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31.
Dynamics in the global protected-area estate since 2004 总被引:1,自引:0,他引:1
Edward Lewis Brian MacSharry Diego Juffe-Bignoli Nyeema Harris Georgina Burrows Naomi Kingston Neil D. Burgess 《Conservation biology》2019,33(3):570-579
Nations of the world have committed to a number of goals and targets to address global environmental challenges. Protected areas have for centuries been a key strategy in conservation and play a major role in addressing current challenges. The most important tool used to track progress on protected-area commitments is the World Database on Protected Areas (WDPA). Periodic assessments of the world's protected-area estate show steady growth over the last 2 decades. However, the current method, which uses the latest version of the WDPA, does not show the true dynamic nature of protected areas over time and does not provide information on sites removed from the WDPA. In reality, this method can only show growth or remain stable. We used GIS tools in an approach to assess protected-area change over time based on 12 temporally distinct versions of the WDPA that quantify area added and removed from the WDPA annually from 2004 to 2016. Both the narrative of continual growth of protected area and the counter-narrative of protected area removal were overly simplistic. The former because growth was almost entirely in the marine realm and the latter because some areas removed were reprotected in later years. On average 2.5 million km2 was added to the WDPA annually and 1.1 million km2 was removed. Reasons for the inclusion and removal of protected areas in the WDPA database were in part due to data-quality issues but also to on-the-ground changes. To meet the 17% protected-area component of Aichi Biodiversity Target 11 by 2020, which stood at 14.7% in 2016, either the rate of protected-area removal must decrease or the rate of protected-area designation and addition to the WDPA must increase. 相似文献
32.
Imen Rabeh Khaoula Telahigue Safa Bejaoui Tarek Hajji Lassaad Chouba M’hamed EL Cafsi 《Chemistry and Ecology》2019,35(3):204-218
Mercury (Hg) is a ubiquitous and a major environmental metal pollutant in the aquatic ecosystem. The present study was performed to evaluate the effect of mercury graded doses exposure on oxidative stress, redox status, metallothionein levels and genotoxicity in the intestine of sea cucumber Holothuria forskali. Specimens were exposed for 96?h to three concentrations of Hg (40, 80 and 160?µg/L). Exposure of H. forskali to Hg promoted oxidative stress with an increase in malondialdehyde (MDA), protein carbonyl (PCO) and advanced oxidation protein products (AOPP) levels. An increase of glutathione (GSH), vitamin C (ViteC) and non-protein thiols (NPSH) contents was also observed. Additionally, antioxidant activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) increased especially with the highest doses of Hg indicating a great defense of the antioxidant system. Our investigation revealed an increase in total Metallothionein (MT) content which was more pronounced at the sharpest concentrations of Hg. A significant decline of AChE activity was also observed. In the intestine of Hg-treated H. forskali genotoxicity was confirmed by DNA degradation. 相似文献
33.
J. M. Harris 《Marine Biology》1993,116(4):615-629
Direct observation by scanning electron microscopy indicates that the presence of bacteria (epimural and unattached) in the hindguts of Crustacea is widespread, occurring across taxa (two infraorders, i.e., Brachyura and Thalassinidae, nine genera, 16 species), feeding types (detritivores, scavengers and carnivores), habitats (mangroves, saltmarshes, sand/mudflats) and continents (North America, South Africa, Australia). Crustacean hindguts clearly represent suitable environments for colonization by micro-organisms, despite the lack of specialized structures or modifications of the gut to facilitate this. Mats of closely-packed epimural rods and scattered epimural rods were the most common types of bacteria observed in the guts of the Crustacea examined, although unattached rods and scattered epimural cocci occurred in some species. There were, however, taxon-dependent differences in colonization characteristics of hindgut bacteria, possibly related to differences in gut lining. Abundance of hindgut microflora was unrelated to the host's taxon, habitat or geographical locality, but appeared to be affected by the feeding habits of the animal. Mats of epimural rods were associated exclusively with detritivores, while cocci were only observed in the hindguts of scavengers and carnivores. Moreover, extensive colonization by epimural rod bacteria (covering >50% of the hindgut lining) was observed in detritivores only, while carnivores harboured few or no rod bacteria. The detritivore hindgut appears to provide a better environment for microbial habitation than does that of carnivorous crustaceans. In all cases the rod bacteria were monocultures of morphologically identical bacteria and were remarkably similar among crustacean species. The potential significance of prolific microbial colonization in the hindguts of crustaceans deserves consideration.Communicated by O. Kinne, Oldendorf/Luhe 相似文献
34.
