Agricultural Matrix Research Articles

Landscape heterogeneity of peasant-managed agricultural matrices

Management practices, environmental and social factors shape complex agricultural landscapes. In turn, the structure of such landscapes impacts biodiversity conservation, for instance, by mediating wildlife migration between agricultural and habitat patches and thus determining the persistence of metapopulations. Landscape ecology has used heterogeneity metrics and has systematically examined how they change with grain size and landscape extent to formally characterize a landscape, its structure and potential role in the persistence of wild metapopulations. These metrics provide valuable information regarding the landscape connectivity, patch diversity and shape. However, heterogeneity metrics have rarely been applied to tropical or subtropical, peasant-managed landscapes, even though this type of landscape occupies most of the agricultural surface in or near biodiversity hotspots. We focus on a peasant-managed agricultural landscape in Oaxaca, Mexico. For this landscape we mapped and quantified the land-use classes (48 % for agricultural land use, with kappa = 88.85 %). We also calculated heterogeneity metrics and examined their response to changes in grain and extent scales. This allowed us to further understand the structure and conservation potential of the agricultural matrix in this type of landscape, in comparison with other agricultural landscapes in Eastern North America. Our results also enabled us to recommend specific landscape metrics such as Largest Patch Index, Shape Index, and Interspersion & Juxtaposition Index, for different types of studies involving the link between agricultural matrices and conservation. We conclude that this type of agricultural matrix is ideal to pursue joint agricultural and conservation strategies in an integrated landscape.

ECONOMIC ANALYSIS OF THE AGRICULTURAL POLICY OF THE EGYPTIAN RICE CROP

Agricultural production is not sufficient for the needs and desires of individuals, which led to the trend towards import to fill the deficit in agricultural production, especially in strategic crops such as rice, and the Egyptian agricultural policy to encourage farmers to grow these crops such as rice and some other crops by setting price levels for the Achieving local Production of these crops to reduce the deficit in The balance of agricultural trade. The problem of research is that the government directly or indirectly intervenes in some policies in the supply of rice crop, which may be unfavorable to the producer. This has led to price imbalances between local and world prices. The aim of this research is to study the impact of agricultural policies on the cost items of rice crop and to show the impact of policies on the revenues and value added using the policy Analysis matrix (PAM). The research was based on published and unpublished data from government agencies and the world bank. The research used descriptive and quantitative statistical analysis methods and economic indicators of the agricultural policy analysis matrix to analyze the data and achieve the study objectives. The research found that the nominal protection coefficient of the output reached 0.67 Throgle the Study Period (2000-2017), which means that producers pay implicit taxes of about 0.33 for the average period, as a result of not obtaining the real prices of their production, because the local farm price per ton of rice is lower than the border price in the years of study. This means the absence of a fair production policy and the existence of implicit taxes borne by rice producers in general, and the support and protection of commodity prices in the domestic market in favor of the consumer. As for the protection coefficient of production requirements, it reached 0.9 during the study period (2000-02017) and its value was less than the correct one, which indicates that the cost of inputs at local prices is lower than that of the border price, which means that the state provides support to farmers for production requirements. However, it should be noted that this subsidy is low and not more than 0.10 against the greater proportion of implicit taxes borne by farmers. The effective protection coefficient was 0.66, which implies the existence of implicit taxes to be borne by rice producers. Emphasizes the comparative advantage Egypt enjoys in producing the rice crop due to the lower cost of producing it locally than the cost of importing it. The study recommended the establishment of marketing systems to ensure the product a profit margin that reduces the taxes incurred by rice farmers and the establishment of a price balancing fund to compensate farmers, work to support the production requirements of rice farmers, attention to scientific research to provide seeds with greater productivity and production requirements at a lower cost.

Landscape connectivity affects individual survival in unstable patch networks: The case of a freshwater turtle inhabiting temporary ponds

