High value of short rotation coppice plantations for phytodiversity in rural landscapes

The demand for wood from short rotation coppice (SRC) plantations as a renewable energy source is currently increasing and could affect biodiversity in agricultural areas. The objective was to evaluate the contribution of SRC plantations to phytodiversity in agricultural landscapes assessed as species richness, species–area relationships, Shannon indices, detrended correspondence analysis on species composition, Sørensen similarities, habitat preference proportions, and species proportions found in only one land use. Vegetation surveys were conducted on 12 willow (Salix spp.) and three poplar (Populus spp.) coppice sites as well as on surrounding arable lands, grasslands and forests in central Sweden and northern Germany. SRC plantations were richer in plant species (mean: 30 species per 100 m²) than arable land (10), coniferous forests (13) and mixed forests in Germany (12). Comparing SRC plantations with other land uses, we found lowest similarities in species composition with arable lands, coniferous forests and German mixed forests and highest similarities with marginal grassland strips, grasslands and Swedish mixed forests. Similarity depended on the SRC tree cover: at increased tree cover, SRC plantations became less similar to grasslands but more similar to forests. The SRC plantations were composed of a mixture of grassland (33%), ruderal (24%) and woodland (15%) species. Species abundance in SRC plantations was more heterogeneous than in arable lands. We conclude that SRC plantations form novel habitats leading to different plant species composition compared to conventional land uses. Their landscape‐scale value for phytodiversity changes depending on harvest cycles and over time. As a structural landscape element, SRC plantations contribute positively to phytodiversity in rural areas, especially in land use mosaics where these plantations are admixed to other land uses with dissimilar plant species composition such as arable land, coniferous forest and, at the German sites, also mixed forest.     

The influence of time,soil characteristics,and land‐use history on soil phosphorus legacies: a global meta‐analysis

Agriculturally driven changes in soil phosphorus (P) are known to have persistent effects on local ecosystem structure and function, but regional patterns of soil P recovery following cessation of agriculture are less well understood. We synthesized data from 94 published studies to assess evidence of these land‐use legacies throughout the world by comparing soil labile and total P content in abandoned agricultural areas to that of reference ecosystems or sites remaining in agriculture. Our meta‐analysis shows that soil P content was typically elevated after abandonment compared to reference levels, but reduced compared to soils that remained under agriculture. There were more pronounced differences in the legacies of past agriculture on soil P across regions than between the types of land use practiced prior to abandonment (cropland, pasture, or forage grassland). However, consistent patterns of soil P enrichment or depletion according to soil order and types of post‐agricultural vegetation suggest that these factors may mediate agricultural legacies on soil P. We also used mixed effects models to examine the role of multiple variables on soil P recovery following agriculture. Time since cessation of agriculture was highly influential on soil P legacies, with clear reductions in the degree of labile and total P enrichment relative to reference ecosystems over time. Soil characteristics (clay content and pH) were strongly related to changes in labile P compared to reference sites, but these were relatively unimportant for total P. The duration of past agricultural use and climate were weakly related to changes in total P only. Our finding of reductions in the degree of soil P alteration over time relative to reference conditions reveals the potential to mitigate these land‐use legacies in some soils. Better ability to predict dynamics of soil nutrient recovery after termination of agricultural use is essential to ecosystem management following land‐use change.     

Land-use trends in Endemic Bird Areas: global expansion of agriculture in areas of high conservation value

The impacts of humans on biodiversity tend to be exacerbated by the coincidence of human settlement with areas of high biological value, as demonstrated by regional, continental and global analyses. We present a global analysis, intersecting Endemic Bird Areas (EBAs) with fine‐scale data on changes in agricultural land use for the past 300 years and for four scenarios projecting land use up to 2050. The proportion of land in agricultural use is currently greater in EBAs than in the rest of the world (42.0% vs. 37.0%, respectively), has been historically (in 1700: 9.1% vs. 5.7%, through to 1900: 43.4% vs. 32.1%) and looks set to remain so in the future (44.6–56.1% vs. 37.0–43.2%; depending on scenario). However, the future course of agricultural expansion is more scenario‐dependent in EBAs than in the rest of the world, indicating that development policies have considerable potential to either ease or exacerbate the disproportionate impact of agriculture on areas of highest biological value.     

