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11.
Recovery of lotic macroinvertebrate communities from disturbance 总被引:7,自引:0,他引:7
J. Bruce Wallace 《Environmental management》1990,14(5):605-620
Ecosystem disturbances produce changes in macrobenthic community structure (abundances, biomass, and production) that persist
for a few weeks to many decades. Examples of disturbances with extremely long-term effects on benthic communities include
contamination by persistent toxic agents, physical changes in habitats, and altered energy inputs. Stream size, retention,
and local geomorphology may ameliorate the influence of disturbances on invertebrates. Disturbances can alter food webs and
may select for favorable genotypes (e.g., insecticidal resistance). Introductions of pesticides into lotic ecosystems, which
do not result in major physical changes within habitats, illustrate several factors that influence invertebrate recovery time
from disturbance. These include: (1) magnitude of original contamination, toxicity, and extent of continued use; (2) spatial
scale of the disturbance; (3) persistence of the pesticide; (4) timing of the contamination in relation to the life history
stages of the organisms; (5) vagility of populations influenced by pesticides; and (6) position within the drainage network.
The ability of macroinvertebrates to recolonize denuded stream habitats may vary greatly depending on regional life histories,
dispersal abilities, and position within the stream network (e.g., headwaters vs larger rivers). Although downstream drift
is the most frequently cited mechanism of invertebrate recolonization following disturbance in middle- and larger-order streams,
evidence is presented that shows aerial recolonization to be potentially important in headwater streams. There is an apparent
stochastic element operating for aerial recolonization, depending on the timing of disturbance and flight periods of various
taxa. Available evidence indicates that recolonization of invertebrate taxa without an aerial adult stage requires longer
periods of time than for those that possess winged, terrestrial adult stages (i.e., most insects). Innovative, manipulative
experiments are needed in order to address recolonization mechanisms of animals inhabiting streams that differ in size, latitude,
disturbance frequency and magnitude, as well as the potential influence of early colonists on successional sequences of species
following disturbance. 相似文献
12.
Development of a bird integrity index: using bird assemblages as indicators of riparian condition 总被引:7,自引:0,他引:7
We describe the development of a bird integrity index (BII) that uses bird assemblage information to assess human impacts
on 13 stream reaches in the Willamette Valley, Oregon, USA. We used bird survey data to test 62 candidate metrics representing
aspects of bird taxonomic richness, tolerance or intolerance to human disturbance, dietary preferences, foraging techniques,
and nesting strategies that were affected positively or negatively by human activities. We evaluated the metric responsiveness
by plotting each one against a measure of site disturbance that included aspects of land use/land cover, road density, riparian
cover, and stream channel and substrate conditions. In addition, we eliminated imprecise and highly correlated (redundant)
metrics, leaving 13 metrics for the final index. Individual metric scores ranged continuously from 0 to 10, and index scores
were weighted to range from 0 to 100. Scores were calibrated using historical species information to set expectations for
the number of species expected under minimally disturbed conditions. Site scores varied from 82 for the least disturbed stream
reach to 8.5 for an urban site. We compared the bird integrity index site scores with the performance of other measures of
biotic response developed during this study: a fish index of biointegrity (IBI) and two benthic macroinvertebrate metrics.
The three assemblages agreed on the general level of disturbance; however, individual sites scored differently depending on
specific indicator response to in-stream or riparian conditions. The bird integrity index appears to be a useful management
and monitoring tool for assessing riparian integrity and communicating the results to the public. Used together with aquatic
indicator response and watershed data, bird assemblage information contributes to a more complete picture of stream condition. 相似文献
13.
Recovery of temperate-stream fish communities from disturbance: A review of case studies and synthesis of theory 总被引:3,自引:0,他引:3
Naomi E. Detenbeck Philip W. DeVore Gerald J. Niemi Ann Lima 《Environmental management》1992,16(1):33-53
To evaluate the relative effect of autecologic factors, site-specific factors, disturbance characteristics, and community
structure on the recovery of temperate-stream fish communities, we reviewed case histories for 49 sites and recorded data
on 411 recovery end points. Most data were derived from studies of low-gradient third- or fourth-order temperate streams located
in forested or agricultural watersheds. Species composition, species richness, and total density all recovered within one
year for over 70% of systems studied. Lotic fish communities were not resilient to press disturbances (e.g., mining, logging,
channelization) in the absence of mitigation efforts (recovery time >5 to >52 yr) and in these cases recovery was limited
by habitat quality. Following pulse disturbances, autecological factors, site-specific factors, and disturbance-specific factors
all affected rates of recovery. Centrarchids and minnows were most resilient to disturbance, while salmonid populations were
least resilient of all families considered. Species within rock-substrate/nest-spawning guilds required significantly longer
time periods to either recolonize or reestablish predisturbance population densities than did species within other reproductive
guilds. Recovery was enhanced by the presence of refugia but was delayed by barriers to migration, especially when source
populations for recolonization were relatively distant. Median population recovery times for systems in which disturbances
occurred during or immediately prior to spawning were significantly less than median recovery times for systems in which disturbances
occurred immediately after spawning. There was little evidence for the influence of biotic interactions on recovery rates. 相似文献
14.
