In the Central Desert of northern Baja California, blue fan palm populations (Brahea armata) are found as isolated oases on mountaintops and along canyons with ephemeral flow conditions. Here, the effect of the intera...In the Central Desert of northern Baja California, blue fan palm populations (Brahea armata) are found as isolated oases on mountaintops and along canyons with ephemeral flow conditions. Here, the effect of the interaction between the larva of an endemic moth, Litoprosopus bajaensis, and this endemic blue fan palm was documented for the first time. We registered the phenology of palms by counting the number of shoots with flowers or fruits, assessing their damage and calculating the reproductive success per individual palm within three populations: San Pedro Martir, Catavi?a, and La Libertad. Palm populations were severely impacted by this larva, causing high damage to the inflorescences. No differences were found in the number of inflorescence stems produced and damaged among study sites;but the reproductive success of palms was significantly higher in Catavi?a than in the other sites during the entire sampling period, and consequently an important proportion of stems escaped from the herbivore predation. We suggest that differences among sites may be explained by the fact that Catavi?a is the only alluvial canyon and can be considered an area of high nutrient uptake, resource availability, and rooting depths. In contrast the other two are bedrock canyons, where water runs intensely, sweeping away great portions of the nearby vegetation. Catavi?a received the highest precipitation during the winter season of 2010 allowing a continuous production of inflorescence stems and fruits. This preliminary study reveals a new endemic interaction, it occurrence at population and regional levels, and highlights the role of desert oases as resource patches and connectivity pathways for mobile insects. Finally, it also highlights the effects of different water flow dynamics and water pulses in providing an opportunity window of escape from predation for host plant species living in desert environments.展开更多
Aims To assess the role of moisture in phenological timing in the mediterranean coastal flora of Baja California,and specifically to assess the role of coastal fog and ocean-derived moisture in plant phenology.Moistur...Aims To assess the role of moisture in phenological timing in the mediterranean coastal flora of Baja California,and specifically to assess the role of coastal fog and ocean-derived moisture in plant phenology.Moisture seems to be the primary driver of flowering times and durations at the arid end of the mediterranean-climate region,where rainfall is often sporadic(temperature and day length can be expected to play a much lesser role as they are not growth limiting).We aimed to understand:What factors drive climatic variation between sites?Are there general flowering patterns allowing us to identify phenological categories?Do flowering patterns vary in relation to site-specific weather?and most importantly,does maritime influence on weather affect flowering dynamics in coastal mediterranean ecosystems?Methods The southernmost extent of the California Floristic Province(in Baja California,Mexico)is a biological diversity hotspot of high endemism and conservation value,with two steep moisture gradients:rainfall(N-S)and coastal fogs(W-E),providing an ideal study system.We installed five weather stations across the moisture gradients,recording data hourly.We monitored flowering phenology in the square kilometer surrounding each weather station from 2010 to 2013.About 86 plant taxa were monitored across the five sites,every 6-8 weeks.Averaged climatic data is presented with general trends in flowering,and specific flowering syndromes were observed.Data for flowering intensity across the sites was analyzed using a principal components analysis.Important Findings Data analysis demonstrates a general seasonal pattern in flowering times,but distinct differences in local weather and phenology between the five study sites.Three flowering syndromes are revealed in the flora:(i)water responders or spring bloomers,(ii)day-length responders or fall-blooming taxa and(iii)aseasonal bloomers with no seasonal affinity.The two moisture gradients are the strongest drivers of flowering times.Inland sites showed higher phenological variation than coastal sites where seasonality is dampened by ocean-derived moisture,which extends and buffers perennial plant phenology and is a probable driver of local endemism.Phenological controls vary globally with climate and geography;moisture is the primary driver of phenology in mediterranean climates and fog is an important climatic variable in coastal Mexico.展开更多
文摘In the Central Desert of northern Baja California, blue fan palm populations (Brahea armata) are found as isolated oases on mountaintops and along canyons with ephemeral flow conditions. Here, the effect of the interaction between the larva of an endemic moth, Litoprosopus bajaensis, and this endemic blue fan palm was documented for the first time. We registered the phenology of palms by counting the number of shoots with flowers or fruits, assessing their damage and calculating the reproductive success per individual palm within three populations: San Pedro Martir, Catavi?a, and La Libertad. Palm populations were severely impacted by this larva, causing high damage to the inflorescences. No differences were found in the number of inflorescence stems produced and damaged among study sites;but the reproductive success of palms was significantly higher in Catavi?a than in the other sites during the entire sampling period, and consequently an important proportion of stems escaped from the herbivore predation. We suggest that differences among sites may be explained by the fact that Catavi?a is the only alluvial canyon and can be considered an area of high nutrient uptake, resource availability, and rooting depths. In contrast the other two are bedrock canyons, where water runs intensely, sweeping away great portions of the nearby vegetation. Catavi?a received the highest precipitation during the winter season of 2010 allowing a continuous production of inflorescence stems and fruits. This preliminary study reveals a new endemic interaction, it occurrence at population and regional levels, and highlights the role of desert oases as resource patches and connectivity pathways for mobile insects. Finally, it also highlights the effects of different water flow dynamics and water pulses in providing an opportunity window of escape from predation for host plant species living in desert environments.
文摘Aims To assess the role of moisture in phenological timing in the mediterranean coastal flora of Baja California,and specifically to assess the role of coastal fog and ocean-derived moisture in plant phenology.Moisture seems to be the primary driver of flowering times and durations at the arid end of the mediterranean-climate region,where rainfall is often sporadic(temperature and day length can be expected to play a much lesser role as they are not growth limiting).We aimed to understand:What factors drive climatic variation between sites?Are there general flowering patterns allowing us to identify phenological categories?Do flowering patterns vary in relation to site-specific weather?and most importantly,does maritime influence on weather affect flowering dynamics in coastal mediterranean ecosystems?Methods The southernmost extent of the California Floristic Province(in Baja California,Mexico)is a biological diversity hotspot of high endemism and conservation value,with two steep moisture gradients:rainfall(N-S)and coastal fogs(W-E),providing an ideal study system.We installed five weather stations across the moisture gradients,recording data hourly.We monitored flowering phenology in the square kilometer surrounding each weather station from 2010 to 2013.About 86 plant taxa were monitored across the five sites,every 6-8 weeks.Averaged climatic data is presented with general trends in flowering,and specific flowering syndromes were observed.Data for flowering intensity across the sites was analyzed using a principal components analysis.Important Findings Data analysis demonstrates a general seasonal pattern in flowering times,but distinct differences in local weather and phenology between the five study sites.Three flowering syndromes are revealed in the flora:(i)water responders or spring bloomers,(ii)day-length responders or fall-blooming taxa and(iii)aseasonal bloomers with no seasonal affinity.The two moisture gradients are the strongest drivers of flowering times.Inland sites showed higher phenological variation than coastal sites where seasonality is dampened by ocean-derived moisture,which extends and buffers perennial plant phenology and is a probable driver of local endemism.Phenological controls vary globally with climate and geography;moisture is the primary driver of phenology in mediterranean climates and fog is an important climatic variable in coastal Mexico.
