scholarly journals Disentangling effects of local and landscape variables on attractiveness of restored gravel‐sand pits for bat foraging activities

2020 ◽  
Vol 31 (16) ◽  
pp. 2329-2339 ◽  
Author(s):  
Christian Kerbiriou ◽  
Marion Parisot‐Laprun
Keyword(s):  
Landscape Variables ◽  
Sand Pits

scholarly journals Relation between plant species diversity and landscape variables in Central-European dry grassland fragments and their successional derivates

2017 ◽  
Vol 76 (2) ◽  
pp. 111-119
Author(s):  
Igor Paušič ◽  
Danijel Ivajnšič ◽  
Mitja Kaligarič ◽  
Nataša Pipenbaher
Keyword(s):  
Species Diversity ◽  
Plant Species ◽  
Alpha Diversity ◽  
Shape Index ◽  
Plant Species Diversity ◽  
Lower Altitude ◽  
Dry Grassland ◽  
Central European ◽  
Landscape Variables ◽  
Habitat Specialists

AbstractA systematic field survey of an area of 843 ha in the traditional Central-European agricultural landscape of Goričko Nature Park in Slovenia revealed 80 fragments of dry semi-natural grasslands. Vascular plant species diversity was studied in relation to landscape variables and to threat (Slovenian red-listed species). Our results show that fragment size does not affect plant species diversity. In addition, fragment shape index is not related to Alpha diversity. Higher Alpha diversity was observed for abandoned grassland fragments. The lowest Alpha diversity was perceived on more mesic fragments, where habitat specialists are much scarcer. It was confirmed that the highest diversity of specialists are in the driest fragments, both still mowed and abandoned. With an increase in the number of distinctly different bordering habitat types, the total number of species per fragment generally does not increase, except in the case of those fragments that are already in different succession stages. Abandoned and typical dry grasslands are associated with a higher number of bordering habitats. Typical dry grassland fragments and abandoned ones, which probably derived mostly from drier (less productive) grasslands, are found on lower altitude and have a lower shape index. Habitat specialistsSedum sexangulare, Polygala vulgarisandSpiranthes spiralishave higher frequency in fragments with a lower shape index. This means that these oligotrophic specialists occur in smaller fragments. ButOrchis moriohas higher frequencies of occurrence on polygons with a higher shape index, which confirms the observation that this species occurs in larger and more irregular fragments, as well as close to houses and fields and along the roads.

Zooplankton community of sand pits of Paraiba do Sul River basin, São Paulo, Brazil

1998 ◽  
Vol 26 (4) ◽  
pp. 1524-1528
Author(s):  
Maria Aparecida Juliano de Carvalho ◽  
Suzana Sendacz
Keyword(s):  
River Basin ◽  
Zooplankton Community ◽  
Sao Paulo ◽  
São Paulo ◽  
Sand Pits ◽  
Paraíba Do Sul River

scholarly journals Data-driven and interpretable machine-learning modeling to explore the fine-scale environmental determinants of malaria vectors biting rates in rural Burkina Faso

2021 ◽  
Author(s):  
Paul Taconet ◽  
Angélique Porciani ◽  
Dieudonné Diloma Soma ◽  
Karine Mouline ◽  
Frédéric Simard ◽  
...  
Keyword(s):  
Machine Learning ◽  
High Resolution ◽  
Burkina Faso ◽  
Environmental Variables ◽  
Data Driven ◽  
Malaria Vectors ◽  
Environmental Determinants ◽  
Breeding Sites ◽  
Landscape Variables ◽  
Interpretable Machine Learning

AbstractBackgroundImproving the knowledge and understanding of the environmental determinants of malaria vectors abundances at fine spatiotemporal scales is essential to design locally tailored vector control intervention. This work aimed at exploring the environmental tenets of human-biting activity in the main malaria vectors (Anopheles gambiae s.s., Anopheles coluzzii and Anopheles funestus) in the health district of Diébougou, rural Burkina Faso.MethodsAnopheles human-biting activity was monitored in 27 villages during 15 months (in 2017-2018), and environmental variables (meteorological and landscape) were extracted from high resolution satellite imagery. A two-step data-driven modeling study was then carried-out. Correlation coefficients between the biting rates of each vector species and the environmental variables taken at various temporal lags and spatial distances from the biting events were first calculated. Then, multivariate machine-learning models were generated and interpreted to i) pinpoint primary and secondary environmental drivers of variation in the biting rates of each species and ii) identify complex associations between the environmental conditions and the biting rates.ResultsMeteorological and landscape variables were often significantly correlated with the vectors’ biting rates. Many nonlinear associations and thresholds were unveiled by the multivariate models, both for meteorological and landscape variables. From these results, several aspects of the bio-ecology of the main malaria vectors were precised or hypothesized for the Diébougou area, including breeding sites typologies, development and survival rates in relation to weather, flight ranges from breeding sites, dispersal related to landscape openness.ConclusionsUsing high resolution data in an interpretable machine-learning modeling framework proved to be an efficient way to enhance the knowledge of the complex links between the environment and the malaria vectors at a local scale. More broadly, the emerging field of interpretable machine-learning has significant potential to help improving our understanding of the complex processes leading to malaria transmission.

scholarly journals Habitat and Landscape Suitability as Indicators of Bird Abundance in Created and Restored Wetlands

ISRN Ecology ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Jordan W. Mora ◽  
John N. Mager III ◽  
Douglas J. Spieles
Keyword(s):  
Bird Species ◽  
Land Development ◽  
Logistic Models ◽  
Field Measurements ◽  
Road Density ◽  
Bird Abundance ◽  
Aerial Photos ◽  
Landscape Variables ◽  
Buffer Width ◽  
Landscape Scales

