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1.
Anegg U Dietmaier G Maier A Tomaselli F Gabor S Kallus KW Smolle-Jüttner FM 《Life sciences》2002,70(23):2721-2734
The majority of injuries in scuba-divers are attributable to inappropriate behavior under stressful diving conditions, predominantly involving panic reactions emerging from elevated levels of anxiety. Divers with an elevated level of anxiety and poor coping are at higher risk of developing panic reactions than those possessing more adequate stress-coping-mechanisms. In the comparison of two extreme groups of seven divers each with opposite stress coping strategies, prolactin was found to be a hormonal marker with a significant increase in the sub-group of the stress-controllers. This hormonal response was observed in a recreational and a stressful dive, and in the latter with a more distinct elevation. Along with the self-reported emotional conditions under immersion, these data suggest that an increased prolactin level reflects a state of elevated physical and mental activation and vigilance. Facing a stressful situation subjects with more emotional concern and the tendency to surrender react by "blunted responses" and show significantly lower elevations of the prolactin levels in contrast to subjects with the very opposite psychological features. The other observed somatic parameters (epinephrine, norepinephrine) showed significant increases during and after dives (with the exception of saliva cortisol), however without any significant group difference. 相似文献
2.
A recent study ( White et al. 2008 ) claimed that fishery profits will often be higher with management that employs no‐take marine reserves than conventional fisheries management alone. However, this conclusion was based on the erroneous assumption that all landed fish have equal value regardless of size, and questionable assumptions regarding density‐dependence. Examination of an age‐structured version of the White et al. (2008) model demonstrates that their results are not robust to these assumptions. Models with more realistic assumptions generally do not indicate increased fishery yield or profits from marine reserves except for overfished stocks. 相似文献
3.
J. E. Cinner 《Coral reefs (Online)》2007,26(4):1035-1045
Coral reef conservation strategies such as marine protected areas have met limited success in many developing countries. Some
researchers attribute part of these shortcomings to inadequate attention to the social context of conserving marine resources.
To gain insights into applying Western conservation theory more successfully in the socioeconomic context of developing countries,
this study examines how long-enduring, customary reef closures appear to reflect local socioeconomic conditions in two Papua
New Guinean communities. Attributes of the customary management (including size, shape, permanence, and gear restrictions)
are examined in relation to prevailing socioeconomic conditions (including resource users’ ability to switch gears, fishing
grounds, and occupations). Customary closures in the two communities appear to reflect local socioeconomic circumstances in
three ways. First, in situations where people can readily switch between occupations, full closures are acceptable with periodic
harvests to benefit from the closure. In comparison, communities with high dependence on the marine resources are more conducive
to employing strategies that restrict certain gear types while still allowing others. Second, where there is multiple clan
and family spatial ownership of resources, the communities have one closure per clan/family; one large no-take area would
have disproportionate affect on those compared to the rest of the community. In contrast, communities that have joint ownership
can establish one large closure as long as there are other areas available to harvest. Third, historical and trade relationships
with neighboring communities can influence regulations by creating the need for occasional harvests to provide fish for feasts.
This study further demonstrates the importance of understanding the socioeconomic context of factors such as community governance
and levels of dependence for the conservation of marine resources. 相似文献
4.
S. E. McNeill 《Biodiversity and Conservation》1994,3(7):586-605
Recently there has been increased interest in the use of Marine Protected Areas (MPAs) as tools for the conservation of marine habitats and species. This has resulted in the declaration of many MPAs around the world. Despite this activity there have been few tests of hypotheses about the design criteria for selection and management of these areas, resulting in a haphazard and ad hoc selection of protected areas, with conflicting and inconsistent terminology and objectives. The application of appropriately tested scientific information to the design of MPAs will increase the likelihood of success in the future.To 1st January 1992, 267 MPAs had been declared in Australia, covering a total area of ca 400 019 km2. The history of their declaration has been sporadic and uneven. Conflicts over State and Federal legislation and, within states, conflicts over jurisdiction among agencies caused by overlapping responsibilities, have at times slowed the declaration of MPAs. In this paper, the history of MPAs in Australia is used as a case study to discuss the problems, both biological and administrative, of declaring MPAs. 相似文献
5.
The Mexican Government decreed Chinchorro Bank reef as a Biosphere Reserve in 1996. The aim of this study was to evaluate
the spatial and size-frequency distribution of Acropora spp. in order to provide further knowledge and tools to enhance management. A field survey was conducted, within six regions,
to locate and measure Acropora patches in the reef lagoon. Density, colony size and living tissue cover of Acropora colonies were evaluated using the line-intercept transect technique, combining direct observations and video transects. The
results showed that Acropora spp. was preferentially distributed in the southern regions; where cover and density were high. Based on these results and
considering that Acropora spp. produces landscape heterogeneity, which in turn generates shelter for other species, including some of considerable
economic importance, then at least the South East region should be considered as a key area for Acropora species conservation, and should be included in the Chinchorro Bank management plan. 相似文献
6.
Stefano Scalercio Roberto Pizzolotto Pietro Brandmayr 《Biodiversity and Conservation》2007,16(12):3463-3479
This paper is an attempt to outline a protocol for animal diversity census and evaluation aimed for areas in view of landscape
planning of territories of hundred square kilometres and more, that may work utilising different faunal groups and be anyway
useful at various scales. Many papers are addressed to elaborate tools for landscape planning starting from biodiversity evaluation
and butterflies are often utilised because of their sensitivity to landscape modifications. In this work, the biodiversity
evaluation has been performed using three hierarchically linked landscape units at micro-, meso- and macroscale. Being species
diversity values often inadequate to define the conservation interest of a landscape portion, more importance has been given
to which species compose the species assemblages. A community vulnerability Index was coded and used for evaluating potential
consequences of human disturbance on butterfly assemblages. Forty-four year samples were gained by visual census in the Sila
Greca, Southern Italy, on an area of approximately 520 square kilometres. During 5 years work, 2,535 specimens and 94 species
were recorded, equal to 75.8% of the whole Calabrian fauna. Four vulnerability levels have been established and used for mapping
butterfly assemblage vulnerability in the area, starting from a vegetation map. Species richness was found somewhat contradictory
at micro-scale, where the community vulnerability Index gives a sounder approach. S diversity gives a more reliable picture of naturalness at meso-scale, a level we identified with the “ecotope”. At this more
“geomorphic” scale level, biological functions reflected by butterfly assemblages revealed to be clearly linked to seral processes.
Similarity analysis results show that the ecotope species richness, here called “eta-diversity”, could be an useful measure
of zoological landscape (faunation) potentialities. 相似文献
7.
Marco Milazzo Fabio Badalamenti Renato Chemello 《Journal of experimental marine biology and ecology》2004,299(1):51-62
Seagrasses worldwide are noted for suffering from mechanical damage caused by boat anchoring. This is particularly so in sites highly frequented by boaters (marine protected areas or coastal urbanised areas). In the last decades, different strategies have been put into practice to reduce such impacts on seagrasses (i.e. by anchoring bans or by deploying boat moorings). More recently, in consideration that few marine protected area (MPA) management bodies or local administrations have the resources to enforce their anchorage regulations, the self-regulatory approach based on education and information of boaters has been preferred in several cases. At present, however, very little is known on the correct anchoring practices to ensure the safeguarding of seagrasses. The aim of the present study was to experimentally quantify in the field the damage caused to Posidonia oceanica shoot density by anchoring. A multifactorial experiment was designed to test whether the damage is dependent on (1) different anchor types (Hall, Danforth and Folding grapnel), (2) the use of a chain vs. a rope, (3) the three anchoring stages (anchor fall, dragging/lock-in and weighing), and finally (4) whether the pattern is consistent among different locations of the meadow.As expected, the three anchor types employed in the present study differed in the levels of damage inflicted on the P. oceanica meadows of the Ustica Island MPA. In particular, the use of the Hall type anchor seems to be preferable to minimise this impact in comparison with the other two anchor types. Moreover, the effect on the meadow of the three anchor types is greatly dependent on the anchoring stage. These results confirm that the weighing stage is the critical stage of the anchoring process. The number of damaged shoots of P. oceanica was not affected by the presence of the chain. These patterns were consistent between locations.In the long term, even anchoring on P. oceanica by small boats using low-impact anchors may potentially have detrimental consequences. For this reason, we suggest that in vulnerable sites, it is preferable to implement an educational program based on information of boaters on correct anchoring practices and anchor typology to use, rather than adopting strong restrictions to boat anchoring or deploying mooring buoys. Although the use of these management strategies is still recommended in the case of anchorage frequented by bigger vessels using heavier anchors and chains. 相似文献
8.
