Plant Phenology

In Portugal, the wine-grape sector has a crucial economic, social and cultural relevance, especially in many inland regions of the country namely the Alto Douro Wine Region. It is the oldest legislated viticultural region in the world (since 1756) and has a typical Mediterranean climate with hot and dry summers. Recent-past temperature trends, focusing on European viticultural regions, show that the growing season mean temperatures have increased nearly 2ºC from 1950 to 2004. Future projections point to temperature increases and precipitation changes in the growing season, which may bring changes in grapevine physiology and consequently in yield and wine quality. Although grapevines have several survival strategies, the amounting evidence for significant climate change in the upcoming decades urges adaptation measures to be taken. Short term adaptation measures should be considered as the first protection strategy against climate change and should focus on specific threats. Among th...

Plant phenology is strongly controlled by climate and has consequently become one of the most reliable bioindicators of ongoing climate change. We used a dataset of more than 200 000 records for six phenological events of 29 perennial plant species monitored from 1943 to 2003 for a comprehensive assessment of plant phenological responses to climate change in the Mediterranean region. Temperature, precipitation and North Atlantic Oscillation (NAO) were studied together during a complete annual cycle before phenological events to determine their relative importance and potential seasonal carry‐over effects. Warm and dry springs under a positive phase of NAO advance flowering, leaf unfolding and fruiting dates and lengthen the growing season. Spatial variability of dates (range among sites) was also reduced during warm and dry years, especially for spring events. Climate during previous weeks to phenophases occurrence had the greatest impact on plants, although all events were also affected by climate conditions several months before. Immediate along with delayed climate effects suggest dual triggers in plant phenology. Climatic models accounted for more than 80% of variability in flowering and leaf unfolding dates, and in length of the growing season, but for lower proportions in fruiting and leaf falling. Most part of year‐to‐year changes in dates was accounted for temperature, while precipitation and NAO accounted for <10% of dates' variability. In the case of flowering, insect‐pollinated species were better modelled by climate than wind‐pollinated species. Differences in temporal responses of plant phenology to recent climate change are due to differences in the sensitivity to climate among events and species. Spring events are changing more than autumn events as they are more sensitive to climate and are also undergoing the greatest alterations of climate relative to other seasons. In conclusion, climate change has shifted plant phenology in the Mediterranean region.

Avian fruit consumption may ensure plant reproductive success when frugivores show consistent preference patterns and effectively remove and disperse seeds. In this study we examined avian fruit preferences and their seed-removal services at five study sites in north-central Puerto Rico. At each site, we documented the diet of seven common fruit-eating avian species from February to September 1998. Using foraging observations and area-based estimates of fruit abundance, we examined preference patterns of birds. We found that 7 out of 68 fleshy-fruited plant species were responsible for most of the fruit diet of birds. Seventeen plant species were preferred and four of them were repeatedly preferred across several study sites and times by at least one avian species. Preferred plant species comprised a small percentage of fleshy fruits at each site (<15% in four out of five study sites), but showed extended phenology patterns. The quantity of seeds removed by frugivore species was not strictly related to preferences. Some frugivores showing no preference could effectively remove more seeds from plants at some locations than species exhibiting constancy in their patterns of preference. Only two frugivores, Euphonia musica and Vireo altiloquous, removed most of the seeds of plants for which they exhibited repeated preference across the landscape. Preference patterns, particularly those exhibiting consistency in space and time for plant species having prolonged fruiting periods, may have important mechanistic consequences for the persistence, succession, and regeneration of tropical plant communities.

