scholarly journals Matrix quality determines the strength of habitat loss filtering on bird communities at the landscape scale

2021 ◽  
Author(s):  
Melina de Souza Leite ◽  
Andrea Larissa Boesing ◽  
Jean Paul Metzger ◽  
Paulo Inácio Prado
Keyword(s):  
Habitat Loss ◽  
Community Assembly ◽  
Forest Cover ◽  
Landscape Scale ◽  
Native Forest ◽  
Strong Impact ◽  
High Quality ◽  
Matrix Quality ◽  
The Matrix ◽  
Ecological Drift

Habitat loss and fragmentation represent a major threat to biodiversity, however, the modulation of its effects by the non-habitat matrix surrounding habitat patches is still undervalued. The landscape matrix might change community assembly in different ways. For example, low-quality matrices can accentuate environmental filtering by reducing resource availability and/or deteriorating abiotic conditions but they may also over limit dispersal of organisms and make communities more prone to ecological drift. To understand how matrix quality modulates the effects of habitat loss, we quantified the relative importance of environmental filter and ecological drift in bird occurrences across both local and landscape gradients of habitat loss embedded in low- and high-quality matrices. We used a trait-based approach to understand habitat loss filtering effects on birds. We found that low-quality matrices, composed mainly of low-productive pasturelands, increased the severity of habitat loss filtering effects for forest specialist birds, but only at the landscape scale. Bird occurrence was in general higher in high-quality matrices, i.e., more heterogeneous and with low-contrasting edges, indicating the role of the matrix quality on attenuating species extinction risks at the landscape scale probably due to mass effect. Moreover, forest specialists presented a strong negative response to habitat loss filtering across different functional traits, while generalists presented a high variability in traits response to habitat loss. We raised evidence in supporting that landscape habitat loss filtering may be relaxed or reinforced depending on the quality of the matrix, evidencing that matrix quality has a strong impact in modulating community assembly processes in fragmented landscapes. In practical terms, it means that improving matrix quality may help in maintaining the high diversity of birds even without any increase in native forest cover.

scholarly journals INFLUÊNCIA HIPSOMÉTRICA NA FRAGMENTAÇÃO EM REGIÕES SEMIÁRIDAS

Nativa ◽  
2018 ◽  
Vol 6 ◽  
pp. 824
Author(s):  
Jéssica Stefane Alves Cunha ◽  
Ana Lícia Patriota Feliciano ◽  
Emanuel Araújo Silva ◽  
Luiz Carlos Marangon ◽  
Fabiana Estigarribia
Keyword(s):  
Altitudinal Gradient ◽  
Arid Regions ◽  
Forest Cover ◽  
Native Vegetation ◽  
Native Forest ◽  
Arid Areas ◽  
The Matrix ◽  
Categorical Maps ◽  
Semi Arid ◽  
Do So

A degradação da floresta nativa, em regiões secas, encontra-se em expansão devido a exploração da madeira e à conversão da vegetação em distintos usos. Assim, objetivou-se analisar a fragmentação da paisagem em áreas semiáridas e a influência do gradiente altitudinal nesse processo. Para tanto, as imagens RapidEye adquiridas no ano de 2014 foram segmentadas, identificadas e classificadas em Floresta e Outros usos, bem como confeccionados mapas categóricos para utilizar no software Fragstats e gerar dados para análise das métricas da paisagem. Os resultados dos parâmetros determinaram que as regiões secas possuem uma alta quantidade de fragmentos menores que cinco ha demonstrando um alto retalhamento. O ambiente Baixada é o mais prejudicado, diante da maior quantidade de fragmentos menores e da distância entre os mesmos, isso é devido a cobertura florestal desse ambiente está sob pressão sendo mais vulnerável à fragmentação, em virtude do cultivo agrícola e pastagem. De forma oposta se encontra o ambiente Chapada, no qual a classe Floresta comporta-se como a matriz da paisagem. Portanto, a altitude influencia o processo de fragmentação da vegetação nativa de regiões semiáridas, uma vez que ao aumentar a altitude também aumenta a conectividade entre os fragmentos.Palavras-chave: Análise da paisagem, métricas, Brasil, gradiente, fragstats. HYPSOMETRIC INFLUENCE IN FRAGMENTATION IN SEMI-ARID REGIONS ABSTRACT:The degradation of native forest, in dry regions, is expanding due to the exploitation of wood and the conversion of vegetation to different uses. Thus, the objective was to analyze the fragmentation of the landscape in semi-arid areas and the influence of the altitudinal gradient in this process. To do so, the RapidEye images acquired in the year of 2014 were segmented, identified and classified in Forest and Other uses, and also categorical maps were made to be used in the Fragstats software and generate data for analysis of the landscape metrics. The results of the parameters determined that the dry regions have a high amount of fragments smaller than five, demonstrating a high shredding. The Lowland environment is the most affected, due to the greater amount of smaller fragments and the distance between them, this is due to the forest cover of this environment is under pressure being more vulnerable to fragmentation, due to the agricultural cultivation and pasture. On the opposite side is the Plateau environment, in which the Forest class behaves as the matrix of the landscape. Therefore, altitude influences the fragmentation process of native vegetation of semiarid regions, since increasing the altitude also increases the connectivity between the fragments.Keywords: Landscape analysis, metrics, Brazil, gradient, fragstats.

