Are Amur leopards growing in numbers?

2.04.2013

We are glad to hear the recent Amur leopard census results announced by WWF (http://www.wwf.ru/resources/news/article/eng/10964), but we would not say that the results are sensational.

The 2013 census was conducted following a traditional methodology based on measuring print size. Interpreting numbers of leopards from track counts is much more difficult than for tigers. Tigers are strictly territorial, so tracks of a given size within a given area can be assumed to be one individual with some high probability. Leopards in Southwest Primorye appear to not be territorial (based on WCS’s studies of radiocollared leopards) which means that two or more females or males could be using the same space. Over the last 14 years there are heated debates among Russian specialists about how to count leopards. Nearly every survey coordinated by Dmitry Pikunov has led results in estimates of 23-33 leopards. Vladimir Aramilev has coordinated two surveys – one in 1998 (40-44 leopards), one in 2000 (48-50), and Sergei Aramilev has coordinated one in 2013 (48-50).

We suppose WWF’s press release uses Pikunov’s estimates from 2007 to suggest a change in population size, when in fact the difference is one in methodology (or more precisely, who and how is interpreting the data). If you use the data from Vladimir Aramilev’s last survey (2000) there has been absolutely no change in the population size for 12 years.

Given the problems of the method, and the general problems of sampling rare, elusive carnivores, it is simply impossible to count numbers of leopards with such precision. 48-50 leopards suggests 49 +- 1. Simply impossible to have such certainty.

Moreover, carnivore populations grow slowly. For a population of leopards to increase 1.5 times in 5 years, a yearly growth rate of 9% is required. Such a high growth rate is likely possible only when leopard populations are small relative to prey populations, and they are free of mortality factors – conditions that were unlikely during the past 5 years in Southwest Primorye. So biologically it is highly unlikely (nearly impossible) that this population could increase so quickly.

In our opinion, the Amur leopard population in Southwest Primorye remains stable, but the final decision could be made only after an accurate comparison of the original data from the 2013 census with the one from the 2007 census.

By expressing our doubts regarding the increase in leopard population, we do not wish to paint a grim picture of the current situation and thereby minimize the effectiveness of all leopard conservation measures taken by our conservation community. Instead, we agree that there is no reason to let down our guard, regardless the census results, because 30, 40 and even 50 is still a critically small number for long term persistence of Amur leopard population. We just do not want the ordinary people and the government be misled by the press release into thinking that there is no need to protect this animal anymore.

 

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