Forest cover and landscape heterogeneity shape ant–plant co-occurrence networks in human-dominated tropical rainforests

2018 ◽  
Vol 34 (1) ◽  
pp. 93-104 ◽  
Author(s):  
Erick J. Corro ◽  
Diana A. Ahuatzin ◽  
Armando Aguirre Jaimes ◽  
Mario E. Favila ◽  
Milton Cezar Ribeiro ◽  
...  
Keyword(s):  
Forest Cover ◽  
Landscape Heterogeneity ◽  
Tropical Rainforests

scholarly journals Abandonment of cultural landscapes: butterfly communities track the advance of forest over grasslands

2021 ◽  
Author(s):  
Amparo Mora ◽  
Andrew Wilby ◽  
Rosa Menéndez
Keyword(s):  
Agricultural Intensification ◽  
Forest Cover ◽  
Cultural Landscapes ◽  
Landscape Heterogeneity ◽  
Species Turnover ◽  
Community Response ◽  
Landscape Variables ◽  
Rural Landscapes ◽  
Butterfly Communities

Abstract Rural landscapes in Europe have suffered considerable land-use change in the last 50 years, with agricultural intensification in western regions and land abandonment in eastern and southern regions. The negative impacts of agricultural intensification on butterflies and other insects in western Europe have been well studied. However, less is known about the impacts of abandonment on mountain and humid areas of eastern and southern Europe, where landscapes have remained more natural. We sampled butterfly communities in the Picos de Europa National Park (Spain), a region which is undergoing a process of rural abandonment. 19 hay meadows with different periods of abandonment were studied (long-term 18 years or mid-term abandoned, 3–7 years) and compared to meadows continuously managed in a traditional way. We examined how local meadow characteristics and landscape variables affected butterfly community response to abandonment. Butterfly communities were affected by abandonment, with an overall increase in the density of individuals in the long term. Community composition appears to undergo major change over time, with a species turnover of around 50% in the first few years of abandonment, rising to around 70% after 18 years of abandonment. There was a tendency for species with higher preference for closed habitats to increase their densities as time since abandonment proceeded. Landscape variables had a major impact on butterfly communities, stronger than the effect of meadow management. Community preference for closed habitats was associated with higher forest cover in the surroundings of the meadows, but heterogeneous landscapes (in their composition or configuration) mitigated this effect. Implications for insect conservation Our findings suggest that we should ensure that communities have time to react to the diverse stressors imposed by global change. Facilitating survival to all kinds of functional and taxonomic groups implies promoting landscape heterogeneity and connectivity.

scholarly journals Assessing the Importance of Tree Cover Threshold for Forest Cover Mapping Derived from Global Forest Cover in Myanmar

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1062 ◽  
Author(s):  
Kay Khaing Lwin ◽  
Tetsuji Ota ◽  
Katsuto Shimizu ◽  
Nobuya Mizoue
Keyword(s):  
Large Scale ◽  
Forest Cover ◽  
Remote Sensing Data ◽  
Tree Cover ◽  
Tropical Rainforests ◽  
Forest Change ◽  
Tropical Regions ◽  
Ecological Zones ◽  
Optimal Tree ◽  
Forest Cover Mapping

Comprehensive forest cover mapping is essential for making policy and management decisions. However, creating a forest cover map from raw remote sensing data is a barrier for many users. Here, we investigated the effects of different tree cover thresholds on the accuracy of forest cover maps derived from the Global Forest Change Dataset (GFCD) across different ecological zones in a country-scale evaluation of Myanmar. To understand the effect of different thresholds on map accuracy, nine forest cover maps having thresholds ranging from 10% to 90% were created from the GFCD. The accuracy of the forest cover maps within each ecological zone and at the national scale was assessed. The overall accuracies of ecological zones other than tropical rainforest were highest when the threshold for tree cover was less than 50%. The appropriate threshold for tropical rainforests was 80%. Therefore, different optimal tree cover thresholds were required to achieve the highest overall accuracy depending on ecological zones. However, in the unique case of Myanmar, we were able to determine the threshold across the whole country. We concluded that the threshold for tree cover for creating a forest cover map should be determined according to the areal ratio of ecological zones determined from large-scale monitoring. Our results are applicable to tropical regions having similar ecological zones.