Increasing terrestrial vegetation activity in China, 1982—1999

The搊pening?policiesimplementedinChinainthepasttwodecadeshaveresultedinextensivechangesinlanduseandlandcover.Vegetationactivityhasincreasedthroughagriculturalpracticessuchasafforestation,irrigation,andintensiveagriculturalmanagement[1,2].Ontheotherhand,vegetationcover-agehasdecreasedduetorapidurbanization,industri-alization,andovergrazing[3,4].Thus,therearecon-flictingreportsregardingthestatusofChina抯vegeta-tion,asnointegrativeanalysisatthenationallevelhasyetbeenconducted.Thisstudyaimstoexpl…     

干旱区受水资源胁迫的下游绿洲动态变化趋势分析——以黑河流域额济纳绿洲为例

干旱内陆流域下游绿洲的形成与演变对流域地表径流变化响应强烈 .采用绿洲生态斑块动态模拟、植被与水盐状态相关分析、生态需水量估算等方法 ,分别对黑河流域下游额济纳绿洲在不同分水方案与水资源利用情景下的变化趋势进行了研究 .结果表明 ,维持现状绿洲面积不再萎缩 ,在考虑水资源利用合理化的前提下 ,其最低净需水量为 5 .7× 10 8m3 ,如果考虑下游地区人畜生活用水及工业用水 ,同时考虑水量在输送过程中的散失损耗 ,为在近期 (2 0 15年以前 )维持现状绿洲面积 ,狼心山断面入境流量需达到6 .0× 10 8m3 ;而要使绿洲面积恢复到 2 0世纪 80年代初的水平 ,狼心山断面过水量应不低于 8.9× 10 8m3 ,正义峡断面下泄水量要求达到 10 .9× 10 8～ 13.1× 10 8m3 .     

Ethnobotany ofAnoda Cristata (L.) schl. (Malvaceae) in central Mexico: Uses, management and population differentiation in the community of Santiago Mamalhuazuca, Ozumba, state of Mexico

Anoda cristata is a common weed used for food and medicine in central Mexico where it grows among field crops during the rainy seasons. People prefer robust, tender plants from the agricultural fields because these “develop better.” Hence, the plants are tolerated within the conventional agricultural activities and benefit indirectly from the improvements in the agrohabitat. People do not select individuals with specific morphological characteristics but rather they select for plants at the level of the habitat. This step may precede that of direct management of individual plants. It is possible that these differences in the level of interaction between humans and plants (i.e., within the ruderal and agrestal habitats) may promote morphological and genetic differences over time,

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Etnobotánica de anoda cristata (Malvaceae) en México: Usos, Manejo y diferenciación poblacional en la Comunidad de Santiago Mamalhuazuca, Ozumba, estado de México

Resumen   Anoda cristata es una maleza muy común utilizada como medicina y alimento en el centro de México durante la época de lluvias La gente prefiere las plantas robustas y tiernas que crecen en los campos de cultivo porque se “desarrollan mejor.”Ahí, las plantas son toleradas dentro de las prácticas agrícolas tradicionales y se benefician indirectamente de las alteraciones que se hacen al agrohabitat. La gente no selecciona conscientemente individuos con características morfológicas específicas, sino que seleccionan a las plantas a nivel del hábitat. Este paso puede ser previo al manejo indirecto de individuos particulares. Es posible que estas diferencias en el nivel de interactión entre los hombres y las plantas (entre el hábitat ruderal y arvense) puede promover diferencias morfológicas y genéticas a través del tiempo.

