers of biodiversity of small habitat islands by influencing dispersal and extinction events in plant metapopulations.Objectives
We assessed the effects of landscape and habitat filters on the species richness, abundance and trait composition of grassland specialist and generalist plants in small habitat islands. We studied traits related to functional spatial connectivity (dispersal ability by wind and animals) and temporal connectivity (clonality and seed bank persistence) using model selection.Methods
We sampled herbaceous plants, landscape (local and regional isolation) and habitat filters (inclination, woody encroachment and disturbance) in 82 grassland islands in Hungary.Results
Isolation decreased the abundance of good disperser specialist plants due to the lack of directional vectors transferring seeds between suitable habitat patches. Clonality was an effective strategy, but persistent seed bank did not support the survival of specialist plants in isolated habitats. Generalist plants were unaffected by landscape filters due to their wide habitat breadth and high propagule availability. Clonal specialist plants could cope with increasing woody encroachment due to their high resistance against environmental changes; however, they could not cope with intensive disturbance. Steep slopes providing environmental heterogeneity had an overall positive effect on species richness.Conclusions
Specialist plants were influenced by the interplay of landscape filters influencing their abundance and habitat filters affecting species richness. Landscape filtering by isolation influenced the abundance of specialist plants by regulating seed dispersal. Habitat filters sorted species that could establish and persist at a site by influencing microsite availability and quality.7.
Context
We address the issue of adapting landscapes for improved insect biodiversity conservation in a changing climate by assessing the importance of additive (main) and synergistic (interaction) effects of land cover and land use with climate.Objectives
We test the hypotheses that ant richness (species and genus), abundance and diversity would vary according to land cover and land use intensity but that these effects would vary according to climate.Methods
We used a 1000 m elevation gradient in eastern Australia (as a proxy for a climate gradient) and sampled ant biodiversity along this gradient from sites with variable land cover and land use.Results
Main effects revealed: higher ant richness (species and genus) and diversity with greater native woody plant canopy cover; and lower species richness with higher cultivation and grazing intensity, bare ground and exotic plant groundcover. Interaction effects revealed: both the positive effects of native plant canopy cover on ant species richness and abundance, and the negative effects of exotic plant groundcover on species richness were greatest at sites with warmer and drier climates.Conclusions
Impacts of climate change on insect biodiversity may be mitigated to some degree through landscape adaptation by increasing woody native vegetation cover and by reducing land use intensity, the cover of exotic vegetation and of bare ground. Evidence of synergistic effects suggests that landscape adaptation may be most effective in areas which are currently warmer and drier, or are projected to become so as a result of climate change.8.
Romaike S. Middendorp Alvaro J. Pérez Armando Molina Eric F. Lambin 《Landscape Ecology》2016,31(7):1581-1599
Context
Natural regenerating forests are rapidly expanding in the tropics. Forest transitions have the potential to restore biodiversity. Spatial targeting of land use policies could improve the biodiversity benefits of reforesting landscapes.Objective
We explored the relative importance of landscape attributes in influencing the potential of tree cover increase to restore native woody plant biodiversity at the landscape scale.Methods
We developed land use scenarios that differed in spatial patterns of reforestation, using the Pangor watershed in the Ecuadorian Andes as a case study. We distinguished between reforestation through natural regeneration of woody vegetation in abandoned fallows and planted forests through managed plantations of exotic species on previously cultivated land. We simulated the restoration of woody plant biodiversity for each scenario using LANDIS-II, a process-based model of forest dynamics. A pair-case comparison of simulated woody plant biodiversity for each scenario was conducted against a random scenario.Results
Species richness in natural regenerating fallows was considerably higher when occurring in: (i) close proximity to remnant forests; (ii) areas with a high percentage of surrounding forest cover; and (iii) compositional heterogeneous landscapes. Reforestation at intermediate altitudes also positively affected restoration of woody plant species. Planted exotic pine forests negatively affected species restoration.Conclusions
Our research contributes to a better understanding of the recolonization processes of regenerating forests. We provide guidelines for reforestation policies that aim to conserve and restore woody plant biodiversity by accounting for landscape attributes.9.
