Fire plays a key role in grasslands, determining the distribution and evolution of species and boundaries with neighboring ecosystems. Evidence of community-wide responses to fire is largely based on ...taxonomic and functional descriptors, while the phylogenetic dimension is overlooked. Here we evaluated how the taxonomic and phylogenetic structure of grassland plant communities responded to a time since fire (TSF) gradient. We sampled 12 communities in Southern Brazil under varying TSF and calculated taxonomic species richness (S) and dominance (D), phylogenetic diversity (PD), and mean phylogenetic distances (MPD). We used Structural Equation Models to test the relationships between the environmental gradient and community descriptors. Communities with longer TSF presented higher PD and MPD but lower species richness and increased taxonomic dominance. These sites were dominated by monocots, specifically C4 grasses, but also presented exclusive clades, whereas recently-burned sites presented lower taxonomic dominance and more species distributed in a wider variety of clades. Our results indicate that these scenarios are interchangeable and dependent on fire management. Fire adaptation was not constrained by phylogenetic relatedness, contrasting with previous findings for tropical savannahs and indicating that temperate and tropical non-forest ecosystems from South America respond differently to fire, possibly due to different evolutionary histories.
The biodiversity loss resulting from rising levels of human impacts on ecosystems has been extensively discussed over the last years. The expansion of urban areas promotes drastic ecological changes, ...especially through fragmentation of natural areas. Natural grassland remnants surrounded by an urban matrix are more likely to undergo disturbance events. Since grassland ecosystems are closely related to disturbances such as fire and grazing, grassland plant communities, pollinators, and their interaction networks may be especially sensitive to urban expansion, because it promotes habitat fragmentation and modifies disturbance regimes. This work evaluated the effect of the level of urbanization and recent history of fire disturbance on grassland plants communities and plant-floral visitor mutualistic networks. We sampled plant communities and floral visitors in 12 grassland sites with different levels of urbanization and time since the last fire event. Sites with higher levels of urbanization showed higher values for plant species richness, floral visitor richness, and network asymmetry. All sampled networks were significantly nested (with one exception), asymmetric, and specialized. In addition, all networks presented more modules than expected by chance. The frequency of fire disturbance events increased with the level of urbanization. Since grassland ecosystems depend on disturbances to maintain their structure and diversity, we inferred that the history of fire disturbance was the mechanism behind the relationship between urbanization and our biological descriptors. Our findings highlight the importance of small and isolated grassland remnants as conservation assets within urban areas, and that the disturbance events that such sites are submitted to may in fact be what maintains their diversity on multiple levels.
Parturition is a key process of mammalian reproduction that is rarely documented in New World monkeys because it often occurs at night. However, diurnal births have been recorded in several species. ...In howler monkeys (
Alouatta
spp.) they have often been observed during prolonged resting periods. Similarly, infanticide is a behavior observed quite infrequently. Infanticide in howler monkeys is often inferred from infant deaths or disappearances after group takeovers by nonresident male(s). Here we report the first observation of parturition and birth-related behaviors in the brown howler monkey (
Alouatta guariba clamitans
) and the likely attack on the infant that caused its death. The mother was a multiparous female that lived in a ca. 3-ha Atlantic forest fragment in southern Brazil with nine group mates. The behavior (“all occurrences”) sampling method was used to record birth-related behaviors and social interactions. The parturition occurred during the day of 27 October 2013 during a feeding session. The female showed no sign of contraction or birth delivery posture. Parturition began apparently after matrix rupture and release of the amniotic fluid. Expulsion of the newborn occurred between 1 and 3 min later (the exact moment of delivery was not observed). Then, the female held and licked the newborn and began to ingest the placenta and the umbilical cord. The other group members continued feeding and had no interaction with the parturient during the preparturition and parturition events. The infant died ca. 35 days later as a consequence of injuries to his forehead and face, potentially caused by a conspecific bite. Because the adult and subadult males chased the female in the day that the infant’s wounds were detected, we believe that one of them might have been the aggressor. We discuss this putative case of infanticide in light of the potential motivation of each male.
Grassland ecosystems are evolutionarily linked to disturbances such as grazing and fire. These disturbances define grassland plant communities and habitat heterogeneity, which influence animal ...communities. We evaluated the influence of fire disturbance on plant and bird communities and on habitat structure by sampling grassland fragments with different time elapsed since the last fire event. Habitat structure was sampled using plant life forms and abiotic variables and birds were sampled through point counts. We recorded 862 bird individuals from 70 species. Intermediately-burnt sites harbor higher habitat heterogeneity and plant species richness in comparison with recently or long-burnt sites. Bird abundance and taxonomic diversity decreased linearly as time since fire increased. Finally, time since fire influenced the relative distribution of plant life forms and bird food guilds. Our results indicate that fire management should be included in the framework for conservation and sustainable use of grasslands, because it promotes habitat heterogeneity and diversity. To maintain habitat heterogeneity and the related habitat-specific bird species and functional groups, conservation efforts should maintain grassland patches under different management intensities and frequencies on a landscape level. However, studies focused on determining the periodicity with which fire management should be used are still lacking.