     

Effect of Agricultural Management on Nematode Communities in a Mediterranean Agroecosystem

The effects of agricultural management on the soil nematode community were investigated in a field study at depths of 0 to 10 cm and 10 to 20 cm during a peanut (Arachis hypogaea) growing season in Israel. Nineteen nematode families and 23 genera were observed. Rhabditidae, Cephalobus, Eucephalobus, Aphelenchus, Aphelenchoides, Tetylenchus, Tylenchus, Dorylaimus, and Discolaimus were the dominant family and genera. Ecological measures of soil nematode community structure, diversity, and maturity indices were assessed and compared between the managed (by fertilization, irrigation, and pesticide application) and unmanaged fields. The total number of nematodes at a 10-cm depth during peanut-sowing, mid-season, and harvest periods was higher in the treated (managed) plot than in the control (unmanaged) plot. Bacterivores and fungivores were the most abundant trophic groups in both plots and both depths. The relative abundance of each group averaged 60.8 to 67.3% and 11.5 to 19.6% of the nematode community, respectively. Plant parasites and omnivores-predators at the 0 to 10-cm depth were much less abundant than any other two groups in our experimental plots. During the growing season, except the harvest period, populations of plant parasites and omnivores-predators at the 10 to 20-cm depth were lower in the treated plot than in the control plot. Maturity index (MI), plant-parasite index (PPI), and ratio of fungivores and bacterivores to plant parasites (WI) were found to be more sensitive indicators than other ecological indices for assessing the response of nematode communities to agricultural management in an Israeli agroecosystem.     

Phosphorus loss from land to water: integrating agricultural and environmental management

Phosphorus (P), an essential nutrient for crop and animal production, can accelerate freshwater eutrophication, now one of the most ubiquitous forms of water quality impairment in the developed world. Repeated outbreaks of harmful algal blooms (e.g., Cyanobacteria and Pfiesteria) have increased society's awareness of eutrophication, and the need for solutions. Agriculture is regarded as an important source of P in the environment. Specifically, the concentration of specialized farming systems has led to a transfer of P from areas of grain production to animal production. This has created regional surpluses in P inputs (mineral fertilizer and feed) over outputs (crop and animal produce), built up soil P in excess of crop needs, and increased the loss of P from land to water. Recent research has shown that this loss of P in both surface runoff and subsurface flow originates primarily from small areas within watersheds during a few storms. These areas occur where high soil P, or P application in mineral fertilizer or manure, coincide with high runoff or erosion potential. We argue that the overall goal of efforts to reduce P loss to water should involve balancing P inputs and outputs at farm and watershed levels by optimizing animal feed rations and land application of P as mineral fertilizer and manure. Also, conservation practices should be targeted to relatively small but critical watershed areas for P export.     

Explaining bird species composition and richness in eucalypt-dominated remnants in subhumid Tasmania

Aim To determine the factors influencing the distribution of birds in remnants in a fragmented agricultural landscape. Location Forty‐seven eucalypt remnants and six sites in continuous forest in the subhumid Midlands region of Tasmania, Australia. Methods Sites were censused over a two‐year period, and environmental data were collected for remnants. The avifauna of the sites was classified and ordinated. The abundances of bird species, and bird species composition, richness, abundance and diversity were related to environmental variables, using simple correlation and modelling. Results There were two distinct groups of sample sites, which sharply differed in species composition, richness, diversity and bird abundance, separated on the presence/absence of noisy miner (Manorina melanocephala Latham) colonies, remnant size, vegetation structural attributes and variables that reflected disturbance history. The approximate remnant size threshold for the change from one group to another was 20–30 ha. Remnant species richness and diversity were most strongly explained by remnant area and noisy miner abundance, with contributions from structural and isolation attributes in the second case. Segment richness was explained by precipitation, logging history and noisy miner abundance. Bird abundance was positively related to precipitation and negatively related to tree dieback. The 28 individual bird species models were highly individualistic, with vegetation structural variables, noisy miner abundance, climatic variables, variables related to isolation, area, variables related to floristics, disturbance variables, the nature of the matrix and remnant shape all being components in declining order of incidence. Age of the remnant did not relate to any of the dependent variables. Main conclusions Degraded and small remnants may have become more distinct in their avifaunal characteristics than might otherwise be the case, as a result of the establishment of colonies of an aggressive native bird, the noisy miner. The area, isolation and shape of remnants directly relate to the abundance of relatively few species, compared to vegetation attributes, climate and the abundance of the noisy miner. The nature of the matrix is important in the response of some species to fragmentation.