Habitat loss and fragmentation

Top PDF Habitat loss and fragmentation:

The relevance of burial to evade acorn predation in an oak forest affected by habitat loss and land use changes

The relevance of burial to evade acorn predation in an oak forest affected by habitat loss and land use changes

The relevance of seed burial as a mechanism to evade predators, however, may be compromised in forest ecosys- tems affected by human activities, and this proposal is supported by two main arguments. On the one hand, seed consumers in fragmented forests preferentially feed at the interior of forest patches. Small mammals, for instance, focus their foraging activities within the patches and avoid moving across anthropogenic matrices because this later habitat offers scarce opportunities to evade their predators (Tellería et al., 1991; Nupp and Swihart, 2000; Rizkalla and Swihart, 2007). As a consequence of this behavior, seed consumers are concentrated within the patches and this elevates consumer pressure on seed banks, as compared to seed banks in the surrounding matrix habitat (Muñoz and Bonal, 2011). On the other hand, the environmental changes associated to forest fragmentation can dramatically reduce the reproductive success of trees within remnant patches (Rocha and Aguilar, 2001; Burgos et al., 2008; Vesk et al., 2010; Barbeta et al., 2011), and this could be translated in lower availability of food resources for seed consumers. In this latter scenario, and once consumers have depleted seed banks on the soil surface, pilferage of seeds that are already buried may start to occur within forest patches. Moreover, this scarcity of food resources within forest patches may also force seed consumers to explore the surrounding ma- trix habitat in search of new sources of food (Bustamante et al., 2012). By following these lines of reasoning, it can be proposed that seeds exposed on the soil surface should experience higher consumption rates than buried seeds at the interior of forest patches, and this would occur because exposed seeds are easier to fi nd by consumers. However, pilferage of buried seeds should start within forest patches when seeds on the soil surface become scarce. This deple- tion of seed banks within forest patches may also obligate consumers to move across the matrix habitat in search of seeds, but seed consumption rates in this latter habitat must
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11 Lee mas

Habitat disturbance in Mediterranean landscapes:Effects of fire and fragmentation on birds

Habitat disturbance in Mediterranean landscapes:Effects of fire and fragmentation on birds

the overall pattern and the results of our study were very similar to these obtained by Diaz et al. (1998), who found that fragment size also accounted for about 70 % of the variation in forest bird species of pine forest plantations in the Spanish plateaux. Decreases in forest area decrease the number of species in the remnant fragments, mainly because of the loss of habitat (ex. random sample hypothesis, Connor & McCoy 1979), but also because of the indirect effects of fragmentation on the spatial arrangement of remnant forest patches, such as increased isolation or an increase in edge area (Van Dorp & Opdam 1987, Opdam 1991, Saunders et al. 1991, Forman 1995). Indeed, in the Penedes area, distance to corridors significantly affected forest bird presence in fragments, which suggests that the indirect effects of fragmentation such as isolation are also involved in the determination of patterns of species loss in the Mediterranean forests analysed. The fact that distance to continuous forest habitats was also included in some of the specific models of species presence further supports that, at least for some species, isolation partly determines their ability to occupy patches in fragmented Aleppo pine forests. However, the exact effect of stochastic processes on species loss and to which extent this is affected by isolation in Mediterranean forests remains unknown (but see Tellería & Santos 1999). Future studies on the independent assessment of stochastic processes from isolation in species loss are required in order to predict the exact role of fragmentation in bird distribution (Opdam 1991). The role of other indirect effects of fragmentation on species loss can not be ruled out completely but is difficult to quantify in the present study. In particular, in fragmented forest in North America, increased nest predation near forest edges seems to be an important factor behind decreased habitat quality (Wilcove 1985, Donovan et al. 1995, Robinson et al. 1995). But similar studies in Mediterranean habitats do not unambiguously support this negative effects and even found that nest predation is higher in forest interior compared to edge habitats (Santos & Tellería 1992). Therefore, the role of indirect edge effects (Murcia 1995), such as nest predation, in Mediterranean fragmented forests remains obscure and waiting for studies that assess simultaneously and identify their relative influence on bird communities.
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123 Lee mas

Fragmentation modulates the strong impact of habitat quality and plant cover on fertility and microbial activity of semiarid gypsum soils

