André Maurício Melo Santos

Landscape Attributes Drive Complex Spatial Microclimate Configuration of Brazilian Atlantic Forest Fragments

Habitat fragmentation imposes profound impacts on the tropical forest microclimate, but the microclimatic configuration of isolated forest patches and its implications for biodiversity persistence and habitat management are not clear. In this study we assessed a set of 10 aged (> 80 years) fragments (3.0 – 3,500 ha in size) of the Atlantic forest to examine to what extent fragment microclimatic attributes are correlated with distance to the nearest edge as frequently proposed in the literature. We used 129 sampling points and took a total of 516 measures of air temperature and humidity, vapor pressure deficit and light incidence to characterize the microclimate of forest fragments in terms of their relative deviation from the surrounding matrix. Fragments as a whole presented strong internal variation and strongly differed from the microclimate exhibited by the open matrix of sugar-cane fields. Distance to nearest edge, percentage of forest cover around the measurement point, percentage of edge-affected area, and geographical orientation of the nearest edge all proved to have minor effects on the microclimate of forest fragments. Conversely, we identified percentage of forest cover and fragment area as the most significant explanatory variables driving their microclimatic configuration: as forest cover increases at landscape scale, forest microclimate deviates less from the open matrix (a forest-mediated matrix buffering). Our results suggest that microclimatic conditions are spatially complex, as they do not correlate with the distance to the nearest forest edges; rather, they are driven by a forest-mediated buffering of the surrounding matrix that minimizes heat and humidity exchanges between forest and non-forest habitats, thus shaping the microclimatic signature of isolated forest fragments.

Seed predation by rodents and safe sites for large-seeded trees in a fragment of the Brazilian Atlantic forest

Seed predation by small rodents is an emerging theme in the ecology of modified landscapes. Here we investigate the role played by the small rodent Oryzomys oniscus as a seed predator of large-seeded trees in a large remnant of the Atlantic forest - the Coimbra forest (3,500 ha), Alagoas state, northeastern Brazil. O. oniscus was captured and identified by setting twenty 500 m long transects, each one composed of 25 traps 20 m apart. This procedure resulted in 483 trap-nights set during a 20-mo period. We used 692 seeds (>15 mm length) from ten local large-seeded tree species for the seed predation trials that basically consisted of three treatments: one seed on the ground freely accessed by vertebrates (unprotected seed), one seed totally protected by an exclosure, and one partially-protected seed (exclosure just for medium-sized and large vertebrates). O. oniscus was captured throughout the Coimbra forest including forest edges (76 captures) and interior areas (67), and this small rodent was responsible for all seed predation visually documented inside exclosures. A 24 hours period of seed exposition permitted elevated rates of seed removal and predation. Seeds were much more removed/predated beneath fruiting trees, but rates varied according to the level of seed protection--26.3% of predation among partially-protected versus 19.2% among unprotected seeds. Seeds suffered higher levels of seed predation/removal at the forest edge as well (up to 90%). In both habitats, most seeds (>84%) remained intact beneath trees without fruits, regardless of the level of seed protection. Our results suggest that O. oniscus may operate as an effective large-seed predator in forest fragments, in which adult trees without fruits constitute low resource spots and thereby provide, at least temporarily, safe sites for large seeds.

Are the vegetation structure and composition of the shrubby Caatinga free from edge influence

A influencia de borda, ou efeito de borda, leva a diversas alteracoes biologicas em paisagens fragmentadas. Embora muito estudada em ecossistemas florestais, a influencia de borda permanece desconhecida para a Caatinga. Baseada nas condicoes fisicas e biologicas da Caatinga arbustiva, nossa predicao a priori foi que este tipo de vegetacao nao sofre influencia de borda em termos de estrutura e composicao de especies. Nos amostramos arbustos, cactos e arvores em 20 parcelas de 200 m2 em bordas antigas (> 60 anos de idade) e interiores de um fragmento de 690 ha, parcialmente isolado e circundado por Opuntia ficus-indica. Altura das plantas, diâmetro ao nivel solo, densidade de individuos e riqueza e diversidade de especies foram estatisticamente iguais entre os habitats de borda e interior. A magnitude da influencia de borda variou de -0,027 a 0,027, indicando baixa importância ecologica da criacao de bordas para as variaveis analisadas. Adicionalmente, a similaridade floristica entre os habitats alcancou 90% e uma analise de componentes principais mostrou que a composicao de especies varia de forma similar na borda e no interior. O conjunto dos resultados indica que a vegetacao do fragmento estudado nao e ecologicamente afetada pela criacao de bordas e sugere que alteracoes nas condicoes fisicas e na disponibilidade de recursos apos a criacao das bordas sao insuficientes para eliminar plantas ja estabelecidas ou alterar o recrutamento e a sobrevivencia de novos individuos.

Growth of the tropical zoanthid Palythoa caribaeorum (Cnidaria: Anthozoa) on reefs in northeastern Brazil

In Brazilian reefs, zoanthids, especially Palythoa caribaeorum are fundamental for structuring the local benthic community. The objective of this study was to determine the growth rate of P. caribaeorum, and to assess the influence of the site (different beaches), season (dry and wet), location (intertidal or infralittoral zones), and human pressure associated with tourism. For one year we monitored the cover of P. caribaeorum in transects and focused on 20 colonies. We cut off a square (100 cm2) from the central part of the colony and monitored the bare area for four months in each season. The average growth rates varied from 0.015 and 0.021 cm.day(-1). The rate was homogeneous in all localities, and there was no influence from colony site, location, or touristic visitation, showing that the growth velocity may be an intrinsic characteristic of the species, with a strong genetic component. The growth rate of P. caribaeorum differed among months, and peaked in the first month after injury. The average cover varied from 6.2 to 22.9% and was lower on the reef visited by tourists. The present study corroborates the hypothesis that P. caribaeorum is important for coastal reef dynamics due to its fast and continuous growth.