scholarly journals Bee responses to landscape composition on coupled and decoupled multiscale approaches

2021 ◽  
Author(s):  
Lazaro Carneiro ◽  
Milton Cezar Ribeiro ◽  
Willian Moura de Aguiar ◽  
Camila de Fátima Priante ◽  
Wilson Frantine-Silva ◽  
...  
Keyword(s):  
Forest Cover ◽  
Linear Models ◽  
Landscape Heterogeneity ◽  
Spatial Scales ◽  
Landscape Composition ◽  
Landscape Context ◽  
Multiscale Approach ◽  
Ecological Processes ◽  
Positive Effects ◽  
Scale Of Effect

Abstract ContextMultiscale approaches are essential for understanding ecological processes and detecting the scale of effect. However, nested multiscale approaches retain the effect of the landscape attributes from the smaller spatial scales into the larger ones. Thus, decoupling local vs. regional scales can reveal detailed ecological responses to landscape context, but this multiscale approach is poorly explored. ObjectivesWe evaluated the scale of effect of the forest cover (%) and landscape heterogeneity on Euglossini bees combining coupled and decoupled multiscale approaches. MethodsThe Euglossini males were sampled in forest patches from 15 landscapes within the Atlantic Forest, southeast Brazil. For simplicity, we defined that the coupled approaches represented the local scales and decoupled approaches the regional scales. We decoupled the scales by cutting out the smaller scales inserted into larger ones. We estimated the relationship of the bee community attributes with forest cover (%) and landscape heterogeneity in local and regional scales using Generalized Linear Models. ResultsWe found positive effects of landscape heterogeneity on species richness for regional scales. Forest cover and landscape heterogeneity in local scales showed positive effects on the euglossine abundances. The scale of effect for euglossine richness was higher than species abundances. ConclusionsCombining coupled and decoupled multiscale approaches showed adequate capture of the scale of effect of the landscape composition on bee communities. Therefore, it is of paramount importance to measure the influence of the landscape context on biodiversity. Maintaining landscapes with larger forest cover and spatial heterogeneity is essential to keep euglossine species requirements.

Ancient and current resilience in the Chengdu Plain: Agropolitan development re-‘revisited’

Urban Studies ◽  
2019 ◽  
Vol 57 (7) ◽  
pp. 1372-1397 ◽  
Author(s):  
Daniel B Abramson
Keyword(s):  
Forest Cover ◽  
Agricultural Landscape ◽  
Landscape Heterogeneity ◽  
Irrigation System ◽  
Urban Expansion ◽  
Flood Management ◽  
Ecological Resilience ◽  
City Region ◽  
Chengdu Plain ◽  
Landscape Preservation

The Dujiangyan irrigation system, China’s largest, is one of the world’s most important examples of sustainable agropolitan development, maintained by a relatively decentralised system of governance that minimises bureaucratic oversight and depends on significant local autonomy at many scales down to the household. At its historic core in the Chengdu Plain, the system has supported over 2000 years of near-continuously stable urban culture, as well as some of the world’s highest sustained long-term per-hectare productivity and diversity of grain and other crops, especially considering its high population density, forest cover, general biodiversity and flood management success. During the past decade, rapid urban expansion has turned the Chengdu Plain from a net grain exporter into a grain importer, and has radically transformed its productive functioning and distinctive scattered settlement pattern, reorganising much of the landscape into larger, corporately-managed farms, and more concentrated and infrastructure-intensive settlements of non-farming as well as farming households. Community-scale case studies of spatial-morphological and household socio-economic variants on the regional trend help to articulate what is at stake. Neither market-driven ‘laissez-faire’ rural development nor local state-driven spatial settlement consolidation and corporatisation of production seem to correlate well with important factors of resilience: landscape heterogeneity; crop diversity and food production; permaculture; and flexibility in household independence and choice of livelihood. Management of the irrigation system should be linked to community-based agricultural landscape preservation and productive dwelling, as sources of adaptive capacity crucial to the social-ecological resilience of the city-region, the nation and perhaps all humanity.