Fragmentation modulates the strong impact of habitat quality and plant cover on fertility and microbial activity of semiarid gypsum soils

The lack of direct effect of water availability could be explained by the different time scale at which this driver can impact on ecosystem properties. For exam- ple, in our study case, the 2 years of manipulative changes in water availability contrasts with the long term processes associated with loss of habitat quality. Nutrient availability usually shows a lagged response to climatic variations, sometimes taking even decades to respond to environmental variation in the case of so-called slow variables (Reynolds et al. 2007). How- ever, enzymatic activities are rapid soil functional surrogates and therefore short-term effects of our wa- ter treatment can be expected. We did not detect these effects for the different water treatments due to our experiment mimicking either a mild or too short drought or a drought not affecting soils at the most responsive time of the year; it must be noted, however, that our drought simulation was guided both in extent Fig. 3 Soil enzyme activity across treatments. a β -Glucosidase;
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11 Lee mas

HABITAT III POLICY PAPER 8 – URBAN ECOLOGY AND RESILIENCE

HABITAT III POLICY PAPER 8 – URBAN ECOLOGY AND RESILIENCE

This paper’s discussion of urban ecology and resilience is relevant to the achievement of the United Nations Sustainable Development Goals. The SDGs underscore the importance of joint action – including by local governments – to address global environmental issues. While all the SDGs have important links to the topic of this policy unit, thematically, the discussion in this paper is most relevant to SDG 2 on food security; SDG 3 on health, SDG 6 on sustainable management of water; SDG 7 on sustainable energy sources; SDG 9 on resilient infrastructure; SDG 11 on sustainable and resilient human settlements; SDG 12 on sustainable consumption and production; and SDG 13 on climate change (see: sustainabledevelopment.un.org/sdgs). In addition, the Sendai Framework relates specifically to resilience by providing a global blueprint for managing disaster risks (see: unisdr.org/we/coordinate/sendai-framework). Its first four targets: to reduce (1) mortality, (2) affected populations, (3) economic losses, and (4) damage to critical infrastructure, also align closely with several SDG targets. Both the SDGs and the Sendai Framework principles and approaches to adaptation are fully embedded in the Paris Agreement adopted at the 21 st Conference of Parties of the
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44 Lee mas

HABITAT III POLICY PAPER 9 – URBAN SERVICES AND TECHNOLOGY

HABITAT III POLICY PAPER 9 – URBAN SERVICES AND TECHNOLOGY

A quarter of the global population live in developing countries that face water shortages due to weak governance, deficiencies of professional capacities and a lack of infrastructure for water transport and treatment (WWAP 2015). Almost a fifth of the world´s population (1.2 billion people) live in areas with physical water scarcity (UN-Water/FAO, 2007). 748 million people lack access to an improved drinking water source, while 1.8 billion people are without safe drinking water (WHO 2014, pg. 1). In 2012, 2.5 billion people had no access to an improved sanitation facility. One billion people do not use any sanitation facility, defecating instead in the open (SDG 2015); consequences for water and health are severe. By 2050, global water demand is projected to increase by 55%, driven mainly by manufacturing, thermal electricity generation and domestic use (WWAP 2015). Increased demand for water can indicate positive economic growth but also implies huge challenges in allocating scarce water between and within industry, agriculture and the minor but yet decisive share of domestic water use. Increased water demand often marginalises the poor population and excludes it from safe water accessibility. The convergence of climate change and growing economic development in least developed countries is to intensify the water insecurity of the poor. The OECD (2012) estimates that by 2050, water demand from manufacturing industries and thermal power generation will increase dramatically, especially in developing countries and the BRICS. In the manufacturing industry alone, the total share of water demand by 2050 is expected to increase from 7% to 22% (WWAP 2015). In spite of outstanding advances in water provision in the last decades, over 80% of wastewater worldwide is not collected or treated, and urban areas are the main source of pollution. 90% of all wastewater in developing countries is discharged untreated directly into rivers, lakes or the oceans, causing environmental and health risks. (WWDR 2015)
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35 Lee mas

Avoiding, mitigating, and compensating for loss and degradation of wetlands in national laws and policies