Mass Extinction and the Disappearance of Unknown Mammal Species: Scenario and Perspectives of a Biodiversity Hotspot's Hotspot.

We aimed to determine the conservation status of medium- and large-sized mammals and evaluate the impact of 500 years of forest fragmentation on this group of animals in the Pernambuco Endemism Center, in the biogeographical zone of the Atlantic forest north of the São Francisco River in northeastern Brazil. Line transect surveys were performed in 21 forest fragments, resulting in a checklist of the mammals of the entire Pernambuco Endemism Center area. We ran a generalized linear model (Factorial ANCOVA) to analyze to what extent the vegetation type, fragment area, isolation, sampling effort (as total kilometers walked), or higher-order interactions predicted (a) richness and (b) sighting rates. To determine if the distribution of the species within the forest fragments exhibited a nested pattern, we used the NODF metric. Subsequently, we performed a Binomial Logistic Regression to predict the probability of encountering each species according to fragment size. Out of 38 medium- and large-sized mammal species formerly occurring in the study area, only 53.8% (n = 21) were sighted. No fragment hosted the entire remaining mammal community, and only four species (19%) occurred in very small fragments (73.3% of the remaining forest fragments, with a mean size of 2.8 ha). The mammalian community was highly simplified, with all large mammals being regionally extinct. Neither the species richness nor sighting rate was controlled by the vegetation type, the area of the forest fragments, isolation or any higher-order interaction. Although a highly significant nested subset pattern was detected, it was not related to the ranking of the area of forest fragments or isolation. The probability of the occurrence of a mammal species in a given forest patch varied unpredictably, and the probability of detecting larger species was even observed to decrease with increasing patch size. In an ongoing process of mass extinction, half of the studied mammals have gone extinct. The remaining medium-sized mammal community is highly simplified and homogenized. The persistence of these species in a forest patch is determined by their ability to adapt to a novel simplified diet, the efficient use of the surrounding matrix without being engulfed by the sink effect, and escaping hunting. Our results suggest that the 21st century medium-sized mammalian fauna of this region will comprise only four species unless strict conservation measures are implemented immediately and every forest fragment is effectively protected.

Comparisons of sexual reproduction in Carijoa riisei (Cnidaria, Alcyonacea) in South Atlantic, Caribbean, and Pacific areas

Soft corals show a wide variety of reproductive strategies, including both asexual and sexual reproduction which can influence macro-evolutionary processes. The octocoral Carijoa riisei has an ample geographical distribution in Pacific and southern Atlantic and also in Caribbean region. This species was considered invasive in Hawaii, and its capacity for rapid proliferation is recognized, but recent studies, however, have indicated that it appears to be native to the Indo-Pacific region. The present study examined the reproductive biology of C. riisei in the Atlantic basin. The results were then compared to previous studies of the same species from the Pacific (Hawaii) and Caribbean (Puerto Rico) regions to examine the hypothesis that the reproductive patterns of C. riisei populations are the same throughout its geographical distribution, independent of its native or non-native status. Samples were collected on a monthly basis from May/2007 to April/2008 at Porto de Galinhas (Pernambuco State, Brazil). This species was found to have similar reproduction patterns in Brazil, the Caribbean, and in Hawaii (a gonochoric reproductive pattern and continuous and asynchronous gamete release). The similarities of their traits contribute to its rapid proliferation and occupation of spaces left by other species, independent of its native or non-native status.

Biological Impacts of the Port Complex of Suape on Benthic Reef Communities (Pernambuco-Brazil)

ABSTRACT Costa, D.L.; Santos, A.M.; da Silva, A.F.; Padilha, R.M.; Nogueira, V.O.; Wanderlei, E.B.; Bélanger, D.; Gomes, P.B., and Pérez, C.D., 2014. Biological impacts of the port complex of Suape on benthic reef communities (Pernambuco–Brazil). The construction of Suapes port in 1979 divided a natural reef line into two reefs (Suape and Muro Alto) and generated changes in the hydrodynamics along the coast of Pernambuco State, Brazil. We compared the composition of the macrobenthic communities on the two reefs to determine how they were affected by the construction of the port. Two seasonal collections were made along each reef utilizing the band transect, totalizing 144 transects. Of 47 taxa found, 11 were exclusive to Suape and two to Muro Alto. The Suape reef demonstrated the greatest richness (F1,126 = 54.634, p < 0.001) and a significantly different faunal composition (analysis of similarity: r = 0.534, p < 0.001). Analyses (three-way, full factorial analysis of covariance) indicated that the reef and intertidal zone variables affected richness, whereas roughness and seasonality did not. The high intertidal zone of both reefs had greater roughness and lower richness and was significantly different from the other zones in relation to the fauna composition, confirming a two-zone intertidal zonation pattern (high and middle + low). Nodilittorina ziczac and Chthamalus bisinuatus characterized the high zone of the Muro Alto, and Protopalythoa variabilis and Petaloconchus varians characterized the same zone at Suape. The construction of the port altered the tidal cycles so that the Muro Alto reef now remains exposed for longer periods, resulting in diminished richness and marked differences in its faunal composition. The original reef was 11 km long with a homogeneous community, but its division by the construction of the port resulted in several impacts to the region, principally the creation of two distinct reefs in terms of the ecological parameters analyzed, with species such as the coral Favia gravida and the zoanthid Palythoa caribaeorum disappearing from the Muro Alto reef or the gastropod Littoraria nebulosa (recorded before the construction of the port), which was not found during the present study.