scholarly journals The Interplay Between Thematic Resolution, Forest Cover, and Heterogeneity for Explaining Euglossini Bees Community in an Agricultural Landscape

2021 ◽  
Vol 9 ◽  
Author(s):  
Lázaro da Silva Carneiro ◽  
Willian Moura de Aguiar ◽  
Camila de Fátima Priante ◽  
Milton Cezar Ribeiro ◽  
Wilson Frantine-Silva ◽  
...  
Keyword(s):  
Landscape Structure ◽  
Forest Cover ◽  
Agricultural Landscape ◽  
Landscape Heterogeneity ◽  
Explanatory Power ◽  
Species Abundance ◽  
Landscape Composition ◽  
Biological Responses ◽  
Thematic Resolution ◽  
Bee Community

Human activities have modified the landscape composition. The changes in the landscape structure can be evaluated by metrics, which are influenced, among other factors, by the number of cover classes used for the landscape classification (thematic resolution). In high thematic resolutions, landscape covers that can influence biological responses are identified and detailed. In low thematic resolutions, this detail level is lower because it aggregates different landscape covers in a few classes. However, how the thematic resolution influences our ability to understand landscape structure on biodiversity is poorly explored, particularly for pollinators. Here we asked how thematic resolution affects the explanatory power of landscape composition on explaining Euglossini bees (richness and abundance) within 15 landscapes composed mainly of coffee and pasture. To address this issue, we quantified the association between five attributes of the euglossine bee community and landscape composition: landscape cover classes (%) and landscape heterogeneity. Moreover, we also evaluated how the thematic resolution influences bee responses to landscape structure. We found a strong and positive influence of landscape heterogeneity in low thematic resolutions (i.e., few cover classes on maps) over the richness and rare species abundance. We also observed that- in addition to the forest cover in the landscape- the pasture cover (%) quantified in high thematic resolution positively influenced the total abundance and abundance of common and intermediate species. Our study highlights the importance of maintaining compositional heterogeneity for the orchid bee community in agroecosystems, and forest cover for the biological requirements and conservation of these pollinators. Moreover, the use of different thematic resolutions showed how specific types of landscape covers influence the euglossine community attributes. This can highlight the species preferences for habitats and landscape covers. Thus, we call the attention of landscape ecologists to the importance of the definition of thematic resolution, as our ability to quantify the association between biological responses and landscape structure may be influenced by the number of classes used when building thematic maps.

The Change of Tangshan Nanhu Wetland Landscape and Ecological Quality Assessment

2011 ◽  
Vol 474-476 ◽  
pp. 200-204
Author(s):  
Ai Hong Guo ◽  
Cheng Jun Wang ◽  
Su Juan Zhang
Keyword(s):  
Environmental Quality ◽  
Forest Cover ◽  
Landscape Heterogeneity ◽  
Land Reclamation ◽  
Analytic Hierarchy ◽  
Construction Land ◽  
Assessment Index ◽  
Landscape Characteristics ◽  
Rs And Gis ◽  
Index Index

Landscape characteristics and dynamics change are studied based on RS and GIS from 1993 to 2007. The results show that there is a big change in Tangshan Nanhu wetland subsidence in the last 15 years. Construction land, water bodies, woodland regional landscape pattern instead of the landscape of construction land and farmland. The change is caused by mining production and land reclamation activities mainly. Take the forest cover index, grass cover index, wetland index, index of landscape heterogeneity, landscape diversity, biological abundance index and Poor index of ecological as assessment index, use analytic hierarchy process to determine the weight of indexes, evaluate Nanhu area eco-environmental quality. The results show that: From 1993 to 2000, there is a slight decline in environmental quality; and since 2000, environmental quality has become better and better.<b></b>

scholarly journals Assessing the impact of different landscape features on post-fire forest recovery with multitemporal remote sensing data: the case of Mount Taygetos (southern Greece)

