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1.
The present study aims to establish a long‐term intercontinental collaboration based on a sampling protocol using standardized repeated measures at permanent sites to document macromoth species richness and abundance through time and across the landscape. We pooled the data from two continental regions providing a total of 12 trap sites: Mt. Jirisan National Park in South Korea (2005–2007) and HJ Andrews Experimental Forest in Oregon, USA. (2004–2006). A synthesis of our data indicated that: (i) noctuids (43–52%) and geometrids (33–39%) dominated the measures of species richness; (ii) using our sampling protocols more than three years would be needed to obtain a value of 90% of empirical species richness relative to Chao‐1 estimated species richness; (iii) temperature alone could not explain the peak pattern in moth abundance and species richness; (iv) the highest/lowest proportion of species richness and abundance were present in similar elevation and forest sites. These observations established a foundation for developing a network‐oriented database for assessing biotic impact of environmental and contributed to identifying species at high risk to environmental change based on empirical measures of temporal and spatial breadth. 相似文献
2.
In this study, we have analysed the series of daily air temperatures from 1977 to 2009 measured in a sedge‐grass marsh ecosystem near the town of Třeboň, Czech Republic (Central Europe). Annual averages of daily mean, minimum and maximum temperatures were analysed. Possible significant increases were recorded for all these values during the study period. The annual average of daily maximum temperatures increased on average by 0.0827 °C per year. The annual average of daily mean air temperatures increased by 0.0544 °C per year. The rise of the annual average of daily minimum air temperature was the lowest, namely by 0.0374 °C per year. The air temperature rise was not the same in all periods of the year, and different increases were found in individual months. The daily mean air temperature rose significantly in the growing season (April–August). In all the other months except December, a statistically non‐significant rise of daily mean air temperatures was recorded. From the ecological point of view, the different monthly increases are more important for the wetland ecosystem than the slow gradual rise of air temperature over the years. The air temperature rise recorded in the wetland studied was lower than that predicted by climatic models. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
3.
Jeremy D. Hogan Katharine M. Jack Fernando A. Campos Urs Kalbitzer Linda M. Fedigan 《American journal of primatology》2019,81(7)
Primates have long been used as indicator species for assessing overall ecosystem health. However, area‐wide census methods are time consuming, costly, and not always feasible under many field conditions. Therefore, it is important to establish whether monitoring a subset of a population accurately reflects demographic changes occurring in the population at large. Over the past 35 years, we have conducted 15 area‐wide censuses in Sector Santa Rosa, Costa Rica. These efforts have revealed important trends in population growth patterns of capuchin monkeys following the protection and subsequent regeneration of native forests. During this same period, we have also intensively studied a subset of the capuchin groups. Comparing these two datasets, we investigate whether the population structures of the closely monitored groups are reliable indicators of area‐wide demographic patterns. We compare the overall group size and the individual age/sex class compositions of study groups and nonstudy groups (i.e., those contacted during area‐wide censuses only). Our study groups contained more individuals overall with a larger proportion of infants, and there were indications that the proportion of adult and subadult males was lower. These differences can be ascribed either to sampling errors or real differences attributable to human presence and/or better habitat quality for the study groups. No other sex/age classes differed, and major demographic changes were simultaneously evident in both study and nonstudy groups. This study suggests that the Santa Rosa capuchin population is similarly impacted by large‐scale ecological patterns observable within our study groups. 相似文献
4.
David Lamb 《Ecological Management & Restoration》2017,18(3):200-204
Many important ecological management issues can only be addressed by long‐term monitoring or through studies carried out over extended periods. But such studies require institutional settings that ensure funding is sustained and that data arising from these studies are securely managed. Recent experience suggests both are difficult to achieve. This is because management agencies and research bodies are periodically restructured, especially in recent years. This has often led to long‐term work being terminated. But there is anecdotal evidence that the data collected in at least some of these studies are not always lost. Instead, it can remain stored in the back rooms of agencies or in the personal files of former staff. Such data are clearly at risk; with time fewer people remain aware of the work or of the existence of data that were collected, thereby increasing the likelihood that the information will eventually disappear. This seems a waste. Securing funds for any long‐term ecological study is always likely to be difficult, and many of these previous long‐term studies are likely to be relevant to some of our present management problems. One approach to taking advantage of these earlier studies would be to ask scientific and professional associations to survey their older members to identify relevant previous investigations. But any re‐establishment of former studies will require the creation of new institutional arrangements, more robust institutional memories and sufficient funds that are able to sustain any resurrected investigations into the future. 相似文献
5.