Environmental regulations governing industrial activities in tundra environments stem largely from the expected ecological
effects of the activities. One of the major ecological effects of industrial activities is the surface subsidence associated
with thermokarst, which can result in changes in primary and secondary production. The primary production changes associated
with thermokarst are strongly governed by three ecosystem properties—soil temperature, water regime, and nutrient availability.
Most disturbances set in motion a more-or-less predictable sequence of landscape change related to these properties: soil
warming, thermokarst, surface flooding, accelerated organic matter decomposition, and increased nutrient availability. The
warmed soil and the enhanced nutrient availability typically lead to increased annual primary production, increased dominance
by graminoids, and reduced plant species diversity. These vegetational changes may in turn potentially enhance secondary production,
but in general these second-level responses have yet to be quantified. More information is needed about the food-chain effects
of tundra landscape disturbances before regulators can make well-informed predictions of impacts or plan useful habitat rehabilitation. 相似文献
15.
Bogaert J Salvador-Van Eysenrode D Impens I Van Hecke P 《Environmental management》2001,27(4):493-500
A method is proposed to quantify disturbance impact on isolated habitats. For every landscape patch, the breakpoint distance,
defined as the penetration distance for which equality of interior and edge habitat is observed, can be calculated. Disturbance
with equal impact at all patch sides is assumed. Effects of patch compactness, size, convolution, and perforation are discussed.
The potential use of the measure for nature reserve design is discussed. The breakpoint distance follows the reserve design
guidelines for individual patches, based on island biogeography and is consistent with the form and function principle. A
large breakpoint distance is preferred for natural habitats. Small size, small compactness, intense convolution, and the occurrence
of many gaps depress the breakpoint distance. 相似文献
16.
Marine biodiversity is generally higher in benthic than in pelagic systems, and in coastal than in open sea systems. Sediments are the most human-impacted domain and therefore represent the target zone for both the study and actions needed for the preservation of biodiversity. Losses of marine diversity, higher (or simply more evident) in coastal areas, are generally the result of conflicting uses of coastal habitats. Large difficulties arise from the analysis and evaluation of the actual biodiversity, especially when different environments are compared, as often studies on biodiversity are dependent upon the distribution of the specialists. On the other hand, losses of marine biodiversity might be underestimated, due to the limited knowledge of the ecosystems' functioning, of the species inhabiting various habitats and of the still limited capacity to assess microbial biodiversity, which represents the largest fraction of the global marine biodiversity. Finally, claimed losses of biodiversity might be just apparent, as the sea floor is a bank of resting stages of various plankton species that are likely to spend even decades in the sediment before reactivating and inducing unattended blooms in the water column. The Mediterranean Sea displays high species diversity, but might reach the highest values in terms of adaptive strategies and functional diversity. Moreover, the Mediterranean Sea represents also a key area for the study of the relative influences of the natural and anthropogenic changes on biodiversity and its consequences on ecosystem functioning. Habitat destruction, over-fishing, contaminants, eutrophication, introduction of alien species, and climate changes are producing increasingly evident changes in community structure and biodiversity of this warm and miniature ocean. We summarized the main effects of different disruptive agents on the marine biodiversity of the Mediterranean Sea, with special attention on the biodiversity relevance in ecosystem functioning and possible implications in bio-geochemical cycles. The present overview aims at focusing and synthesizing the most important factors potentially affecting the interactions between biodiversity and ecosystem functioning in the Mediterranean in order to better define possible strategies of conservation and eco-management. 相似文献
17.
We sampled 240 wadeable streams across Wisconsin for different forms of phosphorus and nitrogen, and assemblages of macroinvertebrates
and fish to (1) examine how macroinvertebrate and fish measures correlated with the nutrients; (2) quantify relationships
between key biological measures and nutrient forms to identify potential threshold levels of nutrients to support nutrient
criteria development; and (3) evaluate the importance of nutrients in influencing biological assemblages relative to other
physicochemical factors at different spatial scales. Twenty-three of the 35 fish and 18 of the 26 macroinvertebrate measures
significantly correlated (P < 0.05) with at least one nutrient measure. Percentages of carnivorous, intolerant, and omnivorous fishes, index of biotic
integrity, and salmonid abundance were fish measures correlated with the most nutrient measures and had the highest correlation
coefficients. Percentages of Ephemeroptera–Plecoptera–Trichoptera individuals and taxa, Hilsenhoff biotic index, and mean
tolerance value were macroinvertebrate measures that most strongly correlated with the most nutrient measures. Selected biological
measures showed clear trends toward degradation as concentrations of phosphorus and nitrogen increased, and some measures
showed clear thresholds where biological measures changed drastically with small changes in nutrient concentrations. Our selected
environmental factors explained 54% of the variation in the fish assemblages. Of this explained variance, 46% was attributed
to catchment and instream habitat, 15% to nutrients, 3% to other water quality measures, and 36% to the interactions among
all the environmental variables. Selected environmental factors explained 53% of the variation in macroinvertebrate assemblages.
