Neighborhood watch: rising threats to freshwater fishes

 By Stephanie Januchowski-Hartley, Guest Blogger

Illustrations by Hannah Dean

Imagine you live in a small neighborhood with limited places to access food or resources. What if, in addition to living in a small neighborhood, 30% of your neighborhood were also under an activity that impacts you in a negative way? Say it is under construction and you can’t get to the grocery store most days. How would this disturbance affect your condition or persistence in your neighborhood, probably in a negative way, right?


In a similar way, there are many species on the planet that live in relatively small neighborhoods, or range areas if you will, and these species are often more susceptible to extinction because they occur in a small area and changes to the area can have a relatively big impact on their survival. Conservation scientists, are often concerned with the conservation of species that live in small neighborhoods because of their sensitivity to global changes such as human land use. Changes in human land use can present both expanding threats and opportunities for the conservation of species. Knowing where species and human land uses occur, and how these could be changing through time, is important information needed to understand how species’ extinction risk could also be changing through time.


We recently looked into which freshwater fish species in the United States live in relatively small neighborhoods (in this case neighborhoods smaller than 20,000 km2), and assessed which of these species are currently experiencing high amounts of human land use in their neighborhood and how this could change by the year 2051.

You might be wondering how we were able to know what land use will be like in 2051. That’s a good question! In fact, we don’t know for sure what land use will be like in 2051, so we dusted off our crystal ball!  No, no, I promise no crystal balls were involved, instead we used projections based on historical economic data and land use information that allowed us to estimate what land use might look in the future depending on economic decisions and policies in the US.

So, what did we find? It turns out that roughly half, 407 of the 799 known freshwater fishes in the United States live in small neighborhoods. Of the fishes living in small neighborhoods, 57 of them are most likely to be strongly affected by intensive land use based on the amount of human land use in their neighborhood both now and in the future. This is relevant to the conservation of these species because only 15 of them are currently listed as threatened on the IUCN Red List, and only six are listed as threatened under the Endangered Species Act. Species listed as threatened on the IUCN Red List and Endangered Species Act are important because these listings influence how much money, time and effort are allocated to the conservation of these species.


Our research suggests that greater attention should be paid to these 57 species that live in small neighborhoods and who are likely to lose substantial areas of their habitat in the next 50 years.

Keep an eye and ear out for these fishes and remember their neighborhoods matter too.

The study referenced in this blog post was written by Stephanie Januchowski-Hartley et al. and published 4 March 2016 in Diversity and Distributions. You can also download the list of 57 species referenced in this article, here.

2 Comments Add yours

  1. jakerns says:

    What are the 57 species?

  2. Cory Hoffman says:

    I really enjoy reading this blog, but why do you almost never cite your sources? I’d like to read the research you’re talking about here.

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