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YUNHUI LIU JAN C. AXMACHER CHANGLIU WANG LIANGTAO LI ZHENRONG YU 《Insect Conservation and Diversity》2010,3(1):34-43
Abstract. 1. In the intensively cultivated major crop production areas of China, large knowledge gaps still prevail with regard to the current status of biodiversity in general, and especially in relation to agriculture management and planting patterns. Effective measures for species conservation are hence widely lacking. 2. The diversity of ground beetle (Coleoptera: Carabidae) assemblages was compared between intensively managed wheat/maize fields, cotton monocultures, lawns, orchards and semi‐natural woodland located in Quzhou county, a typical, intensively managed agricultural region in the North China Plain. 3. Although significant differences were found in species composition between different habitats, diversity of ground beetles in non‐cropping sites was not significantly higher than in intensively managed wheat/maize double‐cropping fields, while cotton monocultures had a significant lower carabid diversity. A combination of intensively managed wheat/maize double‐cropping fields with orchards appears to preserve substantial proportions of ground beetle diversity. 4. To conserve the full spectrum of beetle species currently observed in the agricultural landscape of the North China Plain, the creation of both diverse habitats and a diversity of cropping systems are important, which includes a strengthening of less intensive farming practices. 相似文献
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Threatened species that exist in small isolated populations are vulnerable to extinction processes, so effectively monitoring the trajectory of such populations will help determine the most appropriate management actions to combat extinction threats. In this study, we aimed to track the population status of the fossorial heath skink Liopholis multiscutata that is listed as threatened in Victoria, south‐eastern Australia, and exists there as a few small and highly disjunct populations, by using an appropriate surrogate population monitoring metric. This secretive lizard is a habitat specialist, is highly localised in Victoria and lives in warrens in semi‐arid heathland or mallee on large dunes. Survey data, which included every warren and their constituent burrows, as well as an assessment of whether each burrow was ‘active’, were collected for the four known Victorian populations in 2007 and annually during 2014–2018 inclusive. We compared five population indices per monitoring site: number of active warrens (NAW), number of active burrows (NAB), population area for 80% of active warrens (PA80), percentage of warrens that were active (PAW) and average number of active burrows per active warren. The heath skink currently occurs in small populations (8–46 active warrens) and these populations have typically declined over recent years. NAW was the most robust metric; NAB and PA80 did not reveal strong temporal trends. PAW indicated that inactive warrens and burrows persist less than a year and hence may provide information about recent (within months) population changes. It is imperative to establish a material link between the effective monitoring of small, vulnerable populations and the implementation of management actions that benefit such populations. Here, NAW could be used as a long‐term monitoring tool to provide an estimate of the minimum population size of the heath skink at a site. Its use would also ensure continuity in monitoring approaches for the Victorian populations. 相似文献
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A species distribution may be determined by its responses to patterns of human disturbance as well as by its habitat preferences. Here we investigate the distribution of the Upland Goose Chloephaga picta, which has been historically persecuted by farmers and ranchers in Patagonia because it feeds on crops and pastures and is assumed to compete with sheep for forage. We assess whether its current breeding distribution is shaped by persecution by ranchers or whether it can be better explained by differences in habitat primary productivity and preference for wetlands, or by other anthropogenic disturbances not associated with ranching. We built species distribution models to examine the relative effect of environmental and anthropogenic predictors on the regional distribution of Upland Goose. We performed vehicle surveys in the province of Santa Cruz, Argentina, in two years, surveying 8000 km of roads and recording 6492 Geese. Generalized additive models were used to model the presence/absence of Geese in 1‐km cells. The models suggested that Upland Goose distribution is not currently affected by rancher control, as the species is more abundant in areas with high sheep stocking levels, but it is positively influenced by primary productivity and negatively influenced by urban areas. Anthropogenic disturbance caused by urban areas and oil extraction camps had a greater impact in limiting the species distribution than sheep ranching. 相似文献