Avoiding, mitigating, and compensating for loss and degradation of wetlands in national laws and policies

lands. To enable the Environmental Protection Agency to make this assessment, an applicant must submit a re- port that contains a commitment “to avoid any adverse environmental effects which can be avoided on the im- plementation of the undertaking … [and] to address un- avoidable environmental and health impacts and steps where necessary for their reduction.” The report must also suggest “alternatives to the establishment of the undertaking.” Ghana’s Strategic Environmental Assess- ment (SEA) Manual (2004) defines mitigation measures as “[m]easures that avoid, reduce, remediate or com- pensate for the negative impacts of a strategic action.” Namibia: The Environmental Management Act (2007) requires Environmental Assessments for all projects that may “have significant effects on the environment or the use of natural resources.” Among the principles of environmental management set forth in the Act are the prevention of damage to the environment and the reduction, limitation, or control of activities causing en- vironmental damage. In practice, this can lead to or en- courage an avoid-mitigate-compensate approach. For example, a Strategic Environmental Assessment for the central Namib Uranium Rush (2010) calls for the avoid- ance, minimization, mitigation/and or restoration of biodiversity impacts, as well as the implementation of biodiversity offsets.
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12 Lee mas

Self-regulation, Self-efficacy and Nutritional Orientation for Weight Loss

Self-regulation, Self-efficacy and Nutritional Orientation for Weight Loss

El análisis de diferencias de medias en el grupo experimental mostró una disminución en las medias de la antropometría y aumento en las medias de los niveles de autorregulación y auto[r]

8 Lee mas

Fragmentation and human disturbances in peri-urban forests: effects on vascular flora

Fragmentation and human disturbances in peri-urban forests: effects on vascular flora

Distance to the edge has been traditionally used to predict edge effects. Species richness of different plant groups responds differently to distance from edges (Murcia 1995; Pauchard & Alaback 2004; Moffatt et al. 2004; Holt et al. 2005). We have found that this response also depends on forest-size category, being significant for small patches but not for large forest areas in the case of synanthropic plants, and vice versa in the case of forest plants. In general, results from edge-to-interior studies indicate that the number of ruderal and exotic species is highest at edges and tends to decline towards the interior (Fraver 1994; Pauchard & Alaback 2004). However, distance to the edge was not significant for synanthropic species richness in large forest areas of the Vallès, perhaps because these large forests have, on average, few synanthropic species (Fig 4a). In the case of forest species, large peripheral zones inside the patches are often needed to detect changes in richness and composition between edge and core in highly disturbed peri-urban areas (Ranney et al. 1981; Laurence & Yensen 1991; Honnay et al. 1999c). Similar results were found for arthropods in large and small forest patches in the Sydney region (Australia, Gibb & Hochuli 2002), confirming that the effects of human impact in urban and sub-urban forests occur deeper into the forest than in more rural forest-cropland mosaics (Matlack 1993), though patterns of variation can vary among taxonomic groups (Gibb & Hochuli 2002).
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148 Lee mas

Habitat suntuario

Habitat suntuario

La definición del diccionario esencial de la Real Academia Españo- la de la palabra suntuario es “aquello perteneciente o relativo al lujo.”Para real- mente comprender el concepto del habitat suntuario, del habitat de lo lujoso, du- rante la investigación nos remontamos a sus origenes en la historia del hombre. La misma nos llevó al nacimiento de la clase ociosa, generalmente aso- ciada a la vida de lujo. La intención siempre fue buscar comprender la mentali- dad del individuo por detrás de lo lujoso. A traves de determinados autores como Thorstein Veblen y su libro “Teoría de la clase ociosa” o el sociólogo Sygmunt Bau- man y sus pensamientos pudimos adentrarnos de a poco en este mundo del lujo. A lo largo de la historia siempre existió esta diferenciación de clas- es que se manifestaba en la arquitectura, donde el usuario buscaba dejar un lega- do, manifestar su poder, poseer lo que otros no pueden. El concepto de lo privili- giado, lo unico, lo excentríco, de poseer lo que pocos pueden poseer; y de mostrarlo.
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61 Lee mas

Habitat suntuario

Habitat suntuario

Por lo tanto, para hacerlo aún más excéntrico, se planteó el siguiente tema: “Un fanático multimillonario encarga, para el club del cual es fan, un centro de alto rendimiento deportiv[r]

55 Lee mas

Considerations on bubble fragmentation models

Considerations on bubble fragmentation models

Finally, in §5 we intégrate the population balance equation to determine the evolution of the distribution of bubbles in a turbulent water jet using different models for the daughter-b[r]