Fenologi tumbuhan menggambarkan fasa kitaran hidup atau aktiviti tumbuhan dan adalah penting untuk memahami interaksinya dengan iklim. Kajian dilakukan untuk mengenal pasti respons fenologi tumbuhan dan metrik fenologi hutan dipterokarpa, kelapa sawit dan pokok getah menggunakan data indeks tumbuhan Enhanced Vegetation Index (EVI) daripada MODIS-Aqua (produk MYD13Q1) dan purata hujan bulanan sepanjang tahun 2007 dan 2009 di negeri Johor. Pola hujan pada tahun 2007 menunjukkan taburan hujan normal, manakala tahun 2009 mengalami kekurangan hujan sepanjang tempoh sebelas tahun (2000-2010). Hasil mendapati tren EVI hutan dipterokarpa lebih bervariasi pada 2009 dengan nilai EVI antara 0.39-0.64 berbanding tren pada 2007 yang tekal dengan nilai EVI antara 0.33-0.57. Tren fenologi kelapa sawit pada 2007 lebih kerap mengalami turun naik berbanding pada 2009, masing-masing dengan EVI antara 0.45-0.71 dan 0.5-0.74. Corak fenologi pokok getah pada kedua-dua tahun kajian adalah sama dan julat EVI pada 2009 adalah lebih kecil berbanding 2007, masing-masing dengan EVI antara 0.39-0.62 dan 0.30-0.73. Pengaruh masa susulan ke atas tahap kehijauan tumbuhan telah dikesan, khususnya selepas peristiwa hujan lebat dalam dua tahun tersebut dan sedikit sebanyak mempengaruhi nilai korelasi antara pemboleh ubah purata hujan bulanan dengan EVI tumbuh-tumbuhan. Permulaan dan pengakhiran musim pertumbuhan hutan dipterokarpa bagi kedua-dua tahun berlaku dalam bulan yang sama, iaitu Februari (permulaan musim) dan Disember (pengakhiran musim). Tidak wujud perbezaan yang ketara antara panjang musim pertumbuhan kelapa sawit bagi kedua-dua tahun, iaitu hanya 32 hari lebih panjang pada 2007 berbanding 2009. Musim pertumbuhan pokok getah pula adalah lebih panjang pada 2007 dan lebih singkat pada 2009, masing-masing 176 hari dan 113 hari. Kata kunci: EVI; fenologi tumbuhan; metrik fenologi; MODIS; musim pertumbuhan

ABSTRACT Vegetation phenology describes the plant life cycle or activity and it is important to understand it's interactions with climate. This study was conducted to identify plant phenological responses to average monthly rainfall and to extract the phenology metrics for dipterocarp forest, oil palms and rubber trees by using EVI vegetation indices from MODIS-Aqua (product MYD13Q1) and an average of monthly rainfall for 2007 and 2009. Rainfall patterns in 2007 showed normal rainfall distribution whilst in 2009 experienced less rain in a period of eleven years (2000-2010). The result showed that the EVI of the dipterocarp forest is varied in 2009 with EVI value ranges 0.39-0.64 compared to the more consistent EVI values of 0.33-0.57 in 2007. The phenological trends of oil palms fluctuate in 2007 compared to 2009 with EVI at 0.45-0.71 and 0.5-0.74, respectively. Phenological patterns of rubber trees in both years showed similar trend and the EVI range of 2009 was smaller than in 2007 with value of 0.39-0.62 and 0.30-0.73, respectively. The effect of lag period on vegetations' greenness was detected, especially after heavy rain period in both years which affects the correlation values between the average rainfall and EVI. The start and end of growing season of the dipterocarp forest for both years occurred in February and December. There is no clear difference between the lengths of season for oil palms in both years, which is 32 days longer in 2007 compared to 2009. Length of season for rubber tree is longer in 2007 and significantly shorter in 2009 at 176 and 113 days, respectively.

It is well documented that plant and animal
phenology is changing in response to recent climate
warming in the Palaearctic. However, few long-term
data sets are currently available in the Mediterranean
basin. The present study reports long-term temporal
trends of several phenophases of 45 plants, 4 insects
and 6 migratory insectivorous birds. Dynamic factor
analyses performed with plant phenophases showed
that most of those events occurring at spring and
summer had common trends toward the advancement,
especially since mid-1970s. However, during these last
decades, insect phenology showed a steeper advance
than plant phenology, suggesting an increase of decoupling
of some plant–insect interactions, such as
those between pollinators and flowers or herbivorous
insects and their plant resources. All trans-Saharan bird
species showed highly significant temporal trends in all
studied phenophases (some of them covering most of
the last century). In two species, the duration of stay is
increasing due to both earlier arrivals and later
departures. On the other hand, two wintering species
showed a significant advancement in their arrival dates,
while an opposite pattern were found for departures of
each one. Only one of these species increased significantly
its wintering stay. Bird departures were not
related to local climate in any species. Our results
demonstrate a key role of local temperatures behind
interannual variability of most plant and insects
phenophases, with especial emphasis in those occurring
in spring and summer. Therefore, the common signal
towards the advancement recorded since mid-1970s
resulted from the recent rise in temperatures.

Keywords Dynamic factor analysis , Insects ,
Migratory birds , Plants , Plant–insect interactions

SUMMARY
Thirty strains of bacteria were evaluated for their
effect on germination and growth of lettuce (Lactuca
sativa L. var. Longifolia). For germination, highly
significant differences were found among the effects of
the treatments. The strain Hafnia alvei P-3 increased
germination more than 36.5% relative to the control. In
contrast, the Pseudomonas aeruginosa strains 7PS and
11PS inhibited germination. The growth of the plant
was promoted by all of the inoculating strains except
H. alvei P-25, which had the same effect as the control. The largest effect on growth was obtained
with the RIB strain (unidentified), which increased
fresh weight by 277%, dry weight by 371%, leaf area
by 240% and root volume by 300%. The results
suggest that the growth-promoting bacteria are
potentially useful in the production of vegetable
seedlings.

