Agent-based land-use models: a review of applications

Agent-based modelling is an approach that has been receiving attention by the land use modelling community in recent years, mainly because it offers a way of incorporating the influence of human decision-making on land use in a mechanistic, formal, and spatially explicit way, taking into account social interaction, adaptation, and decision-making at different levels. Specific advantages of agent-based models include their ability to model individual decision-making entities and their interactions, to incorporate social processes and non-monetary influences on decision-making, and to dynamically link social and environmental processes. A number of such models are now beginning to appear—it is timely, therefore, to review the uses to which agent-based land use models have been put so far, and to discuss some of the relevant lessons learnt, also drawing on those from other areas of simulation modelling, in relation to future applications. In this paper, we review applications of agent-based land use models under the headings of (a) policy analysis and planning, (b) participatory modelling, (c) explaining spatial patterns of land use or settlement, (d) testing social science concepts and (e) explaining land use functions. The greatest use of such models so far has been by the research community as tools for organising knowledge from empirical studies, and for exploring theoretical aspects of particular systems. However, there is a need to demonstrate that such models are able to solve problems in the real world better than traditional modelling approaches. It is concluded that in terms of decision support, agent-based land-use models are probably more useful as research tools to develop an underlying knowledge base which can then be developed together with end-users into simple rules-of-thumb, rather than as operational decision support tools. This paper arises from research conducted as part of the UK Research Councils’ RELU Programme (award number RES-224-25-0102). RELU is funded jointly by the Economic and Social Research Council, the Biotechnology and Biological Sciences Research Council and the Natural Environment Research Council, with additional funding from the Department for Environment, Food and Rural Affairs and the Scottish Executive Environment and Rural Affairs Department.     

A Markov model of land-use change dynamics in the Niagara Region,Ontario, Canada

Regional Niagara is the site of an intense three-way land-use conflict among urban, agricultural and natural uses. Large scale spatial and temporal land-use data were used to investigate the dynamics of land-use change in this area. A first order Markov chain was used as a stochastic model to make quantitative comparisons of the land-use changes between discrete time periods extending from 1935 to 1981. The Markov model allowed for two main conclusions about the historic dynamics of land-use change in the Regional Municipality of Niagara.

1. The urbanization of agricultural land was the predominant land-use change.
2. A continuing ‘exchange’ of land area occurs between wooded and agricultural land-use categories that has little effect on the net amount of wooded land but which could undermine the long-term ecological value of remaining natural areas in Niagara.

     

DNA chip and its applications in medicine

The development of DNA chip has been strongly driven by modern approaches of life science and microelectronics. The broad of DNA chip applications include the detection of pathogens, the detection of mutations in genes involved in human diseases or affected during cancer progression, sequence analysis, the pattern of gene expression monitoring and pharmacy studies. This review explains the technology, its scope, and impact on medicine, as well as its cost and possible limitations.     

The importance of land-use legacies for modeling present-day species distributions

Context

Land-use legacies play an important role in shaping contemporary species distributions. However, land-use legacies are rarely considered in species distribution models (SDMs) that aim to model present-day species distributions across the landscape, even though they can lead to a species absence in suitable areas. SDMs that do not account for land-use legacies will likely result in biased predictions of species distributions.

Objective

We examine the importance of land-use legacies for modeling present-day distributions of tree species at a regional scale, assessing how the addition of land-use legacy variables improves predictive power of SDMs.

Methods

We generated land-use legacy variables using raster layers of reconstructed historical agricultural land use and 3310 inventory plots. SDMs were developed for six forest tree species based on climatic, edaphic, and topographic variables, and with (SDM_LU) and without (SDM_Base) land-use legacy variables. We compared the predictive power between SDM_LU and SDM_Base models and then quantified the local importance of land-use legacy variables relative to other abiotic variables.

Results

Our results show that the importance of land-use legacy variables for present-day species distributions and the improvement on the predictive power of SDMs is species-specific. The inclusion of land-use legacy variables improved SDMs primarily by lowering errors of commission and increasing the overall accuracy of prediction.

Conclusion

The influence of land-use legacies on SDMs suggests that, for some tree species, incorporating land-use legacies can accurately identify suitable areas that are not occupied by the species due to land-use legacies, and advance our understanding of their present-day distributions.