AbstractThe loss of connectivity is among the main threats for species occupying freshwater pond networks. Landscape connectivity can impact the persistence of patchy populations by reducing movement rates among ponds, thereby increasing the likelihood of local extinctions in source–sink systems, and reducing the probability of colonisation following extinctions. In addition, loss of connectivity may also reduce survival rates if individuals have to cross a hostile matrix, though this hypothesis has been rarely tested. Here, we address these issues by evaluating how individual survival and inter‐patch movement probabilities of the European pond turtle (Emys orbicularis) are influenced by patch connectivity.The study was carried out in a network of temporary ponds embedded in a heterogeneous agricultural matrix in southwestern Portugal, encompassing a period associated with a severe drought (2003–2005) and another with wetter climatic conditions (2010–2014). We mapped the location of ponds and land uses around each pond, and quantified connectivity among ponds using least‐cost distances based on patch location and resistance to movement of different land uses. We then used multistate capture‐recapture modelling to quantify how survival and movement of this freshwater turtle were related to different metrics of landscape connectivity, in the wet and dry periods.We captured 221 pond turtles, including 89 juveniles, 58 females, and 74 males. Survival was higher in ponds more connected with other ponds, especially for juvenile turtles. The probability of movement between ponds decreased with increasing least‐cost distances. Movement probabilities tended to be higher in the dry than in the wet period.Our results support the idea that landscape connectivity affects both movement and survival rates in a patchy population inhabiting a temporary pond network. These effects are likely to be particularly marked in unstable freshwater systems like ours, where individuals may have to move widely to escape drying ponds during particularly dry years.Overall, our findings suggest that focusing conservation efforts solely on protecting discrete freshwater habitats such as temporary ponds may be insufficient, requiring also due consideration of landscape connectivity offered by the surrounding agricultural matrix to assure long‐term persistence of patchy populations inhabiting such habitats.

The frailty of tropical restoration plantings

Conserving and restoring biodiversity are compelling challenges in the face of deforestation and fragmentation of tropical forests. Establishing restoration plantings that act as stepping‐stone corridors for animals and develop into forest islets is one way we can reconnect forest fragments split by active agricultural landscapes. However, this strategy's success is contingent on dispersal agents attracted from the forests that vary greatly in their dispersal services, diet, and mobility. Dispersal agents capable of traversing the agricultural matrix that also provide high‐quality and high‐quantity seed dispersal are often a small subset of the present fauna. They also tend to be large‐bodied birds with broad diets (e.g. toucans). This subset of dispersal agents (here termed “effective restoration agents”) plays a key role in driving succession in restoration plantings. Their absence or low numbers can compromise the strategy of using plantings to enhance connectivity in landscapes fragmented by crops, orchards, or extensive pastures. In this event, additional intervention may be required to attract other dispersal agents that would otherwise not disperse seeds at or play a significant role in restoration plantings.

Sympatric Bat Species Prey Opportunistically on a Major Moth Pest of Pecans

Native predators provide undervalued pest suppression services to agriculture. Studies of pest consumption by insectivorous bats tend to focus upon single species in large, centralized colonies, while bats dispersed in small groups within the agricultural matrix often go unnoticed. Pecan trees, Carya illinoinensis, and the destructive pecan nut casebearer (PNC) moth, Acrobasis nuxvorella, comprise a tightly linked host–parasite system in a widespread agroecosystem native to North America. Here we use a quantitative polymerase chain reaction (qPCR) assay of fecal DNA to document predation on PNC moths by an assemblage of sympatric bat species across episodic peaks in PNC abundance. Although five species of bats consume PNC moths, greater predation by a solitary tree-roosting bat (eastern red bat, Lasiurus borealis) than other species is suggested by a higher frequency of PNC occurrence and quantity of PNC gene copies in fecal samples. Consumption of PNC by bats during all documented peaks in moth activity suggests that predation pressure occurs throughout the PNC season. Our results highlight the need to consider multi-species assemblages and different foraging strategies when assessing pest suppression services, particularly in agroforestry or tree crops. Assessing the diet of only common or easily captured species limits our ability to accurately document pest consumption by bats.

Integrating habitat- and species-based perspectives for wetland conservation in lowland agricultural landscapes

Wetlands are among the most endangered ecosystems worldwide with multiple direct and indirect stressors, especially in human-altered areas like intensive agricultural landscapes. Conservation management and efforts often focus on species diversity and charismatic taxa, but scarcely consider habitats. By focusing on a complex formed by 107 permanent wetlands at 18 Natura 2000 sites in the Emilia-Romagna region (northern Italy), the patterns of habitats of conservation concern were investigated and the concordance with threatened species patterns was analysed. Wetlands were characterised in terms of morphology, connectivity, land use and management as drivers of assemblage and richness patterns of habitats. Our results showed a strong concordance between the distribution and richness patterns of both habitats and threatened taxa (birds, mammals, amphibians, reptiles, fish, invertebrates, and plants). Thus, habitats seem an effective proxy of species patterns. The variables related with perimeter, environmental heterogeneity and presence of water bodies were the most important ones associated with habitat richness patterns. The presence of aquatic systems (measured as the percentage of wetland area occupied by an aquatic surface) and their position in the hydrographic network were associated mostly with habitats distribution. Low richness wetlands (in habitat terms) were not complementary as no new habitat types were supported. The results stressed the relevance of wetlands with wide water body perimeters composed of diverse systems as being key for biodiversity conservation in a simplified agricultural matrix. Integrating habitat- and species-based perspectives seems a promising field and may provide a rapid assessment tool to acquire effective information for wetlands conservation and assessment.

