Birds as Suppliers of Seed Dispersal in Temperate Ecosystems: Conservation Guidelines from Real‐World Landscapes

Abstract: Seed dispersal by animals is considered a pivotal ecosystem function that drives plant‐community dynamics in natural habitats and vegetation recovery in human‐altered landscapes. Nevertheless, there is a lack of suitable ecological knowledge to develop basic conservation and management guidelines for this ecosystem service. Essential questions, such as how well the abundance of frugivorous animals predicts seeding function in different ecosystems and how anthropogenic landscape heterogeneity conditions the role of dispersers, remain poorly answered. In three temperate ecosystems, we studied seed dispersal by frugivorous birds in landscape mosaics shaped by human disturbance. By applying a standardized design across systems, we related the frequency of occurrence of bird‐dispersed seeds throughout the landscape to the abundance of birds, the habitat features, and the abundance of fleshy fruits. Abundance of frugivorous birds in itself predicted the occurrence of dispersed seeds throughout the landscape in all ecosystems studied. Even those landscape patches impoverished due to anthropogenic disturbance received some dispersed seeds when visited intensively by birds. Nonetheless, human‐caused landscape degradation largely affected seed‐deposition patterns by decreasing cover of woody vegetation or availability of fruit resources that attracted birds and promoted seed dispersal. The relative role of woody cover and fruit availability in seed dispersal by birds differed among ecosystems. Our results suggest that to manage seed dispersal for temperate ecosystem preservation or restoration one should consider abundance of frugivorous birds as a surrogate of landscape‐scale seed dispersal and an indicator of patch quality for the dispersal function; woody cover and fruit resource availability as key landscape features that drive seedfall patterns; and birds as mobile links that connect landscape patches of different degrees of degradation and habitat quality via seed deposition.     

Floristic composition of arid off –shore islands in Abu Dhabi,United Arab Emirates

Data on flora and vegetation of 14 off-shore islands representing different habitat types were studied for investigating floristic composition, vegetation types and correlation with their habitats and ecosystem. The results demonstrate considerable plant distribution and diversity among the islands within the limited spectrum of species; encompassing a total of 47 species, belonging to 43 genera under 24 families. The most representative families were Amaranthaceae (9 species), Fabaceae (4 species), Poaceae (4 species) and Asteraceae and Aizoaceae (3 species each). Fourteen families are represented by only one species. The mangrove species, Avicennia marina, occurs throughout the coast of Abu Dhabi in discontinuous patches and in different water salinities. The studies also seek to underline that dominant species that constitutes the flora of Abu Dhabi are salt tolerant in nature. Compared to other Arabian Peninsula ecosystems, UAE perhaps has a higher coastal: mainland area ratio, which has contributed to a natural dominance of salt tolerant species among the community. The studies show 40% similarity among islands with respect to the species diversity. The floristic composition of the off-shore islands also indicates a need to consider these sites as protected sites.     

POLLUTION THREATS IN THE MEDITERRANEAN SEA: AN OVERVIEW

This overview summarises the present knowledge on major sources of pollution, which are of concern for the Mediterranean Sea. Eutrophication, red tides, organic loads, hydrocarbon spills, heavy metal contamination and their biological effects are described on the light of the ecological characteristics of the Mediterranean. In particular special attention is paid to the "new pollution" processes; i.e. , the introduction of novel substances with biological activity that might have synergetic effects with "classical pollutants". Different compartments and marine ecosystems are considered and compared. The degree of anthropogenic impact and its apparent trends are discussed. Possible monitoring plans and remedial actions for a sustainable management of coastal zones subjected to increasing pollution are also suggested.     

生态恢复对退化河岸植物群落的作用 ——以重庆九龙外滩河岸带生态恢复为例

河岸带是陆地生态系统与水生生态系统之间的过渡地带,受人类干扰的威胁较大.长江是流经重庆都市区的主要河流,主城区两江四岸部分河岸硬化,河岸生态功能退化或丧失,生物多样性降低.本文以重庆主城区九龙外滩的河岸带为研究区域,通过调查,采用Ward最小方差法对植物群落类型进行划分,比较了生态恢复区域和自然区域的植物群落特征及优势...     