     

Forecasting the spatial dynamics of gypsy moth outbreaks using cellular transition models

A series of cellular transition probability models that predict the spatial dynamics of gypsy moth (Lymantria dispar L.) defoliation were developed. The models consisted of four classes: Simple Markov chains, Rook's and Queen's move neighborhood models, and distance weighted neighborhood models. Historical maps of gypsy moth defoliation across Massachusetts from 1961 to 1991 were digitized into a binary raster matrix and used to estimate transition probabilities. Results indicated that the distance weighted neighborhood model performed better then the other neighborhood models and the simple Markov chain. Incorporation of interpolated counts of overwintering egg mass counts taken throughout the state and incorporation of historical defoliation frequencies increased the performance of the transition models.     

Incorporating biological information in local land-use decision making: designing a system for conservation planning

Human settlement is a formidable agent of change affecting fundamental ecological processes. Decisions governing these land-use changes occur almost exclusively at the local level and, as a result, they are made at many different locations and times. Consequently, it is difficult for ecologists to provide needed scientific support for these choices. We built an information system designed to support conservation decisions at local scales by offering data over the Internet. We collaborated with local stakeholders (e.g., developers, planners, politicians, land owners, environmental activists) to design the system. This collaboration produced several generalizations about effective design of information systems to support conservation. The most important of these is the idea that ecological data and analysis must be understood by those who will be affected by the decisions. Also, planning for conservation is a process that uses scientific data, but that ultimately depends on the expression of human values. A major challenge landscape ecologists face is to extend general landscape principles to provide specific scientific information needed for local land-use planning.     

柑橘果胶的生物学功能及其在生物医学中的应用

柑橘果胶是存在于柑橘果皮中一种结构复杂的异质型多糖,具有抗氧化、抗炎、抗癌、降血脂、吸附重金属、运输药物/细胞等重要的生物功能。柑橘果胶具有优良的生物降解能力、生物相容性、安全无毒和成本低等特点,因此在食品和生物医学领域备受关注。近年来,基于柑橘果胶的生物材料在结肠靶向药物输送及其他生物医学领域的应用已成为新的研究热点,笔者在对柑橘果胶重要的生物功能进行总结的基础上,进一步阐述了基于柑橘果胶的生物材料在生物医学方面的应用进展,包括应用形式和柑橘果胶在材料中的重要作用。最后,介绍了柑橘果胶研究与利用新进展,希望为我国柑橘果胶资源的科学利用提供新信息。     

In vitro micrografting and its applications to fruit science

Improvements have been brought to in vitro micrografting. The breaking of dormancy by dipping the seeds of the rootstock in concentrated solutions of benzylaminopurine avoids having recourse to long stratification in the cold (60–120 days according to species). The initial pre-treatment of apices with cytokinin allows their development and facilitates later grafting. Moreover, adding DIECA to the cut sections avoids oxidation and, together with the insertion of a piece of agar between apex and rootstock, increases the success of micrografting. Finally, a special technique of in vivo micrografting of pretreated apices on young plants has been developed.Micrografting is commonly used to obtain peach trees free of Sharka and NRS viruses, and to study incompatibility mechanisms in heterografts, leading to an early diagnosis of incompatibilities.     

Heparanase - a novel regulator for cell and matrix interactions

Dynamic interactions between cells and underlying extracellular matrices are crucial for development, maintenance of cellular function, and response of tissure to injury and infection. Heparan sulfate proteoglycans (HSPG) are found in extracelular matrices and on the surface of most nuclrarated cells,and play critical roles in cell-cell and cell-matrix signal transduct ion by binding many molecules, such as growth factors and cytokines. Most of the biological properties of HSPG are conferred by heparan sulfate side chains, which can be degraded by heparanase. Changes of heparanase expression and activity may affect the biological processes above, which enables extravasation of inflammation cells, metastasis and neoangiogenesis of tumor cells invasion.     

The influences of land-use changes on hydrology and riparian environment in a northern Japanese landscape

