Rangeland Degradation Impacts on Vegetation Cover, Soil Properties and Ecosystem Functioning in an Arid and Semi-Arid Climate, South Africa

The negative effect of soil erosion and soil compaction is well documented for the purpose of optimum rangeland functioning, while the impact of rangeland degradation on effective soil depth is seldom quantified. The aim of this study was to quantify the response of vegetation cover and soil properties, particularly effective soil depth and soil texture to rangeland degradation. Forty-one farms were sampled in the arid and semi-arid climate of South Africa. Within these farms, data was collected over a vegetation degradation gradient. Results showed a significant decline in relative basal cover (94% ± 15% to 39% ± 17%) and soil depth (90% ± 14% to 73% ± 24%) as rangeland degraded. Soil texture changes over the degradation gradients vary for different homogeneous vegetation types. Indications regarding the loss of a functioning rangeland ecosystem were also demonstrated, using objective long-term relations between rangeland conditions and grazing capacity. The study highlights the importance of sustainable rangeland management practices to reduce the loss in effective soil depth and to ensure the sustainable utilization of the rangeland ecosystem. These results can probably extrapolate to other arid and semi-arid rangelands worldwide.

Critical role of multidimensional biodiversity in contributing to ecosystem sustainability under global change

The 21st century has seen an acceleration of global change,including climate change,elevated carbon dioxide,nitrogen deposition,and land-use intensification,which poses a significant threat to ecosystem functioning.Nev-ertheless,studies on the relationship between biodiversity and ecosystem functioning(BEF)have consistently demonstrated that biodiversity enhances ecosystem functioning and its stability,even in variable environmental conditions.These findings potentially indicate the critical role of biodiversity in promoting sustainable provi-sioning of ecosystem functioning under global change.Our paper provides a comprehensive review of current BEF research and the response of BEF to multiple global change factors.We demonstrate that(1)assessing the effects of biodiversity on ecosystem functioning requires consideration of multiple dimensions of diversity,such as diversity across multiple trophic levels(plants,animals,and microbes),multiple facets(taxonomy,functional traits,and phylogeny),and multiple spatial scales(local,regional,and landscape scales).(2)The interaction of multiple global change factors may lead to a greater reduction in biodiversity and ecosystem functioning than a single global change factor.(3)Multidimensional biodiversity regulates the response of ecosystem functioning to global change factors,indicating that high levels of multidimensional biodiversity can mitigate the negative impacts of global change on ecosystem functioning.Overall,we emphasize that recognizing the importance of multidimensional biodiversity is critical for sustaining ecosystem functioning.Therefore,prioritizing conserva-tion efforts to maintain and enhance all dimensions of biodiversity is essential to address the challenges of future global change.

Changes in Ecosystem Service Values on the Loess Plateau in Northern Shaanxi Province,China

The Loess Plateau in northern Shaanxi Province of China covers Yulin, Yan＇an, and Tongchuan cities mainly. The kind of physiognomy is complicated and various, including the transitional region of the sand and wind, the hilly-gully fragile region, the pimple mound region from North to South. Large-scale land reclamation projects that are severely affecting these ecosystems have been implemented. In this paper, we reported an investigation to the changes in land use and ecosystem services on the Loess Plateau in northern Shaanxi Province from 1978 to 2000. We used three LANDSAT TM and/or ETM data sets to estimate the changes in the size of five land-cover/land-use categories, and we also used previously published value coefficients to estimate the changes in the value of ecosystem services delivered by each land category. Finally, we ranked the contribution of various ecosystem functions to the overall value of the ecosystem services, we have estimated that the annual value of the ecosystem services is 56.95 billon RMB yuan in the Loess Plateau in northern Shaanxi Province in 2000. In the region, from 1978 to 2000, the economic value of the fixing carbon was higher, the economic value of water conservation was the lowest, but the economic value of the NPP, fixing carbon, and supplying oxygen accounted for above ninety percent of the total value, obviously the vegetation created the biggest ecosystem service value. We can conclude that future land-use policy formulation should give precedence to the conservation of these ecosystems over uncontrolled reclamation, and that further land reclamation should be based on rigorous environmental impact analyses.

Function of Rural Settlement Complex Ecosystem in Mountain Area:A Case Study of Raosi Village of Zuogong County,Tibet

Using energy analysis,the quantifying evaluation and study method on production, living and ecology functions and their sustainability of rural settlement ecosystem in mountain area is established with these energy index such as export of labor and products, export of water resource, internal energy reserve, energy consumption for human living, net energy of ecosystem function and net internal reserve. Taking rural settlement Raosi Village in Hengduan Mountains as a case study, and on the basis of the synthetic research into the ecological process of the complex ecosystem, the study shows that energy costs of production, human living and ecology functions are separately taking 1.36%, 13.59% and 85. 05% of the gross ecosystem functions, and the exertions of production and human living functions are close to a high-point state on the present using level of energy in the settlement. The study also shows that the most important function of a rural settlement in mountain area is its ecological rather productive function.