An analytical study of agricultural price policies for the best important sugar crops in Egypt

The development of the agricultural sector is influenced by a range of economic policies, the most important of them is the agricultural price policies, whose objectives vary with different stages of economic development as well as the economic policies followed in the country. Sugar cane and sugar beet crops are sugar crops that are used not only in Egypt but in most countries of the world. The problem of the study was the inability of the local sugar production of 2196 thousand tons to cope with the increase in the requirements of increasing domestic consumption of about 3230 thousand tons in the light of the inability to expand the cultivation of sugar cane as a main crop in sugar production in Egypt, and the growing food gap. Sugar imports, which amounted to about 964 thousand tons, and then increase the import gap, which reflects negatively on the agricultural trade balance, which entails knowing the changes in the Egyptian agricultural policies and the changes that resulted in distortions in the markets. Therefore, the study aimed to estimate some economic transactions to identify the essence of the Egyptian agricultural policies followed by the state in the production of the crop to know the extent of deviation of market prices for sugar crops from economical prices to see the degree of non-employment of resources. The following conclusions were reached: The results of the analysis of the agricultural policy matrix of the crops under study showed that the nominal protection coefficient of production inputs was estimated at 0.74 and 0.69 for sugarcane and sugar beet crops, respectively, indicating that there is no support for production inputs. The nominal protection coefficient of production was estimated at 0.74 and 0.76 for sugarcane and sugar beet crops, respectively, indicating that the state imposes direct and indirect taxes on the product and provides subsidies to the consumer. The effective protection coefficient, estimated at 0.74 and 0.77, for sugarcane and sugar beet crops, respectively, indicates implicit taxes, which means that the value-added of these crops is low and therefore not protected during the study period. The comparative advantage coefficient was about 27% and 31%, indicating a comparative advantage for Egypt in the production of sugarcane and sugar beet crop during the study period respectively, where 0.27 and 0.31 local resources are needed to generate unit of foreign currency for sugar cane and sugar beet crops during Period of study, respectively.

Human-modified landscapes alter mammal resource and habitat use and trophic structure

The broad negative consequences of habitat degradation on biodiversity have been studied, but the complex effects of natural-agricultural landscape matrices remain poorly understood. Here we used stable carbon and nitrogen isotopes to detect changes in mammal resource and habitat use and trophic structure between preserved areas and human-modified landscapes (HMLs) in a biodiversity hot spot in South America. We classified mammals into trophic guilds and compared resource use (in terms of C3- and C4-derived carbon), isotopic niches, and trophic structure across the 2 systems. In HMLs, approximately one-third of individuals fed exclusively on items from the agricultural matrix (C4), while in preserved areas, ∼68% depended on forest remnant resources (C3). Herbivores, omnivores, and carnivores were the guilds that most incorporated C4 carbon in HMLs. Frugivores maintained the same resource use between systems (C3 resources), while insectivores showed no significant difference. All guilds in HMLs except insectivores presented larger isotopic niches than those in preserved areas. We observed a complex trophic structure in preserved areas, with increasing δ15N values from herbivores to insectivores and carnivores, differing from that in HMLs. This difference is partially explained by species loss and turnover and mainly by the behavioral plasticity of resilient species that use nitrogen-enriched food items. We concluded that the landscape cannot be seen as a habitat/nonhabitat dichotomy because the agricultural landscape matrix in HMLs provides mammal habitat and opportunities for food acquisition. Thus, favorable management of the agricultural matrix and slowing the conversion of forests to agriculture are important for conservation in this region.

Hantavirus host assemblages and human disease in the Atlantic Forest.