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Tree hollows are a critical but diminishing resource for a wide range of fauna around the world. Conservation of these fauna depends on sustainable management of tree species that produce the hollows on which they depend. This study addressed the need for empirical data about intraspecific and interspecific variation in hollow occurrence and abundance in woodland trees in Australia. We measured and performed hollow surveys on 1817 trees of seven species of woodland Eucalyptus in central‐western New South Wales, Australia. Trees were surveyed at 51 one‐hectare sites and about 30% of trees surveyed had multiple stems. Generalized linear mixed models that accounted for nestedness of stems within trees and trees within sites detected a significant amount of variation in hollow occurrence and abundance. Models for individual tree stems of live trees showed hollow probability and abundance increased with diameter at breast height (DBH) and with increasing senescence (form). Stems of Eucalyptus microcarpa Maiden had a higher probability of having hollows than similar DBH stems of Eucalyptus camaldulensis Dehnh., Eucalyptus melliodora A.Cunn. ex Schauer or Eucalyptus populnea ssp. bimbil L.A.S.Johnson & K.D.Hill. Dead stems in live trees were more likely to have hollows than live stems of similar DBH. Each stem in a multi‐stemmed tree had a lower probability of hollow occurrence and lower abundance of hollows than single‐stemmed trees of similar DBH. For stems of dead trees, hollow occurrence and abundance increased with DBH and differed depending on stage of senescence. A comparison of our data with other studies indicates regional variation of hollow abundances within tree species. 相似文献
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Editors' Introduction: Birds and Agriculture 总被引：1，自引：2，他引：1
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Marcos Vinicius Meiado Mariana Rojas‐Aréchiga José Alves de Siqueira‐Filho Inara Roberta Leal 《Plant Species Biology》2016,31(2):87-97
Environmental factors are used by plants as spatio‐temporal indicators of favorable conditions for seed germination. Thus, the objective of this study was to determine the effect of light and temperature on seed germination of 30 taxa of Cactaceae occurring in northeastern Brazil and to evaluate whether fluctuations in temperature are capable of altering light sensitivity. The seeds were tested for germination under two light conditions (12 h photoperiod and continuous darkness) and 10 temperature treatments: eight constant temperatures (10, 15, 20, 25, 30, 35, 40 and 45°C) and two alternating temperatures (30/20°C and 35/25°C). The species studied showed two photoblastic responses. All cacti from the Cactoideae subfamily (22 taxa) were classified as positive photoblastic (i.e., no germination in darkness), regardless of the temperature treatment used. Likewise, temperature fluctuation did not alter the seed sensitivity to light. On the other hand, the species of the Opuntioideae (five taxa) and Pereskioideae (three taxa) subfamilies are indifferent to light (i.e., germinated both in the presence and absence of light). The cacti from the areas of Caatinga and Cerrado showed an optimal germination temperature of 30°C, while the species from Atlantic Forest and Restinga areas showed an optimal germination temperature of 25°C. 相似文献
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Guo‐Yue Niu Peter A. Troch Claudio Paniconi Russell L. Scott Matej Durcik Xubin Zeng Travis Huxman David Goodrich Jon Pelletier 《Ecohydrology》2014,7(2):815-827
In water‐limited regions, surface water and carbon fluxes are strongly controlled by soil water availability, which may be highly variable at very small spatial scales (e.g. metres) because of variations in terrain, soils, and vegetation conditions and to processes of water redistribution along hillslopes. This second of a two‐part paper first evaluates the performance of a newly developed ecohydrological model over a small semi‐arid experimental catchment (7·92 ha) in southeastern Arizona. Secondly, it investigates the effects of soil properties on water subsidy resulting from lateral overland flow re‐infiltration and on overall ecohydrological response. With optimized parameters, the model shows a higher ability to simulate surface energy and water fluxes than CO2 fluxes at all temporal scales. The model simulates observed CO2 fluxes fairly well at diurnal scales during the main growing seasons and the interannual variability of these fluxes in response to soil moisture variations from drought years to wet years. However, the model reproduces less well carbon assimilation in spring and positive CO2 flux pulses following early monsoon rain events, suggesting a need for further development of the model's representations of multiple plant species and soil carbon decomposition. The model simulates soil moisture at 5 cm much better than at 15 cm mainly because of heterogeneous soil properties. Through five numerical experiments with varying saturated hydraulic conductivity values, it is revealed that the discharge at the outlet of this semi‐arid catchment is essentially attributed to lateral overland flow that is generated mainly by infiltration‐excess runoff. Subsurface flow plays a minor role in this semi‐arid catchment with a very deep groundwater table (>100 m). The model produces wetter soils in lowland areas along stream rills and channels through re‐infiltration of lateral overland flow. This water subsidy provides plants with favourable conditions to produce more leaves, CO2, and ET fluxes in lowland areas. Re‐infiltration of overland flow over complex terrain may play a role in buffering climatic impacts in a warming climate with fewer but more intense rainfall events in the Southwestern United States. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Mónica E. Riojas‐López Eric Mellink Francis Raoul Jaime Luévano Amélie Vaniscotte Patrick Giraudoux 《Diversity & distributions》2011,17(4):739-747