Value Assessment of Ecosystem Service Function of Ecological Public Welfare Forests in Wenchang City

Based on the measurement parameters and index in the Specifications for Assessment of Forest Ecosystem Services in China(LY/T 1721-2008),the value of ecological service functions of ecological public welfare forest in Wenchang City was evaluated and analyzed.The results show that the total value of ecosystem service function of ecological public welfare forests in Wenchang City is about 4.020 billion yuan,of which storage capacity,water purification,soil fixation,fertilizer(N,P and K fertilizer) conservation,carbon sequestration,oxygen release,forest nutrient accumulation,providing anion,absorbing SO_2,absorbing fluoride,absorbing NxO,absorbing soil heavy metals,dust retention,noise reduction,sterilization,forest protection,forest biodiversity protection,and forest recreation(ecological tourism) are about 1.510 billion,582.256 million,3.769 million,268.220 million,116.360 million,2.747 million,22.682 million,42.817 million,1.722 million,74,600,131,900,187.918 million,77.409 million,28.721 million,43.090 million,180.696 million,571.036 million,and 108.677 million yuan

The Impact of Ecosystem Functional Type Changes on the La Plata Basin Climate

In this paper, the effects of land cover changes on the climate of the La Plata Basin in southern South America are investigated using the Weather and Research Forecasting （WRF） Model configured on a 30/10- km two-way interactive nested grid. To assess the regional climate changes resulting from land surface changes, the standard land cover types are replaced by time-varying Ecosystem Functional Types （EFTs）, which is a newly devised land-cover classification that characterizes the spatial and interannual variability of surface vegetation dynamics. These variations indicate that natural and anthropogenic activities have caused changes in the surface physical parameters of the basin, such as albedo and roughness length, that contributed to regional climate changes. EFTs are obtained from functional attributes of vegetation computed from properties of the Normalized Difference Vegetation Index （NDVI） to represent patches of the land surface with homogeneous energy and gas exchanges with the atmosphere. Four simulations are conducted, each experimental period ranging from September to November in two contrasting years, 1988 and 1998. The influence of an identical EFT change on the surface heat fluxes, 2-m temperature and humidity, 10-m winds, convective instabilities and large-scale moisture fluxes and precipitation are explored for 1988 （a dry year） and 1998 （a wet year）. Results show that the surface and atmospheric climate has a larger response to the same EFT changes in a dry year for 2-m temperature and 10-m wind; the response is larger in a wet year for 2-m water vapor mixing ratio, convective available potential energy, vertically integrated moisture fluxes and surface precipitation. For EFTs with high productivity and a weak seasonal cycle, the near- surface temperature during the spring of 1988 and 1998 increased by as much as I^C in the central and western portions of La Plata Basin. Additionally, for higher productivity EFTs, precipitation differences were generally positive in both dry and wet years, although the patterns are not uniform and exhibit certain patchiness with drier conditions.

Effect of Implementing Ecosystem Functional Type Data in a Mesoscale Climate Model

In this paper, we introduce a new concept of land-surface state representation for southern South America, which is based on ＂functional＂ attributes of vegetation, and implement a new land-cover （Ecosystem Functional Type, hereafter EFT） dataset in the Weather and Research Forecasting （WRF） model. We found that the EFT data enabled us to deal with functional attributes of vegetation and time-variant features more easily than the default land-cover data in the WRF. In order to explore the usefulness of the EFT data in simulations of surface and atmospheric variables, numerical simulations of the WRF model, using both the US Geological Survey （USGS） and the EFT data, were conducted over the La Plata Basin in South America for the austral spring of 1998 and compared with observations. Results showed that the model simulations were sensitive to the lower boundary conditions and that the use of the EFT data improved the climate simulation of 2-m temperature and precipitation, implying the need for this type of information to be included in numerical climate models.

