Gravel-bed rivers and their floodplains are the lifeblood of ecosystems and need to be allowed to run and flood unimpeded if species are to be protected and communities are to cope with climate change, a ground-breaking scientific study has found.
The broad valleys formed by rivers flowing from glaciated mountains, such as those found throughout B.C. and Alberta, are some of the most ecologically important habitats in North America, according to the team of scientists who have done the first extensive study of the full range of species that rely on gravel-bed rivers, ranging from microbes to bears. The paper was published online Friday in Science Advances.
In the region that stretches from Yellowstone National Park in Wyoming to the northern Yukon, gravel-bed river flood plains support more than half the plant life. About 70 per cent of the area’s bird species use the floodplain, while deer, elk, caribou, wolves and grizzly bears use the plains for food, habitat and as important migration corridors.
While everyone knows that fish rely on rivers, the scientists found that species such as cottonwood trees need the river flood to reproduce and the ever-changing landscape of changing channels and shifting gravel and rocks supports a complex food web.
Gravel-bed rivers are much more than water flowing through the channel, said lead author Ric Hauer, director of the University of Montana’s Center for Integrated research on the Environment.
“The river flows over and through the entire floodplain system, from valley wall to valley wall, and supports an extraordinary diversity of life. The river is so much bigger than it appears to be at first glance,” he said.
But the floodplains are endangered worldwide as the flat, productive valleys are attractive for agriculture, roads or houses and it is time to look at gravel bed rivers with new eyes, said Harvey Locke, co-founder of the Yellowstone to Yukon Conservation Initiative and one of the study’s authors.
“A wild and free river drives the life support system across the whole landscape and we need to keep them happy,” Locke said in an interview with DeSmog Canada.
“We need to let them be rivers and run free and do our development respecting that need instead of trying to control them.”
That means not building dams or levees that prevent essential flooding, Locke said.
“Flooding is critical to the health of the riparian system and, by extension, organisms across the whole landscape and, when you put in a dam for climate change mitigation you are killing that process. It’s a catastrophe not only for the immediate ecological effects, but it also puts a huge barrier to connectivity so species cannot go up the river to adapt to climate change,” Locke said.
Hydro dams are often touted as green energy, but, in reality they are a huge problem, not a solution to climate change, he said.
Locke emphasized that the scientific study does not look at the controversy behind individual projects such as the planned Site C dam in northeastern B.C., but said he personally regards Site C as a prime example of the problem.
Existing dams on the Peace River have already had a devastating effect downstream, he said.
“And the horror of wrecking more of that beautiful river valley around Fort St. John is an example of not thinking clearly. It’s very bad for the resilience of the landscape,” he said.
Gravel-bed rivers are found mainly in the western U.S. and Canada — and include major rivers such as the Columbia, Fraser, Flathead, Mackenzie and Yukon — and every part of B.C is affected by them, said Locke, who is hoping the scientific paper will attract the attention of groups such as planners and politicians who make development decisions.
“The really big point is that gravel-bed river systems are the heart of the whole landscape and you don’t want to clog the arteries attached to the heart, which is what a dam does,” he said.
Even in protected areas such as Yellowstone and Banff national parks, humans have altered the floodplains, the scientists found.
Hauer said the increasing pressures of climate change mean that species need access to intact gravel-bed ecosystems in order to survive.
“These systems must be protected and those that are already degraded must be restored,” he said.
Biologist and grizzly bear expert Michael Proctor, of Birchdale Ecological, one of the report’s authors, said the research highlighted how river systems are a focus of regional connectivity, not only for grizzly bears, but for all species.
“This paper helped me realize the amazing significance of gravel bed river systems, not just river valleys, as an ecological focus and arena of so much biodiversity and ecological processes,” Proctor said.
“It’s like the narrow pinch point in an hour-glass of influence. Everything is influenced by that pinch point.”
Human settlement and activities in those river valleys and floodplains reduces their biodiversity and significance, Proctor said.