J.C.A. Joordens F.P. Wesselingh J. de Vos H.B. Vonhof D. Kroon 《Journal of human evolution》2009,(6):656-671
Knowledge about dietary niche is key to understanding hominin evolution, since diet influences body proportions, brain size, cognition, and habitat preference. In this study we provide ecological context for the current debate on modernity (or not) of aquatic resource exploitation by hominins. We use the Homo erectus site of Trinil as a case study to investigate how research questions on possible dietary relevance of aquatic environments can be addressed. Faunal and geochemical analysis of aquatic fossils from Trinil Hauptknochenschicht (HK) fauna demonstrate that Trinil at ∼1.5 Ma contained near-coastal rivers, lakes, swamp forests, lagoons, and marshes with minor marine influence, laterally grading into grasslands. Trinil HK environments yielded at least eleven edible mollusc species and four edible fish species that could be procured with no or minimal technology. We demonstrate that, from an ecological point of view, the default assumption should be that omnivorous hominins in coastal habitats with catchable aquatic fauna could have consumed aquatic resources. The hypothesis of aquatic exploitation can be tested with taphonomic analysis of aquatic fossils associated with hominin fossils. We show that midden-like characteristics of large bivalve shell assemblages containing Pseudodon and Elongaria from Trinil HK indicate deliberate collection by a selective agent, possibly hominin. 相似文献
9.
Our knowledge of suitable criteria to determine rarity in most marine invertebrates is lacking, thus hindering targeted impact
studies, long-term monitoring programs, and associated conservation strategies. Standardized definitions of rarity are required
to enable comparisons of different assemblages and taxa. Gaston (Rarity, Chapman and Hall, Melbourne, 1994) has recommended that rare species are defined as the lowest quartile of species in the assemblage. In this study, the 25%
‘cut-off’ was applied to intertidal macro-molluscs along the Illawarra Coast, Australia from 200 surveys of 13 reefs, using
three measures of population structure; (1) local abundance (numerical rarity); (2) number of locations (spatial rarity) and;
(3) percent of surveys (temporal rarity). Rare species were consequently defined as those species with no more than; (1) a
local abundance of two individuals; (2) a regional occurrence at two reefs and/or; (3) a temporal occurrence in 2% of all
surveys. These cut-off values increased when only intertidal specialists were analysed. Using a combination of all three measures,
62 species (42%) were classified as regionally rare, but only four of these were true intertidal specialists. Most species
were rare by only one or two definitions of rarity; illustrating the importance of considering multiple measures of rarity
and the need to design specifically targeted survey methods for future monitoring. Many species that are rare by all three
definitions are likely to be temporary immigrants, as subtidal species were significantly more likely to be classified as
rare. Clearly many factors can influence the rarity of marine invertebrates on intertidal reefs, and these must all be considered
to set appropriate conservation priorities. 相似文献
10.
During 2005 monthly samples of the solitary ascidian Herdmania momus were collected along the Mediterranean and Red Sea coasts of Israel, in order to investigate possible differences in life
history strategies of the two populations. The samples were preserved, dissected, and measurements were made of length, total
weight, gonad weight, oocyte diameter and the occurrence of symbionts was recorded. Additionally, field surveys showed that
in the Mediterranean H. momus exclusively inhabit artificial substrates, and are common at greater depths than in Eilat (Red Sea). Individuals of H. momus in Eilat reproduced year round. Although individuals from the Mediterranean were significantly larger than individuals collected
in Eilat their gonad indices and oocyte diameter measurements indicate that they have a short reproductive season. Copepods
were found in 50% of the samples from both sites, while a pontoniine shrimp was found in 14% of the samples from Eilat only.
The marked differences between the native vs. non-indigenous populations of H. momus are attributed to differential food availability, water temperature, currents and wave exposure. The increasing evidence
of negative effects of non-indigenous ascidians on natural fauna from other regions in the world emphasizes the need for additional
research regarding the ecology of ascidians along the coasts of Israel. 相似文献
11.
A holistic methodological procedure to assess estuarine vulnerability within a spatio-temporal framework is presented. This approach quantifies the vulnerability of estuaries to point-source pollution considering the physical processes, the ecological features, and the social aspects related to the existing estuarine ecosystem services. Estuarine vulnerability is referred to those characteristics of an estuarine ecosystem that describe its potential to be harmed. Thus, vulnerability is presented as a combination of four parameters: Tidal Zoning (TZ), State of Conservation (SC), Susceptibility (SU), and Stratification (ST). TZ differs between intertidal and subtidal zones. SC is determined as a combination of Naturalness (NA) and Ecological Value (EV). NA is defined as the absence of physical anthropogenic modifications, and EV is described as the presence of singular flora and fauna. While SU is related to the flushing or cleaning capacity, ST accounts for the location of mixed, partially mixed/stratified and stratified areas in the estuary. Subsequently, categories, thresholds and assessment criteria for every parameter, and a composite index to integrate all of them, namely the Estuarine Vulnerability Index (EVI), are presented. EVI has been applied to the Suances Estuary (N Spain) to find out the optimal locations for hypothetical point discharges. The results obtained for the Suances Estuary confirm the suitability of the proposed methodology and its conceptual approach as a comprehensive and practical management tool to quantify and prioritize estuarine areas receiving point-source pollution. 相似文献
12.