Context
Habitat destruction is the leading threat to terrestrial biodiversity, isolating remnant habitat in a matrix of modified vegetation.Objectives
Our goal was to determine how species richness in several broad taxonomic groups from remnant forest was influenced by matrix quality, which we characterized by comparing plant biomass in forest and the surrounding matrix.Methods
We coupled data on species-area relationships (SARs) in forest remnants from 45 previously published studies with an index of matrix quality calculated using new estimates of plant biomass derived from satellite imagery.Results
The effect size of SARs was greatest in landscapes with low matrix quality and little forest cover. SARs were generally stronger for volant than for non-volant species. For the terrestrial taxa included in our analysis, matrix quality decreased as the proportion of water, ice, or urbanization in a landscape increased.Conclusions
We clearly demonstrate that matrix quality plays a major role in determining patterns of species richness in remnant forest. A key implication of our work is that activities that increase matrix quality, such as active and passive habitat restoration, may be important conservation measure for maintaining and restoring biodiversity in modified landscapes.10.
Helena Tukiainen Janne Alahuhta Richard Field Terhi Ala-Hulkko Raino Lampinen Jan Hjort 《Landscape Ecology》2017,32(5):1049-1063
Context
‘Conserving Nature’s stage’ has been advanced as an important conservation principle because of known links between biodiversity and abiotic environmental diversity, especially in sensitive high-latitude environments and at the landscape scale. However these links have not been examined across gradients of human impact on the landscape.Objectives
To (1) analyze the relationships between land-use intensity and both landscape-scale biodiversity and geodiversity, and (2) assess the contributions of geodiversity, climate and spatial variables to explaining vascular plant species richness in landscapes of low, moderate and high human impact.Methods
We used generalized additive models (GAMs) to analyze relationships between land-use intensity and both geodiversity (geological, geomorphological and hydrological richness) and plant species richness in 6191 1-km2 grid squares across Finland. We used linear regression-based variation partitioning (VP) to assess contributions of climate, geodiversity and spatial variable groups to accounting for spatial variation in species richness.Results
In GAMs, geodiversity correlated negatively, and plant species richness positively, with land-use intensity. Both relationships were non-linear. In VP, geodiversity best accounted for species richness in areas of moderate to high human impact. These overall contributions were mainly due to variation explained jointly with climate, which dominated the models. Independent geodiversity contributions were highest in pristine environments, but low throughout.Conclusions
Human action increases biodiversity but may reduce geodiversity, at landscape scale in high-latitude environments. Better understanding of the connections between biodiversity and abiotic environment along changing land-use gradients is essential in developing sustainable measures to conserve biodiversity under global change.11.
Background
It is well known that preparation of biological (plant and animal) tissues for Scanning Electron Microscopy (SEM) by chemical fixation and critical point drying results in shrinkage of tissues, often by up to 20-30%, depending on the tissue type and fixation protocol used. We sought to identify a protocol that would preserve tissue size and morphology better than standard chemical fixatives and dehydration regimes. We compared a range of processing techniques by quantifying changes in tissue size and recording details of surface morphology using leaf tissues from three commonly studied species; Arabidopsis thaliana, barley and cotton.Results
All processing protocols altered tissue dimensions. Methanol fixation and dehydration, followed by a further short (1 h) dehydration step in ethanol and critical point drying (which was based on a previously published method), preserved tissue dimensions most consistently of all protocols tested, although it did cause 8% shrinkage in all three species. This protocol was also best for preservation of surface morphology in all three species. We outline a recommended protocol and advise that the method is best trialled for different tissues, especially thicker or larger samples.Conclusions
This study shows that simultaneous fixation and dehydration in methanol followed by ethanol results in better preservation of dimensions and morphology of critical point dried plant tissues than other fixation and dehydration procedures. It is a quick and simple method, and requires standard SEM preparation equipment.12.