Tara R. Harris 《Behavioral ecology and sociobiology》2006,61(2):317-329
In theory, between-group contest (BGC) competition for food can greatly influence female social relationships and reproductive success in primates, but few studies have investigated whether such effects occur and, if so, under what ecological conditions. There is evidence that adult male black and white colobus monkeys (Colobus guereza, “guerezas”) defend the food their mates need against other groups, suggesting that BGC competition is important in this species. Using data on feeding, ranging, vegetation patterns, and intergroup encounters between six neighboring guereza groups, I provide evidence that the highly folivorous guerezas at Kanyawara, Kibale National Park, Uganda, engaged in BGC competition over unevenly dispersed, relatively high-quality feeding areas or “core areas”. Intergroup aggression was common, and groups’ home ranges overlapped. Groups were more likely to initiate high-level aggression if they encountered another group within or near their core area, and groups that initiated and won encounters often fed in the same areas in which losing groups had fed. Guerezas fed selectively on species with contagious (clumped) distributions and concentrated their feeding efforts in areas of the forest that contained the most food (core areas). Groups could be ranked in a linear dominance hierarchy, and group rank number was inversely related to the quantity and quality of food in groups’ core areas. This study not only provides good evidence that BGC competition occurs in primates but it also reinforces the idea that folivore food resources may be worth defending. 相似文献
35.
Jody Berman Larry Harris Walter Lambert Melanie Buttrick Michael Dufresne 《Conservation biology》1992,6(3):435-441
Introduced species are common members of estuarine communities where their role as competitors and predators is of concern, This paper examines the invasion of Gulf of Maine benthic habitats by the ecologically similar alien invertebrates Styela clava, Botrylloides diegensis , and Membranipora membranacea .
Styela clava increased slowly in abundance at study sites in Beverly, Massachusetts and Portsmouth, New Hampshire. We found no evidence of competitive dominance by S. clava , even though it is the competitive dominant in similar habitats elsewhere. Botrylloides diegensis rapidly became a dominant species after its arrival in the Great Bay Estuary, but this dominance was short-lived. B. diegensis persists in the estuary as an early colonist of primary space and as an epibiont on secondary substrates in established communities. Membranipora membranacea became the dominant epiphyte on laminarian kelps within two years. Although M. membranacea overgrew the native epiphytes Obelia geniculata and Electra pilosa in the overwhelming majority of encounters these native species are more common on other algal hosts. Therefore, competitive dominance is not likely a factor in the successful invasion of the Gulf of Maine by M. membranacea .
These species provide evidence for opposing views of the role of competition in mediating community invasion. We show that ecological similarity among species is not an accurate criterion to predict either the mechanism of invasion or the means of persistence. In addition, these data indicate that biological invasions must be examined on broad spatial and temporal scales; short-term or narrowly focused studies can lead to incorrect conclusions. 相似文献
Styela clava increased slowly in abundance at study sites in Beverly, Massachusetts and Portsmouth, New Hampshire. We found no evidence of competitive dominance by S. clava , even though it is the competitive dominant in similar habitats elsewhere. Botrylloides diegensis rapidly became a dominant species after its arrival in the Great Bay Estuary, but this dominance was short-lived. B. diegensis persists in the estuary as an early colonist of primary space and as an epibiont on secondary substrates in established communities. Membranipora membranacea became the dominant epiphyte on laminarian kelps within two years. Although M. membranacea overgrew the native epiphytes Obelia geniculata and Electra pilosa in the overwhelming majority of encounters these native species are more common on other algal hosts. Therefore, competitive dominance is not likely a factor in the successful invasion of the Gulf of Maine by M. membranacea .
These species provide evidence for opposing views of the role of competition in mediating community invasion. We show that ecological similarity among species is not an accurate criterion to predict either the mechanism of invasion or the means of persistence. In addition, these data indicate that biological invasions must be examined on broad spatial and temporal scales; short-term or narrowly focused studies can lead to incorrect conclusions. 相似文献
36.