scholarly journals Mexican agricultural frontier communities differ in forest dynamics with consequences for conservation and restoration

2021 ◽  
Author(s):  
Madelon Lohbeck ◽  
Ben DeVries ◽  
Frans Bongers ◽  
Miguel Martinez-Ramos ◽  
Armando Navarrete-Segueda ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Forest Conservation ◽  
Forest Cover ◽  
Secondary Forest ◽  
Forest Loss ◽  
Secondary Forests ◽  
High Quality ◽  
Agricultural Frontier ◽  
Forest Regrowth ◽  
Land Availability

Forest regrowth is key to achieve restoration commitments, but we need to better understand under what circumstances it takes place and how long secondary forests persist. We studied a recently colonized agricultural frontier in southern Mexico. We quantified the spatiotemporal dynamics of forest loss and regrowth and tested how temporal variation in climate, and spatial variation in land availability, land quality and accessibility affect forest disturbance, regrowth and secondary forest persistence. Marqués de Comillas consistently exhibits more forest loss than regrowth, resulting in a net decrease of 30% forest cover (1991-2016). Secondary forest cover remained relatively constant while secondary forest persistence increased, suggesting that farmers are moving away from shifting cultivation. Temporal variation in disturbance and regrowth were explained by the annual variation in the Oceanic El Niño index combined with dry season rainfall and key policy and market interventions.Across communities the availability of high-quality soil overrules the effects of land availability and accessibility, but that at the pixel-level all three factors contributed to explaining forest conservation and restoration. Communities with more high-quality soils were able to spare land for forest conservation, and had less secondary forest that persisted for longer. Old forest and secondary forests were better represented on low-quality lands and on communal land. Both old and secondary forest were less common close to the main road, where secondary forests were also less persistent. Forest conservation and restoration can be explained by a complex interplay of biophysical and social drivers across time, space and scale. We warrant that stimulating private land ownership may cause remaining forest patches to be lost and that conservation initiatives should benefit the whole community. Forest regrowth and secondary forest persistence competes with agricultural production and ensuring farmers can access restoration benefits is key to success.

scholarly journals Force parameters of metal deformation during sheet drawing

2020 ◽  
Vol 16 (6) ◽  
pp. 493-503
Author(s):  
Yury A. Morozov
Keyword(s):  
Stress State ◽  
Strain State ◽  
Sheet Material ◽  
Forming Force ◽  
High Quality ◽  
State Process ◽  
The Matrix ◽  
Metal Deformation ◽  
Volumetric Stress ◽  
Steady State Process

The aim of the work. The effect of the curvature of the rounding of torus surfaces during the formation of a cylindrical product (glass) is investigated, taking into account the plastic thinning of the deformable material at the end edges of the matrix and pressing punch. Methods. The existing scheme for determining the power parameters of sheet drawing is analyzed, based on the assumption of the implementation of some abstract stress state in the material; mainly conditional tensile strength. At the same time, the possibility of forming the product without destruction determines the obvious overestimation of the stress level. A mathematical model of the volumetric stress state of the metal is being developed, which makes it possible to assess the deformation and stress state during the formation of a cold-drawn product, i. e. the folding of the sheet blank along the end radius of the rounding of the pressing punch and the steady-state process of drawing the blank into the deformation zone with successive bending/straightening of the material along the edge of the matrix are considered. The level of radial stresses during folding and stretching of sheet material is estimated, taking into account its strain hardening and thinning, which determine the forming force. The obtained results will make it possible to simulate the stress-strain state of the metal during the development of sheet drawing technology: to establish the amount of thinning, to estimate the level of radial stresses in the formation of rounding of torus surfaces along the end edges of the matrix and the pressing punch, as well as to determine the power parameters of the formation, which will prevent the destruction of the pulled part, guaranteeing obtaining high-quality products and more accurately choosing the deforming equipment.