Context
As global landscapes continue to change, the sustainability of the ecosystem services they support are increasingly coming into question. In the rapidly changing neotropics, multiple-use plants epitomize sources of ecosystem services. To sustain the relationship that exists between such plants and human populations, a sound understanding of their well-being is required.Objectives
Density data on multiple-use plants were compared across forest types and land tenure classes to understand the implications of these two spatial frames of reference for landscape sustainability.Methods
The density of an aggregate sample of seventeen multiple-use and a sub-sample of five species were examined relative to forest type and land tenure class across fourteen Rupununi, Southern Guyana, study sites. The examination of plant density based on the two sample sizes was used to make inferences on how the two frames of reference may impact landscape sustainability.Results
The mean density of the aggregate sample was highest in three of six forest types, but showed no statistical difference across land tenure classes. When individual species were considered mean densities showed no statistical difference across land tenure classes, but differences were observed for three species across forest types. Mean densities were highest in forest types within which swidden agriculture occurs and in the protected area where logging is prohibited.Conclusions
Our findings suggested that in changing tropical landscapes plant species distribution can be predicted by forest types, but land tenure classes may provide clearer signals as to where a species well-being and hence ecosystem services may be compromised.13.
14.
Petra Janečková Štěpán Janeček Jitka Klimešová Lars Götzenberger Jan Horník Jan Lepš Francesco de Bello 《Landscape Ecology》2017,32(4):791-805
Context
Landscape fragmentation significantly affects species distributions by decreasing the number and connectivity of suitable patches. While researchers have hypothesized that species functional traits could help in predicting species distribution in a landscape, predictions should depend on the type of patches available and on the ability of species to disperse and grow there.Objectives
To explore whether different traits can explain the frequency of grassland species (number of occupied patches) and/or their occupancy (ratio of occupied to suitable patches) across a variety of patch types within a fragmented landscape.Methods
We sampled species distributions over 1300 grassland patches in a fragmented landscape of 385 km2 in the Czech Republic. Relationships between functional traits and species frequency and occupancy were tested across all patches in the landscape, as well as within patches that shared similar management, wetness, and isolation.Results
Although some traits predicting species frequency also predicted occupancy, others were markedly different, with competition- and dispersal-related traits becoming more important for occupancy. Which traits were important differed for frequency and occupancy and also differed depending on patch management, wetness, and isolation.Conclusions
Plant traits can provide insight into plant distribution in fragmented landscapes and can reveal specific abiotic, biotic, and dispersal processes affecting species occurrence in a patch type. However, the importance of individual traits depends on the type of suitable patches available within the landscape.15.
Context
Protected areas are a cornerstone of the global strategy for conserving biodiversity, and yet their efficacy in comparison to unprotected areas is rarely tested. In the highly fragmented forests of temperate regions, landscape context and forest history may be more important than protection status for plant species diversity.Objectives
To determine whether there are differences in plant diversity between protected areas and private lands while controlling for landscape context, forest age, and other important factors.Methods
We used a database of 156 one-hectare forest plots distributed over 120,000 km2 in the fragmented forests of southern Ontario to test whether protected areas and private forests differed in native species richness, relative abundance of exotic species, and the probability of finding species of conservation concern.Results
Plots with more forest on the surrounding landscape had higher native species richness, lower abundance of exotic species, and greater probability of supporting at least one species of conservation concern. Young forests tended to have higher abundance of exotics, and were less likely to support species of conservation concern. Surprisingly, privately owned forests had greater native species richness and were more likely to support species of conservation concern once these other factors were accounted for. In addition, there were significant interactions between ownership type, forest history, and landscape context.Conclusions
Our results highlight the importance of privately owned forests in this region, and the need to consider forest history and landscape context when comparing the efficacy of protected areas versus private land for sustaining biodiversity.16.