Index words: Rhizosphere, rhizobacteria, isolation,
propagation.

Different interactions occur simultaneously, affecting the ecological and evolutionary outcome of the species within a community. Mutualisms are particularly relevant for maintaining and generating biodiversity, and among them, pollination and seed dispersal play a central role in plant regeneration. Due to its parasitic life-form and ecological specialization, mistletoes provide a good study system to assess the effects of simultaneous interactions in the wild. We used the highly specialized mistletoe Tristerix aphyllus, its pollinator (the hummingbird Sephanoides sephaniodes), and its seed disperser (the mockingbird Mimus thenca) to assess their daily activity patterns during a flowering-fruiting overlap period. Given that both bird species are diurnal, we expect them to have different visitation times despite using different resources. Using camera traps, we found that both species have different daily activity patterns (overlap index Δ 4 = 0.83, p < 0.001). While M. thenca had a narrow activity period early in the morning, S. sephaniodes had a wider activity range. We also found that the temporal variation of those activity patterns might be related to resource availability, as the number of flowers has decreased (F 2,52 = 13.85, p < 0.001) over time, while the number of ripe fruits has increased (F 2,52 = 5.16, p = 0.009) over time. Our results show that having different activity patterns could be a coexistence mechanism among bird species interacting with the same plant but exploiting different resources. Thus, taking activity patterns into account can provide a better understanding of ecological processes involving multiple interactions taking place simultaneously in the community.

The study of vegetation phenology has great relevance in many fields since the importance of knowing timing and shifts in periodic plant life cycle events to face the consequences of global changes in issues such as crop production, forest management, ecosystem disturbances, and human health. The availability of high spatial resolution and dense revisit time satellite observations, such as Sentinel-2 satellites, allows high resolution phenological metrics to be estimated, able to provide key information from time series and to discriminate vegetation typologies. This paper presents an automated and transferable procedure that combines validated methodologies based on local curve fitting and local derivatives to exploit full satellite Earth observation time series to produce information about plant phenology. Multivariate statistical analysis is performed for the purpose of demonstrating the capacity of the generated smoothed vegetation curve, temporal statistics, and phenological metrics to serve as temporal discriminants to detect forest ecosystems processes responses to environmental gradients. The results show smoothed vegetation curve and temporal statistics able to highlight seasonal gradient and leaf type characteristics to discriminate forest types, with additional information about forest and leaf productivity provided by temporal statistics analysis. Furthermore, temporal, altitudinal, and latitudinal gradients are obtained from phenological metrics analysis, which also allows to associate temporal gradient with specific phenophases that support forest types distinction. This study highlights the importance of integrated data and methodologies to support the processes of vegetation recognition and monitoring activities.

La percepción remota desde sensores (multiespectrales e hiperespectrales) instalados a bordo de satélites espaciales aporta una visión global de la superficie terrestre. Esta visión es sistemática cuándo los programas de teledetección están diseñados para la observación periódica en el tiempo y en el espacio, hecho que permite estudiar los ciclos de la vegetación: la fenología. En este trabajo, analizamos una serie temporal basada en 15 años de imágenes del sensor MODIS en la que utilizamos como unidad mínima de observación el NDVI promedio mensual de los datos de reflectividad del citado sensor a una resolución espacial de 250 metros. De este modo, después de un riguroso pre-procesamiento de los datos, generamos una serie temporal con frecuencia mensual - una por cada mes-  integrada por 180 imágenes, desde enero de 2002 hasta diciembre de 2016, y abordamos un análisis fenológico estacional aplicado a la superficie forestal con masas densas de alcornoque en el sur de la península Ibérica. Los resultados revelaron una primera aproximación a la caracterización de la fenología de estas masas forestales. A escala regional, la especie mostró un NDVI promedio de 0,68, alcanzando una cifra 0,76 en las poblaciones del suroeste de Andalucía donde los píxeles sólo informaron sobre copas. Considerando el conjunto de la región, los valores máximos se dieron en noviembre (0,74) y los valores mínimos en septiembre (0,62),  mientras que en las poblaciones del suroeste donde se produce el óptimo de la especie y aparecen masas más densas, los extremos en el NDVI oscilaron entre 0,81 y 0,76.