“We need to leave and even restore some portions of these river systems to more of a natural condition,” he said.
Photo: Flathead River by Harvey Locke
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Mito ya mchanga na mabonde yao ya mafuriko ni damu ya uhai ya mifumo ya ikolojia na inahitaji kuruhusiwa kukimbia na mafuriko bila vizuizi ikiwa spishi zinapaswa kulindwa na jamii zinapaswa kukabiliana na mabadiliko ya hali ya hewa, utafiti wa kisayansi wa msingi umegundua. Bonde pana lililofanyizwa na mito inayotiririka kutoka milimani yenye barafu, kama zile zinazopatikana kotekote B.C. Alberta ni moja ya maeneo muhimu zaidi ya mazingira katika Amerika ya Kaskazini, kulingana na timu ya wanasayansi ambao wamefanya utafiti wa kwanza wa kina wa aina zote za wanyama wanaotegemea mito ya mchanga, kuanzia vimelea hadi dubu. Karatasi hiyo ilichapishwa mtandaoni Ijumaa katika Maendeleo ya Sayansi. Katika eneo la Yellowstone, Wyoming, na kaskazini mwa Yukon, kuna maeneo ya chini ya ardhi yenye mchanga. Karibu asilimia 70 ya spishi za ndege katika eneo hilo hutumia eneo hilo, huku nyati, elk, caribou, mbwa mwitu na dubu wa rangi ya kijivu wakitumia eneo hilo kama chakula, makazi na njia muhimu za uhamiaji. Ingawa kila mtu anajua kwamba samaki hutegemea mito, wanasayansi waligundua kwamba spishi kama vile miti ya cottonwood zinahitaji mafuriko ya mto ili kuzaliana na mandhari inayobadilika daima ya kubadilisha mifereji na kuhamisha mchanga na miamba inasaidia mtandao tata wa chakula. "Mito ya mchanga ni zaidi ya maji yanayotiririka kupitia mfereji, ""alisema mwandishi mkuu Ric Hauer, mkurugenzi wa Chuo Kikuu cha Montana cha Kituo cha Utafiti wa Pamoja juu ya Mazingira." <unk>Mto huo unapita juu na kupitia mfumo wote wa bonde la mafuriko, kutoka ukuta wa bonde hadi ukuta wa bonde, na hutegemeza utofauti wa ajabu wa maisha. Mto ni mkubwa sana kuliko unavyoonekana kwa mtazamo wa kwanza, "alisema. "Lakini mabonde ya mafuriko yanakabiliwa na hatari ulimwenguni kote kwani mabonde ya tambarare, yenye uzalishaji yanavutia kwa kilimo, barabara au nyumba na ni wakati wa kuangalia mito ya mchanga kwa macho mapya, ""alisema Harvey Locke, mwanzilishi mwenza wa Yellowstone kwa Yukon Conservation Initiative na mmoja wa waandishi wa utafiti." "Mto wa mwitu na huru huendesha mfumo wa kuunga mkono maisha katika mandhari nzima na tunahitaji kuwafanya wawe na furaha", Locke alisema katika mahojiano na DeSmog Canada. "Tunahitaji kuwaacha kuwa mito na kutembea kwa uhuru na kufanya maendeleo yetu kuheshimu mahitaji hayo badala ya kujaribu kuwadhibiti. "" Hiyo inamaanisha kutojenga mabwawa au mabwawa ambayo huzuia mafuriko muhimu, Locke alisema." Mafuriko ni muhimu kwa afya ya mfumo wa pwani na, kwa upanuzi, viumbe katika mazingira yote na, wakati wewe kuweka katika bwawa kwa ajili ya kupunguza mabadiliko ya hali ya hewa wewe ni kuua mchakato huo. "Ni msiba, si tu kwa madhara ya moja kwa moja ya ikolojia, lakini pia huweka kizuizi kikubwa kwa muunganisho ili spishi zisiweze kwenda juu ya mto ili kukabiliana na mabadiliko ya hali ya hewa, ""Locke alisema." "Damu za maji mara nyingi huitwa ""nishati ya kijani,"" lakini kwa kweli ni tatizo kubwa, sio suluhisho la mabadiliko ya hali ya hewa." Locke alisisitiza kuwa utafiti wa kisayansi hautazama utata nyuma ya miradi ya mtu binafsi kama vile bwawa la Site C lililopangwa kaskazini mashariki mwa B.C., lakini alisema yeye binafsi anajiona Site C kama mfano bora wa tatizo hilo. Mabwawa yaliyopo kwenye Mto Amani tayari yamekuwa na athari mbaya chini ya mto, alisema. "Na hofu ya kuharibu zaidi ya bonde hilo zuri la mto karibu na Fort St. John ni mfano wa kutofikiria waziwazi. """ Ni mbaya sana kwa ajili ya uimara wa mazingira, "alisema. Mito ya mchanga hupatikana hasa magharibi mwa Marekani na Canada na inajumuisha mito mikubwa kama vile Columbia, Fraser, Flathead, Mackenzie na Yukon na kila sehemu ya BC inaathiriwa na wao, alisema Locke, ambaye anatumaini karatasi ya kisayansi itavutia umakini wa makundi kama vile wapangaji na wanasiasa ambao hufanya maamuzi ya maendeleo. "Kitu kikubwa ni kwamba mifumo ya mito ya mchanga ni moyo wa mandhari nzima na hutaki kuziba mishipa iliyounganishwa na moyo, ambayo ni nini bwawa hufanya", alisema. Hata katika maeneo yaliyohifadhiwa kama vile mbuga za kitaifa za Yellowstone na Banff, wanadamu wamebadili maeneo ya mafuriko, wanasayansi hao walipata. Hauer alisema shinikizo linaloongezeka la mabadiliko ya hali ya hewa linamaanisha kwamba spishi zinahitaji ufikiaji wa mifumo ya ikolojia ya mchanga ili kuishi. "Mifumo hii lazima ilindwe na ile ambayo tayari imeharibiwa lazima irudishwe", alisema. Michael Proctor, mtaalamu wa maziwa ya dubu wa kijivu kutoka Birchdale Ecological, alisema utafiti huo unaonyesha jinsi mifumo ya mito inavyohusisha uhusiano wa kikanda, sio tu kwa dubu wa kijivu, lakini kwa spishi zote. "Karatasi hii ilinisaidia kutambua umuhimu wa kushangaza wa mifumo ya mito ya mchanga, sio tu mabonde ya mto, kama mwelekeo wa ikolojia na uwanja wa utofauti wa kibiolojia na michakato ya ikolojia", Proctor alisema. <unk>Ni kama hatua nyembamba pinch katika saa-glasi ya ushawishi. Kila kitu huathiriwa na hatua hiyo ya pinch. <unk> Makazi ya binadamu na shughuli katika mabonde hayo ya mto na mabonde ya mafuriko hupunguza utofauti wao wa kibiolojia na umuhimu, Proctor alisema. "Tunahitaji kuondoka na hata kurejesha sehemu fulani za mifumo hii ya mito kwa hali ya asili zaidi", alisema. "Mto Flathead, Harvey Locke, ""Mto wa Taku"" ni mto wa mto wa Taku, ambao ni mto wa mto wa Taku, ambao ni mto wa mto wa Taku." "Hii ni mahali patakatifu,"" alisema Waziri wa Fedha wa Alberta, ambaye alitangaza bajeti ya mwaka huu, akisema ""Bado tunaendelea kutegemea mapato kutoka kwa sekta ya mafuta na gesi.""" Hivi karibuni alipimwa kuwa na ugonjwa wa neva usioweza kutibiwa, na kusababisha wasiwasi kwa...