Conservation of the largest cervid of South America: interactions between people and the Vulnerable marsh deer Blastocerus dichotomus

Abstract

Wild ungulates, and particularly deer, can cause severe damage to commercial plantations, resulting in reduced tolerance of their presence by forestry producers. The marsh deer Blastocerus dichotomus, categorized as Vulnerable on the IUCN Red List, is declining throughout South America. A population of c. 500 individuals survive within a matrix of commercial plantations in the lower delta of the Paraná River, the southernmost stronghold for the species. Local forestry producers usually report that damage to plantations is attributable to marsh deer, thus justifying persecution of the species. Seventy-six forestry producers (representing c. 33% of the total plantation area of the lower delta) were interviewed using a semi-structured questionnaire to assess perceived levels of tree damage, associated economic losses, and attitudes towards the deer. Simultaneously, plantation stands were surveyed to quantify the actual tree damage caused by this ungulate. Seventy-six percent of producers reported damage to trees by deer (i.e. browsing, fraying caused by antler rubbing) but most of them perceived low levels of damage per property (median < 0.2%), with negligible economic effects. However, 5% of producers (all of them with ≤ 2 km2 in production, usually family enterprises) perceived high levels of damage and economic losses, and supported deer hunting as a management option. Field surveys indicated that damage caused by deer could be more severe than perceived by producers, although spatially confined within the landscape. Monitoring of damage perception by forestry producers, and compensation schemes to assist small producers are necessary for adequate management of this threatened marsh deer population.

Are tree plantations promoting homogenization of mammal assemblages between regions with contrasting environments?

“…Similarly, it is likely that some grassland or wetland species (e.g. the pampas fox and the marsh deer), although they can move or use the tree plantations (Iezzi et al, 2017(Iezzi et al, , 2020, need the presence of grasslands (or wetlands) in the landscape to survive and they are very unlikely to be recorded in tree plantations established in the Atlantic Forest region.…”

Diet of the marsh deer in the Paraná River Delta, Argentina—a vulnerable species in an intensive forestry landscape

“…In the lower Delta, foresters usually report damage to plantations attributable to marsh deer, with browsing on buds and leaves the most commonly reported damage to Salix spp. (Iezzi et al 2018). Consequently, foresters consider it necessary to minimize damage from deer to avoid monetary losses with wire fencing, electric fencing, or poaching (Iezzi et al 2018).…”

“…Perceptions of these radical producers are based on two premises: (1) damages to commercial trees due to deer action are high and widespread in this wetland, and (2) trees of commercial value are important components of the diet of this ungulate. Field surveys partially support the first premise, indicating that damage caused by deer could be more severe than perceived by producers (Iezzi et al 2018). The second premise, however, cannot be tested because information about the feeding habits of marsh deer in this wetland is lacking.…”

“…Marsh deer seems to have adapted to this drastic change in the habitat physiognomy, and its current presence in this wetland is mostly linked to landscapes under forestry production (Varela 2003;Pereira et al 2018). Although local forestry producers usually report damage (i.e., browsing, fraying caused by antler rubbing) to commercial trees by deer, only a minor fraction of these producers perceive high levels of damage and economic losses and support marsh deer poaching as a management option (Iezzi et al 2018). Perceptions of these radical producers are based on two premises: (1) damages to commercial trees due to deer action are high and widespread in this wetland, and (2) trees of commercial value are important components of the diet of this ungulate.…”

Stop draining the swamp: it's time to tackle wetland loss

“…Human use of wetlands can bring wildlife into conflict with people. Swamp deer in northern India (Paul et al, 2018), marsh deer in South America (Iezzi et al, 2018), and crocodiles in the Sundarbans (Das & Jana, 2018) have all been persecuted. Other species are affected by human-facilitated invasive species: the Vulnerable reticulated flatwoods salamander has declined as a result of feral swine invading its wetland breeding grounds (Jones et al, 2018).…”