Factors affecting the recovery of Mexican wolves in the Southwest United States

Recovering and maintaining large carnivore populations is a global
conservation challenge that requires better knowledge of the factors
affecting their populations, particularly in shared landscapes (i.e.,
non-protected areas where people occupy and or utilize the land). The
Mexican wolf (Canis lupus baileyi) is an endangered wolf subspecies being
recovered on shared landscapes in the Southwest United States and Mexico.
We used data from the U.S. program to model population growth, evaluate
the impact of management removal and illegal killing relative to other
demographic factors, and test hypotheses about factors influencing rates
of management removal and illegal killing. From 1998–2019, the population
growth averaged 12% per year. Rates of natural reproduction, illegal
killing, and other mortality remained consistent over the 22 years; while
releases, translocations, and management removals varied markedly between
two time periods, phase 1: 1998–2007 and phase 2: 2008–2019. The number of
wolves removed for conflict management was higher during phase 1 (average
~13 per year, rate = 24.8%) than phase 2 (average of ~5 per year, rate =
5.2%). This decrease in management removal resulted in the wolf population
resuming growth after a period of population stagnation. Two factors
influenced this decrease, a change in policy regarding removal of wolves
(stronger modeling support) and a decrease in the number of captive-reared
adult wolves released into the wild (weaker modeling support). Illegal
mortality was relatively constant across both phases, but after the
decrease in management removal, illegal mortality became the most
important factor (relative importance shifted from 28.2% to 50.1%).
Illegal mortality was positively correlated with rates of reintroduction
and translocation of wolves and negatively correlated with the rate of
management removal. Synthesis and applications. Using management removal
to reduce human-carnivore conflict can have negative population impacts if
not used judiciously. Recovering and maintaining carnivore populations in
shared landscapes may require greater tolerance of conflict and more
emphasis on effective conflict prevention strategies and compensation
programs for affected stakeholders.