Chris C. Nice Matthew L. Forister Joshua G. Harrison Zachariah Gompert James A. Fordyce James H. Thorne David P. Waetjen Arthur M. Shapiro 《Global Change Biology》2019,25(6):2127-2136
Certain general facets of biotic response to climate change, such as shifts in phenology and geographic distribution, are well characterized; however, it is not clear whether the observed similarity of responses across taxa will extend to variation in other population‐level processes. We examined population response to climatic variation using long‐term incidence data (collected over 42 years) encompassing 149 butterfly species and considerable habitat diversity (10 sites along an elevational gradient from sea level to over 2,700 m in California). Population responses were characterized by extreme heterogeneity that was not attributable to differences in species composition among sites. These results indicate that habitat heterogeneity might be a buffer against climate change and highlight important questions about mechanisms maintaining interpopulation differences in responses to weather. Despite overall heterogeneity of response, population dynamics were accurately predicted by our model for many species at each site. However, the overall correlation between observed and predicted incidence in a cross validation analysis was moderate (Pearson's r = 0.23, SE 0.01), and 97% of observed data fell within the predicted 95% credible intervals. Prediction was most successful for more abundant species as well as for sites with lower annual turnover. Population‐level heterogeneity in response to climate variation and the limits of our predictive power highlight the challenges for a future of increasing climatic variability. 相似文献
6.
Abstract There is strong demand for information about the status of, and trends in, Australia's biodiversity. Almost inevitably, this demand for information has led to demand for a broad‐scale monitoring system. However, the decision to embark on a monitoring system should only be made once it has been established that a monitoring system is the optimal way to inform management. We stress the need to invest resources in assessing whether a monitoring system is necessary before committing resources to the design and implementation of the system. Current debate associated with the design of a biodiversity monitoring system has similarities to the debate within the range management profession in the early 1970s. The experience with range monitoring shows that large‐scale monitoring systems such as those being proposed will require considerable resources, recurrently expended into the distant future, but with only a limited ability to adapt to new demands. Those involved in any biodiversity monitoring system will need to understand the implications of investing in a long‐term monitoring programme. Monitoring sustainability will only be possible if the monitoring system is itself sustainable. We discuss a number of issues that need to be addressed before the system is at all sustainable. These attributes are a mix of biophysical, social and institutional attributes and highlight the view that monitoring systems of the type being suggested comprise an unusual mixture of attributes not found in typical scientific activity. The present paper is not a technical manual, but rather considers some of the design issues associated with designing and implementing large‐scale monitoring systems. 相似文献
7.
8.
Maare Marttila Pauliina Louhi Ari Huusko Aki Mki‐Petys Timo Yrjn Timo Muotka 《Ecohydrology》2016,9(2):280-289
Studies on the effectiveness of in‐stream restoration have generally reported increased habitat heterogeneity, but biological responses have been more variable. One hypothesis states that the restored habitat structure does not persist through time, resulting in fading biological responses. We studied the durability of in‐stream restoration in northern and central Finland by assessing short‐term (0–1 years) and long‐term (≥10 years) changes in habitat structure after restoration. In 2010, we repeated the field surveys first conducted in the 1990s in 27 stream reaches. We also made similar habitat measurements in ten near‐pristine sites. Restoration caused significant changes in the stream habitat that either remained unaltered or were reinforced through time, with several of the restored sites resembling closely the near‐pristine reference sites 10–20 years post‐restoration. Cover of aquatic mosses initially decreased sharply but recovered close to near‐pristine level within about 15 years. However, substrate variability still remained somewhat lower in the restored than in near‐pristine streams. Individual restoration structures had changed little over time. The most evident failures were the disappearance and entrenchment of gravel beds. Restoration of our study sites had shifted the sites to a trajectory towards more natural habitat conditions, and our results do not support the hypothesis that gradual destruction of the restored habitat might partly explain weak biological responses. From the perspective of channel evolution, the restorations were still fairly recent, and only long‐term monitoring will tell if the sites will continue on the trajectory to hydromorphological and ecological recovery. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
9.
In the face of rapid environmental and cultural change, long‐term ecological research (LTER) and social‐ecological research (LTSER) are more important than ever. LTER contributes disproportionately to ecology and policy, evidenced by the greater proportion of LTER in higher impact journals and the disproportionate representation of LTER in reports informing policymaking. Historical evidence has played a significant role in restoration projects and it will continue to guide restoration into the future, but its use is often hampered by lack of information, leading to considerable uncertainties. By facilitating the storage and retrieval of historical information, LTSER will prove valuable for future restoration. 相似文献
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11.