•Post-fire successional stages have unique sets of species.•Fire suppression reduces species richness but may increase beta and gamma diversity in the long run.•Grasslands under long-term fire ...suppression shift towards different ecosystem states.•Conservation must include fire to maintain representative sets of grassland species.
Fire is among the major forces shaping patterns in nature. Although sometimes it is only acknowledged for its destructive power, it was one of the evolutionary drivers that produced present-day species and biome distributions, being inextricably linked to fire-prone ecosystems such as grasslands. Knowing how fire influences grassland biodiversity is therefore fundamental to conserve it. Here we analyzed the taxonomic and functional structure of grassland plant communities from Southern Brazil under different post-fire successional stages. We sampled 12 sites that were fire-suppressed for varying amounts of time (3 to 300 months), categorized in three post-fire stages: freshly-burnt (FB), intermediate-burnt (IB), and old-burnt (OB). We compared these stages regarding taxonomic composition, species richness, diversity (partitioned in different spatial components), and functional composition (based on plant life forms and metabolism). We sampled 307 plant species from 52 families. Species richness was lower in the OB stage, and did not differ between FB and IB stages. Species composition was markedly different between stages. Forty-five percent of the sampled species were exclusive to one post-fire stage, and only 23% were shared among them. Old-burnt sites share only up to 5% species with other stages and concentrated most of the trees and tussocks. Because long-term fire suppression allowed for the entry of different floristic elements in the community, taxonomic diversity (beta and gamma levels) was higher in old-burnt sites. Our results provide empirical evidence that fire suppression is likely to shift the fire-prone grasslands from Southern Brazil towards different ecosystem states. However, whether this process is leading towards a closed forest system or to a different system with coexisting grassland and forest elements, remains an open question. The sharp floristic differences and exclusive species in the different post-fire stages reinforce the need to include fire in the conservation framework for fire-prone grasslands.
Natural history collections (NHCs) contain valuable information that can be used in different fields of knowledge, and aid in the development of society, science, and technology. The role of curators ...and taxonomists in maintaining and improving biological collections is essential, as these are fundamental for the understanding of biodiversity. However, the role of taxonomists and the importance of NHCs to society have been undervalued in recent years. We, while attending a graduate program on collections at PUCRS, noted a gap in knowledge about scientific collections. Was this gap, which continued from our undergraduate to graduate years, a mere coincidence or widespread in biological science programs in Brazil? We queried 126 Brazilian institutions of higher education to assess the presence of courses related to natural-history collections and taxonomy. A total of 25 private and 37 public universities from 126 institutions searched, have a program of study in biological sciences in the curriculum on their websites. About 16% offer some course related to NHCs or taxonomy, and all of them are public institutions. Despite the budget cutting made by the Brazilian government that make it even more difficult to recognize NHCs and related areas, we believe that there should be more links among researchers from different areas and especially between the levels of basic and higher education, so that students are exposed to this subject early in their education. We, as Brazilian students, believe that more information on NHC-related issues and taxonomic subjects is urgently needed in biological science programs.
ABSTRACT Natural history collections (NHCs) contain valuable information that can be used in different fields of knowledge, and aid in the development of society, science, and technology. The role of ...curators and taxonomists in maintaining and improving biological collections is essential, as these are fundamental for the understanding of biodiversity. However, the role of taxonomists and the importance of NHCs to society have been undervalued in recent years. We, while attending a graduate program on collections at PUCRS, noted a gap in knowledge about scientific collections. Was this gap, which continued from our undergraduate to graduate years, a mere coincidence or widespread in biological science programs in Brazil? We queried 126 Brazilian institutions of higher education to assess the presence of courses related to natural-history collections and taxonomy. A total of 25 private and 37 public universities from 126 institutions searched, have a program of study in biological sciences in the curriculum on their websites. About 16% offer some course related to NHCs or taxonomy, and all of them are public institutions. Despite the budget cutting made by the Brazilian government that make it even more difficult to recognize NHCs and related areas, we believe that there should be more links among researchers from different areas and especially between the levels of basic and higher education, so that students are exposed to this subject early in their education. We, as Brazilian students, believe that more information on NHC-related issues and taxonomic subjects is urgently needed in biological science programs.