2019 ◽  
Vol 28 (7) ◽  
pp. 521 ◽  
Author(s):  
Anastasia Christopoulou ◽  
Giorgos Mallinis ◽  
Emmanuel Vassilakis ◽  
Georgios-Pavlos Farangitakis ◽  
Nikolaos M. Fyllas ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Plant Communities ◽  
Forest Cover ◽  
Landscape Heterogeneity ◽  
Remote Sensing Data ◽  
Forest Recovery ◽  
Basement Rock ◽  
Local Conditions ◽  
Landscape Characteristics ◽  
The Impact

Fires affecting large areas usually create a mosaic of recovering plant communities reflecting their pre-fire composition and local conditions of burning. However, post-fire recovery patterns may also reveal the effects of landscape heterogeneity on the natural regeneration process of plant communities. This study combines field data and remote sensing image interpretation techniques to assess the role of various landscape characteristics in the post-fire recovery process in a mountainous region of Greece burned by a severe wildfire. Remote sensing techniques were used to accurately map secluded, large burned areas. By introducing a temporal component, we explored the correlation between post-fire regeneration and underlying topography, soils and basement rock. Pre-fire forest cover was reduced by more than half 8 years after fire. Regarding the dominant pre-fire forest trees, Abies cephalonica did not regenerate well after fire and most pre-fire stands were converted to grasslands and shrublands. In contrast, Pinus nigra regenerated sufficiently to return to its pre-fire cover, especially in areas underlain by softer basement rock. The use of different time series of high-resolution images improved the quality of the results obtained, justifying their use despite their high cost.

scholarly journals Influence of landscape structure on the abundance of Desmodus rotundus (Geoffroy 1810) in northeastern Yucatan, Mexico

2019 ◽  
Vol 6 (17) ◽  
pp. 263
Author(s):  
Beatriz Bolívar-Cimé ◽  
Rafael Flores-Peredo ◽  
Scarlett Aislinn García-Ortíz ◽  
Rene Murrieta-Galindo ◽  
Javier Laborde
Keyword(s):  
Forest Fragmentation ◽  
Forest Cover ◽  
Landscape Heterogeneity ◽  
Negative Impact ◽  
Fragmented Landscape ◽  
Forest Fragments ◽  
Semideciduous Forest ◽  
Desmodus Rotundus ◽  
Landscape Characteristics ◽  
Vampire Bat

Although the transformation of landscapes by human activity can negatively affect the populations of several bat species, other species may benefit from these transformations. One of such species is the vampire bat, Desmodus rotundus, which can often be found in landscapes dominated by livestock activities. Furthermore, there are certain structural landscape characteristics that could be positively influencing the abundance of the vampire bat. To assess this possibility, eight sampling sites in northeastern Yucatan, Mexico were monitored from June 2010 to February 2012. Four sites were located in forest fragments amongst a highly fragmented landscape dominated by pastures dedicated to livestock activities, and four sites were located within continuous tropical semideciduous forest with almost no fragmentation. Forest fragmentation was characterized around the sampling sites within a 2.5 km radius using SPOT images from 2010, and five landscape variables were calculated using FRAGSTATS. The results showed that landscape heterogeneity and an agricultural aggregation index both had a significant effect on the abundance of the vampire bat. Our results showed that D. rotundusabundance in northeastern Yucatan, Mexico was favored by extensive pastures as well as by landscape characteristics associated with intense forest fragmentation. However, the presence of some remnants of forest cover probably enhance the movements and persistence of this species. To reduce the negative impact of the vampire bat presence in these areas dedicated to livestock ranching activities, effective preventive vaccination campaigns could be an important strategy. 