David Goulson Jemma L. Cruise Kate R. Sparrow Adele J. Harris Kirsty J. Park Matthew C. Tinsley Andre S. Gilburn 《Behavioral ecology and sociobiology》2007,61(10):1523-1529
Flowers exhibit great intra-specific variation in the rewards they offer. At any one time, a significant proportion of flowers
often contain little or no reward. Hence, foraging profitably for floral rewards is problematic and any ability to discriminate
between flowers and avoid those that are less rewarding will confer great advantages. In this study, we examine discrimination
by foraging bees among flowers of nasturtium, Tropaeolum majus. Bee visitors included carpenter bees, Xylocopa violacea, which were primary nectar robbers; honeybees, Apis mellifera, which either acted as secondary nectar robbers or gathered pollen legitimately and bumblebees, Bombus hortorum, which were the only bees able to gather nectar legitimately. Many flowers were damaged by phytophagous insects. Nectar volume
was markedly lower in flowers with damaged petals (which were also likely to be older) and in flowers that had nectar-robbing
holes. We test whether bees exhibit selectivity with regards to the individual flowers, which they approach and enter, and
whether this selectivity enhances foraging efficiency. The flowers approached (within 2 cm) by A. mellifera and B. hortorum were non-random when compared to the floral population; both species selectively approached un-blemished flowers. They both
approached more yellow flowers than would be expected by chance, presumably a reflection of innate colour preferences, for
nectar standing crop did not vary according to flower colour. Bees were also more likely to accept (land on) un-blemished
flowers. A. mellifera gathering nectar exhibited selectivity with regards to the presence of robbing holes, being more likely to land on robbed
flowers (they are not able to feed on un-robbed flowers). That they frequently approached un-robbed flowers suggests that
they are not able to detect robbing holes at long-range, so that foraging efficiency may be limited by visual acuity. Nevertheless,
by using a combination of long-range and short-range selectivity, nectar-gathering A. mellifera and B. hortorum greatly increased the average reward from the flowers on which they landed (by 68% and 48%, respectively) compared to the
average standing crop in the flower population. Overall, our results demonstrate that bees use obvious floral cues (colour
and petal blemishes) at long-range, but can switch to using more subtle cues (robbing holes) at close range. They also make
many mistakes and some cues used do not correlate with floral rewards. 相似文献
37.
To investigate copepod nauplii ingestion rates on phytoplankton, we have adapted the traditional gut fluorescence technique
as it can be used with lower gut pigment concentrations. With the improved technique, laboratory experiments were performed
to estimate functional responses for nauplii of Calanus helgolandicus and Centropages typicus. Nauplii were raised from eggs to copepodites and the experiments were performed with stages NIV-NV. Gut evacuation rates
and ingestion rates were measured on Isochrysis galbana at different concentrations. Specific ingestion rates ranged between 0.038–0.244 μg C μg−1 nauplii C d−1 for C. typicus and 0.041–1.412 μg C μg−1 nauplii C d−1 for C. helgolandicus. Both species showed a type III functional response, reaching a saturation concentration at around 600 μgC l−1 for C. typicus and 800 μgC l−1 for C. helgolandicus.
An erratum to this article can be found at 相似文献
38.
Cripe GM McKenney CL Hoglund MD Harris PS 《Environmental pollution (Barking, Essex : 1987)》2003,125(2):295-299
Pest control agents, such as juvenile hormone analogues (JHA), have been developed to limit effects on non-target organisms that co-inhabit insect pest habitats. Rhithropanopeus harrisii, an estuarine xanthid crab, was used to observe the impacts of the JHA, fenoxycarb, on the pattern of complete larval development as well as survival of larvae and successful metamorphosis to first crab stage. Significant mortality occurred in the first of four zoeal stages (after 2-3 days of exposure) at the highest treatment of 240 microg fenoxycarb/l and in megalopae exposed to 48 microg fenoxycarb/l. The time required to metamorphose to the first crab stage was significantly increased for megalopae in all treatments 48 microg/l. This delay in development was sufficient to significantly prolong the entire developmental period from zoea to crabs. Unexposed larvae developed to crabs in an average of 16 days; larvae exposed to >/=48 microg/l required 19-20 days. Reduced survival and extended duration of developing larval stages in the life history of a benthic invertebrate may alter the population dynamics of these organisms in the estuary. 相似文献
39.
40.
J R Miles C R Harris D C Morrow 《Journal of environmental science and health. Part. B》1983,18(3):305-315
To study problems associated with pesticide container disposal, a small vegetable production area in southwestern Ontario, the Thedford Marsh, was selected as the site for a model study. A container collection system was organized during the 1981 growing season, with collections being made from the ca. 50 growers on the marsh twice each month. In addition to the regular collection program a cleanup service for empty pesticide containers stored on farms or discarded on public lands also was initiated. More than 3600 containers were collected and disposed of at an authorized landfill site. Ca. 2/3 were herbicide containers, ca. 1/4 were insecticide containers, and 3% were fungicide containers. Unrinsed containers contained as much as 5 1/2% of the original contents with an average of 1%. Containers rinsed by the triple rinse method or using rinsing devices (E-Z Rinse, JET Rinse) generally contained less than 0.1% of the original content. Some formulations presented rinsing problems due to settling and caking. The results indicated that, while unacceptable quantities of pesticide residues remain in unrinsed containers, most rinsed pesticide containers will be acceptable for disposal at municipal sanitary landfill sites. 相似文献