Of this explained variance, 42% was attributed to catchment and instream habitat, 22% to nutrients, 5% to other water quality
measures, and 32% to the interactions among all the environmental variables. 相似文献
18.
Rosenbloom T 《Journal of Safety Research》2006,37(2):207-212
INTRODUCTION: Through spontaneous driving observations, this study sought to examine the impact of using a hands-free cell phone while driving on speed and safe gap keeping behaviors. The study also examined the association between the measure of disturbance created by using a cell phone and the driver's awareness of the disturbance. METHOD: Twenty-three male adults were observed while driving for an hour and a half each; drivers were unaware of being observed. During the session, each of the participants received a phone call, initiated by an associate of the observer. The experiment was divided into two periods during which the experimental parameters were monitored: 10 minutes during conversation on a cell phone and 10 minutes of non-conversation on a hands-free cell phone. After the experiment, the driver was questioned concerning the extent to which his/her driving was disturbed by the cell phone conversation. RESULTS: T-test for matched samples revealed that the gaps between the drivers' cars and those in front of them diminished when drivers were engaged in the cell phone conversations. Repeated measures ANOVA revealed that drivers that had short conversations did not change their speed, while drivers who were engaged in long (over 16 minutes) conversations drove faster. No effect of drivers' awareness toward cell phone-related disturbance on actual driving behavior monitored in the present study was found. 相似文献
19.
Victoria?SorokerEmail author Dennis?R.?Nelson Ornit?Bahar Saadia?Reneh Sarah?Yablonski Eric?Palevsky 《Chemoecology》2003,13(4):163-168
Summary. Broad mite, Polyphagotarsonemus latus (Acari:
Tarsonemidae) exhibits a specific phoretic relationship with
whiteflies. Under field conditions most broad mites, caught
in sticky traps, are attached to whiteflies. Under laboratory
conditions, attachment occurs equally well in the dark and
light. Mites do not differentiate between the sexes of their
phoretic host Bemisia tabaci. However, mite attachment to
B. tabaci is greatly diminished by washing the host with
various organic solvents, chloroform in particular. The
effect of whitefly waxy particles on broad mite behavior was
studied using wax from the whitefly Aleyrodes singularis
and from the mealybug Planococcus citri. Broad mites were
not only attracted specifically to the A. singularis waxy
particles-treated leaf areas but were also attached to leaf
trichomes in this area. The results of this study suggests the
importance of olfactory cues from the whitefly waxy particles
in the recognition process of the phoretic host and/or
the induction of the attachment behavior to whitefly legs or
leaf trichomes. 相似文献
20.
Summary. In amphibians and fishes, evidence is increasing that chemical cues from injured conspecifics can play a role in the chemical
labelling and learned recognition of unfamiliar predators. In this laboratory study, we tested the prediction that prior chemical
exposure to a non-native predator feeding on conspecific tadpoles will subsequently allow tadpoles of the common toad (Bufo bufo) to recognize the chemical cues specifically released by this starved predator. Furthermore, we investigated the vulnerability
of this chemically-mediated process to herbicide contamination. With these aims in view, groups of tadpoles were kept either
unexposed or exposed for ten days to chemical cues from Turkish crayfish (Astacus leptodactylus) previously fed on tadpoles, both in uncontaminated water and in the presence of four sublethal concentrations of amitrole
(0.01, 0.1, 1 and 10 mg.l−1). We then assessed the effects of the six conditioning treatments on general activity and behavioural response to chemical
cues from starved crayfish. Larval treatments did not affect the general activity of the tadpoles. By contrast, the treatments
had significant effects on the behavioural response to the test solution prepared form starved crayfish. The only tadpoles
to show an antipredator behavioural response to the chemical stimulation from starved crayfish belonged to the groups derived
from chemical exposure to tadpole-fed crayfish in uncontaminated water and in contaminated water with the lowest concentration
of amitrole (0.01 mg.l−1). Conversely, this chemical stimulation produced no behavioural change in the control group or in the groups derived from
exposure to tadpole-fed crayfish in contaminated water containing 0.1, 1 and 10 mg.l−1 of amitrole. This study demonstrates that chemical cues released during the predator’s feeding activity can subsequently
be used by common toad tadpoles in the recognition of an unfamiliar predator. In addition, our results show that the presence
of sublethal amitrole concentrations can impair this recognition process. Such a pesticide effect might be especially detrimental
for amphibian populations threatened by invasive predators. 相似文献