Genetic and ecological outcomes of Inga vera subsp. affinis (leguminosae) tree plantations in a fragmented tropical landscape

Planting of native trees for habitat restoration is a widespread practice, but the consequences for the retention and transmission of genetic diversity in planted and natural populations are unclear. Using Inga vera subsp. affinis as a model species, we genotyped five natural and five planted populations in the Atlantic forest of northeastern Brazil at polymorphic microsatellite loci. We studied the breeding system and population structure to test how much genetic diversity is retained in planted relative to natural populations. We then genotyped seedlings from these populations to test whether genetic diversity in planted populations is restored by outcrossing to natural populations of I. vera. The breeding system of natural I. vera populations was confirmed to be highly outcrossing (t = 0.92; FIS = -0.061, P = 0.04), with populations showing weak population substructure (FST = 0.028). Genetic diversity in planted populations was 50% less than that of natural populations (planted: AR = 14.9, HO = 0.865 and natural: AR = 30.8, HO = 0.655). However, seedlings from planted populations showed a 30% higher allelic richness relative to their parents (seedlings AR = 10.5, parents AR = 7.6). Understanding the processes and interactions that shape this system are necessary to provide ecologically sensible goals and successfully restore hyper-fragmented habitats. Future restoration plans for I. vera must consider the genetic diversity of planted populations and the potential for gene flow between natural populations in the landscape, in order to preserve ecological interactions (i.e. pollination), and promote opportunities for outcrossing

Contrasting bee pollination in two co-occurring distylic species of Cordia (Cordiaceae, Boraginales) in the Brazilian semi-arid Caatinga: generalist in C. globosa vs. specialist in C. leucocephala

In this study we compare the reproductive biology of Cordia globosa and C. leucocephala (Cordiaceae, Boraginales; formerly referred to Boraginaceae) to understand the functioning of the floral morphs and the relations with their effective pollinators. The species are synchronopatric, distylic, and self-incompatible. Though they share melittophilous traits, the main visitor and pollinator of C. globosa was the generalist and exotic bee Apis mellifera, while the only one of C. leucocephala was the oligoletic bee Ceblurgus longipalpis. These two latter species are restricted to the Caatinga of NE Brazil, contrasting with the wide distribution of Cordia globosa. While the fruit-set for C. globosa was high, independently if the pollen donor/stigma receptor was a pin (long-styled) or thrum (short-styled) individual, in C. leucocephala the fruit-set was low and occurred only when a thrum individual was the pollen donor. This raises the possibility of this species moving towards dioecy. The high natural fruit-set of C. globosa confirms the generalist bee as its effective pollinator. The low fruit-set after manual crosses in C. leucocephala may be due to low pollen viability. Additionally, the low natural fruit-set (two times lower than after crosses) may be related with the foraging behavior of the specialist pollinator.Neste estudo comparamos a biologia reprodutiva de Cordia globosa e C. leucocephala para entender a função dos orfos florais e as relações com seus polinizadores efetivos. As espécies são sincronopátricas, distílicas e auto-incompatíveis. Embora elas compartilhem atributos melitófilos, o principal visitante e polinizador de C. globosa foi Apis mellifera, abelha generalista e exótica, enquanto o de C. leucocephala foi a abelha oligolética Ceblurgus longipalpis. Essas duas últimas espécies são restritas à Caatinga do Nordeste do Brasil, contrastando com a ampla distribuição de C. globosa. Enquanto a formação de frutos de C. globosa foi alta, independente se o doador ou receptor de pólen era um indivíduo brevi- ou longistilo, em C. leucocephala a formação de frutos foi baixa e ocorreu apenas quando o doador de pólen era brevistilo. Este fato levanta a possibilidade desta espécie estar se movendo em direção à dioicia. A alta formação natural de frutos de C. globosa confirma a abelha generalista como seu polinizador efetivo. A baixa formação de frutos após cruzamentos manuais e C. leucocephala pode ser devida à baixa viabilidade polínica. Adicionalmente, a baixa formação natural de frutos (duas vezes menor que a de cruzamentos) pode estar relacionada com o comportamento de forrageamento do polinizador especialista

Markedly declining reproductive functional diversity of food plants in the world's largest tropical country despite rapid cropland expansion