Aim The Llanos de Ojuelos in Mexico’s Central High Plateau supports unique Opuntia scrublands and the southernmost Chihuahuan grasslands. Although human activities have modified strongly its landscape and impacted its biodiversity at an unknown scale, such impacts are poorly known. We aimed at understanding how nocturnal rodent species distributed across the landscape and formed assemblages and on the role and integration of the different habitats at the landscape level. Location The study was carried out at 43 sites in a study area of approximately 3350 km2 in the Llanos de Ojuelos. Methods During the Spring of 2008, we surveyed nocturnal rodents, through live‐trapping. We redefined habitat classes based on log‐linear multinomial regressions of rodent captures. Species rarefaction curves and true alpha, beta and gamma diversities were calculated for the different habitat classes. A map of the different habitats was constructed based on Landsat imagery. Results We captured 458 individuals of 20 rodent species. Multinomial regressions caused the merger of 11 a priori defined habitat classes into 7. Leguminous scrub and mixed nopaleras, both secondary habitats, had the highest alpha and gamma diversity values. Closed arboreal nopaleras and grasslands had the highest within‐habitat variability (1Dβ) and the lowest area coverage. Within‐habitat 1Dβ was larger than landscape 1Dβ, because of the great overlap in rodent assemblage composition between the habitats. Main conclusions There are no ‘typical’ rodent assemblages per habitat class, but they are organized loosely and have fuzzy borders. Rodent community organization was highly species‐centred. At the landscape level, secondary habitats have a profound effect on rodent diversity and should be included in management schemes for biological conservation. The most endangered habitats seem to be the closed arboreal nopaleras and grasslands. Any conservation efforts must consider their conservation and an increase in the size of remaining patches. 相似文献
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László Erdős Didem Ambarlı Oleg A. Anenkhonov Zoltán Bátori Dániel Cserhalmi Márton Kiss György Kröel‐Dulay Hongyan Liu Martin Magnes Zsolt Molnár Alireza Naqinezhad Yury A. Semenishchenkov Csaba Tölgyesi Péter Török 《应用植被学》2018,21(3):345-362
Aims
Eurasian forest‐steppes are among the most complex non‐tropical terrestrial ecosystems. Despite their considerable scientific, ecological and economic importance, knowledge of forest‐steppes is limited, particularly at the continental scale. Here we provide an overview of Eurasian forest‐steppes across the entire zone: (a) we propose an up‐to‐date definition of forest‐steppes, (b) give a short physiogeographic outline, (c) delineate and briefly characterize the main forest‐steppe regions, (d) explore forest‐steppe biodiversity and conservation status, and (e) outline forest‐steppe prospects under predicted climate change.Location
Eurasia (29°–56°N, 16°–139°E).Results and Conclusions
Forest‐steppes are natural or near‐natural vegetation complexes of arboreal and herbaceous components (typically distributed in a mosaic pattern) in the temperate zone, where the co‐existence of forest and grassland is enabled primarily by the semi‐humid to semi‐arid climate, complemented by complex interactions of biotic and abiotic factors operating at multiple scales. This new definition includes lowland forest–grassland macromosaics (e.g. in Eastern Europe), exposure‐related mountain forest‐steppes (e.g. in Inner Asia), fine‐scale forest–grassland mosaics (e.g. in the Carpathian Basin) and open woodlands (e.g. in the Middle East). Using criteria of flora, physiognomy, relief and climate, nine main forest‐steppe regions are identified and characterized. Forest‐steppes are not simple two‐phase systems, as they show a high level of habitat diversity, with forest and grassland patches of varying types and sizes, connected by a network of differently oriented edges. Species diversity and functional diversity may also be exceptionally high in forest‐steppes. Regarding conservation, we conclude that major knowledge gaps exist in determining priorities at the continental, regional, national and local levels, and in identifying clear target states and optimal management strategies. When combined with other threats, climate change may be particularly dangerous to forest‐steppe survival, possibly resulting in compositional changes, rearrangement of the landscape mosaic or even the latitudinal or altitudinal shift of forest‐steppes. 相似文献13.