Several viruses from the genus Orthohantavirus are known to cause lethal disease in humans. Sigmodontinae rodents are the main hosts responsible for hantavirus transmission in the tropical forests, savannas, and wetlands of South America. These rodents can shed different hantaviruses, such as the lethal and emerging Araraquara orthohantavirus. Factors that drive variation in host populations may influence hantavirus transmission dynamics within and between populations. Landscape structure, and particularly areas with a predominance of agricultural land and forest remnants, is expected to influence the proportion of hantavirus rodent hosts in the Atlantic Forest rodent community. Here, we tested this using 283 Atlantic Forest rodent capture records and geographically weighted models that allow us to test if predictors vary spatially. We also assessed the correspondence between proportions of hantavirus hosts in rodent communities and a human vulnerability to hantavirus infection index across the entire Atlantic Forest biome. We found that hantavirus host proportions were more positively influenced by landscape diversity than by a particular habitat or agricultural matrix type. Local small mammal diversity also positively influenced known pathogenic hantavirus host proportions, indicating that a plasticity to habitat quality may be more important for these hosts than competition with native forest dwelling species. We found a consistent positive effect of sugarcane and tree plantation on the proportion of rodent hosts, whereas defaunation intensity did not correlate with the proportion of hosts of potentially pathogenic hantavirus genotypes in the community, indicating that non-defaunated areas can also be hotspots for hantavirus disease outbreaks. The spatial match between host hotspots and human disease vulnerability was 17%, while coldspots matched 20%. Overall, we discovered strong spatial and land use change influences on hantavirus hosts at the landscape level across the Atlantic Forest. Our findings suggest disease surveillance must be reinforced in the southern and southeastern regions of the biome where the highest predicted hantavirus host proportion and levels of vulnerability spatially match. Importantly, our analyses suggest there may be more complex rodent community dynamics and interactions with human disease than currently hypothesized.

Herbivore corridors sustain genetic footprint in plant populations: a case for Spanish drove roads.

Habitat fragmentation is one of the greatest threats to biodiversity conservation and ecosystem productivity mediated by direct human impact. Its consequences include genetic depauperation, comprising phenomena such as inbreeding depression or reduction in genetic diversity. While the capacity of wild and domestic herbivores to sustain long-distance seed dispersal has been proven, the impact of herbivore corridors in plant population genetics remains to be observed. We conducted this study in the Conquense Drove Road in Spain, where sustained use by livestock over centuries has involved transhumant herds passing twice a year en route to winter and summer pastures. We compared genetic diversity and inbreeding coefficients of Plantago lagopus populations along the drove road with populations in the surrounding agricultural matrix, at varying distances from human settlements. We observed significant differences in coefficients of inbreeding between the drove road and the agricultural matrix, as well as significant trends indicative of higher genetic diversity and population nestedness around human settlements. Trends for higher genetic diversity along drove roads may be present, although they were only marginally significant due to the available sample size. Our results illustrate a functional landscape with human settlements as dispersal hotspots, while the findings along the drove road confirm its role as a pollinator reservoir observed in other studies. Drove roads may possibly also function as linear structures that facilitate long-distance dispersal across the agricultural matrix, while local P. lagopus populations depend rather on short-distance seed dispersal. These results highlight the role of herbivore corridors for conserving the migration capacity of plants, and contribute towards understanding the role of seed dispersal and the spread of invasive species related to human activities.

Landscape heterogeneity effects on keystone rodent species: agro-ecological zoning for conservation of open grasslands

Grasslands are one of the most threatened ecosystems in the world. Spatial prioritization of high quality habitat in agricultural landscapes is needed to protect grassland biodiversity. Within this context, we focused on European ground squirrel, a keystone species in steppe and salt steppe ecosystems. Using historical data and habitat field mapping, this study evaluates species distribution and site occupancy along the southern margin of the species range (Serbia) and identifies priority conservation zones in an intensively used landscape. Using gap analysis to evaluate changes in distribution over time and land protection status of the occupied area, we found that the regional species range has been constricted by 70%, and that 43% of mapped areas were outside of conservation networks. We also used a landscape structure model and multivariate analysis to identify the effects of spatial heterogeneity on occupancy. After mapping potential conservation zones with a buffer radius of 4.6 km—the scale with significant effects on occupancy—we identified 19 potential agro-ecological zones that cover the full range of mapped species habitats. The proposed agro-ecological zones differ in percentage of occupancy, which was found to increase with the overall landscape heterogeneity. This study contributes to the ongoing effort to broaden the understanding of the ecology and conservation of the European ground squirrel and the grasslands they rely on. Conservation planning should be designed to protect grasslands occupied by ground squirrels, ensure that the agricultural matrix is permeable, and to sustain or enhance landscape heterogeneity.

