试论矿山环评中的生态恢复评价问题

矿山生态恢复是矿山环保对策中的一项技术较强的措施之一，它既有防治水土流失的功能，又有降解有毒污染的功能，并能产生较好的经济效益。但没有科学依据而盲目进行生态恢复，就有可能对环境和人类带来风险，为减少风险，在矿山开发前的环境影响评价中，就应对生态恢复这一措施进行评价，提出合理的恢复模式，为决策部门提供科学依据。     

Designing Impact Assessments for Evaluating Ecological Effects of Agricultural Conservation Practices on Streams1

Abstract: Conservation practices are regularly implemented within agricultural watersheds throughout the United States without evaluating their ecological impacts. Impact assessments documenting how habitat and aquatic biota within streams respond to these practices are needed for evaluating the effects of conservation practices. Numerous sampling protocols have been developed for monitoring streams. However, protocols designed for monitoring studies are not appropriate for impact assessments. We developed guiding principles for designing impact assessments of ecological responses to conservation practices. The guiding principles are as follows: (1) develop the hypothesis first, (2) use replicated experimental designs having controls and treatments, (3) assess the habitat and biological characteristics with quantitative and repeatable sampling methods, (4) use multiple sampling techniques for collecting aquatic organisms, and (5) standardize sampling efforts for aquatic organisms. The guiding principles were applied in designing a study intended to evaluate the influence of herbaceous riparian buffers on channelized headwater streams in central Ohio. Our example highlights that the application of our recommendations will result in impact assessments that are hypothesis‐driven and incorporate quantitative methods for the measurement of abiotic and biotic attributes.     

Relations between Urban Bird and Plant Communities and Human Well‐Being and Connection to Nature

Abstract: By 2050, 70% of the world's population will live in urban areas. In many cases urbanization reduces the richness and abundance of native species. Living in highly modified environments with fewer opportunities to interact directly with a diversity of native species may adversely affect residents’ personal well‐being and emotional connection to nature. We assessed the personal well‐being, neighborhood well‐being (a measure of a person's satisfaction with their neighborhood), and level of connection to nature of over 1000 residents in 36 residential neighborhoods in southeastern Australia. We modeled these response variables as a function of natural features of each neighborhood (e.g., species richness and abundance of birds, density of plants, and amount of vegetation cover) and demographic characteristics of surveyed residents. Vegetation cover had the strongest positive relations with personal well‐being, whereas residents’ level of connection to nature was weakly related to variation in species richness and abundance of birds and density of plants. Demographic characteristics such as age and level of activity explained the greatest proportion of variance in well‐being and connection to nature. Nevertheless, when controlling for variation in demographic characteristics (examples were provided above), neighborhood well‐being was positively related to a range of natural features, including species richness and abundance of birds, and vegetation cover. Demographic characteristics and how well‐being was quantified strongly influenced our results, and we suggest demography and metrics of well‐being must be considered when attempting to determine relations between the urban environment and human well‐being.     

The Role of Botanic Gardens in the Science and Practice of Ecological Restoration

Abstract: Many of the skills and resources associated with botanic gardens and arboreta, including plant taxonomy, horticulture, and seed bank management, are fundamental to ecological restoration efforts, yet few of the world's botanic gardens are involved in the science or practice of restoration. Thus, we examined the potential role of botanic gardens in these emerging fields. We believe a reorientation of certain existing institutional strengths, such as plant‐based research and knowledge transfer, would enable many more botanic gardens worldwide to provide effective science‐based support to restoration efforts. We recommend botanic gardens widen research to include ecosystems as well as species, increase involvement in practical restoration projects and training practitioners, and serve as information hubs for data archiving and exchange.     

Progress in global ecological modelling

The development of ecological modelling on global level since the middle of the 19th century is first reviewed, including application of statistical analysis, introduction of logistic curve, earth surface modeling, systems ecology, computer-oriented mathematical models and spatially explicit models. Finally, we discuss problems existing in ecological modelling on global level.     

Regional Decline of an Iconic Amphibian Associated with Elevation,Land‐Use Change,and Invasive Species

Abstract: Ecological theory predicts that species with restricted geographic ranges will have the highest probability of extinction, but species with extensive distributions and high population densities can also exhibit widespread population losses. In the western United States populations of northern leopard frogs (Lithobates pipiens)—historically one of the most widespread frogs in North America—have declined dramatically in abundance and geographic distribution. To assess the status of leopard frogs in Colorado and evaluate causes of decline, we coupled statewide surveys of 196 historically occupied sites with intensive sampling of 274 wetlands stratified by land use. We used an information‐theoretic approach to evaluate the contributions of factors at multiple spatial extents in explaining the contemporary distribution of leopard frogs. Our results indicate leopard frogs have declined in Colorado, but this decline was regionally variable. The lowest proportion of occupied wetlands occurred in eastern Colorado (2–28%), coincident with urban development and colonization by non‐native bullfrogs (Lithobates catesbeianus). Variables at several spatial extents explained observed leopard frog distributional patterns. In low‐elevation wetlands introduced fishes, bullfrogs, and urbanization or suburbanization associated negatively with leopard frog occurrence, whereas wetland area was positively associated with occurrence. Leopard frogs were more abundant and widespread west of the Continental Divide, where urban development and bullfrog abundance were low. Although the pathogenic chytrid Batrachochytrium dendrobatidis (Bd) was not selected in our best‐supported models, the nearly complete extirpation of leopard frogs from montane wetlands could reflect the individual or interactive effects of Bd and climate patterns. Our results highlight the importance of considering multiple, competing hypotheses to explain species declines, particularly when implicated factors operate at different spatial extents.     

