Abstract Marginal reefs can provide meaningful information about the structure and dynamics of ecosystems under suboptimal environmental conditions. In addition to their different characteristics, these environments can also occur in urbanized areas. In this note, we characterize marine animal forests (MAFs) on turbid-zone reefs on an urban coast in the equatorial southwestern Atlantic. Overall, the sandstone ferruginous reefs (6-10 m depth) exhibited a flat topography and gentle slope (1-2 m above the seabed). Benthic cover is composed mainly of sponge gardens and ascidians. In addition, we found a low-relief coral carpet with only one massive reef-building coral (Siderastrea stellata) and Zoantharia. The ascidians and sponges had a higher diversity (at least 15 species) than the cnidarians (two species) in these forests. The main animals forming this seascape are weedy and stress-tolerant species adapted to challenging environmental conditions, such as swell waves, mesotidal regimes, moderate turbidity waters, and periodic burial. In this regard, these conditions and human impacts have shaped a unique MAF. Remarkably, the studied formations seem similar to high-latitude marginal reefs or low-latitude reefs under the influence of upwelling, which sustains soft corals and non-framework building coral communities along with sponges and ascidians. In particular, the shallow MAFs along the semi-arid coast of Brazil seem to lack some of the characteristics of low-latitude reefs under high sedimentation, whose structure was described as coral rubble within sedimentary matrices. This suggests that factors other than periodic burials and low light availability affected these MAFs. These overlooked forests are widespread in this area and have been neglected in studies, despite their richness (> 31 taxa) and valuable ecosystem goods and services. In the context of urbanized areas subject to climate change and pollution impacts, jetties, and dredging activities, it is necessary to consider these lush forests in impact assessments and conservation policies.

O presente trabalho teve por objetivo avaliar a ocorrência de resistência imune em cães, frente a infestações sucessivas por ninfas de Amblyomma cajennense. Para tanto, cinco animais foram submetidos a quatro infestações consecutivas por ninfas de A. cajennense em intervalos de quatorze dias. Foram aplicadas 50 ninfas em cada animal por infestação e os dados referentes aos períodos parasitários e não parasitários, foram registrados. As taxas médias de recuperação de ninfas ingurgitadas, verificadas nas sucessivas infestações foram de 52,0, 29,2, 9,6 e 12,8%, sendo observada uma redução significativa (p < 0,05) nesse parâmetro a partir da segunda infestação. O dia modal de queda das ninfas ingurgitadas em todas as infestações foi o 4º dia de parasitimo. As taxas médias de mortalidade de ninfas observadas no primeiro, segundo, terceiro e quarto desafio parasitário foram de, respectivamente, 3,6, 3,2, 2,0 e 2,8%, não havendo diferença significativa entre elas (p < 0,05). Não observou-se diferença significativa (p < 0,05) entre as taxas de ecdise reportadas para os exemplares recuperados nos sucessivos desafios parasitários. Esses resultados sugerem que a resistência adquirida nos cães parasitados afetou negativamente a taxa de recuperação das ninfas de A. cajennense inoculadas nesses animais, contudo não apresentou nenhum efeito sobre os demais parâmetros biológicos avaliados.

The present study aimed to evaluate the occurrence of immune resistance in dogs successively infested with Amblyomma cajennense nymphs. Five animals were submitted to four consecutive infestations with A. cajennense nymphs, at fourteen-day intervals. For each infestation, 50 nymphs were used per animal and data on the parasitic and non-parasitic periods were recorded. The average recovering rate of engorged nymphs in the successive infestations were 52.0, 29.2, 9.6 and 12.8%, respectively, with a significant reduction (p < 0.05) of this parameter from the second infestation onwards. The modal drop-off day of engorged nymphs was Day 4 of parasitism in all infestations. The average mortality rates of nymphs seen on the first, second, third and fourth infestations were 3.6, 3.2, 2.0 and 2.8%, respectively, with no significant differences among them (p < 0.05). In addition, no significant differences were seen among the ecdysis rates for specimens recovered from successive parasitic challenges. The study results suggest that the acquired resistance of infested dogs had a negative effect on recovery rate of A. cajennense nymphs; however, it did not affect the other biological parameters evaluated.