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Previous issue date: 2018-04-04
Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
Mutualistic relationships between plants and animals play a key role in ecological and;
evolutionary processes. These relationships are seen as complex networks of interaction,;
which present recurrent structural patterns and are severely threatened by anthropogenic;
factors. The objective of this work was to evaluate the influence of the isolation caused by;
urbanization on the interaction networks between plants and floral visitors. Twelve South;
Brazilian fragments were sampled in the metropolitan area of Porto Alegre, Rio Grande do;
Sul. Sampling was performed during spring and summer of 2016/17 in 1-hectare circular plots;
using the focal method (10 minutes observation / plant). We estimated the degree of isolation;
of the fragments by calculating the area covered by urban matrix in a buffer of 2000 meters;
around each plot. We performed a qualitative-quantitative sampling of vegetation as part of;
the explanatory data observed for the network patterns. To construct interaction matrices, we;
divide visitors into potential pollinators and non-pollinators. We construct quantitative;
interaction matrices for each fragment/plot by calculating the metrics available in the;
networklevel function of the bipartite package of the R program. We estimate the correlation;
between the logarithm of the urbanized area in a radius of 2000 meters and each network;
metric calculated with the generalized linear model. We sampled 1240 plants (182 species).;
The total abundance of floral visitors was 1840 specimens (94% potential pollinators). The;
richness of plant species was greater in areas more isolated by urbanization, which is due to;
the fact that these areas catch fire more frequently. The richness of visitors was also higher in;
these areas, which is due to a "bottom up" effect given by the increase in plant richness. The;
results suggest that networks increase connectance and nestedness (in more urbanized areas);
as a way of protection against the disturbance, increasing system stability. In addition, areas;
further away from urbanization allow a greater level of network specialization, since they;
have a greater range of niches. We conclude that these findings highlight the importance of;
investing in the conservation and maintenance of natural areas within large cities, although;
they may seem isolated in the midst of a dense urban matrix. These areas are still a good;
haven for wildlife and need to be kept intact.
As rela??es mutual?sticas entre plantas e animais desempenham um papel chave nos;
processos ecol?gicos e evolutivos. Estas rela??es s?o vistas como redes complexas de;
intera??o, que apresentam padr?es estruturais recorrentes e est?o severamente amea?adas por;
a??es antropog?nicas. Este trabalho teve como objetivo avaliar a influ?ncia do isolamento;
causado pela urbaniza??o nas redes de intera??o entre plantas e visitantes florais. Foram;
amostrados 12 fragmentos campestres na regi?o metropolitana de Porto Alegre, Rio Grande;
do Sul. A amostragem foi realizada durante a primavera e o ver?o de 2016/17, em parcelas;
circulares de 1 hectare atrav?s do m?todo focal (10 minutos de observa??o/planta). Estimamos;
o grau de isolamento dos fragmentos calculando a ?rea coberta por matriz urbana em uma;
?rea tamp?o de 2000 metros em torno de cada parcela. Realizamos um levantamento qualiquantitativo;
da vegeta??o como vari?vel explanat?ria para os padr?es de redes encontrados.;
Para construir as matrizes de intera??o dividimos os visitantes em potenciais polinizadores e;
n?o polinizadores. Constru?mos matrizes quantitativas de intera??o para cada fragmento,;
calculando as m?tricas dispon?veis na fun??o networklevel do pacote bipartite do programa R.;
Estimamos a correla??o entre o logaritmo da ?rea urbanizada em um raio de 2000 metros e;
cada m?trica de rede calculada com modelo linear generalizado. Foram amostradas 1240;
plantas (182 esp?cies). A abund?ncia total de visitantes florais foi de 1840 esp?cimes (94%;
potenciais polinizadores). A riqueza de esp?cies de plantas foi maior em ?reas mais isoladas;
pela urbaniza??o, o que se deve ao fato destas ?reas pegarem fogo com mais frequ?ncia. A;
riqueza de visitantes tamb?m foi maior nestas ?reas, o que se deve por um efeito ?bottom up?;
dado pelo aumento na riqueza de plantas. Os resultados sugerem que as redes aumentam a;
conect?ncia e aninhamento (em ?reas mais urbanizadas) como uma forma de ?driblar? o;
dist?rbio, aumentando assim a estabilidade do sistema. Al?m disto, ?reas mais afastadas da;
urbaniza??o permitem um maior n?vel de especializa??o das redes, pois possuem maior;
amplitude de nichos. Conclu?mos que essas descobertas destacam a import?ncia do;
investimento na conserva??o e manuten??o de ?reas naturais nas grandes cidades, embora;
possam parecer isoladas em meio a uma densa matriz urbana. Estas ?reas ainda s?o um bom;
ref?gio para a vida selvagem e precisam ser mantidas intactas.
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