Pattern-oriented modeling of bird foraging and pest control in coffee farms

We develop a model of how land use and habitat diversity affect migratory bird populations and their ability to suppress an insect pest on Jamaican coffee farms. Bird foraging—choosing which habitat patch and prey to use as prey abundance changes over space and time—is the key process driving this system. Following the “pattern-oriented” modeling strategy, we identified nine observed patterns that characterize the real system's dynamics. The model was designed so that these patterns could potentially emerge from it. The resulting model is individual-based, has fine spatial and temporal resolutions, represents very simply the supply of the pest insect and other arthropod food in six habitat types, and includes foraging habitat selection as the only adaptive behavior of birds. Although there is an extensive heritage of bird foraging theory in ecology, most of it addresses only the individual level and is too simple for our context. We used pattern-oriented modeling to develop and test foraging theory for this across-scale problem: rules for individual bird foraging that cause the model to reproduce a variety of patterns observed at the system level. Four alternative foraging theories were contrasted by how well they caused the model to reproduce the nine characteristic patterns. Four of these patterns were clearly reproduced with the “null” theory that birds select habitat randomly. A version of classical theory in which birds stay in a patch until food is depleted to some threshold caused the model to reproduce five patterns; this theory caused lower, not higher, use of habitat experiencing an outbreak of prey insects. Assuming that birds select the nearby patch providing highest intake rate caused the model to reproduce all but one pattern, whereas assuming birds select the highest-intake patch over a large radius produced an unrealistic distribution of movement distances. The pattern reproduced under none of the theories, a negative relation between bird density and distance to trees, appears to result from a process not in the model: birds return to trees at night to roost. We conclude that a foraging model for small insectivorous birds in diverse habitat should assume birds can sense higher food supply but over short, not long, distances.     

Weed Interference on Maize (Zea mays) Under No Tillage System

Abstract

A field trial was carried out in Brazil in March 2002 with the aim to evaluate the effects of different timing and extension of weedy period on maize productivity. The hybrid Pioneer 30K75 was sowed under 7 t ha^?1 mulching promoted by glyphosate spraying. The treatments were divided in two groups: In the first group, weeds were maintained since the maize sowing until different periods in the crop cycle: 0, 14, 28, 42, 56, 70, and 150 days (harvesting time). In the second group, the maize crop was kept weed free for the same periods of the first group. Weed control was done through hand hoeing. A complete randomized blocks experimental design with five replications was used for plots distribution in the field. Nonlinear regression model was used to study the effects of weedy or weedfree periods on maize productivity. Weed community included 13 families and 31 species. Asteraceae, Poaceae, and Euphorbiaceae were the most abundant families. Results showed that under no tillage condition with 7 t ha^?1 mulching at sowing time, the maize crop could cohabit with weed community for 54 days without any yield lost. On the other hand, if the crop was kept weed free for 27 days, the weed interference was not enable to reduce maize production. According to these results one weed control measure between 27 and 54 days after crop emergence could be enough to avoid any reduction in maize productivity.     

Advancing the Integration of History and Ecology for Conservation

Abstract: The important role of humans in the development of current ecosystems was recognized decades ago; however, the integration of history and ecology in order to inform conservation has been difficult. We identified four issues that hinder historical ecological research and considered possible solutions. First, differences in concepts and methods between the fields of ecology and history are thought to be large. However, most differences stem from miscommunication between ecologists and historians and are less substantial than is usually assumed. Cooperation can be achieved by focusing on the features ecology and history have in common and through understanding and acceptance of differing points of view. Second, historical ecological research is often hampered by differences in spatial and temporal scales between ecology and history. We argue that historical ecological research can only be conducted at extents for which sources in both disciplines have comparable resolutions. Researchers must begin by clearly defining the relevant scales for the given purpose. Third, periods for which quantitative historical sources are not easily accessible (before AD 1800) have been neglected in historical ecological research. Because data from periods before 1800 are as relevant to the current state of ecosystems as more recent data, we suggest that historical ecologists actively seek out data from before 1800 and apply analytic methods commonly used in ecology to these data. Fourth, humans are not usually considered an intrinsic ecological factor in current ecological research. In our view, human societies should be acknowledged as integral parts of ecosystems and societal processes should be recognized as driving forces of ecosystem change.     

Using Parasitic Trematode Larvae to Quantify an Elusive Vertebrate Host

Abstract: Digenean trematode parasites require multiple host species to complete their life cycles, and their abundance can often be strongly correlated with the abundance of their host species. Species richness and abundance of parasites in easily sampled host species may yield an accurate estimate of the species richness and abundance of other hosts in a parasite's life cycle that are difficult to survey directly. Accordingly, we investigated whether prevalence and mean abundance of trematodes could be used to estimate the abundance of one of their host species, diamondback terrapins (Malaclemys terrapin), which are difficult to sample and are designated as near threatened (by the International Union for Conservation of Nature [IUCN Red List]) along some U.S. coasts. As an adult the trematode Pleurogonius malaclemys is specific to terrapins. Its larval stages live first inside mud snails (Ilyanassa obsoleta) and are subsequently shed into the environment where they form external metacercarial cysts on hard surfaces such as snail opercula. The life cycle of P. malaclemys is completed when terrapins ingest these cysts. At 12 sites along the coast of Georgia (U.S.A.), we determined the prevalence of internal P. malaclemys larvae in mud snails (proportion of infected snails in a population) and the prevalence and mean abundance of external trematode cysts. We examined whether these data were correlated with terrapin abundance, which we estimated with mark‐recapture methods. The abundance of external cysts and salinity explained ≥59% of the variability in terrapin abundance. We suggest that dependent linkages between the life stages of multihost parasites make them reliable predictors of host species’ abundance, including hosts with abundances that are challenging to quantify directly.