scholarly journals Regional-scale effects override the influence of fine-scale landscape heterogeneity on rice arthropod communities

2017 ◽  
Vol 246 ◽  
pp. 269-278 ◽  
Author(s):  
Christophe Dominik ◽  
Ralf Seppelt ◽  
Finbarr G. Horgan ◽  
Leonardo Marquez ◽  
Josef Settele ◽  
...  
Keyword(s):  
Landscape Heterogeneity ◽  
Scale Effects ◽  
Regional Scale ◽  
Fine Scale ◽  
Arthropod Communities

scholarly journals Ecological Connectivity in Agricultural Green Infrastructure:  Suggested Criteria for Fine Scale Assessment and Planning

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 807
Author(s):  
Simone Valeri ◽  
Laura Zavattero ◽  
Giulia Capotorti
Keyword(s):  
Land Cover ◽  
Green Infrastructure ◽  
Rural Areas ◽  
Urban Areas ◽  
Landscape Heterogeneity ◽  
Agricultural Landscapes ◽  
Spatial Pattern Analysis ◽  
Fine Scale ◽  
Unique Type

In promoting biodiversity conservation and ecosystem service capacity, landscape connectivity is considered a critical feature to counteract the negative effects of fragmentation. Under a Green Infrastructure (GI) perspective, this is especially true in rural and peri-urban areas where a high degree of connectivity may be associated with the enhancement of agriculture multifunctionality and sustainability. With respect to GI planning and connectivity assessment, the role of dispersal traits of tree species is gaining increasing attention. However, little evidence is available on how to select plant species to be primarily favored, as well as on the role of landscape heterogeneity and habitat quality in driving the dispersal success. The present work is aimed at suggesting a methodological approach for addressing these knowledge gaps, at fine scales and for peri-urban agricultural landscapes, by means of a case study in the Metropolitan City of Rome. The study area was stratified into Environmental Units, each supporting a unique type of Potential Natural Vegetation (PNV), and a multi-step procedure was designed for setting priorities aimed at enhancing connectivity. First, GI components were defined based on the selection of the target species to be supported, on a fine scale land cover mapping and on the assessment of land cover type naturalness. Second, the study area was characterized by a Morphological Spatial Pattern Analysis (MSPA) and connectivity was assessed by Number of Components (NC) and functional connectivity metrics. Third, conservation and restoration measures have been prioritized and statistically validated. Notwithstanding the recognized limits, the approach proved to be functional in the considered context and at the adopted level of detail. Therefore, it could give useful methodological hints for the requalification of transitional urban–rural areas and for the achievement of related sustainable development goals in metropolitan regions.

Impacts of road access on lake trout (Salvelinus namaycush) populations: regional scale effects of overexploitation and the introduction of smallmouth bass (Micropterus dolomieu)

2009 ◽  
Vol 66 (2) ◽  
pp. 212-223 ◽  
Author(s):  
Scott D. Kaufman ◽  
Ed Snucins ◽  
John M. Gunn ◽  
Wayne Selinger
Keyword(s):  
Lake Trout ◽  
Scale Effects ◽  
Regional Scale ◽  
Winter Season ◽  
Salvelinus Namaycush ◽  
Smallmouth Bass ◽  
Micropterus Dolomieu ◽  
Excessive Pressure ◽  
Fishing Activity ◽  
Remote Lakes

In lake trout ( Salvelinus namaycush ) lakes of northeastern Ontario, Canada, aerial surveys of fishing activity on individual lakes (N = 589) and quantitative gillnet surveys (N = 65) were used to assess the effects of road access on angling effort and the presence of introduced smallmouth bass ( Micropterus dolomieu ). Angling effort, particularly during the open-water season, was highest and often exceeded estimated sustainable levels on lakes with good road access. Approximately 25% of the remote lakes also received excessive pressure during the winter season. Angler numerical responses to lake trout abundance were detected in remote lakes, but not in road-accessible lakes. Smallmouth bass were more prevalent in lakes with road access and human settlement (either cottages or lodges), supporting the theory that they were introduced into these lakes. Lake trout populations were depleted throughout much of the study range. Even without road access or smallmouth bass, lake trout abundance was still 47% lower than in unexploited reference lakes. When bass and (or) road access were present, lake trout abundance decreased by 77%. Remote lake trout populations in this area are clearly vulnerable to the negative impacts of improved access, a vector for both overexploitation and species introductions.