We used aerial photography, field measurements, and bird surveys to evaluate 7 Ohio mitigation wetlands for their capacity to support avian guilds at both local and landscape scales. At the local scale, we assessed each wetland with habitat suitability indices (HSI) for eight wetland-dependent bird species as indicators for four guilds: wading, diving, dabbling, and emergent dependent. We characterized landscapes within 2.5 km of each wetland by measuring the buffer width, road density, connectedness, and anthropogenic land development. The changes in landscape variables over time were determined by comparison of aerial photos taken near the time of wetland construction and near the time of this study. Bird abundance data were poorly correlated with HSI scores but were well described with logistic models of buffer width, wetland area, and road density. Our results suggest that landscape variables are better predictors of bird abundance than HSI scores for these guilds in these wetlands.

Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages

2019 ◽  
Keyword(s):  
Land Use ◽  
Fish Assemblage ◽  
Fish Assemblages ◽  
Urban Land ◽  
Urban Land Use ◽  
Stream Fish ◽  
Landscape Variables ◽  
Stream Fish Assemblages ◽  
Anthropogenic Land Use ◽  
Assemblage Metrics

<i>Abstract.</i>—Anthropogenic activities including urbanization, agriculture, and dams degrade stream habitats and are a dominant reason for global biodiversity declines in fluvial fish assemblages. Declining diversity trends have been well documented in many regions of the world; however, fishes vary regionally in response to anthropogenic land use, resulting from complex relationships between landscape variables and mechanisms controlling stream fish assemblages. To test for differences in regional fish response to anthropogenic land use, we conducted our study across five freshwater ecoregions in the temperate mesic portion of the United States and evaluated data characterizing stream fish assemblages from 10,522 locations across all study freshwater ecoregions. Fishes were summarized by metrics describing assemblage structure, trophic groupings of species, levels of tolerance to anthropogenic stressors, and life history characteristics, with seven metrics used for analyses. Natural and anthropogenic landscape variables were assessed across freshwater ecoregions, and we tested for regionally specific influences of percent catchment urbanization, percent catchment agriculture, and catchment densities of dams and stream-road crossings on stream fishes. We used cascade multivariate regression trees to quantify variance explained in fish metrics by these landscape variables after controlling for influences of natural landscape variables, including catchment area, catchment lithology, and elevation of study sites. Results indicated differences in dominant influences by freshwater ecoregion, as well as differences in the levels of anthropogenic land use influencing fishes within and across freshwater ecoregions. For example, urban land use was the most influential anthropogenic land use in both Appalachian Piedmont and Chesapeake Bay freshwater ecoregions, with fish assemblage metrics showing responses at 10% and 1% catchment urban land use, respectively. In contrast, dam density in the network catchment was the most influential anthropogenic variable on fish assemblage metrics in both the Laurentian Great Lakes and Middle Missouri freshwater ecoregions. Also, large amounts of agriculture in the catchment was the most influential anthropogenic land use on fish assemblage metrics in the Upper Mississippi freshwater ecoregion. Knowledge of regional differences in the top contributing anthropogenic landscape variables and the levels at which fish assemblages respond to these variables lends insight into mechanisms controlling stream fish assemblages by freshwater ecoregions and can aid in development of region-specific conservation strategies to prevent biodiversity loss from current and future anthropogenic land use.

Relationships between vegetation and seed bank in sand pits: Effects of different restoration approaches and successional age

2019 ◽  
Vol 22 (2) ◽  
pp. 282-291 ◽  
Author(s):  
Martina Horáčková ◽  
Klára Řehounková ◽  
Karel Prach
Keyword(s):  
Seed Bank ◽  
Sand Pits ◽  
Successional Age

scholarly journals Landscape effects on anuran pond occupancy in an agricultural countryside: barrier-based buffers predict distributions better than circular buffers

2008 ◽  
Vol 86 (7) ◽  
pp. 692-699 ◽  
Author(s):  
Flavio Zanini ◽  
Anna Klingemann ◽  
Rodolphe Schlaepfer ◽  
Benedikt R. Schmidt
Keyword(s):  
Animal Movement ◽  
Methodological Approach ◽  
Landscape Permeability ◽  
Patch Occupancy ◽  
Amphibian Species ◽  
Landscape Variables ◽  
Circular Buffer ◽  
Ecological Barriers ◽  
Land Use Types ◽  
Better Than

Species movement and occupancy of habitat patches are dependent on landscape permeability. Some land-use types (e.g., roads) may be barriers to animal movement. Analyses of the effect of landscape structure on patch occupancy usually use circular buffers around focal patches. The main assumption of this methodological approach is that species are affected by a particular landscape element equally in every direction from a given patch. This assumption is likely not to hold if animal movement is restricted by barriers because barriers reduce movement patterns and reshape the ideal circular buffer into a noncircular buffer. We developed a method to determine the effect of landscape variables on the distribution of two amphibian species that explicitly takes dispersal barriers into account. We extracted landscape variables within (i) circular buffers (CB) and (ii) barrier-based buffers (BBB). BBB were produced by reducing the boundaries of CB according to major impassable barriers. The BBB approach almost doubled the explained deviance of multiple regression models in comparison with the CB approach. Moreover, CB and BBB models included different predictor variables. We suggest that the BBB approach is more useful than the traditional CB analyses of species–habitat relationships because ecological barriers are explicitly taken into account.

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