The influence of habitat fragmentation on helminth communities in rodent populations from a Brazilian Mountain Atlantic Forest

Abstract

The influence of habitat structure on helminth communities of three sigomdontinae rodent species (Akodon cursor, A. montensis and Oligoryzomys nigripes) was investigated in forest fragments within an agricultural landscape in south-eastern Brazil. This is a pionner study correlating the occurrence of helminth species of rodent hosts with microhabitat characteristics. Rodents were collected from 12 fragments and in a continuous conserved area. Up to 13 nematode, three cestode and two trematode species were identified, and habitat fragmentation was found to have more influence on the helminth composition of O. nigripes compared to the other two rodent species. Fragmentation appeared to limit the development of some helminths' life cycles, e.g. with some species such as Trichofreitasia lenti, Protospirura numidica, Cysticercus fasciolaris and Avellaria sp., occurring mostly in areas with less anthropic impact. However, fragmentation did not seem to affect the life cycles of other dominant helminths, such as the trematode Canaania obesa, the nematodes Stilestrongylus lanfrediae, S. eta and S. aculeata, and the cestode Rodentolepis akodontis. The helminth community structure followed a nested pattern of distribution in A. montensis and O. nigripes. Stilestrongylus lanfrediae seemed to be more associated with dense understorey, C. obesa with open canopy and dense understorey, and Guerrerostrongylus zetta with organic matter on the ground. Their presence in each area may be explained by aspects of their life cycles that take place in the external environment outside the host.

Community structure and population dynamics of small mammals in an urban-sylvatic interface area in Rio de Janeiro, Brazil

“…The higher abundance of the rodents O. nigripes and A. cursor in areas with greater anthropic influence (peridomicile), also confirms the opportunistic nature of these species in relation to habitat occupancy, as previously observed in disturbed regions and along forest borders (Olifiers et al 2005, Vaz et al 2007, Geise 2012, Cardoso et al 2016, Gonçalves et al 2016. However, A. cursor showed more association with habitat variables, such as a close vegetation near the ground, which can provide shelter, protection against predators, and food resources (Dalmagro and Vieira 2005, Lima et al 2010, Melo et al 2013), a higher vegetation density in the understory and an open canopy, which are characteristic of open areas (Cirelli and Penteado-Dias 2003).…”

Testing for deterministic succession in metazoan parasite communities of marine fish

“…), but this pattern can be affected by habitat fragmentation, at least for the bat–helminth system and rodents (Cardoso et al . ; Warburton et al . ).…”

“…), fresh water fish (Carney & Dick ), rodents (Cardoso et al . ), birds (Calvete et al . ) and mammals (Krasnov et al .…”

“…The ecological theory of free-living organisms also supports the ecology of parasite communities, which helps to clarify potential patterns. A few examples include species-area relationships, local-regional species enrichment (Poulin & Morand 2004;Dove 2006), and the decay of similarity with distance in both vertebrate and invertebrate hosts (Poulin 2003;Oliva & Gonz alez 2005;Thieltges et al 2009), but this pattern can be affected by habitat fragmentation, at least for the bat-helminth system and rodents (Cardoso et al 2016;Warburton et al 2018). Island biogeography theory (MacArthur & Wilson 1967) has been applied to parasite communities under the premise that hosts are similar to islands, and larger hosts (as larger islands) harbor greater parasite richness (Kuris et al 1980).…”

“…Since the seminal study by Polyanski (1961) on the ecology of parasites of marine fish, studies of the structure of parasite communities have mainly addressed for nestedness patterns in marine fish (P erez-del Olmo et al 2008;Gonz alez & Oliva 2009;Timi et al 2010), fresh water fish (Carney & Dick 2000), rodents (Cardoso et al 2016), birds (Calvete et al 2004) and mammals (Krasnov et al 2005). However, no previous studies have applied or tested a hypothesis considering the theory of ecological succession to evaluate the development of parasite communities in marine fish species.…”