Grazing by domestic herbivores has altered biodiversity worldwide. This practice has persisted throughout much of the Baja California peninsula since the 1530s, when the captains under Hernán Cortés first introduced livestock. Grazing intensity increased substantially in the 1800s and is now widespread across the peninsula. The ecological consequences of livestock grazing are well-documented in the southwestern United States. Experimental studies employing livestock exclosures have demonstrated both the long-term effects on plant and animal communities and the potential for ecosystem recovery following cessation of grazing. These studies consistently report higher abundance and diversity of small mammals within exclosures compared to grazed areas. To date, no comparable exclusion studies have been conducted on the Baja California peninsula. In the spring of 2023, we sampled 106 ha of tropical deciduous forest across three adjacent sites representing distinct grazing histories: a 2-year exclosure (45 ha), a 10-year enclosure (40 ha), and an unfenced control (21 ha). As expected, longer exclusion periods were associated with increased species diversity and community complexity. Balancing the economic importance of pastoralism with the conservation of native biodiversity remains a critical challenge for sustainable land management throughout the region.