Navigation Links
Conservation of freshwater fish biodiversity: a challenge for the countries of the South
Date:3/26/2008

Humans have regularly been introducing exotic species into natural environments in order to provide for their nutritional necessities or meet less indispensable purposes such as horticulture, fishing or hunting. However, the particular environments are not always adapted for hosting new arrivals. Past introduction attempts, such as that of wild rabbit into Australia or brown fario trout into Southern hemisphere water courses, led to an awareness that these different species, qualified by scientists as none-native, have the power to upset an ecosystem. The 2002 Convention on Biodiversity recognized that the species introductions can cause regression of biological diversity, following destruction of natural habitats. Although it has long seemed likely that human activity plays a major role in such effects, no scientific study had yet yielded measurements of its involvement at planetary scale for a given group of species. An international research team comprising IRD, CNRS and University of Toulouse scientists recently published a study that gave the first real demonstration that human activity is the main driving factor behind the establishment of exotic fish species populations in river ecosystems. Examination of data on presence of around 10 000 freshwater fish in 1055 river basins covering both 80% immersed lands and 80% of globally recorded freshwater fish species allowed identification of seven species-invasion hot-spots: the Pacific coast of North America and Central America, Patagonia, southern and western Europe, South Africa and Madagascar, central Asia, the South of Australia and New Zealand (See Map). These regions are characterized by river basins where non-native species make up more than one quarter of the freshwater fish species recorded. Moreover, they are superimposed on biodiversity hot-spots which correspond to geographical zones a strong endemism rate and a very high total number of species.

The team also sought to determine the extent of the relative influence of the particular characteristics of each ecosystem and human activities on the diversity of the non-native fish species. Three hypotheses were tested: the biotic resistance, biotic acceptance and human activity. The first suggests that a high diversity of freshwater fish in the host ecosystem acts as a barrier to the establishment of non-native fish specie populations. The second postulates conversely that, for a given ecosystem, non-native species diversity follows that of native species because favourable ecological conditions for the latter are also suitable for the newly arrived species. As for the third, it takes account of the different indicators at river-basin scale (gross domestic product, percentage of land urbanized, population density), that can yield determination of the relation between anthropic pressure and non-native species diversity.

The three hypotheses relative weight was measured using statistical methods. For the whole set of river basins investigated, the environmental conditions of fluvial ecosystems were found to have practically no influence on the exotic species diversity. On the contrary, it is the human factors, and especially the intensity of economic activities measured by the GDP, which determine the number of non-native species present in a river basin. These results thus suggest that the economic development foreseen in the developing countries should be accompanied by a rise in the number of non-native freshwater fish species. Given that biological invasions are considered as one of the main causes of biodiversity loss, such a scenario would probably be detrimental to the aquatic biodiversity conservation of these regions. This study indicates that exceptional river ecosystems, like the Amazon Basin in South America or that of the Congo in central Africa, are still hardly affected by species introduction. For example, no more than 1% of the 3000 species of fish recorded in the River Amazon are non-native species. Just as a considerable number of countries of the South are seeing their economic growth take off, this kind of study should be useful in the future for setting up an effective watch system for the surveillance of the exotic species colonizing the most biodiversity-rich natural environments and make it possible to apply the principle of precaution before they become invasive.


'/>"/>

Contact: Gregory Flechet
fichesactu@paris.ird.fr
33-014-803-7607
Institut de Recherche Pour le Dveloppement
Source:Eurekalert

Related biology news :

1. Rwanda conservation effort to link isolated chimps to distant forest
2. Nations and conservation groups seek plan to protect Ghost of the Himalayas
3. Open-access tropical conservation journal launches
4. Scripps expedition provides new baseline for coral reef conservation
5. 2008 Pew Fellowship in Marine Conservation awarded to Dr. Marie-Joëlle Rochet from IFREMER
6. 2008 Pew Fellowship in Marine Conservation awarded to Fan Meng; first Chinese fellow
7. 2008 Pew Fellowship in Marine Conservation awarded to Dr. Ussif Rashid Sumaila
8. Dr. Andrew Constable awarded 2008 Pew Fellowship in marine conservation
9. 2008 Pew Fellowship in marine conservation awarded to UM Rosenstiels Dr. Andrew Baker
10. Pew Institute for Ocean Science awards 5 fellowships in support of global marine conservation
11. Conservation strategies must shift with global environmental change, says CU-Boulder study
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/7/2017)... 7, 2017   MedNet Solutions , an innovative ... of clinical research, is pleased to announce that the ... innovative, highly flexible and award winning eClinical solution, is ... iMedNet is a proven Software-as-a-Service (SaaS) clinical research ... (EDC), but also delivers an entire suite of eClinical ...
(Date:2/6/2017)... Feb. 6, 2017 According to Acuity ... driving border authorities to continue to embrace biometric ... are 2143 Automated Border Control (ABC) eGates and ... at more than 163 ports of entry across ... 2016 achieving a combined CAGR of 37%. APC ...
(Date:2/2/2017)... 2, 2017   TapImmune, Inc. (NASDAQ: ... specializing in the development of innovative peptide and ... cancer and metastatic disease, announced today it has ... of a second clinical lot of TPIV 200, ... alpha. The manufactured vaccine product will be used ...
Breaking Biology News(10 mins):
(Date:2/24/2017)... 2017 Provectus Biopharmaceuticals, Inc. (OTCQB: PVCT, ... clinical-stage oncology and dermatology biopharmaceutical company, today is ... in its previously announced rights offering of up ... common stock and Series C Convertible Preferred Stock ... As previously announced, the rights ...
(Date:2/24/2017)... Feb. 24, 2017 China Cord Blood Corporation (NYSE: ... leading provider of cord blood collection, laboratory testing, hematopoietic ... announced its unaudited financial results for the third quarter ... December 31, 2016. Third Quarter of Fiscal ... quarter of fiscal 2017 increased by 18.6% to RMB200.9 ...
(Date:2/24/2017)... , Feb. 24, 2017  OncoSec Medical Incorporated ... immunotherapies, will host a Key Opinion Leader event to ... an oral and poster presentation at the upcoming 2017 ... The KOL event will be held in-person and via ... EST / 9:00 AM PST at the Lotte New ...
(Date:2/23/2017)... 2017 /PRNewswire/ - The Fight Against Cancer Innovation Trust ... are pleased to report that Fusion Pharmaceuticals Inc. (Fusion) ... & Johnson Innovation – JJDC, Inc. (JJDC) as the ... TPG Biotechnology Partners, and Genesys Capital, as well as ... ...
Breaking Biology Technology: