Blue Planet Project Alien Species Pdf Download --
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The "alien" in question is ice plant (Carpobrotus edulis), a fast-growing succulent familiar to anyone who's spent time on the California coast, where it sprawls across seaside dunes and bluffs in dense green mats. It may look harmless, but its innocent appearance hides a sinister impact on local ecosystems. That's why students from Gault Elementary School in Santa Cruz, California, supported by a NOAA Ocean Guardian School grant, have taken it upon themselves to protect their shores from this unwelcome intruder.
Originally from South Africa, ice plant was introduced to California in the early 1900s to help stabilize soil along railroad tracks. The newcomer fared extremely well in California's sunny, cool climate, and rapidly spread up and down the coast.
In Santa Cruz, the Gault School's hands-on, community-based restoration project has enlisted students and volunteers to remove ice plant along the shores of Monterey Bay National Marine Sanctuary and restore the native coastal ecosystem to its natural beauty. In addition to removing the invasive plants, students are growing ten native species from seed and planting over 3,000 of these native plants in the restored sites. These newly planted coastal sites are already showing signs of positive changes with the increased presence of migratory birds and native pollinators like bees, butterflies.
As the students and their teachers participate in these restoration activities, they are also learning scientific research and restoration monitoring skills from real scientists so they can accurately evaluate changes in the number and diversity of plants and animals as well as long-term effects on coastal erosion. One of the tools students will use allows them to create a 3-D image of the coastline to monitor changes over time.
The students' Ocean Guardian School restoration project is being cheered on by the local community and visitors, and supported by a number of community partners including the City of Santa Cruz, Seabright Neighborhood Association, California State Parks, US Geological Survey, California Native Plant Society, Oikonos Ecosystem Knowledge, Patagonia, UC Santa Cruz, and the California Coastal Conservancy. In time, with the students' focused efforts, the days of the invading ice plant may be numbered!
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The rate at which humans translocate species beyond their native ranges has substantially increased during the last centuries1,2,3. The unprecedented intensity of human-mediated species exchange leads to the homogenization of floras and faunas4, re-defines the classical boundaries of biogeography5 and has far-reaching implications for native biota, ecosystem functioning, human health and economy6,7,8. However, although the general rise in the number of alien species is undisputed, we know little about the temporal dynamics of alien species accumulation and how this might vary among taxonomic groups and geographic regions.
To address these gaps in our knowledge, we compiled a global data set of regional first records of alien species that are now established (following the criteria in ref. 12) in multiple geographic regions worldwide (countries and sub-national regions such as islands). This data set of 45,813 first records of 16,926 established alien species from a wide range of taxonomic groups is invaluable for assessing taxonomic and geographic variation in alien species accumulations, and for testing for evidence of slowdown in the accumulation rates. It covers 282 non-overlapping regions from all continents, with particularly intense sampling in Europe, North America and Oceania, and from well-studied taxa such as vascular plants, mammals, insects, birds and fishes (Fig. 1 and Supplementary Fig. 1). This data set allows us to analyse variations in the rate of alien species introductions across space and time in a consistent way over large geographic scales. In particular, we test the following predictions: (1) rates of introductions for species often intentionally introduced such as mammals, birds and vascular plants should decline in recent years as a result of increased awareness of their impacts and tighter biosecurity regulations; (2) rates of introductions for taxonomic groups primarily introduced accidentally such as invertebrates or algae should show steep increases in recent times, as these species are more difficult to regulate and are closely associated with increasing trade; and (3) significant geographic differences in the rates of alien species introductions should be apparent, reflecting variations in socio-economic histories and the strength of biosecurity regulations. We find that the number of established alien species and for most taxonomic groups even the rate of introduction increased until recently with no sign of saturation. We can therefore expect many more invasions to happen in the near future.
The global rate of first records (measured as the number of first records of established alien species per time unit) remained low between 1500 and 1800 (on average 7.7 first records annually, Fig. 2a). Since 1800, first records have increased constantly, only slowing during the two World Wars, to a maximum of 585 in 1996 (reflecting on average more than 1.5 new records per day). Our data set does not cover all alien species recorded in every region of the world and thus inevitably underestimates first record rates. The continuous rise in first record rates during the last 200 years is consistent across taxa (Fig. 2), except for mammals and fishes, whose rates have declined in recent decades (Fig. 2e,i). Remarkably, barring mammals and fish, there is no clear indication of a slowdown in the first records rates of alien species: rather, they are still increasing. This trend was consistent for both mainlands and islands (Supplementary Fig. 2).
Temporal trends in continental first record rates (that is, first records of established alien species on a continent per 5 years, dots) for various taxonomic groups and continents (for delineation of continents see Supplementary Fig. 12). It is noteworthy that for the inter-continental comparison, we only considered first records of established alien species on a continent, to avoid a bias due to varying numbers of countries in a continent, which resulted in a reduced number of first records (56% of the full data set). The trends are indicated by a running median with 25-year moving window (red line). Data after 2000 (grey dots) are incomplete and were removed from analysis. Time series with
Third, first record rates of vascular plants increased steeply in the nineteenth century and remained at high levels until the present (Fig. 2b), which was best represented by a sigmoidal increase of first record rates with time (Supplementary Fig. 3a). This trend can again be at least partly attributed to the colonization of North America and Oceania by European settlers and corresponding activities of institutions such as Acclimatization Societies in the nineteenth century. In addition, the foundation of many botanic gardens worldwide, a major pathway for plant introductions17, together with the increased international transport of living plants and propagules, and inventions such as the Wardian Case in 1829 (a mobile greenhouse to transport live plants), have promoted the establishment of alien plant species. In contrast to mammals and fishes, and contrary to our expectations, the first record rates of vascular plants remained high in the twentieth century, which is likely to be a consequence of the intensification of global trade18 and increasingly widespread cultivation of plants in agriculture, botanic and private gardens17.
Temporal patterns in the rates of first records on a continent (thereby excluding subsequent within-continental spread) vary distinctly across continents and taxonomic groups (Fig. 4 and Supplementary Fig. 6). Within taxonomic groups, there may be different pathways driving invasions of species that differ in their ecology and temporal patterns in these pathways are likely to vary among world regions. Indeed, we did not find a consistent pattern in the temporal trends within a taxonomic group across continents (Supplementary Fig. 7). Some of the observed inter-continental variation seems to be a consequence of European colonization, such as the steep increase of first record rates of alien vascular plants in the nineteenth century in North America and Oceania (Fig. 4). However, most of the inter-continental variation is difficult to explain, due to the lack of knowledge and data of the underlying processes, and the high inter-annual variation of the first record rates. Remarkably, most of these temporal variations in first record rates are nearly impossible to detect using cumulative numbers of alien species (Supplementary Fig. 8), a common way of presenting alien species accumulations.
The first record of an alien species may be the result of a human-mediated introduction of that species into a region, or a consequence of previous introductions into neighbouring areas and subsequent natural spread into adjacent regions. To remove the influence of introductions due to the species natural range expansion in the alien range, we considered only the first records of alien species on a continent, which revealed qualitatively similar, although less clear, trends compared with the full data set (Supplementary Fig. 9). First records are often influenced by a time lag between the actual introduction of a species and its detection19. The delay is likely to have decreased with time due to more intense sampling (for example, national species inventories) in recent decades, resulting in earlier detections of alien species after their introduction into new regions. However, the chronology of first record rates within the same taxonomic group should not change qualitatively (see Supplementary Notes for a detailed assessment of data quality and a discussion of the potential influence of varying sampling intensity on study results).
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