Pollution threats in the Mediterranean Sea: An overview

This overview summarises the present knowledge on major sources of pollution, which are of concern for the Mediterranean Sea. Eutrophication, red tides, organic loads, hydrocarbon spills, heavy metal contamination and their biological effects are described on the light of the ecological characteristics of the Mediterranean. In particular special attention is paid to the "new pollution" processes; i.e. , the introduction of novel substances with biological activity that might have synergetic effects with "classical pollutants". Different compartments and marine ecosystems are considered and compared. The degree of anthropogenic impact and its apparent trends are discussed. Possible monitoring plans and remedial actions for a sustainable management of coastal zones subjected to increasing pollution are also suggested.     

Mapping woodland vegetation in SW Ethiopia based on a hybrid model

SUMMARY

Despite the fact that indigenous inhabitants have sustainably managed the forests and woodlands for centuries, Ethiopia's woodland resources are now under severe pressure. At the request of the Ethiopian Government, in 1996/97 the Savanna Woodland Management Study Project was initiated by the German Technical Cooperation (GTZ). A detailed analysis of the woodland resources in SW Ethiopia and a vegetation map were produced. The map was generated using multispectral remote-sensing data, and provides details of the variety within Ethiopian woodlands. A hybrid data classification procedure was applied to incorporate relief and climatic conditions. After analysis of the remote sensing data by image processing, a spatial overlay was performed to incorporate the additional site condition factors. The vegetation map shows the spatial distribution of all existing woodland types in the area and enhances our knowledge of the rich biodiversity of SW Ethiopia. Such mapping gives us a better understanding of existing ecosystems and indigenous land-use systems, and hence, can lead to more sustainable management of the natural resources in the future.     

Expanding the Global Network of Protected Areas to Save the Imperiled Mediterranean Biome

Abstract:  Global goals established by the Convention on Biological Diversity stipulate that 10% of the world's ecological regions must be effectively conserved by 2010. To meet that goal for the mediterranean biome, at least 5% more land must be formally protected over the next few years. Although global assessments identify the mediterranean biome as a priority, without biologically meaningful analysis units, finer-resolution data, and corresponding prioritization analysis, future conservation investments could lead to more area being protected without increasing the representation of unique mediterranean ecosystems. We used standardized analysis units and six potential natural vegetation types stratified by 3 elevation zones in a global gap analysis that systematically explored conservation priorities across the mediterranean biome. The highest levels of protection were in Australia, South Africa, and California-Baja California (from 9–11%), and the lowest levels of protection were in Chile and the mediterranean Basin (<1%). Protection was skewed to montane elevations in three out of five regions. Across the biome only one of the six vegetation types—mediterranean shrubland—exceeded 10% protection. The remaining vegetation types—grassland, scrub, succulent dominated, woodland, and forest—each had <3% protection. To guard against biases in future protection efforts and ensure the protection of species characteristic of the mediterranean biome, we identified biodiversity assemblages with <10% protection and subject to >30% conversion and suggest that these assemblages be elevated to high-priority status in future conservation efforts.     

The meaning of mainland Portugal beaches and dunes’ psammophilic plant communities: a contribution to tourism management and nature conservation

Due to their position of interface between the sea and land, the flora and vegetation of coastal beaches and dunes, occupy ecologically extreme, sensitive, unique and valuable habitats. The occurrence of a large number of endemic taxa and specific plant associations endowed with key ecological services and adapted to a stressful and harsh environmental gradient, gives them a high interest for nature conservation and an important role in sustainable territorial planning. However, such ecosystems are vulnerable to the disruption caused by several anthropogenic sources. Among other global threat factors, the inevitable sea rise caused by climate change and, at a local scale, the non-negligible implications of trampling caused by disorderly coastal touristic exploitation, growing construction pressure in the littoral, and a seasonal population boom in late spring and in summer, plus all derivate forms of pollution, are threat factors to their integrity. Therefore, a correct planning of the touristic economic activities requires the understanding of the vegetation composition and spatial distribution patterns, intrinsically determined by their biogeographic context in the Euro-Siberian or Mediterranean Regions. This comprehensive work, based on a broad phytogeographic study, brings together disperse information on plant communities of the Portuguese sandy coasts (beaches and dunes), by analysing floristic compositions, chorology and ecological characteristics, and matching them with the “Nature 2000” network habitats. Resilience and vulnerability are also studied. In a nature conservation perspective, a positive balance (and a sustainable co-existence) between the preservation of natural values and human development in the Portuguese coast, will benefit with the integration of this knowledge in coastal planning and management activities.     

