Status of Large Terrestrial Vertebrates in the Monteverde-Arenal Bioregion, Northwestern Costa Rica

Abstract

Protected areas have been important in reducing tropical forest biodiversity loss. Costa Rica has been a model country in protecting forests and promoting conservation. However, many Costa Rican protected areas are surrounded by highly modified habitat and may be losing species, either because they are too small to support viable populations or are too isolated to allow for population connectivity. We used camera traps to study terrestrial mammal and terrestrial bird populations in the Monteverde-Arenal Bioregion of northwestern Costa Rica. We sampled core protected areas and nearby unprotected, fragmented habitats. Of 33 species historically found in the region, we detected 25. However, most species were rarely detected, and only five were found more than once per 30 days of camera time. The most commonly detected species represented major feeding groups, including obligate herbivores, omnivores, and obligate carnivores. Most ungulates were rare and may not have viable population sizes. However, a top predator, the puma (Puma concolor), was commonly detected. Fragmented areas had lower abundance and fewer species detected; a few species were not detected at all, even though some of them were abundant in the core protected areas. We suggest that conservation efforts are protecting some terrestrial mammals and birds, and there is a functioning food web. However, many species are either rare or extirpated, indicating the Monteverde-Arenal Bioregion is a partially defaunated landscape.

A proposal for practical and effective biological corridors to connect protected areas in northwest Costa Rica

“…In fact, viable jaguar populations may only occur in only two of the areas of this study: the reserves of the Guanacaste Conservation Area and the Central Volcanic Mountain Range (Sanderson et al 2002, SINAC 2018b, although our analysis indicates these are also too small to survive in the long-term (Thomas 1990). A recent camera study of the MAB found that jaguars were very rare (and probably non-viable) in that isolated (although relatively large, about 50,000 ha) conservation area (Zamzow et al 2018). However, if the sub-corridors proposed here were established and protected, they would increase connectivity, presumably increasing the combined population size in all protected areas from the Guanacaste region to the Central Volcanic Mountain Range (jaguar conservation unit 154 in Sanderson et al 2002).…”

“…Guanacaste and Santa Rosa NPs, SINAC 2018b) but is very rare or absent in other protected areas (e.g. MAB, Zamzow et al 2018). Therefore, if sub-corridor protection were to be initiated, this species could also be monitored in areas where it is currently absent or rare as a measure of whether our proposal was having some conservation success.…”

“…This habitat could potentially support species such as the jaguar, which have naturally low population densities and require large areas with limited human activity to sustain viable populations. Some large mammals are missing or rare in isolated protected areas within our study region (Zamzow et al 2018); often these mammals are species considered important for ecosystem functions, such as prey population regulation (e.g. top predators, Estes et al 2011) and seed dispersal (e.g.…”

“…On the ground, however, functional connectivity (in terms of ability of forest-dependent organisms to move through these corridors) is less than ideal since the two biological corridors in question are composed mostly of fragments (see results) of forest with little or no formal protection. Recent monitoring of fragmented lands surrounding the MAB indicates that many large mammals found in the parks and preserves are not utilising their habitat outside the protected areas (Zamzow et al 2018). Therefore, the MAB -which includes Arenal Volcano National Park, the Children's Eternal Rainforest, Monteverde Cloud Forest Biological Reserve, Santa Elena Cloud Forest Reserve and Alberto Manuel Brenes Biological Reserve -remains relatively isolated.…”

First Locality Record of Melanistic Oncilla (Leopardus tigrinus) in Monteverde, Costa Rica

“…The rarity of observations of melanistic oncillas in this region may, however, indicate that this is a random mutation rather than an adaptive advantage. While non-melanistic oncillas have been observed in recent mammal studies in the Monteverde Region (Zamzow et al 2018), observations are notably rare and much less frequently recorded than its more common Leopardus relatives and puma (Personal communication; JE Rogan unpublished data) and it is possible it was misidentified due to its strong resemblance to margay (Zamzow et al 2018). Further research efforts to gauge the frequency of melanistic oncillas in the area will be key to better understanding this incredible phenomenon in this elusive species.…”