Mathieu Thomas Stéphanie Thépot Nathalie Galic Sophie Jouanne‐Pin Carine Remoué Isabelle Goldringer 《Molecular ecology》2015,24(12):2937-2954
While modern agriculture relies on genetic homogeneity, diversifying practices associated with seed exchange and seed recycling may allow crops to adapt to their environment. This socio‐genetic model is an original experimental evolution design referred to as on‐farm dynamic management of crop diversity. Investigating such model can help in understanding how evolutionary mechanisms shape crop diversity submitted to diverse agro‐environments. We studied a French farmer‐led initiative where a mixture of four wheat landraces called ‘Mélange de Touselles’ (MDT) was created and circulated within a farmers' network. The 15 sampled MDT subpopulations were simultaneously submitted to diverse environments (e.g. altitude, rainfall) and diverse farmers' practices (e.g. field size, sowing and harvesting date). Twenty‐one space‐time samples of 80 individuals each were genotyped using 17 microsatellite markers and characterized for their heading date in a ‘common‐garden’ experiment. Gene polymorphism was studied using four markers located in earliness genes. An original network‐based approach was developed to depict the particular and complex genetic structure of the landraces composing the mixture. Rapid differentiation among populations within the mixture was detected, larger at the phenotypic and gene levels than at the neutral genetic level, indicating potential divergent selection. We identified two interacting selection processes: variation in the mixture component frequencies, and evolution of within‐variety diversity, that shaped the standing variability available within the mixture. These results confirmed that diversifying practices and environments maintain genetic diversity and allow for crop evolution in the context of global change. Including concrete measurements of farmers' practices is critical to disentangle crop evolution processes. 相似文献
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Rodrigo L. Massara Ana Maria de Oliveira Paschoal Larissa L. Bailey Paul F. Doherty Jr André Hirsch Adriano G. Chiarello 《Biotropica》2018,50(1):125-134
Over 80% of Atlantic Forest remnants are <50 ha and protected areas are embedded in a matrix dominated by human activities, undermining the long‐term persistence of carnivores. The ocelot (Leopardus pardalis) is an opportunistic species, but little is known about its tolerance to habitat alterations and the influence of other species on its occupancy in Atlantic Forest remnants. We used camera traps to assess ocelot occupancy in protected areas of Atlantic Forest in southeastern Brazil. We found a positive correlation between the occupancy of ocelots and top predators (jaguars, Panthera onca, and pumas, Puma concolor), and a weaker negative effect between the number of domestic dogs (Canis familiaris) detected and ocelot occupancy. Ocelot detection was higher at sites with more eucalyptus, suggesting that ocelots frequently use these areas. Better‐protected areas surrounded by permeable matrices may be critical to the persistence of ocelots in the fragmented Atlantic Forest. 相似文献
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We investigate local lizard richness and distribution in central Brazilian Cerrado, harbouring one of the least studied herpetofaunas in the Neotropical region. Our results are based on standardized samplings at 10 localities, involving 2917 captures of 57 lizard species in 10 families. Local richness values exceeded most presented in earlier studies and varied from 13 to 28 species, with modal values between 19 and 28 species. Most of the Cerrado lizard fauna is composed of habitat‐specialists with patchy distributions in the mosaic of grasslands, savannas and forests, resulting in habitat‐structured lizard assemblages. Faunal overlap between open and forested habitats is limited, and forested and open areas may act as mutual barriers to lizard distribution. Habitat use is influenced by niche conservatism in deep lineages, with iguanians and gekkotans showing higher use of forested habitats, whereas autarchoglossans are richer and more abundant in open habitats. Contrary to trends observed in Cerrado birds and large mammals, lizard richness is significantly higher in open, interfluvial habitats that dominate the Cerrado landscape. Between‐localities variation in lizard richness seems tied to geographical distance, landscape history and phylogenetic constraints, factors operating in other well‐studied lizard faunas in open environments. Higher richness in dominant, open interfluvial habitats may be recurrent in Squamata and other small‐bodied vertebrates, posing a threat to conservation as these habitats are most vulnerable to the fast, widespread and ongoing process of habitat destruction in central Brazil. 相似文献