Mary A. Young Rikk G. Kvitek Corey D. Garza Roger T. Hanlon 《Journal of experimental marine biology and ecology》2011,407(2):226-233
The California squid fishery is concentrated largely on nearshore squid spawning aggregations. Because of this practice a central concern for sustainable squid fisheries in California is to determine whether reproductive activities and subsequent egg laying occur at rates that are sufficient to support harvestable populations of this sub-annual species. Using high-resolution data collected via acoustic mapping methodology, we estimated a 99% decrease in egg mops abundance from 2005 to 2007. Sidescan sonar images from detailed benthic mapping suggest that although squids prefer a sandy substrate as their primary egg mop habitat, the depths across which egg mops were distributed differed significantly between surveys and spatial distribution of egg mops varied across years on this large spawning ground. Our results suggest that sidescan sonar surveys could serve as an important tool used to aid sustainable management of the California market squid fishery through the monitoring, designation and adaptive management of seasonally variable no-take spawning zones and can help in developing stock assessments of this commercially important species. 相似文献
13.
The European Water Framework Directive (WFD) (2000/60/EC) requires assessing the ecological quality status of water bodies, and gives great importance to the biological components of the ecosystem. Within this framework, a multimetric, fuzzy-based index for the evaluation of environmental quality (FINE: fuzzy index of ecosystem integrity) has been developed using data from several Italian coastal lagoons, gathered with seasonal frequency at diverse sites in each lagoon. The rationale of FINE is that certain attributes, selected on the basis of established principles of benthic ecology, are fundamental for lagoon ecosystem function. FINE is composed of seven ecosystem attributes (variables) each of which have ecological relevance for lagoon ecosystems. Individually, all these attributes are themselves useful indices of environmental conditions. However, the combination of these attributes into a single fuzzy index, provides a more robust, overall index of the response of the natural communities to environmental perturbations and avoids misleading or ambiguous results. Each variable is not represented by a single numerical value, but by several categories that describe its properties: in the present model we considered a total of seven variables: two with four modalities (low–medium–high–very high), one with three (low–medium–high) and three with two (low–high), plus a qualitative variable (yes–no), that altogether generate 768 rules. FINE is a low-cost, flexible and robust routine index of lagoon ecosystem impairment and could be of particular benefit to environmental managers and policymakers who require tools capable of expressing the degree of degradation or environmental quality of different lagoon habitats. For its relative simplicity in the application, FINE could be a good candidate to assess the environmental quality of Mediterranean transitional ecosystems. Guest editors: A. Razinkovas, Z. R. Gasiūnaitė, J. M. Zaldivar & P. Viaroli European Lagoons and their Watersheds: Function and Biodiversity 相似文献
14.
Developing biological indicators from diverse data: The Potomac Basin-wide Index of Benthic Integrity (B-IBI) 总被引:3,自引:0,他引:3
A Basin-wide Index of Benthic Integrity (B-IBI) was developed to uniformly assess aquatic ecosystem health of non-tidal, wadeable streams in the multi-jurisdictional Potomac River basin (US). Multiple datasets were merged and used to identify stream classes and discriminating biological metrics. The index (aggregated metric scores) accurately identified 95% of impaired sites. A jackknife cross-validation procedure confirmed the accuracy of the B-IBI. B-IBI assessments generally compare favorably to basin states’ assessments derived from the same data. A habitat quality matrix which includes an indicator of anthropogenic alterations and disturbances is recommended. The Potomac B-IBI is more useful than existing state-specific indexes for stream health comparisons across jurisdictional boundaries and basin-wide. The Potomac B-IBI can improve understanding of water quality issues in the basin and enhance the abilities of water quality managers to make well-informed decisions concerning the basin's non-tidal waters. 相似文献
15.
