Alexandra S. Pires

Influence of edge and fire-induced changes on spatial distribution of small mammals in Brazilian Atlantic forest fragments

The spatial distribution of small mammals in relation to distance from forest edges, before and after fire, was studied in Atlantic Forest fragments in Brazil. None of nine species was captured exclusively on either edges or forest interior. Before the fire only the rodents Akodon cursor and Oecomys con-color were captured more often at the edge than randomly expected. After the fire only A. cursor remained associated with edges; it had increased in number and penetrated farther than before into the forest fragments. The marsupial Micoureus demerarae became more restricted to the forest interior than randomly expected. These results suggest that small mammal species tolerant to habitat changes induced by edge effects and fire have better chances to survive in forest fragments.

Short-Term Success in the Reintroduction of the Red-Humped Agouti Dasyprocta Leporina, an Important Seed Disperser, in a Brazilian Atlantic Forest Reserve

Reintroduction is an increasingly important tool to restore local extinctions and ecological interactions. Evaluating the success of reintroduction projects allows conservationists to learn from previous experience. Here we report on the reintroduction of agoutis, Dasyprocta leporina, to a Brazilian Atlantic Forest reserve in order to (1) determine the short-term status of the reintroduction; (2) describe and evaluate the management procedures that contributed to reintroduction success; and (3) identify the fruits and seeds consumed and buried by the agoutis, as an indication of their role in restoring ecological processes. We captured and tagged 21 adult individuals from a semi-captive population and reintroduced four males and seven females. One male died and almost all individuals lost weight (range=0-620 g; n=11) during quarantine (median=133 days; range=67–243 days; n=20). Six males and three females died, but the others gained weight during acclimatization (range=150–260 g; n=5). Individuals abandoned the food supplement up to 87 days after release, establishing home-ranges at least three times larger than in natural populations of agoutis. The estimated annual survival rate was 0.83, and 10 nature-born cubs were observed. The reintroduction was considered successful in the short-term. Among the main recommendations for future reintroductions, we suggest the reduction of quarantine and the maintenance of acclimatization periods, with structural improvements for both. Agoutis were seen eating fruits and seeds of 10 species and burying seeds of three of them. The buried seeds are from zoochoric large-seeded trees, thus enhancing recruitment in a disperser-impoverished forest.

Preventing injuries caused by radiotelemetry collars in reintroduced red-rumped agoutis, Dasyprocta leporina (Rodentia: Dasyproctidae), in Atlantic Forest, southeastern Brazil

Reintroduction has been recognized as a powerful conservation tool, but in order to ensure its success, animal monitoring is highly recommended. One way to monitor released animals is to put radiotelemetry collars on them. These devices, however, can harm the subjects, causing serious wounds. Our objectives in this work were to describe the injuries caused by a radiotelemetry collar model on reintroduced agoutis and to propose modifications to it. We equipped agoutis with TXE-311C radio collars (Telenax Wildlife Telemetry) before releasing them in the wild. They acquired serious wounds and one animal died. We then modified the collar structure to reduce its width and retention of water. After these modifications, the injuries did not occur again. As reintroduction is an expensive conservation strategy, any improvement that maximize its probability of success is important. We believe that the improvements we propose here have the potential to enhance the success of reintroductions and to increase animal welfare. This recommendation is more important when captive animals are re-introduced, because they tend to have lower immunity, particularly when they are released in rainy habitats.

Credit of ecological interactions: A new conceptual framework to support conservation in a defaunated world

Abstract As defaunation spreads through the world, there is an urgent need for restoring ecological interactions, thus assuring ecosystem processes. Here, we define the new concept of credit of ecological interactions, as the number of interactions that can be restored in a focal area by species colonization or reintroduction. We also define rewiring time, as the time span until all the links that build the credit of ecological interactions of a focal area have become functional again. We expect that the credit will be gradually cashed following refaunation in rates that are proportional to (1) the abundance of the reintroduced species (that is expected to increase in time since release), (2) the abundance of the local species that interact with them, and (3) the traits of reintroduced species. We illustrated this approach using a theoretical model and an empirical case study where the credit of ecological interactions was estimated. This new conceptual framework is useful for setting reintroduction priorities and for evaluating the success of conservation initiatives that aim to restore ecosystem services.

Medium and large-sized mammals of the Reserva Ecológica de Guapiaçú, Cachoeiras de Macacu, RJ

Medium and large-sized terrestrial mammals develop important functions in ecosystems maintenance. However, this group is the most vulnerable to local extinctions, through habitat loss or hunting. This study inventoried the community of medium and large mammals in the Reserva Ecologica de Guapiacu (REGUA), Cachoeiras de Macacu, RJ, providing data on species composition, richness and abundance. Species were registered through the use of camera traps, sign survey and visual encounters on pre-existing trails and roads. The study was conducted from January to October 2012, with each month considered as a sample unit. An effort of 1568 cameras-day and 120 km traveled, resulted on 302 records of 22 species of medium and large-sized mammals, belonging to eight orders. This value corresponds to more than three-quarters of the richness described from this group in the Atlantic Forest of Rio de Janeiro state. Five species are under some level of regional, national or global threat. Three game species, Pecari tajacu, Cuniculus paca and Dasyprocta leporina were abundant in the area. The observed richness was comparable to that found in other studies conducted in rain forests. Thus, for its high number of species, including those under some degree of threat, we conclude that REGUA is an important area to mammal conservation, especially in the Atlantic Forest of Rio de Janeiro state.