scholarly journals Multi-taxa ecological responses to habitat loss and fragmentation in western Amazonia as revealed by RAPELD biodiversity surveys

2021 ◽  
Vol 51 (3) ◽  
pp. 234-243
Author(s):  
Gabriel M. MOULATLET ◽  
Emmanuel AMBRIZ ◽  
Jennifer GUEVARA ◽  
Karima G. LÓPEZ ◽  
Marina RODES-BLANCO ◽  
...  
Keyword(s):  
Species Composition ◽  
Habitat Loss ◽  
Forest Cover ◽  
Landscape Fragmentation ◽  
Dung Beetles ◽  
Landscape Configuration ◽  
Edge Density ◽  
Logistic Regression Models ◽  
Habitat Loss And Fragmentation ◽  
Taxonomic Groups

ABSTRACT Habitat loss and fragmentation caused by deforestation are important anthropogenic drivers of changes in biodiversity in the Amazon rainforest, and has reached its highest rate in recent decades. However, the magnitude and direction of the effects on species composition and distribution have yet to be fully understood. We evaluated the responses of four taxonomic groups − birds, amphibians, orchid bees, and dung beetles - to habitat loss and fragmentation at both species and assemblage level in the northern Ecuadorian Amazon. We sampled fifteen 250-m long plots in terra-firme forest remnants. We calculated one landscape fragmentation index (fragindex), which considers the proportion of continuous forest cover, edge density and isolation in the landscape, and nine landscape configuration metrics. Logistic regression models and multivariate regression trees were used to analyze species and assemblage responses. Our results revealed that over 80% of birds, amphibians or orchid-bee species, and 60% of dung beetles were negatively affected by habitat loss and fragmentation. Species composition of all taxonomic groups was significantly affected by differences in forest cover and connectivity. Less than 5% of all species were restricted to landscapes with fragindex values higher than 40%. Landscape metrics related to the shape and area of forest patches determined the magnitude and direction of the effect on species responses. Therefore, changes in the landscape configuration of Ecuadorian Amazonia should be minimized to diminish the effects of habitat loss and fragmentation on species occurrence and assemblage composition.

Ecology of the Atlantic Forest

Ecology ◽  
2021 ◽  
Author(s):  
Elise Damstra ◽  
Cristina Banks-Leite
Keyword(s):  
Atlantic Forest ◽  
Forest Cover ◽  
Time Lag ◽  
Native Forest ◽  
Important Species ◽  
Habitat Transformation ◽  
Golden Lion Tamarin ◽  
Palm Heart ◽  
In The Wild ◽  
Unique Domain

Extending along the southern coast of Brazil, into Argentina and Paraguay, the Atlantic Forest is a domain that once covered 150 Mha and includes many distinct forest subtypes and ecosystems. Its large latitudinal (29˚) and altitudinal (0–2,800 m above sea level) range, as well as complex topography in the region, has created microclimates within forest subtypes, which has led to biodiversity specifically adapted to narrow ecological ranges. The region is incredibly species-rich and is home to charismatic or economically important species such as the black and golden lion tamarin, the red-browned Amazon parrot, and the highly prized palm heart from Euterpe edulis. Through widespread human-driven change dating back to the arrival of European settlers in 1500, this realm has been extensively reduced, fragmented, and modified. Nowadays, this region is home to about 130 million people (60 percent of the Brazilian population) and is responsible for producing 70 percent of Brazil’s GDP, putting a strain on natural resources and providing challenges to conservation. Due to its high levels of endemic species coupled with a high threat of habitat loss and fragmentation, the Atlantic Forest has been identified as a “biodiversity hotspot.” Numerous studies have assessed the effects of habitat transformation on biodiversity and the consensus is that the majority of species are negatively affected. It is puzzling however that few species have actually gone extinct in the wild, even if some extinctions might have gone undetected. Extinctions do not immediately follow habitat change, there is often a time lag of many decades between habitat transformation and extinction. This may suggest that many species in the Atlantic Forest are “living deads,” as despite their presence the available habitat no longer supports their requirements. It also suggests that there is a window of opportunity to restoring the domain to avert extinctions before they are realized. Current research and policy actions are geared toward optimizing restoration and increasing the extent of native forest cover, bringing hope to the conservation of this unique domain.