Spatial and temporal deforestation dynamics in protected and unprotected dry forests: a case study from Myanmar (Burma) 总被引:1,自引:0,他引:1
Melissa Songer Myint Aung Briony Senior Ruth DeFries Peter Leimgruber 《Biodiversity and Conservation》2009,18(4):1001-1018
Tropical dry forests are more threatened, less protected and especially susceptible to deforestation. However, most deforestation
research focuses on tropical rain forests. We analyzed spatial and temporal changes in land cover from 1972 through 2005 at
Chatthin Wildlife Sanctuary (CWS), a tropical dry forest in Myanmar (Burma). CWS is one of the largest protected patches of
tropical dry forest in Southeast Asia and supports over half the remaining wild population of the endangered Eld’s deer. Between
1973 and 2005, 62% of forest was lost at an annual rate of 1.86% in the area, while forest loss inside CWS was only 16% (0.45%
annually). Based on trends found during our study period, dry forests outside CWS would not persist beyond 2019, while forests
inside CWS would persist for at least another 100 years. Analysis of temporal deforestation patterns indicates the highest
rate of loss occurred between 1992 and 2001. Conversion to agriculture, shifting agriculture, and flooding from a hydro-electric
development were the main deforestation drivers. Fragmentation was also severe, halving the area of suitable Eld’s deer habitat
between 1973 and 2001, and increasing its isolation. CWS protection efforts were effective in reducing deforestation rates,
although deforestation effects extended up to 2 km into the sanctuary. Establishing new protected areas for dry forests and
finding ways to mitigate human impacts on existing forests are both needed to protect remaining dry forests and the species
they support. 相似文献
16.
The phylogenetic relationships of the diving-beetle (Dytiscidae) subfamily Copelatinae are not well known. Some authors postulated
a sister-group relationship between Copelatus Erichson and the remaining Dytiscidae, relying mainly on the absence of a mandibular channel in Copelatus. Other authors suggested a more derived position of the genus. Larval characters have been underutilized in phylogenetic
studies, mainly because the larvae of many taxa within the family and, in particular, within Copelatinae are unknown. A comprehensive
approach aimed to study the phylogenetic placement of a member of this subfamily based on larval characters has not been produced
so far. In this study, the phylogenetic relationships of Copelatus are explored based on a cladistic analysis of 24 taxa and 120 chaetotaxic and morphological characters from larvae. For this
purpose, larvae of Copelatus longicornis Sharp are described and illustrated in detail for the first time, with particular emphasis on morphometry and chaetotaxy,
with the latter being unexplored until now. The results support a derived position of Copelatus within Dytiscidae, with a sister-group relationship between this genus and a clade formed by the subfamilies Lancetinae,
Coptotominae, Laccophilinae, Colymbetinae, Matinae, and Dytiscinae, and part of Agabinae. No evidence was found for a sister-group
relationship between Copelatus and the remaining Dytiscidae so that the absence of a mandibular channel in this genus is likely a reduction. Copelatus is supported by three apomorphies within Dytiscidae: mandibular channel absent, internal margin of the stipes with three
robust spinulae, and seta MX8 inserted subapically on the galea.
Handling editor: K. Martens 相似文献
17.
R. T. Graham R. Carcamo K. L. Rhodes C. M. Roberts N. Requena 《Coral reefs (Online)》2008,27(2):311-319
Scientific information on reef fish spawning aggregation fisheries is sparse in light of numerous regional declines and extirpations
from overexploitation. Fisher interviews of the small-scale commercial mutton snapper (Lutjanus analis) spawning aggregation fishery at Gladden Spit, Belize, suggests a historic decadal decline. The reported trend is supported
by analysis of inter-seasonal catch and effort and yield (2000–2002) that reveals a 59% decline in catch per unit effort (CPUE)
and a 22% decrease in mean landings per boat. Declining population-level trends are also supported by a significant decrease
in inter-annual median lengths of mutton snappers (2000–2006). These findings demonstrate the need for additional life history
information that includes length-associated age and details on growth to provide clearer support of the effects on, and responses
by, populations following fishing. In view of the historical changes to mutton snapper CPUE and landings at Gladden Spit and
the fishery-associated declines in fish spawning aggregations observed globally, a precautionary approach to spawning aggregation
management is warranted that provides full protection from fishing to enhance population persistence. The findings also highlight
the need for substantially greater enforcement and long-term fisheries monitoring under a comprehensive regional management
strategy. 相似文献
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Zemah-Shamir Ziv Mourier Johann Ilany Amiyaal Bigal Eyal Scheinin Aviad Tchernov Dan 《Environmental Biology of Fishes》2022,105(5):623-634
Environmental Biology of Fishes - Social and non-social animals can aggregate at a specific site for various reasons such as reproduction, feeding, or other synchronized patterns of movements.... 相似文献