Identifying the priority areas for enhancing the ecosystem services in hilly and mountainous areas of southern China

Ecosystem services can be enhanced through ecological restoration,industrial structure adjustment,land-use optimization,and agricultural and forestry ecosystem transformation.The ecosystem services in hilly and mountainous areas of southern China are crucially needed to be enhanced since these regions are important ecological functional zones in China.However,due to its large area,it is not possible to simultaneously upgrade the ecosystem services for all areas,and therefore,priority areas need to be selected to individually upgrade the ecosystem service function.In this study,via an approach of combining remote sensing,geographic information system,and spatial statistics,we identify the priority areas that need to be upgraded based on the analysis of ecological sensitivity,importance of ecosystem service function,and decreased degree in ecosystem services.For five counties in hilly and mountainous areas of southern China,only less than 2% of the total area was identified as the first priority area;its land-use compositions were analyzed and recommendations on how to enhance ecosystem service were suggested.This approach overcomes the conflict and contradiction issues associated with identifying priority areas in previous studies and solves the problems of high cost or difficult implementation of priority areas.

Advances in research of function and valuation of ecosystem services

It is widely accepted that there is an economic progress beyond the Gross Domestic Product （GDP）, while global GDP has increased more than three-fold since 1950, whereas ecosystems have been largely occupied and depleted. Since the 1990s, emphasis has focused on function and valuation of ecosystem services, which is rarely treated as a market issue. This paper reviews recent developments on measures to evaluate and assess ecosystem services, while elucidating the function of ecosystem services. On the one hand, functions of ecosystem services are subdivided into several items such as gas reg- ulation, water regulation, soil and nutrient recycling. Also, there exist intellectually guided functions of ecosystem services, such as culture and recreation. On the other hand, ecosystems can be viewed as a supplier in the trade between human beings and natural resources such that all resources can be labeled and quantified.

Building a Database for the Future:Humans and Lakes within Ecosystems

1 Introduction Fresh or saline,lakes constantly exchange with other water bodies on the Earth.Together,they form a crucial part of the water cycle–one of the most important ecosystem functions supporting humans and other biological communities.Lakes have provided invaluable and irreplaceable ecosystem services(benefits)for the

Leaf nitrogen resorption is more important than litter nitrogen mineralization in mediating the diversity–productivity relationship along a nitrogen-limited temperate forest succession chronosequence

The resorption of nutrients by plants before litter fall and the mineralization of nutrients from plant litter by soil processes are both important pathways supporting primary productivity. While the positive relationship between plant biodiversity and primary productivity is widely accepted for natural ecosystems, the roles of nutrient resorption and mineralization in mediating that relationship remains largely unknown. Here, we quantified the relative importance of nitrogen(N) resorption and N mineralization in driving plant community N investment and the correlation between species diversity and community productivity along an N-limited successional chronosequence of the mixed broadleaved–Korean pine(Pinus koraiensis) forest in northeastern China. Leaf N resorption efficiency(NRE) at the community level increased significantly along the successional chronosequence,whereas litter N mineralization rate decreased significantly. Leaf NRE was more important than litter N mineralization rate in driving the diversity–productivity relationship. However, higher leaf NRE led to less N mineralization as succession progressed along the chronosequence. Our results highlight the importance of the N resorption pathway rather than the N mineralization pathway for forest N acquisition with community succession,and they provide mechanistic insights into the positive effects of biodiversity on ecosystem functioning. In future forest management practices, we recommend appropriate application of N fertilizer to mitigate the adverse effects of N-poor soil on seedling regeneration during late succession and thus maintain the sustainable development of temperate forest ecosystems.

A Preliminary Exploration of the Functional Value Assessment of Ecosystem Services in Aral City

Using the principles and methods of eco-economics as the research object,Aral City comprehensively expounds the ecological service functions such as ecosystem regulation of climate,carbon sequestration,soil conservation,water conservation and purification environment,and evaluates its economic value.The total value of the estimated 2021 is 1303.65 million yuan.At the same time,the importance of ecological service functions of urban ecosystems,from large to small,is to sequester carbon and release oxygen,purify the environment,maintain soil,conserd water sources,regulate the climate.The ecosystem service function which needs to be paid attention to in the concept of ecological construction and restoration of the next stage of ecological construction in Aral City.

Desertification risk,economic resilience and social issues:From theory to practice

Land degradation and early forms of desertification in both advanced economies and emerging countries reflect complex socio-environmental processes driven by multiple interactions between biophysical and socioeconomic forces across different spatial scales.The present study investigates desertification risk,land degradation,and socio-demographic dynamics through the lens of“resilience,”adopting complex adaptive systems(CAS)thinking.The resilience of socio-environmental systems exposed to land degradation is defined as the capacity of a regional economy to respond to crises and reorganize by making changes to preserve functions,structure,and feedback,and to promote future development options.By reviewing the socioeconomic resilience of local socio-ecological systems exposed to land degradation,this study achieves a better comprehension of the multifaceted processes that lead to a higher risk of desertification and the intimate relationship with underlying population trends and demographic dynamics.A comprehensive approach based on resilience thinking was formulated to review both environmental and socio-demographic issues at the landscape scale,and provide a suitable foundation for sustainability science and regional development policies.

