Archive for the ‘Global warming’ Category

A recent study published in the journal Proceedings of the Royal Society B found that in the case of marine animals, geographic range is the key determinant of a species’ extinction risk.

The study was led by Paul Harnik of the National Evolutionary Synthesis Center, and along with Carl Simpson from the Museum für Naturkunde and Jonathan Payne of Stanford University. Together, they studied over 6500 marine animal fossils from 500 million years ago, looking for common factors in extinction rates. They found a pattern among the fossils indicating that marine species with narrow ranges are more likely to go extinct than other species.

The study challenges common assumptions that rare species are most likely to face extinction. The term ‘rare’, the study found, could be applied to a number of factors, including population size, geographic range, or the animal’s tolerable habitat range (that is, where they are capable of surviving outside of their established range). In fact, animals with both a narrow geographic range and a small range of habitat were six times more likely to go extinct than animals with healthy populations and adequate ranges.

The significance of this study lies in its relevance to the impact of climate change and human development on oceans and ocean animals. The article cites global warming, ocean acidification, and overfishing as three main factors affecting marine animals’ ranges. Global warming, in particular, directly affects ocean ranges by causing marine areas to warm up, decrease in size, or change in other measurable ways. As these changes occur, a species’ range becomes more narrow, increasing the species’ risk of extinction.

Thus, climate change has a more significant affect on marine wildlife than what was perhaps initially understood. While ocean acidification and overfishing directly impact a species’ population numbers, it is the range of that species that determines its chance of survival. Therefore, the erect-crested penguin, found in healthy numbers but along only a small section of New Zealand coast, could be as at-risk as polar bears, whose numbers are small but whose range is significantly larger than that of the  penguin’s. Combating climate change and its affects on wild species is a two-part battle: we must protect the species that are declining in population as well as those species who seem to be thriving, but have small, restrictive geographic ranges.


EurekaAlert Article


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Proximate vs. Ultimate Cause


This article, written by George Wuerthner for The Wildlife News, examines the differences between proximate and ultimate causes of behavioral and environmental changes. A proximate cause is immediate: A bull elk fights off another bull because he wants to eliminate mating competition in an area. The ultimate cause, however, is the elk’s biological drive to succeed at procreation.

Wuerthner’s article focuses specifically on the effects of the livestock industry on sage grouse populations. In this instance, climate change is the proximate cause of drought, wildfires, and increased cheatgrass growth, which reduces cover and makes the grouse an easier prey for hawks. However, the ultimate cause of increased predation is the livestock industry, and specifically, the methane produced by cattle rumen. Methane is one of the major contributors to global warming, and it is this warming that causes the drought, which increases fires, which destroys local cover, which promotes the invasion of cheatgrass.

This section of Wuerthner’s article made me think about my recent post discussing the effects of climate change on wildlife. It’s easy for society to fixate on the shrinking polar ice caps, rising sea levels, and expanding deserts when considering the effects of climate change. Society rarely looks at the seemingly less significant repercussions these changes are having on the environment. Increased grouse predation and declining grouse populations might seem trivial in comparison to melting ice caps, but as we well know, everything within an environment is inherently related. Low grouse numbers may cause hawks to seek out new hunting grounds, thus leading to increased populations in their other prey in the grouse’s habitat. Or perhaps  hunters who sought out the grouse will find an alternative animal to hunt, one that has a lower population threshold. We can’t definitively predict what the consequences grouse decline might be, but we do know that any time a species is reduced or eliminated from a habitat, that habitat is absolutely altered.

I appreciated this article’s focused examination of the impact of climate change on a single species, and like how the author tied climate change and causation together in his discussion.  Looking at the proximate and ultimate effects of climate change is a useful way to understand the scope of its influence on the environment. It’s important to understand that impact on a smaller, local scale, instead of only considering the more obvious, global repercussions.

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Escaping the Heat: Wildlife Responds to Climate Change


Rising temperatures are affecting wildlife and their environments in several measurable ways, including their range boundaries. As climates heat up, animals are leaving their long-established habitats in search of cooler temperatures. Mountain-dwellers such as pika and chipmunks are moving upwards to higher elevations, while the Southern flying squirrels, American goldfinch, and the brown argus butterfly are all heading further north. These animals are just a few of hundreds that are redefining their habitat range as global temperatures increase. As these relocations take place, new communities are created in which species coexist in environments they did not used to share. This challenges both the resources in the affected environments as well as the predator-prey dynamics in these areas, and those that animals have left behind.

While a global rise in temperatures is indisputable, the cause of this temperature increase has been the source of debate for years. But “. . . it makes no difference to plants and animals what’s causing the warming,” states Theresa Root, a biologist at Stanford University. Indeed, it is the aftermath of rising temperatures that we must acknowledge first. A nature reserve no longer serves a purpose if the species it was designed to protect have moved beyond the reserve’s boundaries in search of cooler temperatures. Instead, the reserve may become irrelevant, a swath of land unusable by both humans and wildlife. And as affected species search for new habitats, they will eventually run out of protected land and encounter suburbs, impassable highways, or the top of a mountain–at a certain point, they will run out of options.

Thus, the role of the environmental agent has shifted. While conservation efforts once focused on the separation of humans and wildlife, we may need to begin interfering in order to regulate populations and accommodate shifting habitats, from manually relocating species who are struggling in their current, overheated habitats, to replenishing food supplies in a specific environment. On the other hand, if we do not step in and assist animals’ attempts to find cooler habitats, we must be prepared to accept a different environmental map in the coming years, as certain species become extinct and others find new areas to inhabit. Anthony Barnosky, a paleoecologist at the University of California, Berkley, asks, “You have to decide, am I interested in a species? Am I interested in a landscape? Or am I interested in a feeling of wildness?”


This article is a compelling example of the constant struggle between humans and nature. Despite our best attempts to protect wildlife and the environment through nature reserves, protected lands, and national forests, the species in these areas are still struggling to defend themselves against natural changes that are beyond immediate control. And just as we need to redefine what it means to protect wildlife, we also need to re-examine what it means to conserve wildlife and the environment in light of climate change and shrinking habitats. We need to focus on the “how” instead of the “why”. That is, instead of fixating on why temperatures are on the rise, and whether it is caused entirely or in part by humans, we need to look at how we can work around rising temperatures to ensure the safety of wildlife and the environment in spite of warming climates. Using predictive models to understand where species will relocate as temperatures rise, establishing new nature reserves to accommodate species as they move north, and encouraging that relocation with wildlife bridges and corridors are just a few ways we can help wildlife find new environments despite warming climates and expanding suburbs.

But we cannot completely disregard the “why”. After all, if humans are not the main cause of global warming, is it in the environment’s best interest for us to interfere with a natural process? Animals and habitats have been changing, relocating, dying out, and re-establishing themselves for millions of years because of natural influences such as rising temperatures. Would it be ethical to intervene in a natural process, no matter how drastic the changes might be? If, however, we conclude that global warming is caused by human influence, does it become our duty to rearrange nature? How much intervention, whether good or bad, is beneficial? At a certain point, is nature better off left to fix what we have broken on its own?

I’m eager to follow this trend carefully over the coming years. I would like to see more current studies discussing humans’ influence on climate change and compare them to this article (the majority of the reports cited in this article were from 2009). What has changed in the last three years? What can we expect to change in the next three years, and in the years after that? When will our impact on global warming reach a point when we can’t ignore it anymore, and force us to take ownership? Will we find a way to reduce the effects of climate change on wildlife before it’s too late, before the pika, in its search for cooler temperatures, reaches the top of the mountain?

See link for original article, quotes, and references.

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