Space Use and Habitat Selection of American Badgers (Taxidea Taxus) in Southwestern Wisconsin

Badger (Taxidea taxus) life history and ecology are poorly described despite widespread distribution in North America. We used radio-telemetry to estimate home range size and quantify habitat selection for badgers living in agricultural habitat in southwestern Wisconsin, U.S.A. Badgers in Wisconsin established relatively large home ranges (3 to 30km2), with those of males tending to be larger than females. Badgers selected broadly for nonforested grassland habitat in a matrix of agriculture, although fine-scale use varied substantially by individual. These patterns suggest that badgers tolerate levels of human alteration associated with agriculture in Wisconsin, although there may be limits to that tolerance.

On Bird Species Diversity and Remote Sensing—Utilizing Lidar and Hyperspectral Data to Assess the Role of Vegetation Structure and Foliage Characteristics as Drivers of Avian Diversity

Avian diversity has long been used as a surrogate for overall diversity. In forest ecosystems, it has been assumed that vegetation structure, composition, and condition have a significant impact on avian diversity. Today, these features can be evaluated via remote sensing. This study examined how structure metrics from lidar data and narrowband indices from hyperspectral data relate with avian diversity. This was assessed in four deciduous-dominated woods with differing age and structure set in an agricultural matrix in eastern England. The woods were delineated into cells within which metrics of avian diversity and remote sensing based predictors were calculated. Best subset regression was used to obtain best lidar models, hyperspectral models, and finally, the best models combining variables from both data sets. The aims were not only to examine the drivers of avian diversity, but to assess the capabilities of the two remote sensing techniques for the task. The amount of understorey vegetation was the best single predictor, followed by foliage height diversity, reflectance at 830 nm, anthocyanin reflectance index 1, and Vogelmann red edge index 2. This showed the significance of the full vertical profile of vegetation, the condition of the upper canopy, and potentially tree species composition. The results thus agree with the role that vegetation structure, condition, and floristics are assumed to have for diversity. However, the inclusion of hyperspectral data resulted in such minor improvements to models that its collection for these purposes should be assessed critically.

Multiscale effects of wetland availability and matrix composition on wetland breeding birds in Minnesota, USA

Abstract The increasing intensity of wetland stressors in the Upper Midwestern United States hastens the need to understand how matrix composition influences wetland bird occurrence and abundance. The optimal spatial scale for assessing species–habitat relationships is not always apparent, but may affect inference about wetland use and suitability. We developed occupancy and abundance models, accounting for imperfect detection, for 9 wetland bird species breeding in Minnesota. We evaluated land cover associations at 3 spatial scales (12.6 ha, 50.3 ha, and 4,000 ha), quantified species-specific sensitivity to wetland availability and matrix habitat composition (agricultural and developed land covers), and assessed ecoregional variation in occupancy and abundance. Amount of wetland cover was positively associated with occupancy of 89% of species and with abundance of 67% of species, but the spatial scale of support differed among species. American Bittern (Botaurus lentiginosus), Pied-billed Grebe (Podilymbus podiceps), and Wilson’s Snipe (Gallinago delicata) in particular were negatively impacted by anthropogenic land uses within the surrounding matrix, indicating a need to shift wetland conservation planning from the site scale to the landscape scale to capture pertinent drivers of wetland bird habitat use. Mean expected occupancy across all species was greatest in the Prairie Pothole Region (PPR), suggesting that restoration efforts within this ecoregion are likely to maintain wetland bird diversity. However, given the minimal total wetland availability and predominantly agricultural matrix in the PPR, protecting wetlands and upland buffers in the Aspen Parklands or Boreal ecoregions may represent a better investment for agricultural-sensitive species such as American Bittern, Sandhill Crane (Antigone canadensis), and Wilson’s Snipe. Our modeling approach provides a multi-species framework for identifying habitat management priorities; future applications at broader spatial extents can continue to improve wetland bird conservation in a region with high rates of wetland loss and degradation.

