The nested subset hypothesis was formulated to describe and explain patterns in the community structure of insular mammal faunas which are in the state of ‘relaxation’. The hypothesis states that the species comprising a depauperate fauna should constitute a proper subset of those in richer faunas, and that an archipelago of such faunas arranged by species richness should present a nested series. The non‐randomness of this pattern is evaluated for montane mammals in the American Southwest using Monte Carlo simulations under two sets of conditions. First, we constructed model archipelagos with the observed distribution of species richnesses, drawing individual species at random (without replacement) from the species pool (RANDOM0). Secondly, we constructed model archipelagos having the observed distribution of species richnesses, but weighted the selection of species by their actual frequencies of occurrence (RANDOM1). The degree of nestedness in the model archipelagos was then used to assess the non‐randomness of the observed structure. Actual Southwestern mammal faunas have a far more nested structure than model archipelagos produced by either RANDOM0 or RANDOM1, and there is virtually zero probability that observed structure is represented in the distribution of scores from either simulation run. Similar analyses were conducted on other archipelagos to determine the generality of this relationship and to identify variables putatively responsible for its production. Mammal faunas of large islands off the coast of Maine, U.S.A., studied by Crowell (1986) also comprise nested subsets, as do those inhabiting islands off the coast of Baja California, Mexico, studied by Lawlor (1983). Significantly, when the Baja archipelago is divided into landbridge islands (which are presumed to be relaxing to lower species level) and oceanic islands (where species number is limited by successful overwater dispersal), only the former show significant nestedness under the more stringent conditions of RANDOM1. These results and theoretical considerations suggest that selective extinction of species may be chiefly responsible for the nestedness in natural archipelagos. Our conclusions have obvious implications for the design of natural preserves (e.g. SLOSS): several small fragments of a single biota can be expected to support nested subsets of the species originally present or that would likely be retained in a single large preserve. Even more sobering are arguments raised which suggest that the faunas of preserves established in different habitats within the same biome might be expected to converge in composition via selective extinction.
Biological Journal of the Linnean Society – Oxford University Press
Published: May 1, 1986
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera