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71.
As part of a study into the ecology of the recently introduced macroalga Undaria pinnatifida in the British Isles, the competitive ability of this adventive kelp with native species was investigated in Torquay Marina (Devon, UK). Sites of introduction were surveyed for the presence of native species filling a similar ecological niche and long-term competition experiments set up over 6 years. Experiments involving clearance, removal and monitoring showed that Undaria has a low competitive ability in the infralittoral and sublittoral of a rocky breakwater. Undaria did not manage to colonise the nearby (200 m) shoreline for at least 7 years from the date of its original introduction to the floating pontoons of Torquay Marina. Undaria did out-compete native species in a marina environment: two kelp species, Laminaria digitata and Laminaria saccharina, and a sea squirt, Styela clava. 相似文献
72.
John W. Chapman James T. Carlton M. Renee Bellinger April M. H. Blakeslee 《Biological invasions》2007,9(6):737-750
The European periwinkle snail, Littorina littorea was discovered in Pictou, NS, Canada in 1840. This snail’s subsequent rapid, conspicuous spread south from Pictou along the
Canadian maritime coast and then along the New England and mid-Atlantic coast to New Jersey, its virtual absence in pre-European
contact deposits, and its close association with human mechanisms of transport from Europe are among the clearest evidence
for a human-mediated introduction. However, molecular genetic data have been proposed as evidence that L. littorea’s occurrence in North America was not the result of a human introduction by Wares et al. (Ecol Lett 5:577–584, 2002). Reexamination
of these genetic data and reexamination of all other data available reveal that a human-mediated introduction of L. littorea is the simplest explanation of its occurrence in North America. The refutation of the human-mediated introduction of L. littorea was premature. 相似文献
73.
Dominique G. Roche Mark E. Torchin Brian Leung Sandra A. Binning 《Biological invasions》2009,11(4):983-993
As the rate of biological invasions continues to increase, a growing number of aquatic introduced species are becoming globally
widespread. Despite this ubiquitous phenomenon, rarely do we discover aquatic invaders early enough to allow the possibility
of eradication. Recently, the North American Harris mud crab (Rhithropanopeus harrisii) was found in the waters adjacent to the Panama Canal and herein we provide an assessment of the crab’s distribution in Panama
to evaluate the possibility of eradication. Using salinity tolerance experiments, we also evaluate the potential for further
spread of this crab within the Canal. Our results suggest that populations of R. harrisii are currently limited to two manmade lagoons which are adjacent to the Panama Canal. Our experiments suggest that both juvenile
and adult R. harrisii can survive in salinities found outside its current range in Panama. Although it is difficult to predict the potential for
future spread and impacts in Panama, current management strategies could reduce the probability for spread locally as well
as elsewhere in the world given the intensity of shipping in this region. The current containment of this invader suggests
that a localized eradication may be possible. 相似文献
74.
The isolated archipelagos of Remote Oceania provide useful microcosms for understanding the impacts of initial human colonization.
Palaeoecological data from most islands reveal catastrophic transformations, with losses of many species through over-hunting,
deforestation and the introduction of novel mammalian predators, the most ubiquitous and devastating being commensal rats.
Two case studies from the Austral Islands and New Zealand demonstrate the potential of direct human proxies from palaeoecological
archives to detect initial human impacts on islands. We show how pollen from introduced crop plants, and buried seeds with
gnaw marks from the introduced Pacific rat (Rattus exulans) provide a reliable means of detecting initial human colonization and highlight the downstream ecological consequences of
agriculture and rat introduction on previously uninhabited pristine island ecosystems. Previous studies have relied on indirect
signals of human arrival based on charcoal and associated vegetation changes, the causes of which are often more difficult
to interpret with certainty. 相似文献
75.
Elsa Bonnaud Karen Bourgeois Eric Vidal Jérôme Legrand Matthieu Le Corre 《Population Ecology》2009,51(2):261-270
The Yelkouan shearwater, Puffinus yelkouan, is an endangered Mediterranean endemic species of burrowing petrel threatened by feral cats. The life-history parameters
of a small population of Yelkouan shearwaters on the Mediterranean island, Port-Cros, were studied in conjunction with the
diet of feral cats, to examine the birds’ vulnerability to introduced cats. Yelkouan shearwaters were the birds most frequently
found in cat scats, with 431 ± 72 birds killed per year, and predation highest during the pre-laying period. A demographic
model was created using data for P. yelkouan and for closely related shearwater species. Without cat predation, only two of four survival rate scenarios led to a mean
growth rate (λ) ≥ 1. The model was constrained to have a stable population growth rate and used to predict predation scenarios compatible
with the observed population stability, because the population under study has remained stable at around 180 pairs for at
least 20 years despite feral cat predation. The results of assuming that the population is closed were inconsistent with the
estimated mortalities due to feral cats, while it was possible to reconcile the observed numbers of breeding pairs with the
observed mortalities due to cats by assuming that Port-Cros Island is a sink sustained by immigration. This illustrates that
small colonies may need to be sustained by larger ones to avoid being driven to extinction. Unfortunately, the absence of
a large geographic-scale ringing program makes the precise identification of the origin of the immigrants impossible in this
case. 相似文献
76.