Secondary Shrubby Communities Provide Nesting Habitat for Birds in a Semiarid Agricultural Landscape

Loss and fragmentation of natural and semi-natural vegetation caused by agricultural intensification are related to many declines in shrubland bird populations, but they have received little conservation attention and research effort. In the Llanos de Ojuelos, a semiarid agricultural landscape in Mexico, patches of natural shrubland and nopal (or prickly pear) Opuntia spp. orchards harbour 60% of the regional avifauna, but prior to this study their value as nesting habitat for birds has not been assessed. In 2014 we recorded 143 nests of 25 species, 45% of which were of Mourning Doves Zenaida macroura. The nesting birds recorded account for 38% of all species known to use these habitats in this region and the number of nesting species is larger than in other North American semiarid and arid shrublands. Shrublands and orchards were not different in any habitat attributes measured, nor in the densities of nests found in them, but there were significantly more species nesting in shrublands. Nest height and visibility were not different between habitats, except for Mourning Doves, which nested at a lower height in orchards. Neither attribute affected nest success, except for in Black-chinned Sparrow Spizella atrogularis for whom successful nests were less visible. The assemblages of nesting birds might be explained better by particular plants used as nest substrate than by habitat attributes. Catclaws Mimosa aculeaticarpa var. biuncifera, Huisaches Vachellia farnesiana and V. schaffneri and nopal plants supported 56% of all nests, the latter being particularly important for Mourning Doves, while scarce Central-Mexico Yucca Yucca decipiens trees supported 40% of nesting species. There were interspecific differences in the phenology of nesting, which matched the feeding requirements of the young. Nopal orchards seem to provide abundant complementary food for birds that nest in shrubland patches. Nopal orchards and shrubland patches dotting the landscape may make the dominant agricultural matrix of the southern part of the Central Plateau of Mexico less detrimental to shrubland birds. Our study supports the idea that small patches of secondary shrubland can aid in biodiversity conservation in anthropized landscapes, a role that in this region is provided by shrubland remnant patches as well as nopal orchards.

Drivers of plant functional group richness and beta diversity in fire‐dependent pine savannas

AbstractAimTo assess the drivers of plant functional group richness and beta diversity in fire‐maintained North American Coastal Plain (NACP) savannas.LocationThe southern portion of the NACP, a global biodiversity hotspot. This region is characterized by fire‐dependent pine savanna fragments that are isolated within a matrix of agriculture, urban development, non‐pyrogenic plant communities and plantation forestry.MethodsWe used nested quadrats to sample plant species on 30 fire‐maintained savanna preserves in Florida and Georgia, USA. We analysed between‐site Sørenson dissimilarity, a measure of beta diversity, using NMDS and PerMANOVA. We measured nestedness using NODF, and we used Betapart to partition Sørenson dissimilarity into nestedness and turnover components. We used linear and generalized linear mixed models to explore drivers of functional group richness and composition, including fire regime (return interval, number of fires, time since fire and seasonality), vegetation structure (herbaceous cover, woody cover and tree density) and spatial factors (surrounding landscape and geographic distance).ResultsWe found turnover‐dominated beta‐diversity patterns in all functional groups. Turnover was explained partly by spatial and environmental gradients, but roughly half of the turnover between sites was unexplained. Species richness was higher on sites where fire and fire surrogates had been used longer and more consistently, and these effects were partly independent of current vegetation structure. Fire regimes containing more growing season fire and more diversity of burn seasons promoted higher species richness. Relationships between small‐scale and large‐scale species richness varied by soil type and functional group.Main conclusionsFire‐maintained savannas in the southeastern NACP vary greatly in their plant functional group richness, but high beta diversity resulting primarily from species turnover suggests that even species‐poor sites can harbour less‐common members of the regional plant metacommunity. Prescribed fire regimes that include growing season fire as well as a diversity of burn seasons may best promote species and functional group richness.

Land-sparing agriculture sustains higher levels of avian functional diversity than land sharing.

The ecological impacts of meeting rising demands for food production can potentially be mitigated by two competing land-use strategies: off-setting natural habitats through intensification of existing farmland (land sparing), or elevating biodiversity within the agricultural matrix via the integration of "wildlife-friendly" habitat features (land sharing). However, a key unanswered question is whether sparing or sharing farming would best conserve functional diversity, which can promote ecosystem stability and resilience to future land-use change. Focusing on bird communities in tropical cloud forests of the Colombian Andes, we test the performance of each strategy in conserving functional diversity. We show that multiple components of avian functional diversity in farmland are positively related to the proximity and extent of natural forest. Using landscape and community simulations, we also show that land-sparing agriculture conserves greater functional diversity and predicts higher abundance of species supplying key ecological functions than land sharing, with sharing becoming progressively inferior with increasing isolation from remnant forest. These results suggest low-intensity agriculture is likely to conserve little functional diversity unless large blocks of adjacent natural habitat are protected, consistent with land sparing. To ensure the retention of functionally diverse ecosystems, we urgently need to implement mechanisms for increasing farmland productivity whilst protecting spared land.