scholarly journals A Satellite-Based Summer Convective Cloud Frequency Analysis over the Southeastern United States

2011 ◽  
Vol 50 (8) ◽  
pp. 1756-1769 ◽  
Author(s):  
Laci D. Gambill ◽  
John R. Mecikalski
Keyword(s):  
United States ◽  
Land Surface ◽  
Forest Cover ◽  
Landscape Heterogeneity ◽  
Southeastern United States ◽  
Vegetation Indices ◽  
Convective Cloud ◽  
Elevation Gradients ◽  
Using Data ◽  
June July

AbstractA convective cloud (CC) analysis is performed over the southeastern United States (SEUS) during June, July, and August 2006 and 2007, using data from the Geostationary Operational Environmental Satellite (GOES) visible and infrared sensors as processed by a satellite-based convection cloud mask and initiation algorithm. Six 5–7-day periods are analyzed between the times 1500 and 1900 UTC, representative of summertime conditions in the SEUS. The ~8.7 × 108 pixel database contains information on nonprecipitating CCs possessing various satellite-estimated attributes of cloud size, based on whether they meet set thresholds in eight infrared “interest fields.” CCs at ~1 km × 1 km pixel size in the GOES projection are evaluated in comparison with the land cover classes, elevation gradients, and normalized difference vegetation indices (NDVIs) beneath the CCs. The goals are to relate the frequency of occurrence of CCs to land surface properties, attempting to determine which of these three properties are most correlated with CCs. CCs are more likely to form over forests and dense vegetation and over higher gradients in elevation. Although forest cover classes are not the most common over the SEUS, CC occurrence increases disproportionately where steeply sloped topography and forests are coincident across large regions of the SEUS. Also, as NDVI increases, the percentage of CCs per land class also increases. Analysis of landscape heterogeneity (combining local variability in land classes, topography, and NDVI) shows that as it increases CC development is more widespread. Thus, lakes among forests and hilly topography intermingled with agricultural lands appear most conducive to high CC frequency.

scholarly journals Spatial patterns and recent trends in the climate of tropical rainforest regions

2004 ◽  
Vol 359 (1443) ◽  
pp. 311-329 ◽  
Author(s):  
Yadvinder Malhi ◽  
James Wright
Keyword(s):  
Forest Cover ◽  
Tropical Rainforest ◽  
Southern Oscillation ◽  
Dry Season ◽  
Tropical Rainforests ◽  
Study Region ◽  
Tropical Asia ◽  
Primary Driver ◽  
Mean Climate ◽  
The Impact

We present an analysis of the mean climate and climatic trends of tropical rainforest regions over the period 1960–1998, with the aid of explicit maps of forest cover and climatological databases. Until the mid–1970s most regions showed little trend in temperature, and the western Amazon experienced a net cooling probably associated with an interdecadal oscillation. Since the mid–1970s, all tropical rainforest regions have experienced a strong warming at a mean rate of 0.26 ± 0.05 °C per decade, in synchrony with a global rise in temperature that has been attributed to the anthropogenic greenhouse effect. Over the study period, precipitation appears to have declined in tropical rainforest regions at a rate of 1.0 ± 0.8% per decade ( p < 5%), declining sharply in northern tropical Africa (at 3–4% per decade), declining marginally in tropical Asia and showing no significant trend in Amazonia. There is no evidence so far of a decline in precipitation in eastern Amazonia, a region thought vulnerable to climate–change–induced drying. The strong drying trend in Africa suggests that this should be a priority study region for understanding the impact of drought on tropical rainforests. We develop and use a dry–season index to study variations in the length and intensity of the dry season. Only African and Indian tropical rainforests appear to have seen a significant increase in dry–season intensity. In terms of interannual variability, the El Niño–Southern Oscillation (ENSO) is the primary driver of temperature variations across the tropics and of precipitation fluctuations for large areas of the Americas and southeast Asia. The relation between ENSO and tropical African precipitation appears less direct.

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