Patch-, Landscape-, and Regional-Scale Effects on Biota

2002 ◽  
pp. 58-83 ◽  
Author(s):  
Kathryn Freemark ◽  
Daniel Bert ◽  
Marc-André Villard
Keyword(s):  
Scale Effects ◽  
Regional Scale

scholarly journals Effect of wetland management: Are lentic wetlands refuges of plant-species diversity in the Andean-Orinoco Piedmont of Colombia?

2016 ◽  
Author(s):  
Johanna I. Murillo-Pacheco ◽  
Matthias Rös ◽  
Federico Escobar ◽  
Francisco Castro-Lima ◽  
José R Verdú ◽  
...  
Keyword(s):  
Plant Species ◽  
Plant Diversity ◽  
Landscape Heterogeneity ◽  
Species Turnover ◽  
Wetland Management ◽  
Regional Scale ◽  
Ecological Integrity ◽  
Conservation Strategies ◽  
Fish Farms ◽  
Natural Lakes

Accelerated degradation of the wetlands and fragmentation of surrounding vegetation in the Andean-Orinoco Piedmont are the main threats to diversity and ecological integrity of these ecosystems; however, information on this topic is of limited availability. In this region, we evaluated the value of 37 lentic wetlands as reservoirs of woody and aquatic plants and, analyzed diversity and changes in species composition within and among groups defined according to management given by: 1) type (swamps, heronries, rice fields, semi-natural lakes, constructed lakes and fish farms) and, 2) origins (natural, mixed and artificial). A total of 506 plant species were recorded: 80% woody and 20% aquatic. Of these, 411 species (81%) were considered species typical of the area (Meta Piedmont distribution). Diversity patterns seem to be driven by high landscape heterogeneity and wetland management. The fish farms presented the highest diversity of woody plants, while swamps ranked highest for aquatic plant diversity. Regarding wetland origin, the artificial systems were the most diverse, but natural wetlands presented the highest diversity of typical species and can therefore be considered representative ecosystems at the regional scale. Our results suggest that lentic wetlands act as refuges for native vegetation of Meta Piedmont forest, hosting 55% of the woody of Piedmont species and 29% of the aquatic species of Orinoco basin. The wetlands showed a high species turnover and the results indicated that small wetlands (mean±SD: size = 11±18.7 ha), with a small area of surrounding forest (10±8.6 ha) supported high local and regional plant diversity. To ensure long-term conservation of lentic wetlands, it is necessary to develop management and conservation strategies that take both natural and created wetlands into account.

Sub-grid scale representation of halogen chemistry in volcanic plumes based on 1D MOCAGE model simulations

2021 ◽  
Author(s):  
Virginie Marécal ◽  
Ronan Voisin-Pessis ◽  
Tjarda Roberts ◽  
Paul Hamer ◽  
Alessandro Aiuppa ◽  
...  
Keyword(s):  
Transport Model ◽  
Scale Effects ◽  
Regional Scale ◽  
Global Scale ◽  
Horizontal Resolution ◽  
Mt Etna ◽  
Modelling Studies ◽  
1D Model ◽  
High Concentrations ◽  
The Impact

<p>Halogen halides emitted by volcanoes are known to rapidly convert within plumes into BrO while depleting ozone, as clearly shown by observations and models over the past 2 decades (e.g. review by Gutmann et al., 2018). So far, most of the modelling studies have focused on the plume processes occurring in the first few hours after the emission. The only study at the regional scale is that of Jourdain et al. (2016). They assessed the impact of volcanic halogens for a period of strong degassing of the Ambrym volcano, showing in particular its effect on the atmospheric oxidizing capacity and methane lifetime.</p><p>A step further would be to quantify the impact of volcanic halogens at the global scale using global chemistry models. This type of model uses a horizontal resolution (greater than 50 km) that is much coarser than the plume size. This raises the issue of, whether at this resolution, it is possible to represent the chemistry occurring under high concentrations within the plume. To assess this, a sub-grid scale parameterization is proposed. It has been tested in the 1D version of MOCAGE global and regional chemistry transport model for a short eruption of Mt Etna on the 10<sup>th</sup> of May 2008. The results show that while using the subgrid-scale plume parameterization or not does change the timing of when the maximum BrO occurs but does not affect the predicted maximum concentration. The same finding is made when using a range of different settings in the parameterization regarding dilution of the plume with its environment. The 1D model results show a sensitivity of BrO formation to parameters other than the sub-grid scale effects: composition of the plume at the vent, injection height of the emissions, and time of the day when the eruption takes place.</p>