乡土植物在广梧高速公路生态绿化中的应用

绿化关系到高速公路的长期效益,是生态高速公路建设的重要内容。广梧高速公路的生态绿化,以利用乡土植物为原则,模拟自然生态系统的组成和结构,实现公路景观与周边自然景观的和谐统一。对广梧高速公路双凤至平台段的自然条件、植被类型及植物种类进行了全面调查,结果显示该地域共有维管束植物342种,隶属于95科244属,然后结合植物本身的生物学、生态学及生理学特征,从中筛选出适于本段高速公路两侧绿化带、边坡绿化的乡土植物53种;并根据沿线具体的生境条件,按照群落学的原则对其组合应用进行了设计。     

Natural resource depletion and the economic performance of local districts: suggestions from a within-country analysis

SUMMARY

Studying the interactions among ecological factors and economic performance measured at the local scale is necessary to suggest policies able to mitigate natural resource depletion in complex ecosystems, like those in the Mediterranean region. The aim of this paper is to explore the relationship among natural resource depletion due to land degradation (LD) and some economic characteristics of local labour systems in Italy, a country where many areas, especially southern regions, are vulnerable. LD was estimated using an environmental sensitive area index, covering the national territory at a fine scale, which takes into account ecological factors such as climate, soil and vegetation. Economic indicators used here consider per capita income, land productivity, production and labour productivity by sector (agriculture, industry and services). A regression analysis was built-up at the LLS scale using an index change over time (1990–2000) as dependent variable and economic variables as predictors. A principal component analysis (PCA) was carried out to synthesise the outputs of the regression analysis. Results indicate a negative relationship among per capita income and LD over the whole study area. However, other variables showed a significant correlation with the dependent variable, highlighting the importance of local factors to increase land vulnerability. In order to clarify the contribution of economic factors to natural resource depletion it is necessary to drive integrate policies to combat LD in dry Mediterranean areas.     

深圳市盐田区植被格局分析

运用景观生态学的方法 ,选取斑块形状指数、斑块形状破碎化指数、分维数、景观多样性指数、均匀度、相对丰富度、优势度等指标 ,对深圳盐田区的植被格局进行分析。结果显示 :在城乡发展过程中 ,盐田区植被景观保存较好 ,类型丰富 ;植被景观总体上呈现出符合其生境特征的规则分布 ;群落景观异质性较高 ,拥有南亚热带的沟谷雨林、山地常绿阔叶林、红树林等特色植被景观 ;沟谷雨林和季风常绿林是本区较脆弱的生态系统 ,应积极加以保护和发展     

Afghanistan: Environmental degradation in a fragile ecological setting

SUMMARY

Currently, only 6% of the 15% of land in Afghanistan is usable and, if all the refugees were to return, problems of land ownership and adequacy of available land are inevitable. Natural forests have been severely degraded. Due to the nature of the topography and the arid climate, vast areas are subject to soil erosion. Loss of vegetation and soil humus have created ever more arid conditions. Abandoning the lands, poor reclamation schemes, overgrazing and destruction of vegetation for fuelwood have all caused desertifkation. The biological productivity of pastures has also deteriorated. This reduced productivity has affected livestock and has caused dramatic changes to the patterns of wildlife populations. Soil salinization and waterlogged lands are common. Farmland and pastures have been contaminated by landmines. Heavy concentrations of air-borne particulates and considerable amounts of transboundary pollutants from the Aral Sea have been found. Use of chemicals and the machinery of war have damaged the ecosystems.

Collection of plants and animals is unregulated and has resulted in excessive removal or extermination of some species endemic to the Hindu Kush. Uprooting of some plants and dynamite fishing are increasing and a disturbing number of fauna and flora are endangered. Agriculture is traditional, and natural resources are not being used in a sustainable way. A sound environmental strategy needs to be formulated and adopted.     

The role of spatial scale in sustainable development

The role of spatial scale in sustainable development is assessed by dividing the world into multiple spatial units at different levels on a socio-political spatial scale. The basic patterns of sustainable development do not appear to be evident at all spatial levels, owing to the absence of some capital stocks and the conversion processes linking them, but environmental economics theory can be generalized to explain phenomena at various levels. Capital conversion processes influencing the sustainability of development of spatial units are constrained by processes at different levels, e.g. those imposing environmental conditions on development or affecting availability of investment capital. The autonomy of individual spatial units is also compromised by capital transfers to and from other units at the same level, so it is proposed that the sustainability of development of a particular unit should be estimated using net, rather than gross capital trends. Because of uneven development the same degree of sustainability should not be expected at the same time for all spatial units at the same spatial level.     