Cropland intensification in tropical regions is usually associated with agricultural commodity expansion that penalizes the species diversity and environmental services of natural ecosystems. However, the extent to which cropland expansion affects the reproductive functional diversity of crop arrangements remains poorly investigated. Here we examine the agricultural development of a leading agricultural producer and megadiverse country (Brazil) over the last six decades to understand the effects of agricultural expansion on the reproductive functional diversity of crops, particularly those bearing specialized traits. We used the FAO database, which provides annualized information on crop production from 1961 to 2018. Cultivated species were classified according to their reproductive traits and levels of dependence on biotic pollination, used as indicators of functional diversity. Our results show that cropland areas in Brazil expanded by 201.3% from 1961 to 2018. In particular, pollinator‐dependent crops expanded over this period by 305.2% compared to 125.3% in non-dependent crops. Expansion of monoculture farmland was remarkable, comprising 88% of the entire agricultural cropland acreage in 2018, 45% of which was represented by soybean. Additionally, cropland expansion was related to a reduction in functionally diverse crop species, which was most intense for those with specialized reproductive traits. These results indicate a threat to a diversified food production system and its resilience, given the impacts of cropland expansion on native biodiversity and the reduction in pollination services for many crops. We argue that agroecosystems in Brazil require sustainable, pollinator-friendly agricultural practices to maintain or enhance a nutritionally diversified food production system. Integrated practices that sustain agricultural cropland mosaics characterized by high reproductive functional diversity of the cultivated species can be a nature-based solution to protect natural pollinators and pollination services within a diversified food system

Data from: The loss of functional diversity: a detrimental influence of landscape-scale deforestation on tree reproductive traits

1. Agricultural activities such as crop production and cattle ranching are rapidly replacing forests worldwide, especially in the tropics. Resulting forest loss can adversely affect biodiversity in many ways, including trajectories of community reassembly, community composition, forest structural profiles, and taxonomic diversity. Yet, effects of forest loss on specific ecosystem functions remain limited. Processes closely linked with tree reproduction, such as pollination and seed dispersal are of paramount importance for many ecological functions in tropical forests. Disruption in these processes is known to delay or change forest regeneration, diversity, and structural dynamics. 2. To explore how reproductive and dispersal traits are being altered by landscape-scale deforestation, we surveyed and compiled trait data for tree communities in 20 tropical Atlantic rainforest remnants in northeastern Brazil, across a gradient of deforested landscapes, each retaining 3 to 93% forest cover. 3. The functional richness of reproductive plant attributes decreased as the amount of forest cover decreased, while divergence increased along the same gradient. Loss of forest cover disproportionately affected certain dispersal and reproductive attributes, with most heavily impacted functional attributes including: brief flowering duration, hermaphrodite sexual system, and zoochoric dispersal mode. We identified a clear threshold at 25-30% of forest cover, below which, reproductive attributes disappeared more quickly than expect from forest remnants. 4. Synthesis. Deforestation may impair tree community functional diversity, particularly by decreasing the number of functions and increasing certain functional reproductive attributes that are particularly successful in disturbed habitats. Under scenarios of extensive deforestation, changes to reproductive and dispersal trait profile of forest communities suggest that profound modifications in the availability of floral and seed resources are likely to be substantial. Such extensive changes to food supply of pollinating and dispersing animals suggest carry-over effects to the fauna of these important forest systems

The loss of functional diversity: a detrimental influence of landscape‐scale deforestation on tree reproductive traits

Agricultural activities such as crop production and cattle ranching are rapidly replacing forests worldwide, especially in the tropics. Resulting forest loss can adversely affect biodiversity in many ways, including trajectories of community reassembly, community composition, forest structural profiles and taxonomic diversity. Yet, effects of forest loss on specific ecosystem functions remain limited. Processes closely linked with tree reproduction, such as pollination and seed dispersal are of paramount importance for many ecological functions in tropical forests. Disruption in these processes is known to delay or change forest regeneration, diversity and structural dynamics. To explore how reproductive and dispersal traits are being altered by landscape-scale deforestation, we surveyed and compiled trait data for tree communities in 20 tropical Atlantic rainforest remnants in northeastern Brazil, across a gradient of deforested landscapes, each retaining 3%–93% forest cover. The functional richness of reproductive plant attributes decreased as the amount of forest cover decreased, while divergence increased along the same gradient. Loss of forest cover disproportionately affected certain dispersal and reproductive attributes, with most heavily impacted functional attributes including: brief flowering duration, hermaphrodite sexual system, and zoochoric dispersal mode. We identified a clear threshold at 25–30% of forest cover, below which, reproductive attributes disappeared more quickly than expect from forest remnants. Synthesis. Deforestation may impair tree community functional diversity, particularly by decreasing the number of functions. Under scenarios of extensive deforestation, changes to reproductive and dispersal trait profile of forest communities suggest that profound modifications in the availability of floral and seed resources are likely to be substantial. Such extensive changes to food supply of pollinating and dispersing animals suggest carry-over effects to the fauna of these important forest systems

Location of the study area.

<p>(A) Map of South America highlighting northeastern region of Brazil and original extent of Atlantic rain forest; (B) Original and remaining distribution of the Atlantic rain forest between Alagoas (AL) and Pernambuco (PE) states; (C) Study site map highlighting remnants of the Atlantic rain forest, <i>Inga</i> plantations, and urban areas.</p

Genetic substructure of planted and natural populations <i>Inga vera</i>.

<p>Structure plot generated using BAPS 5.3, displaying only significant admixture (<i>P</i><0.05) between planted and natural populations of adults (A and B) and seedlings (C and D). Number of genetic clusters (K) were assessed after five replicates.</p