8/12/2019 Abundance as Conservation Value

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Abundance as a conservation value

K E N T H . R E D F O R D, JO E L BE R G E R and S T E V E Z A C K

European colonists described an abundance of spawning river herring Alosa pseudoharengus in north-eastern UScoastal waterways in such multitudes as is almostincredible, pressing up such shallow waters as will scarcepermit them to swime [sic] (Wood [ 1634 ] 1977 , in Hallet al.,2012 ).

A curious thing has happened to conservation biology.Many of us were inspired by our experiences withlarge groups of wild animals be they in ocks, herds, orschools and in many case drawn to conservation as aprofession because of such experiences. And we havebeen increasingly educated through the work of historicalecologists on sliding baselines about how the abundance weencountered in our youth was nothing compared to theabundance of decades or centuries ago. Yet the discipline weembrace rarely considers abundance but instead has focusedmuch of its attention and passion on loss, rarity, endanger-ment, minimum viable population sizes, and minimum viable conservation areas.

Lost in this focus on the rare and endangered is attentionto that phenomenon that inspired many of us abundance.Abundance of species was a part of the experience of Europeans in many of the lands they settled. Not only havewe had ample experience with abundance but also with thespeed at which it can be lost: the collapse of Americanchestnut Castanea dentata that went from one of the mostabundant trees in the north-eastern USA to extinct in amatter of decades. Or the passenger pigeon Ectopistesmigratorius and North American bison Bison bison both of which collapsed from populations of tens of millions toeither extinct or a few hundred animals. More recently wehave come to understand the nature of the collapse of onceincredibly abundant marine species, from oysters to seaturtles to cod and river herring (Jackson et al., 2011).

These collapses are not just historical but have beenoccurring recently all around the world. The Madagascarradiated tortoise Astrochelys radiata was considered one of the world s most abundant tortoises and but is now almostextinct (Hudson, 2011). A similar pattern has been seen inrecent collapses of once abundant Asian vultures, caribou,

forest elephants, sharks and the European horse chestnut Aesculapius hippocastanum. But despite evidence both fromhistory and contemporary experience the conservationcommunity has concentrated on species that are already endangered and has not seriously considered still abundantspecies to have a value for conservation.

When we refer to abundance wemean not just the overallnumber of individuals but also the diversity of individualswithin a group. Evidence shows that there is a great deal of variation between individuals within large populations andthat this variation can be of signi cant behavioural andecological import (Hutchinson, 2008 ; Redford & Feinsinger,2001 ). Abundance is not only lots of the same but lots of diff erences as well.

We suggest there are four major reasons for conserva-tionists to care about the phenomenon of abundance.Firstly, wildlife in abundance, sometimes referred to aswildlife spectacles, helps inspire us and builds connectionswith thenatural world. Numerous travel agencies and mediaorganizations advertise the chance to experience or seewildlife in abundance, be it amingos, coral reef sh, baldeagles, monarch butter ies or wildebeest. Many of thesescenes are the ones that inspire conservationists and theirsupporters.

Secondly, abundance is itself an ecological feature thatmaintains other species including humans and ecosys-tems (Gaston, 2011). Examples arenumerous and reasonably well-documented, including forest elephants as seeddispersers, mound-building termites structuring commu-nities, bees as pollinators, sh as sources of human food andconveyors of marine nutrients inland, and wolves indirectly as ecosystem engineers through trophic-level interactions.

Thirdly, and increasingly well understood, abundantspecies provide many vital ecosystem services on whichnature and we rely. These include water ltration by oysters(Ermgassen et al., 2013), nutrient transport by salmon and

river herring (Gende et al., 2002 ; Hall et al., 2012 ), nutrientcycling and herbivory by wildebeest (Holdo et al., 2006 ) andocean mixing by a variety of organisms from krill to sh(Kerr, 2006 ).

Finally, it seems likely that it is easier in cost, and inmanagement eff ort, to maintain abundance in wildlifepopulations than it is to keep once abundant and now rarespecies from extinction. Abundance is a buff er fromperturbation whereas rarity is perpetual vulnerability.

In the face of these strong reasons why has abundancenot become an explicit conservation value? Strong argu-ments have been made in a set of important papers by

KENT H. R EDFORD Archipelago Consulting, Irvington NY 10533 USA. E-mailredfordkh@gmail.com

JOEL BERGER Department of Organismic Biology and Ecology, University of Montana, Missoula, Montana, USA

STEVE ZACK Wildlife Conservation Society, Portland, Oregon, USA

2013 Fauna & Flora International, Oryx , 47(2), 157158 doi:10.1017/S0030605313000331

8/12/2019 Abundance as Conservation Value

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