Applying sustainability indicators in the analysis and segmentation of tourist demand - implications for marine visitor experiences on the Tremiti Islands, Italy.

2021 ◽  
pp. 192-204
Author(s):  
Nicolaia Iaffaldano ◽  
Sonia Ferrari
Keyword(s):  
National Park ◽  
Marine Reserve ◽  
Sustainability Indicators ◽  
High Quality ◽  
Visitor Experiences ◽  
Different Types ◽  
The Matrix ◽  
Crucial Information ◽  
Tourist Demand ◽  
Questionnaire Research

Abstract This chapter presents the findings of qualitative questionnaire research carried out in the Tremiti Islands Marine Reserve, which is part of Gargano National Park, Italy. The study have identified different segments of tourists visiting Tremiti by means of the model proposed by Arnegger et al. (2010), using the matrix suggested in the model. The model was used to understand and categorize visitor characteristics, their expectations and levels of satisfaction, and the strengths and weaknesses of local offerings. This is crucial information for the managers of the marine reserve who require thorough knowledge of the different types of visitors to adapt to the needs, expectations and preferences of the visitors in order to offer high-quality services and memorable experiences.

scholarly journals Nursery Cultural Techniques Facilitate Restoration of Acacia koa Competing with Invasive Grass in a Dry Tropical Forest

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1124
Author(s):  
Douglass F. Jacobs ◽  
Anthony S. Davis ◽  
R. Kasten Dumroese ◽  
Owen T. Burney
Keyword(s):  
Forest Restoration ◽  
Forest Cover ◽  
Seedling Survival ◽  
Tree Canopy ◽  
Anthropogenic Activity ◽  
Native Forest ◽  
Forest Trees ◽  
Acacia Koa ◽  
Mean Values ◽  
Kikuyu Grass

Anthropogenic activity has caused persistent and prominent losses of forest cover in dry tropical forests. Natural regeneration of forest trees in grazed areas often fails due to lack of seed sources and consumption by ungulates. To address this, the effective restoration of such sites often requires fencing and outplanting nursery-grown seedlings. In the degraded, dry forests of tropical Hawaii, USA, an additional challenge to restoration of native forest trees is the introduced kikuyu grass (Cenchrus clandestinus). This invasive, rapidly growing rhizomatous plant forms deep, dense mats. We studied the use of nursery cultural techniques to facilitate the establishment of koa (Acacia koa) seedlings outplanted amidst well-established kikuyu grass on a volcanic cinder cone on the dry, western side of Hawaii Island. Seedlings were grown four months in three container sizes (49, 164, 656 cm3) and with four rates (0, 4.8, 7.2, and 9.6 kg m−3) of 15–9–12 (NPK) controlled-release fertilizer incorporated into media prior to sowing. After 16 months in the field, seedling survival was > 80% for all treatments with two exceptions: the non-fertilized 49 cm3 (78%) and 164 cm3 (24%) containers. After 10 years, only these two treatments had significantly lower survival (35% and 10%, respectively) than the other treatments. One year following planting, none of the non-fertilized seedlings had transitioned to phyllodes from juvenile true leaves, regardless of container size. For the fertilized 656 cm3 container treatment, 78%–85% of seedlings had phyllodes, with mean values increasing by fertilizer rate. Phyllodes are known to confer greater drought resistance than true leaves in koa, which may help to explain the improved survival of fertilized trees on this relatively dry site. Overall, nursery fertilization was more influential on seedling height and diameter response than container size after outplanting. However, the largest container (656 cm3) with the addition of fertilizer, produced significantly larger trees than all other treatments during the early regeneration phase; early growth differences tended to fade at 10 years due to inter-tree canopy competition. Although koa is able to fix atmospheric nitrogen through rhizobium associations, our data confirm the importance of nursery fertilization in promoting regeneration establishment. Nursery cultural techniques may play an important role in forest restoration of dry tropical sites invaded by exotic vegetation.

scholarly journals Impacts of deforestation on water balance components of a watershed on the Brazilian East Coast

2014 ◽  
Vol 38 (4) ◽  
pp. 1350-1358 ◽  
Author(s):  
Donizete dos Reis Pereira ◽  
André Quintão de Almeida ◽  
Mauro Aparecido Martinez ◽  
David Rafael Quintão Rosa
Keyword(s):  
Water Balance ◽  
Forest Cover ◽  
East Coast ◽  
Swat Model ◽  
Native Forest ◽  
Efficiency Coefficient ◽  
Water Balance Components ◽  
The Real ◽  
Calibration And Validation ◽  
Creek Watershed

The Brazilian East coast was intensely affected by deforestation, which drastically cut back the original biome. The possible impacts of this process on water resources are still unknown. The purpose of this study was an evaluation of the impacts of deforestation on the main water balance components of the Galo creek watershed, in the State of Espírito Santo, on the East coast of Brazil. Considering the real conditions of the watershed, the SWAT model was calibrated with data from 1997 to 2000 and validated for the period between 2001 and 2003. The calibration and validation processes were evaluated by the Nash-Sutcliffe efficiency coefficient and by the statistical parameters (determination coefficient, slope coefficient and F test) of the regression model adjusted for estimated and measured flow data. After calibration and validation of the model, new simulations were carried out for three different land use scenarios: a scenario in compliance with the law (C1), assuming the preservation of PPAs (permanent preservation areas); an optimistic scenario (C2), which considers the watershed to be almost entirely covered by native vegetation; and a pessimistic scenario (C3), in which the watershed would be almost entirely covered by pasture. The scenarios C1, C2 and C3 represent a soil cover of native forest of 76, 97 and 0 %, respectively. The results were compared with the simulation, considering the real scenario (C0) with 54 % forest cover. The Nash-Sutcliffe coefficients were 0.65 and 0.70 for calibration and validation, respectively, indicating satisfactory results in the flow simulation. A mean reduction of 10 % of the native forest cover would cause a mean annual increase of approximately 11.5 mm in total runoff at the watershed outlet. Reforestation would ensure minimum flows in the dry period and regulate the maximum flow of the main watercourse of the watershed.

Evidence for multiple drivers of aerial insectivore declines in North America

The Condor ◽  
2019 ◽  
Vol 121 (2) ◽  
Author(s):  
Kimberly J Spiller ◽  
Randy Dettmers
Keyword(s):  
North America ◽  
Habitat Loss ◽  
Prey Abundance ◽  
Research Progress ◽  
Current Evidence ◽  
High Quality ◽  
Prey Quality ◽  
Aerial Insectivore ◽  
Starting Point ◽  
Aerial Insectivores

Abstract Aerial insectivores (birds that forage on aerial insects) have experienced significant population declines in North America. Numerous hypotheses have been proposed for these declines, but current evidence suggests multiple factors could be operating in combination during their annual migratory cycles between breeding and nonbreeding areas. Potential drivers include decreased prey abundance, direct or indirect impacts of environmental contaminants, habitat loss, phenological changes due to warming climate, and conditions on migratory stopover or wintering grounds. While no single threat appears to be the cause of aerial insectivore declines, existing evidence suggests that several of these factors could be contributing to the declines at different times in the annual lifecycle. Breeding productivity for most of these species does not appear to be limited by overall prey abundance, contaminants, or habitat loss, which suggests that similar issues on nonbreeding grounds or carryover effects could play important roles. However, a better understanding of the importance of prey quality throughout the lifecycle is critically needed. Based on current evidence, we propose that changes in availability of high-quality prey, with variability across breeding and nonbreeding grounds, reduce various combinations of fledging success, post-fledging survival, and nonbreeding season body condition of aerial insectivores, resulting in species and geographic differences in population trends. We encourage others to use this hypothesis as a starting point to test specific mechanisms by which availability of high-quality prey influences demographic parameters. We suggest that future research focus on defining prey quality, monitoring insect abundance in conjunction with birds, comparing demographic models across local populations experiencing different population growth rates, and using tracking technology to document important migratory and nonbreeding areas. Considerable research progress already has been made, but additional research is needed to better understand the complex web of potential causes driving aerial insectivore declines.

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