Rehabilitating China's Largest Inland River

Abstract:  Wetlands are particularly important for conserving China's biodiversity but riparian wetlands in the Tarim River basin in western China have been reduced by 46% during the last 3 decades. The world's largest habitat for Populus euphratica , which is in the Tarim River basin, significantly shrank. To protect and restore the deteriorated ecosystems along the Tarim River and its associated wetlands, China's government initiated a multimillion dollar river restoration project to release water from upper dams to the dried-up lower reaches of the Tarim River starting in 2000. We monitored the responses of groundwater and vegetation to water recharge in the lower reaches of the river from 2000 to 2006 by establishing nine 1000-m-long transects perpendicular to the river at intervals of 20–45 km along the 320-km river course below the Daxihaizi Reservoir, the source of water conveyance, to Lake Taitema, the terminus of the Tarim River. Water recharges from the Daxihaizi Reservoir to the lower reaches of the Tarim River significantly increased groundwater levels and vegetation coverage at all monitoring sites along the river. The mean canopy size of the endangered plant species P. euphratica doubled after 6 years of water recharge. Some rare migrating birds returned to rest on the restored wetlands in summer along the lower reaches of the Tarim River. The biggest challenge facing decision makers, however, is to balance water allocation and water rights between agricultural and natural ecosystems in a sustainable way. A large number of inhabitants in the Tarim Basin depend on these limited water resources for a living. At the same time, the endangered ecosystems need to be protected. Given the ecological, socioeconomic, and sociopolitical realities in the Tarim Basin, adaptive water policies and strategies are needed for water allocation in these areas of limited water resources.     

Ecological Trap for Desert Lizards Caused by Anthropogenic Changes in Habitat Structure that Favor Predator Activity

Abstract: Anthropogenic habitat perturbation is a major cause of population decline. A standard practice managers use to protect populations is to leave portions of natural habitat intact. We describe a case study in which, despite the use of this practice, the critically endangered lizard Acanthodactylus beershebensis was locally extirpated from both manipulated and natural patches within a mosaic landscape of an afforestation project. We hypothesized that increased structural complexity in planted patches favors avian predator activity and makes these patches less suitable for lizards due to a heightened risk of predation. Spatial rarity of natural perches (e.g., trees) in arid scrublands may hinder the ability of desert lizards to associate perches with low‐quality habitat, turning planted patches into ecological traps for such species. We erected artificial trees in a structurally simple arid habitat (similar to the way trees were planted in the afforestation project) and compared lizard population dynamics in plots with these structures and without. Survival of lizards in the plots with artificial trees was lower than survival in plots without artificial trees. Hatchlings dispersed into plots with artificial trees in a manner that indicated they perceived the quality of these plots as similar to the surrounding, unmanipulated landscape. Our results showed that local anthropogenic changes in habitat structure that seem relatively harmless may have a considerable negative effect beyond the immediate area of the perturbation because the disturbed habitat may become an ecological trap.     

Vegetation dynamics on the Łeba Bar/Poland: a comparison of the vegetation in 1932 and 2006 with special regard to endangered habitats

Coastal dune ecosystems are among the most dynamic habitats with high conservation value in Europe but are also under strong anthropogenic pressure regarding coastal protection and recreation. Hence, it is of high importance to know about long-term natural and anthropogenic changes and development of protected dune habitats for nature conservation, as well as for coastal management. This paper aims to identify the vegetation dynamics on the Łeba Bar/Poland over a period of 74 years by cartometric comparison using modern Geographical Information System (GIS). To quantify the rate of vegetation dynamics two aerial photographs dating from 1932 and 2006 were digitalized and analyzed with GIS to produce digital vegetation maps. Information about decrease, increase and stability of vegetation types of this area are discussed. The results show that there has been a clear reduction in the total area of bare sand and a considerable increase of woodlands and dense grass communities. Nevertheless, the remaining extensive drift sand areas and deflation hollows on the Łeba Bar offer one of the most important habitats for pioneer vegetation on bare sand of migrating dunes and dunes at the Southern Baltic coast. The present work proved the need to observe the future development of the vegetation communities and to implement management measures to maintain the dynamic of this unique dune landscape.     