Forest biodiversity, relationships to structural and functional attributes, and stability in New England forests

Background： Forest biodiversity is the foundation of many ecosystem services, and the effect of biodiversity on ecosystem functioning and processes （BEF） has been a central issue in biodiversity studies. Although many hypotheses have been developed to interpret global gradients of biodiversity, there has not been complete agreement on mechanisms controlling biodiversity patterns and distributions. Differences may be due to limited observation data and inconsistencies of spatial scales in analysis. Methods： In this study, we take advantage of USDA Forest Service forest inventory and analysis （FIA） data for exploring regional forest biodiversity and BEF in New England forests. The FIA data provide detailed information of sampled plots and trees for the region, including 6000 FIA plots and more than 33,000 individual trees. Biodiversity models were used to analyze the data. Results： Tree species diversity increases from the north to the south at a rate about 2-3 species per latitudinal degree. Tree species diversity is better predicted by tree height than forest age or biomass. Very different distribution patterns of two common maple species, sugar maple （Acer sdcchorum） and red maple （Acer rubrum）, highlight the vulnerability of sugar maple and its potential replacement by red maple on New England landscapes. Red maple generally already outperforms sugar maple, and will likely and continuously benefit from a changing climate in New England. Conclusions： We conclude that forest structure （height） and resources （biomass） are more likely foundational characteristics supporting biodiversity rather than biodiversity determining forest productivity and/or biomass. The potential replacement of red maple for sugar maple in the New England areas could affect biodiversity and stability of forest ecosystem functioning because sugar maple plays important ecological roles distinct from red maple that are beneficial to other tree species in northern hardwood forests. Such a change may not affect forest resilience in terms of forest productivity and biomass as these are similar in red maple and sugar maple, however, it would almost certainly alter forest structure across the landscape.

Tree diversity effects on forest productivity increase through time because of spatial partitioning

Background: Experimental manipulations of tree diversity have often found overyielding in mixed-species plantations. While most experiments are still in the early stages of stand development, the impacts of tree diversity are expected to accumulate over time. Here, I present findings from a 31-year-old tree diversity experiment(as of2018) in Japan.Results: I find that the net diversity effect on stand biomass increased linearly through time. The species mixture achieved 64% greater biomass than the average monoculture biomass 31 years after planting. The complementarity effect was positive and increased exponentially with time. The selection effect was negative and decreased exponentially with time. In the early stages(≤ 3 years), the positive complementarity effect was explained by enhanced growths of early-and mid-successional species in the mixture. Later on(≥ 15 years), it was explained by their increased survival rates owing to vertical spatial partitioning — i.e. alleviation of self-thinning via canopy stratification. The negative selection effect resulted from suppressed growths of late-successional species in the bottom layer.Conclusions: The experiment provides pioneering evidence that the positive impacts of diversity-driven spatial partitioning on forest biomass can accumulate over multiple decades. The results indicate that forest biomass production and carbon sequestration can be enhanced by multispecies afforestation strategies.

Can the Stepping Stone Enhance the Establishment, Competition and Distribution of Sown Grassland Species during Recovery on Ex-Arable Lands?

Most diversity restoration projects are not to improve diversity per se, but rather to enhance the presence and abundance of species that are characteristic of reference or target community. The use of Bromus inermis suppresses annual noxious grasses and increases the control of other-forb group these species are also noxious weeds;these may be substituted with another perennial species of the same functional group all through the whole experimental period, as it occurs with other perennial-forb Carduus tenuifolius. A field experiment was conducted on abandoned arable land with sown low and high diversity treatments and natural colonization following typical farming practice for the site. Experimental plots were installed on former agricultural land that had been cropped with (a rotation of) monocultures until the end of 1995. The experiment was organized according to a block design with five replicate blocks. An opposite trend was performed among the colonizer species, because the colonizer grasses were relegated by the high dominance of sown grasses. But at the same time, the sown grasses facilitated the dominance of other colonizer-forbs species;therefore its functional replacement in the community due to sown effect was again tested. However, in natural conditions the other-forbs group was the dominant group, without taking into account the stepping-stone treatment and there was also a functional change of dominance. Our study has demonstrated the restoration effectiveness of species richness at abandoned arable land and may be enhanced by sowing late successional species.