19 Lee mas

Weight Loss (Spanish)

Weight Loss (Spanish)

El Registro Nacional para el Control de Peso (NWCR por sus siglas en inglés) lo constituye un grupo de personas que han perdido en promedio más de 60 libras y no lo han recuperado por [r]

5 Lee mas

Wood thermodegradation: experimental analysis and modeling of mass loss kinetics

Wood thermodegradation: experimental analysis and modeling of mass loss kinetics

Wood thermodegradation is a complex set of degradation and polymerization reactions giving several reaction products (Nguila et al. 2009, Weiland et al. 1998). Knowledge of kinetic schemes describing the thermodegradation process is required for elaboration of predicting tools allowing controlling wood heat treatment. Mathematical modeling of occurring coupled heat and mass transfers are a simplified approximation of real phenomena. Variety of methods based on the thermal analysis of polymer thermodegradation has been developed. An overview of required measurement, kinetic analysis of solid state reaction leading the determination of the reaction order and parameterization of the reaction rate, method’s advantages and drawbacks has been proposed in the literature (Liu and Fan 1999, Brown et al. 2000, Vyazovkin et al. 2011). There could be cited the isothermal and the constant heating rate methods (Freeman and Carroll 1958, Coats and Redfern 1964), the multiple heating rate model (Kissinger 1957). Modeling of polymer thermodegradation is often based on global kinetics, since trying to represent full complexity of the process makes no sense. Global kinetics uses the key steps in the overall mass loss process. There is an ongoing debate concerning the determination of the kinetic parameters of the global reactions of wood pyrolysis (Prins et al. 2006, Di Blasi and Lanzetta 1997, Rousset et al. 2006, Grioui et al. 2006). Models available in the literature usually assume that kinetics of all the thermodegradation reactions obey an Arrhenius low defined by its kinetic constant and activation energy (Koufopanos et al. 1991, Prins et al. 2006, Di Blasi and Lanzetta 1997, Rousset et al. 2006, Grioui et al. 2006).
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16 Lee mas

Effect of particle shape and fragmentation on the response of particle dampers

Effect of particle shape and fragmentation on the response of particle dampers

A particle damper (PD) is a device that can atten- uate mechanical vibrations thanks to the dissipa- tive collisions between grains contained in a cavity attached to the vibrating structure. It has been re- cently suggested that, under working conditions in which the damping is optimal, the PD has a univer- sal response in the sense that the specific dissipa- tive properties of the grains cease to be important for the design of the device. We present evidence from simulations of PDs containing grains of dif- ferent size, shape and restitution coefficient, that the universal response is also valid when fragmen- tation of the grains occurs (generally due to inten- sive operation of the PD). In contrast, the welding of grains (caused by operation under high tempera- tures) can take the PD out of the universal response and deteriorate the attenuation. Interestingly, we observed that even at working conditions off the optimal damping, the shape of the grains remains unimportant for the response of the PD.
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11 Lee mas

Melatonin reduces neuronal loss and cytoskeletal deterioration: implications for psychiatry

Melatonin reduces neuronal loss and cytoskeletal deterioration: implications for psychiatry

This review article summarizes the potential role of circadian rhythmicity and melatonin in psychiatric disorders. The melatonin rhythm, with high blood levels at night and low values during the day, is a reflection of the biological clock, i.e., the suprachiasmatic nucleus (SCN). The SCN receive information about the prevailing light: dark conditions from specialized ganglion cells (only 1-2% of the total ganglion cells) in the retina. These unique cells contain a newly-discovered photopigment, melanopsin, which responds to a rather narrow band width of light that peaks at roughly 480 n m . T h e a x o n s o f t h e s e g a n g l i o n c e l l s p r o j e c t v i a t h e retinohypothalamic tract through the optic nerve to the SCN, located just above the optic chiasm in the anterior hypothalamus. Via this pathway, light detected by the retina synchronizes the circadian clock to precisely 24 hours. In the absence of light, i.e., darkness, the SCN signals the pineal gland to produce melatonin via a complex neural pathway that involves fibers that project from the hypothalamus to the preganglionic sympathetic neurons in the intermediolateral cell column of the upper thoracic cord. Axons of these neurons exit the spinal cord to eventually synapse on neurons in the superior cervical ganglia. Then, postganglionic fibers convey the information to the pineal gland mediating the nighttime rise in melatonin synthesis. Because melatonin is only elevated at night, it is referred to as the «chemical expression of darkness». Disturbances in the rhythmicity of the biological clock and/or the melatonin rhythm likely contribute to psychophysiological disturbances and mood disorders.
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9 Lee mas