Ant community patterns in highly fragmented Chaco forests of central Argentina

AbstractThe Chaco is the largest dry forest biome in South America and one of the regions most threatened by agricultural intensification. As a consequence, in several areas Chaco forests persist as forest remnants of different sizes embedded in an agricultural matrix. Ants are social insects that have key roles in ecosystem functioning, and the effects of this ongoing land use change process on ant communities are little known for this region. In the present study, we assessed the consequences of land use replacement by monocultures and forest fragmentation on ant communities. Particularly, we assessed whether patch size, patch isolation and edge effect affect species richness and composition of ground‐dwelling ants in fragmented landscapes of Chaco forests. We collected ants by combining hand collecting and pitfall traps in 17 forest fragments and the surrounding matrix from two sites in Córdoba, Argentina. Patch size and patch isolation had no effect on ant richness; however, patch isolation and, to a lesser extent, patch size altered ant species composition. The ant community was not affected by edge but it was negatively affected by the crop matrix, which reduced richness and altered species composition. These results indicate that monoculture matrices severely affect ant communities in the Chaco forests, and that the effects of other indicators of habitat fragmentation (patch size and edge effect) are subtler and less relevant. In the present context of land use change, even small fragments could have an important value for the conservation of ant diversity.

Forest edge effects on the mycorrhizal communities of the dual-mycorrhizal tree species Alnus glutinosa (L.) Gaertn.

Forest conversion into agricultural land has resulted in a continuous decline in forest cover and in a reduced size and increased edge-to-core ratio of the remaining fragments. Forest edges are more directly exposed to sunlight, wind and pollutants and the resulting changes in habitat quality might have a large impact on plant and animal communities. Few studies, however, have focused on forest edge effects on mycorrhizal fungus communities. Here, we used high-throughput sequencing to study how communities of arbuscular mycorrhizal (AMF) and ectomycorrhizal fungi (EcMF), present in both the roots of the dual mycorrhizal tree Alnus glutinosa and in the soil, changed with increasing distance from the forest edge within fragmented forests embedded in an intensively managed agricultural matrix. Overall, we found 158 AMF OTUs and 275 EcMF OTUs. Soil moisture content increased with increasing distance from the forest edge, whereas soil nitrate concentration increased with increasing distance in south-facing and decreased in north-facing edges. Distance to the forest edge had a significant effect on EcMF community composition that largely overlapped with the observed changes in soil variables, especially soil moisture content. Apart from this distance effect, there were also clear effects of edge orientation on mycorrhizal diversity and community composition. While AMF OTU richness was higher at south- than at north-facing edges, the opposite pattern was found for EcMF. Community composition of both mycorrhiza types also differed significantly between south- and north-facing edges. We conclude that altered environmental conditions at forest edges cause significant changes in mycorrhizal communities, which could subsequently affect ecosystem functioning.

Agricultural intensification drives butterfly decline

Abstract Severe losses of insects have taken place over major parts of Europe. This negative trend is assumed to be largely the result of agricultural intensification. To analyse potential factors causing this loss of species, we assessed butterfly communities at 21 grassland patches. Seventeen of these were distributed across an agricultural landscape dominated by crop fields; four were embedded in two adjoining managed semi‐natural grassland areas. We assessed environmental parameters such as patch size and habitat quality for each grassland patch. We further incorporated the surrounding land‐cover considering different degrees of land‐use intensity. We classified butterfly species into generalists and specialists according their ecological and behavioural characteristics. As in the managed semi‐natural reference grasslands, species richness and abundance were higher in patches surrounded by extensively used grasslands and unsprayed crop fields, and lower in patches surrounded by sprayed crop fields. Furthermore, blossom density positively affected butterfly occurrence. Our data revealed that specialised butterfly species mainly occur in managed semi‐natural grassland sites, and are largely absent from other grassland plots embedded in the agricultural matrix. Our study underlines the negative impacts of intense conventional agriculture on butterfly species richness and abundance and reveals the urgent need for more nature‐friendly cultivation methods. In situ experiments may help to understand and disentangle single drivers causing this negative trend.