Oscar Skewes Fernando Gonzalez Rodrigo Olave Alberto Ávila Víctor Vargas Peter Paulsen Horst Erich König 《European Journal of Wildlife Research》2006,52(4):292-296
Castor canadensis specimens were imported from Canada and released in the wilderness on the Argentinean part of Tierra del Fuego (TDF) in the
year 1946. First studies on the development of the beaver population and subsequent environmental changes were conducted four
decades later and indicated a strong expansion of these animals, with negative effects on the forest, especially the dominant
Nothofagus sp. Between 1999 and 2001, we investigated the density of the beaver population in the Chilean part of TDF and the southern
adjacent island Navarino (NAV). Data were mapped into a geographical information system. The mean colony density was 1.03
(range: 0.15–1.91) and 1.1 per km watercourse for 75% of the area of TDF (mainly south and central region) and the total NAV
island, respectively. The average number of individuals estimated per colony was five. Based on these findings, the number
of beavers in the Chilean part of TDF and on NAV was estimated at 61,300 individuals. The population is increasing and expanding
in the Northern region, with a linear rate of 2.6–6.3 km/year. 相似文献
77.
We document the invasion of Chinook salmon (Oncorhynchus tshawytscha) to southern South America providing historical, current and future perspectives. We conducted field sampling, angler surveys,
and analyzed all written records, and found evidence of reproductive populations in more than ten Andean (and many more coastal)
watersheds draining mainly to the Pacific Ocean in Chile (39°–53° S), but also to the Atlantic Ocean in Argentina (50° S).
Invasion begun ∼25 years ago apparently from a few point sources of introduction by ocean ranching operations using spring-run
Chinook salmon originated from tributaries of the lower Columbia River, USA. The rapid spread suggests that Chinook salmon
were pre-adapted to their novel marine and freshwater environments because of similarities to equivalent North Pacific habitats,
and invasion may have been facilitated by low ecological resistance. Preliminary data suggest that populations express a latitudinal
gradient in juvenile migration life histories equivalent to that in their native range. Parallels to the only other establishment
of anadromous Chinook salmon outside their native range, New Zealand, suggests a predictable invasion rate. In South America,
the invasion is ongoing in southern areas, yet we deem unlikely colonization of rivers north of the range reached thus far.
This is the first anadromous salmon species to have invaded such a large range in South America, and it raises many evolutionary,
ecological, environmental and socioeconomic issues, with several discussed here.
相似文献
Cristián CorreaEmail: |
78.
Matt W. Hayward 《Biodiversity and Conservation》2009,18(4):765-775
Conservation managers are in the unenviable position of trying to conserve and restore biodiversity, without having a definitive
timeframe to restore it to. Currently, managers around the world focus on various timeframes from recent to historical, but
without a definitive target, countless conservation problems arise. Managers need to determine what constitutes a native species,
which species to reintroduce, whether selective breeding should be implemented to resurrect supposedly extinct organisms,
targets on population levels, whether assisted migration should be employed when climate change alters the environmental envelope
of a species surrounded by human-altered landscapes, and how to manage for stochasticity and evolutionary processes. Without
having definitive goals to target, these issues are difficult/impossible to address. It is only by discussing these important
issues that some consensus will be attained that allow us to stop responding to crises and start predicting the future of
biodiversity and plan and respond accordingly. 相似文献
79.
80.
Victor Carrion C. Josh Donlan Karl Campbell Christian Lavoie Felipe Cruz 《Biodiversity and Conservation》2007,16(2):437-445
Introduced herbivores are major drivers of ecosystem change and biodiversity loss, particularly on islands. Tools and techniques
now exist to routinely remove introduced herbivores from islands, providing a powerful conservation tool. Here, we summarize
the few documented feral donkey removals on islands worldwide, and report on the removal of populations from the Galápagos
archipelago, Ecuador. After decades of sporadic control programs on Santiago Island and Alcedo Volcano, Isabela Island, donkey
populations were removed from both areas, concurrent with a goat eradication program. Both ground and aerial hunting programs
were utilized. The latter method was highly efficient; donkeys were removed from Santiago Island with less than 80 h of aerial
hunting. Given the clear impacts of introduced herbivores on islands worldwide, feral donkey populations should be routinely
removed from islands. 相似文献