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Agricultural activities represent a global threat to biodiversity, yet little is known about the relative importance of different agricultural land uses in relation to their wildlife communities. We explored bird community structure, diversity, and composition in a landscape dominated by primary tropical dry forest, and in three agricultural systems (i.e., tree orchards, herbaceous cropfields, cattle pastures) to evaluate the way in which birds use different habitats within the landscape. Tropical dry forests had the highest species richness and community evenness, although the bird community in tree orchards was also relatively species rich and even. Cattle pastures had more bird species than cropfields but both habitats were comparatively species poor with low evenness. Our results are related to habitat structure and the spatial location of sites within the landscape matrix. Based on our observations, we recommend including native tree species within agricultural systems and surrounding areas to provide additional resources for birds. Finally, we suggest promoting natural recruitment of native trees and shrubs within cattle pastures to provide suitable habitat for species that use tropical dry forest plants. Abstract in Spanish is available at http://www.blackwell‐synergy.com/loi/btp . 相似文献
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Five sets of herbivore exclosures situated in mesic and semi‐arid savannas in Hluhluwe‐iMfolozi Park, South Africa were used to investigate the effects of mammal browsers and savanna type on plant traits relating to leaf nutrient content, defense, and growth in seven Acacia species. Mostly, browsing did not significantly affect leaf nutrient content but for a few species (i.e., increasing foliar N and P, decreasing C/N, and total polyphenols). Browser effects on structural defenses tended to be more pronounced than for leaf nutrient content and chemical defenses, particularly for semi‐arid species, resulting in longer, thicker, and denser spines, and a lower bite size index on browsed plants for most semi‐arid species. Browsing had no significant effect on growth rates for all species. Secondly, we investigated the effect of savanna type (mesic vs. semi‐arid) on the same set of plant traits and growth rates. A trade‐off in defense strategy was evident where mesic species had lower quality leaves and invested more heavily in growth and chemical defenses, while semi‐arid species generally had higher nutrient content leaves and invested more in structural defenses and higher levels of ramification. These findings suggest that the previously documented trade‐off in plant growth, resprouting ability and architecture between herbivore versus fire‐adapted savanna woody species can possibly be extended to include browse quality and defense type. 相似文献
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Hongyan Liu A. Park Williams Craig D. Allen Dali Guo Xiuchen Wu Oleg A. Anenkhonov Eryuan Liang Denis V. Sandanov Yi Yin Zhaohuan Qi Natalya K. Badmaeva 《Global Change Biology》2013,19(8):2500-2510
Forests around the world are subject to risk of high rates of tree growth decline and increased tree mortality from combinations of climate warming and drought, notably in semi‐arid settings. Here, we assess how climate warming has affected tree growth in one of the world's most extensive zones of semi‐arid forests, in Inner Asia, a region where lack of data limits our understanding of how climate change may impact forests. We show that pervasive tree growth declines since 1994 in Inner Asia have been confined to semi‐arid forests, where growing season water stress has been rising due to warming‐induced increases in atmospheric moisture demand. A causal link between increasing drought and declining growth at semi‐arid sites is corroborated by correlation analyses comparing annual climate data to records of tree‐ring widths. These ring‐width records tend to be substantially more sensitive to drought variability at semi‐arid sites than at semi‐humid sites. Fire occurrence and insect/pathogen attacks have increased in tandem with the most recent (2007–2009) documented episode of tree mortality. If warming in Inner Asia continues, further increases in forest stress and tree mortality could be expected, potentially driving the eventual regional loss of current semi‐arid forests. 相似文献