Perturbation Experiments in Community Plant Species during Recovery from Agricultural Abandonment in a Semi-Arid Region of Central-Western Spain

Background: Can high diversity mixtures of later succession plant species be able to suppress early successional (arable weed) species than low diversity species mixtures? Can the removal of plant functional groups have important consequences on the sys-tem stability? Location: The study area was located at 850 m a.s.l., fifteen kilometers (15 km) to the west of Salamanca city, Spain, in a dehesa-like woodland. Methods: The field experiment was installed in Spring 1996 (May). The plots represented former agricultural lands cropped with (a rotation of) monocultures and abandoned right at the beginning of the experiment after the last crop was harvested in 1995. Before in-stalling plots, the fields were harrowed and equalized. The treatments (NC-natural colonization, LD-low diversity seed mixture and HD-high diversity seed mixture) were randomly allocated to the plots in each block. The experiment was organised accord-ing to a block design with five replicate blocks. Within each block, four plots measur-ing 10 × 10 m were marked out and each of the three treatments was randomly as-signed to one plot. All plots were separated by 2 m walkways. Results: The competitive ability of the sown species in different mixtures in LD, valued on the basis of their performance in HD, is a good predictor of their ability to suppress the weed crops spe-cies. This was also corroborated by the high relationship between the efficiency of the sown species in both treatments of species mixture (R2 = 0.51, F (1, 33) = 34.56, P < 0.001). Conclusions: The increase of colonizing species cover was significantly lower in LD, which again supported the increase of biomass in 1998, being also lower in HD. Therefore, this increase in the community is more prominent in LD treatments. The effect of sown species was not so important in this increase.

Finding Food Security through Changing the Agricultural Model to Sustain Insect Biodiversity

Worldwide biodiversity is being threatened by human activities to a greater level wherein the natural ecosystems are reaching the verge of collapsing. We are faced with four major interrelated challenges namely a changing climate, biodiversity loss, human population growth and food production for this growing population. Agricultural intensification contributes significantly to biodiversity loss. The agricultural model for our current food production systems is mainly based on the Green Revolution, which promoted the cultivation of crops in extensive monoculture fields and intensified external inputs of agrochemicals. This model resulted in biodiversity loss, particularly in insect populations. A model based on ecological intensification as an alternative to agricultural intensification with minimized use of agro-inputs may slow the rate of biodiversity loss resulting in more sustainable agricultural ecosystems.

The emergence of global environmental awareness

An effective plan for global ecosystem management must be developed in the next 10 or 20 years. Awareness of the need has recently emerged, but still no integrated resource management system is universally accepted. A fragmented management approach has not been effective. Any successful course of action must be based on three assumptions: (1) that science can determine how ecosystems function, (2) once this is known, the social/political system will be able to protect ecosystems to the extent needed for the survival of human society, and (3) reality will take precedence over political expediency because Mother Nature cannot be fooled. This discussion focuses on the transition from awareness to taking effective action.

Linking Management and Riparian Physical Functions to Water Quality and Aquatic Habitat

Stream and wetland riparian areas are able to sustain a state of resiliency based on the ecosystem’s ability to attain the functions of its ecological potential. This resiliency allows an area to provide and produce desired and valued water quality and aquatic habitat ecosystem services. Maintaining healthy aquatic and riparian habitats depends on “management” allowing for, or facilitating natural recovery of riparian functions. Altering grazing management practices in Maggie Creek lead to changes in riparian functionality, water quality, and aquatic habitat. Maggie Creek basin, historically renowned for its fishery, is one of only a few watersheds in Nevada capable of supporting Lahontan Cutthroat Trout (LCT) (Oncorhynchus clarkia ssp. Henshawi) meta-populations. Prior to 1993, the majority of Maggie Creek was grazed by cattle throughout the growing season. Decades of intensive grazing, water development, and road construction degraded aquatic and riparian habitats. By the early 1990’s, a majority of the Maggie Creek watershed was rated as nonfunctional or functional-at-risk condition with unstable banks, channel incision, loss of riparian vegetation, wide shallow channels, excessive erosion and deposition, reduced stream flows, and increased water temperatures. As mitigation for their 1993 South Operations Area Project mine dewatering, Newmont Mining Company, in cooperation with the Elko District Bureau of Land Management (BLM) and the Elko Land and Livestock Company, developed the Maggie Creek Watershed Restoration Project to enhance LCT habitat. The project was developed to enhance 82 miles of stream, 2000 acres of riparian habitat and 40,000 acres of upland watershed primarily through prescriptive livestock management. Beginning in 1994, grazing systems were implemented for portions of the perennial/intermittent streams. This greatly reduced the frequency and duration of hot season grazing on Maggie Creek and its tributaries. The objective of this paper is to compare 1994 and 2006 stream and wetland riparian assessments using proper functioning condition (PFC) protocol and water quality data.