Mohamed Tarhouni Walid Ben Hmida Azaiez Ouled Belgacem Mounir Louhaichi Mohamed Neffati 《African Journal of Ecology》2017,55(4):509-517
In dry areas, natural plant communities are mainly affected by climatic stress and human disturbances – overgrazing, ploughing and biomass harvesting – that accelerate their degradation. Management techniques, including creation of national parks (fencing), are needed to conserve natural resources/biodiversity. The long‐term effects of protection on the plant communities should be monitored. This study assessed the results of long‐term protection on the composition and diversity of the natural plant communities of Sidi Toui National Park (southern Tunisia) using the point‐quadrat method and ecological indicators of the ecosystem structure. Comparison of these indicators for the period 1990–2011 inside (fenced) and outside (disturbed) the Park showed that regeneration of natural vegetation increased during the first decade of the fencing period (1990–2001), but declined during the period (2008–2011). After a long period of fencing, plant tufts were bigger and aged, and the ecosystem dynamics decreased. In the absence of animal activities, the hardpan at the soil surface impedes seedling emergence. This suggests that long‐term fencing is not recommended for conserving floral diversity in dryland ecosystems. To ensure and maintain the regeneration of these ecosystems, fencing periods alternating with controlled grazing (by introducing wild herbivores) are recommended. 相似文献
12.
HEIKE HADRYS ANTONIA WARGEL SANDRA GIERE BERND KRAUS BRUNO STREIT 《Molecular ecology resources》2007,7(2):287-289
Odonates (dragonflies and damselflies) are important indicators for monitoring anthropogenic impacts on freshwater ecosystems. We developed a panel of microsatellite loci for the keeled skimmer Orthetrum coerulescens, a libellulid dragonfly inhabiting small streams. By using two different isolation techniques, nine microsatellite loci have been isolated. Screening of 209 individuals resulted in an overall number of 88 alleles, ranging from three to 19 alleles per locus. The observed heterozygosity ranged from 0.37 to 0.83. One locus showed significant deviation from Hardy–Weinberg equilibrium. 相似文献
13.
CHRIS R. SHORTALL ALISON MOORE EMMA SMITH MIKE J. HALL IAN P. WOIWOD RICHARD HARRINGTON 《Insect Conservation and Diversity》2009,2(4):251-260
Abstract. 1. For the first time, long‐term changes in total aerial insect biomass have been estimated for a wide area of Southern Britain. 2. Various indices of biomass were created for standardised samples from four of the Rothamsted Insect Survey 12.2 m tall suction traps for the 30 years from 1973 to 2002. 3. There was a significant decline in total biomass at Hereford but not at three other sites: Rothamsted, Starcross and Wye. 4. For the Hereford samples, many insects were identified at least to order level, some to family or species level. These samples were then used to investigate the taxa involved in the decline in biomass at Hereford. 5. The Hereford samples were dominated by large Diptera, particularly Dilophus febrilis, which showed a significant decline in abundance. 6. Changes in agricultural practice that could have contributed to the observed declines are discussed, as are potential implications for farmland birds, with suggestions for further work to investigate both cause and effect. 相似文献
14.
Valerie Carolin Wentzky Jörg Tittel Christoph Gerald Jäger Karsten Rinke 《Freshwater Biology》2018,63(9):1063-1076
- To counteract the severe consequences of eutrophication on water quality and ecosystem health, nutrient inputs have been reduced in many lakes and reservoirs during the last decades. Contrary to expectations, in some lakes phytoplankton biomass did not decrease in response to oligotrophication (nutrient reduction). The underlying mechanisms preventing a decrease in biomass in these lakes are the subject of ongoing discussion.
- We used a hitherto unpublished long‐term data set ranging from 1961 until 2016 from a German drinking water reservoir (Rappbode Reservoir) to investigate the underlying mechanisms preventing a decrease in biomass. Total phosphorus (TP) concentrations in the Rappbode Reservoir dropped abruptly in 1990 from 0.163 to 0.027 mg/L within three consecutive years, as a result of banning phosphate‐containing detergents. Despite substantial reductions in TP, total annual phytoplankton biomass did not decline in the long‐run, and therefore, the yield of total phytoplankton biomass per unit phosphorus largely increased.
- Regression analysis revealed a positive association between the yield and potentially phagotrophic mixotrophs (R2 = .465, p < .001). We infer that by ingesting bacteria, mixotrophic species were capable of exploiting additional P sources that are not accessible to obligate autotrophic phytoplankton, eventually preventing a decrease in algal biomass after TP reductions.