A Conservation Gap Analysis of Brazil''s Amazonian Vegetation

Vegetation types lacking protection in the existing conservation units of the nine states in the Brazilian Legal Amazon were identified, and locations were noted where these vegetation types could be protected. Maps of vegetation, protected areas, and semi-protected areas, such as Amerindian and forestry reserves, were digitized and overlaid using a geographic information system. There are 28 natural vegetation types in the Brazilian Legal Amazon. Locations of new areas for protection were selected using a minimum criterion of protecting at least one example of each vegetation type in each state (here called "vegetation zones"). There are 111 vegetation zones in the Legal Amazon, of which only 37 (33%) have some portion of their area protected. There are few protected areas in the most heavily deforested states along the southeastern fringe of the forest. In Maranhão, where 60% of the original forest had been lost by 1990, only one of 10 vegetation types is protected. Negotiating agreements with indigenous tribes, and to a lesser extent with extractivists who harvest nontimber products from the forest, represents a major opportunity to increase significantly the area and representativeness of the conservation units. Additional conservation units need to be established quickly before rapidly increasing deforestation and land prices preclude this opportunity; otherwise, some vegetation types may virtually disappear.     

Multistate modeling of habitat dynamics: factors affecting Florida scrub transition probabilities

Many ecosystems are influenced by disturbances that create specific successional states and habitat structures that species need to persist. Estimating transition probabilities between habitat states and modeling the factors that influence such transitions have many applications for investigating and managing disturbance-prone ecosystems. We identify the correspondence between multistate capture-recapture models and Markov models of habitat dynamics. We exploit this correspondence by fitting and comparing competing models of different ecological covariates affecting habitat transition probabilities in Florida scrub and flatwoods, a habitat important to many unique plants and animals. We subdivided a large scrub and flatwoods ecosystem along central Florida's Atlantic coast into 10-ha grid cells, which approximated average territory size of the threatened Florida Scrub-Jay (Aphelocoma coerulescens), a management indicator species. We used 1.0-m resolution aerial imagery for 1994, 1999, and 2004 to classify grid cells into four habitat quality states that were directly related to Florida Scrub-Jay source-sink dynamics and management decision making. Results showed that static site features related to fire propagation (vegetation type, edges) and temporally varying disturbances (fires, mechanical cutting) best explained transition probabilities. Results indicated that much of the scrub and flatwoods ecosystem was resistant to moving from a degraded state to a desired state without mechanical cutting, an expensive restoration tool. We used habitat models parameterized with the estimated transition probabilities to investigate the consequences of alternative management scenarios on future habitat dynamics. We recommend this multistate modeling approach as being broadly applicable for studying ecosystem, land cover, or habitat dynamics. The approach provides maximum-likelihood estimates of transition parameters, including precision measures, and can be used to assess evidence among competing ecological models that describe system dynamics.     

Ecological processes and sustainability

SUMMARY

Ecology has developed from its position as an obscure science to being at the interface of science and public policy. The impact of mankind can be described in ecological terms relating to population size, energy use and non-renewability. Sustainable development needs to be addressed on the basis of knowledge of ecological processes which maintain the environment in a state of change; the processes need to be conserved, not maintained in any particular state. Recent advances in the understanding of ecological processes are reviewed to highlight the potential contribution of this knowledge to the development of a sustainable policy. At the level of the population the significance of considering the extinction risks in the framework of spatio-temporal dynamics is now established indicating opportunities for planning land use more precisely to sustain biodiversity. Whilst the maintenance of habitats is generally the key to the persistence of biodiversity, they must be viewed as ever-changing mosaics within which cycles of succession, best described by Markovian sets of probabilities, are occurring continually. The extent to which these probabilities are distorted will determine whether the ecosystem returns to the same system or moves to a novel one. At the global level, biogeochemical cycles have a certain flexibility in relation to fluxes and stocks, hence pollution must be defined by relating the flow rate of the substance to this flexibility, which often permits the accommodation of anthropogenic perturbations. Non-sustainable processes can be defined in ecological terms, thus providing functional definitions of a sustainable policy and of sustainable development.     

Managing Invasive Aquatic Plants in a Changing System: Strategic Consideration of Ecosystem Services

Abstract:  Climate change is projected to increase stress for many coastal plant communities. Along large portions of the North American coast, habitat degradation from anthropogenic changes to the environment already threaten the community structure of tidal marshes and submerged aquatic grass beds. The potential loss of ecological services historically provided by these communities has been a long-standing rationale for aggressive control of invading plants such as Phragmites australis and Hydrilla verticillata . Increasing evidence of ecological services provided by invasive species such as P. australis and H. verticillata suggest that, in the face of increasing stress, it may be prudent to take a more pragmatic approach regarding the effect of these species on coastal ecosystems. The notable resilience of these species to control efforts and their competitive success and comparative vigor in stressed systems and capacity to provide at least some beneficial services combine to suggest some invasive species may have a useful role in managed coastal ecosystems.