Temporal changes in a hydrological system and riparian ecosystem were examined with reference to land-use conversion in order to clarify the linkages between these two systems. First, the hydrological system of the Toikanbetsu River basin was divided into three components that measure water retention, inundation and conveyance. Variation in the hydrological system was expressed as a basis of delineating the three components and estimating their functions. The rainfall-runoff system was also examined using a model which can predict responses of surface-, subsurface- and base flows on rainfall intensity. Second, areas and fragmentation of the riparian forests, maximum stream temperature in summer and amount of coarse woody debris (CWD) were selected as parameters indicating the condition of the riparian ecosystem. Temporal changes in stream temperature and amount of CWD were estimated using multiple regression analysis and analysis of variance, respectively. The results indicated that the hydrological system has been altered since the 1970s, increasing flood peaks by 1.5–2.5 times and shortening peak appearance by 7 hours. Riparian forests have been disappearing since the 1960s due to extensive development of agricultural lands and river channelization. The summer maximum stream temperature increased from 22 °C in 1947 to 28 °C at present. The amount of CWD should substantially decrease with river channelization and associated forest cutting. Fish favoring cool water, such as masu salmon, could survive in 1947 although they are forced to migrate to cooler forested upstream tributaries now. The ecological systems were closely related to and distinctly altered by land-use. Finally, we propose a new perspective for understanding the two interrelated systems. Riparian ecosystems can be restored by restoring water retention and inundation functions, which also reduce the flood hazard generated by elevated flood peaks.     

空间诱变育种及其在瓜类上的应用

空间诱变育种(或航天育种)是航天技术与现代生物技术、常规育种技术相结合的新育种技术。论述了空间诱变育种的概念、方法、机理、特点及国内外研究概况,并分析了空间诱变育种技术在瓜类育种上的应用,对其前景进行了展望。     

Spatial relationship between biodiversity and geodiversity across a gradient of land-use intensity in high-latitude landscapes

Context

‘Conserving Nature’s stage’ has been advanced as an important conservation principle because of known links between biodiversity and abiotic environmental diversity, especially in sensitive high-latitude environments and at the landscape scale. However these links have not been examined across gradients of human impact on the landscape.

Objectives

To (1) analyze the relationships between land-use intensity and both landscape-scale biodiversity and geodiversity, and (2) assess the contributions of geodiversity, climate and spatial variables to explaining vascular plant species richness in landscapes of low, moderate and high human impact.

Methods

We used generalized additive models (GAMs) to analyze relationships between land-use intensity and both geodiversity (geological, geomorphological and hydrological richness) and plant species richness in 6191 1-km² grid squares across Finland. We used linear regression-based variation partitioning (VP) to assess contributions of climate, geodiversity and spatial variable groups to accounting for spatial variation in species richness.

Results

In GAMs, geodiversity correlated negatively, and plant species richness positively, with land-use intensity. Both relationships were non-linear. In VP, geodiversity best accounted for species richness in areas of moderate to high human impact. These overall contributions were mainly due to variation explained jointly with climate, which dominated the models. Independent geodiversity contributions were highest in pristine environments, but low throughout.

Conclusions

Human action increases biodiversity but may reduce geodiversity, at landscape scale in high-latitude environments. Better understanding of the connections between biodiversity and abiotic environment along changing land-use gradients is essential in developing sustainable measures to conserve biodiversity under global change.

     

SSR分子标记及其在植物遗传育种中的应用

分子标记技术是基于生物体基因组的遗传分析方法,在植物的亲缘关系分析、遗传多样性分析、遗传图谱构建、分子辅助育种、品种鉴定等研究中已有广泛应用。其中微卫星分子标记(Simple sequence repeats,SSRs)技术作为一种新世纪遗传学研究工具,以其信息量大,重复性好、可靠性高和多态性丰富等优点,在植物遗传育种研究中表现出很大的优势。本文简要介绍了简单重复序列(SSRs)标记的分布、功能、技术优缺点和产生多态性的机理,并对SSR标记在植物遗传多样性、遗传图谱构建、基因定位与克隆、分子标记辅助育种等研究中的应用情况进行了综述,为植物资源利用、开发和保护等研究领域的应用提供参考。     

Native-exotic richness relationships in second-growth forests differ along a gradient of land-use history

Landscape Ecology - The relationship between native and non-native species richness is influenced by drivers including disturbance history and environmental character. Disturbance influences...     

TP-M13-SSR技术在梨遗传多样性研究中的应用

利用在SSR扩增产物检测过程中的一种基于荧光测序技术的高通量低成本分析技术体系TP-M13-SSR (simple sequence repeat with tailed primer M13)对5个种25份梨种质资源材料进行了SSR标记的遗传多样性研究.利用NH013a和NH007b2对引物即可区分所有供试品种,5对...     

Propagule pressure and land-use are more important than climate for invasive bryophytes regional distributions

Landscape Ecology - The spread of invasive bryophytes in Central Europe started in the 2nd half of the twentieth century. However, still it is not known which climatic and land-use factors shape...     