- Long‐term epilimnetic phosphorus concentrations during the winter mixing period decreased to a greater degree than summer phosphorus concentrations. Apparently, TP losses over the season were less intense. Spring diatom biomass also markedly decreased after oligotrophication. In fact, spring diatom biomass was positively related to the TP loss over the season suggesting diatoms play an important role in P reduction. However, this intraannual P processing was not the primary factor when focusing on the average yearly yield, which remained to be fully explained by mixotrophs.
- Our study demonstrates this ecosystem's ability to compensate for changes in resource availability through changes in phytoplankton community composition and functional strategies. We conclude that an increase in mixotrophy and the ability to make bacterial phosphorus available for phytoplankters were the main factors that allowed the phytoplankton community of the Rappbode Reservoir to adapt to lower nutrient levels without a loss in total biomass.
15.
《Ecohydrology》2017,10(1)
Hydrogeomorphic (HGM) wetland classifications are becoming increasingly common but lack substantial review of assumptions behind those classifications. In this paper, I compare an HGM classification of wetland sites developed by best professional judgment with a classification developed using long‐term hydrologic data over those same sites. Forty‐two wetlands, covering five HGM subclasses, were sampled for over a decade in central Pennsylvania. Using median depth to water as the metric, four groups were identified through cluster analysis (created, riparian depression/slope, and two combinations of headwater/mainstem floodplains). The groundwater‐fed sites (riparian depressions and toe‐of‐slopes) were clearly separated by their more consistent source of water, whereas other slopes and floodplain sites were less clearly defined. Long‐term assessment of hydrology generally supported an HGM classification scheme developed under less stringent conditions and produced by best professional judgment, but improvements in the assessment of drier sites are needed. 相似文献
16.
Ervan Rutishauser Stuart J. Wright Richard Condit Stephen P. Hubbell Stuart J. Davies Helene C. Muller‐Landau 《Global Change Biology》2020,26(3):1485-1498
Tropical forest responses to climate and atmospheric change are critical to the future of the global carbon budget. Recent studies have reported increases in estimated above‐ground biomass (EAGB) stocks, productivity, and mortality in old‐growth tropical forests. These increases could reflect a shift in forest functioning due to global change and/or long‐lasting recovery from past disturbance. We introduce a novel approach to disentangle the relative contributions of these mechanisms by decomposing changes in whole‐plot biomass fluxes into contributions from changes in the distribution of gap‐successional stages and changes in fluxes for a given stage. Using 30 years of forest dynamic data at Barro Colorado Island, Panama, we investigated temporal variation in EAGB fluxes as a function of initial EAGB (EAGBi) in 10 × 10 m quadrats. Productivity and mortality fluxes both increased strongly with initial quadrat EAGB. The distribution of EAGB (and thus EAGBi) across quadrats hardly varied over 30 years (and seven censuses). EAGB fluxes as a function of EAGBi varied largely and significantly among census intervals, with notably higher productivity in 1985–1990 associated with recovery from the 1982–1983 El Niño event. Variation in whole‐plot fluxes among census intervals was explained overwhelmingly by variation in fluxes as a function of EAGBi, with essentially no contribution from changes in EAGBi distributions. The high observed temporal variation in productivity and mortality suggests that this forest is very sensitive to climate variability. There was no consistent long‐term trend in productivity, mortality, or biomass in this forest over 30 years, although the temporal variability in productivity and mortality was so strong that it could well mask a substantial trend. Accurate prediction of future tropical forest carbon budgets will require accounting for disturbance‐recovery dynamics and understanding temporal variability in productivity and mortality. 相似文献
17.
Federica Ragazzola Laura C. Foster Armin U. Form Janina Büscher Thor H. Hansteen Jan Fietzke 《Ecology and evolution》2013,3(10):3436-3446
It is important to understand how marine calcifying organisms may acclimatize to ocean acidification to assess their survival over the coming century. We cultured the cold water coralline algae, Lithothamnion glaciale, under elevated pCO2 (408, 566, 770, and 1024 μatm) for 10 months. The results show that the cell (inter and intra) wall thickness is maintained, but there is a reduction in growth rate (linear extension) at all elevated pCO2. Furthermore a decrease in Mg content at the two highest CO2 treatments was observed. Comparison between our data and that at 3 months from the same long‐term experiment shows that the acclimation differs over time since at 3 months, the samples cultured under high pCO2 showed a reduction in the cell (inter and intra) wall thickness but a maintained growth rate. This suggests a reallocation of the energy budget between 3 and 10 months and highlights the high degree plasticity that is present. This might provide a selective advantage in future high CO2 world. 相似文献
18.