8. The Effect of Bythotrephes Longimanus on the Size Structure of Zooplankton Communities in the Muskoka Region, Ontario

2017 ◽  
Author(s):  
Johanna Pokorny
Keyword(s):  
Large Scale ◽  
Size Structure ◽  
Scale Effects ◽  
Regional Scale ◽  
Zooplankton Community ◽  
Zooplankton Abundance ◽  
Bythotrephes Longimanus ◽  
Zooplankton Species ◽  
Community Size ◽  
Zooplankton Communities

Invasive species are considered the greatest threat to aquatic ecosystem biodiversity. Bythotrephes longimanus, an exotic zooplankton species introduced to North America in the 1980s, is threatening the structure of indigenous aquatic ecosystems as it continues to invade inland Ontario lakes. As a predacious zooplankton species, B. longimanus has been shown to decrease zooplankton abundance, species richness and shift zooplankton community size structure in invaded lakes. However, much of the previous research concerning the predatory effects of B. longimanus has been on surveys of a small number of lakes or has been in controlled mesocosm or lab-based experiments. This study examines the effects of B. longimanus on the zooplankton community using size-structure characterizations (grouping individuals from the community based on size) as community measures for 311 lakes in the Muskoka Region, a highly invaded watershed in Southern Ontario. More specifically, the study explores the size-spectra of invaded versus uninvaded lakes, with reference to an array of environmental lake characteristics (water chemistry, lake morphometry,etc.), and the relevance of B. longimanus activity on the regional scale. By using such a large-scale survey we will be able to appreciate regional-scale effects, as well as encompass the multiple and more indirect trophic interactions that B. longimanus is likely having with the entire aquatic community. (Funding: NSERC & CAISN.)

A new dendroecological method to differentiate growth responses to fine-scale disturbance from regional-scale environmental variation

2007 ◽  
Vol 37 (6) ◽  
pp. 1034-1043 ◽  
Author(s):  
R. Douglas Thompson ◽  
Lori D. Daniels ◽  
Kathy J. Lewis
Keyword(s):  
Tree Mortality ◽  
Regional Scale ◽  
Ring Width ◽  
Environmental Variation ◽  
Fine Scale ◽  
Growth Responses ◽  
Data Set ◽  
Complementary Approach ◽  
Residual Series ◽  
Species Specific

A new dendroecological method is developed to differentiate growth responses to fine-scale disturbance from regional-scale environmental variation. In spruce–fir forests of central British Columbia, release from suppression in response to overhead canopy tree mortality was calibrated as >60% change in radial growth (%CRG, adjacent 15 year periods compared) using gap-maker–gap-filler pairs with known years of mortality and response. Many release events, attributed to regional-scale environmental variation (e.g., bark beetle outbreaks), were counted. Species-specific regional-scale chronologies were subtracted from standardized gap-filler series producing residuals and 1 was added to all residual indices. Percent divergence (%DIV) values were calculated as the percent change in residuals (adjacent 15 year periods compared). A %DIV criterion was set at >15% increase in the residual series. The %CRG and %DIV criteria were applied to an independent data set of ring-width series, determining the date(s) of release for each tree. %CRG and %DIV criteria were used in a complementary approach to differentiate (i) release due to fine-scale canopy gaps, (ii) no response to a gap and regional-scale environmental variation, (iii) release due to regional-scale environmental variation, and (iv) response to a fine-scale canopy gap but not detected by the %CRG criterion.

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