Measurement and analysis of extra propagation loss of tunnel curve

Measurement and analysis of extra propagation loss of tunnel curve

In order to extract the extra loss of the tunnel curve from the total received power, a ray-tracing simulator is employed to simulate the reference received signal power by assuming the curved tunnel to be straight. The validity of the ray-tracing sim- ulator in both straight and curved tunnels at different frequen- cies and polarizations is verified by extensive comparisons with various measurements. Fig. 8(a)-(c) are the three instances. Fig. 8(a) shows the comparison on the received power between the measurement and the ray-based simulation in the straight arched "type I" tunnel at 920 MHz with V-pol. The simulator used in this paper is developed in the project TECRAIL [45], based on the image theory, taking into account the antenna patterns, geometry of the tunnel, locations of Tx and Rx, var- ious orders of reflections, and the first order of diffraction. By simulating with three to eight order reflections, we obtain some differences from three to five order reflections but very similar results when using five order or higher order reflections. Since edges are note modeled in the straight tunnel, the diffraction calculation can be eliminated, and considerable computational speed up can be achieved. In the test, simulations with and with- out diffraction are compared, and the results are very similar. Thus, the ray-based simulations in this paper are with five order reflections and without diffraction, for the sake of the tradeoff between computational load and accuracy. Correspondingly, Fig. 8(b) and (c) shows the comparison in the curved arched
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11 Lee mas

EL DESAFIO DE LA AUTOPRODUCCIÓN DEL HABITAT

EL DESAFIO DE LA AUTOPRODUCCIÓN DEL HABITAT

This article discusses some ideas about setting self production. Among these ideas as part of the historical experience of the city of Iquique, land occupation and urban lay out are the mostoutstanding ones. The article ends up pointing out the feltneed for technical criteria foradequate setting planning. lt cites Alto Hospicio as an example of setting selfproduction in which the basic housing unit turns out to be the axis of an orderly population growth.

12 Lee mas

BASORA HABITAT. .es. Residencial

BASORA HABITAT. .es. Residencial

La información requerida por el Real Decreto 515 de 21/04/1989, sobre la defensa de los consumidores en cuanto a la información a suministrar, se encuentra a su disposición en las ofici[r]

18 Lee mas

Día mundial del habitat

Día mundial del habitat

En términos urbanos la sostenibilidad supone una gestión y desarrollo integral de los asentamientos humanos orientado, como señaló el Secretario General de la ONU con motivo del último D[r]

11 Lee mas

Borders within border: Fragmentation, Disposition,  Connection

Borders within border: Fragmentation, Disposition, Connection

Urban territory of Belgrade is positioned at the mouth of the two rivers, which is a significant factor in its definition and interpretation. During the research of historical, political and constructional conditions in the capital’s development, the spatial-morphological unit of New Belgrade was separated. The sixties and the seventies of the twentieth century were the time of intense construction of this part of the city. In an attempt to keep up with the current world trends and influenced by the ruling ide- ology, domestic architects were developing an architecture that reflected a new, avant-garde, progressive and free society. The sculpturality of the form and the brutal-shaped objects were particularly supported, because they were giving the impression of wanted monumentality. Over time, objects built in this manner became the landmarks of their surround- ings. The subject of this paper are issues in relation between the public urban space and the everyday life of the society. A four market centers („Fontana“, „Stari Merkator“, „Delta“ and „Ušće“) built on the territory of New Belgrade are distinguished as representatives of the observed issues. Changes in the appearance of this type of public space and their relation to the given local context will be analyzed through four chosen examples. The main aim of the research is to improve knowledge about patterns of public spaces usage for the purpose of collective gatherings. Through the applicable typology of architectural objets, the spatial forms of the men- tioned trade centers will be define. The causes of the lack of awareness about their significance and devastation of their spatial forms and utility will be examined by revealing the connections between architectural cre- ativity and the wider social and cultural changes caused by the commer- cialization of taste.
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