Context
The relative importance of habitat area and connectivity for species richness is often unknown. Connectivity effects may be confounded with area effects or they may be of minor importance as posited by the habitat-amount hypothesis.Objectives
We studied effects of habitat area and connectivity of linear landscape elements for plant species richness at plot level. We hypothesized that connectivity of linear landscape elements, assessed by resistance distance, has a positive effect on species richness beyond the effect of area and, further, that the relative importance of connectivity varies among groups of species with different habitat preferences and dispersal syndromes.Methods
We surveyed plant species richness in 50 plots (25 m2) located on open linear landscape elements (field margins, ditches) in eight study areas of 1 km2 in agricultural landscapes of Northwest Germany. We calculated the area of linear landscape elements and assessed their connectivity using resistance distance within circular buffers (500 m) around the plots. Effects of area and connectivity on species richness were modelled with generalised linear mixed models.Results
Species richness did not increase with area. Resistance distance had significant negative effects on total richness and on the richness of typical species of grasslands and wetlands. Regarding dispersal syndromes, resistance distance had negative effects on the richness of species with short-distance, long-distance and aquatic dispersal. The significant effects of resistance distance indicated that species richness increased with connectivity of the network of linear landscape elements.Conclusions
Connectivity is more important for plant species richness in linear landscape elements than area. In particular, the richness of plant species that are dispersal limited and confined to semi-natural habitats benefits from connective networks of linear landscape elements in agricultural landscapes.17.
Kaisa J. Raatikainen Anna Oldén Niina Käyhkö Mikko Mönkkönen Panu Halme 《Landscape Ecology》2018,33(12):2169-2187
Context
Habitat loss is a major threat to biodiversity. It can create temporal lags in decline of species in relation to destruction of habitat coverage. Plant species specialized in semi-natural grasslands, especially meadows, often express such extinction debt.Objectives
We studied habitat loss and fragmentation of meadows and examined whether the changes in meadow coverage had caused an extinction debt on vascular plants. We also studied whether historical or present landscape patterns or contemporary environmental factors were more important determinants of species occurrence.Methods
We surveyed the plant species assemblages of 12 grazed and 12 mown meadows in Central Finland and detected the meadow coverages from their surroundings on two spatial scales and on three time steps. We modelled the effects of functional connectivity, habitat amount, and isolation on species richness and community composition.Results
We observed drastic and dynamic meadow loss in landscapes surrounding our study sites during the last 150 years. However, we did not find explicit evidence for an extinction debt in meadow plants. The observed species richness correlated with contemporary factors, whereas both contemporary factors and habitat availability during the 1960s affected community composition.Conclusions
Effective conservation management of meadow biodiversity builds on accurate understanding of the relative importance of past and present factors on species assemblages. Both mown and grazed meadows with high species richness need to be managed in the future. The management effort should preferably be targeted to sites located near to each other.18.
Context
Environmental processes and dispersal are primary determinants of metacommunity dynamics. The relative importance of these effects may vary between species of different abundance classes, given variation in life history traits. Under high disturbance conditions, rare species may be more easily eliminated from their optimal habitats and their distribution may therefore be more heavily dependent upon dispersal from nearby habitat patches than common species.Objectives
We tested if metacommunity dynamics vary between abundance classes in a high disturbance environment.Methods
Standardized butterfly sampling was conducted in the urban parks of Hong Kong. To estimate the strength of environmental processes, we measured an array of environmental variables for all sampled parks. Spatial predictors were generated to estimate the effect of dispersal.Results
For shaping common species compositions, we found environmental processes (and specifically environmental variables including floral density and surrounding woody plant cover) slightly more important than spatial processes. For rare species, only spatial processes were significant while environmental processes were insignificant. Our result contrasts previous studies in natural metacommunities, which have shown that both common and rare species compositions are shaped by environmental processes and similar variables.Conclusions
Our results demonstrate that high disturbance conditions may inhibit rare species establishment and persistence in urban landscapes. Local habitat management may not be sufficient in conserving rare species in urban environments—spatial context and configuration should be considered in planning for biodiversity. We also highlight the utility of community deconstruction analysis in providing insights into rare species metacommunity dynamics.19.