AKIHIRO NAKAMURA CARLA P. CATTERALL CHRIS J. BURWELL ROGER L. KITCHING ALAN P. N. HOUSE 《Insect Conservation and Diversity》2009,2(3):221-231
Abstract. 1. Development of foliage cover and a layer of leaf litter are two factors considered important for the successful recolonisation of soil and litter arthropods during the early stages of rainforest restoration; however, this needs to be tested explicitly. 2. We employed a manipulative field experiment to assess the effects of shading and litter depth on colonisation patterns of soil and litter arthropods in created habitat patches at five replicated sites within pasture adjacent to rainforest remnants on the Maleny plateau of subtropical eastern Australia. 3. Habitat patches were created by adding sterilised mulch at two depths (shallow 3–5 cm, deep 10–15 cm) under three levels of shading (none, 50%, 90%). Responses of arthropods to treatments were analysed at two levels of taxonomic resolution: ‘ordinal‐sorted arthropods’ (all arthropods sorted to order/class) and ant species (Hymenoptera: Formicidae). 4. Shading, at both 50% and 90%, encouraged colonisation by arthropods characteristic of rainforest. Colonisation by pasture‐associated arthropods declined progressively with increased shading. Effects of mulch depth were significant only for rainforest‐associated ant species, which responded positively to shallow mulch within shaded plots. 5. The results confirm that canopy cover is indeed one of the primary attributes influencing colonisation patterns of arthropods in restored vegetation. More widely spaced plantings may facilitate some colonisation by rainforest arthropods. However, in order to suppress invasion by pasture‐associated arthropods, it may be necessary to establish a fully closed canopy. 相似文献
19.
GABOR POZSGAI JOHN BAIRD NICK A. LITTLEWOOD ROBIN J. PAKEMAN MARK R. YOUNG 《Ecological Entomology》2016,41(2):157-167
1. One‐way, directional changes in both plant and animal associations are likely to be occurring as a result of changing climate. Current knowledge of long‐term cycles in insect communities is scarce, and therefore it is difficult to assess whether the observed changes in insect communities are the first part of a long‐term trend or parts of normal cycles. 2. In this study multivariate methods were used to describe the trends in ground beetle (Coleoptera: Carabidae) assemblages over an 18‐year (1994–2011) period at two Scottish sites. In order to have a deeper insight into the underlying processes, both environmental factors and the species driving the detected changes were investigated. 3. In four out of the six sample transects, insect community compositions showed trends rather than fluctuating patterns. Hierarchical cluster analysis also revealed a clear separation, after accounting for sampling location and broad habitat, between early and later years of sampling. Decreasing annual maximum temperatures and increasing precipitation were identified as the main environmental drivers. Although increased rainfall was expected to be beneficial for hygrophilous species, in the transects in this study generalist species increased in dominance. 4. The increasing importance of generalists, in the communities studied here, underlines the vulnerability of the specialist species and urges greater effort in their conservation. Assemblage changes along different trajectories at the sites in the present study could only be tracked using multivariate methods; commonly used diversity indices proved to be unsatisfactory. Therefore, the exclusive use of simple diversity indices should be discouraged and multivariate methods should be preferred in environmental assessments and conservation planning. 相似文献
20.
Land‐cover and climate change are two main drivers of changes in species ranges. Yet, the majority of studies investigating the impacts of global change on biodiversity focus on one global change driver and usually use simulations to project biodiversity responses to future conditions. We conduct an empirical test of the relative and combined effects of land‐cover and climate change on species occurrence changes. Specifically, we examine whether observed local colonization and extinctions of North American birds between 1981–1985 and 2001–2005 are correlated with land‐cover and climate change and whether bird life history and ecological traits explain interspecific variation in observed occurrence changes. We fit logistic regression models to test the impact of physical land‐cover change, changes in net primary productivity, winter precipitation, mean summer temperature, and mean winter temperature on the probability of Ontario breeding bird local colonization and extinction. Models with climate change, land‐cover change, and the combination of these two drivers were the top ranked models of local colonization for 30%, 27%, and 29% of species, respectively. Conversely, models with climate change, land‐cover change, and the combination of these two drivers were the top ranked models of local extinction for 61%, 7%, and 9% of species, respectively. The quantitative impacts of land‐cover and climate change variables also vary among bird species. We then fit linear regression models to test whether the variation in regional colonization and extinction rate could be explained by mean body mass, migratory strategy, and habitat preference of birds. Overall, species traits were weakly correlated with heterogeneity in species occurrence changes. We provide empirical evidence showing that land‐cover change, climate change, and the combination of multiple global change drivers can differentially explain observed species local colonization and extinction. 相似文献