Global analysis and simulation of land-use change associated with urbanization

A combination of rapid population growth and an accelerating demographic shift from rural to urbanized habitats has resulted in urbanization becoming an increasingly global phenomenon. Two alternate hypotheses describing urban landscape trajectories suggest urbanization is either leading to more homogeneous global patterns or urbanization has dichotomous trajectories of increasing dispersal or coalescence. To better understand the global variation in urban land-cover patterns and trajectories we described the variation in urban landscape structure for 120 cities distributed throughout the world assessed at circa 1990 and 2000. We coupled these data to a low-dimensional neighborhood based model of urban growth using a data-model fusion approach. Trajectories of urban growth were assessed using both the original data and model projections to 2030. The patterns of landscape change were related to both the rate of growth and income. The historical patterns of change showed a trend of increasing landscape complexity and this trend was projected to continue. Urban rate of growth was closely related to the change in several landscape metrics. Income was associated with landscape dynamics and this effect interacted with city size. Large cities were less sensitive to the income effect than small cities. Along with changes to the magnitude of each metric, the overall variation in metrics between years generally exhibited a decrease in variability and this variability was projected to continue decreasing. These findings supported the hypothesis that urban landscapes are becoming more homogeneous and that the dispersal-coalescing dichotomy represent endpoints rather than alternate states of urban growth.     

Changes in land-use/land-cover patterns in Italy and their implications for biodiversity conservation

Land-use/land-cover change is the most important factor in causing biodiversity loss. The Mediterranean region has been affected by antropic disturbance for thousands of years, and is, nowadays, one of the most significantly altered hotspots in the world. However, in the last years a significant increase in forest cover has been measured. These new patterns are independent from planned conservation strategies and appear to have a substantial impact on landscapes and biodiversity. We used three land-use/land-cover maps (from 1960 to 2000) covering the Italian peninsula to analyze the pattern of land-use/land-cover change. We measured an increase in forests, especially in mountains, an increase in artificial areas, especially in coastal zones, and a decrease in pastures. Intensively cultivated areas showed a limited decrease while extensively cultivated ones showed a marked decrease. In the same period mammal and bird species followed a similar pattern, with forest birds, ungulates and carnivores increasing, and typically Mediterranean species decreasing. We suggest that our results may provide important information, which could be useful for conservation planning in the entire Mediterranean hotspot. We suggest that an increasing conservation effort should be made to protect the Mediterranean-type forests and scrublands, as well as traditional agricultural practices. Moreover, future conservation efforts should consider the broad socio-political and ecological processes that are most likely to occur across the whole hotspot, especially along coastal areas, and the network of protected areas should be functionally integrated in a conservation strategy that includes the human-dominated landscape.     

Effect of salvianolic acid B on high glucose-induced phenotypic transition and extracellular matrix secretion in human glomerular mesangial cells

AIM:To investigate the effect of salvianolic acid B (Sal B) on high glucose-induced phenotypic transition and extracellular matrix (ECM) secretion in human glomerular mesangial cells (HGMCs) and the underlying mechanisms. METHODS:HGMCs were randomly divided into control group, high glucose group and high glucose plus high dose, medium dose and low dose of Sal B groups. The HGMCs except those in control group were exposed to high glucose (33.3 mmol/L) for 72 h, while those in Sal B groups were co-incubated with indicated concentrations of Sal B. The protein levels of α-smooth muscle actin (α-SMA), transforming growth factor-β₁ (TGF-β₁) and phosphorylated Smad2 and p38 mitogen-activated protein kinase (MAPK) were determined by Western blot. The secretion levels of collagen type I (Col I), collagen type Ⅲ (Col Ⅲ), fibronectin (FN) and laminin (LN) were measured by ELISA. RESULTS:Exposure to high glucose markedly increased the protein expression of α-SMA, TGF-β₁, Col I, Col Ⅲ, FN and LN in the HGMCs (P<0.01). The phosphorylation levels of Smad2 and p38 MAPK were also significantly increased (P<0.01). Co-incubation with Sal B evidently decreased the protein expression of α-SMA, TGF-β₁, Col I, Col Ⅲ, FN and LN in the HGMCs induced by high glucose (P<0.05 or P<0.01). The phosphorylated levels of Smad2 and p38 MAPK were also reduced noticeably (P<0.05 or P<0.01). CONCLUSION:Sal B significantly suppresses high glucose-induced phenotypic transition and ECM secretion in the HGMCs, which might be attributed, at least partly, to inhibition of TGF-β₁/Smad signaling pathway and p38 MAPK activation.