Effects of howler monkey reintroduction on ecological interactions and processes: Effects of howler monkey reintroduction

Rewilding has been an increasingly popular tool to restore plant-animal interactions and ecological processes impaired by defaunation. However, the reestablishment of such processes has seldom been assessed. We investigated the restoration of ecological interactions following the reintroduction of the brown howler monkey (Alouatta guariba) to a defaunated Atlantic forest site. We expected the reintroduction to restore plant-animal interactions and interactions between howlers and dung beetles, which promote secondary seed dispersal. We estimated the number of interactions expected to be restored by the reintroduction to provide the baseline interaction richness that could be restored. We followed the reintroduced howler monkeys twice a week for 24 months (337 hours total) to assess their diet. We used howler monkey dung in secondary seed dispersal experiments with 2484 seed mimics to estimate the removal rates by dung beetles and collected the beetles to assess community attributes. We compared the potential future contribution of howler monkeys and other frugivores to seed dispersal based on the seed sizes they disperse in other areas where they occur. In 2 years, howler monkeys consumed 60 animal-dispersed plant species out of the 330 estimated. Twenty-one dung beetle species were attracted to experimentally provided dung; most of them were tunnelers, nocturnal, and large-sized (>10 mm). On average 30% (range 0-100%) of the large seed mimics (14 mm) were moved by dung beetles. About 91% of the species consumed by howlers (size range 0.3-34.3 mm) overlapped in seed size with those removed by dung beetles. In our study area, howler monkeys may consume more large-seeded fruit species than most other frugivores, highlighting their potential to affect forest regeneration. Our results show reintroductions may effectively restore ecological links and enhance ecological processes.

Unusual branching in the palm Euterpe edulis Mart

The unusual development of branches along the stem of Euterpe edulis is described for the first time. Branches originated at 2 to 190 cm from the ground. Ramified individuals and branches were able to produce reproductive structures and some branches produced roots. A plausible cause for the observed anomaly could be genetic problems due to small population sizes. The better agreement of this process can have a positive effect in the harvest of the heart of palm through the artificial induction of sprouts, what would prevent the death of the individual.

Resting sites of opossums (Didelphimorphia, Didelphidae) in Atlantic Forest fragments

We report the type and pattern of use of resting sites used by 14 radio-tracked opossums. Philander frenatus rested in natural structures but also on spherical structures of dry leaves, probably built by them. Caluromys philander and Marmosa paraguayana rested at forest canopy preventing nest type identification. More than half of the resting site locations of each radio-tracked individual were in a single resting site. The repeated use of resting sites in the study area might be a strategy to stay close to resources and a protection against adverse weather conditions, predators and/or competitors.

Species richness and density evaluation for plants with aggregated distributions: fixed vs. variable area methods

Aims Knowledge of species richness is of prime importance to both basic and applied aspects of ecological studies. However, quantifying plant species richness in the tropics is potentially time-consuming because of high species diversity. Plant species richness estimates are also frequently biased, because many rare species are not detected. to address these problems, the use of a variable area method has been proposed as an alternative to fixed area methods, but its applicability to plants with aggregated distributions has been questioned based on simulation studies. We use empirical data to compare the efficiency and accuracy of a variable area method and a fixed area method for estimating species richness, density and basal area for plants with aggregated distributions, using palms as a model taxon. Methods Adult palms were sampled in twenty 10 × 30 m transects in an Atlantic Forest in Rio de Janeiro state, Brazil. All individuals were considered in the fixed area method, while in the variable area method only the first six adults in each transect were sampled; in this case, transect length was defined according to the distance of the sixth adult from the beginning of the transect. When fewer than six individuals were observed in a given transect, transect length was extended up to 50 m to search for additional individuals. the efficiency of both methods was compared based on species rarefaction curves, using the chao 1 statistic (for abundance data). For each species we calculated mean density per transect and basal area, according to each sampling method. Sampling effort in terms of the number of individual plants and the area necessary to characterize maximum species richness in each sampling method, as well as mean time taken to sample a single transect, were compared as measures of efficiency. Important findings An accurate estimate of species richness was achieved using both methods, but in the variable area method, a quarter of the number of individuals and half the area was sufficient to characterize maximum species richness. Density and basal area did not differ between methods for any of the species studied. In the fixed area method sampling effort was 90 min per transect, whereas in the variable area method it was 30 min per transect. the variable area method, with its faster assessment of palm species richness, should facilitate greater spatial representativeness by making it easier to sample a larger number of plots at different spatial scales. We thus find sufficient evidence to recommend the variable area method for rapid and robust evaluations of species richness for palms with aggregate distributions, as well as for other plants with similar spatial patterns, in tropical forests.